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c906108c | 1 | \input texinfo @c -*-texinfo-*- |
c02a867d | 2 | @c Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, |
a67ec3f4 | 3 | @c 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 |
c906108c SS |
4 | @c Free Software Foundation, Inc. |
5 | @c | |
5d161b24 | 6 | @c %**start of header |
c906108c SS |
7 | @c makeinfo ignores cmds prev to setfilename, so its arg cannot make use |
8 | @c of @set vars. However, you can override filename with makeinfo -o. | |
9 | @setfilename gdb.info | |
10 | @c | |
11 | @include gdb-cfg.texi | |
12 | @c | |
c906108c | 13 | @settitle Debugging with @value{GDBN} |
c906108c SS |
14 | @setchapternewpage odd |
15 | @c %**end of header | |
16 | ||
17 | @iftex | |
18 | @c @smallbook | |
19 | @c @cropmarks | |
20 | @end iftex | |
21 | ||
22 | @finalout | |
23 | @syncodeindex ky cp | |
89c73ade | 24 | @syncodeindex tp cp |
c906108c | 25 | |
41afff9a | 26 | @c readline appendices use @vindex, @findex and @ftable, |
48e934c6 | 27 | @c annotate.texi and gdbmi use @findex. |
c906108c | 28 | @syncodeindex vr cp |
41afff9a | 29 | @syncodeindex fn cp |
c906108c SS |
30 | |
31 | @c !!set GDB manual's edition---not the same as GDB version! | |
9fe8321b | 32 | @c This is updated by GNU Press. |
e9c75b65 | 33 | @set EDITION Ninth |
c906108c | 34 | |
87885426 FN |
35 | @c !!set GDB edit command default editor |
36 | @set EDITOR /bin/ex | |
c906108c | 37 | |
6c0e9fb3 | 38 | @c THIS MANUAL REQUIRES TEXINFO 4.0 OR LATER. |
c906108c | 39 | |
c906108c | 40 | @c This is a dir.info fragment to support semi-automated addition of |
6d2ebf8b | 41 | @c manuals to an info tree. |
03727ca6 | 42 | @dircategory Software development |
96a2c332 | 43 | @direntry |
03727ca6 | 44 | * Gdb: (gdb). The GNU debugger. |
96a2c332 SS |
45 | @end direntry |
46 | ||
a67ec3f4 JM |
47 | @copying |
48 | Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, | |
49 | 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 | |
50 | Free Software Foundation, Inc. | |
c906108c | 51 | |
e9c75b65 EZ |
52 | Permission is granted to copy, distribute and/or modify this document |
53 | under the terms of the GNU Free Documentation License, Version 1.1 or | |
54 | any later version published by the Free Software Foundation; with the | |
959acfd1 EZ |
55 | Invariant Sections being ``Free Software'' and ``Free Software Needs |
56 | Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' | |
57 | and with the Back-Cover Texts as in (a) below. | |
c906108c | 58 | |
b8533aec DJ |
59 | (a) The FSF's Back-Cover Text is: ``You are free to copy and modify |
60 | this GNU Manual. Buying copies from GNU Press supports the FSF in | |
61 | developing GNU and promoting software freedom.'' | |
a67ec3f4 JM |
62 | @end copying |
63 | ||
64 | @ifnottex | |
65 | This file documents the @sc{gnu} debugger @value{GDBN}. | |
66 | ||
67 | This is the @value{EDITION} Edition, of @cite{Debugging with | |
68 | @value{GDBN}: the @sc{gnu} Source-Level Debugger} for @value{GDBN} | |
69 | @ifset VERSION_PACKAGE | |
70 | @value{VERSION_PACKAGE} | |
71 | @end ifset | |
72 | Version @value{GDBVN}. | |
73 | ||
74 | @insertcopying | |
75 | @end ifnottex | |
c906108c SS |
76 | |
77 | @titlepage | |
78 | @title Debugging with @value{GDBN} | |
79 | @subtitle The @sc{gnu} Source-Level Debugger | |
c906108c | 80 | @sp 1 |
c906108c | 81 | @subtitle @value{EDITION} Edition, for @value{GDBN} version @value{GDBVN} |
c16158bc JM |
82 | @ifset VERSION_PACKAGE |
83 | @sp 1 | |
84 | @subtitle @value{VERSION_PACKAGE} | |
85 | @end ifset | |
9e9c5ae7 | 86 | @author Richard Stallman, Roland Pesch, Stan Shebs, et al. |
c906108c | 87 | @page |
c906108c SS |
88 | @tex |
89 | {\parskip=0pt | |
c16158bc | 90 | \hfill (Send bugs and comments on @value{GDBN} to @value{BUGURL}.)\par |
c906108c SS |
91 | \hfill {\it Debugging with @value{GDBN}}\par |
92 | \hfill \TeX{}info \texinfoversion\par | |
93 | } | |
94 | @end tex | |
53a5351d | 95 | |
c906108c | 96 | @vskip 0pt plus 1filll |
c906108c | 97 | Published by the Free Software Foundation @* |
c02a867d EZ |
98 | 51 Franklin Street, Fifth Floor, |
99 | Boston, MA 02110-1301, USA@* | |
6d2ebf8b | 100 | ISBN 1-882114-77-9 @* |
e9c75b65 | 101 | |
a67ec3f4 | 102 | @insertcopying |
3fb6a982 JB |
103 | @page |
104 | This edition of the GDB manual is dedicated to the memory of Fred | |
105 | Fish. Fred was a long-standing contributor to GDB and to Free | |
106 | software in general. We will miss him. | |
c906108c SS |
107 | @end titlepage |
108 | @page | |
109 | ||
6c0e9fb3 | 110 | @ifnottex |
6d2ebf8b SS |
111 | @node Top, Summary, (dir), (dir) |
112 | ||
c906108c SS |
113 | @top Debugging with @value{GDBN} |
114 | ||
115 | This file describes @value{GDBN}, the @sc{gnu} symbolic debugger. | |
116 | ||
c16158bc JM |
117 | This is the @value{EDITION} Edition, for @value{GDBN} |
118 | @ifset VERSION_PACKAGE | |
119 | @value{VERSION_PACKAGE} | |
120 | @end ifset | |
121 | Version @value{GDBVN}. | |
c906108c | 122 | |
a67ec3f4 | 123 | Copyright (C) 1988-2009 Free Software Foundation, Inc. |
6d2ebf8b | 124 | |
3fb6a982 JB |
125 | This edition of the GDB manual is dedicated to the memory of Fred |
126 | Fish. Fred was a long-standing contributor to GDB and to Free | |
127 | software in general. We will miss him. | |
128 | ||
6d2ebf8b SS |
129 | @menu |
130 | * Summary:: Summary of @value{GDBN} | |
131 | * Sample Session:: A sample @value{GDBN} session | |
132 | ||
133 | * Invocation:: Getting in and out of @value{GDBN} | |
134 | * Commands:: @value{GDBN} commands | |
135 | * Running:: Running programs under @value{GDBN} | |
136 | * Stopping:: Stopping and continuing | |
bacec72f | 137 | * Reverse Execution:: Running programs backward |
a2311334 | 138 | * Process Record and Replay:: Recording inferior's execution and replaying it |
6d2ebf8b SS |
139 | * Stack:: Examining the stack |
140 | * Source:: Examining source files | |
141 | * Data:: Examining data | |
edb3359d | 142 | * Optimized Code:: Debugging optimized code |
e2e0bcd1 | 143 | * Macros:: Preprocessor Macros |
b37052ae | 144 | * Tracepoints:: Debugging remote targets non-intrusively |
df0cd8c5 | 145 | * Overlays:: Debugging programs that use overlays |
6d2ebf8b SS |
146 | |
147 | * Languages:: Using @value{GDBN} with different languages | |
148 | ||
149 | * Symbols:: Examining the symbol table | |
150 | * Altering:: Altering execution | |
151 | * GDB Files:: @value{GDBN} files | |
152 | * Targets:: Specifying a debugging target | |
6b2f586d | 153 | * Remote Debugging:: Debugging remote programs |
6d2ebf8b SS |
154 | * Configurations:: Configuration-specific information |
155 | * Controlling GDB:: Controlling @value{GDBN} | |
d57a3c85 | 156 | * Extending GDB:: Extending @value{GDBN} |
21c294e6 | 157 | * Interpreters:: Command Interpreters |
c8f4133a | 158 | * TUI:: @value{GDBN} Text User Interface |
6d2ebf8b | 159 | * Emacs:: Using @value{GDBN} under @sc{gnu} Emacs |
7162c0ca | 160 | * GDB/MI:: @value{GDBN}'s Machine Interface. |
c8f4133a | 161 | * Annotations:: @value{GDBN}'s annotation interface. |
4efc6507 | 162 | * JIT Interface:: Using the JIT debugging interface. |
6d2ebf8b SS |
163 | |
164 | * GDB Bugs:: Reporting bugs in @value{GDBN} | |
6d2ebf8b SS |
165 | |
166 | * Command Line Editing:: Command Line Editing | |
167 | * Using History Interactively:: Using History Interactively | |
0869d01b | 168 | * Formatting Documentation:: How to format and print @value{GDBN} documentation |
6d2ebf8b | 169 | * Installing GDB:: Installing GDB |
eb12ee30 | 170 | * Maintenance Commands:: Maintenance Commands |
e0ce93ac | 171 | * Remote Protocol:: GDB Remote Serial Protocol |
f418dd93 | 172 | * Agent Expressions:: The GDB Agent Expression Mechanism |
23181151 DJ |
173 | * Target Descriptions:: How targets can describe themselves to |
174 | @value{GDBN} | |
07e059b5 VP |
175 | * Operating System Information:: Getting additional information from |
176 | the operating system | |
aab4e0ec AC |
177 | * Copying:: GNU General Public License says |
178 | how you can copy and share GDB | |
6826cf00 | 179 | * GNU Free Documentation License:: The license for this documentation |
6d2ebf8b SS |
180 | * Index:: Index |
181 | @end menu | |
182 | ||
6c0e9fb3 | 183 | @end ifnottex |
c906108c | 184 | |
449f3b6c | 185 | @contents |
449f3b6c | 186 | |
6d2ebf8b | 187 | @node Summary |
c906108c SS |
188 | @unnumbered Summary of @value{GDBN} |
189 | ||
190 | The purpose of a debugger such as @value{GDBN} is to allow you to see what is | |
191 | going on ``inside'' another program while it executes---or what another | |
192 | program was doing at the moment it crashed. | |
193 | ||
194 | @value{GDBN} can do four main kinds of things (plus other things in support of | |
195 | these) to help you catch bugs in the act: | |
196 | ||
197 | @itemize @bullet | |
198 | @item | |
199 | Start your program, specifying anything that might affect its behavior. | |
200 | ||
201 | @item | |
202 | Make your program stop on specified conditions. | |
203 | ||
204 | @item | |
205 | Examine what has happened, when your program has stopped. | |
206 | ||
207 | @item | |
208 | Change things in your program, so you can experiment with correcting the | |
209 | effects of one bug and go on to learn about another. | |
210 | @end itemize | |
211 | ||
49efadf5 | 212 | You can use @value{GDBN} to debug programs written in C and C@t{++}. |
79a6e687 | 213 | For more information, see @ref{Supported Languages,,Supported Languages}. |
c906108c SS |
214 | For more information, see @ref{C,,C and C++}. |
215 | ||
cce74817 | 216 | @cindex Modula-2 |
e632838e AC |
217 | Support for Modula-2 is partial. For information on Modula-2, see |
218 | @ref{Modula-2,,Modula-2}. | |
c906108c | 219 | |
cce74817 JM |
220 | @cindex Pascal |
221 | Debugging Pascal programs which use sets, subranges, file variables, or | |
222 | nested functions does not currently work. @value{GDBN} does not support | |
223 | entering expressions, printing values, or similar features using Pascal | |
224 | syntax. | |
c906108c | 225 | |
c906108c SS |
226 | @cindex Fortran |
227 | @value{GDBN} can be used to debug programs written in Fortran, although | |
53a5351d | 228 | it may be necessary to refer to some variables with a trailing |
cce74817 | 229 | underscore. |
c906108c | 230 | |
b37303ee AF |
231 | @value{GDBN} can be used to debug programs written in Objective-C, |
232 | using either the Apple/NeXT or the GNU Objective-C runtime. | |
233 | ||
c906108c SS |
234 | @menu |
235 | * Free Software:: Freely redistributable software | |
236 | * Contributors:: Contributors to GDB | |
237 | @end menu | |
238 | ||
6d2ebf8b | 239 | @node Free Software |
79a6e687 | 240 | @unnumberedsec Free Software |
c906108c | 241 | |
5d161b24 | 242 | @value{GDBN} is @dfn{free software}, protected by the @sc{gnu} |
c906108c SS |
243 | General Public License |
244 | (GPL). The GPL gives you the freedom to copy or adapt a licensed | |
245 | program---but every person getting a copy also gets with it the | |
246 | freedom to modify that copy (which means that they must get access to | |
247 | the source code), and the freedom to distribute further copies. | |
248 | Typical software companies use copyrights to limit your freedoms; the | |
249 | Free Software Foundation uses the GPL to preserve these freedoms. | |
250 | ||
251 | Fundamentally, the General Public License is a license which says that | |
252 | you have these freedoms and that you cannot take these freedoms away | |
253 | from anyone else. | |
254 | ||
2666264b | 255 | @unnumberedsec Free Software Needs Free Documentation |
959acfd1 EZ |
256 | |
257 | The biggest deficiency in the free software community today is not in | |
258 | the software---it is the lack of good free documentation that we can | |
259 | include with the free software. Many of our most important | |
260 | programs do not come with free reference manuals and free introductory | |
261 | texts. Documentation is an essential part of any software package; | |
262 | when an important free software package does not come with a free | |
263 | manual and a free tutorial, that is a major gap. We have many such | |
264 | gaps today. | |
265 | ||
266 | Consider Perl, for instance. The tutorial manuals that people | |
267 | normally use are non-free. How did this come about? Because the | |
268 | authors of those manuals published them with restrictive terms---no | |
269 | copying, no modification, source files not available---which exclude | |
270 | them from the free software world. | |
271 | ||
272 | That wasn't the first time this sort of thing happened, and it was far | |
273 | from the last. Many times we have heard a GNU user eagerly describe a | |
274 | manual that he is writing, his intended contribution to the community, | |
275 | only to learn that he had ruined everything by signing a publication | |
276 | contract to make it non-free. | |
277 | ||
278 | Free documentation, like free software, is a matter of freedom, not | |
279 | price. The problem with the non-free manual is not that publishers | |
280 | charge a price for printed copies---that in itself is fine. (The Free | |
281 | Software Foundation sells printed copies of manuals, too.) The | |
282 | problem is the restrictions on the use of the manual. Free manuals | |
283 | are available in source code form, and give you permission to copy and | |
284 | modify. Non-free manuals do not allow this. | |
285 | ||
286 | The criteria of freedom for a free manual are roughly the same as for | |
287 | free software. Redistribution (including the normal kinds of | |
288 | commercial redistribution) must be permitted, so that the manual can | |
289 | accompany every copy of the program, both on-line and on paper. | |
290 | ||
291 | Permission for modification of the technical content is crucial too. | |
292 | When people modify the software, adding or changing features, if they | |
293 | are conscientious they will change the manual too---so they can | |
294 | provide accurate and clear documentation for the modified program. A | |
295 | manual that leaves you no choice but to write a new manual to document | |
296 | a changed version of the program is not really available to our | |
297 | community. | |
298 | ||
299 | Some kinds of limits on the way modification is handled are | |
300 | acceptable. For example, requirements to preserve the original | |
301 | author's copyright notice, the distribution terms, or the list of | |
302 | authors, are ok. It is also no problem to require modified versions | |
303 | to include notice that they were modified. Even entire sections that | |
304 | may not be deleted or changed are acceptable, as long as they deal | |
305 | with nontechnical topics (like this one). These kinds of restrictions | |
306 | are acceptable because they don't obstruct the community's normal use | |
307 | of the manual. | |
308 | ||
309 | However, it must be possible to modify all the @emph{technical} | |
310 | content of the manual, and then distribute the result in all the usual | |
311 | media, through all the usual channels. Otherwise, the restrictions | |
312 | obstruct the use of the manual, it is not free, and we need another | |
313 | manual to replace it. | |
314 | ||
315 | Please spread the word about this issue. Our community continues to | |
316 | lose manuals to proprietary publishing. If we spread the word that | |
317 | free software needs free reference manuals and free tutorials, perhaps | |
318 | the next person who wants to contribute by writing documentation will | |
319 | realize, before it is too late, that only free manuals contribute to | |
320 | the free software community. | |
321 | ||
322 | If you are writing documentation, please insist on publishing it under | |
323 | the GNU Free Documentation License or another free documentation | |
324 | license. Remember that this decision requires your approval---you | |
325 | don't have to let the publisher decide. Some commercial publishers | |
326 | will use a free license if you insist, but they will not propose the | |
327 | option; it is up to you to raise the issue and say firmly that this is | |
328 | what you want. If the publisher you are dealing with refuses, please | |
329 | try other publishers. If you're not sure whether a proposed license | |
42584a72 | 330 | is free, write to @email{licensing@@gnu.org}. |
959acfd1 EZ |
331 | |
332 | You can encourage commercial publishers to sell more free, copylefted | |
333 | manuals and tutorials by buying them, and particularly by buying | |
334 | copies from the publishers that paid for their writing or for major | |
335 | improvements. Meanwhile, try to avoid buying non-free documentation | |
336 | at all. Check the distribution terms of a manual before you buy it, | |
337 | and insist that whoever seeks your business must respect your freedom. | |
72c9928d EZ |
338 | Check the history of the book, and try to reward the publishers that |
339 | have paid or pay the authors to work on it. | |
959acfd1 EZ |
340 | |
341 | The Free Software Foundation maintains a list of free documentation | |
342 | published by other publishers, at | |
343 | @url{http://www.fsf.org/doc/other-free-books.html}. | |
344 | ||
6d2ebf8b | 345 | @node Contributors |
96a2c332 SS |
346 | @unnumberedsec Contributors to @value{GDBN} |
347 | ||
348 | Richard Stallman was the original author of @value{GDBN}, and of many | |
349 | other @sc{gnu} programs. Many others have contributed to its | |
350 | development. This section attempts to credit major contributors. One | |
351 | of the virtues of free software is that everyone is free to contribute | |
352 | to it; with regret, we cannot actually acknowledge everyone here. The | |
353 | file @file{ChangeLog} in the @value{GDBN} distribution approximates a | |
c906108c SS |
354 | blow-by-blow account. |
355 | ||
356 | Changes much prior to version 2.0 are lost in the mists of time. | |
357 | ||
358 | @quotation | |
359 | @emph{Plea:} Additions to this section are particularly welcome. If you | |
360 | or your friends (or enemies, to be evenhanded) have been unfairly | |
361 | omitted from this list, we would like to add your names! | |
362 | @end quotation | |
363 | ||
364 | So that they may not regard their many labors as thankless, we | |
365 | particularly thank those who shepherded @value{GDBN} through major | |
366 | releases: | |
7ba3cf9c | 367 | Andrew Cagney (releases 6.3, 6.2, 6.1, 6.0, 5.3, 5.2, 5.1 and 5.0); |
c906108c SS |
368 | Jim Blandy (release 4.18); |
369 | Jason Molenda (release 4.17); | |
370 | Stan Shebs (release 4.14); | |
371 | Fred Fish (releases 4.16, 4.15, 4.13, 4.12, 4.11, 4.10, and 4.9); | |
372 | Stu Grossman and John Gilmore (releases 4.8, 4.7, 4.6, 4.5, and 4.4); | |
373 | John Gilmore (releases 4.3, 4.2, 4.1, 4.0, and 3.9); | |
374 | Jim Kingdon (releases 3.5, 3.4, and 3.3); | |
375 | and Randy Smith (releases 3.2, 3.1, and 3.0). | |
376 | ||
377 | Richard Stallman, assisted at various times by Peter TerMaat, Chris | |
378 | Hanson, and Richard Mlynarik, handled releases through 2.8. | |
379 | ||
b37052ae EZ |
380 | Michael Tiemann is the author of most of the @sc{gnu} C@t{++} support |
381 | in @value{GDBN}, with significant additional contributions from Per | |
382 | Bothner and Daniel Berlin. James Clark wrote the @sc{gnu} C@t{++} | |
383 | demangler. Early work on C@t{++} was by Peter TerMaat (who also did | |
384 | much general update work leading to release 3.0). | |
c906108c | 385 | |
b37052ae | 386 | @value{GDBN} uses the BFD subroutine library to examine multiple |
c906108c SS |
387 | object-file formats; BFD was a joint project of David V. |
388 | Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore. | |
389 | ||
390 | David Johnson wrote the original COFF support; Pace Willison did | |
391 | the original support for encapsulated COFF. | |
392 | ||
0179ffac | 393 | Brent Benson of Harris Computer Systems contributed DWARF 2 support. |
c906108c SS |
394 | |
395 | Adam de Boor and Bradley Davis contributed the ISI Optimum V support. | |
396 | Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS | |
397 | support. | |
398 | Jean-Daniel Fekete contributed Sun 386i support. | |
399 | Chris Hanson improved the HP9000 support. | |
400 | Noboyuki Hikichi and Tomoyuki Hasei contributed Sony/News OS 3 support. | |
401 | David Johnson contributed Encore Umax support. | |
402 | Jyrki Kuoppala contributed Altos 3068 support. | |
403 | Jeff Law contributed HP PA and SOM support. | |
404 | Keith Packard contributed NS32K support. | |
405 | Doug Rabson contributed Acorn Risc Machine support. | |
406 | Bob Rusk contributed Harris Nighthawk CX-UX support. | |
407 | Chris Smith contributed Convex support (and Fortran debugging). | |
408 | Jonathan Stone contributed Pyramid support. | |
409 | Michael Tiemann contributed SPARC support. | |
410 | Tim Tucker contributed support for the Gould NP1 and Gould Powernode. | |
411 | Pace Willison contributed Intel 386 support. | |
412 | Jay Vosburgh contributed Symmetry support. | |
a37295f9 | 413 | Marko Mlinar contributed OpenRISC 1000 support. |
c906108c | 414 | |
1104b9e7 | 415 | Andreas Schwab contributed M68K @sc{gnu}/Linux support. |
c906108c SS |
416 | |
417 | Rich Schaefer and Peter Schauer helped with support of SunOS shared | |
418 | libraries. | |
419 | ||
420 | Jay Fenlason and Roland McGrath ensured that @value{GDBN} and GAS agree | |
421 | about several machine instruction sets. | |
422 | ||
423 | Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped develop | |
424 | remote debugging. Intel Corporation, Wind River Systems, AMD, and ARM | |
425 | contributed remote debugging modules for the i960, VxWorks, A29K UDI, | |
426 | and RDI targets, respectively. | |
427 | ||
428 | Brian Fox is the author of the readline libraries providing | |
429 | command-line editing and command history. | |
430 | ||
7a292a7a SS |
431 | Andrew Beers of SUNY Buffalo wrote the language-switching code, the |
432 | Modula-2 support, and contributed the Languages chapter of this manual. | |
c906108c | 433 | |
5d161b24 | 434 | Fred Fish wrote most of the support for Unix System Vr4. |
b37052ae | 435 | He also enhanced the command-completion support to cover C@t{++} overloaded |
c906108c | 436 | symbols. |
c906108c | 437 | |
f24c5e49 KI |
438 | Hitachi America (now Renesas America), Ltd. sponsored the support for |
439 | H8/300, H8/500, and Super-H processors. | |
c906108c SS |
440 | |
441 | NEC sponsored the support for the v850, Vr4xxx, and Vr5xxx processors. | |
442 | ||
f24c5e49 KI |
443 | Mitsubishi (now Renesas) sponsored the support for D10V, D30V, and M32R/D |
444 | processors. | |
c906108c SS |
445 | |
446 | Toshiba sponsored the support for the TX39 Mips processor. | |
447 | ||
448 | Matsushita sponsored the support for the MN10200 and MN10300 processors. | |
449 | ||
96a2c332 | 450 | Fujitsu sponsored the support for SPARClite and FR30 processors. |
c906108c SS |
451 | |
452 | Kung Hsu, Jeff Law, and Rick Sladkey added support for hardware | |
453 | watchpoints. | |
454 | ||
455 | Michael Snyder added support for tracepoints. | |
456 | ||
457 | Stu Grossman wrote gdbserver. | |
458 | ||
459 | Jim Kingdon, Peter Schauer, Ian Taylor, and Stu Grossman made | |
96a2c332 | 460 | nearly innumerable bug fixes and cleanups throughout @value{GDBN}. |
c906108c SS |
461 | |
462 | The following people at the Hewlett-Packard Company contributed | |
463 | support for the PA-RISC 2.0 architecture, HP-UX 10.20, 10.30, and 11.0 | |
b37052ae | 464 | (narrow mode), HP's implementation of kernel threads, HP's aC@t{++} |
d0d5df6f AC |
465 | compiler, and the Text User Interface (nee Terminal User Interface): |
466 | Ben Krepp, Richard Title, John Bishop, Susan Macchia, Kathy Mann, | |
467 | Satish Pai, India Paul, Steve Rehrauer, and Elena Zannoni. Kim Haase | |
468 | provided HP-specific information in this manual. | |
c906108c | 469 | |
b37052ae EZ |
470 | DJ Delorie ported @value{GDBN} to MS-DOS, for the DJGPP project. |
471 | Robert Hoehne made significant contributions to the DJGPP port. | |
472 | ||
96a2c332 SS |
473 | Cygnus Solutions has sponsored @value{GDBN} maintenance and much of its |
474 | development since 1991. Cygnus engineers who have worked on @value{GDBN} | |
2df3850c JM |
475 | fulltime include Mark Alexander, Jim Blandy, Per Bothner, Kevin |
476 | Buettner, Edith Epstein, Chris Faylor, Fred Fish, Martin Hunt, Jim | |
477 | Ingham, John Gilmore, Stu Grossman, Kung Hsu, Jim Kingdon, John Metzler, | |
478 | Fernando Nasser, Geoffrey Noer, Dawn Perchik, Rich Pixley, Zdenek | |
479 | Radouch, Keith Seitz, Stan Shebs, David Taylor, and Elena Zannoni. In | |
480 | addition, Dave Brolley, Ian Carmichael, Steve Chamberlain, Nick Clifton, | |
481 | JT Conklin, Stan Cox, DJ Delorie, Ulrich Drepper, Frank Eigler, Doug | |
482 | Evans, Sean Fagan, David Henkel-Wallace, Richard Henderson, Jeff | |
483 | Holcomb, Jeff Law, Jim Lemke, Tom Lord, Bob Manson, Michael Meissner, | |
484 | Jason Merrill, Catherine Moore, Drew Moseley, Ken Raeburn, Gavin | |
485 | Romig-Koch, Rob Savoye, Jamie Smith, Mike Stump, Ian Taylor, Angela | |
486 | Thomas, Michael Tiemann, Tom Tromey, Ron Unrau, Jim Wilson, and David | |
487 | Zuhn have made contributions both large and small. | |
c906108c | 488 | |
ffed4509 AC |
489 | Andrew Cagney, Fernando Nasser, and Elena Zannoni, while working for |
490 | Cygnus Solutions, implemented the original @sc{gdb/mi} interface. | |
491 | ||
e2e0bcd1 JB |
492 | Jim Blandy added support for preprocessor macros, while working for Red |
493 | Hat. | |
c906108c | 494 | |
a9967aef AC |
495 | Andrew Cagney designed @value{GDBN}'s architecture vector. Many |
496 | people including Andrew Cagney, Stephane Carrez, Randolph Chung, Nick | |
497 | Duffek, Richard Henderson, Mark Kettenis, Grace Sainsbury, Kei | |
498 | Sakamoto, Yoshinori Sato, Michael Snyder, Andreas Schwab, Jason | |
499 | Thorpe, Corinna Vinschen, Ulrich Weigand, and Elena Zannoni, helped | |
500 | with the migration of old architectures to this new framework. | |
501 | ||
c5e30d01 AC |
502 | Andrew Cagney completely re-designed and re-implemented @value{GDBN}'s |
503 | unwinder framework, this consisting of a fresh new design featuring | |
504 | frame IDs, independent frame sniffers, and the sentinel frame. Mark | |
505 | Kettenis implemented the @sc{dwarf 2} unwinder, Jeff Johnston the | |
506 | libunwind unwinder, and Andrew Cagney the dummy, sentinel, tramp, and | |
db2e3e2e | 507 | trad unwinders. The architecture-specific changes, each involving a |
c5e30d01 AC |
508 | complete rewrite of the architecture's frame code, were carried out by |
509 | Jim Blandy, Joel Brobecker, Kevin Buettner, Andrew Cagney, Stephane | |
510 | Carrez, Randolph Chung, Orjan Friberg, Richard Henderson, Daniel | |
511 | Jacobowitz, Jeff Johnston, Mark Kettenis, Theodore A. Roth, Kei | |
512 | Sakamoto, Yoshinori Sato, Michael Snyder, Corinna Vinschen, and Ulrich | |
513 | Weigand. | |
514 | ||
ca3bf3bd DJ |
515 | Christian Zankel, Ross Morley, Bob Wilson, and Maxim Grigoriev from |
516 | Tensilica, Inc.@: contributed support for Xtensa processors. Others | |
517 | who have worked on the Xtensa port of @value{GDBN} in the past include | |
518 | Steve Tjiang, John Newlin, and Scott Foehner. | |
519 | ||
6d2ebf8b | 520 | @node Sample Session |
c906108c SS |
521 | @chapter A Sample @value{GDBN} Session |
522 | ||
523 | You can use this manual at your leisure to read all about @value{GDBN}. | |
524 | However, a handful of commands are enough to get started using the | |
525 | debugger. This chapter illustrates those commands. | |
526 | ||
527 | @iftex | |
528 | In this sample session, we emphasize user input like this: @b{input}, | |
529 | to make it easier to pick out from the surrounding output. | |
530 | @end iftex | |
531 | ||
532 | @c FIXME: this example may not be appropriate for some configs, where | |
533 | @c FIXME...primary interest is in remote use. | |
534 | ||
535 | One of the preliminary versions of @sc{gnu} @code{m4} (a generic macro | |
536 | processor) exhibits the following bug: sometimes, when we change its | |
537 | quote strings from the default, the commands used to capture one macro | |
538 | definition within another stop working. In the following short @code{m4} | |
539 | session, we define a macro @code{foo} which expands to @code{0000}; we | |
540 | then use the @code{m4} built-in @code{defn} to define @code{bar} as the | |
541 | same thing. However, when we change the open quote string to | |
542 | @code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same | |
543 | procedure fails to define a new synonym @code{baz}: | |
544 | ||
545 | @smallexample | |
546 | $ @b{cd gnu/m4} | |
547 | $ @b{./m4} | |
548 | @b{define(foo,0000)} | |
549 | ||
550 | @b{foo} | |
551 | 0000 | |
552 | @b{define(bar,defn(`foo'))} | |
553 | ||
554 | @b{bar} | |
555 | 0000 | |
556 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
557 | ||
558 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
559 | @b{baz} | |
c8aa23ab | 560 | @b{Ctrl-d} |
c906108c SS |
561 | m4: End of input: 0: fatal error: EOF in string |
562 | @end smallexample | |
563 | ||
564 | @noindent | |
565 | Let us use @value{GDBN} to try to see what is going on. | |
566 | ||
c906108c SS |
567 | @smallexample |
568 | $ @b{@value{GDBP} m4} | |
569 | @c FIXME: this falsifies the exact text played out, to permit smallbook | |
570 | @c FIXME... format to come out better. | |
571 | @value{GDBN} is free software and you are welcome to distribute copies | |
5d161b24 | 572 | of it under certain conditions; type "show copying" to see |
c906108c | 573 | the conditions. |
5d161b24 | 574 | There is absolutely no warranty for @value{GDBN}; type "show warranty" |
c906108c SS |
575 | for details. |
576 | ||
577 | @value{GDBN} @value{GDBVN}, Copyright 1999 Free Software Foundation, Inc... | |
578 | (@value{GDBP}) | |
579 | @end smallexample | |
c906108c SS |
580 | |
581 | @noindent | |
582 | @value{GDBN} reads only enough symbol data to know where to find the | |
583 | rest when needed; as a result, the first prompt comes up very quickly. | |
584 | We now tell @value{GDBN} to use a narrower display width than usual, so | |
585 | that examples fit in this manual. | |
586 | ||
587 | @smallexample | |
588 | (@value{GDBP}) @b{set width 70} | |
589 | @end smallexample | |
590 | ||
591 | @noindent | |
592 | We need to see how the @code{m4} built-in @code{changequote} works. | |
593 | Having looked at the source, we know the relevant subroutine is | |
594 | @code{m4_changequote}, so we set a breakpoint there with the @value{GDBN} | |
595 | @code{break} command. | |
596 | ||
597 | @smallexample | |
598 | (@value{GDBP}) @b{break m4_changequote} | |
599 | Breakpoint 1 at 0x62f4: file builtin.c, line 879. | |
600 | @end smallexample | |
601 | ||
602 | @noindent | |
603 | Using the @code{run} command, we start @code{m4} running under @value{GDBN} | |
604 | control; as long as control does not reach the @code{m4_changequote} | |
605 | subroutine, the program runs as usual: | |
606 | ||
607 | @smallexample | |
608 | (@value{GDBP}) @b{run} | |
609 | Starting program: /work/Editorial/gdb/gnu/m4/m4 | |
610 | @b{define(foo,0000)} | |
611 | ||
612 | @b{foo} | |
613 | 0000 | |
614 | @end smallexample | |
615 | ||
616 | @noindent | |
617 | To trigger the breakpoint, we call @code{changequote}. @value{GDBN} | |
618 | suspends execution of @code{m4}, displaying information about the | |
619 | context where it stops. | |
620 | ||
621 | @smallexample | |
622 | @b{changequote(<QUOTE>,<UNQUOTE>)} | |
623 | ||
5d161b24 | 624 | Breakpoint 1, m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
625 | at builtin.c:879 |
626 | 879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]),argc,1,3)) | |
627 | @end smallexample | |
628 | ||
629 | @noindent | |
630 | Now we use the command @code{n} (@code{next}) to advance execution to | |
631 | the next line of the current function. | |
632 | ||
633 | @smallexample | |
634 | (@value{GDBP}) @b{n} | |
635 | 882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\ | |
636 | : nil, | |
637 | @end smallexample | |
638 | ||
639 | @noindent | |
640 | @code{set_quotes} looks like a promising subroutine. We can go into it | |
641 | by using the command @code{s} (@code{step}) instead of @code{next}. | |
642 | @code{step} goes to the next line to be executed in @emph{any} | |
643 | subroutine, so it steps into @code{set_quotes}. | |
644 | ||
645 | @smallexample | |
646 | (@value{GDBP}) @b{s} | |
647 | set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
648 | at input.c:530 | |
649 | 530 if (lquote != def_lquote) | |
650 | @end smallexample | |
651 | ||
652 | @noindent | |
653 | The display that shows the subroutine where @code{m4} is now | |
654 | suspended (and its arguments) is called a stack frame display. It | |
655 | shows a summary of the stack. We can use the @code{backtrace} | |
656 | command (which can also be spelled @code{bt}), to see where we are | |
657 | in the stack as a whole: the @code{backtrace} command displays a | |
658 | stack frame for each active subroutine. | |
659 | ||
660 | @smallexample | |
661 | (@value{GDBP}) @b{bt} | |
662 | #0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>") | |
663 | at input.c:530 | |
5d161b24 | 664 | #1 0x6344 in m4_changequote (argc=3, argv=0x33c70) |
c906108c SS |
665 | at builtin.c:882 |
666 | #2 0x8174 in expand_macro (sym=0x33320) at macro.c:242 | |
667 | #3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30) | |
668 | at macro.c:71 | |
669 | #4 0x79dc in expand_input () at macro.c:40 | |
670 | #5 0x2930 in main (argc=0, argv=0xf7fffb20) at m4.c:195 | |
671 | @end smallexample | |
672 | ||
673 | @noindent | |
674 | We step through a few more lines to see what happens. The first two | |
675 | times, we can use @samp{s}; the next two times we use @code{n} to avoid | |
676 | falling into the @code{xstrdup} subroutine. | |
677 | ||
678 | @smallexample | |
679 | (@value{GDBP}) @b{s} | |
680 | 0x3b5c 532 if (rquote != def_rquote) | |
681 | (@value{GDBP}) @b{s} | |
682 | 0x3b80 535 lquote = (lq == nil || *lq == '\0') ? \ | |
683 | def_lquote : xstrdup(lq); | |
684 | (@value{GDBP}) @b{n} | |
685 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
686 | : xstrdup(rq); | |
687 | (@value{GDBP}) @b{n} | |
688 | 538 len_lquote = strlen(rquote); | |
689 | @end smallexample | |
690 | ||
691 | @noindent | |
692 | The last line displayed looks a little odd; we can examine the variables | |
693 | @code{lquote} and @code{rquote} to see if they are in fact the new left | |
694 | and right quotes we specified. We use the command @code{p} | |
695 | (@code{print}) to see their values. | |
696 | ||
697 | @smallexample | |
698 | (@value{GDBP}) @b{p lquote} | |
699 | $1 = 0x35d40 "<QUOTE>" | |
700 | (@value{GDBP}) @b{p rquote} | |
701 | $2 = 0x35d50 "<UNQUOTE>" | |
702 | @end smallexample | |
703 | ||
704 | @noindent | |
705 | @code{lquote} and @code{rquote} are indeed the new left and right quotes. | |
706 | To look at some context, we can display ten lines of source | |
707 | surrounding the current line with the @code{l} (@code{list}) command. | |
708 | ||
709 | @smallexample | |
710 | (@value{GDBP}) @b{l} | |
711 | 533 xfree(rquote); | |
712 | 534 | |
713 | 535 lquote = (lq == nil || *lq == '\0') ? def_lquote\ | |
714 | : xstrdup (lq); | |
715 | 536 rquote = (rq == nil || *rq == '\0') ? def_rquote\ | |
716 | : xstrdup (rq); | |
717 | 537 | |
718 | 538 len_lquote = strlen(rquote); | |
719 | 539 len_rquote = strlen(lquote); | |
720 | 540 @} | |
721 | 541 | |
722 | 542 void | |
723 | @end smallexample | |
724 | ||
725 | @noindent | |
726 | Let us step past the two lines that set @code{len_lquote} and | |
727 | @code{len_rquote}, and then examine the values of those variables. | |
728 | ||
729 | @smallexample | |
730 | (@value{GDBP}) @b{n} | |
731 | 539 len_rquote = strlen(lquote); | |
732 | (@value{GDBP}) @b{n} | |
733 | 540 @} | |
734 | (@value{GDBP}) @b{p len_lquote} | |
735 | $3 = 9 | |
736 | (@value{GDBP}) @b{p len_rquote} | |
737 | $4 = 7 | |
738 | @end smallexample | |
739 | ||
740 | @noindent | |
741 | That certainly looks wrong, assuming @code{len_lquote} and | |
742 | @code{len_rquote} are meant to be the lengths of @code{lquote} and | |
743 | @code{rquote} respectively. We can set them to better values using | |
744 | the @code{p} command, since it can print the value of | |
745 | any expression---and that expression can include subroutine calls and | |
746 | assignments. | |
747 | ||
748 | @smallexample | |
749 | (@value{GDBP}) @b{p len_lquote=strlen(lquote)} | |
750 | $5 = 7 | |
751 | (@value{GDBP}) @b{p len_rquote=strlen(rquote)} | |
752 | $6 = 9 | |
753 | @end smallexample | |
754 | ||
755 | @noindent | |
756 | Is that enough to fix the problem of using the new quotes with the | |
757 | @code{m4} built-in @code{defn}? We can allow @code{m4} to continue | |
758 | executing with the @code{c} (@code{continue}) command, and then try the | |
759 | example that caused trouble initially: | |
760 | ||
761 | @smallexample | |
762 | (@value{GDBP}) @b{c} | |
763 | Continuing. | |
764 | ||
765 | @b{define(baz,defn(<QUOTE>foo<UNQUOTE>))} | |
766 | ||
767 | baz | |
768 | 0000 | |
769 | @end smallexample | |
770 | ||
771 | @noindent | |
772 | Success! The new quotes now work just as well as the default ones. The | |
773 | problem seems to have been just the two typos defining the wrong | |
774 | lengths. We allow @code{m4} exit by giving it an EOF as input: | |
775 | ||
776 | @smallexample | |
c8aa23ab | 777 | @b{Ctrl-d} |
c906108c SS |
778 | Program exited normally. |
779 | @end smallexample | |
780 | ||
781 | @noindent | |
782 | The message @samp{Program exited normally.} is from @value{GDBN}; it | |
783 | indicates @code{m4} has finished executing. We can end our @value{GDBN} | |
784 | session with the @value{GDBN} @code{quit} command. | |
785 | ||
786 | @smallexample | |
787 | (@value{GDBP}) @b{quit} | |
788 | @end smallexample | |
c906108c | 789 | |
6d2ebf8b | 790 | @node Invocation |
c906108c SS |
791 | @chapter Getting In and Out of @value{GDBN} |
792 | ||
793 | This chapter discusses how to start @value{GDBN}, and how to get out of it. | |
5d161b24 | 794 | The essentials are: |
c906108c | 795 | @itemize @bullet |
5d161b24 | 796 | @item |
53a5351d | 797 | type @samp{@value{GDBP}} to start @value{GDBN}. |
5d161b24 | 798 | @item |
c8aa23ab | 799 | type @kbd{quit} or @kbd{Ctrl-d} to exit. |
c906108c SS |
800 | @end itemize |
801 | ||
802 | @menu | |
803 | * Invoking GDB:: How to start @value{GDBN} | |
804 | * Quitting GDB:: How to quit @value{GDBN} | |
805 | * Shell Commands:: How to use shell commands inside @value{GDBN} | |
79a6e687 | 806 | * Logging Output:: How to log @value{GDBN}'s output to a file |
c906108c SS |
807 | @end menu |
808 | ||
6d2ebf8b | 809 | @node Invoking GDB |
c906108c SS |
810 | @section Invoking @value{GDBN} |
811 | ||
c906108c SS |
812 | Invoke @value{GDBN} by running the program @code{@value{GDBP}}. Once started, |
813 | @value{GDBN} reads commands from the terminal until you tell it to exit. | |
814 | ||
815 | You can also run @code{@value{GDBP}} with a variety of arguments and options, | |
816 | to specify more of your debugging environment at the outset. | |
817 | ||
c906108c SS |
818 | The command-line options described here are designed |
819 | to cover a variety of situations; in some environments, some of these | |
5d161b24 | 820 | options may effectively be unavailable. |
c906108c SS |
821 | |
822 | The most usual way to start @value{GDBN} is with one argument, | |
823 | specifying an executable program: | |
824 | ||
474c8240 | 825 | @smallexample |
c906108c | 826 | @value{GDBP} @var{program} |
474c8240 | 827 | @end smallexample |
c906108c | 828 | |
c906108c SS |
829 | @noindent |
830 | You can also start with both an executable program and a core file | |
831 | specified: | |
832 | ||
474c8240 | 833 | @smallexample |
c906108c | 834 | @value{GDBP} @var{program} @var{core} |
474c8240 | 835 | @end smallexample |
c906108c SS |
836 | |
837 | You can, instead, specify a process ID as a second argument, if you want | |
838 | to debug a running process: | |
839 | ||
474c8240 | 840 | @smallexample |
c906108c | 841 | @value{GDBP} @var{program} 1234 |
474c8240 | 842 | @end smallexample |
c906108c SS |
843 | |
844 | @noindent | |
845 | would attach @value{GDBN} to process @code{1234} (unless you also have a file | |
846 | named @file{1234}; @value{GDBN} does check for a core file first). | |
847 | ||
c906108c | 848 | Taking advantage of the second command-line argument requires a fairly |
2df3850c JM |
849 | complete operating system; when you use @value{GDBN} as a remote |
850 | debugger attached to a bare board, there may not be any notion of | |
851 | ``process'', and there is often no way to get a core dump. @value{GDBN} | |
852 | will warn you if it is unable to attach or to read core dumps. | |
c906108c | 853 | |
aa26fa3a TT |
854 | You can optionally have @code{@value{GDBP}} pass any arguments after the |
855 | executable file to the inferior using @code{--args}. This option stops | |
856 | option processing. | |
474c8240 | 857 | @smallexample |
3f94c067 | 858 | @value{GDBP} --args gcc -O2 -c foo.c |
474c8240 | 859 | @end smallexample |
aa26fa3a TT |
860 | This will cause @code{@value{GDBP}} to debug @code{gcc}, and to set |
861 | @code{gcc}'s command-line arguments (@pxref{Arguments}) to @samp{-O2 -c foo.c}. | |
862 | ||
96a2c332 | 863 | You can run @code{@value{GDBP}} without printing the front material, which describes |
c906108c SS |
864 | @value{GDBN}'s non-warranty, by specifying @code{-silent}: |
865 | ||
866 | @smallexample | |
867 | @value{GDBP} -silent | |
868 | @end smallexample | |
869 | ||
870 | @noindent | |
871 | You can further control how @value{GDBN} starts up by using command-line | |
872 | options. @value{GDBN} itself can remind you of the options available. | |
873 | ||
874 | @noindent | |
875 | Type | |
876 | ||
474c8240 | 877 | @smallexample |
c906108c | 878 | @value{GDBP} -help |
474c8240 | 879 | @end smallexample |
c906108c SS |
880 | |
881 | @noindent | |
882 | to display all available options and briefly describe their use | |
883 | (@samp{@value{GDBP} -h} is a shorter equivalent). | |
884 | ||
885 | All options and command line arguments you give are processed | |
886 | in sequential order. The order makes a difference when the | |
887 | @samp{-x} option is used. | |
888 | ||
889 | ||
890 | @menu | |
c906108c SS |
891 | * File Options:: Choosing files |
892 | * Mode Options:: Choosing modes | |
6fc08d32 | 893 | * Startup:: What @value{GDBN} does during startup |
c906108c SS |
894 | @end menu |
895 | ||
6d2ebf8b | 896 | @node File Options |
79a6e687 | 897 | @subsection Choosing Files |
c906108c | 898 | |
2df3850c | 899 | When @value{GDBN} starts, it reads any arguments other than options as |
c906108c SS |
900 | specifying an executable file and core file (or process ID). This is |
901 | the same as if the arguments were specified by the @samp{-se} and | |
d52fb0e9 | 902 | @samp{-c} (or @samp{-p}) options respectively. (@value{GDBN} reads the |
19837790 MS |
903 | first argument that does not have an associated option flag as |
904 | equivalent to the @samp{-se} option followed by that argument; and the | |
905 | second argument that does not have an associated option flag, if any, as | |
906 | equivalent to the @samp{-c}/@samp{-p} option followed by that argument.) | |
907 | If the second argument begins with a decimal digit, @value{GDBN} will | |
908 | first attempt to attach to it as a process, and if that fails, attempt | |
909 | to open it as a corefile. If you have a corefile whose name begins with | |
b383017d | 910 | a digit, you can prevent @value{GDBN} from treating it as a pid by |
c1468174 | 911 | prefixing it with @file{./}, e.g.@: @file{./12345}. |
7a292a7a SS |
912 | |
913 | If @value{GDBN} has not been configured to included core file support, | |
914 | such as for most embedded targets, then it will complain about a second | |
915 | argument and ignore it. | |
c906108c SS |
916 | |
917 | Many options have both long and short forms; both are shown in the | |
918 | following list. @value{GDBN} also recognizes the long forms if you truncate | |
919 | them, so long as enough of the option is present to be unambiguous. | |
920 | (If you prefer, you can flag option arguments with @samp{--} rather | |
921 | than @samp{-}, though we illustrate the more usual convention.) | |
922 | ||
d700128c EZ |
923 | @c NOTE: the @cindex entries here use double dashes ON PURPOSE. This |
924 | @c way, both those who look for -foo and --foo in the index, will find | |
925 | @c it. | |
926 | ||
c906108c SS |
927 | @table @code |
928 | @item -symbols @var{file} | |
929 | @itemx -s @var{file} | |
d700128c EZ |
930 | @cindex @code{--symbols} |
931 | @cindex @code{-s} | |
c906108c SS |
932 | Read symbol table from file @var{file}. |
933 | ||
934 | @item -exec @var{file} | |
935 | @itemx -e @var{file} | |
d700128c EZ |
936 | @cindex @code{--exec} |
937 | @cindex @code{-e} | |
7a292a7a SS |
938 | Use file @var{file} as the executable file to execute when appropriate, |
939 | and for examining pure data in conjunction with a core dump. | |
c906108c SS |
940 | |
941 | @item -se @var{file} | |
d700128c | 942 | @cindex @code{--se} |
c906108c SS |
943 | Read symbol table from file @var{file} and use it as the executable |
944 | file. | |
945 | ||
c906108c SS |
946 | @item -core @var{file} |
947 | @itemx -c @var{file} | |
d700128c EZ |
948 | @cindex @code{--core} |
949 | @cindex @code{-c} | |
b383017d | 950 | Use file @var{file} as a core dump to examine. |
c906108c | 951 | |
19837790 MS |
952 | @item -pid @var{number} |
953 | @itemx -p @var{number} | |
954 | @cindex @code{--pid} | |
955 | @cindex @code{-p} | |
956 | Connect to process ID @var{number}, as with the @code{attach} command. | |
c906108c SS |
957 | |
958 | @item -command @var{file} | |
959 | @itemx -x @var{file} | |
d700128c EZ |
960 | @cindex @code{--command} |
961 | @cindex @code{-x} | |
c906108c SS |
962 | Execute @value{GDBN} commands from file @var{file}. @xref{Command |
963 | Files,, Command files}. | |
964 | ||
8a5a3c82 AS |
965 | @item -eval-command @var{command} |
966 | @itemx -ex @var{command} | |
967 | @cindex @code{--eval-command} | |
968 | @cindex @code{-ex} | |
969 | Execute a single @value{GDBN} command. | |
970 | ||
971 | This option may be used multiple times to call multiple commands. It may | |
972 | also be interleaved with @samp{-command} as required. | |
973 | ||
974 | @smallexample | |
975 | @value{GDBP} -ex 'target sim' -ex 'load' \ | |
976 | -x setbreakpoints -ex 'run' a.out | |
977 | @end smallexample | |
978 | ||
c906108c SS |
979 | @item -directory @var{directory} |
980 | @itemx -d @var{directory} | |
d700128c EZ |
981 | @cindex @code{--directory} |
982 | @cindex @code{-d} | |
4b505b12 | 983 | Add @var{directory} to the path to search for source and script files. |
c906108c | 984 | |
c906108c SS |
985 | @item -r |
986 | @itemx -readnow | |
d700128c EZ |
987 | @cindex @code{--readnow} |
988 | @cindex @code{-r} | |
c906108c SS |
989 | Read each symbol file's entire symbol table immediately, rather than |
990 | the default, which is to read it incrementally as it is needed. | |
991 | This makes startup slower, but makes future operations faster. | |
53a5351d | 992 | |
c906108c SS |
993 | @end table |
994 | ||
6d2ebf8b | 995 | @node Mode Options |
79a6e687 | 996 | @subsection Choosing Modes |
c906108c SS |
997 | |
998 | You can run @value{GDBN} in various alternative modes---for example, in | |
999 | batch mode or quiet mode. | |
1000 | ||
1001 | @table @code | |
1002 | @item -nx | |
1003 | @itemx -n | |
d700128c EZ |
1004 | @cindex @code{--nx} |
1005 | @cindex @code{-n} | |
96565e91 | 1006 | Do not execute commands found in any initialization files. Normally, |
2df3850c JM |
1007 | @value{GDBN} executes the commands in these files after all the command |
1008 | options and arguments have been processed. @xref{Command Files,,Command | |
79a6e687 | 1009 | Files}. |
c906108c SS |
1010 | |
1011 | @item -quiet | |
d700128c | 1012 | @itemx -silent |
c906108c | 1013 | @itemx -q |
d700128c EZ |
1014 | @cindex @code{--quiet} |
1015 | @cindex @code{--silent} | |
1016 | @cindex @code{-q} | |
c906108c SS |
1017 | ``Quiet''. Do not print the introductory and copyright messages. These |
1018 | messages are also suppressed in batch mode. | |
1019 | ||
1020 | @item -batch | |
d700128c | 1021 | @cindex @code{--batch} |
c906108c SS |
1022 | Run in batch mode. Exit with status @code{0} after processing all the |
1023 | command files specified with @samp{-x} (and all commands from | |
1024 | initialization files, if not inhibited with @samp{-n}). Exit with | |
1025 | nonzero status if an error occurs in executing the @value{GDBN} commands | |
1026 | in the command files. | |
1027 | ||
2df3850c JM |
1028 | Batch mode may be useful for running @value{GDBN} as a filter, for |
1029 | example to download and run a program on another computer; in order to | |
1030 | make this more useful, the message | |
c906108c | 1031 | |
474c8240 | 1032 | @smallexample |
c906108c | 1033 | Program exited normally. |
474c8240 | 1034 | @end smallexample |
c906108c SS |
1035 | |
1036 | @noindent | |
2df3850c JM |
1037 | (which is ordinarily issued whenever a program running under |
1038 | @value{GDBN} control terminates) is not issued when running in batch | |
1039 | mode. | |
1040 | ||
1a088d06 AS |
1041 | @item -batch-silent |
1042 | @cindex @code{--batch-silent} | |
1043 | Run in batch mode exactly like @samp{-batch}, but totally silently. All | |
1044 | @value{GDBN} output to @code{stdout} is prevented (@code{stderr} is | |
1045 | unaffected). This is much quieter than @samp{-silent} and would be useless | |
1046 | for an interactive session. | |
1047 | ||
1048 | This is particularly useful when using targets that give @samp{Loading section} | |
1049 | messages, for example. | |
1050 | ||
1051 | Note that targets that give their output via @value{GDBN}, as opposed to | |
1052 | writing directly to @code{stdout}, will also be made silent. | |
1053 | ||
4b0ad762 AS |
1054 | @item -return-child-result |
1055 | @cindex @code{--return-child-result} | |
1056 | The return code from @value{GDBN} will be the return code from the child | |
1057 | process (the process being debugged), with the following exceptions: | |
1058 | ||
1059 | @itemize @bullet | |
1060 | @item | |
1061 | @value{GDBN} exits abnormally. E.g., due to an incorrect argument or an | |
1062 | internal error. In this case the exit code is the same as it would have been | |
1063 | without @samp{-return-child-result}. | |
1064 | @item | |
1065 | The user quits with an explicit value. E.g., @samp{quit 1}. | |
1066 | @item | |
1067 | The child process never runs, or is not allowed to terminate, in which case | |
1068 | the exit code will be -1. | |
1069 | @end itemize | |
1070 | ||
1071 | This option is useful in conjunction with @samp{-batch} or @samp{-batch-silent}, | |
1072 | when @value{GDBN} is being used as a remote program loader or simulator | |
1073 | interface. | |
1074 | ||
2df3850c JM |
1075 | @item -nowindows |
1076 | @itemx -nw | |
d700128c EZ |
1077 | @cindex @code{--nowindows} |
1078 | @cindex @code{-nw} | |
2df3850c | 1079 | ``No windows''. If @value{GDBN} comes with a graphical user interface |
96a2c332 | 1080 | (GUI) built in, then this option tells @value{GDBN} to only use the command-line |
2df3850c JM |
1081 | interface. If no GUI is available, this option has no effect. |
1082 | ||
1083 | @item -windows | |
1084 | @itemx -w | |
d700128c EZ |
1085 | @cindex @code{--windows} |
1086 | @cindex @code{-w} | |
2df3850c JM |
1087 | If @value{GDBN} includes a GUI, then this option requires it to be |
1088 | used if possible. | |
c906108c SS |
1089 | |
1090 | @item -cd @var{directory} | |
d700128c | 1091 | @cindex @code{--cd} |
c906108c SS |
1092 | Run @value{GDBN} using @var{directory} as its working directory, |
1093 | instead of the current directory. | |
1094 | ||
c906108c SS |
1095 | @item -fullname |
1096 | @itemx -f | |
d700128c EZ |
1097 | @cindex @code{--fullname} |
1098 | @cindex @code{-f} | |
7a292a7a SS |
1099 | @sc{gnu} Emacs sets this option when it runs @value{GDBN} as a |
1100 | subprocess. It tells @value{GDBN} to output the full file name and line | |
1101 | number in a standard, recognizable fashion each time a stack frame is | |
1102 | displayed (which includes each time your program stops). This | |
1103 | recognizable format looks like two @samp{\032} characters, followed by | |
1104 | the file name, line number and character position separated by colons, | |
1105 | and a newline. The Emacs-to-@value{GDBN} interface program uses the two | |
1106 | @samp{\032} characters as a signal to display the source code for the | |
1107 | frame. | |
c906108c | 1108 | |
d700128c EZ |
1109 | @item -epoch |
1110 | @cindex @code{--epoch} | |
1111 | The Epoch Emacs-@value{GDBN} interface sets this option when it runs | |
1112 | @value{GDBN} as a subprocess. It tells @value{GDBN} to modify its print | |
1113 | routines so as to allow Epoch to display values of expressions in a | |
1114 | separate window. | |
1115 | ||
1116 | @item -annotate @var{level} | |
1117 | @cindex @code{--annotate} | |
1118 | This option sets the @dfn{annotation level} inside @value{GDBN}. Its | |
1119 | effect is identical to using @samp{set annotate @var{level}} | |
086432e2 AC |
1120 | (@pxref{Annotations}). The annotation @var{level} controls how much |
1121 | information @value{GDBN} prints together with its prompt, values of | |
1122 | expressions, source lines, and other types of output. Level 0 is the | |
1123 | normal, level 1 is for use when @value{GDBN} is run as a subprocess of | |
1124 | @sc{gnu} Emacs, level 3 is the maximum annotation suitable for programs | |
1125 | that control @value{GDBN}, and level 2 has been deprecated. | |
1126 | ||
265eeb58 | 1127 | The annotation mechanism has largely been superseded by @sc{gdb/mi} |
086432e2 | 1128 | (@pxref{GDB/MI}). |
d700128c | 1129 | |
aa26fa3a TT |
1130 | @item --args |
1131 | @cindex @code{--args} | |
1132 | Change interpretation of command line so that arguments following the | |
1133 | executable file are passed as command line arguments to the inferior. | |
1134 | This option stops option processing. | |
1135 | ||
2df3850c JM |
1136 | @item -baud @var{bps} |
1137 | @itemx -b @var{bps} | |
d700128c EZ |
1138 | @cindex @code{--baud} |
1139 | @cindex @code{-b} | |
c906108c SS |
1140 | Set the line speed (baud rate or bits per second) of any serial |
1141 | interface used by @value{GDBN} for remote debugging. | |
c906108c | 1142 | |
f47b1503 AS |
1143 | @item -l @var{timeout} |
1144 | @cindex @code{-l} | |
1145 | Set the timeout (in seconds) of any communication used by @value{GDBN} | |
1146 | for remote debugging. | |
1147 | ||
c906108c | 1148 | @item -tty @var{device} |
d700128c EZ |
1149 | @itemx -t @var{device} |
1150 | @cindex @code{--tty} | |
1151 | @cindex @code{-t} | |
c906108c SS |
1152 | Run using @var{device} for your program's standard input and output. |
1153 | @c FIXME: kingdon thinks there is more to -tty. Investigate. | |
c906108c | 1154 | |
53a5351d | 1155 | @c resolve the situation of these eventually |
c4555f82 SC |
1156 | @item -tui |
1157 | @cindex @code{--tui} | |
d0d5df6f AC |
1158 | Activate the @dfn{Text User Interface} when starting. The Text User |
1159 | Interface manages several text windows on the terminal, showing | |
1160 | source, assembly, registers and @value{GDBN} command outputs | |
1161 | (@pxref{TUI, ,@value{GDBN} Text User Interface}). Alternatively, the | |
1162 | Text User Interface can be enabled by invoking the program | |
46ba6afa | 1163 | @samp{@value{GDBTUI}}. Do not use this option if you run @value{GDBN} from |
d0d5df6f | 1164 | Emacs (@pxref{Emacs, ,Using @value{GDBN} under @sc{gnu} Emacs}). |
53a5351d JM |
1165 | |
1166 | @c @item -xdb | |
d700128c | 1167 | @c @cindex @code{--xdb} |
53a5351d JM |
1168 | @c Run in XDB compatibility mode, allowing the use of certain XDB commands. |
1169 | @c For information, see the file @file{xdb_trans.html}, which is usually | |
1170 | @c installed in the directory @code{/opt/langtools/wdb/doc} on HP-UX | |
1171 | @c systems. | |
1172 | ||
d700128c EZ |
1173 | @item -interpreter @var{interp} |
1174 | @cindex @code{--interpreter} | |
1175 | Use the interpreter @var{interp} for interface with the controlling | |
1176 | program or device. This option is meant to be set by programs which | |
94bbb2c0 | 1177 | communicate with @value{GDBN} using it as a back end. |
21c294e6 | 1178 | @xref{Interpreters, , Command Interpreters}. |
94bbb2c0 | 1179 | |
da0f9dcd | 1180 | @samp{--interpreter=mi} (or @samp{--interpreter=mi2}) causes |
2fcf52f0 | 1181 | @value{GDBN} to use the @dfn{@sc{gdb/mi} interface} (@pxref{GDB/MI, , |
6b5e8c01 | 1182 | The @sc{gdb/mi} Interface}) included since @value{GDBN} version 6.0. The |
6c74ac8b AC |
1183 | previous @sc{gdb/mi} interface, included in @value{GDBN} version 5.3 and |
1184 | selected with @samp{--interpreter=mi1}, is deprecated. Earlier | |
1185 | @sc{gdb/mi} interfaces are no longer supported. | |
d700128c EZ |
1186 | |
1187 | @item -write | |
1188 | @cindex @code{--write} | |
1189 | Open the executable and core files for both reading and writing. This | |
1190 | is equivalent to the @samp{set write on} command inside @value{GDBN} | |
1191 | (@pxref{Patching}). | |
1192 | ||
1193 | @item -statistics | |
1194 | @cindex @code{--statistics} | |
1195 | This option causes @value{GDBN} to print statistics about time and | |
1196 | memory usage after it completes each command and returns to the prompt. | |
1197 | ||
1198 | @item -version | |
1199 | @cindex @code{--version} | |
1200 | This option causes @value{GDBN} to print its version number and | |
1201 | no-warranty blurb, and exit. | |
1202 | ||
c906108c SS |
1203 | @end table |
1204 | ||
6fc08d32 | 1205 | @node Startup |
79a6e687 | 1206 | @subsection What @value{GDBN} Does During Startup |
6fc08d32 EZ |
1207 | @cindex @value{GDBN} startup |
1208 | ||
1209 | Here's the description of what @value{GDBN} does during session startup: | |
1210 | ||
1211 | @enumerate | |
1212 | @item | |
1213 | Sets up the command interpreter as specified by the command line | |
1214 | (@pxref{Mode Options, interpreter}). | |
1215 | ||
1216 | @item | |
1217 | @cindex init file | |
098b41a6 JG |
1218 | Reads the system-wide @dfn{init file} (if @option{--with-system-gdbinit} was |
1219 | used when building @value{GDBN}; @pxref{System-wide configuration, | |
1220 | ,System-wide configuration and settings}) and executes all the commands in | |
1221 | that file. | |
1222 | ||
1223 | @item | |
1224 | Reads the init file (if any) in your home directory@footnote{On | |
6fc08d32 EZ |
1225 | DOS/Windows systems, the home directory is the one pointed to by the |
1226 | @code{HOME} environment variable.} and executes all the commands in | |
1227 | that file. | |
1228 | ||
1229 | @item | |
1230 | Processes command line options and operands. | |
1231 | ||
1232 | @item | |
1233 | Reads and executes the commands from init file (if any) in the current | |
119b882a EZ |
1234 | working directory. This is only done if the current directory is |
1235 | different from your home directory. Thus, you can have more than one | |
1236 | init file, one generic in your home directory, and another, specific | |
1237 | to the program you are debugging, in the directory where you invoke | |
6fc08d32 EZ |
1238 | @value{GDBN}. |
1239 | ||
1240 | @item | |
1241 | Reads command files specified by the @samp{-x} option. @xref{Command | |
1242 | Files}, for more details about @value{GDBN} command files. | |
1243 | ||
1244 | @item | |
1245 | Reads the command history recorded in the @dfn{history file}. | |
d620b259 | 1246 | @xref{Command History}, for more details about the command history and the |
6fc08d32 EZ |
1247 | files where @value{GDBN} records it. |
1248 | @end enumerate | |
1249 | ||
1250 | Init files use the same syntax as @dfn{command files} (@pxref{Command | |
1251 | Files}) and are processed by @value{GDBN} in the same way. The init | |
1252 | file in your home directory can set options (such as @samp{set | |
1253 | complaints}) that affect subsequent processing of command line options | |
1254 | and operands. Init files are not executed if you use the @samp{-nx} | |
79a6e687 | 1255 | option (@pxref{Mode Options, ,Choosing Modes}). |
6fc08d32 | 1256 | |
098b41a6 JG |
1257 | To display the list of init files loaded by gdb at startup, you |
1258 | can use @kbd{gdb --help}. | |
1259 | ||
6fc08d32 EZ |
1260 | @cindex init file name |
1261 | @cindex @file{.gdbinit} | |
119b882a | 1262 | @cindex @file{gdb.ini} |
8807d78b | 1263 | The @value{GDBN} init files are normally called @file{.gdbinit}. |
119b882a EZ |
1264 | The DJGPP port of @value{GDBN} uses the name @file{gdb.ini}, due to |
1265 | the limitations of file names imposed by DOS filesystems. The Windows | |
1266 | ports of @value{GDBN} use the standard name, but if they find a | |
1267 | @file{gdb.ini} file, they warn you about that and suggest to rename | |
1268 | the file to the standard name. | |
1269 | ||
6fc08d32 | 1270 | |
6d2ebf8b | 1271 | @node Quitting GDB |
c906108c SS |
1272 | @section Quitting @value{GDBN} |
1273 | @cindex exiting @value{GDBN} | |
1274 | @cindex leaving @value{GDBN} | |
1275 | ||
1276 | @table @code | |
1277 | @kindex quit @r{[}@var{expression}@r{]} | |
41afff9a | 1278 | @kindex q @r{(@code{quit})} |
96a2c332 SS |
1279 | @item quit @r{[}@var{expression}@r{]} |
1280 | @itemx q | |
1281 | To exit @value{GDBN}, use the @code{quit} command (abbreviated | |
c8aa23ab | 1282 | @code{q}), or type an end-of-file character (usually @kbd{Ctrl-d}). If you |
96a2c332 SS |
1283 | do not supply @var{expression}, @value{GDBN} will terminate normally; |
1284 | otherwise it will terminate using the result of @var{expression} as the | |
1285 | error code. | |
c906108c SS |
1286 | @end table |
1287 | ||
1288 | @cindex interrupt | |
c8aa23ab | 1289 | An interrupt (often @kbd{Ctrl-c}) does not exit from @value{GDBN}, but rather |
c906108c SS |
1290 | terminates the action of any @value{GDBN} command that is in progress and |
1291 | returns to @value{GDBN} command level. It is safe to type the interrupt | |
1292 | character at any time because @value{GDBN} does not allow it to take effect | |
1293 | until a time when it is safe. | |
1294 | ||
c906108c SS |
1295 | If you have been using @value{GDBN} to control an attached process or |
1296 | device, you can release it with the @code{detach} command | |
79a6e687 | 1297 | (@pxref{Attach, ,Debugging an Already-running Process}). |
c906108c | 1298 | |
6d2ebf8b | 1299 | @node Shell Commands |
79a6e687 | 1300 | @section Shell Commands |
c906108c SS |
1301 | |
1302 | If you need to execute occasional shell commands during your | |
1303 | debugging session, there is no need to leave or suspend @value{GDBN}; you can | |
1304 | just use the @code{shell} command. | |
1305 | ||
1306 | @table @code | |
1307 | @kindex shell | |
1308 | @cindex shell escape | |
1309 | @item shell @var{command string} | |
1310 | Invoke a standard shell to execute @var{command string}. | |
c906108c | 1311 | If it exists, the environment variable @code{SHELL} determines which |
d4f3574e SS |
1312 | shell to run. Otherwise @value{GDBN} uses the default shell |
1313 | (@file{/bin/sh} on Unix systems, @file{COMMAND.COM} on MS-DOS, etc.). | |
c906108c SS |
1314 | @end table |
1315 | ||
1316 | The utility @code{make} is often needed in development environments. | |
1317 | You do not have to use the @code{shell} command for this purpose in | |
1318 | @value{GDBN}: | |
1319 | ||
1320 | @table @code | |
1321 | @kindex make | |
1322 | @cindex calling make | |
1323 | @item make @var{make-args} | |
1324 | Execute the @code{make} program with the specified | |
1325 | arguments. This is equivalent to @samp{shell make @var{make-args}}. | |
1326 | @end table | |
1327 | ||
79a6e687 BW |
1328 | @node Logging Output |
1329 | @section Logging Output | |
0fac0b41 | 1330 | @cindex logging @value{GDBN} output |
9c16f35a | 1331 | @cindex save @value{GDBN} output to a file |
0fac0b41 DJ |
1332 | |
1333 | You may want to save the output of @value{GDBN} commands to a file. | |
1334 | There are several commands to control @value{GDBN}'s logging. | |
1335 | ||
1336 | @table @code | |
1337 | @kindex set logging | |
1338 | @item set logging on | |
1339 | Enable logging. | |
1340 | @item set logging off | |
1341 | Disable logging. | |
9c16f35a | 1342 | @cindex logging file name |
0fac0b41 DJ |
1343 | @item set logging file @var{file} |
1344 | Change the name of the current logfile. The default logfile is @file{gdb.txt}. | |
1345 | @item set logging overwrite [on|off] | |
1346 | By default, @value{GDBN} will append to the logfile. Set @code{overwrite} if | |
1347 | you want @code{set logging on} to overwrite the logfile instead. | |
1348 | @item set logging redirect [on|off] | |
1349 | By default, @value{GDBN} output will go to both the terminal and the logfile. | |
1350 | Set @code{redirect} if you want output to go only to the log file. | |
1351 | @kindex show logging | |
1352 | @item show logging | |
1353 | Show the current values of the logging settings. | |
1354 | @end table | |
1355 | ||
6d2ebf8b | 1356 | @node Commands |
c906108c SS |
1357 | @chapter @value{GDBN} Commands |
1358 | ||
1359 | You can abbreviate a @value{GDBN} command to the first few letters of the command | |
1360 | name, if that abbreviation is unambiguous; and you can repeat certain | |
1361 | @value{GDBN} commands by typing just @key{RET}. You can also use the @key{TAB} | |
1362 | key to get @value{GDBN} to fill out the rest of a word in a command (or to | |
1363 | show you the alternatives available, if there is more than one possibility). | |
1364 | ||
1365 | @menu | |
1366 | * Command Syntax:: How to give commands to @value{GDBN} | |
1367 | * Completion:: Command completion | |
1368 | * Help:: How to ask @value{GDBN} for help | |
1369 | @end menu | |
1370 | ||
6d2ebf8b | 1371 | @node Command Syntax |
79a6e687 | 1372 | @section Command Syntax |
c906108c SS |
1373 | |
1374 | A @value{GDBN} command is a single line of input. There is no limit on | |
1375 | how long it can be. It starts with a command name, which is followed by | |
1376 | arguments whose meaning depends on the command name. For example, the | |
1377 | command @code{step} accepts an argument which is the number of times to | |
1378 | step, as in @samp{step 5}. You can also use the @code{step} command | |
96a2c332 | 1379 | with no arguments. Some commands do not allow any arguments. |
c906108c SS |
1380 | |
1381 | @cindex abbreviation | |
1382 | @value{GDBN} command names may always be truncated if that abbreviation is | |
1383 | unambiguous. Other possible command abbreviations are listed in the | |
1384 | documentation for individual commands. In some cases, even ambiguous | |
1385 | abbreviations are allowed; for example, @code{s} is specially defined as | |
1386 | equivalent to @code{step} even though there are other commands whose | |
1387 | names start with @code{s}. You can test abbreviations by using them as | |
1388 | arguments to the @code{help} command. | |
1389 | ||
1390 | @cindex repeating commands | |
41afff9a | 1391 | @kindex RET @r{(repeat last command)} |
c906108c | 1392 | A blank line as input to @value{GDBN} (typing just @key{RET}) means to |
96a2c332 | 1393 | repeat the previous command. Certain commands (for example, @code{run}) |
c906108c SS |
1394 | will not repeat this way; these are commands whose unintentional |
1395 | repetition might cause trouble and which you are unlikely to want to | |
c45da7e6 EZ |
1396 | repeat. User-defined commands can disable this feature; see |
1397 | @ref{Define, dont-repeat}. | |
c906108c SS |
1398 | |
1399 | The @code{list} and @code{x} commands, when you repeat them with | |
1400 | @key{RET}, construct new arguments rather than repeating | |
1401 | exactly as typed. This permits easy scanning of source or memory. | |
1402 | ||
1403 | @value{GDBN} can also use @key{RET} in another way: to partition lengthy | |
1404 | output, in a way similar to the common utility @code{more} | |
79a6e687 | 1405 | (@pxref{Screen Size,,Screen Size}). Since it is easy to press one |
c906108c SS |
1406 | @key{RET} too many in this situation, @value{GDBN} disables command |
1407 | repetition after any command that generates this sort of display. | |
1408 | ||
41afff9a | 1409 | @kindex # @r{(a comment)} |
c906108c SS |
1410 | @cindex comment |
1411 | Any text from a @kbd{#} to the end of the line is a comment; it does | |
1412 | nothing. This is useful mainly in command files (@pxref{Command | |
79a6e687 | 1413 | Files,,Command Files}). |
c906108c | 1414 | |
88118b3a | 1415 | @cindex repeating command sequences |
c8aa23ab EZ |
1416 | @kindex Ctrl-o @r{(operate-and-get-next)} |
1417 | The @kbd{Ctrl-o} binding is useful for repeating a complex sequence of | |
7f9087cb | 1418 | commands. This command accepts the current line, like @key{RET}, and |
88118b3a TT |
1419 | then fetches the next line relative to the current line from the history |
1420 | for editing. | |
1421 | ||
6d2ebf8b | 1422 | @node Completion |
79a6e687 | 1423 | @section Command Completion |
c906108c SS |
1424 | |
1425 | @cindex completion | |
1426 | @cindex word completion | |
1427 | @value{GDBN} can fill in the rest of a word in a command for you, if there is | |
1428 | only one possibility; it can also show you what the valid possibilities | |
1429 | are for the next word in a command, at any time. This works for @value{GDBN} | |
1430 | commands, @value{GDBN} subcommands, and the names of symbols in your program. | |
1431 | ||
1432 | Press the @key{TAB} key whenever you want @value{GDBN} to fill out the rest | |
1433 | of a word. If there is only one possibility, @value{GDBN} fills in the | |
1434 | word, and waits for you to finish the command (or press @key{RET} to | |
1435 | enter it). For example, if you type | |
1436 | ||
1437 | @c FIXME "@key" does not distinguish its argument sufficiently to permit | |
1438 | @c complete accuracy in these examples; space introduced for clarity. | |
1439 | @c If texinfo enhancements make it unnecessary, it would be nice to | |
1440 | @c replace " @key" by "@key" in the following... | |
474c8240 | 1441 | @smallexample |
c906108c | 1442 | (@value{GDBP}) info bre @key{TAB} |
474c8240 | 1443 | @end smallexample |
c906108c SS |
1444 | |
1445 | @noindent | |
1446 | @value{GDBN} fills in the rest of the word @samp{breakpoints}, since that is | |
1447 | the only @code{info} subcommand beginning with @samp{bre}: | |
1448 | ||
474c8240 | 1449 | @smallexample |
c906108c | 1450 | (@value{GDBP}) info breakpoints |
474c8240 | 1451 | @end smallexample |
c906108c SS |
1452 | |
1453 | @noindent | |
1454 | You can either press @key{RET} at this point, to run the @code{info | |
1455 | breakpoints} command, or backspace and enter something else, if | |
1456 | @samp{breakpoints} does not look like the command you expected. (If you | |
1457 | were sure you wanted @code{info breakpoints} in the first place, you | |
1458 | might as well just type @key{RET} immediately after @samp{info bre}, | |
1459 | to exploit command abbreviations rather than command completion). | |
1460 | ||
1461 | If there is more than one possibility for the next word when you press | |
1462 | @key{TAB}, @value{GDBN} sounds a bell. You can either supply more | |
1463 | characters and try again, or just press @key{TAB} a second time; | |
1464 | @value{GDBN} displays all the possible completions for that word. For | |
1465 | example, you might want to set a breakpoint on a subroutine whose name | |
1466 | begins with @samp{make_}, but when you type @kbd{b make_@key{TAB}} @value{GDBN} | |
1467 | just sounds the bell. Typing @key{TAB} again displays all the | |
1468 | function names in your program that begin with those characters, for | |
1469 | example: | |
1470 | ||
474c8240 | 1471 | @smallexample |
c906108c SS |
1472 | (@value{GDBP}) b make_ @key{TAB} |
1473 | @exdent @value{GDBN} sounds bell; press @key{TAB} again, to see: | |
5d161b24 DB |
1474 | make_a_section_from_file make_environ |
1475 | make_abs_section make_function_type | |
1476 | make_blockvector make_pointer_type | |
1477 | make_cleanup make_reference_type | |
c906108c SS |
1478 | make_command make_symbol_completion_list |
1479 | (@value{GDBP}) b make_ | |
474c8240 | 1480 | @end smallexample |
c906108c SS |
1481 | |
1482 | @noindent | |
1483 | After displaying the available possibilities, @value{GDBN} copies your | |
1484 | partial input (@samp{b make_} in the example) so you can finish the | |
1485 | command. | |
1486 | ||
1487 | If you just want to see the list of alternatives in the first place, you | |
b37052ae | 1488 | can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?} |
7a292a7a | 1489 | means @kbd{@key{META} ?}. You can type this either by holding down a |
c906108c | 1490 | key designated as the @key{META} shift on your keyboard (if there is |
7a292a7a | 1491 | one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}. |
c906108c SS |
1492 | |
1493 | @cindex quotes in commands | |
1494 | @cindex completion of quoted strings | |
1495 | Sometimes the string you need, while logically a ``word'', may contain | |
7a292a7a SS |
1496 | parentheses or other characters that @value{GDBN} normally excludes from |
1497 | its notion of a word. To permit word completion to work in this | |
1498 | situation, you may enclose words in @code{'} (single quote marks) in | |
1499 | @value{GDBN} commands. | |
c906108c | 1500 | |
c906108c | 1501 | The most likely situation where you might need this is in typing the |
b37052ae EZ |
1502 | name of a C@t{++} function. This is because C@t{++} allows function |
1503 | overloading (multiple definitions of the same function, distinguished | |
1504 | by argument type). For example, when you want to set a breakpoint you | |
1505 | may need to distinguish whether you mean the version of @code{name} | |
1506 | that takes an @code{int} parameter, @code{name(int)}, or the version | |
1507 | that takes a @code{float} parameter, @code{name(float)}. To use the | |
1508 | word-completion facilities in this situation, type a single quote | |
1509 | @code{'} at the beginning of the function name. This alerts | |
1510 | @value{GDBN} that it may need to consider more information than usual | |
1511 | when you press @key{TAB} or @kbd{M-?} to request word completion: | |
c906108c | 1512 | |
474c8240 | 1513 | @smallexample |
96a2c332 | 1514 | (@value{GDBP}) b 'bubble( @kbd{M-?} |
c906108c SS |
1515 | bubble(double,double) bubble(int,int) |
1516 | (@value{GDBP}) b 'bubble( | |
474c8240 | 1517 | @end smallexample |
c906108c SS |
1518 | |
1519 | In some cases, @value{GDBN} can tell that completing a name requires using | |
1520 | quotes. When this happens, @value{GDBN} inserts the quote for you (while | |
1521 | completing as much as it can) if you do not type the quote in the first | |
1522 | place: | |
1523 | ||
474c8240 | 1524 | @smallexample |
c906108c SS |
1525 | (@value{GDBP}) b bub @key{TAB} |
1526 | @exdent @value{GDBN} alters your input line to the following, and rings a bell: | |
1527 | (@value{GDBP}) b 'bubble( | |
474c8240 | 1528 | @end smallexample |
c906108c SS |
1529 | |
1530 | @noindent | |
1531 | In general, @value{GDBN} can tell that a quote is needed (and inserts it) if | |
1532 | you have not yet started typing the argument list when you ask for | |
1533 | completion on an overloaded symbol. | |
1534 | ||
79a6e687 BW |
1535 | For more information about overloaded functions, see @ref{C Plus Plus |
1536 | Expressions, ,C@t{++} Expressions}. You can use the command @code{set | |
c906108c | 1537 | overload-resolution off} to disable overload resolution; |
79a6e687 | 1538 | see @ref{Debugging C Plus Plus, ,@value{GDBN} Features for C@t{++}}. |
c906108c | 1539 | |
65d12d83 TT |
1540 | @cindex completion of structure field names |
1541 | @cindex structure field name completion | |
1542 | @cindex completion of union field names | |
1543 | @cindex union field name completion | |
1544 | When completing in an expression which looks up a field in a | |
1545 | structure, @value{GDBN} also tries@footnote{The completer can be | |
1546 | confused by certain kinds of invalid expressions. Also, it only | |
1547 | examines the static type of the expression, not the dynamic type.} to | |
1548 | limit completions to the field names available in the type of the | |
1549 | left-hand-side: | |
1550 | ||
1551 | @smallexample | |
1552 | (@value{GDBP}) p gdb_stdout.@kbd{M-?} | |
1553 | magic to_delete to_fputs to_put to_rewind | |
1554 | to_data to_flush to_isatty to_read to_write | |
1555 | @end smallexample | |
1556 | ||
1557 | @noindent | |
1558 | This is because the @code{gdb_stdout} is a variable of the type | |
1559 | @code{struct ui_file} that is defined in @value{GDBN} sources as | |
1560 | follows: | |
1561 | ||
1562 | @smallexample | |
1563 | struct ui_file | |
1564 | @{ | |
1565 | int *magic; | |
1566 | ui_file_flush_ftype *to_flush; | |
1567 | ui_file_write_ftype *to_write; | |
1568 | ui_file_fputs_ftype *to_fputs; | |
1569 | ui_file_read_ftype *to_read; | |
1570 | ui_file_delete_ftype *to_delete; | |
1571 | ui_file_isatty_ftype *to_isatty; | |
1572 | ui_file_rewind_ftype *to_rewind; | |
1573 | ui_file_put_ftype *to_put; | |
1574 | void *to_data; | |
1575 | @} | |
1576 | @end smallexample | |
1577 | ||
c906108c | 1578 | |
6d2ebf8b | 1579 | @node Help |
79a6e687 | 1580 | @section Getting Help |
c906108c SS |
1581 | @cindex online documentation |
1582 | @kindex help | |
1583 | ||
5d161b24 | 1584 | You can always ask @value{GDBN} itself for information on its commands, |
c906108c SS |
1585 | using the command @code{help}. |
1586 | ||
1587 | @table @code | |
41afff9a | 1588 | @kindex h @r{(@code{help})} |
c906108c SS |
1589 | @item help |
1590 | @itemx h | |
1591 | You can use @code{help} (abbreviated @code{h}) with no arguments to | |
1592 | display a short list of named classes of commands: | |
1593 | ||
1594 | @smallexample | |
1595 | (@value{GDBP}) help | |
1596 | List of classes of commands: | |
1597 | ||
2df3850c | 1598 | aliases -- Aliases of other commands |
c906108c | 1599 | breakpoints -- Making program stop at certain points |
2df3850c | 1600 | data -- Examining data |
c906108c | 1601 | files -- Specifying and examining files |
2df3850c JM |
1602 | internals -- Maintenance commands |
1603 | obscure -- Obscure features | |
1604 | running -- Running the program | |
1605 | stack -- Examining the stack | |
c906108c SS |
1606 | status -- Status inquiries |
1607 | support -- Support facilities | |
12c27660 | 1608 | tracepoints -- Tracing of program execution without |
96a2c332 | 1609 | stopping the program |
c906108c | 1610 | user-defined -- User-defined commands |
c906108c | 1611 | |
5d161b24 | 1612 | Type "help" followed by a class name for a list of |
c906108c | 1613 | commands in that class. |
5d161b24 | 1614 | Type "help" followed by command name for full |
c906108c SS |
1615 | documentation. |
1616 | Command name abbreviations are allowed if unambiguous. | |
1617 | (@value{GDBP}) | |
1618 | @end smallexample | |
96a2c332 | 1619 | @c the above line break eliminates huge line overfull... |
c906108c SS |
1620 | |
1621 | @item help @var{class} | |
1622 | Using one of the general help classes as an argument, you can get a | |
1623 | list of the individual commands in that class. For example, here is the | |
1624 | help display for the class @code{status}: | |
1625 | ||
1626 | @smallexample | |
1627 | (@value{GDBP}) help status | |
1628 | Status inquiries. | |
1629 | ||
1630 | List of commands: | |
1631 | ||
1632 | @c Line break in "show" line falsifies real output, but needed | |
1633 | @c to fit in smallbook page size. | |
2df3850c | 1634 | info -- Generic command for showing things |
12c27660 | 1635 | about the program being debugged |
2df3850c | 1636 | show -- Generic command for showing things |
12c27660 | 1637 | about the debugger |
c906108c | 1638 | |
5d161b24 | 1639 | Type "help" followed by command name for full |
c906108c SS |
1640 | documentation. |
1641 | Command name abbreviations are allowed if unambiguous. | |
1642 | (@value{GDBP}) | |
1643 | @end smallexample | |
1644 | ||
1645 | @item help @var{command} | |
1646 | With a command name as @code{help} argument, @value{GDBN} displays a | |
1647 | short paragraph on how to use that command. | |
1648 | ||
6837a0a2 DB |
1649 | @kindex apropos |
1650 | @item apropos @var{args} | |
09d4efe1 | 1651 | The @code{apropos} command searches through all of the @value{GDBN} |
6837a0a2 | 1652 | commands, and their documentation, for the regular expression specified in |
99e008fe | 1653 | @var{args}. It prints out all matches found. For example: |
6837a0a2 DB |
1654 | |
1655 | @smallexample | |
1656 | apropos reload | |
1657 | @end smallexample | |
1658 | ||
b37052ae EZ |
1659 | @noindent |
1660 | results in: | |
6837a0a2 DB |
1661 | |
1662 | @smallexample | |
6d2ebf8b SS |
1663 | @c @group |
1664 | set symbol-reloading -- Set dynamic symbol table reloading | |
12c27660 | 1665 | multiple times in one run |
6d2ebf8b | 1666 | show symbol-reloading -- Show dynamic symbol table reloading |
12c27660 | 1667 | multiple times in one run |
6d2ebf8b | 1668 | @c @end group |
6837a0a2 DB |
1669 | @end smallexample |
1670 | ||
c906108c SS |
1671 | @kindex complete |
1672 | @item complete @var{args} | |
1673 | The @code{complete @var{args}} command lists all the possible completions | |
1674 | for the beginning of a command. Use @var{args} to specify the beginning of the | |
1675 | command you want completed. For example: | |
1676 | ||
1677 | @smallexample | |
1678 | complete i | |
1679 | @end smallexample | |
1680 | ||
1681 | @noindent results in: | |
1682 | ||
1683 | @smallexample | |
1684 | @group | |
2df3850c JM |
1685 | if |
1686 | ignore | |
c906108c SS |
1687 | info |
1688 | inspect | |
c906108c SS |
1689 | @end group |
1690 | @end smallexample | |
1691 | ||
1692 | @noindent This is intended for use by @sc{gnu} Emacs. | |
1693 | @end table | |
1694 | ||
1695 | In addition to @code{help}, you can use the @value{GDBN} commands @code{info} | |
1696 | and @code{show} to inquire about the state of your program, or the state | |
1697 | of @value{GDBN} itself. Each command supports many topics of inquiry; this | |
1698 | manual introduces each of them in the appropriate context. The listings | |
1699 | under @code{info} and under @code{show} in the Index point to | |
1700 | all the sub-commands. @xref{Index}. | |
1701 | ||
1702 | @c @group | |
1703 | @table @code | |
1704 | @kindex info | |
41afff9a | 1705 | @kindex i @r{(@code{info})} |
c906108c SS |
1706 | @item info |
1707 | This command (abbreviated @code{i}) is for describing the state of your | |
cda4ce5a | 1708 | program. For example, you can show the arguments passed to a function |
c906108c SS |
1709 | with @code{info args}, list the registers currently in use with @code{info |
1710 | registers}, or list the breakpoints you have set with @code{info breakpoints}. | |
1711 | You can get a complete list of the @code{info} sub-commands with | |
1712 | @w{@code{help info}}. | |
1713 | ||
1714 | @kindex set | |
1715 | @item set | |
5d161b24 | 1716 | You can assign the result of an expression to an environment variable with |
c906108c SS |
1717 | @code{set}. For example, you can set the @value{GDBN} prompt to a $-sign with |
1718 | @code{set prompt $}. | |
1719 | ||
1720 | @kindex show | |
1721 | @item show | |
5d161b24 | 1722 | In contrast to @code{info}, @code{show} is for describing the state of |
c906108c SS |
1723 | @value{GDBN} itself. |
1724 | You can change most of the things you can @code{show}, by using the | |
1725 | related command @code{set}; for example, you can control what number | |
1726 | system is used for displays with @code{set radix}, or simply inquire | |
1727 | which is currently in use with @code{show radix}. | |
1728 | ||
1729 | @kindex info set | |
1730 | To display all the settable parameters and their current | |
1731 | values, you can use @code{show} with no arguments; you may also use | |
1732 | @code{info set}. Both commands produce the same display. | |
1733 | @c FIXME: "info set" violates the rule that "info" is for state of | |
1734 | @c FIXME...program. Ck w/ GNU: "info set" to be called something else, | |
1735 | @c FIXME...or change desc of rule---eg "state of prog and debugging session"? | |
1736 | @end table | |
1737 | @c @end group | |
1738 | ||
1739 | Here are three miscellaneous @code{show} subcommands, all of which are | |
1740 | exceptional in lacking corresponding @code{set} commands: | |
1741 | ||
1742 | @table @code | |
1743 | @kindex show version | |
9c16f35a | 1744 | @cindex @value{GDBN} version number |
c906108c SS |
1745 | @item show version |
1746 | Show what version of @value{GDBN} is running. You should include this | |
2df3850c JM |
1747 | information in @value{GDBN} bug-reports. If multiple versions of |
1748 | @value{GDBN} are in use at your site, you may need to determine which | |
1749 | version of @value{GDBN} you are running; as @value{GDBN} evolves, new | |
1750 | commands are introduced, and old ones may wither away. Also, many | |
1751 | system vendors ship variant versions of @value{GDBN}, and there are | |
96a2c332 | 1752 | variant versions of @value{GDBN} in @sc{gnu}/Linux distributions as well. |
2df3850c JM |
1753 | The version number is the same as the one announced when you start |
1754 | @value{GDBN}. | |
c906108c SS |
1755 | |
1756 | @kindex show copying | |
09d4efe1 | 1757 | @kindex info copying |
9c16f35a | 1758 | @cindex display @value{GDBN} copyright |
c906108c | 1759 | @item show copying |
09d4efe1 | 1760 | @itemx info copying |
c906108c SS |
1761 | Display information about permission for copying @value{GDBN}. |
1762 | ||
1763 | @kindex show warranty | |
09d4efe1 | 1764 | @kindex info warranty |
c906108c | 1765 | @item show warranty |
09d4efe1 | 1766 | @itemx info warranty |
2df3850c | 1767 | Display the @sc{gnu} ``NO WARRANTY'' statement, or a warranty, |
96a2c332 | 1768 | if your version of @value{GDBN} comes with one. |
2df3850c | 1769 | |
c906108c SS |
1770 | @end table |
1771 | ||
6d2ebf8b | 1772 | @node Running |
c906108c SS |
1773 | @chapter Running Programs Under @value{GDBN} |
1774 | ||
1775 | When you run a program under @value{GDBN}, you must first generate | |
1776 | debugging information when you compile it. | |
7a292a7a SS |
1777 | |
1778 | You may start @value{GDBN} with its arguments, if any, in an environment | |
1779 | of your choice. If you are doing native debugging, you may redirect | |
1780 | your program's input and output, debug an already running process, or | |
1781 | kill a child process. | |
c906108c SS |
1782 | |
1783 | @menu | |
1784 | * Compilation:: Compiling for debugging | |
1785 | * Starting:: Starting your program | |
c906108c SS |
1786 | * Arguments:: Your program's arguments |
1787 | * Environment:: Your program's environment | |
c906108c SS |
1788 | |
1789 | * Working Directory:: Your program's working directory | |
1790 | * Input/Output:: Your program's input and output | |
1791 | * Attach:: Debugging an already-running process | |
1792 | * Kill Process:: Killing the child process | |
c906108c | 1793 | |
b77209e0 | 1794 | * Inferiors:: Debugging multiple inferiors |
c906108c SS |
1795 | * Threads:: Debugging programs with multiple threads |
1796 | * Processes:: Debugging programs with multiple processes | |
5c95884b | 1797 | * Checkpoint/Restart:: Setting a @emph{bookmark} to return to later |
c906108c SS |
1798 | @end menu |
1799 | ||
6d2ebf8b | 1800 | @node Compilation |
79a6e687 | 1801 | @section Compiling for Debugging |
c906108c SS |
1802 | |
1803 | In order to debug a program effectively, you need to generate | |
1804 | debugging information when you compile it. This debugging information | |
1805 | is stored in the object file; it describes the data type of each | |
1806 | variable or function and the correspondence between source line numbers | |
1807 | and addresses in the executable code. | |
1808 | ||
1809 | To request debugging information, specify the @samp{-g} option when you run | |
1810 | the compiler. | |
1811 | ||
514c4d71 | 1812 | Programs that are to be shipped to your customers are compiled with |
edb3359d | 1813 | optimizations, using the @samp{-O} compiler option. However, some |
514c4d71 EZ |
1814 | compilers are unable to handle the @samp{-g} and @samp{-O} options |
1815 | together. Using those compilers, you cannot generate optimized | |
c906108c SS |
1816 | executables containing debugging information. |
1817 | ||
514c4d71 | 1818 | @value{NGCC}, the @sc{gnu} C/C@t{++} compiler, supports @samp{-g} with or |
53a5351d JM |
1819 | without @samp{-O}, making it possible to debug optimized code. We |
1820 | recommend that you @emph{always} use @samp{-g} whenever you compile a | |
1821 | program. You may think your program is correct, but there is no sense | |
edb3359d | 1822 | in pushing your luck. For more information, see @ref{Optimized Code}. |
c906108c SS |
1823 | |
1824 | Older versions of the @sc{gnu} C compiler permitted a variant option | |
1825 | @w{@samp{-gg}} for debugging information. @value{GDBN} no longer supports this | |
1826 | format; if your @sc{gnu} C compiler has this option, do not use it. | |
1827 | ||
514c4d71 EZ |
1828 | @value{GDBN} knows about preprocessor macros and can show you their |
1829 | expansion (@pxref{Macros}). Most compilers do not include information | |
1830 | about preprocessor macros in the debugging information if you specify | |
1831 | the @option{-g} flag alone, because this information is rather large. | |
1832 | Version 3.1 and later of @value{NGCC}, the @sc{gnu} C compiler, | |
1833 | provides macro information if you specify the options | |
1834 | @option{-gdwarf-2} and @option{-g3}; the former option requests | |
1835 | debugging information in the Dwarf 2 format, and the latter requests | |
1836 | ``extra information''. In the future, we hope to find more compact | |
1837 | ways to represent macro information, so that it can be included with | |
1838 | @option{-g} alone. | |
1839 | ||
c906108c | 1840 | @need 2000 |
6d2ebf8b | 1841 | @node Starting |
79a6e687 | 1842 | @section Starting your Program |
c906108c SS |
1843 | @cindex starting |
1844 | @cindex running | |
1845 | ||
1846 | @table @code | |
1847 | @kindex run | |
41afff9a | 1848 | @kindex r @r{(@code{run})} |
c906108c SS |
1849 | @item run |
1850 | @itemx r | |
7a292a7a SS |
1851 | Use the @code{run} command to start your program under @value{GDBN}. |
1852 | You must first specify the program name (except on VxWorks) with an | |
1853 | argument to @value{GDBN} (@pxref{Invocation, ,Getting In and Out of | |
1854 | @value{GDBN}}), or by using the @code{file} or @code{exec-file} command | |
79a6e687 | 1855 | (@pxref{Files, ,Commands to Specify Files}). |
c906108c SS |
1856 | |
1857 | @end table | |
1858 | ||
c906108c SS |
1859 | If you are running your program in an execution environment that |
1860 | supports processes, @code{run} creates an inferior process and makes | |
8edfe269 DJ |
1861 | that process run your program. In some environments without processes, |
1862 | @code{run} jumps to the start of your program. Other targets, | |
1863 | like @samp{remote}, are always running. If you get an error | |
1864 | message like this one: | |
1865 | ||
1866 | @smallexample | |
1867 | The "remote" target does not support "run". | |
1868 | Try "help target" or "continue". | |
1869 | @end smallexample | |
1870 | ||
1871 | @noindent | |
1872 | then use @code{continue} to run your program. You may need @code{load} | |
1873 | first (@pxref{load}). | |
c906108c SS |
1874 | |
1875 | The execution of a program is affected by certain information it | |
1876 | receives from its superior. @value{GDBN} provides ways to specify this | |
1877 | information, which you must do @emph{before} starting your program. (You | |
1878 | can change it after starting your program, but such changes only affect | |
1879 | your program the next time you start it.) This information may be | |
1880 | divided into four categories: | |
1881 | ||
1882 | @table @asis | |
1883 | @item The @emph{arguments.} | |
1884 | Specify the arguments to give your program as the arguments of the | |
1885 | @code{run} command. If a shell is available on your target, the shell | |
1886 | is used to pass the arguments, so that you may use normal conventions | |
1887 | (such as wildcard expansion or variable substitution) in describing | |
1888 | the arguments. | |
1889 | In Unix systems, you can control which shell is used with the | |
1890 | @code{SHELL} environment variable. | |
79a6e687 | 1891 | @xref{Arguments, ,Your Program's Arguments}. |
c906108c SS |
1892 | |
1893 | @item The @emph{environment.} | |
1894 | Your program normally inherits its environment from @value{GDBN}, but you can | |
1895 | use the @value{GDBN} commands @code{set environment} and @code{unset | |
1896 | environment} to change parts of the environment that affect | |
79a6e687 | 1897 | your program. @xref{Environment, ,Your Program's Environment}. |
c906108c SS |
1898 | |
1899 | @item The @emph{working directory.} | |
1900 | Your program inherits its working directory from @value{GDBN}. You can set | |
1901 | the @value{GDBN} working directory with the @code{cd} command in @value{GDBN}. | |
79a6e687 | 1902 | @xref{Working Directory, ,Your Program's Working Directory}. |
c906108c SS |
1903 | |
1904 | @item The @emph{standard input and output.} | |
1905 | Your program normally uses the same device for standard input and | |
1906 | standard output as @value{GDBN} is using. You can redirect input and output | |
1907 | in the @code{run} command line, or you can use the @code{tty} command to | |
1908 | set a different device for your program. | |
79a6e687 | 1909 | @xref{Input/Output, ,Your Program's Input and Output}. |
c906108c SS |
1910 | |
1911 | @cindex pipes | |
1912 | @emph{Warning:} While input and output redirection work, you cannot use | |
1913 | pipes to pass the output of the program you are debugging to another | |
1914 | program; if you attempt this, @value{GDBN} is likely to wind up debugging the | |
1915 | wrong program. | |
1916 | @end table | |
c906108c SS |
1917 | |
1918 | When you issue the @code{run} command, your program begins to execute | |
79a6e687 | 1919 | immediately. @xref{Stopping, ,Stopping and Continuing}, for discussion |
c906108c SS |
1920 | of how to arrange for your program to stop. Once your program has |
1921 | stopped, you may call functions in your program, using the @code{print} | |
1922 | or @code{call} commands. @xref{Data, ,Examining Data}. | |
1923 | ||
1924 | If the modification time of your symbol file has changed since the last | |
1925 | time @value{GDBN} read its symbols, @value{GDBN} discards its symbol | |
1926 | table, and reads it again. When it does this, @value{GDBN} tries to retain | |
1927 | your current breakpoints. | |
1928 | ||
4e8b0763 JB |
1929 | @table @code |
1930 | @kindex start | |
1931 | @item start | |
1932 | @cindex run to main procedure | |
1933 | The name of the main procedure can vary from language to language. | |
1934 | With C or C@t{++}, the main procedure name is always @code{main}, but | |
1935 | other languages such as Ada do not require a specific name for their | |
1936 | main procedure. The debugger provides a convenient way to start the | |
1937 | execution of the program and to stop at the beginning of the main | |
1938 | procedure, depending on the language used. | |
1939 | ||
1940 | The @samp{start} command does the equivalent of setting a temporary | |
1941 | breakpoint at the beginning of the main procedure and then invoking | |
1942 | the @samp{run} command. | |
1943 | ||
f018e82f EZ |
1944 | @cindex elaboration phase |
1945 | Some programs contain an @dfn{elaboration} phase where some startup code is | |
1946 | executed before the main procedure is called. This depends on the | |
1947 | languages used to write your program. In C@t{++}, for instance, | |
4e8b0763 JB |
1948 | constructors for static and global objects are executed before |
1949 | @code{main} is called. It is therefore possible that the debugger stops | |
1950 | before reaching the main procedure. However, the temporary breakpoint | |
1951 | will remain to halt execution. | |
1952 | ||
1953 | Specify the arguments to give to your program as arguments to the | |
1954 | @samp{start} command. These arguments will be given verbatim to the | |
1955 | underlying @samp{run} command. Note that the same arguments will be | |
1956 | reused if no argument is provided during subsequent calls to | |
1957 | @samp{start} or @samp{run}. | |
1958 | ||
1959 | It is sometimes necessary to debug the program during elaboration. In | |
1960 | these cases, using the @code{start} command would stop the execution of | |
1961 | your program too late, as the program would have already completed the | |
1962 | elaboration phase. Under these circumstances, insert breakpoints in your | |
1963 | elaboration code before running your program. | |
ccd213ac DJ |
1964 | |
1965 | @kindex set exec-wrapper | |
1966 | @item set exec-wrapper @var{wrapper} | |
1967 | @itemx show exec-wrapper | |
1968 | @itemx unset exec-wrapper | |
1969 | When @samp{exec-wrapper} is set, the specified wrapper is used to | |
1970 | launch programs for debugging. @value{GDBN} starts your program | |
1971 | with a shell command of the form @kbd{exec @var{wrapper} | |
1972 | @var{program}}. Quoting is added to @var{program} and its | |
1973 | arguments, but not to @var{wrapper}, so you should add quotes if | |
1974 | appropriate for your shell. The wrapper runs until it executes | |
1975 | your program, and then @value{GDBN} takes control. | |
1976 | ||
1977 | You can use any program that eventually calls @code{execve} with | |
1978 | its arguments as a wrapper. Several standard Unix utilities do | |
1979 | this, e.g.@: @code{env} and @code{nohup}. Any Unix shell script ending | |
1980 | with @code{exec "$@@"} will also work. | |
1981 | ||
1982 | For example, you can use @code{env} to pass an environment variable to | |
1983 | the debugged program, without setting the variable in your shell's | |
1984 | environment: | |
1985 | ||
1986 | @smallexample | |
1987 | (@value{GDBP}) set exec-wrapper env 'LD_PRELOAD=libtest.so' | |
1988 | (@value{GDBP}) run | |
1989 | @end smallexample | |
1990 | ||
1991 | This command is available when debugging locally on most targets, excluding | |
1992 | @sc{djgpp}, Cygwin, MS Windows, and QNX Neutrino. | |
1993 | ||
10568435 JK |
1994 | @kindex set disable-randomization |
1995 | @item set disable-randomization | |
1996 | @itemx set disable-randomization on | |
1997 | This option (enabled by default in @value{GDBN}) will turn off the native | |
1998 | randomization of the virtual address space of the started program. This option | |
1999 | is useful for multiple debugging sessions to make the execution better | |
2000 | reproducible and memory addresses reusable across debugging sessions. | |
2001 | ||
2002 | This feature is implemented only on @sc{gnu}/Linux. You can get the same | |
2003 | behavior using | |
2004 | ||
2005 | @smallexample | |
2006 | (@value{GDBP}) set exec-wrapper setarch `uname -m` -R | |
2007 | @end smallexample | |
2008 | ||
2009 | @item set disable-randomization off | |
2010 | Leave the behavior of the started executable unchanged. Some bugs rear their | |
2011 | ugly heads only when the program is loaded at certain addresses. If your bug | |
2012 | disappears when you run the program under @value{GDBN}, that might be because | |
2013 | @value{GDBN} by default disables the address randomization on platforms, such | |
2014 | as @sc{gnu}/Linux, which do that for stand-alone programs. Use @kbd{set | |
2015 | disable-randomization off} to try to reproduce such elusive bugs. | |
2016 | ||
2017 | The virtual address space randomization is implemented only on @sc{gnu}/Linux. | |
2018 | It protects the programs against some kinds of security attacks. In these | |
2019 | cases the attacker needs to know the exact location of a concrete executable | |
2020 | code. Randomizing its location makes it impossible to inject jumps misusing | |
2021 | a code at its expected addresses. | |
2022 | ||
2023 | Prelinking shared libraries provides a startup performance advantage but it | |
2024 | makes addresses in these libraries predictable for privileged processes by | |
2025 | having just unprivileged access at the target system. Reading the shared | |
2026 | library binary gives enough information for assembling the malicious code | |
2027 | misusing it. Still even a prelinked shared library can get loaded at a new | |
2028 | random address just requiring the regular relocation process during the | |
2029 | startup. Shared libraries not already prelinked are always loaded at | |
2030 | a randomly chosen address. | |
2031 | ||
2032 | Position independent executables (PIE) contain position independent code | |
2033 | similar to the shared libraries and therefore such executables get loaded at | |
2034 | a randomly chosen address upon startup. PIE executables always load even | |
2035 | already prelinked shared libraries at a random address. You can build such | |
2036 | executable using @command{gcc -fPIE -pie}. | |
2037 | ||
2038 | Heap (malloc storage), stack and custom mmap areas are always placed randomly | |
2039 | (as long as the randomization is enabled). | |
2040 | ||
2041 | @item show disable-randomization | |
2042 | Show the current setting of the explicit disable of the native randomization of | |
2043 | the virtual address space of the started program. | |
2044 | ||
4e8b0763 JB |
2045 | @end table |
2046 | ||
6d2ebf8b | 2047 | @node Arguments |
79a6e687 | 2048 | @section Your Program's Arguments |
c906108c SS |
2049 | |
2050 | @cindex arguments (to your program) | |
2051 | The arguments to your program can be specified by the arguments of the | |
5d161b24 | 2052 | @code{run} command. |
c906108c SS |
2053 | They are passed to a shell, which expands wildcard characters and |
2054 | performs redirection of I/O, and thence to your program. Your | |
2055 | @code{SHELL} environment variable (if it exists) specifies what shell | |
2056 | @value{GDBN} uses. If you do not define @code{SHELL}, @value{GDBN} uses | |
d4f3574e SS |
2057 | the default shell (@file{/bin/sh} on Unix). |
2058 | ||
2059 | On non-Unix systems, the program is usually invoked directly by | |
2060 | @value{GDBN}, which emulates I/O redirection via the appropriate system | |
2061 | calls, and the wildcard characters are expanded by the startup code of | |
2062 | the program, not by the shell. | |
c906108c SS |
2063 | |
2064 | @code{run} with no arguments uses the same arguments used by the previous | |
2065 | @code{run}, or those set by the @code{set args} command. | |
2066 | ||
c906108c | 2067 | @table @code |
41afff9a | 2068 | @kindex set args |
c906108c SS |
2069 | @item set args |
2070 | Specify the arguments to be used the next time your program is run. If | |
2071 | @code{set args} has no arguments, @code{run} executes your program | |
2072 | with no arguments. Once you have run your program with arguments, | |
2073 | using @code{set args} before the next @code{run} is the only way to run | |
2074 | it again without arguments. | |
2075 | ||
2076 | @kindex show args | |
2077 | @item show args | |
2078 | Show the arguments to give your program when it is started. | |
2079 | @end table | |
2080 | ||
6d2ebf8b | 2081 | @node Environment |
79a6e687 | 2082 | @section Your Program's Environment |
c906108c SS |
2083 | |
2084 | @cindex environment (of your program) | |
2085 | The @dfn{environment} consists of a set of environment variables and | |
2086 | their values. Environment variables conventionally record such things as | |
2087 | your user name, your home directory, your terminal type, and your search | |
2088 | path for programs to run. Usually you set up environment variables with | |
2089 | the shell and they are inherited by all the other programs you run. When | |
2090 | debugging, it can be useful to try running your program with a modified | |
2091 | environment without having to start @value{GDBN} over again. | |
2092 | ||
2093 | @table @code | |
2094 | @kindex path | |
2095 | @item path @var{directory} | |
2096 | Add @var{directory} to the front of the @code{PATH} environment variable | |
17cc6a06 EZ |
2097 | (the search path for executables) that will be passed to your program. |
2098 | The value of @code{PATH} used by @value{GDBN} does not change. | |
d4f3574e SS |
2099 | You may specify several directory names, separated by whitespace or by a |
2100 | system-dependent separator character (@samp{:} on Unix, @samp{;} on | |
2101 | MS-DOS and MS-Windows). If @var{directory} is already in the path, it | |
2102 | is moved to the front, so it is searched sooner. | |
c906108c SS |
2103 | |
2104 | You can use the string @samp{$cwd} to refer to whatever is the current | |
2105 | working directory at the time @value{GDBN} searches the path. If you | |
2106 | use @samp{.} instead, it refers to the directory where you executed the | |
2107 | @code{path} command. @value{GDBN} replaces @samp{.} in the | |
2108 | @var{directory} argument (with the current path) before adding | |
2109 | @var{directory} to the search path. | |
2110 | @c 'path' is explicitly nonrepeatable, but RMS points out it is silly to | |
2111 | @c document that, since repeating it would be a no-op. | |
2112 | ||
2113 | @kindex show paths | |
2114 | @item show paths | |
2115 | Display the list of search paths for executables (the @code{PATH} | |
2116 | environment variable). | |
2117 | ||
2118 | @kindex show environment | |
2119 | @item show environment @r{[}@var{varname}@r{]} | |
2120 | Print the value of environment variable @var{varname} to be given to | |
2121 | your program when it starts. If you do not supply @var{varname}, | |
2122 | print the names and values of all environment variables to be given to | |
2123 | your program. You can abbreviate @code{environment} as @code{env}. | |
2124 | ||
2125 | @kindex set environment | |
53a5351d | 2126 | @item set environment @var{varname} @r{[}=@var{value}@r{]} |
c906108c SS |
2127 | Set environment variable @var{varname} to @var{value}. The value |
2128 | changes for your program only, not for @value{GDBN} itself. @var{value} may | |
2129 | be any string; the values of environment variables are just strings, and | |
2130 | any interpretation is supplied by your program itself. The @var{value} | |
2131 | parameter is optional; if it is eliminated, the variable is set to a | |
2132 | null value. | |
2133 | @c "any string" here does not include leading, trailing | |
2134 | @c blanks. Gnu asks: does anyone care? | |
2135 | ||
2136 | For example, this command: | |
2137 | ||
474c8240 | 2138 | @smallexample |
c906108c | 2139 | set env USER = foo |
474c8240 | 2140 | @end smallexample |
c906108c SS |
2141 | |
2142 | @noindent | |
d4f3574e | 2143 | tells the debugged program, when subsequently run, that its user is named |
c906108c SS |
2144 | @samp{foo}. (The spaces around @samp{=} are used for clarity here; they |
2145 | are not actually required.) | |
2146 | ||
2147 | @kindex unset environment | |
2148 | @item unset environment @var{varname} | |
2149 | Remove variable @var{varname} from the environment to be passed to your | |
2150 | program. This is different from @samp{set env @var{varname} =}; | |
2151 | @code{unset environment} removes the variable from the environment, | |
2152 | rather than assigning it an empty value. | |
2153 | @end table | |
2154 | ||
d4f3574e SS |
2155 | @emph{Warning:} On Unix systems, @value{GDBN} runs your program using |
2156 | the shell indicated | |
c906108c SS |
2157 | by your @code{SHELL} environment variable if it exists (or |
2158 | @code{/bin/sh} if not). If your @code{SHELL} variable names a shell | |
2159 | that runs an initialization file---such as @file{.cshrc} for C-shell, or | |
2160 | @file{.bashrc} for BASH---any variables you set in that file affect | |
2161 | your program. You may wish to move setting of environment variables to | |
2162 | files that are only run when you sign on, such as @file{.login} or | |
2163 | @file{.profile}. | |
2164 | ||
6d2ebf8b | 2165 | @node Working Directory |
79a6e687 | 2166 | @section Your Program's Working Directory |
c906108c SS |
2167 | |
2168 | @cindex working directory (of your program) | |
2169 | Each time you start your program with @code{run}, it inherits its | |
2170 | working directory from the current working directory of @value{GDBN}. | |
2171 | The @value{GDBN} working directory is initially whatever it inherited | |
2172 | from its parent process (typically the shell), but you can specify a new | |
2173 | working directory in @value{GDBN} with the @code{cd} command. | |
2174 | ||
2175 | The @value{GDBN} working directory also serves as a default for the commands | |
2176 | that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to | |
79a6e687 | 2177 | Specify Files}. |
c906108c SS |
2178 | |
2179 | @table @code | |
2180 | @kindex cd | |
721c2651 | 2181 | @cindex change working directory |
c906108c SS |
2182 | @item cd @var{directory} |
2183 | Set the @value{GDBN} working directory to @var{directory}. | |
2184 | ||
2185 | @kindex pwd | |
2186 | @item pwd | |
2187 | Print the @value{GDBN} working directory. | |
2188 | @end table | |
2189 | ||
60bf7e09 EZ |
2190 | It is generally impossible to find the current working directory of |
2191 | the process being debugged (since a program can change its directory | |
2192 | during its run). If you work on a system where @value{GDBN} is | |
2193 | configured with the @file{/proc} support, you can use the @code{info | |
2194 | proc} command (@pxref{SVR4 Process Information}) to find out the | |
2195 | current working directory of the debuggee. | |
2196 | ||
6d2ebf8b | 2197 | @node Input/Output |
79a6e687 | 2198 | @section Your Program's Input and Output |
c906108c SS |
2199 | |
2200 | @cindex redirection | |
2201 | @cindex i/o | |
2202 | @cindex terminal | |
2203 | By default, the program you run under @value{GDBN} does input and output to | |
5d161b24 | 2204 | the same terminal that @value{GDBN} uses. @value{GDBN} switches the terminal |
c906108c SS |
2205 | to its own terminal modes to interact with you, but it records the terminal |
2206 | modes your program was using and switches back to them when you continue | |
2207 | running your program. | |
2208 | ||
2209 | @table @code | |
2210 | @kindex info terminal | |
2211 | @item info terminal | |
2212 | Displays information recorded by @value{GDBN} about the terminal modes your | |
2213 | program is using. | |
2214 | @end table | |
2215 | ||
2216 | You can redirect your program's input and/or output using shell | |
2217 | redirection with the @code{run} command. For example, | |
2218 | ||
474c8240 | 2219 | @smallexample |
c906108c | 2220 | run > outfile |
474c8240 | 2221 | @end smallexample |
c906108c SS |
2222 | |
2223 | @noindent | |
2224 | starts your program, diverting its output to the file @file{outfile}. | |
2225 | ||
2226 | @kindex tty | |
2227 | @cindex controlling terminal | |
2228 | Another way to specify where your program should do input and output is | |
2229 | with the @code{tty} command. This command accepts a file name as | |
2230 | argument, and causes this file to be the default for future @code{run} | |
2231 | commands. It also resets the controlling terminal for the child | |
2232 | process, for future @code{run} commands. For example, | |
2233 | ||
474c8240 | 2234 | @smallexample |
c906108c | 2235 | tty /dev/ttyb |
474c8240 | 2236 | @end smallexample |
c906108c SS |
2237 | |
2238 | @noindent | |
2239 | directs that processes started with subsequent @code{run} commands | |
2240 | default to do input and output on the terminal @file{/dev/ttyb} and have | |
2241 | that as their controlling terminal. | |
2242 | ||
2243 | An explicit redirection in @code{run} overrides the @code{tty} command's | |
2244 | effect on the input/output device, but not its effect on the controlling | |
2245 | terminal. | |
2246 | ||
2247 | When you use the @code{tty} command or redirect input in the @code{run} | |
2248 | command, only the input @emph{for your program} is affected. The input | |
3cb3b8df BR |
2249 | for @value{GDBN} still comes from your terminal. @code{tty} is an alias |
2250 | for @code{set inferior-tty}. | |
2251 | ||
2252 | @cindex inferior tty | |
2253 | @cindex set inferior controlling terminal | |
2254 | You can use the @code{show inferior-tty} command to tell @value{GDBN} to | |
2255 | display the name of the terminal that will be used for future runs of your | |
2256 | program. | |
2257 | ||
2258 | @table @code | |
2259 | @item set inferior-tty /dev/ttyb | |
2260 | @kindex set inferior-tty | |
2261 | Set the tty for the program being debugged to /dev/ttyb. | |
2262 | ||
2263 | @item show inferior-tty | |
2264 | @kindex show inferior-tty | |
2265 | Show the current tty for the program being debugged. | |
2266 | @end table | |
c906108c | 2267 | |
6d2ebf8b | 2268 | @node Attach |
79a6e687 | 2269 | @section Debugging an Already-running Process |
c906108c SS |
2270 | @kindex attach |
2271 | @cindex attach | |
2272 | ||
2273 | @table @code | |
2274 | @item attach @var{process-id} | |
2275 | This command attaches to a running process---one that was started | |
2276 | outside @value{GDBN}. (@code{info files} shows your active | |
2277 | targets.) The command takes as argument a process ID. The usual way to | |
09d4efe1 | 2278 | find out the @var{process-id} of a Unix process is with the @code{ps} utility, |
c906108c SS |
2279 | or with the @samp{jobs -l} shell command. |
2280 | ||
2281 | @code{attach} does not repeat if you press @key{RET} a second time after | |
2282 | executing the command. | |
2283 | @end table | |
2284 | ||
2285 | To use @code{attach}, your program must be running in an environment | |
2286 | which supports processes; for example, @code{attach} does not work for | |
2287 | programs on bare-board targets that lack an operating system. You must | |
2288 | also have permission to send the process a signal. | |
2289 | ||
2290 | When you use @code{attach}, the debugger finds the program running in | |
2291 | the process first by looking in the current working directory, then (if | |
2292 | the program is not found) by using the source file search path | |
79a6e687 | 2293 | (@pxref{Source Path, ,Specifying Source Directories}). You can also use |
c906108c SS |
2294 | the @code{file} command to load the program. @xref{Files, ,Commands to |
2295 | Specify Files}. | |
2296 | ||
2297 | The first thing @value{GDBN} does after arranging to debug the specified | |
2298 | process is to stop it. You can examine and modify an attached process | |
53a5351d JM |
2299 | with all the @value{GDBN} commands that are ordinarily available when |
2300 | you start processes with @code{run}. You can insert breakpoints; you | |
2301 | can step and continue; you can modify storage. If you would rather the | |
2302 | process continue running, you may use the @code{continue} command after | |
c906108c SS |
2303 | attaching @value{GDBN} to the process. |
2304 | ||
2305 | @table @code | |
2306 | @kindex detach | |
2307 | @item detach | |
2308 | When you have finished debugging the attached process, you can use the | |
2309 | @code{detach} command to release it from @value{GDBN} control. Detaching | |
2310 | the process continues its execution. After the @code{detach} command, | |
2311 | that process and @value{GDBN} become completely independent once more, and you | |
2312 | are ready to @code{attach} another process or start one with @code{run}. | |
2313 | @code{detach} does not repeat if you press @key{RET} again after | |
2314 | executing the command. | |
2315 | @end table | |
2316 | ||
159fcc13 JK |
2317 | If you exit @value{GDBN} while you have an attached process, you detach |
2318 | that process. If you use the @code{run} command, you kill that process. | |
2319 | By default, @value{GDBN} asks for confirmation if you try to do either of these | |
2320 | things; you can control whether or not you need to confirm by using the | |
2321 | @code{set confirm} command (@pxref{Messages/Warnings, ,Optional Warnings and | |
79a6e687 | 2322 | Messages}). |
c906108c | 2323 | |
6d2ebf8b | 2324 | @node Kill Process |
79a6e687 | 2325 | @section Killing the Child Process |
c906108c SS |
2326 | |
2327 | @table @code | |
2328 | @kindex kill | |
2329 | @item kill | |
2330 | Kill the child process in which your program is running under @value{GDBN}. | |
2331 | @end table | |
2332 | ||
2333 | This command is useful if you wish to debug a core dump instead of a | |
2334 | running process. @value{GDBN} ignores any core dump file while your program | |
2335 | is running. | |
2336 | ||
2337 | On some operating systems, a program cannot be executed outside @value{GDBN} | |
2338 | while you have breakpoints set on it inside @value{GDBN}. You can use the | |
2339 | @code{kill} command in this situation to permit running your program | |
2340 | outside the debugger. | |
2341 | ||
2342 | The @code{kill} command is also useful if you wish to recompile and | |
2343 | relink your program, since on many systems it is impossible to modify an | |
2344 | executable file while it is running in a process. In this case, when you | |
2345 | next type @code{run}, @value{GDBN} notices that the file has changed, and | |
2346 | reads the symbol table again (while trying to preserve your current | |
2347 | breakpoint settings). | |
2348 | ||
b77209e0 PA |
2349 | @node Inferiors |
2350 | @section Debugging Multiple Inferiors | |
2351 | ||
2352 | Some @value{GDBN} targets are able to run multiple processes created | |
2353 | from a single executable. This can happen, for instance, with an | |
2354 | embedded system reporting back several processes via the remote | |
2355 | protocol. | |
2356 | ||
2357 | @cindex inferior | |
2358 | @value{GDBN} represents the state of each program execution with an | |
2359 | object called an @dfn{inferior}. An inferior typically corresponds to | |
2360 | a process, but is more general and applies also to targets that do not | |
2361 | have processes. Inferiors may be created before a process runs, and | |
2362 | may (in future) be retained after a process exits. Each run of an | |
2363 | executable creates a new inferior, as does each attachment to an | |
2364 | existing process. Inferiors have unique identifiers that are | |
2365 | different from process ids, and may optionally be named as well. | |
2366 | Usually each inferior will also have its own distinct address space, | |
2367 | although some embedded targets may have several inferiors running in | |
2368 | different parts of a single space. | |
2369 | ||
2370 | Each inferior may in turn have multiple threads running in it. | |
2371 | ||
2372 | To find out what inferiors exist at any moment, use @code{info inferiors}: | |
2373 | ||
2374 | @table @code | |
2375 | @kindex info inferiors | |
2376 | @item info inferiors | |
2377 | Print a list of all inferiors currently being managed by @value{GDBN}. | |
3a1ff0b6 PA |
2378 | |
2379 | @value{GDBN} displays for each inferior (in this order): | |
2380 | ||
2381 | @enumerate | |
2382 | @item | |
2383 | the inferior number assigned by @value{GDBN} | |
2384 | ||
2385 | @item | |
2386 | the target system's inferior identifier | |
2387 | @end enumerate | |
2388 | ||
2389 | @noindent | |
2390 | An asterisk @samp{*} preceding the @value{GDBN} inferior number | |
2391 | indicates the current inferior. | |
2392 | ||
2393 | For example, | |
2277426b | 2394 | @end table |
3a1ff0b6 PA |
2395 | @c end table here to get a little more width for example |
2396 | ||
2397 | @smallexample | |
2398 | (@value{GDBP}) info inferiors | |
2399 | Num Description | |
2400 | * 1 process 2307 | |
2401 | 2 process 3401 | |
2402 | @end smallexample | |
2277426b PA |
2403 | |
2404 | To switch focus between inferiors, use the @code{inferior} command: | |
2405 | ||
2406 | @table @code | |
3a1ff0b6 PA |
2407 | @kindex inferior @var{infno} |
2408 | @item inferior @var{infno} | |
2409 | Make inferior number @var{infno} the current inferior. The argument | |
2410 | @var{infno} is the inferior number assigned by @value{GDBN}, as shown | |
2411 | in the first field of the @samp{info inferiors} display. | |
2277426b PA |
2412 | @end table |
2413 | ||
2414 | To quit debugging one of the inferiors, you can either detach from it | |
2415 | by using the @w{@code{detach inferior}} command (allowing it to run | |
2416 | independently), or kill it using the @w{@code{kill inferior}} command: | |
2417 | ||
2418 | @table @code | |
3a1ff0b6 PA |
2419 | @kindex detach inferior @var{infno} |
2420 | @item detach inferior @var{infno} | |
2277426b | 2421 | Detach from the inferior identified by @value{GDBN} inferior number |
3a1ff0b6 | 2422 | @var{infno}, and remove it from the inferior list. |
2277426b | 2423 | |
3a1ff0b6 PA |
2424 | @kindex kill inferior @var{infno} |
2425 | @item kill inferior @var{infno} | |
2277426b | 2426 | Kill the inferior identified by @value{GDBN} inferior number |
3a1ff0b6 | 2427 | @var{infno}, and remove it from the inferior list. |
2277426b PA |
2428 | @end table |
2429 | ||
2430 | To be notified when inferiors are started or exit under @value{GDBN}'s | |
2431 | control use @w{@code{set print inferior-events}}: | |
b77209e0 | 2432 | |
2277426b | 2433 | @table @code |
b77209e0 PA |
2434 | @kindex set print inferior-events |
2435 | @cindex print messages on inferior start and exit | |
2436 | @item set print inferior-events | |
2437 | @itemx set print inferior-events on | |
2438 | @itemx set print inferior-events off | |
2439 | The @code{set print inferior-events} command allows you to enable or | |
2440 | disable printing of messages when @value{GDBN} notices that new | |
2441 | inferiors have started or that inferiors have exited or have been | |
2442 | detached. By default, these messages will not be printed. | |
2443 | ||
2444 | @kindex show print inferior-events | |
2445 | @item show print inferior-events | |
2446 | Show whether messages will be printed when @value{GDBN} detects that | |
2447 | inferiors have started, exited or have been detached. | |
2448 | @end table | |
2449 | ||
6d2ebf8b | 2450 | @node Threads |
79a6e687 | 2451 | @section Debugging Programs with Multiple Threads |
c906108c SS |
2452 | |
2453 | @cindex threads of execution | |
2454 | @cindex multiple threads | |
2455 | @cindex switching threads | |
2456 | In some operating systems, such as HP-UX and Solaris, a single program | |
2457 | may have more than one @dfn{thread} of execution. The precise semantics | |
2458 | of threads differ from one operating system to another, but in general | |
2459 | the threads of a single program are akin to multiple processes---except | |
2460 | that they share one address space (that is, they can all examine and | |
2461 | modify the same variables). On the other hand, each thread has its own | |
2462 | registers and execution stack, and perhaps private memory. | |
2463 | ||
2464 | @value{GDBN} provides these facilities for debugging multi-thread | |
2465 | programs: | |
2466 | ||
2467 | @itemize @bullet | |
2468 | @item automatic notification of new threads | |
2469 | @item @samp{thread @var{threadno}}, a command to switch among threads | |
2470 | @item @samp{info threads}, a command to inquire about existing threads | |
5d161b24 | 2471 | @item @samp{thread apply [@var{threadno}] [@var{all}] @var{args}}, |
c906108c SS |
2472 | a command to apply a command to a list of threads |
2473 | @item thread-specific breakpoints | |
93815fbf VP |
2474 | @item @samp{set print thread-events}, which controls printing of |
2475 | messages on thread start and exit. | |
17a37d48 PP |
2476 | @item @samp{set libthread-db-search-path @var{path}}, which lets |
2477 | the user specify which @code{libthread_db} to use if the default choice | |
2478 | isn't compatible with the program. | |
c906108c SS |
2479 | @end itemize |
2480 | ||
c906108c SS |
2481 | @quotation |
2482 | @emph{Warning:} These facilities are not yet available on every | |
2483 | @value{GDBN} configuration where the operating system supports threads. | |
2484 | If your @value{GDBN} does not support threads, these commands have no | |
2485 | effect. For example, a system without thread support shows no output | |
2486 | from @samp{info threads}, and always rejects the @code{thread} command, | |
2487 | like this: | |
2488 | ||
2489 | @smallexample | |
2490 | (@value{GDBP}) info threads | |
2491 | (@value{GDBP}) thread 1 | |
2492 | Thread ID 1 not known. Use the "info threads" command to | |
2493 | see the IDs of currently known threads. | |
2494 | @end smallexample | |
2495 | @c FIXME to implementors: how hard would it be to say "sorry, this GDB | |
2496 | @c doesn't support threads"? | |
2497 | @end quotation | |
c906108c SS |
2498 | |
2499 | @cindex focus of debugging | |
2500 | @cindex current thread | |
2501 | The @value{GDBN} thread debugging facility allows you to observe all | |
2502 | threads while your program runs---but whenever @value{GDBN} takes | |
2503 | control, one thread in particular is always the focus of debugging. | |
2504 | This thread is called the @dfn{current thread}. Debugging commands show | |
2505 | program information from the perspective of the current thread. | |
2506 | ||
41afff9a | 2507 | @cindex @code{New} @var{systag} message |
c906108c SS |
2508 | @cindex thread identifier (system) |
2509 | @c FIXME-implementors!! It would be more helpful if the [New...] message | |
2510 | @c included GDB's numeric thread handle, so you could just go to that | |
2511 | @c thread without first checking `info threads'. | |
2512 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2513 | the target system's identification for the thread with a message in the | |
2514 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2515 | whose form varies depending on the particular system. For example, on | |
8807d78b | 2516 | @sc{gnu}/Linux, you might see |
c906108c | 2517 | |
474c8240 | 2518 | @smallexample |
8807d78b | 2519 | [New Thread 46912507313328 (LWP 25582)] |
474c8240 | 2520 | @end smallexample |
c906108c SS |
2521 | |
2522 | @noindent | |
2523 | when @value{GDBN} notices a new thread. In contrast, on an SGI system, | |
2524 | the @var{systag} is simply something like @samp{process 368}, with no | |
2525 | further qualifier. | |
2526 | ||
2527 | @c FIXME!! (1) Does the [New...] message appear even for the very first | |
2528 | @c thread of a program, or does it only appear for the | |
6ca652b0 | 2529 | @c second---i.e.@: when it becomes obvious we have a multithread |
c906108c SS |
2530 | @c program? |
2531 | @c (2) *Is* there necessarily a first thread always? Or do some | |
2532 | @c multithread systems permit starting a program with multiple | |
5d161b24 | 2533 | @c threads ab initio? |
c906108c SS |
2534 | |
2535 | @cindex thread number | |
2536 | @cindex thread identifier (GDB) | |
2537 | For debugging purposes, @value{GDBN} associates its own thread | |
2538 | number---always a single integer---with each thread in your program. | |
2539 | ||
2540 | @table @code | |
2541 | @kindex info threads | |
2542 | @item info threads | |
2543 | Display a summary of all threads currently in your | |
2544 | program. @value{GDBN} displays for each thread (in this order): | |
2545 | ||
2546 | @enumerate | |
09d4efe1 EZ |
2547 | @item |
2548 | the thread number assigned by @value{GDBN} | |
c906108c | 2549 | |
09d4efe1 EZ |
2550 | @item |
2551 | the target system's thread identifier (@var{systag}) | |
c906108c | 2552 | |
09d4efe1 EZ |
2553 | @item |
2554 | the current stack frame summary for that thread | |
c906108c SS |
2555 | @end enumerate |
2556 | ||
2557 | @noindent | |
2558 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2559 | indicates the current thread. | |
2560 | ||
5d161b24 | 2561 | For example, |
c906108c SS |
2562 | @end table |
2563 | @c end table here to get a little more width for example | |
2564 | ||
2565 | @smallexample | |
2566 | (@value{GDBP}) info threads | |
2567 | 3 process 35 thread 27 0x34e5 in sigpause () | |
2568 | 2 process 35 thread 23 0x34e5 in sigpause () | |
2569 | * 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8) | |
2570 | at threadtest.c:68 | |
2571 | @end smallexample | |
53a5351d JM |
2572 | |
2573 | On HP-UX systems: | |
c906108c | 2574 | |
4644b6e3 EZ |
2575 | @cindex debugging multithreaded programs (on HP-UX) |
2576 | @cindex thread identifier (GDB), on HP-UX | |
c906108c SS |
2577 | For debugging purposes, @value{GDBN} associates its own thread |
2578 | number---a small integer assigned in thread-creation order---with each | |
2579 | thread in your program. | |
2580 | ||
41afff9a EZ |
2581 | @cindex @code{New} @var{systag} message, on HP-UX |
2582 | @cindex thread identifier (system), on HP-UX | |
c906108c SS |
2583 | @c FIXME-implementors!! It would be more helpful if the [New...] message |
2584 | @c included GDB's numeric thread handle, so you could just go to that | |
2585 | @c thread without first checking `info threads'. | |
2586 | Whenever @value{GDBN} detects a new thread in your program, it displays | |
2587 | both @value{GDBN}'s thread number and the target system's identification for the thread with a message in the | |
2588 | form @samp{[New @var{systag}]}. @var{systag} is a thread identifier | |
2589 | whose form varies depending on the particular system. For example, on | |
2590 | HP-UX, you see | |
2591 | ||
474c8240 | 2592 | @smallexample |
c906108c | 2593 | [New thread 2 (system thread 26594)] |
474c8240 | 2594 | @end smallexample |
c906108c SS |
2595 | |
2596 | @noindent | |
5d161b24 | 2597 | when @value{GDBN} notices a new thread. |
c906108c SS |
2598 | |
2599 | @table @code | |
4644b6e3 | 2600 | @kindex info threads (HP-UX) |
c906108c SS |
2601 | @item info threads |
2602 | Display a summary of all threads currently in your | |
2603 | program. @value{GDBN} displays for each thread (in this order): | |
2604 | ||
2605 | @enumerate | |
2606 | @item the thread number assigned by @value{GDBN} | |
2607 | ||
2608 | @item the target system's thread identifier (@var{systag}) | |
2609 | ||
2610 | @item the current stack frame summary for that thread | |
2611 | @end enumerate | |
2612 | ||
2613 | @noindent | |
2614 | An asterisk @samp{*} to the left of the @value{GDBN} thread number | |
2615 | indicates the current thread. | |
2616 | ||
5d161b24 | 2617 | For example, |
c906108c SS |
2618 | @end table |
2619 | @c end table here to get a little more width for example | |
2620 | ||
474c8240 | 2621 | @smallexample |
c906108c | 2622 | (@value{GDBP}) info threads |
6d2ebf8b SS |
2623 | * 3 system thread 26607 worker (wptr=0x7b09c318 "@@") \@* |
2624 | at quicksort.c:137 | |
2625 | 2 system thread 26606 0x7b0030d8 in __ksleep () \@* | |
2626 | from /usr/lib/libc.2 | |
2627 | 1 system thread 27905 0x7b003498 in _brk () \@* | |
2628 | from /usr/lib/libc.2 | |
474c8240 | 2629 | @end smallexample |
c906108c | 2630 | |
c45da7e6 EZ |
2631 | On Solaris, you can display more information about user threads with a |
2632 | Solaris-specific command: | |
2633 | ||
2634 | @table @code | |
2635 | @item maint info sol-threads | |
2636 | @kindex maint info sol-threads | |
2637 | @cindex thread info (Solaris) | |
2638 | Display info on Solaris user threads. | |
2639 | @end table | |
2640 | ||
c906108c SS |
2641 | @table @code |
2642 | @kindex thread @var{threadno} | |
2643 | @item thread @var{threadno} | |
2644 | Make thread number @var{threadno} the current thread. The command | |
2645 | argument @var{threadno} is the internal @value{GDBN} thread number, as | |
2646 | shown in the first field of the @samp{info threads} display. | |
2647 | @value{GDBN} responds by displaying the system identifier of the thread | |
2648 | you selected, and its current stack frame summary: | |
2649 | ||
2650 | @smallexample | |
2651 | @c FIXME!! This example made up; find a @value{GDBN} w/threads and get real one | |
2652 | (@value{GDBP}) thread 2 | |
c906108c | 2653 | [Switching to process 35 thread 23] |
c906108c SS |
2654 | 0x34e5 in sigpause () |
2655 | @end smallexample | |
2656 | ||
2657 | @noindent | |
2658 | As with the @samp{[New @dots{}]} message, the form of the text after | |
2659 | @samp{Switching to} depends on your system's conventions for identifying | |
5d161b24 | 2660 | threads. |
c906108c | 2661 | |
9c16f35a | 2662 | @kindex thread apply |
638ac427 | 2663 | @cindex apply command to several threads |
839c27b7 EZ |
2664 | @item thread apply [@var{threadno}] [@var{all}] @var{command} |
2665 | The @code{thread apply} command allows you to apply the named | |
2666 | @var{command} to one or more threads. Specify the numbers of the | |
2667 | threads that you want affected with the command argument | |
2668 | @var{threadno}. It can be a single thread number, one of the numbers | |
2669 | shown in the first field of the @samp{info threads} display; or it | |
2670 | could be a range of thread numbers, as in @code{2-4}. To apply a | |
2671 | command to all threads, type @kbd{thread apply all @var{command}}. | |
93815fbf VP |
2672 | |
2673 | @kindex set print thread-events | |
2674 | @cindex print messages on thread start and exit | |
2675 | @item set print thread-events | |
2676 | @itemx set print thread-events on | |
2677 | @itemx set print thread-events off | |
2678 | The @code{set print thread-events} command allows you to enable or | |
2679 | disable printing of messages when @value{GDBN} notices that new threads have | |
2680 | started or that threads have exited. By default, these messages will | |
2681 | be printed if detection of these events is supported by the target. | |
2682 | Note that these messages cannot be disabled on all targets. | |
2683 | ||
2684 | @kindex show print thread-events | |
2685 | @item show print thread-events | |
2686 | Show whether messages will be printed when @value{GDBN} detects that threads | |
2687 | have started and exited. | |
c906108c SS |
2688 | @end table |
2689 | ||
79a6e687 | 2690 | @xref{Thread Stops,,Stopping and Starting Multi-thread Programs}, for |
c906108c SS |
2691 | more information about how @value{GDBN} behaves when you stop and start |
2692 | programs with multiple threads. | |
2693 | ||
79a6e687 | 2694 | @xref{Set Watchpoints,,Setting Watchpoints}, for information about |
c906108c | 2695 | watchpoints in programs with multiple threads. |
c906108c | 2696 | |
17a37d48 PP |
2697 | @table @code |
2698 | @kindex set libthread-db-search-path | |
2699 | @cindex search path for @code{libthread_db} | |
2700 | @item set libthread-db-search-path @r{[}@var{path}@r{]} | |
2701 | If this variable is set, @var{path} is a colon-separated list of | |
2702 | directories @value{GDBN} will use to search for @code{libthread_db}. | |
2703 | If you omit @var{path}, @samp{libthread-db-search-path} will be reset to | |
2704 | an empty list. | |
2705 | ||
2706 | On @sc{gnu}/Linux and Solaris systems, @value{GDBN} uses a ``helper'' | |
2707 | @code{libthread_db} library to obtain information about threads in the | |
2708 | inferior process. @value{GDBN} will use @samp{libthread-db-search-path} | |
2709 | to find @code{libthread_db}. If that fails, @value{GDBN} will continue | |
2710 | with default system shared library directories, and finally the directory | |
2711 | from which @code{libpthread} was loaded in the inferior process. | |
2712 | ||
2713 | For any @code{libthread_db} library @value{GDBN} finds in above directories, | |
2714 | @value{GDBN} attempts to initialize it with the current inferior process. | |
2715 | If this initialization fails (which could happen because of a version | |
2716 | mismatch between @code{libthread_db} and @code{libpthread}), @value{GDBN} | |
2717 | will unload @code{libthread_db}, and continue with the next directory. | |
2718 | If none of @code{libthread_db} libraries initialize successfully, | |
2719 | @value{GDBN} will issue a warning and thread debugging will be disabled. | |
2720 | ||
2721 | Setting @code{libthread-db-search-path} is currently implemented | |
2722 | only on some platforms. | |
2723 | ||
2724 | @kindex show libthread-db-search-path | |
2725 | @item show libthread-db-search-path | |
2726 | Display current libthread_db search path. | |
2727 | @end table | |
2728 | ||
6d2ebf8b | 2729 | @node Processes |
79a6e687 | 2730 | @section Debugging Programs with Multiple Processes |
c906108c SS |
2731 | |
2732 | @cindex fork, debugging programs which call | |
2733 | @cindex multiple processes | |
2734 | @cindex processes, multiple | |
53a5351d JM |
2735 | On most systems, @value{GDBN} has no special support for debugging |
2736 | programs which create additional processes using the @code{fork} | |
2737 | function. When a program forks, @value{GDBN} will continue to debug the | |
2738 | parent process and the child process will run unimpeded. If you have | |
2739 | set a breakpoint in any code which the child then executes, the child | |
2740 | will get a @code{SIGTRAP} signal which (unless it catches the signal) | |
2741 | will cause it to terminate. | |
c906108c SS |
2742 | |
2743 | However, if you want to debug the child process there is a workaround | |
2744 | which isn't too painful. Put a call to @code{sleep} in the code which | |
2745 | the child process executes after the fork. It may be useful to sleep | |
2746 | only if a certain environment variable is set, or a certain file exists, | |
2747 | so that the delay need not occur when you don't want to run @value{GDBN} | |
2748 | on the child. While the child is sleeping, use the @code{ps} program to | |
2749 | get its process ID. Then tell @value{GDBN} (a new invocation of | |
2750 | @value{GDBN} if you are also debugging the parent process) to attach to | |
d4f3574e | 2751 | the child process (@pxref{Attach}). From that point on you can debug |
c906108c | 2752 | the child process just like any other process which you attached to. |
c906108c | 2753 | |
b51970ac DJ |
2754 | On some systems, @value{GDBN} provides support for debugging programs that |
2755 | create additional processes using the @code{fork} or @code{vfork} functions. | |
2756 | Currently, the only platforms with this feature are HP-UX (11.x and later | |
a6b151f1 | 2757 | only?) and @sc{gnu}/Linux (kernel version 2.5.60 and later). |
c906108c SS |
2758 | |
2759 | By default, when a program forks, @value{GDBN} will continue to debug | |
2760 | the parent process and the child process will run unimpeded. | |
2761 | ||
2762 | If you want to follow the child process instead of the parent process, | |
2763 | use the command @w{@code{set follow-fork-mode}}. | |
2764 | ||
2765 | @table @code | |
2766 | @kindex set follow-fork-mode | |
2767 | @item set follow-fork-mode @var{mode} | |
2768 | Set the debugger response to a program call of @code{fork} or | |
2769 | @code{vfork}. A call to @code{fork} or @code{vfork} creates a new | |
9c16f35a | 2770 | process. The @var{mode} argument can be: |
c906108c SS |
2771 | |
2772 | @table @code | |
2773 | @item parent | |
2774 | The original process is debugged after a fork. The child process runs | |
2df3850c | 2775 | unimpeded. This is the default. |
c906108c SS |
2776 | |
2777 | @item child | |
2778 | The new process is debugged after a fork. The parent process runs | |
2779 | unimpeded. | |
2780 | ||
c906108c SS |
2781 | @end table |
2782 | ||
9c16f35a | 2783 | @kindex show follow-fork-mode |
c906108c | 2784 | @item show follow-fork-mode |
2df3850c | 2785 | Display the current debugger response to a @code{fork} or @code{vfork} call. |
c906108c SS |
2786 | @end table |
2787 | ||
5c95884b MS |
2788 | @cindex debugging multiple processes |
2789 | On Linux, if you want to debug both the parent and child processes, use the | |
2790 | command @w{@code{set detach-on-fork}}. | |
2791 | ||
2792 | @table @code | |
2793 | @kindex set detach-on-fork | |
2794 | @item set detach-on-fork @var{mode} | |
2795 | Tells gdb whether to detach one of the processes after a fork, or | |
2796 | retain debugger control over them both. | |
2797 | ||
2798 | @table @code | |
2799 | @item on | |
2800 | The child process (or parent process, depending on the value of | |
2801 | @code{follow-fork-mode}) will be detached and allowed to run | |
2802 | independently. This is the default. | |
2803 | ||
2804 | @item off | |
2805 | Both processes will be held under the control of @value{GDBN}. | |
2806 | One process (child or parent, depending on the value of | |
2807 | @code{follow-fork-mode}) is debugged as usual, while the other | |
2808 | is held suspended. | |
2809 | ||
2810 | @end table | |
2811 | ||
11310833 NR |
2812 | @kindex show detach-on-fork |
2813 | @item show detach-on-fork | |
2814 | Show whether detach-on-fork mode is on/off. | |
5c95884b MS |
2815 | @end table |
2816 | ||
2277426b PA |
2817 | If you choose to set @samp{detach-on-fork} mode off, then @value{GDBN} |
2818 | will retain control of all forked processes (including nested forks). | |
2819 | You can list the forked processes under the control of @value{GDBN} by | |
2820 | using the @w{@code{info inferiors}} command, and switch from one fork | |
2821 | to another by using the @code{inferior} command (@pxref{Inferiors, | |
2822 | ,Debugging Multiple Inferiors}). | |
5c95884b MS |
2823 | |
2824 | To quit debugging one of the forked processes, you can either detach | |
2277426b PA |
2825 | from it by using the @w{@code{detach inferior}} command (allowing it |
2826 | to run independently), or kill it using the @w{@code{kill inferior}} | |
2827 | command. @xref{Inferiors, ,Debugging Multiple Inferiors}. | |
5c95884b | 2828 | |
c906108c SS |
2829 | If you ask to debug a child process and a @code{vfork} is followed by an |
2830 | @code{exec}, @value{GDBN} executes the new target up to the first | |
2831 | breakpoint in the new target. If you have a breakpoint set on | |
2832 | @code{main} in your original program, the breakpoint will also be set on | |
2833 | the child process's @code{main}. | |
2834 | ||
2277426b PA |
2835 | On some systems, when a child process is spawned by @code{vfork}, you |
2836 | cannot debug the child or parent until an @code{exec} call completes. | |
c906108c SS |
2837 | |
2838 | If you issue a @code{run} command to @value{GDBN} after an @code{exec} | |
2839 | call executes, the new target restarts. To restart the parent process, | |
2840 | use the @code{file} command with the parent executable name as its | |
2841 | argument. | |
2842 | ||
2843 | You can use the @code{catch} command to make @value{GDBN} stop whenever | |
2844 | a @code{fork}, @code{vfork}, or @code{exec} call is made. @xref{Set | |
79a6e687 | 2845 | Catchpoints, ,Setting Catchpoints}. |
c906108c | 2846 | |
5c95884b | 2847 | @node Checkpoint/Restart |
79a6e687 | 2848 | @section Setting a @emph{Bookmark} to Return to Later |
5c95884b MS |
2849 | |
2850 | @cindex checkpoint | |
2851 | @cindex restart | |
2852 | @cindex bookmark | |
2853 | @cindex snapshot of a process | |
2854 | @cindex rewind program state | |
2855 | ||
2856 | On certain operating systems@footnote{Currently, only | |
2857 | @sc{gnu}/Linux.}, @value{GDBN} is able to save a @dfn{snapshot} of a | |
2858 | program's state, called a @dfn{checkpoint}, and come back to it | |
2859 | later. | |
2860 | ||
2861 | Returning to a checkpoint effectively undoes everything that has | |
2862 | happened in the program since the @code{checkpoint} was saved. This | |
2863 | includes changes in memory, registers, and even (within some limits) | |
2864 | system state. Effectively, it is like going back in time to the | |
2865 | moment when the checkpoint was saved. | |
2866 | ||
2867 | Thus, if you're stepping thru a program and you think you're | |
2868 | getting close to the point where things go wrong, you can save | |
2869 | a checkpoint. Then, if you accidentally go too far and miss | |
2870 | the critical statement, instead of having to restart your program | |
2871 | from the beginning, you can just go back to the checkpoint and | |
2872 | start again from there. | |
2873 | ||
2874 | This can be especially useful if it takes a lot of time or | |
2875 | steps to reach the point where you think the bug occurs. | |
2876 | ||
2877 | To use the @code{checkpoint}/@code{restart} method of debugging: | |
2878 | ||
2879 | @table @code | |
2880 | @kindex checkpoint | |
2881 | @item checkpoint | |
2882 | Save a snapshot of the debugged program's current execution state. | |
2883 | The @code{checkpoint} command takes no arguments, but each checkpoint | |
2884 | is assigned a small integer id, similar to a breakpoint id. | |
2885 | ||
2886 | @kindex info checkpoints | |
2887 | @item info checkpoints | |
2888 | List the checkpoints that have been saved in the current debugging | |
2889 | session. For each checkpoint, the following information will be | |
2890 | listed: | |
2891 | ||
2892 | @table @code | |
2893 | @item Checkpoint ID | |
2894 | @item Process ID | |
2895 | @item Code Address | |
2896 | @item Source line, or label | |
2897 | @end table | |
2898 | ||
2899 | @kindex restart @var{checkpoint-id} | |
2900 | @item restart @var{checkpoint-id} | |
2901 | Restore the program state that was saved as checkpoint number | |
2902 | @var{checkpoint-id}. All program variables, registers, stack frames | |
2903 | etc.@: will be returned to the values that they had when the checkpoint | |
2904 | was saved. In essence, gdb will ``wind back the clock'' to the point | |
2905 | in time when the checkpoint was saved. | |
2906 | ||
2907 | Note that breakpoints, @value{GDBN} variables, command history etc. | |
2908 | are not affected by restoring a checkpoint. In general, a checkpoint | |
2909 | only restores things that reside in the program being debugged, not in | |
2910 | the debugger. | |
2911 | ||
b8db102d MS |
2912 | @kindex delete checkpoint @var{checkpoint-id} |
2913 | @item delete checkpoint @var{checkpoint-id} | |
5c95884b MS |
2914 | Delete the previously-saved checkpoint identified by @var{checkpoint-id}. |
2915 | ||
2916 | @end table | |
2917 | ||
2918 | Returning to a previously saved checkpoint will restore the user state | |
2919 | of the program being debugged, plus a significant subset of the system | |
2920 | (OS) state, including file pointers. It won't ``un-write'' data from | |
2921 | a file, but it will rewind the file pointer to the previous location, | |
2922 | so that the previously written data can be overwritten. For files | |
2923 | opened in read mode, the pointer will also be restored so that the | |
2924 | previously read data can be read again. | |
2925 | ||
2926 | Of course, characters that have been sent to a printer (or other | |
2927 | external device) cannot be ``snatched back'', and characters received | |
2928 | from eg.@: a serial device can be removed from internal program buffers, | |
2929 | but they cannot be ``pushed back'' into the serial pipeline, ready to | |
2930 | be received again. Similarly, the actual contents of files that have | |
2931 | been changed cannot be restored (at this time). | |
2932 | ||
2933 | However, within those constraints, you actually can ``rewind'' your | |
2934 | program to a previously saved point in time, and begin debugging it | |
2935 | again --- and you can change the course of events so as to debug a | |
2936 | different execution path this time. | |
2937 | ||
2938 | @cindex checkpoints and process id | |
2939 | Finally, there is one bit of internal program state that will be | |
2940 | different when you return to a checkpoint --- the program's process | |
2941 | id. Each checkpoint will have a unique process id (or @var{pid}), | |
2942 | and each will be different from the program's original @var{pid}. | |
2943 | If your program has saved a local copy of its process id, this could | |
2944 | potentially pose a problem. | |
2945 | ||
79a6e687 | 2946 | @subsection A Non-obvious Benefit of Using Checkpoints |
5c95884b MS |
2947 | |
2948 | On some systems such as @sc{gnu}/Linux, address space randomization | |
2949 | is performed on new processes for security reasons. This makes it | |
2950 | difficult or impossible to set a breakpoint, or watchpoint, on an | |
2951 | absolute address if you have to restart the program, since the | |
2952 | absolute location of a symbol will change from one execution to the | |
2953 | next. | |
2954 | ||
2955 | A checkpoint, however, is an @emph{identical} copy of a process. | |
2956 | Therefore if you create a checkpoint at (eg.@:) the start of main, | |
2957 | and simply return to that checkpoint instead of restarting the | |
2958 | process, you can avoid the effects of address randomization and | |
2959 | your symbols will all stay in the same place. | |
2960 | ||
6d2ebf8b | 2961 | @node Stopping |
c906108c SS |
2962 | @chapter Stopping and Continuing |
2963 | ||
2964 | The principal purposes of using a debugger are so that you can stop your | |
2965 | program before it terminates; or so that, if your program runs into | |
2966 | trouble, you can investigate and find out why. | |
2967 | ||
7a292a7a SS |
2968 | Inside @value{GDBN}, your program may stop for any of several reasons, |
2969 | such as a signal, a breakpoint, or reaching a new line after a | |
2970 | @value{GDBN} command such as @code{step}. You may then examine and | |
2971 | change variables, set new breakpoints or remove old ones, and then | |
2972 | continue execution. Usually, the messages shown by @value{GDBN} provide | |
2973 | ample explanation of the status of your program---but you can also | |
2974 | explicitly request this information at any time. | |
c906108c SS |
2975 | |
2976 | @table @code | |
2977 | @kindex info program | |
2978 | @item info program | |
2979 | Display information about the status of your program: whether it is | |
7a292a7a | 2980 | running or not, what process it is, and why it stopped. |
c906108c SS |
2981 | @end table |
2982 | ||
2983 | @menu | |
2984 | * Breakpoints:: Breakpoints, watchpoints, and catchpoints | |
2985 | * Continuing and Stepping:: Resuming execution | |
c906108c | 2986 | * Signals:: Signals |
c906108c | 2987 | * Thread Stops:: Stopping and starting multi-thread programs |
c906108c SS |
2988 | @end menu |
2989 | ||
6d2ebf8b | 2990 | @node Breakpoints |
79a6e687 | 2991 | @section Breakpoints, Watchpoints, and Catchpoints |
c906108c SS |
2992 | |
2993 | @cindex breakpoints | |
2994 | A @dfn{breakpoint} makes your program stop whenever a certain point in | |
2995 | the program is reached. For each breakpoint, you can add conditions to | |
2996 | control in finer detail whether your program stops. You can set | |
2997 | breakpoints with the @code{break} command and its variants (@pxref{Set | |
79a6e687 | 2998 | Breaks, ,Setting Breakpoints}), to specify the place where your program |
c906108c SS |
2999 | should stop by line number, function name or exact address in the |
3000 | program. | |
3001 | ||
09d4efe1 EZ |
3002 | On some systems, you can set breakpoints in shared libraries before |
3003 | the executable is run. There is a minor limitation on HP-UX systems: | |
3004 | you must wait until the executable is run in order to set breakpoints | |
3005 | in shared library routines that are not called directly by the program | |
3006 | (for example, routines that are arguments in a @code{pthread_create} | |
3007 | call). | |
c906108c SS |
3008 | |
3009 | @cindex watchpoints | |
fd60e0df | 3010 | @cindex data breakpoints |
c906108c SS |
3011 | @cindex memory tracing |
3012 | @cindex breakpoint on memory address | |
3013 | @cindex breakpoint on variable modification | |
3014 | A @dfn{watchpoint} is a special breakpoint that stops your program | |
fd60e0df | 3015 | when the value of an expression changes. The expression may be a value |
0ced0c34 | 3016 | of a variable, or it could involve values of one or more variables |
fd60e0df EZ |
3017 | combined by operators, such as @samp{a + b}. This is sometimes called |
3018 | @dfn{data breakpoints}. You must use a different command to set | |
79a6e687 | 3019 | watchpoints (@pxref{Set Watchpoints, ,Setting Watchpoints}), but aside |
fd60e0df EZ |
3020 | from that, you can manage a watchpoint like any other breakpoint: you |
3021 | enable, disable, and delete both breakpoints and watchpoints using the | |
3022 | same commands. | |
c906108c SS |
3023 | |
3024 | You can arrange to have values from your program displayed automatically | |
3025 | whenever @value{GDBN} stops at a breakpoint. @xref{Auto Display,, | |
79a6e687 | 3026 | Automatic Display}. |
c906108c SS |
3027 | |
3028 | @cindex catchpoints | |
3029 | @cindex breakpoint on events | |
3030 | A @dfn{catchpoint} is another special breakpoint that stops your program | |
b37052ae | 3031 | when a certain kind of event occurs, such as the throwing of a C@t{++} |
c906108c SS |
3032 | exception or the loading of a library. As with watchpoints, you use a |
3033 | different command to set a catchpoint (@pxref{Set Catchpoints, ,Setting | |
79a6e687 | 3034 | Catchpoints}), but aside from that, you can manage a catchpoint like any |
c906108c | 3035 | other breakpoint. (To stop when your program receives a signal, use the |
d4f3574e | 3036 | @code{handle} command; see @ref{Signals, ,Signals}.) |
c906108c SS |
3037 | |
3038 | @cindex breakpoint numbers | |
3039 | @cindex numbers for breakpoints | |
3040 | @value{GDBN} assigns a number to each breakpoint, watchpoint, or | |
3041 | catchpoint when you create it; these numbers are successive integers | |
3042 | starting with one. In many of the commands for controlling various | |
3043 | features of breakpoints you use the breakpoint number to say which | |
3044 | breakpoint you want to change. Each breakpoint may be @dfn{enabled} or | |
3045 | @dfn{disabled}; if disabled, it has no effect on your program until you | |
3046 | enable it again. | |
3047 | ||
c5394b80 JM |
3048 | @cindex breakpoint ranges |
3049 | @cindex ranges of breakpoints | |
3050 | Some @value{GDBN} commands accept a range of breakpoints on which to | |
3051 | operate. A breakpoint range is either a single breakpoint number, like | |
3052 | @samp{5}, or two such numbers, in increasing order, separated by a | |
3053 | hyphen, like @samp{5-7}. When a breakpoint range is given to a command, | |
d52fb0e9 | 3054 | all breakpoints in that range are operated on. |
c5394b80 | 3055 | |
c906108c SS |
3056 | @menu |
3057 | * Set Breaks:: Setting breakpoints | |
3058 | * Set Watchpoints:: Setting watchpoints | |
3059 | * Set Catchpoints:: Setting catchpoints | |
3060 | * Delete Breaks:: Deleting breakpoints | |
3061 | * Disabling:: Disabling breakpoints | |
3062 | * Conditions:: Break conditions | |
3063 | * Break Commands:: Breakpoint command lists | |
d4f3574e | 3064 | * Error in Breakpoints:: ``Cannot insert breakpoints'' |
79a6e687 | 3065 | * Breakpoint-related Warnings:: ``Breakpoint address adjusted...'' |
c906108c SS |
3066 | @end menu |
3067 | ||
6d2ebf8b | 3068 | @node Set Breaks |
79a6e687 | 3069 | @subsection Setting Breakpoints |
c906108c | 3070 | |
5d161b24 | 3071 | @c FIXME LMB what does GDB do if no code on line of breakpt? |
c906108c SS |
3072 | @c consider in particular declaration with/without initialization. |
3073 | @c | |
3074 | @c FIXME 2 is there stuff on this already? break at fun start, already init? | |
3075 | ||
3076 | @kindex break | |
41afff9a EZ |
3077 | @kindex b @r{(@code{break})} |
3078 | @vindex $bpnum@r{, convenience variable} | |
c906108c SS |
3079 | @cindex latest breakpoint |
3080 | Breakpoints are set with the @code{break} command (abbreviated | |
5d161b24 | 3081 | @code{b}). The debugger convenience variable @samp{$bpnum} records the |
f3b28801 | 3082 | number of the breakpoint you've set most recently; see @ref{Convenience |
79a6e687 | 3083 | Vars,, Convenience Variables}, for a discussion of what you can do with |
c906108c SS |
3084 | convenience variables. |
3085 | ||
c906108c | 3086 | @table @code |
2a25a5ba EZ |
3087 | @item break @var{location} |
3088 | Set a breakpoint at the given @var{location}, which can specify a | |
3089 | function name, a line number, or an address of an instruction. | |
3090 | (@xref{Specify Location}, for a list of all the possible ways to | |
3091 | specify a @var{location}.) The breakpoint will stop your program just | |
3092 | before it executes any of the code in the specified @var{location}. | |
3093 | ||
c906108c | 3094 | When using source languages that permit overloading of symbols, such as |
2a25a5ba | 3095 | C@t{++}, a function name may refer to more than one possible place to break. |
6ba66d6a JB |
3096 | @xref{Ambiguous Expressions,,Ambiguous Expressions}, for a discussion of |
3097 | that situation. | |
c906108c | 3098 | |
45ac276d | 3099 | It is also possible to insert a breakpoint that will stop the program |
2c88c651 JB |
3100 | only if a specific thread (@pxref{Thread-Specific Breakpoints}) |
3101 | or a specific task (@pxref{Ada Tasks}) hits that breakpoint. | |
45ac276d | 3102 | |
c906108c SS |
3103 | @item break |
3104 | When called without any arguments, @code{break} sets a breakpoint at | |
3105 | the next instruction to be executed in the selected stack frame | |
3106 | (@pxref{Stack, ,Examining the Stack}). In any selected frame but the | |
3107 | innermost, this makes your program stop as soon as control | |
3108 | returns to that frame. This is similar to the effect of a | |
3109 | @code{finish} command in the frame inside the selected frame---except | |
3110 | that @code{finish} does not leave an active breakpoint. If you use | |
3111 | @code{break} without an argument in the innermost frame, @value{GDBN} stops | |
3112 | the next time it reaches the current location; this may be useful | |
3113 | inside loops. | |
3114 | ||
3115 | @value{GDBN} normally ignores breakpoints when it resumes execution, until at | |
3116 | least one instruction has been executed. If it did not do this, you | |
3117 | would be unable to proceed past a breakpoint without first disabling the | |
3118 | breakpoint. This rule applies whether or not the breakpoint already | |
3119 | existed when your program stopped. | |
3120 | ||
3121 | @item break @dots{} if @var{cond} | |
3122 | Set a breakpoint with condition @var{cond}; evaluate the expression | |
3123 | @var{cond} each time the breakpoint is reached, and stop only if the | |
3124 | value is nonzero---that is, if @var{cond} evaluates as true. | |
3125 | @samp{@dots{}} stands for one of the possible arguments described | |
3126 | above (or no argument) specifying where to break. @xref{Conditions, | |
79a6e687 | 3127 | ,Break Conditions}, for more information on breakpoint conditions. |
c906108c SS |
3128 | |
3129 | @kindex tbreak | |
3130 | @item tbreak @var{args} | |
3131 | Set a breakpoint enabled only for one stop. @var{args} are the | |
3132 | same as for the @code{break} command, and the breakpoint is set in the same | |
3133 | way, but the breakpoint is automatically deleted after the first time your | |
79a6e687 | 3134 | program stops there. @xref{Disabling, ,Disabling Breakpoints}. |
c906108c | 3135 | |
c906108c | 3136 | @kindex hbreak |
ba04e063 | 3137 | @cindex hardware breakpoints |
c906108c | 3138 | @item hbreak @var{args} |
d4f3574e SS |
3139 | Set a hardware-assisted breakpoint. @var{args} are the same as for the |
3140 | @code{break} command and the breakpoint is set in the same way, but the | |
c906108c SS |
3141 | breakpoint requires hardware support and some target hardware may not |
3142 | have this support. The main purpose of this is EPROM/ROM code | |
d4f3574e SS |
3143 | debugging, so you can set a breakpoint at an instruction without |
3144 | changing the instruction. This can be used with the new trap-generation | |
09d4efe1 | 3145 | provided by SPARClite DSU and most x86-based targets. These targets |
d4f3574e SS |
3146 | will generate traps when a program accesses some data or instruction |
3147 | address that is assigned to the debug registers. However the hardware | |
3148 | breakpoint registers can take a limited number of breakpoints. For | |
3149 | example, on the DSU, only two data breakpoints can be set at a time, and | |
3150 | @value{GDBN} will reject this command if more than two are used. Delete | |
3151 | or disable unused hardware breakpoints before setting new ones | |
79a6e687 BW |
3152 | (@pxref{Disabling, ,Disabling Breakpoints}). |
3153 | @xref{Conditions, ,Break Conditions}. | |
9c16f35a EZ |
3154 | For remote targets, you can restrict the number of hardware |
3155 | breakpoints @value{GDBN} will use, see @ref{set remote | |
3156 | hardware-breakpoint-limit}. | |
501eef12 | 3157 | |
c906108c SS |
3158 | @kindex thbreak |
3159 | @item thbreak @var{args} | |
3160 | Set a hardware-assisted breakpoint enabled only for one stop. @var{args} | |
3161 | are the same as for the @code{hbreak} command and the breakpoint is set in | |
5d161b24 | 3162 | the same way. However, like the @code{tbreak} command, |
c906108c SS |
3163 | the breakpoint is automatically deleted after the |
3164 | first time your program stops there. Also, like the @code{hbreak} | |
5d161b24 | 3165 | command, the breakpoint requires hardware support and some target hardware |
79a6e687 BW |
3166 | may not have this support. @xref{Disabling, ,Disabling Breakpoints}. |
3167 | See also @ref{Conditions, ,Break Conditions}. | |
c906108c SS |
3168 | |
3169 | @kindex rbreak | |
3170 | @cindex regular expression | |
c45da7e6 EZ |
3171 | @cindex breakpoints in functions matching a regexp |
3172 | @cindex set breakpoints in many functions | |
c906108c | 3173 | @item rbreak @var{regex} |
c906108c | 3174 | Set breakpoints on all functions matching the regular expression |
11cf8741 JM |
3175 | @var{regex}. This command sets an unconditional breakpoint on all |
3176 | matches, printing a list of all breakpoints it set. Once these | |
3177 | breakpoints are set, they are treated just like the breakpoints set with | |
3178 | the @code{break} command. You can delete them, disable them, or make | |
3179 | them conditional the same way as any other breakpoint. | |
3180 | ||
3181 | The syntax of the regular expression is the standard one used with tools | |
3182 | like @file{grep}. Note that this is different from the syntax used by | |
3183 | shells, so for instance @code{foo*} matches all functions that include | |
3184 | an @code{fo} followed by zero or more @code{o}s. There is an implicit | |
3185 | @code{.*} leading and trailing the regular expression you supply, so to | |
3186 | match only functions that begin with @code{foo}, use @code{^foo}. | |
c906108c | 3187 | |
f7dc1244 | 3188 | @cindex non-member C@t{++} functions, set breakpoint in |
b37052ae | 3189 | When debugging C@t{++} programs, @code{rbreak} is useful for setting |
c906108c SS |
3190 | breakpoints on overloaded functions that are not members of any special |
3191 | classes. | |
c906108c | 3192 | |
f7dc1244 EZ |
3193 | @cindex set breakpoints on all functions |
3194 | The @code{rbreak} command can be used to set breakpoints in | |
3195 | @strong{all} the functions in a program, like this: | |
3196 | ||
3197 | @smallexample | |
3198 | (@value{GDBP}) rbreak . | |
3199 | @end smallexample | |
3200 | ||
c906108c SS |
3201 | @kindex info breakpoints |
3202 | @cindex @code{$_} and @code{info breakpoints} | |
3203 | @item info breakpoints @r{[}@var{n}@r{]} | |
3204 | @itemx info break @r{[}@var{n}@r{]} | |
3205 | @itemx info watchpoints @r{[}@var{n}@r{]} | |
3206 | Print a table of all breakpoints, watchpoints, and catchpoints set and | |
45ac1734 EZ |
3207 | not deleted. Optional argument @var{n} means print information only |
3208 | about the specified breakpoint (or watchpoint or catchpoint). For | |
3209 | each breakpoint, following columns are printed: | |
c906108c SS |
3210 | |
3211 | @table @emph | |
3212 | @item Breakpoint Numbers | |
3213 | @item Type | |
3214 | Breakpoint, watchpoint, or catchpoint. | |
3215 | @item Disposition | |
3216 | Whether the breakpoint is marked to be disabled or deleted when hit. | |
3217 | @item Enabled or Disabled | |
3218 | Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints | |
b3db7447 | 3219 | that are not enabled. |
c906108c | 3220 | @item Address |
fe6fbf8b | 3221 | Where the breakpoint is in your program, as a memory address. For a |
b3db7447 NR |
3222 | pending breakpoint whose address is not yet known, this field will |
3223 | contain @samp{<PENDING>}. Such breakpoint won't fire until a shared | |
3224 | library that has the symbol or line referred by breakpoint is loaded. | |
3225 | See below for details. A breakpoint with several locations will | |
3b784c4f | 3226 | have @samp{<MULTIPLE>} in this field---see below for details. |
c906108c SS |
3227 | @item What |
3228 | Where the breakpoint is in the source for your program, as a file and | |
2650777c JJ |
3229 | line number. For a pending breakpoint, the original string passed to |
3230 | the breakpoint command will be listed as it cannot be resolved until | |
3231 | the appropriate shared library is loaded in the future. | |
c906108c SS |
3232 | @end table |
3233 | ||
3234 | @noindent | |
3235 | If a breakpoint is conditional, @code{info break} shows the condition on | |
3236 | the line following the affected breakpoint; breakpoint commands, if any, | |
2650777c JJ |
3237 | are listed after that. A pending breakpoint is allowed to have a condition |
3238 | specified for it. The condition is not parsed for validity until a shared | |
3239 | library is loaded that allows the pending breakpoint to resolve to a | |
3240 | valid location. | |
c906108c SS |
3241 | |
3242 | @noindent | |
3243 | @code{info break} with a breakpoint | |
3244 | number @var{n} as argument lists only that breakpoint. The | |
3245 | convenience variable @code{$_} and the default examining-address for | |
3246 | the @code{x} command are set to the address of the last breakpoint | |
79a6e687 | 3247 | listed (@pxref{Memory, ,Examining Memory}). |
c906108c SS |
3248 | |
3249 | @noindent | |
3250 | @code{info break} displays a count of the number of times the breakpoint | |
3251 | has been hit. This is especially useful in conjunction with the | |
3252 | @code{ignore} command. You can ignore a large number of breakpoint | |
3253 | hits, look at the breakpoint info to see how many times the breakpoint | |
3254 | was hit, and then run again, ignoring one less than that number. This | |
3255 | will get you quickly to the last hit of that breakpoint. | |
3256 | @end table | |
3257 | ||
3258 | @value{GDBN} allows you to set any number of breakpoints at the same place in | |
3259 | your program. There is nothing silly or meaningless about this. When | |
3260 | the breakpoints are conditional, this is even useful | |
79a6e687 | 3261 | (@pxref{Conditions, ,Break Conditions}). |
c906108c | 3262 | |
2e9132cc EZ |
3263 | @cindex multiple locations, breakpoints |
3264 | @cindex breakpoints, multiple locations | |
fcda367b | 3265 | It is possible that a breakpoint corresponds to several locations |
fe6fbf8b VP |
3266 | in your program. Examples of this situation are: |
3267 | ||
3268 | @itemize @bullet | |
fe6fbf8b VP |
3269 | @item |
3270 | For a C@t{++} constructor, the @value{NGCC} compiler generates several | |
3271 | instances of the function body, used in different cases. | |
3272 | ||
3273 | @item | |
3274 | For a C@t{++} template function, a given line in the function can | |
3275 | correspond to any number of instantiations. | |
3276 | ||
3277 | @item | |
3278 | For an inlined function, a given source line can correspond to | |
3279 | several places where that function is inlined. | |
fe6fbf8b VP |
3280 | @end itemize |
3281 | ||
3282 | In all those cases, @value{GDBN} will insert a breakpoint at all | |
2e9132cc EZ |
3283 | the relevant locations@footnote{ |
3284 | As of this writing, multiple-location breakpoints work only if there's | |
3285 | line number information for all the locations. This means that they | |
3286 | will generally not work in system libraries, unless you have debug | |
3287 | info with line numbers for them.}. | |
fe6fbf8b | 3288 | |
3b784c4f EZ |
3289 | A breakpoint with multiple locations is displayed in the breakpoint |
3290 | table using several rows---one header row, followed by one row for | |
3291 | each breakpoint location. The header row has @samp{<MULTIPLE>} in the | |
3292 | address column. The rows for individual locations contain the actual | |
3293 | addresses for locations, and show the functions to which those | |
3294 | locations belong. The number column for a location is of the form | |
fe6fbf8b VP |
3295 | @var{breakpoint-number}.@var{location-number}. |
3296 | ||
3297 | For example: | |
3b784c4f | 3298 | |
fe6fbf8b VP |
3299 | @smallexample |
3300 | Num Type Disp Enb Address What | |
3301 | 1 breakpoint keep y <MULTIPLE> | |
3302 | stop only if i==1 | |
3303 | breakpoint already hit 1 time | |
3304 | 1.1 y 0x080486a2 in void foo<int>() at t.cc:8 | |
3305 | 1.2 y 0x080486ca in void foo<double>() at t.cc:8 | |
3306 | @end smallexample | |
3307 | ||
3308 | Each location can be individually enabled or disabled by passing | |
3309 | @var{breakpoint-number}.@var{location-number} as argument to the | |
3b784c4f EZ |
3310 | @code{enable} and @code{disable} commands. Note that you cannot |
3311 | delete the individual locations from the list, you can only delete the | |
16bfc218 | 3312 | entire list of locations that belong to their parent breakpoint (with |
3b784c4f EZ |
3313 | the @kbd{delete @var{num}} command, where @var{num} is the number of |
3314 | the parent breakpoint, 1 in the above example). Disabling or enabling | |
3315 | the parent breakpoint (@pxref{Disabling}) affects all of the locations | |
3316 | that belong to that breakpoint. | |
fe6fbf8b | 3317 | |
2650777c | 3318 | @cindex pending breakpoints |
fe6fbf8b | 3319 | It's quite common to have a breakpoint inside a shared library. |
3b784c4f | 3320 | Shared libraries can be loaded and unloaded explicitly, |
fe6fbf8b VP |
3321 | and possibly repeatedly, as the program is executed. To support |
3322 | this use case, @value{GDBN} updates breakpoint locations whenever | |
3323 | any shared library is loaded or unloaded. Typically, you would | |
fcda367b | 3324 | set a breakpoint in a shared library at the beginning of your |
fe6fbf8b VP |
3325 | debugging session, when the library is not loaded, and when the |
3326 | symbols from the library are not available. When you try to set | |
3327 | breakpoint, @value{GDBN} will ask you if you want to set | |
3b784c4f | 3328 | a so called @dfn{pending breakpoint}---breakpoint whose address |
fe6fbf8b VP |
3329 | is not yet resolved. |
3330 | ||
3331 | After the program is run, whenever a new shared library is loaded, | |
3332 | @value{GDBN} reevaluates all the breakpoints. When a newly loaded | |
3333 | shared library contains the symbol or line referred to by some | |
3334 | pending breakpoint, that breakpoint is resolved and becomes an | |
3335 | ordinary breakpoint. When a library is unloaded, all breakpoints | |
3336 | that refer to its symbols or source lines become pending again. | |
3337 | ||
3338 | This logic works for breakpoints with multiple locations, too. For | |
3339 | example, if you have a breakpoint in a C@t{++} template function, and | |
3340 | a newly loaded shared library has an instantiation of that template, | |
3341 | a new location is added to the list of locations for the breakpoint. | |
3342 | ||
3343 | Except for having unresolved address, pending breakpoints do not | |
3344 | differ from regular breakpoints. You can set conditions or commands, | |
3345 | enable and disable them and perform other breakpoint operations. | |
3346 | ||
3347 | @value{GDBN} provides some additional commands for controlling what | |
3348 | happens when the @samp{break} command cannot resolve breakpoint | |
3349 | address specification to an address: | |
dd79a6cf JJ |
3350 | |
3351 | @kindex set breakpoint pending | |
3352 | @kindex show breakpoint pending | |
3353 | @table @code | |
3354 | @item set breakpoint pending auto | |
3355 | This is the default behavior. When @value{GDBN} cannot find the breakpoint | |
3356 | location, it queries you whether a pending breakpoint should be created. | |
3357 | ||
3358 | @item set breakpoint pending on | |
3359 | This indicates that an unrecognized breakpoint location should automatically | |
3360 | result in a pending breakpoint being created. | |
3361 | ||
3362 | @item set breakpoint pending off | |
3363 | This indicates that pending breakpoints are not to be created. Any | |
3364 | unrecognized breakpoint location results in an error. This setting does | |
3365 | not affect any pending breakpoints previously created. | |
3366 | ||
3367 | @item show breakpoint pending | |
3368 | Show the current behavior setting for creating pending breakpoints. | |
3369 | @end table | |
2650777c | 3370 | |
fe6fbf8b VP |
3371 | The settings above only affect the @code{break} command and its |
3372 | variants. Once breakpoint is set, it will be automatically updated | |
3373 | as shared libraries are loaded and unloaded. | |
2650777c | 3374 | |
765dc015 VP |
3375 | @cindex automatic hardware breakpoints |
3376 | For some targets, @value{GDBN} can automatically decide if hardware or | |
3377 | software breakpoints should be used, depending on whether the | |
3378 | breakpoint address is read-only or read-write. This applies to | |
3379 | breakpoints set with the @code{break} command as well as to internal | |
3380 | breakpoints set by commands like @code{next} and @code{finish}. For | |
fcda367b | 3381 | breakpoints set with @code{hbreak}, @value{GDBN} will always use hardware |
765dc015 VP |
3382 | breakpoints. |
3383 | ||
3384 | You can control this automatic behaviour with the following commands:: | |
3385 | ||
3386 | @kindex set breakpoint auto-hw | |
3387 | @kindex show breakpoint auto-hw | |
3388 | @table @code | |
3389 | @item set breakpoint auto-hw on | |
3390 | This is the default behavior. When @value{GDBN} sets a breakpoint, it | |
3391 | will try to use the target memory map to decide if software or hardware | |
3392 | breakpoint must be used. | |
3393 | ||
3394 | @item set breakpoint auto-hw off | |
3395 | This indicates @value{GDBN} should not automatically select breakpoint | |
3396 | type. If the target provides a memory map, @value{GDBN} will warn when | |
3397 | trying to set software breakpoint at a read-only address. | |
3398 | @end table | |
3399 | ||
74960c60 VP |
3400 | @value{GDBN} normally implements breakpoints by replacing the program code |
3401 | at the breakpoint address with a special instruction, which, when | |
3402 | executed, given control to the debugger. By default, the program | |
3403 | code is so modified only when the program is resumed. As soon as | |
3404 | the program stops, @value{GDBN} restores the original instructions. This | |
3405 | behaviour guards against leaving breakpoints inserted in the | |
3406 | target should gdb abrubptly disconnect. However, with slow remote | |
3407 | targets, inserting and removing breakpoint can reduce the performance. | |
3408 | This behavior can be controlled with the following commands:: | |
3409 | ||
3410 | @kindex set breakpoint always-inserted | |
3411 | @kindex show breakpoint always-inserted | |
3412 | @table @code | |
3413 | @item set breakpoint always-inserted off | |
33e5cbd6 PA |
3414 | All breakpoints, including newly added by the user, are inserted in |
3415 | the target only when the target is resumed. All breakpoints are | |
3416 | removed from the target when it stops. | |
74960c60 VP |
3417 | |
3418 | @item set breakpoint always-inserted on | |
3419 | Causes all breakpoints to be inserted in the target at all times. If | |
3420 | the user adds a new breakpoint, or changes an existing breakpoint, the | |
3421 | breakpoints in the target are updated immediately. A breakpoint is | |
3422 | removed from the target only when breakpoint itself is removed. | |
33e5cbd6 PA |
3423 | |
3424 | @cindex non-stop mode, and @code{breakpoint always-inserted} | |
3425 | @item set breakpoint always-inserted auto | |
3426 | This is the default mode. If @value{GDBN} is controlling the inferior | |
3427 | in non-stop mode (@pxref{Non-Stop Mode}), gdb behaves as if | |
3428 | @code{breakpoint always-inserted} mode is on. If @value{GDBN} is | |
3429 | controlling the inferior in all-stop mode, @value{GDBN} behaves as if | |
3430 | @code{breakpoint always-inserted} mode is off. | |
74960c60 | 3431 | @end table |
765dc015 | 3432 | |
c906108c SS |
3433 | @cindex negative breakpoint numbers |
3434 | @cindex internal @value{GDBN} breakpoints | |
eb12ee30 AC |
3435 | @value{GDBN} itself sometimes sets breakpoints in your program for |
3436 | special purposes, such as proper handling of @code{longjmp} (in C | |
3437 | programs). These internal breakpoints are assigned negative numbers, | |
3438 | starting with @code{-1}; @samp{info breakpoints} does not display them. | |
c906108c | 3439 | You can see these breakpoints with the @value{GDBN} maintenance command |
eb12ee30 | 3440 | @samp{maint info breakpoints} (@pxref{maint info breakpoints}). |
c906108c SS |
3441 | |
3442 | ||
6d2ebf8b | 3443 | @node Set Watchpoints |
79a6e687 | 3444 | @subsection Setting Watchpoints |
c906108c SS |
3445 | |
3446 | @cindex setting watchpoints | |
c906108c SS |
3447 | You can use a watchpoint to stop execution whenever the value of an |
3448 | expression changes, without having to predict a particular place where | |
fd60e0df EZ |
3449 | this may happen. (This is sometimes called a @dfn{data breakpoint}.) |
3450 | The expression may be as simple as the value of a single variable, or | |
3451 | as complex as many variables combined by operators. Examples include: | |
3452 | ||
3453 | @itemize @bullet | |
3454 | @item | |
3455 | A reference to the value of a single variable. | |
3456 | ||
3457 | @item | |
3458 | An address cast to an appropriate data type. For example, | |
3459 | @samp{*(int *)0x12345678} will watch a 4-byte region at the specified | |
3460 | address (assuming an @code{int} occupies 4 bytes). | |
3461 | ||
3462 | @item | |
3463 | An arbitrarily complex expression, such as @samp{a*b + c/d}. The | |
3464 | expression can use any operators valid in the program's native | |
3465 | language (@pxref{Languages}). | |
3466 | @end itemize | |
c906108c | 3467 | |
fa4727a6 DJ |
3468 | You can set a watchpoint on an expression even if the expression can |
3469 | not be evaluated yet. For instance, you can set a watchpoint on | |
3470 | @samp{*global_ptr} before @samp{global_ptr} is initialized. | |
3471 | @value{GDBN} will stop when your program sets @samp{global_ptr} and | |
3472 | the expression produces a valid value. If the expression becomes | |
3473 | valid in some other way than changing a variable (e.g.@: if the memory | |
3474 | pointed to by @samp{*global_ptr} becomes readable as the result of a | |
3475 | @code{malloc} call), @value{GDBN} may not stop until the next time | |
3476 | the expression changes. | |
3477 | ||
82f2d802 EZ |
3478 | @cindex software watchpoints |
3479 | @cindex hardware watchpoints | |
c906108c | 3480 | Depending on your system, watchpoints may be implemented in software or |
2df3850c | 3481 | hardware. @value{GDBN} does software watchpointing by single-stepping your |
c906108c SS |
3482 | program and testing the variable's value each time, which is hundreds of |
3483 | times slower than normal execution. (But this may still be worth it, to | |
3484 | catch errors where you have no clue what part of your program is the | |
3485 | culprit.) | |
3486 | ||
37e4754d | 3487 | On some systems, such as HP-UX, PowerPC, @sc{gnu}/Linux and most other |
82f2d802 EZ |
3488 | x86-based targets, @value{GDBN} includes support for hardware |
3489 | watchpoints, which do not slow down the running of your program. | |
c906108c SS |
3490 | |
3491 | @table @code | |
3492 | @kindex watch | |
d8b2a693 | 3493 | @item watch @var{expr} @r{[}thread @var{threadnum}@r{]} |
fd60e0df EZ |
3494 | Set a watchpoint for an expression. @value{GDBN} will break when the |
3495 | expression @var{expr} is written into by the program and its value | |
3496 | changes. The simplest (and the most popular) use of this command is | |
3497 | to watch the value of a single variable: | |
3498 | ||
3499 | @smallexample | |
3500 | (@value{GDBP}) watch foo | |
3501 | @end smallexample | |
c906108c | 3502 | |
d8b2a693 JB |
3503 | If the command includes a @code{@r{[}thread @var{threadnum}@r{]}} |
3504 | clause, @value{GDBN} breaks only when the thread identified by | |
3505 | @var{threadnum} changes the value of @var{expr}. If any other threads | |
3506 | change the value of @var{expr}, @value{GDBN} will not break. Note | |
3507 | that watchpoints restricted to a single thread in this way only work | |
3508 | with Hardware Watchpoints. | |
3509 | ||
c906108c | 3510 | @kindex rwatch |
d8b2a693 | 3511 | @item rwatch @var{expr} @r{[}thread @var{threadnum}@r{]} |
09d4efe1 EZ |
3512 | Set a watchpoint that will break when the value of @var{expr} is read |
3513 | by the program. | |
c906108c SS |
3514 | |
3515 | @kindex awatch | |
d8b2a693 | 3516 | @item awatch @var{expr} @r{[}thread @var{threadnum}@r{]} |
09d4efe1 EZ |
3517 | Set a watchpoint that will break when @var{expr} is either read from |
3518 | or written into by the program. | |
c906108c | 3519 | |
45ac1734 | 3520 | @kindex info watchpoints @r{[}@var{n}@r{]} |
c906108c SS |
3521 | @item info watchpoints |
3522 | This command prints a list of watchpoints, breakpoints, and catchpoints; | |
09d4efe1 | 3523 | it is the same as @code{info break} (@pxref{Set Breaks}). |
c906108c SS |
3524 | @end table |
3525 | ||
3526 | @value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware | |
3527 | watchpoints execute very quickly, and the debugger reports a change in | |
3528 | value at the exact instruction where the change occurs. If @value{GDBN} | |
3529 | cannot set a hardware watchpoint, it sets a software watchpoint, which | |
3530 | executes more slowly and reports the change in value at the next | |
82f2d802 EZ |
3531 | @emph{statement}, not the instruction, after the change occurs. |
3532 | ||
82f2d802 EZ |
3533 | @cindex use only software watchpoints |
3534 | You can force @value{GDBN} to use only software watchpoints with the | |
3535 | @kbd{set can-use-hw-watchpoints 0} command. With this variable set to | |
3536 | zero, @value{GDBN} will never try to use hardware watchpoints, even if | |
3537 | the underlying system supports them. (Note that hardware-assisted | |
3538 | watchpoints that were set @emph{before} setting | |
3539 | @code{can-use-hw-watchpoints} to zero will still use the hardware | |
d3e8051b | 3540 | mechanism of watching expression values.) |
c906108c | 3541 | |
9c16f35a EZ |
3542 | @table @code |
3543 | @item set can-use-hw-watchpoints | |
3544 | @kindex set can-use-hw-watchpoints | |
3545 | Set whether or not to use hardware watchpoints. | |
3546 | ||
3547 | @item show can-use-hw-watchpoints | |
3548 | @kindex show can-use-hw-watchpoints | |
3549 | Show the current mode of using hardware watchpoints. | |
3550 | @end table | |
3551 | ||
3552 | For remote targets, you can restrict the number of hardware | |
3553 | watchpoints @value{GDBN} will use, see @ref{set remote | |
3554 | hardware-breakpoint-limit}. | |
3555 | ||
c906108c SS |
3556 | When you issue the @code{watch} command, @value{GDBN} reports |
3557 | ||
474c8240 | 3558 | @smallexample |
c906108c | 3559 | Hardware watchpoint @var{num}: @var{expr} |
474c8240 | 3560 | @end smallexample |
c906108c SS |
3561 | |
3562 | @noindent | |
3563 | if it was able to set a hardware watchpoint. | |
3564 | ||
7be570e7 JM |
3565 | Currently, the @code{awatch} and @code{rwatch} commands can only set |
3566 | hardware watchpoints, because accesses to data that don't change the | |
3567 | value of the watched expression cannot be detected without examining | |
3568 | every instruction as it is being executed, and @value{GDBN} does not do | |
3569 | that currently. If @value{GDBN} finds that it is unable to set a | |
3570 | hardware breakpoint with the @code{awatch} or @code{rwatch} command, it | |
3571 | will print a message like this: | |
3572 | ||
3573 | @smallexample | |
3574 | Expression cannot be implemented with read/access watchpoint. | |
3575 | @end smallexample | |
3576 | ||
3577 | Sometimes, @value{GDBN} cannot set a hardware watchpoint because the | |
3578 | data type of the watched expression is wider than what a hardware | |
3579 | watchpoint on the target machine can handle. For example, some systems | |
3580 | can only watch regions that are up to 4 bytes wide; on such systems you | |
3581 | cannot set hardware watchpoints for an expression that yields a | |
3582 | double-precision floating-point number (which is typically 8 bytes | |
3583 | wide). As a work-around, it might be possible to break the large region | |
3584 | into a series of smaller ones and watch them with separate watchpoints. | |
3585 | ||
3586 | If you set too many hardware watchpoints, @value{GDBN} might be unable | |
3587 | to insert all of them when you resume the execution of your program. | |
3588 | Since the precise number of active watchpoints is unknown until such | |
3589 | time as the program is about to be resumed, @value{GDBN} might not be | |
3590 | able to warn you about this when you set the watchpoints, and the | |
3591 | warning will be printed only when the program is resumed: | |
3592 | ||
3593 | @smallexample | |
3594 | Hardware watchpoint @var{num}: Could not insert watchpoint | |
3595 | @end smallexample | |
3596 | ||
3597 | @noindent | |
3598 | If this happens, delete or disable some of the watchpoints. | |
3599 | ||
fd60e0df EZ |
3600 | Watching complex expressions that reference many variables can also |
3601 | exhaust the resources available for hardware-assisted watchpoints. | |
3602 | That's because @value{GDBN} needs to watch every variable in the | |
3603 | expression with separately allocated resources. | |
3604 | ||
c906108c | 3605 | If you call a function interactively using @code{print} or @code{call}, |
2df3850c | 3606 | any watchpoints you have set will be inactive until @value{GDBN} reaches another |
c906108c SS |
3607 | kind of breakpoint or the call completes. |
3608 | ||
7be570e7 JM |
3609 | @value{GDBN} automatically deletes watchpoints that watch local |
3610 | (automatic) variables, or expressions that involve such variables, when | |
3611 | they go out of scope, that is, when the execution leaves the block in | |
3612 | which these variables were defined. In particular, when the program | |
3613 | being debugged terminates, @emph{all} local variables go out of scope, | |
3614 | and so only watchpoints that watch global variables remain set. If you | |
3615 | rerun the program, you will need to set all such watchpoints again. One | |
3616 | way of doing that would be to set a code breakpoint at the entry to the | |
3617 | @code{main} function and when it breaks, set all the watchpoints. | |
3618 | ||
c906108c SS |
3619 | @cindex watchpoints and threads |
3620 | @cindex threads and watchpoints | |
d983da9c DJ |
3621 | In multi-threaded programs, watchpoints will detect changes to the |
3622 | watched expression from every thread. | |
3623 | ||
3624 | @quotation | |
3625 | @emph{Warning:} In multi-threaded programs, software watchpoints | |
53a5351d JM |
3626 | have only limited usefulness. If @value{GDBN} creates a software |
3627 | watchpoint, it can only watch the value of an expression @emph{in a | |
3628 | single thread}. If you are confident that the expression can only | |
3629 | change due to the current thread's activity (and if you are also | |
3630 | confident that no other thread can become current), then you can use | |
3631 | software watchpoints as usual. However, @value{GDBN} may not notice | |
3632 | when a non-current thread's activity changes the expression. (Hardware | |
3633 | watchpoints, in contrast, watch an expression in all threads.) | |
c906108c | 3634 | @end quotation |
c906108c | 3635 | |
501eef12 AC |
3636 | @xref{set remote hardware-watchpoint-limit}. |
3637 | ||
6d2ebf8b | 3638 | @node Set Catchpoints |
79a6e687 | 3639 | @subsection Setting Catchpoints |
d4f3574e | 3640 | @cindex catchpoints, setting |
c906108c SS |
3641 | @cindex exception handlers |
3642 | @cindex event handling | |
3643 | ||
3644 | You can use @dfn{catchpoints} to cause the debugger to stop for certain | |
b37052ae | 3645 | kinds of program events, such as C@t{++} exceptions or the loading of a |
c906108c SS |
3646 | shared library. Use the @code{catch} command to set a catchpoint. |
3647 | ||
3648 | @table @code | |
3649 | @kindex catch | |
3650 | @item catch @var{event} | |
3651 | Stop when @var{event} occurs. @var{event} can be any of the following: | |
3652 | @table @code | |
3653 | @item throw | |
4644b6e3 | 3654 | @cindex stop on C@t{++} exceptions |
b37052ae | 3655 | The throwing of a C@t{++} exception. |
c906108c SS |
3656 | |
3657 | @item catch | |
b37052ae | 3658 | The catching of a C@t{++} exception. |
c906108c | 3659 | |
8936fcda JB |
3660 | @item exception |
3661 | @cindex Ada exception catching | |
3662 | @cindex catch Ada exceptions | |
3663 | An Ada exception being raised. If an exception name is specified | |
3664 | at the end of the command (eg @code{catch exception Program_Error}), | |
3665 | the debugger will stop only when this specific exception is raised. | |
3666 | Otherwise, the debugger stops execution when any Ada exception is raised. | |
3667 | ||
87f67dba JB |
3668 | When inserting an exception catchpoint on a user-defined exception whose |
3669 | name is identical to one of the exceptions defined by the language, the | |
3670 | fully qualified name must be used as the exception name. Otherwise, | |
3671 | @value{GDBN} will assume that it should stop on the pre-defined exception | |
3672 | rather than the user-defined one. For instance, assuming an exception | |
3673 | called @code{Constraint_Error} is defined in package @code{Pck}, then | |
3674 | the command to use to catch such exceptions is @kbd{catch exception | |
3675 | Pck.Constraint_Error}. | |
3676 | ||
8936fcda JB |
3677 | @item exception unhandled |
3678 | An exception that was raised but is not handled by the program. | |
3679 | ||
3680 | @item assert | |
3681 | A failed Ada assertion. | |
3682 | ||
c906108c | 3683 | @item exec |
4644b6e3 | 3684 | @cindex break on fork/exec |
5ee187d7 DJ |
3685 | A call to @code{exec}. This is currently only available for HP-UX |
3686 | and @sc{gnu}/Linux. | |
c906108c | 3687 | |
a96d9b2e SDJ |
3688 | @item syscall |
3689 | @itemx syscall @r{[}@var{name} @r{|} @var{number}@r{]} @r{...} | |
3690 | @cindex break on a system call. | |
3691 | A call to or return from a system call, a.k.a.@: @dfn{syscall}. A | |
3692 | syscall is a mechanism for application programs to request a service | |
3693 | from the operating system (OS) or one of the OS system services. | |
3694 | @value{GDBN} can catch some or all of the syscalls issued by the | |
3695 | debuggee, and show the related information for each syscall. If no | |
3696 | argument is specified, calls to and returns from all system calls | |
3697 | will be caught. | |
3698 | ||
3699 | @var{name} can be any system call name that is valid for the | |
3700 | underlying OS. Just what syscalls are valid depends on the OS. On | |
3701 | GNU and Unix systems, you can find the full list of valid syscall | |
3702 | names on @file{/usr/include/asm/unistd.h}. | |
3703 | ||
3704 | @c For MS-Windows, the syscall names and the corresponding numbers | |
3705 | @c can be found, e.g., on this URL: | |
3706 | @c http://www.metasploit.com/users/opcode/syscalls.html | |
3707 | @c but we don't support Windows syscalls yet. | |
3708 | ||
3709 | Normally, @value{GDBN} knows in advance which syscalls are valid for | |
3710 | each OS, so you can use the @value{GDBN} command-line completion | |
3711 | facilities (@pxref{Completion,, command completion}) to list the | |
3712 | available choices. | |
3713 | ||
3714 | You may also specify the system call numerically. A syscall's | |
3715 | number is the value passed to the OS's syscall dispatcher to | |
3716 | identify the requested service. When you specify the syscall by its | |
3717 | name, @value{GDBN} uses its database of syscalls to convert the name | |
3718 | into the corresponding numeric code, but using the number directly | |
3719 | may be useful if @value{GDBN}'s database does not have the complete | |
3720 | list of syscalls on your system (e.g., because @value{GDBN} lags | |
3721 | behind the OS upgrades). | |
3722 | ||
3723 | The example below illustrates how this command works if you don't provide | |
3724 | arguments to it: | |
3725 | ||
3726 | @smallexample | |
3727 | (@value{GDBP}) catch syscall | |
3728 | Catchpoint 1 (syscall) | |
3729 | (@value{GDBP}) r | |
3730 | Starting program: /tmp/catch-syscall | |
3731 | ||
3732 | Catchpoint 1 (call to syscall 'close'), \ | |
3733 | 0xffffe424 in __kernel_vsyscall () | |
3734 | (@value{GDBP}) c | |
3735 | Continuing. | |
3736 | ||
3737 | Catchpoint 1 (returned from syscall 'close'), \ | |
3738 | 0xffffe424 in __kernel_vsyscall () | |
3739 | (@value{GDBP}) | |
3740 | @end smallexample | |
3741 | ||
3742 | Here is an example of catching a system call by name: | |
3743 | ||
3744 | @smallexample | |
3745 | (@value{GDBP}) catch syscall chroot | |
3746 | Catchpoint 1 (syscall 'chroot' [61]) | |
3747 | (@value{GDBP}) r | |
3748 | Starting program: /tmp/catch-syscall | |
3749 | ||
3750 | Catchpoint 1 (call to syscall 'chroot'), \ | |
3751 | 0xffffe424 in __kernel_vsyscall () | |
3752 | (@value{GDBP}) c | |
3753 | Continuing. | |
3754 | ||
3755 | Catchpoint 1 (returned from syscall 'chroot'), \ | |
3756 | 0xffffe424 in __kernel_vsyscall () | |
3757 | (@value{GDBP}) | |
3758 | @end smallexample | |
3759 | ||
3760 | An example of specifying a system call numerically. In the case | |
3761 | below, the syscall number has a corresponding entry in the XML | |
3762 | file, so @value{GDBN} finds its name and prints it: | |
3763 | ||
3764 | @smallexample | |
3765 | (@value{GDBP}) catch syscall 252 | |
3766 | Catchpoint 1 (syscall(s) 'exit_group') | |
3767 | (@value{GDBP}) r | |
3768 | Starting program: /tmp/catch-syscall | |
3769 | ||
3770 | Catchpoint 1 (call to syscall 'exit_group'), \ | |
3771 | 0xffffe424 in __kernel_vsyscall () | |
3772 | (@value{GDBP}) c | |
3773 | Continuing. | |
3774 | ||
3775 | Program exited normally. | |
3776 | (@value{GDBP}) | |
3777 | @end smallexample | |
3778 | ||
3779 | However, there can be situations when there is no corresponding name | |
3780 | in XML file for that syscall number. In this case, @value{GDBN} prints | |
3781 | a warning message saying that it was not able to find the syscall name, | |
3782 | but the catchpoint will be set anyway. See the example below: | |
3783 | ||
3784 | @smallexample | |
3785 | (@value{GDBP}) catch syscall 764 | |
3786 | warning: The number '764' does not represent a known syscall. | |
3787 | Catchpoint 2 (syscall 764) | |
3788 | (@value{GDBP}) | |
3789 | @end smallexample | |
3790 | ||
3791 | If you configure @value{GDBN} using the @samp{--without-expat} option, | |
3792 | it will not be able to display syscall names. Also, if your | |
3793 | architecture does not have an XML file describing its system calls, | |
3794 | you will not be able to see the syscall names. It is important to | |
3795 | notice that these two features are used for accessing the syscall | |
3796 | name database. In either case, you will see a warning like this: | |
3797 | ||
3798 | @smallexample | |
3799 | (@value{GDBP}) catch syscall | |
3800 | warning: Could not open "syscalls/i386-linux.xml" | |
3801 | warning: Could not load the syscall XML file 'syscalls/i386-linux.xml'. | |
3802 | GDB will not be able to display syscall names. | |
3803 | Catchpoint 1 (syscall) | |
3804 | (@value{GDBP}) | |
3805 | @end smallexample | |
3806 | ||
3807 | Of course, the file name will change depending on your architecture and system. | |
3808 | ||
3809 | Still using the example above, you can also try to catch a syscall by its | |
3810 | number. In this case, you would see something like: | |
3811 | ||
3812 | @smallexample | |
3813 | (@value{GDBP}) catch syscall 252 | |
3814 | Catchpoint 1 (syscall(s) 252) | |
3815 | @end smallexample | |
3816 | ||
3817 | Again, in this case @value{GDBN} would not be able to display syscall's names. | |
3818 | ||
c906108c | 3819 | @item fork |
5ee187d7 DJ |
3820 | A call to @code{fork}. This is currently only available for HP-UX |
3821 | and @sc{gnu}/Linux. | |
c906108c SS |
3822 | |
3823 | @item vfork | |
5ee187d7 DJ |
3824 | A call to @code{vfork}. This is currently only available for HP-UX |
3825 | and @sc{gnu}/Linux. | |
c906108c | 3826 | |
c906108c SS |
3827 | @end table |
3828 | ||
3829 | @item tcatch @var{event} | |
3830 | Set a catchpoint that is enabled only for one stop. The catchpoint is | |
3831 | automatically deleted after the first time the event is caught. | |
3832 | ||
3833 | @end table | |
3834 | ||
3835 | Use the @code{info break} command to list the current catchpoints. | |
3836 | ||
b37052ae | 3837 | There are currently some limitations to C@t{++} exception handling |
c906108c SS |
3838 | (@code{catch throw} and @code{catch catch}) in @value{GDBN}: |
3839 | ||
3840 | @itemize @bullet | |
3841 | @item | |
3842 | If you call a function interactively, @value{GDBN} normally returns | |
3843 | control to you when the function has finished executing. If the call | |
3844 | raises an exception, however, the call may bypass the mechanism that | |
3845 | returns control to you and cause your program either to abort or to | |
3846 | simply continue running until it hits a breakpoint, catches a signal | |
3847 | that @value{GDBN} is listening for, or exits. This is the case even if | |
3848 | you set a catchpoint for the exception; catchpoints on exceptions are | |
3849 | disabled within interactive calls. | |
3850 | ||
3851 | @item | |
3852 | You cannot raise an exception interactively. | |
3853 | ||
3854 | @item | |
3855 | You cannot install an exception handler interactively. | |
3856 | @end itemize | |
3857 | ||
3858 | @cindex raise exceptions | |
3859 | Sometimes @code{catch} is not the best way to debug exception handling: | |
3860 | if you need to know exactly where an exception is raised, it is better to | |
3861 | stop @emph{before} the exception handler is called, since that way you | |
3862 | can see the stack before any unwinding takes place. If you set a | |
3863 | breakpoint in an exception handler instead, it may not be easy to find | |
3864 | out where the exception was raised. | |
3865 | ||
3866 | To stop just before an exception handler is called, you need some | |
b37052ae | 3867 | knowledge of the implementation. In the case of @sc{gnu} C@t{++}, exceptions are |
c906108c SS |
3868 | raised by calling a library function named @code{__raise_exception} |
3869 | which has the following ANSI C interface: | |
3870 | ||
474c8240 | 3871 | @smallexample |
c906108c | 3872 | /* @var{addr} is where the exception identifier is stored. |
d4f3574e SS |
3873 | @var{id} is the exception identifier. */ |
3874 | void __raise_exception (void **addr, void *id); | |
474c8240 | 3875 | @end smallexample |
c906108c SS |
3876 | |
3877 | @noindent | |
3878 | To make the debugger catch all exceptions before any stack | |
3879 | unwinding takes place, set a breakpoint on @code{__raise_exception} | |
79a6e687 | 3880 | (@pxref{Breakpoints, ,Breakpoints; Watchpoints; and Exceptions}). |
c906108c | 3881 | |
79a6e687 | 3882 | With a conditional breakpoint (@pxref{Conditions, ,Break Conditions}) |
c906108c SS |
3883 | that depends on the value of @var{id}, you can stop your program when |
3884 | a specific exception is raised. You can use multiple conditional | |
3885 | breakpoints to stop your program when any of a number of exceptions are | |
3886 | raised. | |
3887 | ||
3888 | ||
6d2ebf8b | 3889 | @node Delete Breaks |
79a6e687 | 3890 | @subsection Deleting Breakpoints |
c906108c SS |
3891 | |
3892 | @cindex clearing breakpoints, watchpoints, catchpoints | |
3893 | @cindex deleting breakpoints, watchpoints, catchpoints | |
3894 | It is often necessary to eliminate a breakpoint, watchpoint, or | |
3895 | catchpoint once it has done its job and you no longer want your program | |
3896 | to stop there. This is called @dfn{deleting} the breakpoint. A | |
3897 | breakpoint that has been deleted no longer exists; it is forgotten. | |
3898 | ||
3899 | With the @code{clear} command you can delete breakpoints according to | |
3900 | where they are in your program. With the @code{delete} command you can | |
3901 | delete individual breakpoints, watchpoints, or catchpoints by specifying | |
3902 | their breakpoint numbers. | |
3903 | ||
3904 | It is not necessary to delete a breakpoint to proceed past it. @value{GDBN} | |
3905 | automatically ignores breakpoints on the first instruction to be executed | |
3906 | when you continue execution without changing the execution address. | |
3907 | ||
3908 | @table @code | |
3909 | @kindex clear | |
3910 | @item clear | |
3911 | Delete any breakpoints at the next instruction to be executed in the | |
79a6e687 | 3912 | selected stack frame (@pxref{Selection, ,Selecting a Frame}). When |
c906108c SS |
3913 | the innermost frame is selected, this is a good way to delete a |
3914 | breakpoint where your program just stopped. | |
3915 | ||
2a25a5ba EZ |
3916 | @item clear @var{location} |
3917 | Delete any breakpoints set at the specified @var{location}. | |
3918 | @xref{Specify Location}, for the various forms of @var{location}; the | |
3919 | most useful ones are listed below: | |
3920 | ||
3921 | @table @code | |
c906108c SS |
3922 | @item clear @var{function} |
3923 | @itemx clear @var{filename}:@var{function} | |
09d4efe1 | 3924 | Delete any breakpoints set at entry to the named @var{function}. |
c906108c SS |
3925 | |
3926 | @item clear @var{linenum} | |
3927 | @itemx clear @var{filename}:@var{linenum} | |
09d4efe1 EZ |
3928 | Delete any breakpoints set at or within the code of the specified |
3929 | @var{linenum} of the specified @var{filename}. | |
2a25a5ba | 3930 | @end table |
c906108c SS |
3931 | |
3932 | @cindex delete breakpoints | |
3933 | @kindex delete | |
41afff9a | 3934 | @kindex d @r{(@code{delete})} |
c5394b80 JM |
3935 | @item delete @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
3936 | Delete the breakpoints, watchpoints, or catchpoints of the breakpoint | |
3937 | ranges specified as arguments. If no argument is specified, delete all | |
c906108c SS |
3938 | breakpoints (@value{GDBN} asks confirmation, unless you have @code{set |
3939 | confirm off}). You can abbreviate this command as @code{d}. | |
3940 | @end table | |
3941 | ||
6d2ebf8b | 3942 | @node Disabling |
79a6e687 | 3943 | @subsection Disabling Breakpoints |
c906108c | 3944 | |
4644b6e3 | 3945 | @cindex enable/disable a breakpoint |
c906108c SS |
3946 | Rather than deleting a breakpoint, watchpoint, or catchpoint, you might |
3947 | prefer to @dfn{disable} it. This makes the breakpoint inoperative as if | |
3948 | it had been deleted, but remembers the information on the breakpoint so | |
3949 | that you can @dfn{enable} it again later. | |
3950 | ||
3951 | You disable and enable breakpoints, watchpoints, and catchpoints with | |
3952 | the @code{enable} and @code{disable} commands, optionally specifying one | |
3953 | or more breakpoint numbers as arguments. Use @code{info break} or | |
3954 | @code{info watch} to print a list of breakpoints, watchpoints, and | |
3955 | catchpoints if you do not know which numbers to use. | |
3956 | ||
3b784c4f EZ |
3957 | Disabling and enabling a breakpoint that has multiple locations |
3958 | affects all of its locations. | |
3959 | ||
c906108c SS |
3960 | A breakpoint, watchpoint, or catchpoint can have any of four different |
3961 | states of enablement: | |
3962 | ||
3963 | @itemize @bullet | |
3964 | @item | |
3965 | Enabled. The breakpoint stops your program. A breakpoint set | |
3966 | with the @code{break} command starts out in this state. | |
3967 | @item | |
3968 | Disabled. The breakpoint has no effect on your program. | |
3969 | @item | |
3970 | Enabled once. The breakpoint stops your program, but then becomes | |
d4f3574e | 3971 | disabled. |
c906108c SS |
3972 | @item |
3973 | Enabled for deletion. The breakpoint stops your program, but | |
d4f3574e SS |
3974 | immediately after it does so it is deleted permanently. A breakpoint |
3975 | set with the @code{tbreak} command starts out in this state. | |
c906108c SS |
3976 | @end itemize |
3977 | ||
3978 | You can use the following commands to enable or disable breakpoints, | |
3979 | watchpoints, and catchpoints: | |
3980 | ||
3981 | @table @code | |
c906108c | 3982 | @kindex disable |
41afff9a | 3983 | @kindex dis @r{(@code{disable})} |
c5394b80 | 3984 | @item disable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
3985 | Disable the specified breakpoints---or all breakpoints, if none are |
3986 | listed. A disabled breakpoint has no effect but is not forgotten. All | |
3987 | options such as ignore-counts, conditions and commands are remembered in | |
3988 | case the breakpoint is enabled again later. You may abbreviate | |
3989 | @code{disable} as @code{dis}. | |
3990 | ||
c906108c | 3991 | @kindex enable |
c5394b80 | 3992 | @item enable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]} |
c906108c SS |
3993 | Enable the specified breakpoints (or all defined breakpoints). They |
3994 | become effective once again in stopping your program. | |
3995 | ||
c5394b80 | 3996 | @item enable @r{[}breakpoints@r{]} once @var{range}@dots{} |
c906108c SS |
3997 | Enable the specified breakpoints temporarily. @value{GDBN} disables any |
3998 | of these breakpoints immediately after stopping your program. | |
3999 | ||
c5394b80 | 4000 | @item enable @r{[}breakpoints@r{]} delete @var{range}@dots{} |
c906108c SS |
4001 | Enable the specified breakpoints to work once, then die. @value{GDBN} |
4002 | deletes any of these breakpoints as soon as your program stops there. | |
09d4efe1 | 4003 | Breakpoints set by the @code{tbreak} command start out in this state. |
c906108c SS |
4004 | @end table |
4005 | ||
d4f3574e SS |
4006 | @c FIXME: I think the following ``Except for [...] @code{tbreak}'' is |
4007 | @c confusing: tbreak is also initially enabled. | |
c906108c | 4008 | Except for a breakpoint set with @code{tbreak} (@pxref{Set Breaks, |
79a6e687 | 4009 | ,Setting Breakpoints}), breakpoints that you set are initially enabled; |
c906108c SS |
4010 | subsequently, they become disabled or enabled only when you use one of |
4011 | the commands above. (The command @code{until} can set and delete a | |
4012 | breakpoint of its own, but it does not change the state of your other | |
4013 | breakpoints; see @ref{Continuing and Stepping, ,Continuing and | |
79a6e687 | 4014 | Stepping}.) |
c906108c | 4015 | |
6d2ebf8b | 4016 | @node Conditions |
79a6e687 | 4017 | @subsection Break Conditions |
c906108c SS |
4018 | @cindex conditional breakpoints |
4019 | @cindex breakpoint conditions | |
4020 | ||
4021 | @c FIXME what is scope of break condition expr? Context where wanted? | |
5d161b24 | 4022 | @c in particular for a watchpoint? |
c906108c SS |
4023 | The simplest sort of breakpoint breaks every time your program reaches a |
4024 | specified place. You can also specify a @dfn{condition} for a | |
4025 | breakpoint. A condition is just a Boolean expression in your | |
4026 | programming language (@pxref{Expressions, ,Expressions}). A breakpoint with | |
4027 | a condition evaluates the expression each time your program reaches it, | |
4028 | and your program stops only if the condition is @emph{true}. | |
4029 | ||
4030 | This is the converse of using assertions for program validation; in that | |
4031 | situation, you want to stop when the assertion is violated---that is, | |
4032 | when the condition is false. In C, if you want to test an assertion expressed | |
4033 | by the condition @var{assert}, you should set the condition | |
4034 | @samp{! @var{assert}} on the appropriate breakpoint. | |
4035 | ||
4036 | Conditions are also accepted for watchpoints; you may not need them, | |
4037 | since a watchpoint is inspecting the value of an expression anyhow---but | |
4038 | it might be simpler, say, to just set a watchpoint on a variable name, | |
4039 | and specify a condition that tests whether the new value is an interesting | |
4040 | one. | |
4041 | ||
4042 | Break conditions can have side effects, and may even call functions in | |
4043 | your program. This can be useful, for example, to activate functions | |
4044 | that log program progress, or to use your own print functions to | |
99e008fe | 4045 | format special data structures. The effects are completely predictable |
c906108c SS |
4046 | unless there is another enabled breakpoint at the same address. (In |
4047 | that case, @value{GDBN} might see the other breakpoint first and stop your | |
4048 | program without checking the condition of this one.) Note that | |
d4f3574e SS |
4049 | breakpoint commands are usually more convenient and flexible than break |
4050 | conditions for the | |
c906108c | 4051 | purpose of performing side effects when a breakpoint is reached |
79a6e687 | 4052 | (@pxref{Break Commands, ,Breakpoint Command Lists}). |
c906108c SS |
4053 | |
4054 | Break conditions can be specified when a breakpoint is set, by using | |
4055 | @samp{if} in the arguments to the @code{break} command. @xref{Set | |
79a6e687 | 4056 | Breaks, ,Setting Breakpoints}. They can also be changed at any time |
c906108c | 4057 | with the @code{condition} command. |
53a5351d | 4058 | |
c906108c SS |
4059 | You can also use the @code{if} keyword with the @code{watch} command. |
4060 | The @code{catch} command does not recognize the @code{if} keyword; | |
4061 | @code{condition} is the only way to impose a further condition on a | |
4062 | catchpoint. | |
c906108c SS |
4063 | |
4064 | @table @code | |
4065 | @kindex condition | |
4066 | @item condition @var{bnum} @var{expression} | |
4067 | Specify @var{expression} as the break condition for breakpoint, | |
4068 | watchpoint, or catchpoint number @var{bnum}. After you set a condition, | |
4069 | breakpoint @var{bnum} stops your program only if the value of | |
4070 | @var{expression} is true (nonzero, in C). When you use | |
4071 | @code{condition}, @value{GDBN} checks @var{expression} immediately for | |
4072 | syntactic correctness, and to determine whether symbols in it have | |
d4f3574e SS |
4073 | referents in the context of your breakpoint. If @var{expression} uses |
4074 | symbols not referenced in the context of the breakpoint, @value{GDBN} | |
4075 | prints an error message: | |
4076 | ||
474c8240 | 4077 | @smallexample |
d4f3574e | 4078 | No symbol "foo" in current context. |
474c8240 | 4079 | @end smallexample |
d4f3574e SS |
4080 | |
4081 | @noindent | |
c906108c SS |
4082 | @value{GDBN} does |
4083 | not actually evaluate @var{expression} at the time the @code{condition} | |
d4f3574e SS |
4084 | command (or a command that sets a breakpoint with a condition, like |
4085 | @code{break if @dots{}}) is given, however. @xref{Expressions, ,Expressions}. | |
c906108c SS |
4086 | |
4087 | @item condition @var{bnum} | |
4088 | Remove the condition from breakpoint number @var{bnum}. It becomes | |
4089 | an ordinary unconditional breakpoint. | |
4090 | @end table | |
4091 | ||
4092 | @cindex ignore count (of breakpoint) | |
4093 | A special case of a breakpoint condition is to stop only when the | |
4094 | breakpoint has been reached a certain number of times. This is so | |
4095 | useful that there is a special way to do it, using the @dfn{ignore | |
4096 | count} of the breakpoint. Every breakpoint has an ignore count, which | |
4097 | is an integer. Most of the time, the ignore count is zero, and | |
4098 | therefore has no effect. But if your program reaches a breakpoint whose | |
4099 | ignore count is positive, then instead of stopping, it just decrements | |
4100 | the ignore count by one and continues. As a result, if the ignore count | |
4101 | value is @var{n}, the breakpoint does not stop the next @var{n} times | |
4102 | your program reaches it. | |
4103 | ||
4104 | @table @code | |
4105 | @kindex ignore | |
4106 | @item ignore @var{bnum} @var{count} | |
4107 | Set the ignore count of breakpoint number @var{bnum} to @var{count}. | |
4108 | The next @var{count} times the breakpoint is reached, your program's | |
4109 | execution does not stop; other than to decrement the ignore count, @value{GDBN} | |
4110 | takes no action. | |
4111 | ||
4112 | To make the breakpoint stop the next time it is reached, specify | |
4113 | a count of zero. | |
4114 | ||
4115 | When you use @code{continue} to resume execution of your program from a | |
4116 | breakpoint, you can specify an ignore count directly as an argument to | |
4117 | @code{continue}, rather than using @code{ignore}. @xref{Continuing and | |
79a6e687 | 4118 | Stepping,,Continuing and Stepping}. |
c906108c SS |
4119 | |
4120 | If a breakpoint has a positive ignore count and a condition, the | |
4121 | condition is not checked. Once the ignore count reaches zero, | |
4122 | @value{GDBN} resumes checking the condition. | |
4123 | ||
4124 | You could achieve the effect of the ignore count with a condition such | |
4125 | as @w{@samp{$foo-- <= 0}} using a debugger convenience variable that | |
4126 | is decremented each time. @xref{Convenience Vars, ,Convenience | |
79a6e687 | 4127 | Variables}. |
c906108c SS |
4128 | @end table |
4129 | ||
4130 | Ignore counts apply to breakpoints, watchpoints, and catchpoints. | |
4131 | ||
4132 | ||
6d2ebf8b | 4133 | @node Break Commands |
79a6e687 | 4134 | @subsection Breakpoint Command Lists |
c906108c SS |
4135 | |
4136 | @cindex breakpoint commands | |
4137 | You can give any breakpoint (or watchpoint or catchpoint) a series of | |
4138 | commands to execute when your program stops due to that breakpoint. For | |
4139 | example, you might want to print the values of certain expressions, or | |
4140 | enable other breakpoints. | |
4141 | ||
4142 | @table @code | |
4143 | @kindex commands | |
ca91424e | 4144 | @kindex end@r{ (breakpoint commands)} |
c906108c SS |
4145 | @item commands @r{[}@var{bnum}@r{]} |
4146 | @itemx @dots{} @var{command-list} @dots{} | |
4147 | @itemx end | |
4148 | Specify a list of commands for breakpoint number @var{bnum}. The commands | |
4149 | themselves appear on the following lines. Type a line containing just | |
4150 | @code{end} to terminate the commands. | |
4151 | ||
4152 | To remove all commands from a breakpoint, type @code{commands} and | |
4153 | follow it immediately with @code{end}; that is, give no commands. | |
4154 | ||
4155 | With no @var{bnum} argument, @code{commands} refers to the last | |
4156 | breakpoint, watchpoint, or catchpoint set (not to the breakpoint most | |
4157 | recently encountered). | |
4158 | @end table | |
4159 | ||
4160 | Pressing @key{RET} as a means of repeating the last @value{GDBN} command is | |
4161 | disabled within a @var{command-list}. | |
4162 | ||
4163 | You can use breakpoint commands to start your program up again. Simply | |
4164 | use the @code{continue} command, or @code{step}, or any other command | |
4165 | that resumes execution. | |
4166 | ||
4167 | Any other commands in the command list, after a command that resumes | |
4168 | execution, are ignored. This is because any time you resume execution | |
4169 | (even with a simple @code{next} or @code{step}), you may encounter | |
4170 | another breakpoint---which could have its own command list, leading to | |
4171 | ambiguities about which list to execute. | |
4172 | ||
4173 | @kindex silent | |
4174 | If the first command you specify in a command list is @code{silent}, the | |
4175 | usual message about stopping at a breakpoint is not printed. This may | |
4176 | be desirable for breakpoints that are to print a specific message and | |
4177 | then continue. If none of the remaining commands print anything, you | |
4178 | see no sign that the breakpoint was reached. @code{silent} is | |
4179 | meaningful only at the beginning of a breakpoint command list. | |
4180 | ||
4181 | The commands @code{echo}, @code{output}, and @code{printf} allow you to | |
4182 | print precisely controlled output, and are often useful in silent | |
79a6e687 | 4183 | breakpoints. @xref{Output, ,Commands for Controlled Output}. |
c906108c SS |
4184 | |
4185 | For example, here is how you could use breakpoint commands to print the | |
4186 | value of @code{x} at entry to @code{foo} whenever @code{x} is positive. | |
4187 | ||
474c8240 | 4188 | @smallexample |
c906108c SS |
4189 | break foo if x>0 |
4190 | commands | |
4191 | silent | |
4192 | printf "x is %d\n",x | |
4193 | cont | |
4194 | end | |
474c8240 | 4195 | @end smallexample |
c906108c SS |
4196 | |
4197 | One application for breakpoint commands is to compensate for one bug so | |
4198 | you can test for another. Put a breakpoint just after the erroneous line | |
4199 | of code, give it a condition to detect the case in which something | |
4200 | erroneous has been done, and give it commands to assign correct values | |
4201 | to any variables that need them. End with the @code{continue} command | |
4202 | so that your program does not stop, and start with the @code{silent} | |
4203 | command so that no output is produced. Here is an example: | |
4204 | ||
474c8240 | 4205 | @smallexample |
c906108c SS |
4206 | break 403 |
4207 | commands | |
4208 | silent | |
4209 | set x = y + 4 | |
4210 | cont | |
4211 | end | |
474c8240 | 4212 | @end smallexample |
c906108c | 4213 | |
c906108c | 4214 | @c @ifclear BARETARGET |
6d2ebf8b | 4215 | @node Error in Breakpoints |
d4f3574e | 4216 | @subsection ``Cannot insert breakpoints'' |
c906108c | 4217 | |
fa3a767f PA |
4218 | If you request too many active hardware-assisted breakpoints and |
4219 | watchpoints, you will see this error message: | |
d4f3574e SS |
4220 | |
4221 | @c FIXME: the precise wording of this message may change; the relevant | |
4222 | @c source change is not committed yet (Sep 3, 1999). | |
4223 | @smallexample | |
4224 | Stopped; cannot insert breakpoints. | |
4225 | You may have requested too many hardware breakpoints and watchpoints. | |
4226 | @end smallexample | |
4227 | ||
4228 | @noindent | |
4229 | This message is printed when you attempt to resume the program, since | |
4230 | only then @value{GDBN} knows exactly how many hardware breakpoints and | |
4231 | watchpoints it needs to insert. | |
4232 | ||
4233 | When this message is printed, you need to disable or remove some of the | |
4234 | hardware-assisted breakpoints and watchpoints, and then continue. | |
4235 | ||
79a6e687 | 4236 | @node Breakpoint-related Warnings |
1485d690 KB |
4237 | @subsection ``Breakpoint address adjusted...'' |
4238 | @cindex breakpoint address adjusted | |
4239 | ||
4240 | Some processor architectures place constraints on the addresses at | |
4241 | which breakpoints may be placed. For architectures thus constrained, | |
4242 | @value{GDBN} will attempt to adjust the breakpoint's address to comply | |
4243 | with the constraints dictated by the architecture. | |
4244 | ||
4245 | One example of such an architecture is the Fujitsu FR-V. The FR-V is | |
4246 | a VLIW architecture in which a number of RISC-like instructions may be | |
4247 | bundled together for parallel execution. The FR-V architecture | |
4248 | constrains the location of a breakpoint instruction within such a | |
4249 | bundle to the instruction with the lowest address. @value{GDBN} | |
4250 | honors this constraint by adjusting a breakpoint's address to the | |
4251 | first in the bundle. | |
4252 | ||
4253 | It is not uncommon for optimized code to have bundles which contain | |
4254 | instructions from different source statements, thus it may happen that | |
4255 | a breakpoint's address will be adjusted from one source statement to | |
4256 | another. Since this adjustment may significantly alter @value{GDBN}'s | |
4257 | breakpoint related behavior from what the user expects, a warning is | |
4258 | printed when the breakpoint is first set and also when the breakpoint | |
4259 | is hit. | |
4260 | ||
4261 | A warning like the one below is printed when setting a breakpoint | |
4262 | that's been subject to address adjustment: | |
4263 | ||
4264 | @smallexample | |
4265 | warning: Breakpoint address adjusted from 0x00010414 to 0x00010410. | |
4266 | @end smallexample | |
4267 | ||
4268 | Such warnings are printed both for user settable and @value{GDBN}'s | |
4269 | internal breakpoints. If you see one of these warnings, you should | |
4270 | verify that a breakpoint set at the adjusted address will have the | |
4271 | desired affect. If not, the breakpoint in question may be removed and | |
b383017d | 4272 | other breakpoints may be set which will have the desired behavior. |
1485d690 KB |
4273 | E.g., it may be sufficient to place the breakpoint at a later |
4274 | instruction. A conditional breakpoint may also be useful in some | |
4275 | cases to prevent the breakpoint from triggering too often. | |
4276 | ||
4277 | @value{GDBN} will also issue a warning when stopping at one of these | |
4278 | adjusted breakpoints: | |
4279 | ||
4280 | @smallexample | |
4281 | warning: Breakpoint 1 address previously adjusted from 0x00010414 | |
4282 | to 0x00010410. | |
4283 | @end smallexample | |
4284 | ||
4285 | When this warning is encountered, it may be too late to take remedial | |
4286 | action except in cases where the breakpoint is hit earlier or more | |
4287 | frequently than expected. | |
d4f3574e | 4288 | |
6d2ebf8b | 4289 | @node Continuing and Stepping |
79a6e687 | 4290 | @section Continuing and Stepping |
c906108c SS |
4291 | |
4292 | @cindex stepping | |
4293 | @cindex continuing | |
4294 | @cindex resuming execution | |
4295 | @dfn{Continuing} means resuming program execution until your program | |
4296 | completes normally. In contrast, @dfn{stepping} means executing just | |
4297 | one more ``step'' of your program, where ``step'' may mean either one | |
4298 | line of source code, or one machine instruction (depending on what | |
7a292a7a SS |
4299 | particular command you use). Either when continuing or when stepping, |
4300 | your program may stop even sooner, due to a breakpoint or a signal. (If | |
d4f3574e SS |
4301 | it stops due to a signal, you may want to use @code{handle}, or use |
4302 | @samp{signal 0} to resume execution. @xref{Signals, ,Signals}.) | |
c906108c SS |
4303 | |
4304 | @table @code | |
4305 | @kindex continue | |
41afff9a EZ |
4306 | @kindex c @r{(@code{continue})} |
4307 | @kindex fg @r{(resume foreground execution)} | |
c906108c SS |
4308 | @item continue @r{[}@var{ignore-count}@r{]} |
4309 | @itemx c @r{[}@var{ignore-count}@r{]} | |
4310 | @itemx fg @r{[}@var{ignore-count}@r{]} | |
4311 | Resume program execution, at the address where your program last stopped; | |
4312 | any breakpoints set at that address are bypassed. The optional argument | |
4313 | @var{ignore-count} allows you to specify a further number of times to | |
4314 | ignore a breakpoint at this location; its effect is like that of | |
79a6e687 | 4315 | @code{ignore} (@pxref{Conditions, ,Break Conditions}). |
c906108c SS |
4316 | |
4317 | The argument @var{ignore-count} is meaningful only when your program | |
4318 | stopped due to a breakpoint. At other times, the argument to | |
4319 | @code{continue} is ignored. | |
4320 | ||
d4f3574e SS |
4321 | The synonyms @code{c} and @code{fg} (for @dfn{foreground}, as the |
4322 | debugged program is deemed to be the foreground program) are provided | |
4323 | purely for convenience, and have exactly the same behavior as | |
4324 | @code{continue}. | |
c906108c SS |
4325 | @end table |
4326 | ||
4327 | To resume execution at a different place, you can use @code{return} | |
79a6e687 | 4328 | (@pxref{Returning, ,Returning from a Function}) to go back to the |
c906108c | 4329 | calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a |
79a6e687 | 4330 | Different Address}) to go to an arbitrary location in your program. |
c906108c SS |
4331 | |
4332 | A typical technique for using stepping is to set a breakpoint | |
79a6e687 | 4333 | (@pxref{Breakpoints, ,Breakpoints; Watchpoints; and Catchpoints}) at the |
c906108c SS |
4334 | beginning of the function or the section of your program where a problem |
4335 | is believed to lie, run your program until it stops at that breakpoint, | |
4336 | and then step through the suspect area, examining the variables that are | |
4337 | interesting, until you see the problem happen. | |
4338 | ||
4339 | @table @code | |
4340 | @kindex step | |
41afff9a | 4341 | @kindex s @r{(@code{step})} |
c906108c SS |
4342 | @item step |
4343 | Continue running your program until control reaches a different source | |
4344 | line, then stop it and return control to @value{GDBN}. This command is | |
4345 | abbreviated @code{s}. | |
4346 | ||
4347 | @quotation | |
4348 | @c "without debugging information" is imprecise; actually "without line | |
4349 | @c numbers in the debugging information". (gcc -g1 has debugging info but | |
4350 | @c not line numbers). But it seems complex to try to make that | |
4351 | @c distinction here. | |
4352 | @emph{Warning:} If you use the @code{step} command while control is | |
4353 | within a function that was compiled without debugging information, | |
4354 | execution proceeds until control reaches a function that does have | |
4355 | debugging information. Likewise, it will not step into a function which | |
4356 | is compiled without debugging information. To step through functions | |
4357 | without debugging information, use the @code{stepi} command, described | |
4358 | below. | |
4359 | @end quotation | |
4360 | ||
4a92d011 EZ |
4361 | The @code{step} command only stops at the first instruction of a source |
4362 | line. This prevents the multiple stops that could otherwise occur in | |
4363 | @code{switch} statements, @code{for} loops, etc. @code{step} continues | |
4364 | to stop if a function that has debugging information is called within | |
4365 | the line. In other words, @code{step} @emph{steps inside} any functions | |
4366 | called within the line. | |
c906108c | 4367 | |
d4f3574e SS |
4368 | Also, the @code{step} command only enters a function if there is line |
4369 | number information for the function. Otherwise it acts like the | |
5d161b24 | 4370 | @code{next} command. This avoids problems when using @code{cc -gl} |
c906108c | 4371 | on MIPS machines. Previously, @code{step} entered subroutines if there |
5d161b24 | 4372 | was any debugging information about the routine. |
c906108c SS |
4373 | |
4374 | @item step @var{count} | |
4375 | Continue running as in @code{step}, but do so @var{count} times. If a | |
7a292a7a SS |
4376 | breakpoint is reached, or a signal not related to stepping occurs before |
4377 | @var{count} steps, stepping stops right away. | |
c906108c SS |
4378 | |
4379 | @kindex next | |
41afff9a | 4380 | @kindex n @r{(@code{next})} |
c906108c SS |
4381 | @item next @r{[}@var{count}@r{]} |
4382 | Continue to the next source line in the current (innermost) stack frame. | |
7a292a7a SS |
4383 | This is similar to @code{step}, but function calls that appear within |
4384 | the line of code are executed without stopping. Execution stops when | |
4385 | control reaches a different line of code at the original stack level | |
4386 | that was executing when you gave the @code{next} command. This command | |
4387 | is abbreviated @code{n}. | |
c906108c SS |
4388 | |
4389 | An argument @var{count} is a repeat count, as for @code{step}. | |
4390 | ||
4391 | ||
4392 | @c FIX ME!! Do we delete this, or is there a way it fits in with | |
4393 | @c the following paragraph? --- Vctoria | |
4394 | @c | |
4395 | @c @code{next} within a function that lacks debugging information acts like | |
4396 | @c @code{step}, but any function calls appearing within the code of the | |
4397 | @c function are executed without stopping. | |
4398 | ||
d4f3574e SS |
4399 | The @code{next} command only stops at the first instruction of a |
4400 | source line. This prevents multiple stops that could otherwise occur in | |
4a92d011 | 4401 | @code{switch} statements, @code{for} loops, etc. |
c906108c | 4402 | |
b90a5f51 CF |
4403 | @kindex set step-mode |
4404 | @item set step-mode | |
4405 | @cindex functions without line info, and stepping | |
4406 | @cindex stepping into functions with no line info | |
4407 | @itemx set step-mode on | |
4a92d011 | 4408 | The @code{set step-mode on} command causes the @code{step} command to |
b90a5f51 CF |
4409 | stop at the first instruction of a function which contains no debug line |
4410 | information rather than stepping over it. | |
4411 | ||
4a92d011 EZ |
4412 | This is useful in cases where you may be interested in inspecting the |
4413 | machine instructions of a function which has no symbolic info and do not | |
4414 | want @value{GDBN} to automatically skip over this function. | |
b90a5f51 CF |
4415 | |
4416 | @item set step-mode off | |
4a92d011 | 4417 | Causes the @code{step} command to step over any functions which contains no |
b90a5f51 CF |
4418 | debug information. This is the default. |
4419 | ||
9c16f35a EZ |
4420 | @item show step-mode |
4421 | Show whether @value{GDBN} will stop in or step over functions without | |
4422 | source line debug information. | |
4423 | ||
c906108c | 4424 | @kindex finish |
8dfa32fc | 4425 | @kindex fin @r{(@code{finish})} |
c906108c SS |
4426 | @item finish |
4427 | Continue running until just after function in the selected stack frame | |
8dfa32fc JB |
4428 | returns. Print the returned value (if any). This command can be |
4429 | abbreviated as @code{fin}. | |
c906108c SS |
4430 | |
4431 | Contrast this with the @code{return} command (@pxref{Returning, | |
79a6e687 | 4432 | ,Returning from a Function}). |
c906108c SS |
4433 | |
4434 | @kindex until | |
41afff9a | 4435 | @kindex u @r{(@code{until})} |
09d4efe1 | 4436 | @cindex run until specified location |
c906108c SS |
4437 | @item until |
4438 | @itemx u | |
4439 | Continue running until a source line past the current line, in the | |
4440 | current stack frame, is reached. This command is used to avoid single | |
4441 | stepping through a loop more than once. It is like the @code{next} | |
4442 | command, except that when @code{until} encounters a jump, it | |
4443 | automatically continues execution until the program counter is greater | |
4444 | than the address of the jump. | |
4445 | ||
4446 | This means that when you reach the end of a loop after single stepping | |
4447 | though it, @code{until} makes your program continue execution until it | |
4448 | exits the loop. In contrast, a @code{next} command at the end of a loop | |
4449 | simply steps back to the beginning of the loop, which forces you to step | |
4450 | through the next iteration. | |
4451 | ||
4452 | @code{until} always stops your program if it attempts to exit the current | |
4453 | stack frame. | |
4454 | ||
4455 | @code{until} may produce somewhat counterintuitive results if the order | |
4456 | of machine code does not match the order of the source lines. For | |
4457 | example, in the following excerpt from a debugging session, the @code{f} | |
4458 | (@code{frame}) command shows that execution is stopped at line | |
4459 | @code{206}; yet when we use @code{until}, we get to line @code{195}: | |
4460 | ||
474c8240 | 4461 | @smallexample |
c906108c SS |
4462 | (@value{GDBP}) f |
4463 | #0 main (argc=4, argv=0xf7fffae8) at m4.c:206 | |
4464 | 206 expand_input(); | |
4465 | (@value{GDBP}) until | |
4466 | 195 for ( ; argc > 0; NEXTARG) @{ | |
474c8240 | 4467 | @end smallexample |
c906108c SS |
4468 | |
4469 | This happened because, for execution efficiency, the compiler had | |
4470 | generated code for the loop closure test at the end, rather than the | |
4471 | start, of the loop---even though the test in a C @code{for}-loop is | |
4472 | written before the body of the loop. The @code{until} command appeared | |
4473 | to step back to the beginning of the loop when it advanced to this | |
4474 | expression; however, it has not really gone to an earlier | |
4475 | statement---not in terms of the actual machine code. | |
4476 | ||
4477 | @code{until} with no argument works by means of single | |
4478 | instruction stepping, and hence is slower than @code{until} with an | |
4479 | argument. | |
4480 | ||
4481 | @item until @var{location} | |
4482 | @itemx u @var{location} | |
4483 | Continue running your program until either the specified location is | |
4484 | reached, or the current stack frame returns. @var{location} is any of | |
2a25a5ba EZ |
4485 | the forms described in @ref{Specify Location}. |
4486 | This form of the command uses temporary breakpoints, and | |
c60eb6f1 EZ |
4487 | hence is quicker than @code{until} without an argument. The specified |
4488 | location is actually reached only if it is in the current frame. This | |
4489 | implies that @code{until} can be used to skip over recursive function | |
4490 | invocations. For instance in the code below, if the current location is | |
4491 | line @code{96}, issuing @code{until 99} will execute the program up to | |
db2e3e2e | 4492 | line @code{99} in the same invocation of factorial, i.e., after the inner |
c60eb6f1 EZ |
4493 | invocations have returned. |
4494 | ||
4495 | @smallexample | |
4496 | 94 int factorial (int value) | |
4497 | 95 @{ | |
4498 | 96 if (value > 1) @{ | |
4499 | 97 value *= factorial (value - 1); | |
4500 | 98 @} | |
4501 | 99 return (value); | |
4502 | 100 @} | |
4503 | @end smallexample | |
4504 | ||
4505 | ||
4506 | @kindex advance @var{location} | |
4507 | @itemx advance @var{location} | |
09d4efe1 | 4508 | Continue running the program up to the given @var{location}. An argument is |
2a25a5ba EZ |
4509 | required, which should be of one of the forms described in |
4510 | @ref{Specify Location}. | |
4511 | Execution will also stop upon exit from the current stack | |
c60eb6f1 EZ |
4512 | frame. This command is similar to @code{until}, but @code{advance} will |
4513 | not skip over recursive function calls, and the target location doesn't | |
4514 | have to be in the same frame as the current one. | |
4515 | ||
c906108c SS |
4516 | |
4517 | @kindex stepi | |
41afff9a | 4518 | @kindex si @r{(@code{stepi})} |
c906108c | 4519 | @item stepi |
96a2c332 | 4520 | @itemx stepi @var{arg} |
c906108c SS |
4521 | @itemx si |
4522 | Execute one machine instruction, then stop and return to the debugger. | |
4523 | ||
4524 | It is often useful to do @samp{display/i $pc} when stepping by machine | |
4525 | instructions. This makes @value{GDBN} automatically display the next | |
4526 | instruction to be executed, each time your program stops. @xref{Auto | |
79a6e687 | 4527 | Display,, Automatic Display}. |
c906108c SS |
4528 | |
4529 | An argument is a repeat count, as in @code{step}. | |
4530 | ||
4531 | @need 750 | |
4532 | @kindex nexti | |
41afff9a | 4533 | @kindex ni @r{(@code{nexti})} |
c906108c | 4534 | @item nexti |
96a2c332 | 4535 | @itemx nexti @var{arg} |
c906108c SS |
4536 | @itemx ni |
4537 | Execute one machine instruction, but if it is a function call, | |
4538 | proceed until the function returns. | |
4539 | ||
4540 | An argument is a repeat count, as in @code{next}. | |
4541 | @end table | |
4542 | ||
6d2ebf8b | 4543 | @node Signals |
c906108c SS |
4544 | @section Signals |
4545 | @cindex signals | |
4546 | ||
4547 | A signal is an asynchronous event that can happen in a program. The | |
4548 | operating system defines the possible kinds of signals, and gives each | |
4549 | kind a name and a number. For example, in Unix @code{SIGINT} is the | |
c8aa23ab | 4550 | signal a program gets when you type an interrupt character (often @kbd{Ctrl-c}); |
c906108c SS |
4551 | @code{SIGSEGV} is the signal a program gets from referencing a place in |
4552 | memory far away from all the areas in use; @code{SIGALRM} occurs when | |
4553 | the alarm clock timer goes off (which happens only if your program has | |
4554 | requested an alarm). | |
4555 | ||
4556 | @cindex fatal signals | |
4557 | Some signals, including @code{SIGALRM}, are a normal part of the | |
4558 | functioning of your program. Others, such as @code{SIGSEGV}, indicate | |
d4f3574e | 4559 | errors; these signals are @dfn{fatal} (they kill your program immediately) if the |
c906108c SS |
4560 | program has not specified in advance some other way to handle the signal. |
4561 | @code{SIGINT} does not indicate an error in your program, but it is normally | |
4562 | fatal so it can carry out the purpose of the interrupt: to kill the program. | |
4563 | ||
4564 | @value{GDBN} has the ability to detect any occurrence of a signal in your | |
4565 | program. You can tell @value{GDBN} in advance what to do for each kind of | |
4566 | signal. | |
4567 | ||
4568 | @cindex handling signals | |
24f93129 EZ |
4569 | Normally, @value{GDBN} is set up to let the non-erroneous signals like |
4570 | @code{SIGALRM} be silently passed to your program | |
4571 | (so as not to interfere with their role in the program's functioning) | |
c906108c SS |
4572 | but to stop your program immediately whenever an error signal happens. |
4573 | You can change these settings with the @code{handle} command. | |
4574 | ||
4575 | @table @code | |
4576 | @kindex info signals | |
09d4efe1 | 4577 | @kindex info handle |
c906108c | 4578 | @item info signals |
96a2c332 | 4579 | @itemx info handle |
c906108c SS |
4580 | Print a table of all the kinds of signals and how @value{GDBN} has been told to |
4581 | handle each one. You can use this to see the signal numbers of all | |
4582 | the defined types of signals. | |
4583 | ||
45ac1734 EZ |
4584 | @item info signals @var{sig} |
4585 | Similar, but print information only about the specified signal number. | |
4586 | ||
d4f3574e | 4587 | @code{info handle} is an alias for @code{info signals}. |
c906108c SS |
4588 | |
4589 | @kindex handle | |
45ac1734 | 4590 | @item handle @var{signal} @r{[}@var{keywords}@dots{}@r{]} |
5ece1a18 EZ |
4591 | Change the way @value{GDBN} handles signal @var{signal}. @var{signal} |
4592 | can be the number of a signal or its name (with or without the | |
24f93129 | 4593 | @samp{SIG} at the beginning); a list of signal numbers of the form |
5ece1a18 | 4594 | @samp{@var{low}-@var{high}}; or the word @samp{all}, meaning all the |
45ac1734 EZ |
4595 | known signals. Optional arguments @var{keywords}, described below, |
4596 | say what change to make. | |
c906108c SS |
4597 | @end table |
4598 | ||
4599 | @c @group | |
4600 | The keywords allowed by the @code{handle} command can be abbreviated. | |
4601 | Their full names are: | |
4602 | ||
4603 | @table @code | |
4604 | @item nostop | |
4605 | @value{GDBN} should not stop your program when this signal happens. It may | |
4606 | still print a message telling you that the signal has come in. | |
4607 | ||
4608 | @item stop | |
4609 | @value{GDBN} should stop your program when this signal happens. This implies | |
4610 | the @code{print} keyword as well. | |
4611 | ||
4612 | @item print | |
4613 | @value{GDBN} should print a message when this signal happens. | |
4614 | ||
4615 | @item noprint | |
4616 | @value{GDBN} should not mention the occurrence of the signal at all. This | |
4617 | implies the @code{nostop} keyword as well. | |
4618 | ||
4619 | @item pass | |
5ece1a18 | 4620 | @itemx noignore |
c906108c SS |
4621 | @value{GDBN} should allow your program to see this signal; your program |
4622 | can handle the signal, or else it may terminate if the signal is fatal | |
5ece1a18 | 4623 | and not handled. @code{pass} and @code{noignore} are synonyms. |
c906108c SS |
4624 | |
4625 | @item nopass | |
5ece1a18 | 4626 | @itemx ignore |
c906108c | 4627 | @value{GDBN} should not allow your program to see this signal. |
5ece1a18 | 4628 | @code{nopass} and @code{ignore} are synonyms. |
c906108c SS |
4629 | @end table |
4630 | @c @end group | |
4631 | ||
d4f3574e SS |
4632 | When a signal stops your program, the signal is not visible to the |
4633 | program until you | |
c906108c SS |
4634 | continue. Your program sees the signal then, if @code{pass} is in |
4635 | effect for the signal in question @emph{at that time}. In other words, | |
4636 | after @value{GDBN} reports a signal, you can use the @code{handle} | |
4637 | command with @code{pass} or @code{nopass} to control whether your | |
4638 | program sees that signal when you continue. | |
4639 | ||
24f93129 EZ |
4640 | The default is set to @code{nostop}, @code{noprint}, @code{pass} for |
4641 | non-erroneous signals such as @code{SIGALRM}, @code{SIGWINCH} and | |
4642 | @code{SIGCHLD}, and to @code{stop}, @code{print}, @code{pass} for the | |
4643 | erroneous signals. | |
4644 | ||
c906108c SS |
4645 | You can also use the @code{signal} command to prevent your program from |
4646 | seeing a signal, or cause it to see a signal it normally would not see, | |
4647 | or to give it any signal at any time. For example, if your program stopped | |
4648 | due to some sort of memory reference error, you might store correct | |
4649 | values into the erroneous variables and continue, hoping to see more | |
4650 | execution; but your program would probably terminate immediately as | |
4651 | a result of the fatal signal once it saw the signal. To prevent this, | |
4652 | you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your | |
79a6e687 | 4653 | Program a Signal}. |
c906108c | 4654 | |
4aa995e1 PA |
4655 | @cindex extra signal information |
4656 | @anchor{extra signal information} | |
4657 | ||
4658 | On some targets, @value{GDBN} can inspect extra signal information | |
4659 | associated with the intercepted signal, before it is actually | |
4660 | delivered to the program being debugged. This information is exported | |
4661 | by the convenience variable @code{$_siginfo}, and consists of data | |
4662 | that is passed by the kernel to the signal handler at the time of the | |
4663 | receipt of a signal. The data type of the information itself is | |
4664 | target dependent. You can see the data type using the @code{ptype | |
4665 | $_siginfo} command. On Unix systems, it typically corresponds to the | |
4666 | standard @code{siginfo_t} type, as defined in the @file{signal.h} | |
4667 | system header. | |
4668 | ||
4669 | Here's an example, on a @sc{gnu}/Linux system, printing the stray | |
4670 | referenced address that raised a segmentation fault. | |
4671 | ||
4672 | @smallexample | |
4673 | @group | |
4674 | (@value{GDBP}) continue | |
4675 | Program received signal SIGSEGV, Segmentation fault. | |
4676 | 0x0000000000400766 in main () | |
4677 | 69 *(int *)p = 0; | |
4678 | (@value{GDBP}) ptype $_siginfo | |
4679 | type = struct @{ | |
4680 | int si_signo; | |
4681 | int si_errno; | |
4682 | int si_code; | |
4683 | union @{ | |
4684 | int _pad[28]; | |
4685 | struct @{...@} _kill; | |
4686 | struct @{...@} _timer; | |
4687 | struct @{...@} _rt; | |
4688 | struct @{...@} _sigchld; | |
4689 | struct @{...@} _sigfault; | |
4690 | struct @{...@} _sigpoll; | |
4691 | @} _sifields; | |
4692 | @} | |
4693 | (@value{GDBP}) ptype $_siginfo._sifields._sigfault | |
4694 | type = struct @{ | |
4695 | void *si_addr; | |
4696 | @} | |
4697 | (@value{GDBP}) p $_siginfo._sifields._sigfault.si_addr | |
4698 | $1 = (void *) 0x7ffff7ff7000 | |
4699 | @end group | |
4700 | @end smallexample | |
4701 | ||
4702 | Depending on target support, @code{$_siginfo} may also be writable. | |
4703 | ||
6d2ebf8b | 4704 | @node Thread Stops |
79a6e687 | 4705 | @section Stopping and Starting Multi-thread Programs |
c906108c | 4706 | |
0606b73b SL |
4707 | @cindex stopped threads |
4708 | @cindex threads, stopped | |
4709 | ||
4710 | @cindex continuing threads | |
4711 | @cindex threads, continuing | |
4712 | ||
4713 | @value{GDBN} supports debugging programs with multiple threads | |
4714 | (@pxref{Threads,, Debugging Programs with Multiple Threads}). There | |
4715 | are two modes of controlling execution of your program within the | |
4716 | debugger. In the default mode, referred to as @dfn{all-stop mode}, | |
4717 | when any thread in your program stops (for example, at a breakpoint | |
4718 | or while being stepped), all other threads in the program are also stopped by | |
4719 | @value{GDBN}. On some targets, @value{GDBN} also supports | |
4720 | @dfn{non-stop mode}, in which other threads can continue to run freely while | |
4721 | you examine the stopped thread in the debugger. | |
4722 | ||
4723 | @menu | |
4724 | * All-Stop Mode:: All threads stop when GDB takes control | |
4725 | * Non-Stop Mode:: Other threads continue to execute | |
4726 | * Background Execution:: Running your program asynchronously | |
4727 | * Thread-Specific Breakpoints:: Controlling breakpoints | |
4728 | * Interrupted System Calls:: GDB may interfere with system calls | |
4729 | @end menu | |
4730 | ||
4731 | @node All-Stop Mode | |
4732 | @subsection All-Stop Mode | |
4733 | ||
4734 | @cindex all-stop mode | |
4735 | ||
4736 | In all-stop mode, whenever your program stops under @value{GDBN} for any reason, | |
4737 | @emph{all} threads of execution stop, not just the current thread. This | |
4738 | allows you to examine the overall state of the program, including | |
4739 | switching between threads, without worrying that things may change | |
4740 | underfoot. | |
4741 | ||
4742 | Conversely, whenever you restart the program, @emph{all} threads start | |
4743 | executing. @emph{This is true even when single-stepping} with commands | |
4744 | like @code{step} or @code{next}. | |
4745 | ||
4746 | In particular, @value{GDBN} cannot single-step all threads in lockstep. | |
4747 | Since thread scheduling is up to your debugging target's operating | |
4748 | system (not controlled by @value{GDBN}), other threads may | |
4749 | execute more than one statement while the current thread completes a | |
4750 | single step. Moreover, in general other threads stop in the middle of a | |
4751 | statement, rather than at a clean statement boundary, when the program | |
4752 | stops. | |
4753 | ||
4754 | You might even find your program stopped in another thread after | |
4755 | continuing or even single-stepping. This happens whenever some other | |
4756 | thread runs into a breakpoint, a signal, or an exception before the | |
4757 | first thread completes whatever you requested. | |
4758 | ||
4759 | @cindex automatic thread selection | |
4760 | @cindex switching threads automatically | |
4761 | @cindex threads, automatic switching | |
4762 | Whenever @value{GDBN} stops your program, due to a breakpoint or a | |
4763 | signal, it automatically selects the thread where that breakpoint or | |
4764 | signal happened. @value{GDBN} alerts you to the context switch with a | |
4765 | message such as @samp{[Switching to Thread @var{n}]} to identify the | |
4766 | thread. | |
4767 | ||
4768 | On some OSes, you can modify @value{GDBN}'s default behavior by | |
4769 | locking the OS scheduler to allow only a single thread to run. | |
4770 | ||
4771 | @table @code | |
4772 | @item set scheduler-locking @var{mode} | |
4773 | @cindex scheduler locking mode | |
4774 | @cindex lock scheduler | |
4775 | Set the scheduler locking mode. If it is @code{off}, then there is no | |
4776 | locking and any thread may run at any time. If @code{on}, then only the | |
4777 | current thread may run when the inferior is resumed. The @code{step} | |
4778 | mode optimizes for single-stepping; it prevents other threads | |
4779 | from preempting the current thread while you are stepping, so that | |
4780 | the focus of debugging does not change unexpectedly. | |
4781 | Other threads only rarely (or never) get a chance to run | |
4782 | when you step. They are more likely to run when you @samp{next} over a | |
4783 | function call, and they are completely free to run when you use commands | |
4784 | like @samp{continue}, @samp{until}, or @samp{finish}. However, unless another | |
4785 | thread hits a breakpoint during its timeslice, @value{GDBN} does not change | |
4786 | the current thread away from the thread that you are debugging. | |
4787 | ||
4788 | @item show scheduler-locking | |
4789 | Display the current scheduler locking mode. | |
4790 | @end table | |
4791 | ||
d4db2f36 PA |
4792 | @cindex resume threads of multiple processes simultaneously |
4793 | By default, when you issue one of the execution commands such as | |
4794 | @code{continue}, @code{next} or @code{step}, @value{GDBN} allows only | |
4795 | threads of the current inferior to run. For example, if @value{GDBN} | |
4796 | is attached to two inferiors, each with two threads, the | |
4797 | @code{continue} command resumes only the two threads of the current | |
4798 | inferior. This is useful, for example, when you debug a program that | |
4799 | forks and you want to hold the parent stopped (so that, for instance, | |
4800 | it doesn't run to exit), while you debug the child. In other | |
4801 | situations, you may not be interested in inspecting the current state | |
4802 | of any of the processes @value{GDBN} is attached to, and you may want | |
4803 | to resume them all until some breakpoint is hit. In the latter case, | |
4804 | you can instruct @value{GDBN} to allow all threads of all the | |
4805 | inferiors to run with the @w{@code{set schedule-multiple}} command. | |
4806 | ||
4807 | @table @code | |
4808 | @kindex set schedule-multiple | |
4809 | @item set schedule-multiple | |
4810 | Set the mode for allowing threads of multiple processes to be resumed | |
4811 | when an execution command is issued. When @code{on}, all threads of | |
4812 | all processes are allowed to run. When @code{off}, only the threads | |
4813 | of the current process are resumed. The default is @code{off}. The | |
4814 | @code{scheduler-locking} mode takes precedence when set to @code{on}, | |
4815 | or while you are stepping and set to @code{step}. | |
4816 | ||
4817 | @item show schedule-multiple | |
4818 | Display the current mode for resuming the execution of threads of | |
4819 | multiple processes. | |
4820 | @end table | |
4821 | ||
0606b73b SL |
4822 | @node Non-Stop Mode |
4823 | @subsection Non-Stop Mode | |
4824 | ||
4825 | @cindex non-stop mode | |
4826 | ||
4827 | @c This section is really only a place-holder, and needs to be expanded | |
4828 | @c with more details. | |
4829 | ||
4830 | For some multi-threaded targets, @value{GDBN} supports an optional | |
4831 | mode of operation in which you can examine stopped program threads in | |
4832 | the debugger while other threads continue to execute freely. This | |
4833 | minimizes intrusion when debugging live systems, such as programs | |
4834 | where some threads have real-time constraints or must continue to | |
4835 | respond to external events. This is referred to as @dfn{non-stop} mode. | |
4836 | ||
4837 | In non-stop mode, when a thread stops to report a debugging event, | |
4838 | @emph{only} that thread is stopped; @value{GDBN} does not stop other | |
4839 | threads as well, in contrast to the all-stop mode behavior. Additionally, | |
4840 | execution commands such as @code{continue} and @code{step} apply by default | |
4841 | only to the current thread in non-stop mode, rather than all threads as | |
4842 | in all-stop mode. This allows you to control threads explicitly in | |
4843 | ways that are not possible in all-stop mode --- for example, stepping | |
4844 | one thread while allowing others to run freely, stepping | |
4845 | one thread while holding all others stopped, or stepping several threads | |
4846 | independently and simultaneously. | |
4847 | ||
4848 | To enter non-stop mode, use this sequence of commands before you run | |
4849 | or attach to your program: | |
4850 | ||
0606b73b SL |
4851 | @smallexample |
4852 | # Enable the async interface. | |
c6ebd6cf | 4853 | set target-async 1 |
0606b73b | 4854 | |
0606b73b SL |
4855 | # If using the CLI, pagination breaks non-stop. |
4856 | set pagination off | |
4857 | ||
4858 | # Finally, turn it on! | |
4859 | set non-stop on | |
4860 | @end smallexample | |
4861 | ||
4862 | You can use these commands to manipulate the non-stop mode setting: | |
4863 | ||
4864 | @table @code | |
4865 | @kindex set non-stop | |
4866 | @item set non-stop on | |
4867 | Enable selection of non-stop mode. | |
4868 | @item set non-stop off | |
4869 | Disable selection of non-stop mode. | |
4870 | @kindex show non-stop | |
4871 | @item show non-stop | |
4872 | Show the current non-stop enablement setting. | |
4873 | @end table | |
4874 | ||
4875 | Note these commands only reflect whether non-stop mode is enabled, | |
4876 | not whether the currently-executing program is being run in non-stop mode. | |
4877 | In particular, the @code{set non-stop} preference is only consulted when | |
4878 | @value{GDBN} starts or connects to the target program, and it is generally | |
4879 | not possible to switch modes once debugging has started. Furthermore, | |
4880 | since not all targets support non-stop mode, even when you have enabled | |
4881 | non-stop mode, @value{GDBN} may still fall back to all-stop operation by | |
4882 | default. | |
4883 | ||
4884 | In non-stop mode, all execution commands apply only to the current thread | |
4885 | by default. That is, @code{continue} only continues one thread. | |
4886 | To continue all threads, issue @code{continue -a} or @code{c -a}. | |
4887 | ||
4888 | You can use @value{GDBN}'s background execution commands | |
4889 | (@pxref{Background Execution}) to run some threads in the background | |
4890 | while you continue to examine or step others from @value{GDBN}. | |
4891 | The MI execution commands (@pxref{GDB/MI Program Execution}) are | |
4892 | always executed asynchronously in non-stop mode. | |
4893 | ||
4894 | Suspending execution is done with the @code{interrupt} command when | |
4895 | running in the background, or @kbd{Ctrl-c} during foreground execution. | |
4896 | In all-stop mode, this stops the whole process; | |
4897 | but in non-stop mode the interrupt applies only to the current thread. | |
4898 | To stop the whole program, use @code{interrupt -a}. | |
4899 | ||
4900 | Other execution commands do not currently support the @code{-a} option. | |
4901 | ||
4902 | In non-stop mode, when a thread stops, @value{GDBN} doesn't automatically make | |
4903 | that thread current, as it does in all-stop mode. This is because the | |
4904 | thread stop notifications are asynchronous with respect to @value{GDBN}'s | |
4905 | command interpreter, and it would be confusing if @value{GDBN} unexpectedly | |
4906 | changed to a different thread just as you entered a command to operate on the | |
4907 | previously current thread. | |
4908 | ||
4909 | @node Background Execution | |
4910 | @subsection Background Execution | |
4911 | ||
4912 | @cindex foreground execution | |
4913 | @cindex background execution | |
4914 | @cindex asynchronous execution | |
4915 | @cindex execution, foreground, background and asynchronous | |
4916 | ||
4917 | @value{GDBN}'s execution commands have two variants: the normal | |
4918 | foreground (synchronous) behavior, and a background | |
4919 | (asynchronous) behavior. In foreground execution, @value{GDBN} waits for | |
4920 | the program to report that some thread has stopped before prompting for | |
4921 | another command. In background execution, @value{GDBN} immediately gives | |
4922 | a command prompt so that you can issue other commands while your program runs. | |
4923 | ||
32fc0df9 PA |
4924 | You need to explicitly enable asynchronous mode before you can use |
4925 | background execution commands. You can use these commands to | |
4926 | manipulate the asynchronous mode setting: | |
4927 | ||
4928 | @table @code | |
4929 | @kindex set target-async | |
4930 | @item set target-async on | |
4931 | Enable asynchronous mode. | |
4932 | @item set target-async off | |
4933 | Disable asynchronous mode. | |
4934 | @kindex show target-async | |
4935 | @item show target-async | |
4936 | Show the current target-async setting. | |
4937 | @end table | |
4938 | ||
4939 | If the target doesn't support async mode, @value{GDBN} issues an error | |
4940 | message if you attempt to use the background execution commands. | |
4941 | ||
0606b73b SL |
4942 | To specify background execution, add a @code{&} to the command. For example, |
4943 | the background form of the @code{continue} command is @code{continue&}, or | |
4944 | just @code{c&}. The execution commands that accept background execution | |
4945 | are: | |
4946 | ||
4947 | @table @code | |
4948 | @kindex run& | |
4949 | @item run | |
4950 | @xref{Starting, , Starting your Program}. | |
4951 | ||
4952 | @item attach | |
4953 | @kindex attach& | |
4954 | @xref{Attach, , Debugging an Already-running Process}. | |
4955 | ||
4956 | @item step | |
4957 | @kindex step& | |
4958 | @xref{Continuing and Stepping, step}. | |
4959 | ||
4960 | @item stepi | |
4961 | @kindex stepi& | |
4962 | @xref{Continuing and Stepping, stepi}. | |
4963 | ||
4964 | @item next | |
4965 | @kindex next& | |
4966 | @xref{Continuing and Stepping, next}. | |
4967 | ||
7ce58dd2 DE |
4968 | @item nexti |
4969 | @kindex nexti& | |
4970 | @xref{Continuing and Stepping, nexti}. | |
4971 | ||
0606b73b SL |
4972 | @item continue |
4973 | @kindex continue& | |
4974 | @xref{Continuing and Stepping, continue}. | |
4975 | ||
4976 | @item finish | |
4977 | @kindex finish& | |
4978 | @xref{Continuing and Stepping, finish}. | |
4979 | ||
4980 | @item until | |
4981 | @kindex until& | |
4982 | @xref{Continuing and Stepping, until}. | |
4983 | ||
4984 | @end table | |
4985 | ||
4986 | Background execution is especially useful in conjunction with non-stop | |
4987 | mode for debugging programs with multiple threads; see @ref{Non-Stop Mode}. | |
4988 | However, you can also use these commands in the normal all-stop mode with | |
4989 | the restriction that you cannot issue another execution command until the | |
4990 | previous one finishes. Examples of commands that are valid in all-stop | |
4991 | mode while the program is running include @code{help} and @code{info break}. | |
4992 | ||
4993 | You can interrupt your program while it is running in the background by | |
4994 | using the @code{interrupt} command. | |
4995 | ||
4996 | @table @code | |
4997 | @kindex interrupt | |
4998 | @item interrupt | |
4999 | @itemx interrupt -a | |
5000 | ||
5001 | Suspend execution of the running program. In all-stop mode, | |
5002 | @code{interrupt} stops the whole process, but in non-stop mode, it stops | |
5003 | only the current thread. To stop the whole program in non-stop mode, | |
5004 | use @code{interrupt -a}. | |
5005 | @end table | |
5006 | ||
0606b73b SL |
5007 | @node Thread-Specific Breakpoints |
5008 | @subsection Thread-Specific Breakpoints | |
5009 | ||
c906108c | 5010 | When your program has multiple threads (@pxref{Threads,, Debugging |
79a6e687 | 5011 | Programs with Multiple Threads}), you can choose whether to set |
c906108c SS |
5012 | breakpoints on all threads, or on a particular thread. |
5013 | ||
5014 | @table @code | |
5015 | @cindex breakpoints and threads | |
5016 | @cindex thread breakpoints | |
5017 | @kindex break @dots{} thread @var{threadno} | |
5018 | @item break @var{linespec} thread @var{threadno} | |
5019 | @itemx break @var{linespec} thread @var{threadno} if @dots{} | |
5020 | @var{linespec} specifies source lines; there are several ways of | |
2a25a5ba EZ |
5021 | writing them (@pxref{Specify Location}), but the effect is always to |
5022 | specify some source line. | |
c906108c SS |
5023 | |
5024 | Use the qualifier @samp{thread @var{threadno}} with a breakpoint command | |
5025 | to specify that you only want @value{GDBN} to stop the program when a | |
5026 | particular thread reaches this breakpoint. @var{threadno} is one of the | |
5027 | numeric thread identifiers assigned by @value{GDBN}, shown in the first | |
5028 | column of the @samp{info threads} display. | |
5029 | ||
5030 | If you do not specify @samp{thread @var{threadno}} when you set a | |
5031 | breakpoint, the breakpoint applies to @emph{all} threads of your | |
5032 | program. | |
5033 | ||
5034 | You can use the @code{thread} qualifier on conditional breakpoints as | |
5035 | well; in this case, place @samp{thread @var{threadno}} before the | |
5036 | breakpoint condition, like this: | |
5037 | ||
5038 | @smallexample | |
2df3850c | 5039 | (@value{GDBP}) break frik.c:13 thread 28 if bartab > lim |
c906108c SS |
5040 | @end smallexample |
5041 | ||
5042 | @end table | |
5043 | ||
0606b73b SL |
5044 | @node Interrupted System Calls |
5045 | @subsection Interrupted System Calls | |
c906108c | 5046 | |
36d86913 MC |
5047 | @cindex thread breakpoints and system calls |
5048 | @cindex system calls and thread breakpoints | |
5049 | @cindex premature return from system calls | |
0606b73b SL |
5050 | There is an unfortunate side effect when using @value{GDBN} to debug |
5051 | multi-threaded programs. If one thread stops for a | |
36d86913 MC |
5052 | breakpoint, or for some other reason, and another thread is blocked in a |
5053 | system call, then the system call may return prematurely. This is a | |
5054 | consequence of the interaction between multiple threads and the signals | |
5055 | that @value{GDBN} uses to implement breakpoints and other events that | |
5056 | stop execution. | |
5057 | ||
5058 | To handle this problem, your program should check the return value of | |
5059 | each system call and react appropriately. This is good programming | |
5060 | style anyways. | |
5061 | ||
5062 | For example, do not write code like this: | |
5063 | ||
5064 | @smallexample | |
5065 | sleep (10); | |
5066 | @end smallexample | |
5067 | ||
5068 | The call to @code{sleep} will return early if a different thread stops | |
5069 | at a breakpoint or for some other reason. | |
5070 | ||
5071 | Instead, write this: | |
5072 | ||
5073 | @smallexample | |
5074 | int unslept = 10; | |
5075 | while (unslept > 0) | |
5076 | unslept = sleep (unslept); | |
5077 | @end smallexample | |
5078 | ||
5079 | A system call is allowed to return early, so the system is still | |
5080 | conforming to its specification. But @value{GDBN} does cause your | |
5081 | multi-threaded program to behave differently than it would without | |
5082 | @value{GDBN}. | |
5083 | ||
5084 | Also, @value{GDBN} uses internal breakpoints in the thread library to | |
5085 | monitor certain events such as thread creation and thread destruction. | |
5086 | When such an event happens, a system call in another thread may return | |
5087 | prematurely, even though your program does not appear to stop. | |
5088 | ||
c906108c | 5089 | |
bacec72f MS |
5090 | @node Reverse Execution |
5091 | @chapter Running programs backward | |
5092 | @cindex reverse execution | |
5093 | @cindex running programs backward | |
5094 | ||
5095 | When you are debugging a program, it is not unusual to realize that | |
5096 | you have gone too far, and some event of interest has already happened. | |
5097 | If the target environment supports it, @value{GDBN} can allow you to | |
5098 | ``rewind'' the program by running it backward. | |
5099 | ||
5100 | A target environment that supports reverse execution should be able | |
5101 | to ``undo'' the changes in machine state that have taken place as the | |
5102 | program was executing normally. Variables, registers etc.@: should | |
5103 | revert to their previous values. Obviously this requires a great | |
5104 | deal of sophistication on the part of the target environment; not | |
5105 | all target environments can support reverse execution. | |
5106 | ||
5107 | When a program is executed in reverse, the instructions that | |
5108 | have most recently been executed are ``un-executed'', in reverse | |
5109 | order. The program counter runs backward, following the previous | |
5110 | thread of execution in reverse. As each instruction is ``un-executed'', | |
5111 | the values of memory and/or registers that were changed by that | |
5112 | instruction are reverted to their previous states. After executing | |
5113 | a piece of source code in reverse, all side effects of that code | |
5114 | should be ``undone'', and all variables should be returned to their | |
5115 | prior values@footnote{ | |
5116 | Note that some side effects are easier to undo than others. For instance, | |
5117 | memory and registers are relatively easy, but device I/O is hard. Some | |
5118 | targets may be able undo things like device I/O, and some may not. | |
5119 | ||
5120 | The contract between @value{GDBN} and the reverse executing target | |
5121 | requires only that the target do something reasonable when | |
5122 | @value{GDBN} tells it to execute backwards, and then report the | |
5123 | results back to @value{GDBN}. Whatever the target reports back to | |
5124 | @value{GDBN}, @value{GDBN} will report back to the user. @value{GDBN} | |
5125 | assumes that the memory and registers that the target reports are in a | |
5126 | consistant state, but @value{GDBN} accepts whatever it is given. | |
5127 | }. | |
5128 | ||
5129 | If you are debugging in a target environment that supports | |
5130 | reverse execution, @value{GDBN} provides the following commands. | |
5131 | ||
5132 | @table @code | |
5133 | @kindex reverse-continue | |
5134 | @kindex rc @r{(@code{reverse-continue})} | |
5135 | @item reverse-continue @r{[}@var{ignore-count}@r{]} | |
5136 | @itemx rc @r{[}@var{ignore-count}@r{]} | |
5137 | Beginning at the point where your program last stopped, start executing | |
5138 | in reverse. Reverse execution will stop for breakpoints and synchronous | |
5139 | exceptions (signals), just like normal execution. Behavior of | |
5140 | asynchronous signals depends on the target environment. | |
5141 | ||
5142 | @kindex reverse-step | |
5143 | @kindex rs @r{(@code{step})} | |
5144 | @item reverse-step @r{[}@var{count}@r{]} | |
5145 | Run the program backward until control reaches the start of a | |
5146 | different source line; then stop it, and return control to @value{GDBN}. | |
5147 | ||
5148 | Like the @code{step} command, @code{reverse-step} will only stop | |
5149 | at the beginning of a source line. It ``un-executes'' the previously | |
5150 | executed source line. If the previous source line included calls to | |
5151 | debuggable functions, @code{reverse-step} will step (backward) into | |
5152 | the called function, stopping at the beginning of the @emph{last} | |
5153 | statement in the called function (typically a return statement). | |
5154 | ||
5155 | Also, as with the @code{step} command, if non-debuggable functions are | |
5156 | called, @code{reverse-step} will run thru them backward without stopping. | |
5157 | ||
5158 | @kindex reverse-stepi | |
5159 | @kindex rsi @r{(@code{reverse-stepi})} | |
5160 | @item reverse-stepi @r{[}@var{count}@r{]} | |
5161 | Reverse-execute one machine instruction. Note that the instruction | |
5162 | to be reverse-executed is @emph{not} the one pointed to by the program | |
5163 | counter, but the instruction executed prior to that one. For instance, | |
5164 | if the last instruction was a jump, @code{reverse-stepi} will take you | |
5165 | back from the destination of the jump to the jump instruction itself. | |
5166 | ||
5167 | @kindex reverse-next | |
5168 | @kindex rn @r{(@code{reverse-next})} | |
5169 | @item reverse-next @r{[}@var{count}@r{]} | |
5170 | Run backward to the beginning of the previous line executed in | |
5171 | the current (innermost) stack frame. If the line contains function | |
5172 | calls, they will be ``un-executed'' without stopping. Starting from | |
5173 | the first line of a function, @code{reverse-next} will take you back | |
5174 | to the caller of that function, @emph{before} the function was called, | |
5175 | just as the normal @code{next} command would take you from the last | |
5176 | line of a function back to its return to its caller | |
5177 | @footnote{Unles the code is too heavily optimized.}. | |
5178 | ||
5179 | @kindex reverse-nexti | |
5180 | @kindex rni @r{(@code{reverse-nexti})} | |
5181 | @item reverse-nexti @r{[}@var{count}@r{]} | |
5182 | Like @code{nexti}, @code{reverse-nexti} executes a single instruction | |
5183 | in reverse, except that called functions are ``un-executed'' atomically. | |
5184 | That is, if the previously executed instruction was a return from | |
5185 | another instruction, @code{reverse-nexti} will continue to execute | |
5186 | in reverse until the call to that function (from the current stack | |
5187 | frame) is reached. | |
5188 | ||
5189 | @kindex reverse-finish | |
5190 | @item reverse-finish | |
5191 | Just as the @code{finish} command takes you to the point where the | |
5192 | current function returns, @code{reverse-finish} takes you to the point | |
5193 | where it was called. Instead of ending up at the end of the current | |
5194 | function invocation, you end up at the beginning. | |
5195 | ||
5196 | @kindex set exec-direction | |
5197 | @item set exec-direction | |
5198 | Set the direction of target execution. | |
5199 | @itemx set exec-direction reverse | |
5200 | @cindex execute forward or backward in time | |
5201 | @value{GDBN} will perform all execution commands in reverse, until the | |
5202 | exec-direction mode is changed to ``forward''. Affected commands include | |
5203 | @code{step, stepi, next, nexti, continue, and finish}. The @code{return} | |
5204 | command cannot be used in reverse mode. | |
5205 | @item set exec-direction forward | |
5206 | @value{GDBN} will perform all execution commands in the normal fashion. | |
5207 | This is the default. | |
5208 | @end table | |
5209 | ||
c906108c | 5210 | |
a2311334 EZ |
5211 | @node Process Record and Replay |
5212 | @chapter Recording Inferior's Execution and Replaying It | |
53cc454a HZ |
5213 | @cindex process record and replay |
5214 | @cindex recording inferior's execution and replaying it | |
5215 | ||
8e05493c EZ |
5216 | On some platforms, @value{GDBN} provides a special @dfn{process record |
5217 | and replay} target that can record a log of the process execution, and | |
5218 | replay it later with both forward and reverse execution commands. | |
a2311334 EZ |
5219 | |
5220 | @cindex replay mode | |
5221 | When this target is in use, if the execution log includes the record | |
5222 | for the next instruction, @value{GDBN} will debug in @dfn{replay | |
5223 | mode}. In the replay mode, the inferior does not really execute code | |
5224 | instructions. Instead, all the events that normally happen during | |
5225 | code execution are taken from the execution log. While code is not | |
5226 | really executed in replay mode, the values of registers (including the | |
5227 | program counter register) and the memory of the inferior are still | |
8e05493c EZ |
5228 | changed as they normally would. Their contents are taken from the |
5229 | execution log. | |
a2311334 EZ |
5230 | |
5231 | @cindex record mode | |
5232 | If the record for the next instruction is not in the execution log, | |
5233 | @value{GDBN} will debug in @dfn{record mode}. In this mode, the | |
5234 | inferior executes normally, and @value{GDBN} records the execution log | |
5235 | for future replay. | |
5236 | ||
8e05493c EZ |
5237 | The process record and replay target supports reverse execution |
5238 | (@pxref{Reverse Execution}), even if the platform on which the | |
5239 | inferior runs does not. However, the reverse execution is limited in | |
5240 | this case by the range of the instructions recorded in the execution | |
5241 | log. In other words, reverse execution on platforms that don't | |
5242 | support it directly can only be done in the replay mode. | |
5243 | ||
5244 | When debugging in the reverse direction, @value{GDBN} will work in | |
5245 | replay mode as long as the execution log includes the record for the | |
5246 | previous instruction; otherwise, it will work in record mode, if the | |
5247 | platform supports reverse execution, or stop if not. | |
5248 | ||
a2311334 EZ |
5249 | For architecture environments that support process record and replay, |
5250 | @value{GDBN} provides the following commands: | |
53cc454a HZ |
5251 | |
5252 | @table @code | |
5253 | @kindex target record | |
5254 | @kindex record | |
5255 | @kindex rec | |
5256 | @item target record | |
a2311334 EZ |
5257 | This command starts the process record and replay target. The process |
5258 | record and replay target can only debug a process that is already | |
5259 | running. Therefore, you need first to start the process with the | |
5260 | @kbd{run} or @kbd{start} commands, and then start the recording with | |
5261 | the @kbd{target record} command. | |
5262 | ||
5263 | Both @code{record} and @code{rec} are aliases of @code{target record}. | |
5264 | ||
5265 | @cindex displaced stepping, and process record and replay | |
5266 | Displaced stepping (@pxref{Maintenance Commands,, displaced stepping}) | |
5267 | will be automatically disabled when process record and replay target | |
5268 | is started. That's because the process record and replay target | |
5269 | doesn't support displaced stepping. | |
5270 | ||
5271 | @cindex non-stop mode, and process record and replay | |
5272 | @cindex asynchronous execution, and process record and replay | |
5273 | If the inferior is in the non-stop mode (@pxref{Non-Stop Mode}) or in | |
5274 | the asynchronous execution mode (@pxref{Background Execution}), the | |
5275 | process record and replay target cannot be started because it doesn't | |
5276 | support these two modes. | |
53cc454a HZ |
5277 | |
5278 | @kindex record stop | |
5279 | @kindex rec s | |
5280 | @item record stop | |
a2311334 EZ |
5281 | Stop the process record and replay target. When process record and |
5282 | replay target stops, the entire execution log will be deleted and the | |
5283 | inferior will either be terminated, or will remain in its final state. | |
53cc454a | 5284 | |
a2311334 EZ |
5285 | When you stop the process record and replay target in record mode (at |
5286 | the end of the execution log), the inferior will be stopped at the | |
5287 | next instruction that would have been recorded. In other words, if | |
5288 | you record for a while and then stop recording, the inferior process | |
5289 | will be left in the same state as if the recording never happened. | |
53cc454a | 5290 | |
a2311334 EZ |
5291 | On the other hand, if the process record and replay target is stopped |
5292 | while in replay mode (that is, not at the end of the execution log, | |
5293 | but at some earlier point), the inferior process will become ``live'' | |
5294 | at that earlier state, and it will then be possible to continue the | |
5295 | usual ``live'' debugging of the process from that state. | |
53cc454a | 5296 | |
a2311334 EZ |
5297 | When the inferior process exits, or @value{GDBN} detaches from it, |
5298 | process record and replay target will automatically stop itself. | |
53cc454a HZ |
5299 | |
5300 | @kindex set record insn-number-max | |
5301 | @item set record insn-number-max @var{limit} | |
5302 | Set the limit of instructions to be recorded. Default value is 200000. | |
5303 | ||
a2311334 EZ |
5304 | If @var{limit} is a positive number, then @value{GDBN} will start |
5305 | deleting instructions from the log once the number of the record | |
5306 | instructions becomes greater than @var{limit}. For every new recorded | |
5307 | instruction, @value{GDBN} will delete the earliest recorded | |
5308 | instruction to keep the number of recorded instructions at the limit. | |
5309 | (Since deleting recorded instructions loses information, @value{GDBN} | |
5310 | lets you control what happens when the limit is reached, by means of | |
5311 | the @code{stop-at-limit} option, described below.) | |
53cc454a | 5312 | |
a2311334 EZ |
5313 | If @var{limit} is zero, @value{GDBN} will never delete recorded |
5314 | instructions from the execution log. The number of recorded | |
5315 | instructions is unlimited in this case. | |
53cc454a HZ |
5316 | |
5317 | @kindex show record insn-number-max | |
5318 | @item show record insn-number-max | |
a2311334 | 5319 | Show the limit of instructions to be recorded. |
53cc454a HZ |
5320 | |
5321 | @kindex set record stop-at-limit | |
a2311334 EZ |
5322 | @item set record stop-at-limit |
5323 | Control the behavior when the number of recorded instructions reaches | |
5324 | the limit. If ON (the default), @value{GDBN} will stop when the limit | |
5325 | is reached for the first time and ask you whether you want to stop the | |
5326 | inferior or continue running it and recording the execution log. If | |
5327 | you decide to continue recording, each new recorded instruction will | |
5328 | cause the oldest one to be deleted. | |
53cc454a | 5329 | |
a2311334 EZ |
5330 | If this option is OFF, @value{GDBN} will automatically delete the |
5331 | oldest record to make room for each new one, without asking. | |
53cc454a HZ |
5332 | |
5333 | @kindex show record stop-at-limit | |
5334 | @item show record stop-at-limit | |
a2311334 | 5335 | Show the current setting of @code{stop-at-limit}. |
53cc454a HZ |
5336 | |
5337 | @kindex info record insn-number | |
5338 | @item info record insn-number | |
5339 | Show the current number of recorded instructions. | |
5340 | ||
5341 | @kindex record delete | |
5342 | @kindex rec del | |
5343 | @item record delete | |
a2311334 | 5344 | When record target runs in replay mode (``in the past''), delete the |
53cc454a | 5345 | subsequent execution log and begin to record a new execution log starting |
a2311334 | 5346 | from the current address. This means you will abandon the previously |
53cc454a HZ |
5347 | recorded ``future'' and begin recording a new ``future''. |
5348 | @end table | |
5349 | ||
5350 | ||
6d2ebf8b | 5351 | @node Stack |
c906108c SS |
5352 | @chapter Examining the Stack |
5353 | ||
5354 | When your program has stopped, the first thing you need to know is where it | |
5355 | stopped and how it got there. | |
5356 | ||
5357 | @cindex call stack | |
5d161b24 DB |
5358 | Each time your program performs a function call, information about the call |
5359 | is generated. | |
5360 | That information includes the location of the call in your program, | |
5361 | the arguments of the call, | |
c906108c | 5362 | and the local variables of the function being called. |
5d161b24 | 5363 | The information is saved in a block of data called a @dfn{stack frame}. |
c906108c SS |
5364 | The stack frames are allocated in a region of memory called the @dfn{call |
5365 | stack}. | |
5366 | ||
5367 | When your program stops, the @value{GDBN} commands for examining the | |
5368 | stack allow you to see all of this information. | |
5369 | ||
5370 | @cindex selected frame | |
5371 | One of the stack frames is @dfn{selected} by @value{GDBN} and many | |
5372 | @value{GDBN} commands refer implicitly to the selected frame. In | |
5373 | particular, whenever you ask @value{GDBN} for the value of a variable in | |
5374 | your program, the value is found in the selected frame. There are | |
5375 | special @value{GDBN} commands to select whichever frame you are | |
79a6e687 | 5376 | interested in. @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5377 | |
5378 | When your program stops, @value{GDBN} automatically selects the | |
5d161b24 | 5379 | currently executing frame and describes it briefly, similar to the |
79a6e687 | 5380 | @code{frame} command (@pxref{Frame Info, ,Information about a Frame}). |
c906108c SS |
5381 | |
5382 | @menu | |
5383 | * Frames:: Stack frames | |
5384 | * Backtrace:: Backtraces | |
5385 | * Selection:: Selecting a frame | |
5386 | * Frame Info:: Information on a frame | |
c906108c SS |
5387 | |
5388 | @end menu | |
5389 | ||
6d2ebf8b | 5390 | @node Frames |
79a6e687 | 5391 | @section Stack Frames |
c906108c | 5392 | |
d4f3574e | 5393 | @cindex frame, definition |
c906108c SS |
5394 | @cindex stack frame |
5395 | The call stack is divided up into contiguous pieces called @dfn{stack | |
5396 | frames}, or @dfn{frames} for short; each frame is the data associated | |
5397 | with one call to one function. The frame contains the arguments given | |
5398 | to the function, the function's local variables, and the address at | |
5399 | which the function is executing. | |
5400 | ||
5401 | @cindex initial frame | |
5402 | @cindex outermost frame | |
5403 | @cindex innermost frame | |
5404 | When your program is started, the stack has only one frame, that of the | |
5405 | function @code{main}. This is called the @dfn{initial} frame or the | |
5406 | @dfn{outermost} frame. Each time a function is called, a new frame is | |
5407 | made. Each time a function returns, the frame for that function invocation | |
5408 | is eliminated. If a function is recursive, there can be many frames for | |
5409 | the same function. The frame for the function in which execution is | |
5410 | actually occurring is called the @dfn{innermost} frame. This is the most | |
5411 | recently created of all the stack frames that still exist. | |
5412 | ||
5413 | @cindex frame pointer | |
5414 | Inside your program, stack frames are identified by their addresses. A | |
5415 | stack frame consists of many bytes, each of which has its own address; each | |
5416 | kind of computer has a convention for choosing one byte whose | |
5417 | address serves as the address of the frame. Usually this address is kept | |
e09f16f9 EZ |
5418 | in a register called the @dfn{frame pointer register} |
5419 | (@pxref{Registers, $fp}) while execution is going on in that frame. | |
c906108c SS |
5420 | |
5421 | @cindex frame number | |
5422 | @value{GDBN} assigns numbers to all existing stack frames, starting with | |
5423 | zero for the innermost frame, one for the frame that called it, | |
5424 | and so on upward. These numbers do not really exist in your program; | |
5425 | they are assigned by @value{GDBN} to give you a way of designating stack | |
5426 | frames in @value{GDBN} commands. | |
5427 | ||
6d2ebf8b SS |
5428 | @c The -fomit-frame-pointer below perennially causes hbox overflow |
5429 | @c underflow problems. | |
c906108c SS |
5430 | @cindex frameless execution |
5431 | Some compilers provide a way to compile functions so that they operate | |
e22ea452 | 5432 | without stack frames. (For example, the @value{NGCC} option |
474c8240 | 5433 | @smallexample |
6d2ebf8b | 5434 | @samp{-fomit-frame-pointer} |
474c8240 | 5435 | @end smallexample |
6d2ebf8b | 5436 | generates functions without a frame.) |
c906108c SS |
5437 | This is occasionally done with heavily used library functions to save |
5438 | the frame setup time. @value{GDBN} has limited facilities for dealing | |
5439 | with these function invocations. If the innermost function invocation | |
5440 | has no stack frame, @value{GDBN} nevertheless regards it as though | |
5441 | it had a separate frame, which is numbered zero as usual, allowing | |
5442 | correct tracing of the function call chain. However, @value{GDBN} has | |
5443 | no provision for frameless functions elsewhere in the stack. | |
5444 | ||
5445 | @table @code | |
d4f3574e | 5446 | @kindex frame@r{, command} |
41afff9a | 5447 | @cindex current stack frame |
c906108c | 5448 | @item frame @var{args} |
5d161b24 | 5449 | The @code{frame} command allows you to move from one stack frame to another, |
c906108c | 5450 | and to print the stack frame you select. @var{args} may be either the |
5d161b24 DB |
5451 | address of the frame or the stack frame number. Without an argument, |
5452 | @code{frame} prints the current stack frame. | |
c906108c SS |
5453 | |
5454 | @kindex select-frame | |
41afff9a | 5455 | @cindex selecting frame silently |
c906108c SS |
5456 | @item select-frame |
5457 | The @code{select-frame} command allows you to move from one stack frame | |
5458 | to another without printing the frame. This is the silent version of | |
5459 | @code{frame}. | |
5460 | @end table | |
5461 | ||
6d2ebf8b | 5462 | @node Backtrace |
c906108c SS |
5463 | @section Backtraces |
5464 | ||
09d4efe1 EZ |
5465 | @cindex traceback |
5466 | @cindex call stack traces | |
c906108c SS |
5467 | A backtrace is a summary of how your program got where it is. It shows one |
5468 | line per frame, for many frames, starting with the currently executing | |
5469 | frame (frame zero), followed by its caller (frame one), and on up the | |
5470 | stack. | |
5471 | ||
5472 | @table @code | |
5473 | @kindex backtrace | |
41afff9a | 5474 | @kindex bt @r{(@code{backtrace})} |
c906108c SS |
5475 | @item backtrace |
5476 | @itemx bt | |
5477 | Print a backtrace of the entire stack: one line per frame for all | |
5478 | frames in the stack. | |
5479 | ||
5480 | You can stop the backtrace at any time by typing the system interrupt | |
c8aa23ab | 5481 | character, normally @kbd{Ctrl-c}. |
c906108c SS |
5482 | |
5483 | @item backtrace @var{n} | |
5484 | @itemx bt @var{n} | |
5485 | Similar, but print only the innermost @var{n} frames. | |
5486 | ||
5487 | @item backtrace -@var{n} | |
5488 | @itemx bt -@var{n} | |
5489 | Similar, but print only the outermost @var{n} frames. | |
0f061b69 NR |
5490 | |
5491 | @item backtrace full | |
0f061b69 | 5492 | @itemx bt full |
dd74f6ae NR |
5493 | @itemx bt full @var{n} |
5494 | @itemx bt full -@var{n} | |
e7109c7e | 5495 | Print the values of the local variables also. @var{n} specifies the |
286ba84d | 5496 | number of frames to print, as described above. |
c906108c SS |
5497 | @end table |
5498 | ||
5499 | @kindex where | |
5500 | @kindex info stack | |
c906108c SS |
5501 | The names @code{where} and @code{info stack} (abbreviated @code{info s}) |
5502 | are additional aliases for @code{backtrace}. | |
5503 | ||
839c27b7 EZ |
5504 | @cindex multiple threads, backtrace |
5505 | In a multi-threaded program, @value{GDBN} by default shows the | |
5506 | backtrace only for the current thread. To display the backtrace for | |
5507 | several or all of the threads, use the command @code{thread apply} | |
5508 | (@pxref{Threads, thread apply}). For example, if you type @kbd{thread | |
5509 | apply all backtrace}, @value{GDBN} will display the backtrace for all | |
5510 | the threads; this is handy when you debug a core dump of a | |
5511 | multi-threaded program. | |
5512 | ||
c906108c SS |
5513 | Each line in the backtrace shows the frame number and the function name. |
5514 | The program counter value is also shown---unless you use @code{set | |
5515 | print address off}. The backtrace also shows the source file name and | |
5516 | line number, as well as the arguments to the function. The program | |
5517 | counter value is omitted if it is at the beginning of the code for that | |
5518 | line number. | |
5519 | ||
5520 | Here is an example of a backtrace. It was made with the command | |
5521 | @samp{bt 3}, so it shows the innermost three frames. | |
5522 | ||
5523 | @smallexample | |
5524 | @group | |
5d161b24 | 5525 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) |
c906108c | 5526 | at builtin.c:993 |
4f5376b2 | 5527 | #1 0x6e38 in expand_macro (sym=0x2b600, data=...) at macro.c:242 |
c906108c SS |
5528 | #2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08) |
5529 | at macro.c:71 | |
5530 | (More stack frames follow...) | |
5531 | @end group | |
5532 | @end smallexample | |
5533 | ||
5534 | @noindent | |
5535 | The display for frame zero does not begin with a program counter | |
5536 | value, indicating that your program has stopped at the beginning of the | |
5537 | code for line @code{993} of @code{builtin.c}. | |
5538 | ||
4f5376b2 JB |
5539 | @noindent |
5540 | The value of parameter @code{data} in frame 1 has been replaced by | |
5541 | @code{@dots{}}. By default, @value{GDBN} prints the value of a parameter | |
5542 | only if it is a scalar (integer, pointer, enumeration, etc). See command | |
5543 | @kbd{set print frame-arguments} in @ref{Print Settings} for more details | |
5544 | on how to configure the way function parameter values are printed. | |
5545 | ||
18999be5 EZ |
5546 | @cindex value optimized out, in backtrace |
5547 | @cindex function call arguments, optimized out | |
5548 | If your program was compiled with optimizations, some compilers will | |
5549 | optimize away arguments passed to functions if those arguments are | |
5550 | never used after the call. Such optimizations generate code that | |
5551 | passes arguments through registers, but doesn't store those arguments | |
5552 | in the stack frame. @value{GDBN} has no way of displaying such | |
5553 | arguments in stack frames other than the innermost one. Here's what | |
5554 | such a backtrace might look like: | |
5555 | ||
5556 | @smallexample | |
5557 | @group | |
5558 | #0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8) | |
5559 | at builtin.c:993 | |
5560 | #1 0x6e38 in expand_macro (sym=<value optimized out>) at macro.c:242 | |
5561 | #2 0x6840 in expand_token (obs=0x0, t=<value optimized out>, td=0xf7fffb08) | |
5562 | at macro.c:71 | |
5563 | (More stack frames follow...) | |
5564 | @end group | |
5565 | @end smallexample | |
5566 | ||
5567 | @noindent | |
5568 | The values of arguments that were not saved in their stack frames are | |
5569 | shown as @samp{<value optimized out>}. | |
5570 | ||
5571 | If you need to display the values of such optimized-out arguments, | |
5572 | either deduce that from other variables whose values depend on the one | |
5573 | you are interested in, or recompile without optimizations. | |
5574 | ||
a8f24a35 EZ |
5575 | @cindex backtrace beyond @code{main} function |
5576 | @cindex program entry point | |
5577 | @cindex startup code, and backtrace | |
25d29d70 AC |
5578 | Most programs have a standard user entry point---a place where system |
5579 | libraries and startup code transition into user code. For C this is | |
d416eeec EZ |
5580 | @code{main}@footnote{ |
5581 | Note that embedded programs (the so-called ``free-standing'' | |
5582 | environment) are not required to have a @code{main} function as the | |
5583 | entry point. They could even have multiple entry points.}. | |
5584 | When @value{GDBN} finds the entry function in a backtrace | |
25d29d70 AC |
5585 | it will terminate the backtrace, to avoid tracing into highly |
5586 | system-specific (and generally uninteresting) code. | |
5587 | ||
5588 | If you need to examine the startup code, or limit the number of levels | |
5589 | in a backtrace, you can change this behavior: | |
95f90d25 DJ |
5590 | |
5591 | @table @code | |
25d29d70 AC |
5592 | @item set backtrace past-main |
5593 | @itemx set backtrace past-main on | |
4644b6e3 | 5594 | @kindex set backtrace |
25d29d70 AC |
5595 | Backtraces will continue past the user entry point. |
5596 | ||
5597 | @item set backtrace past-main off | |
95f90d25 DJ |
5598 | Backtraces will stop when they encounter the user entry point. This is the |
5599 | default. | |
5600 | ||
25d29d70 | 5601 | @item show backtrace past-main |
4644b6e3 | 5602 | @kindex show backtrace |
25d29d70 AC |
5603 | Display the current user entry point backtrace policy. |
5604 | ||
2315ffec RC |
5605 | @item set backtrace past-entry |
5606 | @itemx set backtrace past-entry on | |
a8f24a35 | 5607 | Backtraces will continue past the internal entry point of an application. |
2315ffec RC |
5608 | This entry point is encoded by the linker when the application is built, |
5609 | and is likely before the user entry point @code{main} (or equivalent) is called. | |
5610 | ||
5611 | @item set backtrace past-entry off | |
d3e8051b | 5612 | Backtraces will stop when they encounter the internal entry point of an |
2315ffec RC |
5613 | application. This is the default. |
5614 | ||
5615 | @item show backtrace past-entry | |
5616 | Display the current internal entry point backtrace policy. | |
5617 | ||
25d29d70 AC |
5618 | @item set backtrace limit @var{n} |
5619 | @itemx set backtrace limit 0 | |
5620 | @cindex backtrace limit | |
5621 | Limit the backtrace to @var{n} levels. A value of zero means | |
5622 | unlimited. | |
95f90d25 | 5623 | |
25d29d70 AC |
5624 | @item show backtrace limit |
5625 | Display the current limit on backtrace levels. | |
95f90d25 DJ |
5626 | @end table |
5627 | ||
6d2ebf8b | 5628 | @node Selection |
79a6e687 | 5629 | @section Selecting a Frame |
c906108c SS |
5630 | |
5631 | Most commands for examining the stack and other data in your program work on | |
5632 | whichever stack frame is selected at the moment. Here are the commands for | |
5633 | selecting a stack frame; all of them finish by printing a brief description | |
5634 | of the stack frame just selected. | |
5635 | ||
5636 | @table @code | |
d4f3574e | 5637 | @kindex frame@r{, selecting} |
41afff9a | 5638 | @kindex f @r{(@code{frame})} |
c906108c SS |
5639 | @item frame @var{n} |
5640 | @itemx f @var{n} | |
5641 | Select frame number @var{n}. Recall that frame zero is the innermost | |
5642 | (currently executing) frame, frame one is the frame that called the | |
5643 | innermost one, and so on. The highest-numbered frame is the one for | |
5644 | @code{main}. | |
5645 | ||
5646 | @item frame @var{addr} | |
5647 | @itemx f @var{addr} | |
5648 | Select the frame at address @var{addr}. This is useful mainly if the | |
5649 | chaining of stack frames has been damaged by a bug, making it | |
5650 | impossible for @value{GDBN} to assign numbers properly to all frames. In | |
5651 | addition, this can be useful when your program has multiple stacks and | |
5652 | switches between them. | |
5653 | ||
c906108c SS |
5654 | On the SPARC architecture, @code{frame} needs two addresses to |
5655 | select an arbitrary frame: a frame pointer and a stack pointer. | |
5656 | ||
5657 | On the MIPS and Alpha architecture, it needs two addresses: a stack | |
5658 | pointer and a program counter. | |
5659 | ||
5660 | On the 29k architecture, it needs three addresses: a register stack | |
5661 | pointer, a program counter, and a memory stack pointer. | |
c906108c SS |
5662 | |
5663 | @kindex up | |
5664 | @item up @var{n} | |
5665 | Move @var{n} frames up the stack. For positive numbers @var{n}, this | |
5666 | advances toward the outermost frame, to higher frame numbers, to frames | |
5667 | that have existed longer. @var{n} defaults to one. | |
5668 | ||
5669 | @kindex down | |
41afff9a | 5670 | @kindex do @r{(@code{down})} |
c906108c SS |
5671 | @item down @var{n} |
5672 | Move @var{n} frames down the stack. For positive numbers @var{n}, this | |
5673 | advances toward the innermost frame, to lower frame numbers, to frames | |
5674 | that were created more recently. @var{n} defaults to one. You may | |
5675 | abbreviate @code{down} as @code{do}. | |
5676 | @end table | |
5677 | ||
5678 | All of these commands end by printing two lines of output describing the | |
5679 | frame. The first line shows the frame number, the function name, the | |
5680 | arguments, and the source file and line number of execution in that | |
5d161b24 | 5681 | frame. The second line shows the text of that source line. |
c906108c SS |
5682 | |
5683 | @need 1000 | |
5684 | For example: | |
5685 | ||
5686 | @smallexample | |
5687 | @group | |
5688 | (@value{GDBP}) up | |
5689 | #1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc) | |
5690 | at env.c:10 | |
5691 | 10 read_input_file (argv[i]); | |
5692 | @end group | |
5693 | @end smallexample | |
5694 | ||
5695 | After such a printout, the @code{list} command with no arguments | |
5696 | prints ten lines centered on the point of execution in the frame. | |
87885426 FN |
5697 | You can also edit the program at the point of execution with your favorite |
5698 | editing program by typing @code{edit}. | |
79a6e687 | 5699 | @xref{List, ,Printing Source Lines}, |
87885426 | 5700 | for details. |
c906108c SS |
5701 | |
5702 | @table @code | |
5703 | @kindex down-silently | |
5704 | @kindex up-silently | |
5705 | @item up-silently @var{n} | |
5706 | @itemx down-silently @var{n} | |
5707 | These two commands are variants of @code{up} and @code{down}, | |
5708 | respectively; they differ in that they do their work silently, without | |
5709 | causing display of the new frame. They are intended primarily for use | |
5710 | in @value{GDBN} command scripts, where the output might be unnecessary and | |
5711 | distracting. | |
5712 | @end table | |
5713 | ||
6d2ebf8b | 5714 | @node Frame Info |
79a6e687 | 5715 | @section Information About a Frame |
c906108c SS |
5716 | |
5717 | There are several other commands to print information about the selected | |
5718 | stack frame. | |
5719 | ||
5720 | @table @code | |
5721 | @item frame | |
5722 | @itemx f | |
5723 | When used without any argument, this command does not change which | |
5724 | frame is selected, but prints a brief description of the currently | |
5725 | selected stack frame. It can be abbreviated @code{f}. With an | |
5726 | argument, this command is used to select a stack frame. | |
79a6e687 | 5727 | @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5728 | |
5729 | @kindex info frame | |
41afff9a | 5730 | @kindex info f @r{(@code{info frame})} |
c906108c SS |
5731 | @item info frame |
5732 | @itemx info f | |
5733 | This command prints a verbose description of the selected stack frame, | |
5734 | including: | |
5735 | ||
5736 | @itemize @bullet | |
5d161b24 DB |
5737 | @item |
5738 | the address of the frame | |
c906108c SS |
5739 | @item |
5740 | the address of the next frame down (called by this frame) | |
5741 | @item | |
5742 | the address of the next frame up (caller of this frame) | |
5743 | @item | |
5744 | the language in which the source code corresponding to this frame is written | |
5745 | @item | |
5746 | the address of the frame's arguments | |
5747 | @item | |
d4f3574e SS |
5748 | the address of the frame's local variables |
5749 | @item | |
c906108c SS |
5750 | the program counter saved in it (the address of execution in the caller frame) |
5751 | @item | |
5752 | which registers were saved in the frame | |
5753 | @end itemize | |
5754 | ||
5755 | @noindent The verbose description is useful when | |
5756 | something has gone wrong that has made the stack format fail to fit | |
5757 | the usual conventions. | |
5758 | ||
5759 | @item info frame @var{addr} | |
5760 | @itemx info f @var{addr} | |
5761 | Print a verbose description of the frame at address @var{addr}, without | |
5762 | selecting that frame. The selected frame remains unchanged by this | |
5763 | command. This requires the same kind of address (more than one for some | |
5764 | architectures) that you specify in the @code{frame} command. | |
79a6e687 | 5765 | @xref{Selection, ,Selecting a Frame}. |
c906108c SS |
5766 | |
5767 | @kindex info args | |
5768 | @item info args | |
5769 | Print the arguments of the selected frame, each on a separate line. | |
5770 | ||
5771 | @item info locals | |
5772 | @kindex info locals | |
5773 | Print the local variables of the selected frame, each on a separate | |
5774 | line. These are all variables (declared either static or automatic) | |
5775 | accessible at the point of execution of the selected frame. | |
5776 | ||
c906108c | 5777 | @kindex info catch |
d4f3574e SS |
5778 | @cindex catch exceptions, list active handlers |
5779 | @cindex exception handlers, how to list | |
c906108c SS |
5780 | @item info catch |
5781 | Print a list of all the exception handlers that are active in the | |
5782 | current stack frame at the current point of execution. To see other | |
5783 | exception handlers, visit the associated frame (using the @code{up}, | |
5784 | @code{down}, or @code{frame} commands); then type @code{info catch}. | |
79a6e687 | 5785 | @xref{Set Catchpoints, , Setting Catchpoints}. |
53a5351d | 5786 | |
c906108c SS |
5787 | @end table |
5788 | ||
c906108c | 5789 | |
6d2ebf8b | 5790 | @node Source |
c906108c SS |
5791 | @chapter Examining Source Files |
5792 | ||
5793 | @value{GDBN} can print parts of your program's source, since the debugging | |
5794 | information recorded in the program tells @value{GDBN} what source files were | |
5795 | used to build it. When your program stops, @value{GDBN} spontaneously prints | |
5796 | the line where it stopped. Likewise, when you select a stack frame | |
79a6e687 | 5797 | (@pxref{Selection, ,Selecting a Frame}), @value{GDBN} prints the line where |
c906108c SS |
5798 | execution in that frame has stopped. You can print other portions of |
5799 | source files by explicit command. | |
5800 | ||
7a292a7a | 5801 | If you use @value{GDBN} through its @sc{gnu} Emacs interface, you may |
d4f3574e | 5802 | prefer to use Emacs facilities to view source; see @ref{Emacs, ,Using |
7a292a7a | 5803 | @value{GDBN} under @sc{gnu} Emacs}. |
c906108c SS |
5804 | |
5805 | @menu | |
5806 | * List:: Printing source lines | |
2a25a5ba | 5807 | * Specify Location:: How to specify code locations |
87885426 | 5808 | * Edit:: Editing source files |
c906108c | 5809 | * Search:: Searching source files |
c906108c SS |
5810 | * Source Path:: Specifying source directories |
5811 | * Machine Code:: Source and machine code | |
5812 | @end menu | |
5813 | ||
6d2ebf8b | 5814 | @node List |
79a6e687 | 5815 | @section Printing Source Lines |
c906108c SS |
5816 | |
5817 | @kindex list | |
41afff9a | 5818 | @kindex l @r{(@code{list})} |
c906108c | 5819 | To print lines from a source file, use the @code{list} command |
5d161b24 | 5820 | (abbreviated @code{l}). By default, ten lines are printed. |
2a25a5ba EZ |
5821 | There are several ways to specify what part of the file you want to |
5822 | print; see @ref{Specify Location}, for the full list. | |
c906108c SS |
5823 | |
5824 | Here are the forms of the @code{list} command most commonly used: | |
5825 | ||
5826 | @table @code | |
5827 | @item list @var{linenum} | |
5828 | Print lines centered around line number @var{linenum} in the | |
5829 | current source file. | |
5830 | ||
5831 | @item list @var{function} | |
5832 | Print lines centered around the beginning of function | |
5833 | @var{function}. | |
5834 | ||
5835 | @item list | |
5836 | Print more lines. If the last lines printed were printed with a | |
5837 | @code{list} command, this prints lines following the last lines | |
5838 | printed; however, if the last line printed was a solitary line printed | |
5839 | as part of displaying a stack frame (@pxref{Stack, ,Examining the | |
5840 | Stack}), this prints lines centered around that line. | |
5841 | ||
5842 | @item list - | |
5843 | Print lines just before the lines last printed. | |
5844 | @end table | |
5845 | ||
9c16f35a | 5846 | @cindex @code{list}, how many lines to display |
c906108c SS |
5847 | By default, @value{GDBN} prints ten source lines with any of these forms of |
5848 | the @code{list} command. You can change this using @code{set listsize}: | |
5849 | ||
5850 | @table @code | |
5851 | @kindex set listsize | |
5852 | @item set listsize @var{count} | |
5853 | Make the @code{list} command display @var{count} source lines (unless | |
5854 | the @code{list} argument explicitly specifies some other number). | |
5855 | ||
5856 | @kindex show listsize | |
5857 | @item show listsize | |
5858 | Display the number of lines that @code{list} prints. | |
5859 | @end table | |
5860 | ||
5861 | Repeating a @code{list} command with @key{RET} discards the argument, | |
5862 | so it is equivalent to typing just @code{list}. This is more useful | |
5863 | than listing the same lines again. An exception is made for an | |
5864 | argument of @samp{-}; that argument is preserved in repetition so that | |
5865 | each repetition moves up in the source file. | |
5866 | ||
c906108c SS |
5867 | In general, the @code{list} command expects you to supply zero, one or two |
5868 | @dfn{linespecs}. Linespecs specify source lines; there are several ways | |
2a25a5ba EZ |
5869 | of writing them (@pxref{Specify Location}), but the effect is always |
5870 | to specify some source line. | |
5871 | ||
c906108c SS |
5872 | Here is a complete description of the possible arguments for @code{list}: |
5873 | ||
5874 | @table @code | |
5875 | @item list @var{linespec} | |
5876 | Print lines centered around the line specified by @var{linespec}. | |
5877 | ||
5878 | @item list @var{first},@var{last} | |
5879 | Print lines from @var{first} to @var{last}. Both arguments are | |
2a25a5ba EZ |
5880 | linespecs. When a @code{list} command has two linespecs, and the |
5881 | source file of the second linespec is omitted, this refers to | |
5882 | the same source file as the first linespec. | |
c906108c SS |
5883 | |
5884 | @item list ,@var{last} | |
5885 | Print lines ending with @var{last}. | |
5886 | ||
5887 | @item list @var{first}, | |
5888 | Print lines starting with @var{first}. | |
5889 | ||
5890 | @item list + | |
5891 | Print lines just after the lines last printed. | |
5892 | ||
5893 | @item list - | |
5894 | Print lines just before the lines last printed. | |
5895 | ||
5896 | @item list | |
5897 | As described in the preceding table. | |
5898 | @end table | |
5899 | ||
2a25a5ba EZ |
5900 | @node Specify Location |
5901 | @section Specifying a Location | |
5902 | @cindex specifying location | |
5903 | @cindex linespec | |
c906108c | 5904 | |
2a25a5ba EZ |
5905 | Several @value{GDBN} commands accept arguments that specify a location |
5906 | of your program's code. Since @value{GDBN} is a source-level | |
5907 | debugger, a location usually specifies some line in the source code; | |
5908 | for that reason, locations are also known as @dfn{linespecs}. | |
c906108c | 5909 | |
2a25a5ba EZ |
5910 | Here are all the different ways of specifying a code location that |
5911 | @value{GDBN} understands: | |
c906108c | 5912 | |
2a25a5ba EZ |
5913 | @table @code |
5914 | @item @var{linenum} | |
5915 | Specifies the line number @var{linenum} of the current source file. | |
c906108c | 5916 | |
2a25a5ba EZ |
5917 | @item -@var{offset} |
5918 | @itemx +@var{offset} | |
5919 | Specifies the line @var{offset} lines before or after the @dfn{current | |
5920 | line}. For the @code{list} command, the current line is the last one | |
5921 | printed; for the breakpoint commands, this is the line at which | |
5922 | execution stopped in the currently selected @dfn{stack frame} | |
5923 | (@pxref{Frames, ,Frames}, for a description of stack frames.) When | |
5924 | used as the second of the two linespecs in a @code{list} command, | |
5925 | this specifies the line @var{offset} lines up or down from the first | |
5926 | linespec. | |
5927 | ||
5928 | @item @var{filename}:@var{linenum} | |
5929 | Specifies the line @var{linenum} in the source file @var{filename}. | |
c906108c SS |
5930 | |
5931 | @item @var{function} | |
5932 | Specifies the line that begins the body of the function @var{function}. | |
2a25a5ba | 5933 | For example, in C, this is the line with the open brace. |
c906108c SS |
5934 | |
5935 | @item @var{filename}:@var{function} | |
2a25a5ba EZ |
5936 | Specifies the line that begins the body of the function @var{function} |
5937 | in the file @var{filename}. You only need the file name with a | |
5938 | function name to avoid ambiguity when there are identically named | |
5939 | functions in different source files. | |
c906108c SS |
5940 | |
5941 | @item *@var{address} | |
2a25a5ba EZ |
5942 | Specifies the program address @var{address}. For line-oriented |
5943 | commands, such as @code{list} and @code{edit}, this specifies a source | |
5944 | line that contains @var{address}. For @code{break} and other | |
5945 | breakpoint oriented commands, this can be used to set breakpoints in | |
5946 | parts of your program which do not have debugging information or | |
5947 | source files. | |
5948 | ||
5949 | Here @var{address} may be any expression valid in the current working | |
5950 | language (@pxref{Languages, working language}) that specifies a code | |
5fa54e5d EZ |
5951 | address. In addition, as a convenience, @value{GDBN} extends the |
5952 | semantics of expressions used in locations to cover the situations | |
5953 | that frequently happen during debugging. Here are the various forms | |
5954 | of @var{address}: | |
2a25a5ba EZ |
5955 | |
5956 | @table @code | |
5957 | @item @var{expression} | |
5958 | Any expression valid in the current working language. | |
5959 | ||
5960 | @item @var{funcaddr} | |
5961 | An address of a function or procedure derived from its name. In C, | |
5962 | C@t{++}, Java, Objective-C, Fortran, minimal, and assembly, this is | |
5963 | simply the function's name @var{function} (and actually a special case | |
5964 | of a valid expression). In Pascal and Modula-2, this is | |
5965 | @code{&@var{function}}. In Ada, this is @code{@var{function}'Address} | |
5966 | (although the Pascal form also works). | |
5967 | ||
5968 | This form specifies the address of the function's first instruction, | |
5969 | before the stack frame and arguments have been set up. | |
5970 | ||
5971 | @item '@var{filename}'::@var{funcaddr} | |
5972 | Like @var{funcaddr} above, but also specifies the name of the source | |
5973 | file explicitly. This is useful if the name of the function does not | |
5974 | specify the function unambiguously, e.g., if there are several | |
5975 | functions with identical names in different source files. | |
c906108c SS |
5976 | @end table |
5977 | ||
2a25a5ba EZ |
5978 | @end table |
5979 | ||
5980 | ||
87885426 | 5981 | @node Edit |
79a6e687 | 5982 | @section Editing Source Files |
87885426 FN |
5983 | @cindex editing source files |
5984 | ||
5985 | @kindex edit | |
5986 | @kindex e @r{(@code{edit})} | |
5987 | To edit the lines in a source file, use the @code{edit} command. | |
5988 | The editing program of your choice | |
5989 | is invoked with the current line set to | |
5990 | the active line in the program. | |
5991 | Alternatively, there are several ways to specify what part of the file you | |
2a25a5ba | 5992 | want to print if you want to see other parts of the program: |
87885426 FN |
5993 | |
5994 | @table @code | |
2a25a5ba EZ |
5995 | @item edit @var{location} |
5996 | Edit the source file specified by @code{location}. Editing starts at | |
5997 | that @var{location}, e.g., at the specified source line of the | |
5998 | specified file. @xref{Specify Location}, for all the possible forms | |
5999 | of the @var{location} argument; here are the forms of the @code{edit} | |
6000 | command most commonly used: | |
87885426 | 6001 | |
2a25a5ba | 6002 | @table @code |
87885426 FN |
6003 | @item edit @var{number} |
6004 | Edit the current source file with @var{number} as the active line number. | |
6005 | ||
6006 | @item edit @var{function} | |
6007 | Edit the file containing @var{function} at the beginning of its definition. | |
2a25a5ba | 6008 | @end table |
87885426 | 6009 | |
87885426 FN |
6010 | @end table |
6011 | ||
79a6e687 | 6012 | @subsection Choosing your Editor |
87885426 FN |
6013 | You can customize @value{GDBN} to use any editor you want |
6014 | @footnote{ | |
6015 | The only restriction is that your editor (say @code{ex}), recognizes the | |
6016 | following command-line syntax: | |
10998722 | 6017 | @smallexample |
87885426 | 6018 | ex +@var{number} file |
10998722 | 6019 | @end smallexample |
15387254 EZ |
6020 | The optional numeric value +@var{number} specifies the number of the line in |
6021 | the file where to start editing.}. | |
6022 | By default, it is @file{@value{EDITOR}}, but you can change this | |
10998722 AC |
6023 | by setting the environment variable @code{EDITOR} before using |
6024 | @value{GDBN}. For example, to configure @value{GDBN} to use the | |
6025 | @code{vi} editor, you could use these commands with the @code{sh} shell: | |
6026 | @smallexample | |
87885426 FN |
6027 | EDITOR=/usr/bin/vi |
6028 | export EDITOR | |
15387254 | 6029 | gdb @dots{} |
10998722 | 6030 | @end smallexample |
87885426 | 6031 | or in the @code{csh} shell, |
10998722 | 6032 | @smallexample |
87885426 | 6033 | setenv EDITOR /usr/bin/vi |
15387254 | 6034 | gdb @dots{} |
10998722 | 6035 | @end smallexample |
87885426 | 6036 | |
6d2ebf8b | 6037 | @node Search |
79a6e687 | 6038 | @section Searching Source Files |
15387254 | 6039 | @cindex searching source files |
c906108c SS |
6040 | |
6041 | There are two commands for searching through the current source file for a | |
6042 | regular expression. | |
6043 | ||
6044 | @table @code | |
6045 | @kindex search | |
6046 | @kindex forward-search | |
6047 | @item forward-search @var{regexp} | |
6048 | @itemx search @var{regexp} | |
6049 | The command @samp{forward-search @var{regexp}} checks each line, | |
6050 | starting with the one following the last line listed, for a match for | |
5d161b24 | 6051 | @var{regexp}. It lists the line that is found. You can use the |
c906108c SS |
6052 | synonym @samp{search @var{regexp}} or abbreviate the command name as |
6053 | @code{fo}. | |
6054 | ||
09d4efe1 | 6055 | @kindex reverse-search |
c906108c SS |
6056 | @item reverse-search @var{regexp} |
6057 | The command @samp{reverse-search @var{regexp}} checks each line, starting | |
6058 | with the one before the last line listed and going backward, for a match | |
6059 | for @var{regexp}. It lists the line that is found. You can abbreviate | |
6060 | this command as @code{rev}. | |
6061 | @end table | |
c906108c | 6062 | |
6d2ebf8b | 6063 | @node Source Path |
79a6e687 | 6064 | @section Specifying Source Directories |
c906108c SS |
6065 | |
6066 | @cindex source path | |
6067 | @cindex directories for source files | |
6068 | Executable programs sometimes do not record the directories of the source | |
6069 | files from which they were compiled, just the names. Even when they do, | |
6070 | the directories could be moved between the compilation and your debugging | |
6071 | session. @value{GDBN} has a list of directories to search for source files; | |
6072 | this is called the @dfn{source path}. Each time @value{GDBN} wants a source file, | |
6073 | it tries all the directories in the list, in the order they are present | |
0b66e38c EZ |
6074 | in the list, until it finds a file with the desired name. |
6075 | ||
6076 | For example, suppose an executable references the file | |
6077 | @file{/usr/src/foo-1.0/lib/foo.c}, and our source path is | |
6078 | @file{/mnt/cross}. The file is first looked up literally; if this | |
6079 | fails, @file{/mnt/cross/usr/src/foo-1.0/lib/foo.c} is tried; if this | |
6080 | fails, @file{/mnt/cross/foo.c} is opened; if this fails, an error | |
6081 | message is printed. @value{GDBN} does not look up the parts of the | |
6082 | source file name, such as @file{/mnt/cross/src/foo-1.0/lib/foo.c}. | |
6083 | Likewise, the subdirectories of the source path are not searched: if | |
6084 | the source path is @file{/mnt/cross}, and the binary refers to | |
6085 | @file{foo.c}, @value{GDBN} would not find it under | |
6086 | @file{/mnt/cross/usr/src/foo-1.0/lib}. | |
6087 | ||
6088 | Plain file names, relative file names with leading directories, file | |
6089 | names containing dots, etc.@: are all treated as described above; for | |
6090 | instance, if the source path is @file{/mnt/cross}, and the source file | |
6091 | is recorded as @file{../lib/foo.c}, @value{GDBN} would first try | |
6092 | @file{../lib/foo.c}, then @file{/mnt/cross/../lib/foo.c}, and after | |
6093 | that---@file{/mnt/cross/foo.c}. | |
6094 | ||
6095 | Note that the executable search path is @emph{not} used to locate the | |
cd852561 | 6096 | source files. |
c906108c SS |
6097 | |
6098 | Whenever you reset or rearrange the source path, @value{GDBN} clears out | |
6099 | any information it has cached about where source files are found and where | |
6100 | each line is in the file. | |
6101 | ||
6102 | @kindex directory | |
6103 | @kindex dir | |
d4f3574e SS |
6104 | When you start @value{GDBN}, its source path includes only @samp{cdir} |
6105 | and @samp{cwd}, in that order. | |
c906108c SS |
6106 | To add other directories, use the @code{directory} command. |
6107 | ||
4b505b12 AS |
6108 | The search path is used to find both program source files and @value{GDBN} |
6109 | script files (read using the @samp{-command} option and @samp{source} command). | |
6110 | ||
30daae6c JB |
6111 | In addition to the source path, @value{GDBN} provides a set of commands |
6112 | that manage a list of source path substitution rules. A @dfn{substitution | |
6113 | rule} specifies how to rewrite source directories stored in the program's | |
6114 | debug information in case the sources were moved to a different | |
6115 | directory between compilation and debugging. A rule is made of | |
6116 | two strings, the first specifying what needs to be rewritten in | |
6117 | the path, and the second specifying how it should be rewritten. | |
6118 | In @ref{set substitute-path}, we name these two parts @var{from} and | |
6119 | @var{to} respectively. @value{GDBN} does a simple string replacement | |
6120 | of @var{from} with @var{to} at the start of the directory part of the | |
6121 | source file name, and uses that result instead of the original file | |
6122 | name to look up the sources. | |
6123 | ||
6124 | Using the previous example, suppose the @file{foo-1.0} tree has been | |
6125 | moved from @file{/usr/src} to @file{/mnt/cross}, then you can tell | |
3f94c067 | 6126 | @value{GDBN} to replace @file{/usr/src} in all source path names with |
30daae6c JB |
6127 | @file{/mnt/cross}. The first lookup will then be |
6128 | @file{/mnt/cross/foo-1.0/lib/foo.c} in place of the original location | |
6129 | of @file{/usr/src/foo-1.0/lib/foo.c}. To define a source path | |
6130 | substitution rule, use the @code{set substitute-path} command | |
6131 | (@pxref{set substitute-path}). | |
6132 | ||
6133 | To avoid unexpected substitution results, a rule is applied only if the | |
6134 | @var{from} part of the directory name ends at a directory separator. | |
6135 | For instance, a rule substituting @file{/usr/source} into | |
6136 | @file{/mnt/cross} will be applied to @file{/usr/source/foo-1.0} but | |
6137 | not to @file{/usr/sourceware/foo-2.0}. And because the substitution | |
d3e8051b | 6138 | is applied only at the beginning of the directory name, this rule will |
30daae6c JB |
6139 | not be applied to @file{/root/usr/source/baz.c} either. |
6140 | ||
6141 | In many cases, you can achieve the same result using the @code{directory} | |
6142 | command. However, @code{set substitute-path} can be more efficient in | |
6143 | the case where the sources are organized in a complex tree with multiple | |
6144 | subdirectories. With the @code{directory} command, you need to add each | |
6145 | subdirectory of your project. If you moved the entire tree while | |
6146 | preserving its internal organization, then @code{set substitute-path} | |
6147 | allows you to direct the debugger to all the sources with one single | |
6148 | command. | |
6149 | ||
6150 | @code{set substitute-path} is also more than just a shortcut command. | |
6151 | The source path is only used if the file at the original location no | |
6152 | longer exists. On the other hand, @code{set substitute-path} modifies | |
6153 | the debugger behavior to look at the rewritten location instead. So, if | |
6154 | for any reason a source file that is not relevant to your executable is | |
6155 | located at the original location, a substitution rule is the only | |
3f94c067 | 6156 | method available to point @value{GDBN} at the new location. |
30daae6c | 6157 | |
29b0e8a2 JM |
6158 | @cindex @samp{--with-relocated-sources} |
6159 | @cindex default source path substitution | |
6160 | You can configure a default source path substitution rule by | |
6161 | configuring @value{GDBN} with the | |
6162 | @samp{--with-relocated-sources=@var{dir}} option. The @var{dir} | |
6163 | should be the name of a directory under @value{GDBN}'s configured | |
6164 | prefix (set with @samp{--prefix} or @samp{--exec-prefix}), and | |
6165 | directory names in debug information under @var{dir} will be adjusted | |
6166 | automatically if the installed @value{GDBN} is moved to a new | |
6167 | location. This is useful if @value{GDBN}, libraries or executables | |
6168 | with debug information and corresponding source code are being moved | |
6169 | together. | |
6170 | ||
c906108c SS |
6171 | @table @code |
6172 | @item directory @var{dirname} @dots{} | |
6173 | @item dir @var{dirname} @dots{} | |
6174 | Add directory @var{dirname} to the front of the source path. Several | |
d4f3574e SS |
6175 | directory names may be given to this command, separated by @samp{:} |
6176 | (@samp{;} on MS-DOS and MS-Windows, where @samp{:} usually appears as | |
6177 | part of absolute file names) or | |
c906108c SS |
6178 | whitespace. You may specify a directory that is already in the source |
6179 | path; this moves it forward, so @value{GDBN} searches it sooner. | |
6180 | ||
6181 | @kindex cdir | |
6182 | @kindex cwd | |
41afff9a | 6183 | @vindex $cdir@r{, convenience variable} |
d3e8051b | 6184 | @vindex $cwd@r{, convenience variable} |
c906108c SS |
6185 | @cindex compilation directory |
6186 | @cindex current directory | |
6187 | @cindex working directory | |
6188 | @cindex directory, current | |
6189 | @cindex directory, compilation | |
6190 | You can use the string @samp{$cdir} to refer to the compilation | |
6191 | directory (if one is recorded), and @samp{$cwd} to refer to the current | |
6192 | working directory. @samp{$cwd} is not the same as @samp{.}---the former | |
6193 | tracks the current working directory as it changes during your @value{GDBN} | |
6194 | session, while the latter is immediately expanded to the current | |
6195 | directory at the time you add an entry to the source path. | |
6196 | ||
6197 | @item directory | |
cd852561 | 6198 | Reset the source path to its default value (@samp{$cdir:$cwd} on Unix systems). This requires confirmation. |
c906108c SS |
6199 | |
6200 | @c RET-repeat for @code{directory} is explicitly disabled, but since | |
6201 | @c repeating it would be a no-op we do not say that. (thanks to RMS) | |
6202 | ||
6203 | @item show directories | |
6204 | @kindex show directories | |
6205 | Print the source path: show which directories it contains. | |
30daae6c JB |
6206 | |
6207 | @anchor{set substitute-path} | |
6208 | @item set substitute-path @var{from} @var{to} | |
6209 | @kindex set substitute-path | |
6210 | Define a source path substitution rule, and add it at the end of the | |
6211 | current list of existing substitution rules. If a rule with the same | |
6212 | @var{from} was already defined, then the old rule is also deleted. | |
6213 | ||
6214 | For example, if the file @file{/foo/bar/baz.c} was moved to | |
6215 | @file{/mnt/cross/baz.c}, then the command | |
6216 | ||
6217 | @smallexample | |
6218 | (@value{GDBP}) set substitute-path /usr/src /mnt/cross | |
6219 | @end smallexample | |
6220 | ||
6221 | @noindent | |
6222 | will tell @value{GDBN} to replace @samp{/usr/src} with | |
6223 | @samp{/mnt/cross}, which will allow @value{GDBN} to find the file | |
6224 | @file{baz.c} even though it was moved. | |
6225 | ||
6226 | In the case when more than one substitution rule have been defined, | |
6227 | the rules are evaluated one by one in the order where they have been | |
6228 | defined. The first one matching, if any, is selected to perform | |
6229 | the substitution. | |
6230 | ||
6231 | For instance, if we had entered the following commands: | |
6232 | ||
6233 | @smallexample | |
6234 | (@value{GDBP}) set substitute-path /usr/src/include /mnt/include | |
6235 | (@value{GDBP}) set substitute-path /usr/src /mnt/src | |
6236 | @end smallexample | |
6237 | ||
6238 | @noindent | |
6239 | @value{GDBN} would then rewrite @file{/usr/src/include/defs.h} into | |
6240 | @file{/mnt/include/defs.h} by using the first rule. However, it would | |
6241 | use the second rule to rewrite @file{/usr/src/lib/foo.c} into | |
6242 | @file{/mnt/src/lib/foo.c}. | |
6243 | ||
6244 | ||
6245 | @item unset substitute-path [path] | |
6246 | @kindex unset substitute-path | |
6247 | If a path is specified, search the current list of substitution rules | |
6248 | for a rule that would rewrite that path. Delete that rule if found. | |
6249 | A warning is emitted by the debugger if no rule could be found. | |
6250 | ||
6251 | If no path is specified, then all substitution rules are deleted. | |
6252 | ||
6253 | @item show substitute-path [path] | |
6254 | @kindex show substitute-path | |
6255 | If a path is specified, then print the source path substitution rule | |
6256 | which would rewrite that path, if any. | |
6257 | ||
6258 | If no path is specified, then print all existing source path substitution | |
6259 | rules. | |
6260 | ||
c906108c SS |
6261 | @end table |
6262 | ||
6263 | If your source path is cluttered with directories that are no longer of | |
6264 | interest, @value{GDBN} may sometimes cause confusion by finding the wrong | |
6265 | versions of source. You can correct the situation as follows: | |
6266 | ||
6267 | @enumerate | |
6268 | @item | |
cd852561 | 6269 | Use @code{directory} with no argument to reset the source path to its default value. |
c906108c SS |
6270 | |
6271 | @item | |
6272 | Use @code{directory} with suitable arguments to reinstall the | |
6273 | directories you want in the source path. You can add all the | |
6274 | directories in one command. | |
6275 | @end enumerate | |
6276 | ||
6d2ebf8b | 6277 | @node Machine Code |
79a6e687 | 6278 | @section Source and Machine Code |
15387254 | 6279 | @cindex source line and its code address |
c906108c SS |
6280 | |
6281 | You can use the command @code{info line} to map source lines to program | |
6282 | addresses (and vice versa), and the command @code{disassemble} to display | |
91440f57 HZ |
6283 | a range of addresses as machine instructions. You can use the command |
6284 | @code{set disassemble-next-line} to set whether to disassemble next | |
6285 | source line when execution stops. When run under @sc{gnu} Emacs | |
d4f3574e | 6286 | mode, the @code{info line} command causes the arrow to point to the |
5d161b24 | 6287 | line specified. Also, @code{info line} prints addresses in symbolic form as |
c906108c SS |
6288 | well as hex. |
6289 | ||
6290 | @table @code | |
6291 | @kindex info line | |
6292 | @item info line @var{linespec} | |
6293 | Print the starting and ending addresses of the compiled code for | |
6294 | source line @var{linespec}. You can specify source lines in any of | |
2a25a5ba | 6295 | the ways documented in @ref{Specify Location}. |
c906108c SS |
6296 | @end table |
6297 | ||
6298 | For example, we can use @code{info line} to discover the location of | |
6299 | the object code for the first line of function | |
6300 | @code{m4_changequote}: | |
6301 | ||
d4f3574e SS |
6302 | @c FIXME: I think this example should also show the addresses in |
6303 | @c symbolic form, as they usually would be displayed. | |
c906108c | 6304 | @smallexample |
96a2c332 | 6305 | (@value{GDBP}) info line m4_changequote |
c906108c SS |
6306 | Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350. |
6307 | @end smallexample | |
6308 | ||
6309 | @noindent | |
15387254 | 6310 | @cindex code address and its source line |
c906108c SS |
6311 | We can also inquire (using @code{*@var{addr}} as the form for |
6312 | @var{linespec}) what source line covers a particular address: | |
6313 | @smallexample | |
6314 | (@value{GDBP}) info line *0x63ff | |
6315 | Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404. | |
6316 | @end smallexample | |
6317 | ||
6318 | @cindex @code{$_} and @code{info line} | |
15387254 | 6319 | @cindex @code{x} command, default address |
41afff9a | 6320 | @kindex x@r{(examine), and} info line |
c906108c SS |
6321 | After @code{info line}, the default address for the @code{x} command |
6322 | is changed to the starting address of the line, so that @samp{x/i} is | |
6323 | sufficient to begin examining the machine code (@pxref{Memory, | |
79a6e687 | 6324 | ,Examining Memory}). Also, this address is saved as the value of the |
c906108c | 6325 | convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience |
79a6e687 | 6326 | Variables}). |
c906108c SS |
6327 | |
6328 | @table @code | |
6329 | @kindex disassemble | |
6330 | @cindex assembly instructions | |
6331 | @cindex instructions, assembly | |
6332 | @cindex machine instructions | |
6333 | @cindex listing machine instructions | |
6334 | @item disassemble | |
d14508fe | 6335 | @itemx disassemble /m |
9b117ef3 | 6336 | @itemx disassemble /r |
c906108c | 6337 | This specialized command dumps a range of memory as machine |
d14508fe | 6338 | instructions. It can also print mixed source+disassembly by specifying |
9b117ef3 HZ |
6339 | the @code{/m} modifier and print the raw instructions in hex as well as |
6340 | in symbolic form by specifying the @code{/r}. | |
d14508fe | 6341 | The default memory range is the function surrounding the |
c906108c SS |
6342 | program counter of the selected frame. A single argument to this |
6343 | command is a program counter value; @value{GDBN} dumps the function | |
6344 | surrounding this value. Two arguments specify a range of addresses | |
6345 | (first inclusive, second exclusive) to dump. | |
6346 | @end table | |
6347 | ||
c906108c SS |
6348 | The following example shows the disassembly of a range of addresses of |
6349 | HP PA-RISC 2.0 code: | |
6350 | ||
6351 | @smallexample | |
6352 | (@value{GDBP}) disas 0x32c4 0x32e4 | |
6353 | Dump of assembler code from 0x32c4 to 0x32e4: | |
6354 | 0x32c4 <main+204>: addil 0,dp | |
6355 | 0x32c8 <main+208>: ldw 0x22c(sr0,r1),r26 | |
6356 | 0x32cc <main+212>: ldil 0x3000,r31 | |
6357 | 0x32d0 <main+216>: ble 0x3f8(sr4,r31) | |
6358 | 0x32d4 <main+220>: ldo 0(r31),rp | |
6359 | 0x32d8 <main+224>: addil -0x800,dp | |
6360 | 0x32dc <main+228>: ldo 0x588(r1),r26 | |
6361 | 0x32e0 <main+232>: ldil 0x3000,r31 | |
6362 | End of assembler dump. | |
6363 | @end smallexample | |
c906108c | 6364 | |
d14508fe DE |
6365 | Here is an example showing mixed source+assembly for Intel x86: |
6366 | ||
6367 | @smallexample | |
6368 | (@value{GDBP}) disas /m main | |
6369 | Dump of assembler code for function main: | |
6370 | 5 @{ | |
6371 | 0x08048330 <main+0>: push %ebp | |
6372 | 0x08048331 <main+1>: mov %esp,%ebp | |
6373 | 0x08048333 <main+3>: sub $0x8,%esp | |
6374 | 0x08048336 <main+6>: and $0xfffffff0,%esp | |
6375 | 0x08048339 <main+9>: sub $0x10,%esp | |
6376 | ||
6377 | 6 printf ("Hello.\n"); | |
6378 | 0x0804833c <main+12>: movl $0x8048440,(%esp) | |
6379 | 0x08048343 <main+19>: call 0x8048284 <puts@@plt> | |
6380 | ||
6381 | 7 return 0; | |
6382 | 8 @} | |
6383 | 0x08048348 <main+24>: mov $0x0,%eax | |
6384 | 0x0804834d <main+29>: leave | |
6385 | 0x0804834e <main+30>: ret | |
6386 | ||
6387 | End of assembler dump. | |
6388 | @end smallexample | |
6389 | ||
c906108c SS |
6390 | Some architectures have more than one commonly-used set of instruction |
6391 | mnemonics or other syntax. | |
6392 | ||
76d17f34 EZ |
6393 | For programs that were dynamically linked and use shared libraries, |
6394 | instructions that call functions or branch to locations in the shared | |
6395 | libraries might show a seemingly bogus location---it's actually a | |
6396 | location of the relocation table. On some architectures, @value{GDBN} | |
6397 | might be able to resolve these to actual function names. | |
6398 | ||
c906108c | 6399 | @table @code |
d4f3574e | 6400 | @kindex set disassembly-flavor |
d4f3574e SS |
6401 | @cindex Intel disassembly flavor |
6402 | @cindex AT&T disassembly flavor | |
6403 | @item set disassembly-flavor @var{instruction-set} | |
c906108c SS |
6404 | Select the instruction set to use when disassembling the |
6405 | program via the @code{disassemble} or @code{x/i} commands. | |
6406 | ||
6407 | Currently this command is only defined for the Intel x86 family. You | |
d4f3574e SS |
6408 | can set @var{instruction-set} to either @code{intel} or @code{att}. |
6409 | The default is @code{att}, the AT&T flavor used by default by Unix | |
6410 | assemblers for x86-based targets. | |
9c16f35a EZ |
6411 | |
6412 | @kindex show disassembly-flavor | |
6413 | @item show disassembly-flavor | |
6414 | Show the current setting of the disassembly flavor. | |
c906108c SS |
6415 | @end table |
6416 | ||
91440f57 HZ |
6417 | @table @code |
6418 | @kindex set disassemble-next-line | |
6419 | @kindex show disassemble-next-line | |
6420 | @item set disassemble-next-line | |
6421 | @itemx show disassemble-next-line | |
32ae1842 EZ |
6422 | Control whether or not @value{GDBN} will disassemble the next source |
6423 | line or instruction when execution stops. If ON, @value{GDBN} will | |
6424 | display disassembly of the next source line when execution of the | |
6425 | program being debugged stops. This is @emph{in addition} to | |
6426 | displaying the source line itself, which @value{GDBN} always does if | |
6427 | possible. If the next source line cannot be displayed for some reason | |
6428 | (e.g., if @value{GDBN} cannot find the source file, or there's no line | |
6429 | info in the debug info), @value{GDBN} will display disassembly of the | |
6430 | next @emph{instruction} instead of showing the next source line. If | |
6431 | AUTO, @value{GDBN} will display disassembly of next instruction only | |
6432 | if the source line cannot be displayed. This setting causes | |
6433 | @value{GDBN} to display some feedback when you step through a function | |
6434 | with no line info or whose source file is unavailable. The default is | |
6435 | OFF, which means never display the disassembly of the next line or | |
6436 | instruction. | |
91440f57 HZ |
6437 | @end table |
6438 | ||
c906108c | 6439 | |
6d2ebf8b | 6440 | @node Data |
c906108c SS |
6441 | @chapter Examining Data |
6442 | ||
6443 | @cindex printing data | |
6444 | @cindex examining data | |
6445 | @kindex print | |
6446 | @kindex inspect | |
6447 | @c "inspect" is not quite a synonym if you are using Epoch, which we do not | |
6448 | @c document because it is nonstandard... Under Epoch it displays in a | |
6449 | @c different window or something like that. | |
6450 | The usual way to examine data in your program is with the @code{print} | |
7a292a7a SS |
6451 | command (abbreviated @code{p}), or its synonym @code{inspect}. It |
6452 | evaluates and prints the value of an expression of the language your | |
6453 | program is written in (@pxref{Languages, ,Using @value{GDBN} with | |
6454 | Different Languages}). | |
c906108c SS |
6455 | |
6456 | @table @code | |
d4f3574e SS |
6457 | @item print @var{expr} |
6458 | @itemx print /@var{f} @var{expr} | |
6459 | @var{expr} is an expression (in the source language). By default the | |
6460 | value of @var{expr} is printed in a format appropriate to its data type; | |
c906108c | 6461 | you can choose a different format by specifying @samp{/@var{f}}, where |
d4f3574e | 6462 | @var{f} is a letter specifying the format; see @ref{Output Formats,,Output |
79a6e687 | 6463 | Formats}. |
c906108c SS |
6464 | |
6465 | @item print | |
6466 | @itemx print /@var{f} | |
15387254 | 6467 | @cindex reprint the last value |
d4f3574e | 6468 | If you omit @var{expr}, @value{GDBN} displays the last value again (from the |
79a6e687 | 6469 | @dfn{value history}; @pxref{Value History, ,Value History}). This allows you to |
c906108c SS |
6470 | conveniently inspect the same value in an alternative format. |
6471 | @end table | |
6472 | ||
6473 | A more low-level way of examining data is with the @code{x} command. | |
6474 | It examines data in memory at a specified address and prints it in a | |
79a6e687 | 6475 | specified format. @xref{Memory, ,Examining Memory}. |
c906108c | 6476 | |
7a292a7a | 6477 | If you are interested in information about types, or about how the |
d4f3574e SS |
6478 | fields of a struct or a class are declared, use the @code{ptype @var{exp}} |
6479 | command rather than @code{print}. @xref{Symbols, ,Examining the Symbol | |
7a292a7a | 6480 | Table}. |
c906108c SS |
6481 | |
6482 | @menu | |
6483 | * Expressions:: Expressions | |
6ba66d6a | 6484 | * Ambiguous Expressions:: Ambiguous Expressions |
c906108c SS |
6485 | * Variables:: Program variables |
6486 | * Arrays:: Artificial arrays | |
6487 | * Output Formats:: Output formats | |
6488 | * Memory:: Examining memory | |
6489 | * Auto Display:: Automatic display | |
6490 | * Print Settings:: Print settings | |
6491 | * Value History:: Value history | |
6492 | * Convenience Vars:: Convenience variables | |
6493 | * Registers:: Registers | |
c906108c | 6494 | * Floating Point Hardware:: Floating point hardware |
53c69bd7 | 6495 | * Vector Unit:: Vector Unit |
721c2651 | 6496 | * OS Information:: Auxiliary data provided by operating system |
29e57380 | 6497 | * Memory Region Attributes:: Memory region attributes |
16d9dec6 | 6498 | * Dump/Restore Files:: Copy between memory and a file |
384ee23f | 6499 | * Core File Generation:: Cause a program dump its core |
a0eb71c5 KB |
6500 | * Character Sets:: Debugging programs that use a different |
6501 | character set than GDB does | |
09d4efe1 | 6502 | * Caching Remote Data:: Data caching for remote targets |
08388c79 | 6503 | * Searching Memory:: Searching memory for a sequence of bytes |
c906108c SS |
6504 | @end menu |
6505 | ||
6d2ebf8b | 6506 | @node Expressions |
c906108c SS |
6507 | @section Expressions |
6508 | ||
6509 | @cindex expressions | |
6510 | @code{print} and many other @value{GDBN} commands accept an expression and | |
6511 | compute its value. Any kind of constant, variable or operator defined | |
6512 | by the programming language you are using is valid in an expression in | |
e2e0bcd1 JB |
6513 | @value{GDBN}. This includes conditional expressions, function calls, |
6514 | casts, and string constants. It also includes preprocessor macros, if | |
6515 | you compiled your program to include this information; see | |
6516 | @ref{Compilation}. | |
c906108c | 6517 | |
15387254 | 6518 | @cindex arrays in expressions |
d4f3574e SS |
6519 | @value{GDBN} supports array constants in expressions input by |
6520 | the user. The syntax is @{@var{element}, @var{element}@dots{}@}. For example, | |
63092375 DJ |
6521 | you can use the command @code{print @{1, 2, 3@}} to create an array |
6522 | of three integers. If you pass an array to a function or assign it | |
6523 | to a program variable, @value{GDBN} copies the array to memory that | |
6524 | is @code{malloc}ed in the target program. | |
c906108c | 6525 | |
c906108c SS |
6526 | Because C is so widespread, most of the expressions shown in examples in |
6527 | this manual are in C. @xref{Languages, , Using @value{GDBN} with Different | |
6528 | Languages}, for information on how to use expressions in other | |
6529 | languages. | |
6530 | ||
6531 | In this section, we discuss operators that you can use in @value{GDBN} | |
6532 | expressions regardless of your programming language. | |
6533 | ||
15387254 | 6534 | @cindex casts, in expressions |
c906108c SS |
6535 | Casts are supported in all languages, not just in C, because it is so |
6536 | useful to cast a number into a pointer in order to examine a structure | |
6537 | at that address in memory. | |
6538 | @c FIXME: casts supported---Mod2 true? | |
c906108c SS |
6539 | |
6540 | @value{GDBN} supports these operators, in addition to those common | |
6541 | to programming languages: | |
6542 | ||
6543 | @table @code | |
6544 | @item @@ | |
6545 | @samp{@@} is a binary operator for treating parts of memory as arrays. | |
79a6e687 | 6546 | @xref{Arrays, ,Artificial Arrays}, for more information. |
c906108c SS |
6547 | |
6548 | @item :: | |
6549 | @samp{::} allows you to specify a variable in terms of the file or | |
79a6e687 | 6550 | function where it is defined. @xref{Variables, ,Program Variables}. |
c906108c SS |
6551 | |
6552 | @cindex @{@var{type}@} | |
6553 | @cindex type casting memory | |
6554 | @cindex memory, viewing as typed object | |
6555 | @cindex casts, to view memory | |
6556 | @item @{@var{type}@} @var{addr} | |
6557 | Refers to an object of type @var{type} stored at address @var{addr} in | |
6558 | memory. @var{addr} may be any expression whose value is an integer or | |
6559 | pointer (but parentheses are required around binary operators, just as in | |
6560 | a cast). This construct is allowed regardless of what kind of data is | |
6561 | normally supposed to reside at @var{addr}. | |
6562 | @end table | |
6563 | ||
6ba66d6a JB |
6564 | @node Ambiguous Expressions |
6565 | @section Ambiguous Expressions | |
6566 | @cindex ambiguous expressions | |
6567 | ||
6568 | Expressions can sometimes contain some ambiguous elements. For instance, | |
6569 | some programming languages (notably Ada, C@t{++} and Objective-C) permit | |
6570 | a single function name to be defined several times, for application in | |
6571 | different contexts. This is called @dfn{overloading}. Another example | |
6572 | involving Ada is generics. A @dfn{generic package} is similar to C@t{++} | |
6573 | templates and is typically instantiated several times, resulting in | |
6574 | the same function name being defined in different contexts. | |
6575 | ||
6576 | In some cases and depending on the language, it is possible to adjust | |
6577 | the expression to remove the ambiguity. For instance in C@t{++}, you | |
6578 | can specify the signature of the function you want to break on, as in | |
6579 | @kbd{break @var{function}(@var{types})}. In Ada, using the fully | |
6580 | qualified name of your function often makes the expression unambiguous | |
6581 | as well. | |
6582 | ||
6583 | When an ambiguity that needs to be resolved is detected, the debugger | |
6584 | has the capability to display a menu of numbered choices for each | |
6585 | possibility, and then waits for the selection with the prompt @samp{>}. | |
6586 | The first option is always @samp{[0] cancel}, and typing @kbd{0 @key{RET}} | |
6587 | aborts the current command. If the command in which the expression was | |
6588 | used allows more than one choice to be selected, the next option in the | |
6589 | menu is @samp{[1] all}, and typing @kbd{1 @key{RET}} selects all possible | |
6590 | choices. | |
6591 | ||
6592 | For example, the following session excerpt shows an attempt to set a | |
6593 | breakpoint at the overloaded symbol @code{String::after}. | |
6594 | We choose three particular definitions of that function name: | |
6595 | ||
6596 | @c FIXME! This is likely to change to show arg type lists, at least | |
6597 | @smallexample | |
6598 | @group | |
6599 | (@value{GDBP}) b String::after | |
6600 | [0] cancel | |
6601 | [1] all | |
6602 | [2] file:String.cc; line number:867 | |
6603 | [3] file:String.cc; line number:860 | |
6604 | [4] file:String.cc; line number:875 | |
6605 | [5] file:String.cc; line number:853 | |
6606 | [6] file:String.cc; line number:846 | |
6607 | [7] file:String.cc; line number:735 | |
6608 | > 2 4 6 | |
6609 | Breakpoint 1 at 0xb26c: file String.cc, line 867. | |
6610 | Breakpoint 2 at 0xb344: file String.cc, line 875. | |
6611 | Breakpoint 3 at 0xafcc: file String.cc, line 846. | |
6612 | Multiple breakpoints were set. | |
6613 | Use the "delete" command to delete unwanted | |
6614 | breakpoints. | |
6615 | (@value{GDBP}) | |
6616 | @end group | |
6617 | @end smallexample | |
6618 | ||
6619 | @table @code | |
6620 | @kindex set multiple-symbols | |
6621 | @item set multiple-symbols @var{mode} | |
6622 | @cindex multiple-symbols menu | |
6623 | ||
6624 | This option allows you to adjust the debugger behavior when an expression | |
6625 | is ambiguous. | |
6626 | ||
6627 | By default, @var{mode} is set to @code{all}. If the command with which | |
6628 | the expression is used allows more than one choice, then @value{GDBN} | |
6629 | automatically selects all possible choices. For instance, inserting | |
6630 | a breakpoint on a function using an ambiguous name results in a breakpoint | |
6631 | inserted on each possible match. However, if a unique choice must be made, | |
6632 | then @value{GDBN} uses the menu to help you disambiguate the expression. | |
6633 | For instance, printing the address of an overloaded function will result | |
6634 | in the use of the menu. | |
6635 | ||
6636 | When @var{mode} is set to @code{ask}, the debugger always uses the menu | |
6637 | when an ambiguity is detected. | |
6638 | ||
6639 | Finally, when @var{mode} is set to @code{cancel}, the debugger reports | |
6640 | an error due to the ambiguity and the command is aborted. | |
6641 | ||
6642 | @kindex show multiple-symbols | |
6643 | @item show multiple-symbols | |
6644 | Show the current value of the @code{multiple-symbols} setting. | |
6645 | @end table | |
6646 | ||
6d2ebf8b | 6647 | @node Variables |
79a6e687 | 6648 | @section Program Variables |
c906108c SS |
6649 | |
6650 | The most common kind of expression to use is the name of a variable | |
6651 | in your program. | |
6652 | ||
6653 | Variables in expressions are understood in the selected stack frame | |
79a6e687 | 6654 | (@pxref{Selection, ,Selecting a Frame}); they must be either: |
c906108c SS |
6655 | |
6656 | @itemize @bullet | |
6657 | @item | |
6658 | global (or file-static) | |
6659 | @end itemize | |
6660 | ||
5d161b24 | 6661 | @noindent or |
c906108c SS |
6662 | |
6663 | @itemize @bullet | |
6664 | @item | |
6665 | visible according to the scope rules of the | |
6666 | programming language from the point of execution in that frame | |
5d161b24 | 6667 | @end itemize |
c906108c SS |
6668 | |
6669 | @noindent This means that in the function | |
6670 | ||
474c8240 | 6671 | @smallexample |
c906108c SS |
6672 | foo (a) |
6673 | int a; | |
6674 | @{ | |
6675 | bar (a); | |
6676 | @{ | |
6677 | int b = test (); | |
6678 | bar (b); | |
6679 | @} | |
6680 | @} | |
474c8240 | 6681 | @end smallexample |
c906108c SS |
6682 | |
6683 | @noindent | |
6684 | you can examine and use the variable @code{a} whenever your program is | |
6685 | executing within the function @code{foo}, but you can only use or | |
6686 | examine the variable @code{b} while your program is executing inside | |
6687 | the block where @code{b} is declared. | |
6688 | ||
6689 | @cindex variable name conflict | |
6690 | There is an exception: you can refer to a variable or function whose | |
6691 | scope is a single source file even if the current execution point is not | |
6692 | in this file. But it is possible to have more than one such variable or | |
6693 | function with the same name (in different source files). If that | |
6694 | happens, referring to that name has unpredictable effects. If you wish, | |
6695 | you can specify a static variable in a particular function or file, | |
15387254 | 6696 | using the colon-colon (@code{::}) notation: |
c906108c | 6697 | |
d4f3574e | 6698 | @cindex colon-colon, context for variables/functions |
12c27660 | 6699 | @ifnotinfo |
c906108c | 6700 | @c info cannot cope with a :: index entry, but why deprive hard copy readers? |
41afff9a | 6701 | @cindex @code{::}, context for variables/functions |
12c27660 | 6702 | @end ifnotinfo |
474c8240 | 6703 | @smallexample |
c906108c SS |
6704 | @var{file}::@var{variable} |
6705 | @var{function}::@var{variable} | |
474c8240 | 6706 | @end smallexample |
c906108c SS |
6707 | |
6708 | @noindent | |
6709 | Here @var{file} or @var{function} is the name of the context for the | |
6710 | static @var{variable}. In the case of file names, you can use quotes to | |
6711 | make sure @value{GDBN} parses the file name as a single word---for example, | |
6712 | to print a global value of @code{x} defined in @file{f2.c}: | |
6713 | ||
474c8240 | 6714 | @smallexample |
c906108c | 6715 | (@value{GDBP}) p 'f2.c'::x |
474c8240 | 6716 | @end smallexample |
c906108c | 6717 | |
b37052ae | 6718 | @cindex C@t{++} scope resolution |
c906108c | 6719 | This use of @samp{::} is very rarely in conflict with the very similar |
b37052ae | 6720 | use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++} |
c906108c SS |
6721 | scope resolution operator in @value{GDBN} expressions. |
6722 | @c FIXME: Um, so what happens in one of those rare cases where it's in | |
6723 | @c conflict?? --mew | |
c906108c SS |
6724 | |
6725 | @cindex wrong values | |
6726 | @cindex variable values, wrong | |
15387254 EZ |
6727 | @cindex function entry/exit, wrong values of variables |
6728 | @cindex optimized code, wrong values of variables | |
c906108c SS |
6729 | @quotation |
6730 | @emph{Warning:} Occasionally, a local variable may appear to have the | |
6731 | wrong value at certain points in a function---just after entry to a new | |
6732 | scope, and just before exit. | |
6733 | @end quotation | |
6734 | You may see this problem when you are stepping by machine instructions. | |
6735 | This is because, on most machines, it takes more than one instruction to | |
6736 | set up a stack frame (including local variable definitions); if you are | |
6737 | stepping by machine instructions, variables may appear to have the wrong | |
6738 | values until the stack frame is completely built. On exit, it usually | |
6739 | also takes more than one machine instruction to destroy a stack frame; | |
6740 | after you begin stepping through that group of instructions, local | |
6741 | variable definitions may be gone. | |
6742 | ||
6743 | This may also happen when the compiler does significant optimizations. | |
6744 | To be sure of always seeing accurate values, turn off all optimization | |
6745 | when compiling. | |
6746 | ||
d4f3574e SS |
6747 | @cindex ``No symbol "foo" in current context'' |
6748 | Another possible effect of compiler optimizations is to optimize | |
6749 | unused variables out of existence, or assign variables to registers (as | |
6750 | opposed to memory addresses). Depending on the support for such cases | |
6751 | offered by the debug info format used by the compiler, @value{GDBN} | |
6752 | might not be able to display values for such local variables. If that | |
6753 | happens, @value{GDBN} will print a message like this: | |
6754 | ||
474c8240 | 6755 | @smallexample |
d4f3574e | 6756 | No symbol "foo" in current context. |
474c8240 | 6757 | @end smallexample |
d4f3574e SS |
6758 | |
6759 | To solve such problems, either recompile without optimizations, or use a | |
6760 | different debug info format, if the compiler supports several such | |
15387254 | 6761 | formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler, |
0179ffac DC |
6762 | usually supports the @option{-gstabs+} option. @option{-gstabs+} |
6763 | produces debug info in a format that is superior to formats such as | |
6764 | COFF. You may be able to use DWARF 2 (@option{-gdwarf-2}), which is also | |
6765 | an effective form for debug info. @xref{Debugging Options,,Options | |
ce9341a1 BW |
6766 | for Debugging Your Program or GCC, gcc.info, Using the @sc{gnu} |
6767 | Compiler Collection (GCC)}. | |
79a6e687 | 6768 | @xref{C, ,C and C@t{++}}, for more information about debug info formats |
15387254 | 6769 | that are best suited to C@t{++} programs. |
d4f3574e | 6770 | |
ab1adacd EZ |
6771 | If you ask to print an object whose contents are unknown to |
6772 | @value{GDBN}, e.g., because its data type is not completely specified | |
6773 | by the debug information, @value{GDBN} will say @samp{<incomplete | |
6774 | type>}. @xref{Symbols, incomplete type}, for more about this. | |
6775 | ||
3a60f64e JK |
6776 | Strings are identified as arrays of @code{char} values without specified |
6777 | signedness. Arrays of either @code{signed char} or @code{unsigned char} get | |
6778 | printed as arrays of 1 byte sized integers. @code{-fsigned-char} or | |
6779 | @code{-funsigned-char} @value{NGCC} options have no effect as @value{GDBN} | |
6780 | defines literal string type @code{"char"} as @code{char} without a sign. | |
6781 | For program code | |
6782 | ||
6783 | @smallexample | |
6784 | char var0[] = "A"; | |
6785 | signed char var1[] = "A"; | |
6786 | @end smallexample | |
6787 | ||
6788 | You get during debugging | |
6789 | @smallexample | |
6790 | (gdb) print var0 | |
6791 | $1 = "A" | |
6792 | (gdb) print var1 | |
6793 | $2 = @{65 'A', 0 '\0'@} | |
6794 | @end smallexample | |
6795 | ||
6d2ebf8b | 6796 | @node Arrays |
79a6e687 | 6797 | @section Artificial Arrays |
c906108c SS |
6798 | |
6799 | @cindex artificial array | |
15387254 | 6800 | @cindex arrays |
41afff9a | 6801 | @kindex @@@r{, referencing memory as an array} |
c906108c SS |
6802 | It is often useful to print out several successive objects of the |
6803 | same type in memory; a section of an array, or an array of | |
6804 | dynamically determined size for which only a pointer exists in the | |
6805 | program. | |
6806 | ||
6807 | You can do this by referring to a contiguous span of memory as an | |
6808 | @dfn{artificial array}, using the binary operator @samp{@@}. The left | |
6809 | operand of @samp{@@} should be the first element of the desired array | |
6810 | and be an individual object. The right operand should be the desired length | |
6811 | of the array. The result is an array value whose elements are all of | |
6812 | the type of the left argument. The first element is actually the left | |
6813 | argument; the second element comes from bytes of memory immediately | |
6814 | following those that hold the first element, and so on. Here is an | |
6815 | example. If a program says | |
6816 | ||
474c8240 | 6817 | @smallexample |
c906108c | 6818 | int *array = (int *) malloc (len * sizeof (int)); |
474c8240 | 6819 | @end smallexample |
c906108c SS |
6820 | |
6821 | @noindent | |
6822 | you can print the contents of @code{array} with | |
6823 | ||
474c8240 | 6824 | @smallexample |
c906108c | 6825 | p *array@@len |
474c8240 | 6826 | @end smallexample |
c906108c SS |
6827 | |
6828 | The left operand of @samp{@@} must reside in memory. Array values made | |
6829 | with @samp{@@} in this way behave just like other arrays in terms of | |
6830 | subscripting, and are coerced to pointers when used in expressions. | |
6831 | Artificial arrays most often appear in expressions via the value history | |
79a6e687 | 6832 | (@pxref{Value History, ,Value History}), after printing one out. |
c906108c SS |
6833 | |
6834 | Another way to create an artificial array is to use a cast. | |
6835 | This re-interprets a value as if it were an array. | |
6836 | The value need not be in memory: | |
474c8240 | 6837 | @smallexample |
c906108c SS |
6838 | (@value{GDBP}) p/x (short[2])0x12345678 |
6839 | $1 = @{0x1234, 0x5678@} | |
474c8240 | 6840 | @end smallexample |
c906108c SS |
6841 | |
6842 | As a convenience, if you leave the array length out (as in | |
c3f6f71d | 6843 | @samp{(@var{type}[])@var{value}}) @value{GDBN} calculates the size to fill |
c906108c | 6844 | the value (as @samp{sizeof(@var{value})/sizeof(@var{type})}: |
474c8240 | 6845 | @smallexample |
c906108c SS |
6846 | (@value{GDBP}) p/x (short[])0x12345678 |
6847 | $2 = @{0x1234, 0x5678@} | |
474c8240 | 6848 | @end smallexample |
c906108c SS |
6849 | |
6850 | Sometimes the artificial array mechanism is not quite enough; in | |
6851 | moderately complex data structures, the elements of interest may not | |
6852 | actually be adjacent---for example, if you are interested in the values | |
6853 | of pointers in an array. One useful work-around in this situation is | |
6854 | to use a convenience variable (@pxref{Convenience Vars, ,Convenience | |
79a6e687 | 6855 | Variables}) as a counter in an expression that prints the first |
c906108c SS |
6856 | interesting value, and then repeat that expression via @key{RET}. For |
6857 | instance, suppose you have an array @code{dtab} of pointers to | |
6858 | structures, and you are interested in the values of a field @code{fv} | |
6859 | in each structure. Here is an example of what you might type: | |
6860 | ||
474c8240 | 6861 | @smallexample |
c906108c SS |
6862 | set $i = 0 |
6863 | p dtab[$i++]->fv | |
6864 | @key{RET} | |
6865 | @key{RET} | |
6866 | @dots{} | |
474c8240 | 6867 | @end smallexample |
c906108c | 6868 | |
6d2ebf8b | 6869 | @node Output Formats |
79a6e687 | 6870 | @section Output Formats |
c906108c SS |
6871 | |
6872 | @cindex formatted output | |
6873 | @cindex output formats | |
6874 | By default, @value{GDBN} prints a value according to its data type. Sometimes | |
6875 | this is not what you want. For example, you might want to print a number | |
6876 | in hex, or a pointer in decimal. Or you might want to view data in memory | |
6877 | at a certain address as a character string or as an instruction. To do | |
6878 | these things, specify an @dfn{output format} when you print a value. | |
6879 | ||
6880 | The simplest use of output formats is to say how to print a value | |
6881 | already computed. This is done by starting the arguments of the | |
6882 | @code{print} command with a slash and a format letter. The format | |
6883 | letters supported are: | |
6884 | ||
6885 | @table @code | |
6886 | @item x | |
6887 | Regard the bits of the value as an integer, and print the integer in | |
6888 | hexadecimal. | |
6889 | ||
6890 | @item d | |
6891 | Print as integer in signed decimal. | |
6892 | ||
6893 | @item u | |
6894 | Print as integer in unsigned decimal. | |
6895 | ||
6896 | @item o | |
6897 | Print as integer in octal. | |
6898 | ||
6899 | @item t | |
6900 | Print as integer in binary. The letter @samp{t} stands for ``two''. | |
6901 | @footnote{@samp{b} cannot be used because these format letters are also | |
6902 | used with the @code{x} command, where @samp{b} stands for ``byte''; | |
79a6e687 | 6903 | see @ref{Memory,,Examining Memory}.} |
c906108c SS |
6904 | |
6905 | @item a | |
6906 | @cindex unknown address, locating | |
3d67e040 | 6907 | @cindex locate address |
c906108c SS |
6908 | Print as an address, both absolute in hexadecimal and as an offset from |
6909 | the nearest preceding symbol. You can use this format used to discover | |
6910 | where (in what function) an unknown address is located: | |
6911 | ||
474c8240 | 6912 | @smallexample |
c906108c SS |
6913 | (@value{GDBP}) p/a 0x54320 |
6914 | $3 = 0x54320 <_initialize_vx+396> | |
474c8240 | 6915 | @end smallexample |
c906108c | 6916 | |
3d67e040 EZ |
6917 | @noindent |
6918 | The command @code{info symbol 0x54320} yields similar results. | |
6919 | @xref{Symbols, info symbol}. | |
6920 | ||
c906108c | 6921 | @item c |
51274035 EZ |
6922 | Regard as an integer and print it as a character constant. This |
6923 | prints both the numerical value and its character representation. The | |
6924 | character representation is replaced with the octal escape @samp{\nnn} | |
6925 | for characters outside the 7-bit @sc{ascii} range. | |
c906108c | 6926 | |
ea37ba09 DJ |
6927 | Without this format, @value{GDBN} displays @code{char}, |
6928 | @w{@code{unsigned char}}, and @w{@code{signed char}} data as character | |
6929 | constants. Single-byte members of vectors are displayed as integer | |
6930 | data. | |
6931 | ||
c906108c SS |
6932 | @item f |
6933 | Regard the bits of the value as a floating point number and print | |
6934 | using typical floating point syntax. | |
ea37ba09 DJ |
6935 | |
6936 | @item s | |
6937 | @cindex printing strings | |
6938 | @cindex printing byte arrays | |
6939 | Regard as a string, if possible. With this format, pointers to single-byte | |
6940 | data are displayed as null-terminated strings and arrays of single-byte data | |
6941 | are displayed as fixed-length strings. Other values are displayed in their | |
6942 | natural types. | |
6943 | ||
6944 | Without this format, @value{GDBN} displays pointers to and arrays of | |
6945 | @code{char}, @w{@code{unsigned char}}, and @w{@code{signed char}} as | |
6946 | strings. Single-byte members of a vector are displayed as an integer | |
6947 | array. | |
a6bac58e TT |
6948 | |
6949 | @item r | |
6950 | @cindex raw printing | |
6951 | Print using the @samp{raw} formatting. By default, @value{GDBN} will | |
6952 | use a type-specific pretty-printer. The @samp{r} format bypasses any | |
6953 | pretty-printer which might exist for the value's type. | |
c906108c SS |
6954 | @end table |
6955 | ||
6956 | For example, to print the program counter in hex (@pxref{Registers}), type | |
6957 | ||
474c8240 | 6958 | @smallexample |
c906108c | 6959 | p/x $pc |
474c8240 | 6960 | @end smallexample |
c906108c SS |
6961 | |
6962 | @noindent | |
6963 | Note that no space is required before the slash; this is because command | |
6964 | names in @value{GDBN} cannot contain a slash. | |
6965 | ||
6966 | To reprint the last value in the value history with a different format, | |
6967 | you can use the @code{print} command with just a format and no | |
6968 | expression. For example, @samp{p/x} reprints the last value in hex. | |
6969 | ||
6d2ebf8b | 6970 | @node Memory |
79a6e687 | 6971 | @section Examining Memory |
c906108c SS |
6972 | |
6973 | You can use the command @code{x} (for ``examine'') to examine memory in | |
6974 | any of several formats, independently of your program's data types. | |
6975 | ||
6976 | @cindex examining memory | |
6977 | @table @code | |
41afff9a | 6978 | @kindex x @r{(examine memory)} |
c906108c SS |
6979 | @item x/@var{nfu} @var{addr} |
6980 | @itemx x @var{addr} | |
6981 | @itemx x | |
6982 | Use the @code{x} command to examine memory. | |
6983 | @end table | |
6984 | ||
6985 | @var{n}, @var{f}, and @var{u} are all optional parameters that specify how | |
6986 | much memory to display and how to format it; @var{addr} is an | |
6987 | expression giving the address where you want to start displaying memory. | |
6988 | If you use defaults for @var{nfu}, you need not type the slash @samp{/}. | |
6989 | Several commands set convenient defaults for @var{addr}. | |
6990 | ||
6991 | @table @r | |
6992 | @item @var{n}, the repeat count | |
6993 | The repeat count is a decimal integer; the default is 1. It specifies | |
6994 | how much memory (counting by units @var{u}) to display. | |
6995 | @c This really is **decimal**; unaffected by 'set radix' as of GDB | |
6996 | @c 4.1.2. | |
6997 | ||
6998 | @item @var{f}, the display format | |
51274035 EZ |
6999 | The display format is one of the formats used by @code{print} |
7000 | (@samp{x}, @samp{d}, @samp{u}, @samp{o}, @samp{t}, @samp{a}, @samp{c}, | |
ea37ba09 DJ |
7001 | @samp{f}, @samp{s}), and in addition @samp{i} (for machine instructions). |
7002 | The default is @samp{x} (hexadecimal) initially. The default changes | |
7003 | each time you use either @code{x} or @code{print}. | |
c906108c SS |
7004 | |
7005 | @item @var{u}, the unit size | |
7006 | The unit size is any of | |
7007 | ||
7008 | @table @code | |
7009 | @item b | |
7010 | Bytes. | |
7011 | @item h | |
7012 | Halfwords (two bytes). | |
7013 | @item w | |
7014 | Words (four bytes). This is the initial default. | |
7015 | @item g | |
7016 | Giant words (eight bytes). | |
7017 | @end table | |
7018 | ||
7019 | Each time you specify a unit size with @code{x}, that size becomes the | |
7020 | default unit the next time you use @code{x}. (For the @samp{s} and | |
7021 | @samp{i} formats, the unit size is ignored and is normally not written.) | |
7022 | ||
7023 | @item @var{addr}, starting display address | |
7024 | @var{addr} is the address where you want @value{GDBN} to begin displaying | |
7025 | memory. The expression need not have a pointer value (though it may); | |
7026 | it is always interpreted as an integer address of a byte of memory. | |
7027 | @xref{Expressions, ,Expressions}, for more information on expressions. The default for | |
7028 | @var{addr} is usually just after the last address examined---but several | |
7029 | other commands also set the default address: @code{info breakpoints} (to | |
7030 | the address of the last breakpoint listed), @code{info line} (to the | |
7031 | starting address of a line), and @code{print} (if you use it to display | |
7032 | a value from memory). | |
7033 | @end table | |
7034 | ||
7035 | For example, @samp{x/3uh 0x54320} is a request to display three halfwords | |
7036 | (@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}), | |
7037 | starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four | |
7038 | words (@samp{w}) of memory above the stack pointer (here, @samp{$sp}; | |
d4f3574e | 7039 | @pxref{Registers, ,Registers}) in hexadecimal (@samp{x}). |
c906108c SS |
7040 | |
7041 | Since the letters indicating unit sizes are all distinct from the | |
7042 | letters specifying output formats, you do not have to remember whether | |
7043 | unit size or format comes first; either order works. The output | |
7044 | specifications @samp{4xw} and @samp{4wx} mean exactly the same thing. | |
7045 | (However, the count @var{n} must come first; @samp{wx4} does not work.) | |
7046 | ||
7047 | Even though the unit size @var{u} is ignored for the formats @samp{s} | |
7048 | and @samp{i}, you might still want to use a count @var{n}; for example, | |
7049 | @samp{3i} specifies that you want to see three machine instructions, | |
a4642986 MR |
7050 | including any operands. For convenience, especially when used with |
7051 | the @code{display} command, the @samp{i} format also prints branch delay | |
7052 | slot instructions, if any, beyond the count specified, which immediately | |
7053 | follow the last instruction that is within the count. The command | |
7054 | @code{disassemble} gives an alternative way of inspecting machine | |
7055 | instructions; see @ref{Machine Code,,Source and Machine Code}. | |
c906108c SS |
7056 | |
7057 | All the defaults for the arguments to @code{x} are designed to make it | |
7058 | easy to continue scanning memory with minimal specifications each time | |
7059 | you use @code{x}. For example, after you have inspected three machine | |
7060 | instructions with @samp{x/3i @var{addr}}, you can inspect the next seven | |
7061 | with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command, | |
7062 | the repeat count @var{n} is used again; the other arguments default as | |
7063 | for successive uses of @code{x}. | |
7064 | ||
7065 | @cindex @code{$_}, @code{$__}, and value history | |
7066 | The addresses and contents printed by the @code{x} command are not saved | |
7067 | in the value history because there is often too much of them and they | |
7068 | would get in the way. Instead, @value{GDBN} makes these values available for | |
7069 | subsequent use in expressions as values of the convenience variables | |
7070 | @code{$_} and @code{$__}. After an @code{x} command, the last address | |
7071 | examined is available for use in expressions in the convenience variable | |
7072 | @code{$_}. The contents of that address, as examined, are available in | |
7073 | the convenience variable @code{$__}. | |
7074 | ||
7075 | If the @code{x} command has a repeat count, the address and contents saved | |
7076 | are from the last memory unit printed; this is not the same as the last | |
7077 | address printed if several units were printed on the last line of output. | |
7078 | ||
09d4efe1 EZ |
7079 | @cindex remote memory comparison |
7080 | @cindex verify remote memory image | |
7081 | When you are debugging a program running on a remote target machine | |
ea35711c | 7082 | (@pxref{Remote Debugging}), you may wish to verify the program's image in the |
09d4efe1 EZ |
7083 | remote machine's memory against the executable file you downloaded to |
7084 | the target. The @code{compare-sections} command is provided for such | |
7085 | situations. | |
7086 | ||
7087 | @table @code | |
7088 | @kindex compare-sections | |
7089 | @item compare-sections @r{[}@var{section-name}@r{]} | |
7090 | Compare the data of a loadable section @var{section-name} in the | |
7091 | executable file of the program being debugged with the same section in | |
7092 | the remote machine's memory, and report any mismatches. With no | |
7093 | arguments, compares all loadable sections. This command's | |
7094 | availability depends on the target's support for the @code{"qCRC"} | |
7095 | remote request. | |
7096 | @end table | |
7097 | ||
6d2ebf8b | 7098 | @node Auto Display |
79a6e687 | 7099 | @section Automatic Display |
c906108c SS |
7100 | @cindex automatic display |
7101 | @cindex display of expressions | |
7102 | ||
7103 | If you find that you want to print the value of an expression frequently | |
7104 | (to see how it changes), you might want to add it to the @dfn{automatic | |
7105 | display list} so that @value{GDBN} prints its value each time your program stops. | |
7106 | Each expression added to the list is given a number to identify it; | |
7107 | to remove an expression from the list, you specify that number. | |
7108 | The automatic display looks like this: | |
7109 | ||
474c8240 | 7110 | @smallexample |
c906108c SS |
7111 | 2: foo = 38 |
7112 | 3: bar[5] = (struct hack *) 0x3804 | |
474c8240 | 7113 | @end smallexample |
c906108c SS |
7114 | |
7115 | @noindent | |
7116 | This display shows item numbers, expressions and their current values. As with | |
7117 | displays you request manually using @code{x} or @code{print}, you can | |
7118 | specify the output format you prefer; in fact, @code{display} decides | |
ea37ba09 DJ |
7119 | whether to use @code{print} or @code{x} depending your format |
7120 | specification---it uses @code{x} if you specify either the @samp{i} | |
7121 | or @samp{s} format, or a unit size; otherwise it uses @code{print}. | |
c906108c SS |
7122 | |
7123 | @table @code | |
7124 | @kindex display | |
d4f3574e SS |
7125 | @item display @var{expr} |
7126 | Add the expression @var{expr} to the list of expressions to display | |
c906108c SS |
7127 | each time your program stops. @xref{Expressions, ,Expressions}. |
7128 | ||
7129 | @code{display} does not repeat if you press @key{RET} again after using it. | |
7130 | ||
d4f3574e | 7131 | @item display/@var{fmt} @var{expr} |
c906108c | 7132 | For @var{fmt} specifying only a display format and not a size or |
d4f3574e | 7133 | count, add the expression @var{expr} to the auto-display list but |
c906108c | 7134 | arrange to display it each time in the specified format @var{fmt}. |
79a6e687 | 7135 | @xref{Output Formats,,Output Formats}. |
c906108c SS |
7136 | |
7137 | @item display/@var{fmt} @var{addr} | |
7138 | For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a | |
7139 | number of units, add the expression @var{addr} as a memory address to | |
7140 | be examined each time your program stops. Examining means in effect | |
79a6e687 | 7141 | doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining Memory}. |
c906108c SS |
7142 | @end table |
7143 | ||
7144 | For example, @samp{display/i $pc} can be helpful, to see the machine | |
7145 | instruction about to be executed each time execution stops (@samp{$pc} | |
d4f3574e | 7146 | is a common name for the program counter; @pxref{Registers, ,Registers}). |
c906108c SS |
7147 | |
7148 | @table @code | |
7149 | @kindex delete display | |
7150 | @kindex undisplay | |
7151 | @item undisplay @var{dnums}@dots{} | |
7152 | @itemx delete display @var{dnums}@dots{} | |
7153 | Remove item numbers @var{dnums} from the list of expressions to display. | |
7154 | ||
7155 | @code{undisplay} does not repeat if you press @key{RET} after using it. | |
7156 | (Otherwise you would just get the error @samp{No display number @dots{}}.) | |
7157 | ||
7158 | @kindex disable display | |
7159 | @item disable display @var{dnums}@dots{} | |
7160 | Disable the display of item numbers @var{dnums}. A disabled display | |
7161 | item is not printed automatically, but is not forgotten. It may be | |
7162 | enabled again later. | |
7163 | ||
7164 | @kindex enable display | |
7165 | @item enable display @var{dnums}@dots{} | |
7166 | Enable display of item numbers @var{dnums}. It becomes effective once | |
7167 | again in auto display of its expression, until you specify otherwise. | |
7168 | ||
7169 | @item display | |
7170 | Display the current values of the expressions on the list, just as is | |
7171 | done when your program stops. | |
7172 | ||
7173 | @kindex info display | |
7174 | @item info display | |
7175 | Print the list of expressions previously set up to display | |
7176 | automatically, each one with its item number, but without showing the | |
7177 | values. This includes disabled expressions, which are marked as such. | |
7178 | It also includes expressions which would not be displayed right now | |
7179 | because they refer to automatic variables not currently available. | |
7180 | @end table | |
7181 | ||
15387254 | 7182 | @cindex display disabled out of scope |
c906108c SS |
7183 | If a display expression refers to local variables, then it does not make |
7184 | sense outside the lexical context for which it was set up. Such an | |
7185 | expression is disabled when execution enters a context where one of its | |
7186 | variables is not defined. For example, if you give the command | |
7187 | @code{display last_char} while inside a function with an argument | |
7188 | @code{last_char}, @value{GDBN} displays this argument while your program | |
7189 | continues to stop inside that function. When it stops elsewhere---where | |
7190 | there is no variable @code{last_char}---the display is disabled | |
7191 | automatically. The next time your program stops where @code{last_char} | |
7192 | is meaningful, you can enable the display expression once again. | |
7193 | ||
6d2ebf8b | 7194 | @node Print Settings |
79a6e687 | 7195 | @section Print Settings |
c906108c SS |
7196 | |
7197 | @cindex format options | |
7198 | @cindex print settings | |
7199 | @value{GDBN} provides the following ways to control how arrays, structures, | |
7200 | and symbols are printed. | |
7201 | ||
7202 | @noindent | |
7203 | These settings are useful for debugging programs in any language: | |
7204 | ||
7205 | @table @code | |
4644b6e3 | 7206 | @kindex set print |
c906108c SS |
7207 | @item set print address |
7208 | @itemx set print address on | |
4644b6e3 | 7209 | @cindex print/don't print memory addresses |
c906108c SS |
7210 | @value{GDBN} prints memory addresses showing the location of stack |
7211 | traces, structure values, pointer values, breakpoints, and so forth, | |
7212 | even when it also displays the contents of those addresses. The default | |
7213 | is @code{on}. For example, this is what a stack frame display looks like with | |
7214 | @code{set print address on}: | |
7215 | ||
7216 | @smallexample | |
7217 | @group | |
7218 | (@value{GDBP}) f | |
7219 | #0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>") | |
7220 | at input.c:530 | |
7221 | 530 if (lquote != def_lquote) | |
7222 | @end group | |
7223 | @end smallexample | |
7224 | ||
7225 | @item set print address off | |
7226 | Do not print addresses when displaying their contents. For example, | |
7227 | this is the same stack frame displayed with @code{set print address off}: | |
7228 | ||
7229 | @smallexample | |
7230 | @group | |
7231 | (@value{GDBP}) set print addr off | |
7232 | (@value{GDBP}) f | |
7233 | #0 set_quotes (lq="<<", rq=">>") at input.c:530 | |
7234 | 530 if (lquote != def_lquote) | |
7235 | @end group | |
7236 | @end smallexample | |
7237 | ||
7238 | You can use @samp{set print address off} to eliminate all machine | |
7239 | dependent displays from the @value{GDBN} interface. For example, with | |
7240 | @code{print address off}, you should get the same text for backtraces on | |
7241 | all machines---whether or not they involve pointer arguments. | |
7242 | ||
4644b6e3 | 7243 | @kindex show print |
c906108c SS |
7244 | @item show print address |
7245 | Show whether or not addresses are to be printed. | |
7246 | @end table | |
7247 | ||
7248 | When @value{GDBN} prints a symbolic address, it normally prints the | |
7249 | closest earlier symbol plus an offset. If that symbol does not uniquely | |
7250 | identify the address (for example, it is a name whose scope is a single | |
7251 | source file), you may need to clarify. One way to do this is with | |
7252 | @code{info line}, for example @samp{info line *0x4537}. Alternately, | |
7253 | you can set @value{GDBN} to print the source file and line number when | |
7254 | it prints a symbolic address: | |
7255 | ||
7256 | @table @code | |
c906108c | 7257 | @item set print symbol-filename on |
9c16f35a EZ |
7258 | @cindex source file and line of a symbol |
7259 | @cindex symbol, source file and line | |
c906108c SS |
7260 | Tell @value{GDBN} to print the source file name and line number of a |
7261 | symbol in the symbolic form of an address. | |
7262 | ||
7263 | @item set print symbol-filename off | |
7264 | Do not print source file name and line number of a symbol. This is the | |
7265 | default. | |
7266 | ||
c906108c SS |
7267 | @item show print symbol-filename |
7268 | Show whether or not @value{GDBN} will print the source file name and | |
7269 | line number of a symbol in the symbolic form of an address. | |
7270 | @end table | |
7271 | ||
7272 | Another situation where it is helpful to show symbol filenames and line | |
7273 | numbers is when disassembling code; @value{GDBN} shows you the line | |
7274 | number and source file that corresponds to each instruction. | |
7275 | ||
7276 | Also, you may wish to see the symbolic form only if the address being | |
7277 | printed is reasonably close to the closest earlier symbol: | |
7278 | ||
7279 | @table @code | |
c906108c | 7280 | @item set print max-symbolic-offset @var{max-offset} |
4644b6e3 | 7281 | @cindex maximum value for offset of closest symbol |
c906108c SS |
7282 | Tell @value{GDBN} to only display the symbolic form of an address if the |
7283 | offset between the closest earlier symbol and the address is less than | |
5d161b24 | 7284 | @var{max-offset}. The default is 0, which tells @value{GDBN} |
c906108c SS |
7285 | to always print the symbolic form of an address if any symbol precedes it. |
7286 | ||
c906108c SS |
7287 | @item show print max-symbolic-offset |
7288 | Ask how large the maximum offset is that @value{GDBN} prints in a | |
7289 | symbolic address. | |
7290 | @end table | |
7291 | ||
7292 | @cindex wild pointer, interpreting | |
7293 | @cindex pointer, finding referent | |
7294 | If you have a pointer and you are not sure where it points, try | |
7295 | @samp{set print symbol-filename on}. Then you can determine the name | |
7296 | and source file location of the variable where it points, using | |
7297 | @samp{p/a @var{pointer}}. This interprets the address in symbolic form. | |
7298 | For example, here @value{GDBN} shows that a variable @code{ptt} points | |
7299 | at another variable @code{t}, defined in @file{hi2.c}: | |
7300 | ||
474c8240 | 7301 | @smallexample |
c906108c SS |
7302 | (@value{GDBP}) set print symbol-filename on |
7303 | (@value{GDBP}) p/a ptt | |
7304 | $4 = 0xe008 <t in hi2.c> | |
474c8240 | 7305 | @end smallexample |
c906108c SS |
7306 | |
7307 | @quotation | |
7308 | @emph{Warning:} For pointers that point to a local variable, @samp{p/a} | |
7309 | does not show the symbol name and filename of the referent, even with | |
7310 | the appropriate @code{set print} options turned on. | |
7311 | @end quotation | |
7312 | ||
7313 | Other settings control how different kinds of objects are printed: | |
7314 | ||
7315 | @table @code | |
c906108c SS |
7316 | @item set print array |
7317 | @itemx set print array on | |
4644b6e3 | 7318 | @cindex pretty print arrays |
c906108c SS |
7319 | Pretty print arrays. This format is more convenient to read, |
7320 | but uses more space. The default is off. | |
7321 | ||
7322 | @item set print array off | |
7323 | Return to compressed format for arrays. | |
7324 | ||
c906108c SS |
7325 | @item show print array |
7326 | Show whether compressed or pretty format is selected for displaying | |
7327 | arrays. | |
7328 | ||
3c9c013a JB |
7329 | @cindex print array indexes |
7330 | @item set print array-indexes | |
7331 | @itemx set print array-indexes on | |
7332 | Print the index of each element when displaying arrays. May be more | |
7333 | convenient to locate a given element in the array or quickly find the | |
7334 | index of a given element in that printed array. The default is off. | |
7335 | ||
7336 | @item set print array-indexes off | |
7337 | Stop printing element indexes when displaying arrays. | |
7338 | ||
7339 | @item show print array-indexes | |
7340 | Show whether the index of each element is printed when displaying | |
7341 | arrays. | |
7342 | ||
c906108c | 7343 | @item set print elements @var{number-of-elements} |
4644b6e3 | 7344 | @cindex number of array elements to print |
9c16f35a | 7345 | @cindex limit on number of printed array elements |
c906108c SS |
7346 | Set a limit on how many elements of an array @value{GDBN} will print. |
7347 | If @value{GDBN} is printing a large array, it stops printing after it has | |
7348 | printed the number of elements set by the @code{set print elements} command. | |
7349 | This limit also applies to the display of strings. | |
d4f3574e | 7350 | When @value{GDBN} starts, this limit is set to 200. |
c906108c SS |
7351 | Setting @var{number-of-elements} to zero means that the printing is unlimited. |
7352 | ||
c906108c SS |
7353 | @item show print elements |
7354 | Display the number of elements of a large array that @value{GDBN} will print. | |
7355 | If the number is 0, then the printing is unlimited. | |
7356 | ||
b4740add | 7357 | @item set print frame-arguments @var{value} |
a0381d3a | 7358 | @kindex set print frame-arguments |
b4740add JB |
7359 | @cindex printing frame argument values |
7360 | @cindex print all frame argument values | |
7361 | @cindex print frame argument values for scalars only | |
7362 | @cindex do not print frame argument values | |
7363 | This command allows to control how the values of arguments are printed | |
7364 | when the debugger prints a frame (@pxref{Frames}). The possible | |
7365 | values are: | |
7366 | ||
7367 | @table @code | |
7368 | @item all | |
4f5376b2 | 7369 | The values of all arguments are printed. |
b4740add JB |
7370 | |
7371 | @item scalars | |
7372 | Print the value of an argument only if it is a scalar. The value of more | |
7373 | complex arguments such as arrays, structures, unions, etc, is replaced | |
4f5376b2 JB |
7374 | by @code{@dots{}}. This is the default. Here is an example where |
7375 | only scalar arguments are shown: | |
b4740add JB |
7376 | |
7377 | @smallexample | |
7378 | #1 0x08048361 in call_me (i=3, s=@dots{}, ss=0xbf8d508c, u=@dots{}, e=green) | |
7379 | at frame-args.c:23 | |
7380 | @end smallexample | |
7381 | ||
7382 | @item none | |
7383 | None of the argument values are printed. Instead, the value of each argument | |
7384 | is replaced by @code{@dots{}}. In this case, the example above now becomes: | |
7385 | ||
7386 | @smallexample | |
7387 | #1 0x08048361 in call_me (i=@dots{}, s=@dots{}, ss=@dots{}, u=@dots{}, e=@dots{}) | |
7388 | at frame-args.c:23 | |
7389 | @end smallexample | |
7390 | @end table | |
7391 | ||
4f5376b2 JB |
7392 | By default, only scalar arguments are printed. This command can be used |
7393 | to configure the debugger to print the value of all arguments, regardless | |
7394 | of their type. However, it is often advantageous to not print the value | |
7395 | of more complex parameters. For instance, it reduces the amount of | |
7396 | information printed in each frame, making the backtrace more readable. | |
7397 | Also, it improves performance when displaying Ada frames, because | |
7398 | the computation of large arguments can sometimes be CPU-intensive, | |
7399 | especially in large applications. Setting @code{print frame-arguments} | |
7400 | to @code{scalars} (the default) or @code{none} avoids this computation, | |
7401 | thus speeding up the display of each Ada frame. | |
b4740add JB |
7402 | |
7403 | @item show print frame-arguments | |
7404 | Show how the value of arguments should be displayed when printing a frame. | |
7405 | ||
9c16f35a EZ |
7406 | @item set print repeats |
7407 | @cindex repeated array elements | |
7408 | Set the threshold for suppressing display of repeated array | |
d3e8051b | 7409 | elements. When the number of consecutive identical elements of an |
9c16f35a EZ |
7410 | array exceeds the threshold, @value{GDBN} prints the string |
7411 | @code{"<repeats @var{n} times>"}, where @var{n} is the number of | |
7412 | identical repetitions, instead of displaying the identical elements | |
7413 | themselves. Setting the threshold to zero will cause all elements to | |
7414 | be individually printed. The default threshold is 10. | |
7415 | ||
7416 | @item show print repeats | |
7417 | Display the current threshold for printing repeated identical | |
7418 | elements. | |
7419 | ||
c906108c | 7420 | @item set print null-stop |
4644b6e3 | 7421 | @cindex @sc{null} elements in arrays |
c906108c | 7422 | Cause @value{GDBN} to stop printing the characters of an array when the first |
d4f3574e | 7423 | @sc{null} is encountered. This is useful when large arrays actually |
c906108c | 7424 | contain only short strings. |
d4f3574e | 7425 | The default is off. |
c906108c | 7426 | |
9c16f35a EZ |
7427 | @item show print null-stop |
7428 | Show whether @value{GDBN} stops printing an array on the first | |
7429 | @sc{null} character. | |
7430 | ||
c906108c | 7431 | @item set print pretty on |
9c16f35a EZ |
7432 | @cindex print structures in indented form |
7433 | @cindex indentation in structure display | |
5d161b24 | 7434 | Cause @value{GDBN} to print structures in an indented format with one member |
c906108c SS |
7435 | per line, like this: |
7436 | ||
7437 | @smallexample | |
7438 | @group | |
7439 | $1 = @{ | |
7440 | next = 0x0, | |
7441 | flags = @{ | |
7442 | sweet = 1, | |
7443 | sour = 1 | |
7444 | @}, | |
7445 | meat = 0x54 "Pork" | |
7446 | @} | |
7447 | @end group | |
7448 | @end smallexample | |
7449 | ||
7450 | @item set print pretty off | |
7451 | Cause @value{GDBN} to print structures in a compact format, like this: | |
7452 | ||
7453 | @smallexample | |
7454 | @group | |
7455 | $1 = @{next = 0x0, flags = @{sweet = 1, sour = 1@}, \ | |
7456 | meat = 0x54 "Pork"@} | |
7457 | @end group | |
7458 | @end smallexample | |
7459 | ||
7460 | @noindent | |
7461 | This is the default format. | |
7462 | ||
c906108c SS |
7463 | @item show print pretty |
7464 | Show which format @value{GDBN} is using to print structures. | |
7465 | ||
c906108c | 7466 | @item set print sevenbit-strings on |
4644b6e3 EZ |
7467 | @cindex eight-bit characters in strings |
7468 | @cindex octal escapes in strings | |
c906108c SS |
7469 | Print using only seven-bit characters; if this option is set, |
7470 | @value{GDBN} displays any eight-bit characters (in strings or | |
7471 | character values) using the notation @code{\}@var{nnn}. This setting is | |
7472 | best if you are working in English (@sc{ascii}) and you use the | |
7473 | high-order bit of characters as a marker or ``meta'' bit. | |
7474 | ||
7475 | @item set print sevenbit-strings off | |
7476 | Print full eight-bit characters. This allows the use of more | |
7477 | international character sets, and is the default. | |
7478 | ||
c906108c SS |
7479 | @item show print sevenbit-strings |
7480 | Show whether or not @value{GDBN} is printing only seven-bit characters. | |
7481 | ||
c906108c | 7482 | @item set print union on |
4644b6e3 | 7483 | @cindex unions in structures, printing |
9c16f35a EZ |
7484 | Tell @value{GDBN} to print unions which are contained in structures |
7485 | and other unions. This is the default setting. | |
c906108c SS |
7486 | |
7487 | @item set print union off | |
9c16f35a EZ |
7488 | Tell @value{GDBN} not to print unions which are contained in |
7489 | structures and other unions. @value{GDBN} will print @code{"@{...@}"} | |
7490 | instead. | |
c906108c | 7491 | |
c906108c SS |
7492 | @item show print union |
7493 | Ask @value{GDBN} whether or not it will print unions which are contained in | |
9c16f35a | 7494 | structures and other unions. |
c906108c SS |
7495 | |
7496 | For example, given the declarations | |
7497 | ||
7498 | @smallexample | |
7499 | typedef enum @{Tree, Bug@} Species; | |
7500 | typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms; | |
5d161b24 | 7501 | typedef enum @{Caterpillar, Cocoon, Butterfly@} |
c906108c SS |
7502 | Bug_forms; |
7503 | ||
7504 | struct thing @{ | |
7505 | Species it; | |
7506 | union @{ | |
7507 | Tree_forms tree; | |
7508 | Bug_forms bug; | |
7509 | @} form; | |
7510 | @}; | |
7511 | ||
7512 | struct thing foo = @{Tree, @{Acorn@}@}; | |
7513 | @end smallexample | |
7514 | ||
7515 | @noindent | |
7516 | with @code{set print union on} in effect @samp{p foo} would print | |
7517 | ||
7518 | @smallexample | |
7519 | $1 = @{it = Tree, form = @{tree = Acorn, bug = Cocoon@}@} | |
7520 | @end smallexample | |
7521 | ||
7522 | @noindent | |
7523 | and with @code{set print union off} in effect it would print | |
7524 | ||
7525 | @smallexample | |
7526 | $1 = @{it = Tree, form = @{...@}@} | |
7527 | @end smallexample | |
9c16f35a EZ |
7528 | |
7529 | @noindent | |
7530 | @code{set print union} affects programs written in C-like languages | |
7531 | and in Pascal. | |
c906108c SS |
7532 | @end table |
7533 | ||
c906108c SS |
7534 | @need 1000 |
7535 | @noindent | |
b37052ae | 7536 | These settings are of interest when debugging C@t{++} programs: |
c906108c SS |
7537 | |
7538 | @table @code | |
4644b6e3 | 7539 | @cindex demangling C@t{++} names |
c906108c SS |
7540 | @item set print demangle |
7541 | @itemx set print demangle on | |
b37052ae | 7542 | Print C@t{++} names in their source form rather than in the encoded |
c906108c | 7543 | (``mangled'') form passed to the assembler and linker for type-safe |
d4f3574e | 7544 | linkage. The default is on. |
c906108c | 7545 | |
c906108c | 7546 | @item show print demangle |
b37052ae | 7547 | Show whether C@t{++} names are printed in mangled or demangled form. |
c906108c | 7548 | |
c906108c SS |
7549 | @item set print asm-demangle |
7550 | @itemx set print asm-demangle on | |
b37052ae | 7551 | Print C@t{++} names in their source form rather than their mangled form, even |
c906108c SS |
7552 | in assembler code printouts such as instruction disassemblies. |
7553 | The default is off. | |
7554 | ||
c906108c | 7555 | @item show print asm-demangle |
b37052ae | 7556 | Show whether C@t{++} names in assembly listings are printed in mangled |
c906108c SS |
7557 | or demangled form. |
7558 | ||
b37052ae EZ |
7559 | @cindex C@t{++} symbol decoding style |
7560 | @cindex symbol decoding style, C@t{++} | |
a8f24a35 | 7561 | @kindex set demangle-style |
c906108c SS |
7562 | @item set demangle-style @var{style} |
7563 | Choose among several encoding schemes used by different compilers to | |
b37052ae | 7564 | represent C@t{++} names. The choices for @var{style} are currently: |
c906108c SS |
7565 | |
7566 | @table @code | |
7567 | @item auto | |
7568 | Allow @value{GDBN} to choose a decoding style by inspecting your program. | |
7569 | ||
7570 | @item gnu | |
b37052ae | 7571 | Decode based on the @sc{gnu} C@t{++} compiler (@code{g++}) encoding algorithm. |
c906108c | 7572 | This is the default. |
c906108c SS |
7573 | |
7574 | @item hp | |
b37052ae | 7575 | Decode based on the HP ANSI C@t{++} (@code{aCC}) encoding algorithm. |
c906108c SS |
7576 | |
7577 | @item lucid | |
b37052ae | 7578 | Decode based on the Lucid C@t{++} compiler (@code{lcc}) encoding algorithm. |
c906108c SS |
7579 | |
7580 | @item arm | |
b37052ae | 7581 | Decode using the algorithm in the @cite{C@t{++} Annotated Reference Manual}. |
c906108c SS |
7582 | @strong{Warning:} this setting alone is not sufficient to allow |
7583 | debugging @code{cfront}-generated executables. @value{GDBN} would | |
7584 | require further enhancement to permit that. | |
7585 | ||
7586 | @end table | |
7587 | If you omit @var{style}, you will see a list of possible formats. | |
7588 | ||
c906108c | 7589 | @item show demangle-style |
b37052ae | 7590 | Display the encoding style currently in use for decoding C@t{++} symbols. |
c906108c | 7591 | |
c906108c SS |
7592 | @item set print object |
7593 | @itemx set print object on | |
4644b6e3 | 7594 | @cindex derived type of an object, printing |
9c16f35a | 7595 | @cindex display derived types |
c906108c SS |
7596 | When displaying a pointer to an object, identify the @emph{actual} |
7597 | (derived) type of the object rather than the @emph{declared} type, using | |
7598 | the virtual function table. | |
7599 | ||
7600 | @item set print object off | |
7601 | Display only the declared type of objects, without reference to the | |
7602 | virtual function table. This is the default setting. | |
7603 | ||
c906108c SS |
7604 | @item show print object |
7605 | Show whether actual, or declared, object types are displayed. | |
7606 | ||
c906108c SS |
7607 | @item set print static-members |
7608 | @itemx set print static-members on | |
4644b6e3 | 7609 | @cindex static members of C@t{++} objects |
b37052ae | 7610 | Print static members when displaying a C@t{++} object. The default is on. |
c906108c SS |
7611 | |
7612 | @item set print static-members off | |
b37052ae | 7613 | Do not print static members when displaying a C@t{++} object. |
c906108c | 7614 | |
c906108c | 7615 | @item show print static-members |
9c16f35a EZ |
7616 | Show whether C@t{++} static members are printed or not. |
7617 | ||
7618 | @item set print pascal_static-members | |
7619 | @itemx set print pascal_static-members on | |
d3e8051b EZ |
7620 | @cindex static members of Pascal objects |
7621 | @cindex Pascal objects, static members display | |
9c16f35a EZ |
7622 | Print static members when displaying a Pascal object. The default is on. |
7623 | ||
7624 | @item set print pascal_static-members off | |
7625 | Do not print static members when displaying a Pascal object. | |
7626 | ||
7627 | @item show print pascal_static-members | |
7628 | Show whether Pascal static members are printed or not. | |
c906108c SS |
7629 | |
7630 | @c These don't work with HP ANSI C++ yet. | |
c906108c SS |
7631 | @item set print vtbl |
7632 | @itemx set print vtbl on | |
4644b6e3 | 7633 | @cindex pretty print C@t{++} virtual function tables |
9c16f35a EZ |
7634 | @cindex virtual functions (C@t{++}) display |
7635 | @cindex VTBL display | |
b37052ae | 7636 | Pretty print C@t{++} virtual function tables. The default is off. |
c906108c | 7637 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 7638 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
7639 | |
7640 | @item set print vtbl off | |
b37052ae | 7641 | Do not pretty print C@t{++} virtual function tables. |
c906108c | 7642 | |
c906108c | 7643 | @item show print vtbl |
b37052ae | 7644 | Show whether C@t{++} virtual function tables are pretty printed, or not. |
c906108c | 7645 | @end table |
c906108c | 7646 | |
6d2ebf8b | 7647 | @node Value History |
79a6e687 | 7648 | @section Value History |
c906108c SS |
7649 | |
7650 | @cindex value history | |
9c16f35a | 7651 | @cindex history of values printed by @value{GDBN} |
5d161b24 DB |
7652 | Values printed by the @code{print} command are saved in the @value{GDBN} |
7653 | @dfn{value history}. This allows you to refer to them in other expressions. | |
7654 | Values are kept until the symbol table is re-read or discarded | |
7655 | (for example with the @code{file} or @code{symbol-file} commands). | |
7656 | When the symbol table changes, the value history is discarded, | |
7657 | since the values may contain pointers back to the types defined in the | |
c906108c SS |
7658 | symbol table. |
7659 | ||
7660 | @cindex @code{$} | |
7661 | @cindex @code{$$} | |
7662 | @cindex history number | |
7663 | The values printed are given @dfn{history numbers} by which you can | |
7664 | refer to them. These are successive integers starting with one. | |
7665 | @code{print} shows you the history number assigned to a value by | |
7666 | printing @samp{$@var{num} = } before the value; here @var{num} is the | |
7667 | history number. | |
7668 | ||
7669 | To refer to any previous value, use @samp{$} followed by the value's | |
7670 | history number. The way @code{print} labels its output is designed to | |
7671 | remind you of this. Just @code{$} refers to the most recent value in | |
7672 | the history, and @code{$$} refers to the value before that. | |
7673 | @code{$$@var{n}} refers to the @var{n}th value from the end; @code{$$2} | |
7674 | is the value just prior to @code{$$}, @code{$$1} is equivalent to | |
7675 | @code{$$}, and @code{$$0} is equivalent to @code{$}. | |
7676 | ||
7677 | For example, suppose you have just printed a pointer to a structure and | |
7678 | want to see the contents of the structure. It suffices to type | |
7679 | ||
474c8240 | 7680 | @smallexample |
c906108c | 7681 | p *$ |
474c8240 | 7682 | @end smallexample |
c906108c SS |
7683 | |
7684 | If you have a chain of structures where the component @code{next} points | |
7685 | to the next one, you can print the contents of the next one with this: | |
7686 | ||
474c8240 | 7687 | @smallexample |
c906108c | 7688 | p *$.next |
474c8240 | 7689 | @end smallexample |
c906108c SS |
7690 | |
7691 | @noindent | |
7692 | You can print successive links in the chain by repeating this | |
7693 | command---which you can do by just typing @key{RET}. | |
7694 | ||
7695 | Note that the history records values, not expressions. If the value of | |
7696 | @code{x} is 4 and you type these commands: | |
7697 | ||
474c8240 | 7698 | @smallexample |
c906108c SS |
7699 | print x |
7700 | set x=5 | |
474c8240 | 7701 | @end smallexample |
c906108c SS |
7702 | |
7703 | @noindent | |
7704 | then the value recorded in the value history by the @code{print} command | |
7705 | remains 4 even though the value of @code{x} has changed. | |
7706 | ||
7707 | @table @code | |
7708 | @kindex show values | |
7709 | @item show values | |
7710 | Print the last ten values in the value history, with their item numbers. | |
7711 | This is like @samp{p@ $$9} repeated ten times, except that @code{show | |
7712 | values} does not change the history. | |
7713 | ||
7714 | @item show values @var{n} | |
7715 | Print ten history values centered on history item number @var{n}. | |
7716 | ||
7717 | @item show values + | |
7718 | Print ten history values just after the values last printed. If no more | |
7719 | values are available, @code{show values +} produces no display. | |
7720 | @end table | |
7721 | ||
7722 | Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the | |
7723 | same effect as @samp{show values +}. | |
7724 | ||
6d2ebf8b | 7725 | @node Convenience Vars |
79a6e687 | 7726 | @section Convenience Variables |
c906108c SS |
7727 | |
7728 | @cindex convenience variables | |
9c16f35a | 7729 | @cindex user-defined variables |
c906108c SS |
7730 | @value{GDBN} provides @dfn{convenience variables} that you can use within |
7731 | @value{GDBN} to hold on to a value and refer to it later. These variables | |
7732 | exist entirely within @value{GDBN}; they are not part of your program, and | |
7733 | setting a convenience variable has no direct effect on further execution | |
7734 | of your program. That is why you can use them freely. | |
7735 | ||
7736 | Convenience variables are prefixed with @samp{$}. Any name preceded by | |
7737 | @samp{$} can be used for a convenience variable, unless it is one of | |
d4f3574e | 7738 | the predefined machine-specific register names (@pxref{Registers, ,Registers}). |
c906108c | 7739 | (Value history references, in contrast, are @emph{numbers} preceded |
79a6e687 | 7740 | by @samp{$}. @xref{Value History, ,Value History}.) |
c906108c SS |
7741 | |
7742 | You can save a value in a convenience variable with an assignment | |
7743 | expression, just as you would set a variable in your program. | |
7744 | For example: | |
7745 | ||
474c8240 | 7746 | @smallexample |
c906108c | 7747 | set $foo = *object_ptr |
474c8240 | 7748 | @end smallexample |
c906108c SS |
7749 | |
7750 | @noindent | |
7751 | would save in @code{$foo} the value contained in the object pointed to by | |
7752 | @code{object_ptr}. | |
7753 | ||
7754 | Using a convenience variable for the first time creates it, but its | |
7755 | value is @code{void} until you assign a new value. You can alter the | |
7756 | value with another assignment at any time. | |
7757 | ||
7758 | Convenience variables have no fixed types. You can assign a convenience | |
7759 | variable any type of value, including structures and arrays, even if | |
7760 | that variable already has a value of a different type. The convenience | |
7761 | variable, when used as an expression, has the type of its current value. | |
7762 | ||
7763 | @table @code | |
7764 | @kindex show convenience | |
9c16f35a | 7765 | @cindex show all user variables |
c906108c SS |
7766 | @item show convenience |
7767 | Print a list of convenience variables used so far, and their values. | |
d4f3574e | 7768 | Abbreviated @code{show conv}. |
53e5f3cf AS |
7769 | |
7770 | @kindex init-if-undefined | |
7771 | @cindex convenience variables, initializing | |
7772 | @item init-if-undefined $@var{variable} = @var{expression} | |
7773 | Set a convenience variable if it has not already been set. This is useful | |
7774 | for user-defined commands that keep some state. It is similar, in concept, | |
7775 | to using local static variables with initializers in C (except that | |
7776 | convenience variables are global). It can also be used to allow users to | |
7777 | override default values used in a command script. | |
7778 | ||
7779 | If the variable is already defined then the expression is not evaluated so | |
7780 | any side-effects do not occur. | |
c906108c SS |
7781 | @end table |
7782 | ||
7783 | One of the ways to use a convenience variable is as a counter to be | |
7784 | incremented or a pointer to be advanced. For example, to print | |
7785 | a field from successive elements of an array of structures: | |
7786 | ||
474c8240 | 7787 | @smallexample |
c906108c SS |
7788 | set $i = 0 |
7789 | print bar[$i++]->contents | |
474c8240 | 7790 | @end smallexample |
c906108c | 7791 | |
d4f3574e SS |
7792 | @noindent |
7793 | Repeat that command by typing @key{RET}. | |
c906108c SS |
7794 | |
7795 | Some convenience variables are created automatically by @value{GDBN} and given | |
7796 | values likely to be useful. | |
7797 | ||
7798 | @table @code | |
41afff9a | 7799 | @vindex $_@r{, convenience variable} |
c906108c SS |
7800 | @item $_ |
7801 | The variable @code{$_} is automatically set by the @code{x} command to | |
79a6e687 | 7802 | the last address examined (@pxref{Memory, ,Examining Memory}). Other |
c906108c SS |
7803 | commands which provide a default address for @code{x} to examine also |
7804 | set @code{$_} to that address; these commands include @code{info line} | |
7805 | and @code{info breakpoint}. The type of @code{$_} is @code{void *} | |
7806 | except when set by the @code{x} command, in which case it is a pointer | |
7807 | to the type of @code{$__}. | |
7808 | ||
41afff9a | 7809 | @vindex $__@r{, convenience variable} |
c906108c SS |
7810 | @item $__ |
7811 | The variable @code{$__} is automatically set by the @code{x} command | |
7812 | to the value found in the last address examined. Its type is chosen | |
7813 | to match the format in which the data was printed. | |
7814 | ||
7815 | @item $_exitcode | |
41afff9a | 7816 | @vindex $_exitcode@r{, convenience variable} |
c906108c SS |
7817 | The variable @code{$_exitcode} is automatically set to the exit code when |
7818 | the program being debugged terminates. | |
4aa995e1 PA |
7819 | |
7820 | @item $_siginfo | |
7821 | @vindex $_siginfo@r{, convenience variable} | |
ec7e75e7 PP |
7822 | The variable @code{$_siginfo} contains extra signal information |
7823 | (@pxref{extra signal information}). Note that @code{$_siginfo} | |
7824 | could be empty, if the application has not yet received any signals. | |
7825 | For example, it will be empty before you execute the @code{run} command. | |
c906108c SS |
7826 | @end table |
7827 | ||
53a5351d JM |
7828 | On HP-UX systems, if you refer to a function or variable name that |
7829 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
7830 | name first, before it searches for a convenience variable. | |
c906108c | 7831 | |
bc3b79fd TJB |
7832 | @cindex convenience functions |
7833 | @value{GDBN} also supplies some @dfn{convenience functions}. These | |
7834 | have a syntax similar to convenience variables. A convenience | |
7835 | function can be used in an expression just like an ordinary function; | |
7836 | however, a convenience function is implemented internally to | |
7837 | @value{GDBN}. | |
7838 | ||
7839 | @table @code | |
7840 | @item help function | |
7841 | @kindex help function | |
7842 | @cindex show all convenience functions | |
7843 | Print a list of all convenience functions. | |
7844 | @end table | |
7845 | ||
6d2ebf8b | 7846 | @node Registers |
c906108c SS |
7847 | @section Registers |
7848 | ||
7849 | @cindex registers | |
7850 | You can refer to machine register contents, in expressions, as variables | |
7851 | with names starting with @samp{$}. The names of registers are different | |
7852 | for each machine; use @code{info registers} to see the names used on | |
7853 | your machine. | |
7854 | ||
7855 | @table @code | |
7856 | @kindex info registers | |
7857 | @item info registers | |
7858 | Print the names and values of all registers except floating-point | |
c85508ee | 7859 | and vector registers (in the selected stack frame). |
c906108c SS |
7860 | |
7861 | @kindex info all-registers | |
7862 | @cindex floating point registers | |
7863 | @item info all-registers | |
7864 | Print the names and values of all registers, including floating-point | |
c85508ee | 7865 | and vector registers (in the selected stack frame). |
c906108c SS |
7866 | |
7867 | @item info registers @var{regname} @dots{} | |
7868 | Print the @dfn{relativized} value of each specified register @var{regname}. | |
5d161b24 DB |
7869 | As discussed in detail below, register values are normally relative to |
7870 | the selected stack frame. @var{regname} may be any register name valid on | |
c906108c SS |
7871 | the machine you are using, with or without the initial @samp{$}. |
7872 | @end table | |
7873 | ||
e09f16f9 EZ |
7874 | @cindex stack pointer register |
7875 | @cindex program counter register | |
7876 | @cindex process status register | |
7877 | @cindex frame pointer register | |
7878 | @cindex standard registers | |
c906108c SS |
7879 | @value{GDBN} has four ``standard'' register names that are available (in |
7880 | expressions) on most machines---whenever they do not conflict with an | |
7881 | architecture's canonical mnemonics for registers. The register names | |
7882 | @code{$pc} and @code{$sp} are used for the program counter register and | |
7883 | the stack pointer. @code{$fp} is used for a register that contains a | |
7884 | pointer to the current stack frame, and @code{$ps} is used for a | |
7885 | register that contains the processor status. For example, | |
7886 | you could print the program counter in hex with | |
7887 | ||
474c8240 | 7888 | @smallexample |
c906108c | 7889 | p/x $pc |
474c8240 | 7890 | @end smallexample |
c906108c SS |
7891 | |
7892 | @noindent | |
7893 | or print the instruction to be executed next with | |
7894 | ||
474c8240 | 7895 | @smallexample |
c906108c | 7896 | x/i $pc |
474c8240 | 7897 | @end smallexample |
c906108c SS |
7898 | |
7899 | @noindent | |
7900 | or add four to the stack pointer@footnote{This is a way of removing | |
7901 | one word from the stack, on machines where stacks grow downward in | |
7902 | memory (most machines, nowadays). This assumes that the innermost | |
7903 | stack frame is selected; setting @code{$sp} is not allowed when other | |
7904 | stack frames are selected. To pop entire frames off the stack, | |
7905 | regardless of machine architecture, use @code{return}; | |
79a6e687 | 7906 | see @ref{Returning, ,Returning from a Function}.} with |
c906108c | 7907 | |
474c8240 | 7908 | @smallexample |
c906108c | 7909 | set $sp += 4 |
474c8240 | 7910 | @end smallexample |
c906108c SS |
7911 | |
7912 | Whenever possible, these four standard register names are available on | |
7913 | your machine even though the machine has different canonical mnemonics, | |
7914 | so long as there is no conflict. The @code{info registers} command | |
7915 | shows the canonical names. For example, on the SPARC, @code{info | |
7916 | registers} displays the processor status register as @code{$psr} but you | |
d4f3574e SS |
7917 | can also refer to it as @code{$ps}; and on x86-based machines @code{$ps} |
7918 | is an alias for the @sc{eflags} register. | |
c906108c SS |
7919 | |
7920 | @value{GDBN} always considers the contents of an ordinary register as an | |
7921 | integer when the register is examined in this way. Some machines have | |
7922 | special registers which can hold nothing but floating point; these | |
7923 | registers are considered to have floating point values. There is no way | |
7924 | to refer to the contents of an ordinary register as floating point value | |
7925 | (although you can @emph{print} it as a floating point value with | |
7926 | @samp{print/f $@var{regname}}). | |
7927 | ||
7928 | Some registers have distinct ``raw'' and ``virtual'' data formats. This | |
7929 | means that the data format in which the register contents are saved by | |
7930 | the operating system is not the same one that your program normally | |
7931 | sees. For example, the registers of the 68881 floating point | |
7932 | coprocessor are always saved in ``extended'' (raw) format, but all C | |
7933 | programs expect to work with ``double'' (virtual) format. In such | |
5d161b24 | 7934 | cases, @value{GDBN} normally works with the virtual format only (the format |
c906108c SS |
7935 | that makes sense for your program), but the @code{info registers} command |
7936 | prints the data in both formats. | |
7937 | ||
36b80e65 EZ |
7938 | @cindex SSE registers (x86) |
7939 | @cindex MMX registers (x86) | |
7940 | Some machines have special registers whose contents can be interpreted | |
7941 | in several different ways. For example, modern x86-based machines | |
7942 | have SSE and MMX registers that can hold several values packed | |
7943 | together in several different formats. @value{GDBN} refers to such | |
7944 | registers in @code{struct} notation: | |
7945 | ||
7946 | @smallexample | |
7947 | (@value{GDBP}) print $xmm1 | |
7948 | $1 = @{ | |
7949 | v4_float = @{0, 3.43859137e-038, 1.54142831e-044, 1.821688e-044@}, | |
7950 | v2_double = @{9.92129282474342e-303, 2.7585945287983262e-313@}, | |
7951 | v16_int8 = "\000\000\000\000\3706;\001\v\000\000\000\r\000\000", | |
7952 | v8_int16 = @{0, 0, 14072, 315, 11, 0, 13, 0@}, | |
7953 | v4_int32 = @{0, 20657912, 11, 13@}, | |
7954 | v2_int64 = @{88725056443645952, 55834574859@}, | |
7955 | uint128 = 0x0000000d0000000b013b36f800000000 | |
7956 | @} | |
7957 | @end smallexample | |
7958 | ||
7959 | @noindent | |
7960 | To set values of such registers, you need to tell @value{GDBN} which | |
7961 | view of the register you wish to change, as if you were assigning | |
7962 | value to a @code{struct} member: | |
7963 | ||
7964 | @smallexample | |
7965 | (@value{GDBP}) set $xmm1.uint128 = 0x000000000000000000000000FFFFFFFF | |
7966 | @end smallexample | |
7967 | ||
c906108c | 7968 | Normally, register values are relative to the selected stack frame |
79a6e687 | 7969 | (@pxref{Selection, ,Selecting a Frame}). This means that you get the |
c906108c SS |
7970 | value that the register would contain if all stack frames farther in |
7971 | were exited and their saved registers restored. In order to see the | |
7972 | true contents of hardware registers, you must select the innermost | |
7973 | frame (with @samp{frame 0}). | |
7974 | ||
7975 | However, @value{GDBN} must deduce where registers are saved, from the machine | |
7976 | code generated by your compiler. If some registers are not saved, or if | |
7977 | @value{GDBN} is unable to locate the saved registers, the selected stack | |
7978 | frame makes no difference. | |
7979 | ||
6d2ebf8b | 7980 | @node Floating Point Hardware |
79a6e687 | 7981 | @section Floating Point Hardware |
c906108c SS |
7982 | @cindex floating point |
7983 | ||
7984 | Depending on the configuration, @value{GDBN} may be able to give | |
7985 | you more information about the status of the floating point hardware. | |
7986 | ||
7987 | @table @code | |
7988 | @kindex info float | |
7989 | @item info float | |
7990 | Display hardware-dependent information about the floating | |
7991 | point unit. The exact contents and layout vary depending on the | |
7992 | floating point chip. Currently, @samp{info float} is supported on | |
7993 | the ARM and x86 machines. | |
7994 | @end table | |
c906108c | 7995 | |
e76f1f2e AC |
7996 | @node Vector Unit |
7997 | @section Vector Unit | |
7998 | @cindex vector unit | |
7999 | ||
8000 | Depending on the configuration, @value{GDBN} may be able to give you | |
8001 | more information about the status of the vector unit. | |
8002 | ||
8003 | @table @code | |
8004 | @kindex info vector | |
8005 | @item info vector | |
8006 | Display information about the vector unit. The exact contents and | |
8007 | layout vary depending on the hardware. | |
8008 | @end table | |
8009 | ||
721c2651 | 8010 | @node OS Information |
79a6e687 | 8011 | @section Operating System Auxiliary Information |
721c2651 EZ |
8012 | @cindex OS information |
8013 | ||
8014 | @value{GDBN} provides interfaces to useful OS facilities that can help | |
8015 | you debug your program. | |
8016 | ||
8017 | @cindex @code{ptrace} system call | |
8018 | @cindex @code{struct user} contents | |
8019 | When @value{GDBN} runs on a @dfn{Posix system} (such as GNU or Unix | |
8020 | machines), it interfaces with the inferior via the @code{ptrace} | |
8021 | system call. The operating system creates a special sata structure, | |
8022 | called @code{struct user}, for this interface. You can use the | |
8023 | command @code{info udot} to display the contents of this data | |
8024 | structure. | |
8025 | ||
8026 | @table @code | |
8027 | @item info udot | |
8028 | @kindex info udot | |
8029 | Display the contents of the @code{struct user} maintained by the OS | |
8030 | kernel for the program being debugged. @value{GDBN} displays the | |
8031 | contents of @code{struct user} as a list of hex numbers, similar to | |
8032 | the @code{examine} command. | |
8033 | @end table | |
8034 | ||
b383017d RM |
8035 | @cindex auxiliary vector |
8036 | @cindex vector, auxiliary | |
b383017d RM |
8037 | Some operating systems supply an @dfn{auxiliary vector} to programs at |
8038 | startup. This is akin to the arguments and environment that you | |
8039 | specify for a program, but contains a system-dependent variety of | |
8040 | binary values that tell system libraries important details about the | |
8041 | hardware, operating system, and process. Each value's purpose is | |
8042 | identified by an integer tag; the meanings are well-known but system-specific. | |
8043 | Depending on the configuration and operating system facilities, | |
9c16f35a EZ |
8044 | @value{GDBN} may be able to show you this information. For remote |
8045 | targets, this functionality may further depend on the remote stub's | |
427c3a89 DJ |
8046 | support of the @samp{qXfer:auxv:read} packet, see |
8047 | @ref{qXfer auxiliary vector read}. | |
b383017d RM |
8048 | |
8049 | @table @code | |
8050 | @kindex info auxv | |
8051 | @item info auxv | |
8052 | Display the auxiliary vector of the inferior, which can be either a | |
e4937fc1 | 8053 | live process or a core dump file. @value{GDBN} prints each tag value |
b383017d RM |
8054 | numerically, and also shows names and text descriptions for recognized |
8055 | tags. Some values in the vector are numbers, some bit masks, and some | |
e4937fc1 | 8056 | pointers to strings or other data. @value{GDBN} displays each value in the |
b383017d RM |
8057 | most appropriate form for a recognized tag, and in hexadecimal for |
8058 | an unrecognized tag. | |
8059 | @end table | |
8060 | ||
07e059b5 VP |
8061 | On some targets, @value{GDBN} can access operating-system-specific information |
8062 | and display it to user, without interpretation. For remote targets, | |
8063 | this functionality depends on the remote stub's support of the | |
8064 | @samp{qXfer:osdata:read} packet, see @ref{qXfer osdata read}. | |
8065 | ||
8066 | @table @code | |
8067 | @kindex info os processes | |
8068 | @item info os processes | |
8069 | Display the list of processes on the target. For each process, | |
8070 | @value{GDBN} prints the process identifier, the name of the user, and | |
8071 | the command corresponding to the process. | |
8072 | @end table | |
721c2651 | 8073 | |
29e57380 | 8074 | @node Memory Region Attributes |
79a6e687 | 8075 | @section Memory Region Attributes |
29e57380 C |
8076 | @cindex memory region attributes |
8077 | ||
b383017d | 8078 | @dfn{Memory region attributes} allow you to describe special handling |
fd79ecee DJ |
8079 | required by regions of your target's memory. @value{GDBN} uses |
8080 | attributes to determine whether to allow certain types of memory | |
8081 | accesses; whether to use specific width accesses; and whether to cache | |
8082 | target memory. By default the description of memory regions is | |
8083 | fetched from the target (if the current target supports this), but the | |
8084 | user can override the fetched regions. | |
29e57380 C |
8085 | |
8086 | Defined memory regions can be individually enabled and disabled. When a | |
8087 | memory region is disabled, @value{GDBN} uses the default attributes when | |
8088 | accessing memory in that region. Similarly, if no memory regions have | |
8089 | been defined, @value{GDBN} uses the default attributes when accessing | |
8090 | all memory. | |
8091 | ||
b383017d | 8092 | When a memory region is defined, it is given a number to identify it; |
29e57380 C |
8093 | to enable, disable, or remove a memory region, you specify that number. |
8094 | ||
8095 | @table @code | |
8096 | @kindex mem | |
bfac230e | 8097 | @item mem @var{lower} @var{upper} @var{attributes}@dots{} |
09d4efe1 EZ |
8098 | Define a memory region bounded by @var{lower} and @var{upper} with |
8099 | attributes @var{attributes}@dots{}, and add it to the list of regions | |
8100 | monitored by @value{GDBN}. Note that @var{upper} == 0 is a special | |
d3e8051b | 8101 | case: it is treated as the target's maximum memory address. |
bfac230e | 8102 | (0xffff on 16 bit targets, 0xffffffff on 32 bit targets, etc.) |
29e57380 | 8103 | |
fd79ecee DJ |
8104 | @item mem auto |
8105 | Discard any user changes to the memory regions and use target-supplied | |
8106 | regions, if available, or no regions if the target does not support. | |
8107 | ||
29e57380 C |
8108 | @kindex delete mem |
8109 | @item delete mem @var{nums}@dots{} | |
09d4efe1 EZ |
8110 | Remove memory regions @var{nums}@dots{} from the list of regions |
8111 | monitored by @value{GDBN}. | |
29e57380 C |
8112 | |
8113 | @kindex disable mem | |
8114 | @item disable mem @var{nums}@dots{} | |
09d4efe1 | 8115 | Disable monitoring of memory regions @var{nums}@dots{}. |
b383017d | 8116 | A disabled memory region is not forgotten. |
29e57380 C |
8117 | It may be enabled again later. |
8118 | ||
8119 | @kindex enable mem | |
8120 | @item enable mem @var{nums}@dots{} | |
09d4efe1 | 8121 | Enable monitoring of memory regions @var{nums}@dots{}. |
29e57380 C |
8122 | |
8123 | @kindex info mem | |
8124 | @item info mem | |
8125 | Print a table of all defined memory regions, with the following columns | |
09d4efe1 | 8126 | for each region: |
29e57380 C |
8127 | |
8128 | @table @emph | |
8129 | @item Memory Region Number | |
8130 | @item Enabled or Disabled. | |
b383017d | 8131 | Enabled memory regions are marked with @samp{y}. |
29e57380 C |
8132 | Disabled memory regions are marked with @samp{n}. |
8133 | ||
8134 | @item Lo Address | |
8135 | The address defining the inclusive lower bound of the memory region. | |
8136 | ||
8137 | @item Hi Address | |
8138 | The address defining the exclusive upper bound of the memory region. | |
8139 | ||
8140 | @item Attributes | |
8141 | The list of attributes set for this memory region. | |
8142 | @end table | |
8143 | @end table | |
8144 | ||
8145 | ||
8146 | @subsection Attributes | |
8147 | ||
b383017d | 8148 | @subsubsection Memory Access Mode |
29e57380 C |
8149 | The access mode attributes set whether @value{GDBN} may make read or |
8150 | write accesses to a memory region. | |
8151 | ||
8152 | While these attributes prevent @value{GDBN} from performing invalid | |
8153 | memory accesses, they do nothing to prevent the target system, I/O DMA, | |
359df76b | 8154 | etc.@: from accessing memory. |
29e57380 C |
8155 | |
8156 | @table @code | |
8157 | @item ro | |
8158 | Memory is read only. | |
8159 | @item wo | |
8160 | Memory is write only. | |
8161 | @item rw | |
6ca652b0 | 8162 | Memory is read/write. This is the default. |
29e57380 C |
8163 | @end table |
8164 | ||
8165 | @subsubsection Memory Access Size | |
d3e8051b | 8166 | The access size attribute tells @value{GDBN} to use specific sized |
29e57380 C |
8167 | accesses in the memory region. Often memory mapped device registers |
8168 | require specific sized accesses. If no access size attribute is | |
8169 | specified, @value{GDBN} may use accesses of any size. | |
8170 | ||
8171 | @table @code | |
8172 | @item 8 | |
8173 | Use 8 bit memory accesses. | |
8174 | @item 16 | |
8175 | Use 16 bit memory accesses. | |
8176 | @item 32 | |
8177 | Use 32 bit memory accesses. | |
8178 | @item 64 | |
8179 | Use 64 bit memory accesses. | |
8180 | @end table | |
8181 | ||
8182 | @c @subsubsection Hardware/Software Breakpoints | |
8183 | @c The hardware/software breakpoint attributes set whether @value{GDBN} | |
8184 | @c will use hardware or software breakpoints for the internal breakpoints | |
8185 | @c used by the step, next, finish, until, etc. commands. | |
8186 | @c | |
8187 | @c @table @code | |
8188 | @c @item hwbreak | |
b383017d | 8189 | @c Always use hardware breakpoints |
29e57380 C |
8190 | @c @item swbreak (default) |
8191 | @c @end table | |
8192 | ||
8193 | @subsubsection Data Cache | |
8194 | The data cache attributes set whether @value{GDBN} will cache target | |
8195 | memory. While this generally improves performance by reducing debug | |
8196 | protocol overhead, it can lead to incorrect results because @value{GDBN} | |
8197 | does not know about volatile variables or memory mapped device | |
8198 | registers. | |
8199 | ||
8200 | @table @code | |
8201 | @item cache | |
b383017d | 8202 | Enable @value{GDBN} to cache target memory. |
6ca652b0 EZ |
8203 | @item nocache |
8204 | Disable @value{GDBN} from caching target memory. This is the default. | |
29e57380 C |
8205 | @end table |
8206 | ||
4b5752d0 VP |
8207 | @subsection Memory Access Checking |
8208 | @value{GDBN} can be instructed to refuse accesses to memory that is | |
8209 | not explicitly described. This can be useful if accessing such | |
8210 | regions has undesired effects for a specific target, or to provide | |
8211 | better error checking. The following commands control this behaviour. | |
8212 | ||
8213 | @table @code | |
8214 | @kindex set mem inaccessible-by-default | |
8215 | @item set mem inaccessible-by-default [on|off] | |
8216 | If @code{on} is specified, make @value{GDBN} treat memory not | |
8217 | explicitly described by the memory ranges as non-existent and refuse accesses | |
8218 | to such memory. The checks are only performed if there's at least one | |
8219 | memory range defined. If @code{off} is specified, make @value{GDBN} | |
8220 | treat the memory not explicitly described by the memory ranges as RAM. | |
56cf5405 | 8221 | The default value is @code{on}. |
4b5752d0 VP |
8222 | @kindex show mem inaccessible-by-default |
8223 | @item show mem inaccessible-by-default | |
8224 | Show the current handling of accesses to unknown memory. | |
8225 | @end table | |
8226 | ||
8227 | ||
29e57380 | 8228 | @c @subsubsection Memory Write Verification |
b383017d | 8229 | @c The memory write verification attributes set whether @value{GDBN} |
29e57380 C |
8230 | @c will re-reads data after each write to verify the write was successful. |
8231 | @c | |
8232 | @c @table @code | |
8233 | @c @item verify | |
8234 | @c @item noverify (default) | |
8235 | @c @end table | |
8236 | ||
16d9dec6 | 8237 | @node Dump/Restore Files |
79a6e687 | 8238 | @section Copy Between Memory and a File |
16d9dec6 MS |
8239 | @cindex dump/restore files |
8240 | @cindex append data to a file | |
8241 | @cindex dump data to a file | |
8242 | @cindex restore data from a file | |
16d9dec6 | 8243 | |
df5215a6 JB |
8244 | You can use the commands @code{dump}, @code{append}, and |
8245 | @code{restore} to copy data between target memory and a file. The | |
8246 | @code{dump} and @code{append} commands write data to a file, and the | |
8247 | @code{restore} command reads data from a file back into the inferior's | |
8248 | memory. Files may be in binary, Motorola S-record, Intel hex, or | |
8249 | Tektronix Hex format; however, @value{GDBN} can only append to binary | |
8250 | files. | |
8251 | ||
8252 | @table @code | |
8253 | ||
8254 | @kindex dump | |
8255 | @item dump @r{[}@var{format}@r{]} memory @var{filename} @var{start_addr} @var{end_addr} | |
8256 | @itemx dump @r{[}@var{format}@r{]} value @var{filename} @var{expr} | |
8257 | Dump the contents of memory from @var{start_addr} to @var{end_addr}, | |
8258 | or the value of @var{expr}, to @var{filename} in the given format. | |
16d9dec6 | 8259 | |
df5215a6 | 8260 | The @var{format} parameter may be any one of: |
16d9dec6 | 8261 | @table @code |
df5215a6 JB |
8262 | @item binary |
8263 | Raw binary form. | |
8264 | @item ihex | |
8265 | Intel hex format. | |
8266 | @item srec | |
8267 | Motorola S-record format. | |
8268 | @item tekhex | |
8269 | Tektronix Hex format. | |
8270 | @end table | |
8271 | ||
8272 | @value{GDBN} uses the same definitions of these formats as the | |
8273 | @sc{gnu} binary utilities, like @samp{objdump} and @samp{objcopy}. If | |
8274 | @var{format} is omitted, @value{GDBN} dumps the data in raw binary | |
8275 | form. | |
8276 | ||
8277 | @kindex append | |
8278 | @item append @r{[}binary@r{]} memory @var{filename} @var{start_addr} @var{end_addr} | |
8279 | @itemx append @r{[}binary@r{]} value @var{filename} @var{expr} | |
8280 | Append the contents of memory from @var{start_addr} to @var{end_addr}, | |
09d4efe1 | 8281 | or the value of @var{expr}, to the file @var{filename}, in raw binary form. |
df5215a6 JB |
8282 | (@value{GDBN} can only append data to files in raw binary form.) |
8283 | ||
8284 | @kindex restore | |
8285 | @item restore @var{filename} @r{[}binary@r{]} @var{bias} @var{start} @var{end} | |
8286 | Restore the contents of file @var{filename} into memory. The | |
8287 | @code{restore} command can automatically recognize any known @sc{bfd} | |
8288 | file format, except for raw binary. To restore a raw binary file you | |
8289 | must specify the optional keyword @code{binary} after the filename. | |
16d9dec6 | 8290 | |
b383017d | 8291 | If @var{bias} is non-zero, its value will be added to the addresses |
16d9dec6 MS |
8292 | contained in the file. Binary files always start at address zero, so |
8293 | they will be restored at address @var{bias}. Other bfd files have | |
8294 | a built-in location; they will be restored at offset @var{bias} | |
8295 | from that location. | |
8296 | ||
8297 | If @var{start} and/or @var{end} are non-zero, then only data between | |
8298 | file offset @var{start} and file offset @var{end} will be restored. | |
b383017d | 8299 | These offsets are relative to the addresses in the file, before |
16d9dec6 MS |
8300 | the @var{bias} argument is applied. |
8301 | ||
8302 | @end table | |
8303 | ||
384ee23f EZ |
8304 | @node Core File Generation |
8305 | @section How to Produce a Core File from Your Program | |
8306 | @cindex dump core from inferior | |
8307 | ||
8308 | A @dfn{core file} or @dfn{core dump} is a file that records the memory | |
8309 | image of a running process and its process status (register values | |
8310 | etc.). Its primary use is post-mortem debugging of a program that | |
8311 | crashed while it ran outside a debugger. A program that crashes | |
8312 | automatically produces a core file, unless this feature is disabled by | |
8313 | the user. @xref{Files}, for information on invoking @value{GDBN} in | |
8314 | the post-mortem debugging mode. | |
8315 | ||
8316 | Occasionally, you may wish to produce a core file of the program you | |
8317 | are debugging in order to preserve a snapshot of its state. | |
8318 | @value{GDBN} has a special command for that. | |
8319 | ||
8320 | @table @code | |
8321 | @kindex gcore | |
8322 | @kindex generate-core-file | |
8323 | @item generate-core-file [@var{file}] | |
8324 | @itemx gcore [@var{file}] | |
8325 | Produce a core dump of the inferior process. The optional argument | |
8326 | @var{file} specifies the file name where to put the core dump. If not | |
8327 | specified, the file name defaults to @file{core.@var{pid}}, where | |
8328 | @var{pid} is the inferior process ID. | |
8329 | ||
8330 | Note that this command is implemented only for some systems (as of | |
8331 | this writing, @sc{gnu}/Linux, FreeBSD, Solaris, Unixware, and S390). | |
8332 | @end table | |
8333 | ||
a0eb71c5 KB |
8334 | @node Character Sets |
8335 | @section Character Sets | |
8336 | @cindex character sets | |
8337 | @cindex charset | |
8338 | @cindex translating between character sets | |
8339 | @cindex host character set | |
8340 | @cindex target character set | |
8341 | ||
8342 | If the program you are debugging uses a different character set to | |
8343 | represent characters and strings than the one @value{GDBN} uses itself, | |
8344 | @value{GDBN} can automatically translate between the character sets for | |
8345 | you. The character set @value{GDBN} uses we call the @dfn{host | |
8346 | character set}; the one the inferior program uses we call the | |
8347 | @dfn{target character set}. | |
8348 | ||
8349 | For example, if you are running @value{GDBN} on a @sc{gnu}/Linux system, which | |
8350 | uses the ISO Latin 1 character set, but you are using @value{GDBN}'s | |
ea35711c | 8351 | remote protocol (@pxref{Remote Debugging}) to debug a program |
a0eb71c5 KB |
8352 | running on an IBM mainframe, which uses the @sc{ebcdic} character set, |
8353 | then the host character set is Latin-1, and the target character set is | |
8354 | @sc{ebcdic}. If you give @value{GDBN} the command @code{set | |
e33d66ec | 8355 | target-charset EBCDIC-US}, then @value{GDBN} translates between |
a0eb71c5 KB |
8356 | @sc{ebcdic} and Latin 1 as you print character or string values, or use |
8357 | character and string literals in expressions. | |
8358 | ||
8359 | @value{GDBN} has no way to automatically recognize which character set | |
8360 | the inferior program uses; you must tell it, using the @code{set | |
8361 | target-charset} command, described below. | |
8362 | ||
8363 | Here are the commands for controlling @value{GDBN}'s character set | |
8364 | support: | |
8365 | ||
8366 | @table @code | |
8367 | @item set target-charset @var{charset} | |
8368 | @kindex set target-charset | |
10af6951 EZ |
8369 | Set the current target character set to @var{charset}. To display the |
8370 | list of supported target character sets, type | |
8371 | @kbd{@w{set target-charset @key{TAB}@key{TAB}}}. | |
a0eb71c5 | 8372 | |
a0eb71c5 KB |
8373 | @item set host-charset @var{charset} |
8374 | @kindex set host-charset | |
8375 | Set the current host character set to @var{charset}. | |
8376 | ||
8377 | By default, @value{GDBN} uses a host character set appropriate to the | |
8378 | system it is running on; you can override that default using the | |
732f6a93 TT |
8379 | @code{set host-charset} command. On some systems, @value{GDBN} cannot |
8380 | automatically determine the appropriate host character set. In this | |
8381 | case, @value{GDBN} uses @samp{UTF-8}. | |
a0eb71c5 KB |
8382 | |
8383 | @value{GDBN} can only use certain character sets as its host character | |
10af6951 EZ |
8384 | set. If you type @kbd{@w{set target-charset @key{TAB}@key{TAB}}}, |
8385 | @value{GDBN} will list the host character sets it supports. | |
a0eb71c5 KB |
8386 | |
8387 | @item set charset @var{charset} | |
8388 | @kindex set charset | |
e33d66ec | 8389 | Set the current host and target character sets to @var{charset}. As |
10af6951 EZ |
8390 | above, if you type @kbd{@w{set charset @key{TAB}@key{TAB}}}, |
8391 | @value{GDBN} will list the names of the character sets that can be used | |
e33d66ec EZ |
8392 | for both host and target. |
8393 | ||
a0eb71c5 | 8394 | @item show charset |
a0eb71c5 | 8395 | @kindex show charset |
10af6951 | 8396 | Show the names of the current host and target character sets. |
e33d66ec | 8397 | |
10af6951 | 8398 | @item show host-charset |
a0eb71c5 | 8399 | @kindex show host-charset |
10af6951 | 8400 | Show the name of the current host character set. |
e33d66ec | 8401 | |
10af6951 | 8402 | @item show target-charset |
a0eb71c5 | 8403 | @kindex show target-charset |
10af6951 | 8404 | Show the name of the current target character set. |
a0eb71c5 | 8405 | |
10af6951 EZ |
8406 | @item set target-wide-charset @var{charset} |
8407 | @kindex set target-wide-charset | |
8408 | Set the current target's wide character set to @var{charset}. This is | |
8409 | the character set used by the target's @code{wchar_t} type. To | |
8410 | display the list of supported wide character sets, type | |
8411 | @kbd{@w{set target-wide-charset @key{TAB}@key{TAB}}}. | |
8412 | ||
8413 | @item show target-wide-charset | |
8414 | @kindex show target-wide-charset | |
8415 | Show the name of the current target's wide character set. | |
a0eb71c5 KB |
8416 | @end table |
8417 | ||
a0eb71c5 KB |
8418 | Here is an example of @value{GDBN}'s character set support in action. |
8419 | Assume that the following source code has been placed in the file | |
8420 | @file{charset-test.c}: | |
8421 | ||
8422 | @smallexample | |
8423 | #include <stdio.h> | |
8424 | ||
8425 | char ascii_hello[] | |
8426 | = @{72, 101, 108, 108, 111, 44, 32, 119, | |
8427 | 111, 114, 108, 100, 33, 10, 0@}; | |
8428 | char ibm1047_hello[] | |
8429 | = @{200, 133, 147, 147, 150, 107, 64, 166, | |
8430 | 150, 153, 147, 132, 90, 37, 0@}; | |
8431 | ||
8432 | main () | |
8433 | @{ | |
8434 | printf ("Hello, world!\n"); | |
8435 | @} | |
10998722 | 8436 | @end smallexample |
a0eb71c5 KB |
8437 | |
8438 | In this program, @code{ascii_hello} and @code{ibm1047_hello} are arrays | |
8439 | containing the string @samp{Hello, world!} followed by a newline, | |
8440 | encoded in the @sc{ascii} and @sc{ibm1047} character sets. | |
8441 | ||
8442 | We compile the program, and invoke the debugger on it: | |
8443 | ||
8444 | @smallexample | |
8445 | $ gcc -g charset-test.c -o charset-test | |
8446 | $ gdb -nw charset-test | |
8447 | GNU gdb 2001-12-19-cvs | |
8448 | Copyright 2001 Free Software Foundation, Inc. | |
8449 | @dots{} | |
f7dc1244 | 8450 | (@value{GDBP}) |
10998722 | 8451 | @end smallexample |
a0eb71c5 KB |
8452 | |
8453 | We can use the @code{show charset} command to see what character sets | |
8454 | @value{GDBN} is currently using to interpret and display characters and | |
8455 | strings: | |
8456 | ||
8457 | @smallexample | |
f7dc1244 | 8458 | (@value{GDBP}) show charset |
e33d66ec | 8459 | The current host and target character set is `ISO-8859-1'. |
f7dc1244 | 8460 | (@value{GDBP}) |
10998722 | 8461 | @end smallexample |
a0eb71c5 KB |
8462 | |
8463 | For the sake of printing this manual, let's use @sc{ascii} as our | |
8464 | initial character set: | |
8465 | @smallexample | |
f7dc1244 EZ |
8466 | (@value{GDBP}) set charset ASCII |
8467 | (@value{GDBP}) show charset | |
e33d66ec | 8468 | The current host and target character set is `ASCII'. |
f7dc1244 | 8469 | (@value{GDBP}) |
10998722 | 8470 | @end smallexample |
a0eb71c5 KB |
8471 | |
8472 | Let's assume that @sc{ascii} is indeed the correct character set for our | |
8473 | host system --- in other words, let's assume that if @value{GDBN} prints | |
8474 | characters using the @sc{ascii} character set, our terminal will display | |
8475 | them properly. Since our current target character set is also | |
8476 | @sc{ascii}, the contents of @code{ascii_hello} print legibly: | |
8477 | ||
8478 | @smallexample | |
f7dc1244 | 8479 | (@value{GDBP}) print ascii_hello |
a0eb71c5 | 8480 | $1 = 0x401698 "Hello, world!\n" |
f7dc1244 | 8481 | (@value{GDBP}) print ascii_hello[0] |
a0eb71c5 | 8482 | $2 = 72 'H' |
f7dc1244 | 8483 | (@value{GDBP}) |
10998722 | 8484 | @end smallexample |
a0eb71c5 KB |
8485 | |
8486 | @value{GDBN} uses the target character set for character and string | |
8487 | literals you use in expressions: | |
8488 | ||
8489 | @smallexample | |
f7dc1244 | 8490 | (@value{GDBP}) print '+' |
a0eb71c5 | 8491 | $3 = 43 '+' |
f7dc1244 | 8492 | (@value{GDBP}) |
10998722 | 8493 | @end smallexample |
a0eb71c5 KB |
8494 | |
8495 | The @sc{ascii} character set uses the number 43 to encode the @samp{+} | |
8496 | character. | |
8497 | ||
8498 | @value{GDBN} relies on the user to tell it which character set the | |
8499 | target program uses. If we print @code{ibm1047_hello} while our target | |
8500 | character set is still @sc{ascii}, we get jibberish: | |
8501 | ||
8502 | @smallexample | |
f7dc1244 | 8503 | (@value{GDBP}) print ibm1047_hello |
a0eb71c5 | 8504 | $4 = 0x4016a8 "\310\205\223\223\226k@@\246\226\231\223\204Z%" |
f7dc1244 | 8505 | (@value{GDBP}) print ibm1047_hello[0] |
a0eb71c5 | 8506 | $5 = 200 '\310' |
f7dc1244 | 8507 | (@value{GDBP}) |
10998722 | 8508 | @end smallexample |
a0eb71c5 | 8509 | |
e33d66ec | 8510 | If we invoke the @code{set target-charset} followed by @key{TAB}@key{TAB}, |
a0eb71c5 KB |
8511 | @value{GDBN} tells us the character sets it supports: |
8512 | ||
8513 | @smallexample | |
f7dc1244 | 8514 | (@value{GDBP}) set target-charset |
b383017d | 8515 | ASCII EBCDIC-US IBM1047 ISO-8859-1 |
f7dc1244 | 8516 | (@value{GDBP}) set target-charset |
10998722 | 8517 | @end smallexample |
a0eb71c5 KB |
8518 | |
8519 | We can select @sc{ibm1047} as our target character set, and examine the | |
8520 | program's strings again. Now the @sc{ascii} string is wrong, but | |
8521 | @value{GDBN} translates the contents of @code{ibm1047_hello} from the | |
8522 | target character set, @sc{ibm1047}, to the host character set, | |
8523 | @sc{ascii}, and they display correctly: | |
8524 | ||
8525 | @smallexample | |
f7dc1244 EZ |
8526 | (@value{GDBP}) set target-charset IBM1047 |
8527 | (@value{GDBP}) show charset | |
e33d66ec EZ |
8528 | The current host character set is `ASCII'. |
8529 | The current target character set is `IBM1047'. | |
f7dc1244 | 8530 | (@value{GDBP}) print ascii_hello |
a0eb71c5 | 8531 | $6 = 0x401698 "\110\145%%?\054\040\167?\162%\144\041\012" |
f7dc1244 | 8532 | (@value{GDBP}) print ascii_hello[0] |
a0eb71c5 | 8533 | $7 = 72 '\110' |
f7dc1244 | 8534 | (@value{GDBP}) print ibm1047_hello |
a0eb71c5 | 8535 | $8 = 0x4016a8 "Hello, world!\n" |
f7dc1244 | 8536 | (@value{GDBP}) print ibm1047_hello[0] |
a0eb71c5 | 8537 | $9 = 200 'H' |
f7dc1244 | 8538 | (@value{GDBP}) |
10998722 | 8539 | @end smallexample |
a0eb71c5 KB |
8540 | |
8541 | As above, @value{GDBN} uses the target character set for character and | |
8542 | string literals you use in expressions: | |
8543 | ||
8544 | @smallexample | |
f7dc1244 | 8545 | (@value{GDBP}) print '+' |
a0eb71c5 | 8546 | $10 = 78 '+' |
f7dc1244 | 8547 | (@value{GDBP}) |
10998722 | 8548 | @end smallexample |
a0eb71c5 | 8549 | |
e33d66ec | 8550 | The @sc{ibm1047} character set uses the number 78 to encode the @samp{+} |
a0eb71c5 KB |
8551 | character. |
8552 | ||
09d4efe1 EZ |
8553 | @node Caching Remote Data |
8554 | @section Caching Data of Remote Targets | |
8555 | @cindex caching data of remote targets | |
8556 | ||
4e5d721f | 8557 | @value{GDBN} caches data exchanged between the debugger and a |
ea35711c | 8558 | remote target (@pxref{Remote Debugging}). Such caching generally improves |
09d4efe1 | 8559 | performance, because it reduces the overhead of the remote protocol by |
4e5d721f DE |
8560 | bundling memory reads and writes into large chunks. Unfortunately, simply |
8561 | caching everything would lead to incorrect results, since @value{GDBN} | |
8562 | does not necessarily know anything about volatile values, memory-mapped I/O | |
29b090c0 DE |
8563 | addresses, etc. Furthermore, in non-stop mode (@pxref{Non-Stop Mode}) |
8564 | memory can be changed @emph{while} a gdb command is executing. | |
8565 | Therefore, by default, @value{GDBN} only caches data | |
8566 | known to be on the stack@footnote{In non-stop mode, it is moderately | |
8567 | rare for a running thread to modify the stack of a stopped thread | |
8568 | in a way that would interfere with a backtrace, and caching of | |
8569 | stack reads provides a significant speed up of remote backtraces.}. | |
8570 | Other regions of memory can be explicitly marked as | |
4e5d721f | 8571 | cacheable; see @pxref{Memory Region Attributes}. |
09d4efe1 EZ |
8572 | |
8573 | @table @code | |
8574 | @kindex set remotecache | |
8575 | @item set remotecache on | |
8576 | @itemx set remotecache off | |
4e5d721f DE |
8577 | This option no longer does anything; it exists for compatibility |
8578 | with old scripts. | |
09d4efe1 EZ |
8579 | |
8580 | @kindex show remotecache | |
8581 | @item show remotecache | |
4e5d721f DE |
8582 | Show the current state of the obsolete remotecache flag. |
8583 | ||
8584 | @kindex set stack-cache | |
8585 | @item set stack-cache on | |
8586 | @itemx set stack-cache off | |
8587 | Enable or disable caching of stack accesses. When @code{ON}, use | |
8588 | caching. By default, this option is @code{ON}. | |
8589 | ||
8590 | @kindex show stack-cache | |
8591 | @item show stack-cache | |
8592 | Show the current state of data caching for memory accesses. | |
09d4efe1 EZ |
8593 | |
8594 | @kindex info dcache | |
4e5d721f | 8595 | @item info dcache @r{[}line@r{]} |
09d4efe1 | 8596 | Print the information about the data cache performance. The |
4e5d721f DE |
8597 | information displayed includes the dcache width and depth, and for |
8598 | each cache line, its number, address, and how many times it was | |
8599 | referenced. This command is useful for debugging the data cache | |
8600 | operation. | |
8601 | ||
8602 | If a line number is specified, the contents of that line will be | |
8603 | printed in hex. | |
09d4efe1 EZ |
8604 | @end table |
8605 | ||
08388c79 DE |
8606 | @node Searching Memory |
8607 | @section Search Memory | |
8608 | @cindex searching memory | |
8609 | ||
8610 | Memory can be searched for a particular sequence of bytes with the | |
8611 | @code{find} command. | |
8612 | ||
8613 | @table @code | |
8614 | @kindex find | |
8615 | @item find @r{[}/@var{sn}@r{]} @var{start_addr}, +@var{len}, @var{val1} @r{[}, @var{val2}, @dots{}@r{]} | |
8616 | @itemx find @r{[}/@var{sn}@r{]} @var{start_addr}, @var{end_addr}, @var{val1} @r{[}, @var{val2}, @dots{}@r{]} | |
8617 | Search memory for the sequence of bytes specified by @var{val1}, @var{val2}, | |
8618 | etc. The search begins at address @var{start_addr} and continues for either | |
8619 | @var{len} bytes or through to @var{end_addr} inclusive. | |
8620 | @end table | |
8621 | ||
8622 | @var{s} and @var{n} are optional parameters. | |
8623 | They may be specified in either order, apart or together. | |
8624 | ||
8625 | @table @r | |
8626 | @item @var{s}, search query size | |
8627 | The size of each search query value. | |
8628 | ||
8629 | @table @code | |
8630 | @item b | |
8631 | bytes | |
8632 | @item h | |
8633 | halfwords (two bytes) | |
8634 | @item w | |
8635 | words (four bytes) | |
8636 | @item g | |
8637 | giant words (eight bytes) | |
8638 | @end table | |
8639 | ||
8640 | All values are interpreted in the current language. | |
8641 | This means, for example, that if the current source language is C/C@t{++} | |
8642 | then searching for the string ``hello'' includes the trailing '\0'. | |
8643 | ||
8644 | If the value size is not specified, it is taken from the | |
8645 | value's type in the current language. | |
8646 | This is useful when one wants to specify the search | |
8647 | pattern as a mixture of types. | |
8648 | Note that this means, for example, that in the case of C-like languages | |
8649 | a search for an untyped 0x42 will search for @samp{(int) 0x42} | |
8650 | which is typically four bytes. | |
8651 | ||
8652 | @item @var{n}, maximum number of finds | |
8653 | The maximum number of matches to print. The default is to print all finds. | |
8654 | @end table | |
8655 | ||
8656 | You can use strings as search values. Quote them with double-quotes | |
8657 | (@code{"}). | |
8658 | The string value is copied into the search pattern byte by byte, | |
8659 | regardless of the endianness of the target and the size specification. | |
8660 | ||
8661 | The address of each match found is printed as well as a count of the | |
8662 | number of matches found. | |
8663 | ||
8664 | The address of the last value found is stored in convenience variable | |
8665 | @samp{$_}. | |
8666 | A count of the number of matches is stored in @samp{$numfound}. | |
8667 | ||
8668 | For example, if stopped at the @code{printf} in this function: | |
8669 | ||
8670 | @smallexample | |
8671 | void | |
8672 | hello () | |
8673 | @{ | |
8674 | static char hello[] = "hello-hello"; | |
8675 | static struct @{ char c; short s; int i; @} | |
8676 | __attribute__ ((packed)) mixed | |
8677 | = @{ 'c', 0x1234, 0x87654321 @}; | |
8678 | printf ("%s\n", hello); | |
8679 | @} | |
8680 | @end smallexample | |
8681 | ||
8682 | @noindent | |
8683 | you get during debugging: | |
8684 | ||
8685 | @smallexample | |
8686 | (gdb) find &hello[0], +sizeof(hello), "hello" | |
8687 | 0x804956d <hello.1620+6> | |
8688 | 1 pattern found | |
8689 | (gdb) find &hello[0], +sizeof(hello), 'h', 'e', 'l', 'l', 'o' | |
8690 | 0x8049567 <hello.1620> | |
8691 | 0x804956d <hello.1620+6> | |
8692 | 2 patterns found | |
8693 | (gdb) find /b1 &hello[0], +sizeof(hello), 'h', 0x65, 'l' | |
8694 | 0x8049567 <hello.1620> | |
8695 | 1 pattern found | |
8696 | (gdb) find &mixed, +sizeof(mixed), (char) 'c', (short) 0x1234, (int) 0x87654321 | |
8697 | 0x8049560 <mixed.1625> | |
8698 | 1 pattern found | |
8699 | (gdb) print $numfound | |
8700 | $1 = 1 | |
8701 | (gdb) print $_ | |
8702 | $2 = (void *) 0x8049560 | |
8703 | @end smallexample | |
a0eb71c5 | 8704 | |
edb3359d DJ |
8705 | @node Optimized Code |
8706 | @chapter Debugging Optimized Code | |
8707 | @cindex optimized code, debugging | |
8708 | @cindex debugging optimized code | |
8709 | ||
8710 | Almost all compilers support optimization. With optimization | |
8711 | disabled, the compiler generates assembly code that corresponds | |
8712 | directly to your source code, in a simplistic way. As the compiler | |
8713 | applies more powerful optimizations, the generated assembly code | |
8714 | diverges from your original source code. With help from debugging | |
8715 | information generated by the compiler, @value{GDBN} can map from | |
8716 | the running program back to constructs from your original source. | |
8717 | ||
8718 | @value{GDBN} is more accurate with optimization disabled. If you | |
8719 | can recompile without optimization, it is easier to follow the | |
8720 | progress of your program during debugging. But, there are many cases | |
8721 | where you may need to debug an optimized version. | |
8722 | ||
8723 | When you debug a program compiled with @samp{-g -O}, remember that the | |
8724 | optimizer has rearranged your code; the debugger shows you what is | |
8725 | really there. Do not be too surprised when the execution path does not | |
8726 | exactly match your source file! An extreme example: if you define a | |
8727 | variable, but never use it, @value{GDBN} never sees that | |
8728 | variable---because the compiler optimizes it out of existence. | |
8729 | ||
8730 | Some things do not work as well with @samp{-g -O} as with just | |
8731 | @samp{-g}, particularly on machines with instruction scheduling. If in | |
8732 | doubt, recompile with @samp{-g} alone, and if this fixes the problem, | |
8733 | please report it to us as a bug (including a test case!). | |
8734 | @xref{Variables}, for more information about debugging optimized code. | |
8735 | ||
8736 | @menu | |
8737 | * Inline Functions:: How @value{GDBN} presents inlining | |
8738 | @end menu | |
8739 | ||
8740 | @node Inline Functions | |
8741 | @section Inline Functions | |
8742 | @cindex inline functions, debugging | |
8743 | ||
8744 | @dfn{Inlining} is an optimization that inserts a copy of the function | |
8745 | body directly at each call site, instead of jumping to a shared | |
8746 | routine. @value{GDBN} displays inlined functions just like | |
8747 | non-inlined functions. They appear in backtraces. You can view their | |
8748 | arguments and local variables, step into them with @code{step}, skip | |
8749 | them with @code{next}, and escape from them with @code{finish}. | |
8750 | You can check whether a function was inlined by using the | |
8751 | @code{info frame} command. | |
8752 | ||
8753 | For @value{GDBN} to support inlined functions, the compiler must | |
8754 | record information about inlining in the debug information --- | |
8755 | @value{NGCC} using the @sc{dwarf 2} format does this, and several | |
8756 | other compilers do also. @value{GDBN} only supports inlined functions | |
8757 | when using @sc{dwarf 2}. Versions of @value{NGCC} before 4.1 | |
8758 | do not emit two required attributes (@samp{DW_AT_call_file} and | |
8759 | @samp{DW_AT_call_line}); @value{GDBN} does not display inlined | |
8760 | function calls with earlier versions of @value{NGCC}. It instead | |
8761 | displays the arguments and local variables of inlined functions as | |
8762 | local variables in the caller. | |
8763 | ||
8764 | The body of an inlined function is directly included at its call site; | |
8765 | unlike a non-inlined function, there are no instructions devoted to | |
8766 | the call. @value{GDBN} still pretends that the call site and the | |
8767 | start of the inlined function are different instructions. Stepping to | |
8768 | the call site shows the call site, and then stepping again shows | |
8769 | the first line of the inlined function, even though no additional | |
8770 | instructions are executed. | |
8771 | ||
8772 | This makes source-level debugging much clearer; you can see both the | |
8773 | context of the call and then the effect of the call. Only stepping by | |
8774 | a single instruction using @code{stepi} or @code{nexti} does not do | |
8775 | this; single instruction steps always show the inlined body. | |
8776 | ||
8777 | There are some ways that @value{GDBN} does not pretend that inlined | |
8778 | function calls are the same as normal calls: | |
8779 | ||
8780 | @itemize @bullet | |
8781 | @item | |
8782 | You cannot set breakpoints on inlined functions. @value{GDBN} | |
8783 | either reports that there is no symbol with that name, or else sets the | |
8784 | breakpoint only on non-inlined copies of the function. This limitation | |
8785 | will be removed in a future version of @value{GDBN}; until then, | |
8786 | set a breakpoint by line number on the first line of the inlined | |
8787 | function instead. | |
8788 | ||
8789 | @item | |
8790 | Setting breakpoints at the call site of an inlined function may not | |
8791 | work, because the call site does not contain any code. @value{GDBN} | |
8792 | may incorrectly move the breakpoint to the next line of the enclosing | |
8793 | function, after the call. This limitation will be removed in a future | |
8794 | version of @value{GDBN}; until then, set a breakpoint on an earlier line | |
8795 | or inside the inlined function instead. | |
8796 | ||
8797 | @item | |
8798 | @value{GDBN} cannot locate the return value of inlined calls after | |
8799 | using the @code{finish} command. This is a limitation of compiler-generated | |
8800 | debugging information; after @code{finish}, you can step to the next line | |
8801 | and print a variable where your program stored the return value. | |
8802 | ||
8803 | @end itemize | |
8804 | ||
8805 | ||
e2e0bcd1 JB |
8806 | @node Macros |
8807 | @chapter C Preprocessor Macros | |
8808 | ||
49efadf5 | 8809 | Some languages, such as C and C@t{++}, provide a way to define and invoke |
e2e0bcd1 JB |
8810 | ``preprocessor macros'' which expand into strings of tokens. |
8811 | @value{GDBN} can evaluate expressions containing macro invocations, show | |
8812 | the result of macro expansion, and show a macro's definition, including | |
8813 | where it was defined. | |
8814 | ||
8815 | You may need to compile your program specially to provide @value{GDBN} | |
8816 | with information about preprocessor macros. Most compilers do not | |
8817 | include macros in their debugging information, even when you compile | |
8818 | with the @option{-g} flag. @xref{Compilation}. | |
8819 | ||
8820 | A program may define a macro at one point, remove that definition later, | |
8821 | and then provide a different definition after that. Thus, at different | |
8822 | points in the program, a macro may have different definitions, or have | |
8823 | no definition at all. If there is a current stack frame, @value{GDBN} | |
8824 | uses the macros in scope at that frame's source code line. Otherwise, | |
8825 | @value{GDBN} uses the macros in scope at the current listing location; | |
8826 | see @ref{List}. | |
8827 | ||
e2e0bcd1 JB |
8828 | Whenever @value{GDBN} evaluates an expression, it always expands any |
8829 | macro invocations present in the expression. @value{GDBN} also provides | |
8830 | the following commands for working with macros explicitly. | |
8831 | ||
8832 | @table @code | |
8833 | ||
8834 | @kindex macro expand | |
8835 | @cindex macro expansion, showing the results of preprocessor | |
8836 | @cindex preprocessor macro expansion, showing the results of | |
8837 | @cindex expanding preprocessor macros | |
8838 | @item macro expand @var{expression} | |
8839 | @itemx macro exp @var{expression} | |
8840 | Show the results of expanding all preprocessor macro invocations in | |
8841 | @var{expression}. Since @value{GDBN} simply expands macros, but does | |
8842 | not parse the result, @var{expression} need not be a valid expression; | |
8843 | it can be any string of tokens. | |
8844 | ||
09d4efe1 | 8845 | @kindex macro exp1 |
e2e0bcd1 JB |
8846 | @item macro expand-once @var{expression} |
8847 | @itemx macro exp1 @var{expression} | |
4644b6e3 | 8848 | @cindex expand macro once |
e2e0bcd1 JB |
8849 | @i{(This command is not yet implemented.)} Show the results of |
8850 | expanding those preprocessor macro invocations that appear explicitly in | |
8851 | @var{expression}. Macro invocations appearing in that expansion are | |
8852 | left unchanged. This command allows you to see the effect of a | |
8853 | particular macro more clearly, without being confused by further | |
8854 | expansions. Since @value{GDBN} simply expands macros, but does not | |
8855 | parse the result, @var{expression} need not be a valid expression; it | |
8856 | can be any string of tokens. | |
8857 | ||
475b0867 | 8858 | @kindex info macro |
e2e0bcd1 JB |
8859 | @cindex macro definition, showing |
8860 | @cindex definition, showing a macro's | |
475b0867 | 8861 | @item info macro @var{macro} |
e2e0bcd1 | 8862 | Show the definition of the macro named @var{macro}, and describe the |
484086b7 | 8863 | source location or compiler command-line where that definition was established. |
e2e0bcd1 JB |
8864 | |
8865 | @kindex macro define | |
8866 | @cindex user-defined macros | |
8867 | @cindex defining macros interactively | |
8868 | @cindex macros, user-defined | |
8869 | @item macro define @var{macro} @var{replacement-list} | |
8870 | @itemx macro define @var{macro}(@var{arglist}) @var{replacement-list} | |
d7d9f01e TT |
8871 | Introduce a definition for a preprocessor macro named @var{macro}, |
8872 | invocations of which are replaced by the tokens given in | |
8873 | @var{replacement-list}. The first form of this command defines an | |
8874 | ``object-like'' macro, which takes no arguments; the second form | |
8875 | defines a ``function-like'' macro, which takes the arguments given in | |
8876 | @var{arglist}. | |
8877 | ||
8878 | A definition introduced by this command is in scope in every | |
8879 | expression evaluated in @value{GDBN}, until it is removed with the | |
8880 | @code{macro undef} command, described below. The definition overrides | |
8881 | all definitions for @var{macro} present in the program being debugged, | |
8882 | as well as any previous user-supplied definition. | |
e2e0bcd1 JB |
8883 | |
8884 | @kindex macro undef | |
8885 | @item macro undef @var{macro} | |
d7d9f01e TT |
8886 | Remove any user-supplied definition for the macro named @var{macro}. |
8887 | This command only affects definitions provided with the @code{macro | |
8888 | define} command, described above; it cannot remove definitions present | |
8889 | in the program being debugged. | |
e2e0bcd1 | 8890 | |
09d4efe1 EZ |
8891 | @kindex macro list |
8892 | @item macro list | |
d7d9f01e | 8893 | List all the macros defined using the @code{macro define} command. |
e2e0bcd1 JB |
8894 | @end table |
8895 | ||
8896 | @cindex macros, example of debugging with | |
8897 | Here is a transcript showing the above commands in action. First, we | |
8898 | show our source files: | |
8899 | ||
8900 | @smallexample | |
8901 | $ cat sample.c | |
8902 | #include <stdio.h> | |
8903 | #include "sample.h" | |
8904 | ||
8905 | #define M 42 | |
8906 | #define ADD(x) (M + x) | |
8907 | ||
8908 | main () | |
8909 | @{ | |
8910 | #define N 28 | |
8911 | printf ("Hello, world!\n"); | |
8912 | #undef N | |
8913 | printf ("We're so creative.\n"); | |
8914 | #define N 1729 | |
8915 | printf ("Goodbye, world!\n"); | |
8916 | @} | |
8917 | $ cat sample.h | |
8918 | #define Q < | |
8919 | $ | |
8920 | @end smallexample | |
8921 | ||
8922 | Now, we compile the program using the @sc{gnu} C compiler, @value{NGCC}. | |
8923 | We pass the @option{-gdwarf-2} and @option{-g3} flags to ensure the | |
8924 | compiler includes information about preprocessor macros in the debugging | |
8925 | information. | |
8926 | ||
8927 | @smallexample | |
8928 | $ gcc -gdwarf-2 -g3 sample.c -o sample | |
8929 | $ | |
8930 | @end smallexample | |
8931 | ||
8932 | Now, we start @value{GDBN} on our sample program: | |
8933 | ||
8934 | @smallexample | |
8935 | $ gdb -nw sample | |
8936 | GNU gdb 2002-05-06-cvs | |
8937 | Copyright 2002 Free Software Foundation, Inc. | |
8938 | GDB is free software, @dots{} | |
f7dc1244 | 8939 | (@value{GDBP}) |
e2e0bcd1 JB |
8940 | @end smallexample |
8941 | ||
8942 | We can expand macros and examine their definitions, even when the | |
8943 | program is not running. @value{GDBN} uses the current listing position | |
8944 | to decide which macro definitions are in scope: | |
8945 | ||
8946 | @smallexample | |
f7dc1244 | 8947 | (@value{GDBP}) list main |
e2e0bcd1 JB |
8948 | 3 |
8949 | 4 #define M 42 | |
8950 | 5 #define ADD(x) (M + x) | |
8951 | 6 | |
8952 | 7 main () | |
8953 | 8 @{ | |
8954 | 9 #define N 28 | |
8955 | 10 printf ("Hello, world!\n"); | |
8956 | 11 #undef N | |
8957 | 12 printf ("We're so creative.\n"); | |
f7dc1244 | 8958 | (@value{GDBP}) info macro ADD |
e2e0bcd1 JB |
8959 | Defined at /home/jimb/gdb/macros/play/sample.c:5 |
8960 | #define ADD(x) (M + x) | |
f7dc1244 | 8961 | (@value{GDBP}) info macro Q |
e2e0bcd1 JB |
8962 | Defined at /home/jimb/gdb/macros/play/sample.h:1 |
8963 | included at /home/jimb/gdb/macros/play/sample.c:2 | |
8964 | #define Q < | |
f7dc1244 | 8965 | (@value{GDBP}) macro expand ADD(1) |
e2e0bcd1 | 8966 | expands to: (42 + 1) |
f7dc1244 | 8967 | (@value{GDBP}) macro expand-once ADD(1) |
e2e0bcd1 | 8968 | expands to: once (M + 1) |
f7dc1244 | 8969 | (@value{GDBP}) |
e2e0bcd1 JB |
8970 | @end smallexample |
8971 | ||
d7d9f01e | 8972 | In the example above, note that @code{macro expand-once} expands only |
e2e0bcd1 JB |
8973 | the macro invocation explicit in the original text --- the invocation of |
8974 | @code{ADD} --- but does not expand the invocation of the macro @code{M}, | |
8975 | which was introduced by @code{ADD}. | |
8976 | ||
3f94c067 BW |
8977 | Once the program is running, @value{GDBN} uses the macro definitions in |
8978 | force at the source line of the current stack frame: | |
e2e0bcd1 JB |
8979 | |
8980 | @smallexample | |
f7dc1244 | 8981 | (@value{GDBP}) break main |
e2e0bcd1 | 8982 | Breakpoint 1 at 0x8048370: file sample.c, line 10. |
f7dc1244 | 8983 | (@value{GDBP}) run |
b383017d | 8984 | Starting program: /home/jimb/gdb/macros/play/sample |
e2e0bcd1 JB |
8985 | |
8986 | Breakpoint 1, main () at sample.c:10 | |
8987 | 10 printf ("Hello, world!\n"); | |
f7dc1244 | 8988 | (@value{GDBP}) |
e2e0bcd1 JB |
8989 | @end smallexample |
8990 | ||
8991 | At line 10, the definition of the macro @code{N} at line 9 is in force: | |
8992 | ||
8993 | @smallexample | |
f7dc1244 | 8994 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
8995 | Defined at /home/jimb/gdb/macros/play/sample.c:9 |
8996 | #define N 28 | |
f7dc1244 | 8997 | (@value{GDBP}) macro expand N Q M |
e2e0bcd1 | 8998 | expands to: 28 < 42 |
f7dc1244 | 8999 | (@value{GDBP}) print N Q M |
e2e0bcd1 | 9000 | $1 = 1 |
f7dc1244 | 9001 | (@value{GDBP}) |
e2e0bcd1 JB |
9002 | @end smallexample |
9003 | ||
9004 | As we step over directives that remove @code{N}'s definition, and then | |
9005 | give it a new definition, @value{GDBN} finds the definition (or lack | |
9006 | thereof) in force at each point: | |
9007 | ||
9008 | @smallexample | |
f7dc1244 | 9009 | (@value{GDBP}) next |
e2e0bcd1 JB |
9010 | Hello, world! |
9011 | 12 printf ("We're so creative.\n"); | |
f7dc1244 | 9012 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
9013 | The symbol `N' has no definition as a C/C++ preprocessor macro |
9014 | at /home/jimb/gdb/macros/play/sample.c:12 | |
f7dc1244 | 9015 | (@value{GDBP}) next |
e2e0bcd1 JB |
9016 | We're so creative. |
9017 | 14 printf ("Goodbye, world!\n"); | |
f7dc1244 | 9018 | (@value{GDBP}) info macro N |
e2e0bcd1 JB |
9019 | Defined at /home/jimb/gdb/macros/play/sample.c:13 |
9020 | #define N 1729 | |
f7dc1244 | 9021 | (@value{GDBP}) macro expand N Q M |
e2e0bcd1 | 9022 | expands to: 1729 < 42 |
f7dc1244 | 9023 | (@value{GDBP}) print N Q M |
e2e0bcd1 | 9024 | $2 = 0 |
f7dc1244 | 9025 | (@value{GDBP}) |
e2e0bcd1 JB |
9026 | @end smallexample |
9027 | ||
484086b7 JK |
9028 | In addition to source files, macros can be defined on the compilation command |
9029 | line using the @option{-D@var{name}=@var{value}} syntax. For macros defined in | |
9030 | such a way, @value{GDBN} displays the location of their definition as line zero | |
9031 | of the source file submitted to the compiler. | |
9032 | ||
9033 | @smallexample | |
9034 | (@value{GDBP}) info macro __STDC__ | |
9035 | Defined at /home/jimb/gdb/macros/play/sample.c:0 | |
9036 | -D__STDC__=1 | |
9037 | (@value{GDBP}) | |
9038 | @end smallexample | |
9039 | ||
e2e0bcd1 | 9040 | |
b37052ae EZ |
9041 | @node Tracepoints |
9042 | @chapter Tracepoints | |
9043 | @c This chapter is based on the documentation written by Michael | |
9044 | @c Snyder, David Taylor, Jim Blandy, and Elena Zannoni. | |
9045 | ||
9046 | @cindex tracepoints | |
9047 | In some applications, it is not feasible for the debugger to interrupt | |
9048 | the program's execution long enough for the developer to learn | |
9049 | anything helpful about its behavior. If the program's correctness | |
9050 | depends on its real-time behavior, delays introduced by a debugger | |
9051 | might cause the program to change its behavior drastically, or perhaps | |
9052 | fail, even when the code itself is correct. It is useful to be able | |
9053 | to observe the program's behavior without interrupting it. | |
9054 | ||
9055 | Using @value{GDBN}'s @code{trace} and @code{collect} commands, you can | |
9056 | specify locations in the program, called @dfn{tracepoints}, and | |
9057 | arbitrary expressions to evaluate when those tracepoints are reached. | |
9058 | Later, using the @code{tfind} command, you can examine the values | |
9059 | those expressions had when the program hit the tracepoints. The | |
9060 | expressions may also denote objects in memory---structures or arrays, | |
9061 | for example---whose values @value{GDBN} should record; while visiting | |
9062 | a particular tracepoint, you may inspect those objects as if they were | |
9063 | in memory at that moment. However, because @value{GDBN} records these | |
9064 | values without interacting with you, it can do so quickly and | |
9065 | unobtrusively, hopefully not disturbing the program's behavior. | |
9066 | ||
9067 | The tracepoint facility is currently available only for remote | |
9d29849a JB |
9068 | targets. @xref{Targets}. In addition, your remote target must know |
9069 | how to collect trace data. This functionality is implemented in the | |
9070 | remote stub; however, none of the stubs distributed with @value{GDBN} | |
9071 | support tracepoints as of this writing. The format of the remote | |
9072 | packets used to implement tracepoints are described in @ref{Tracepoint | |
9073 | Packets}. | |
b37052ae EZ |
9074 | |
9075 | This chapter describes the tracepoint commands and features. | |
9076 | ||
9077 | @menu | |
b383017d RM |
9078 | * Set Tracepoints:: |
9079 | * Analyze Collected Data:: | |
9080 | * Tracepoint Variables:: | |
b37052ae EZ |
9081 | @end menu |
9082 | ||
9083 | @node Set Tracepoints | |
9084 | @section Commands to Set Tracepoints | |
9085 | ||
9086 | Before running such a @dfn{trace experiment}, an arbitrary number of | |
1042e4c0 SS |
9087 | tracepoints can be set. A tracepoint is actually a special type of |
9088 | breakpoint (@pxref{Set Breaks}), so you can manipulate it using | |
9089 | standard breakpoint commands. For instance, as with breakpoints, | |
9090 | tracepoint numbers are successive integers starting from one, and many | |
9091 | of the commands associated with tracepoints take the tracepoint number | |
9092 | as their argument, to identify which tracepoint to work on. | |
b37052ae EZ |
9093 | |
9094 | For each tracepoint, you can specify, in advance, some arbitrary set | |
9095 | of data that you want the target to collect in the trace buffer when | |
9096 | it hits that tracepoint. The collected data can include registers, | |
9097 | local variables, or global data. Later, you can use @value{GDBN} | |
9098 | commands to examine the values these data had at the time the | |
9099 | tracepoint was hit. | |
9100 | ||
1042e4c0 SS |
9101 | Tracepoints do not support every breakpoint feature. Conditional |
9102 | expressions and ignore counts on tracepoints have no effect, and | |
9103 | tracepoints cannot run @value{GDBN} commands when they are | |
9104 | hit. Tracepoints may not be thread-specific either. | |
9105 | ||
b37052ae EZ |
9106 | This section describes commands to set tracepoints and associated |
9107 | conditions and actions. | |
9108 | ||
9109 | @menu | |
b383017d RM |
9110 | * Create and Delete Tracepoints:: |
9111 | * Enable and Disable Tracepoints:: | |
9112 | * Tracepoint Passcounts:: | |
782b2b07 | 9113 | * Tracepoint Conditions:: |
b383017d RM |
9114 | * Tracepoint Actions:: |
9115 | * Listing Tracepoints:: | |
79a6e687 | 9116 | * Starting and Stopping Trace Experiments:: |
b37052ae EZ |
9117 | @end menu |
9118 | ||
9119 | @node Create and Delete Tracepoints | |
9120 | @subsection Create and Delete Tracepoints | |
9121 | ||
9122 | @table @code | |
9123 | @cindex set tracepoint | |
9124 | @kindex trace | |
1042e4c0 | 9125 | @item trace @var{location} |
b37052ae | 9126 | The @code{trace} command is very similar to the @code{break} command. |
1042e4c0 SS |
9127 | Its argument @var{location} can be a source line, a function name, or |
9128 | an address in the target program. @xref{Specify Location}. The | |
9129 | @code{trace} command defines a tracepoint, which is a point in the | |
9130 | target program where the debugger will briefly stop, collect some | |
9131 | data, and then allow the program to continue. Setting a tracepoint or | |
9132 | changing its actions doesn't take effect until the next @code{tstart} | |
9133 | command, and once a trace experiment is running, further changes will | |
9134 | not have any effect until the next trace experiment starts. | |
b37052ae EZ |
9135 | |
9136 | Here are some examples of using the @code{trace} command: | |
9137 | ||
9138 | @smallexample | |
9139 | (@value{GDBP}) @b{trace foo.c:121} // a source file and line number | |
9140 | ||
9141 | (@value{GDBP}) @b{trace +2} // 2 lines forward | |
9142 | ||
9143 | (@value{GDBP}) @b{trace my_function} // first source line of function | |
9144 | ||
9145 | (@value{GDBP}) @b{trace *my_function} // EXACT start address of function | |
9146 | ||
9147 | (@value{GDBP}) @b{trace *0x2117c4} // an address | |
9148 | @end smallexample | |
9149 | ||
9150 | @noindent | |
9151 | You can abbreviate @code{trace} as @code{tr}. | |
9152 | ||
782b2b07 SS |
9153 | @item trace @var{location} if @var{cond} |
9154 | Set a tracepoint with condition @var{cond}; evaluate the expression | |
9155 | @var{cond} each time the tracepoint is reached, and collect data only | |
9156 | if the value is nonzero---that is, if @var{cond} evaluates as true. | |
9157 | @xref{Tracepoint Conditions, ,Tracepoint Conditions}, for more | |
9158 | information on tracepoint conditions. | |
9159 | ||
b37052ae EZ |
9160 | @vindex $tpnum |
9161 | @cindex last tracepoint number | |
9162 | @cindex recent tracepoint number | |
9163 | @cindex tracepoint number | |
9164 | The convenience variable @code{$tpnum} records the tracepoint number | |
9165 | of the most recently set tracepoint. | |
9166 | ||
9167 | @kindex delete tracepoint | |
9168 | @cindex tracepoint deletion | |
9169 | @item delete tracepoint @r{[}@var{num}@r{]} | |
9170 | Permanently delete one or more tracepoints. With no argument, the | |
1042e4c0 SS |
9171 | default is to delete all tracepoints. Note that the regular |
9172 | @code{delete} command can remove tracepoints also. | |
b37052ae EZ |
9173 | |
9174 | Examples: | |
9175 | ||
9176 | @smallexample | |
9177 | (@value{GDBP}) @b{delete trace 1 2 3} // remove three tracepoints | |
9178 | ||
9179 | (@value{GDBP}) @b{delete trace} // remove all tracepoints | |
9180 | @end smallexample | |
9181 | ||
9182 | @noindent | |
9183 | You can abbreviate this command as @code{del tr}. | |
9184 | @end table | |
9185 | ||
9186 | @node Enable and Disable Tracepoints | |
9187 | @subsection Enable and Disable Tracepoints | |
9188 | ||
1042e4c0 SS |
9189 | These commands are deprecated; they are equivalent to plain @code{disable} and @code{enable}. |
9190 | ||
b37052ae EZ |
9191 | @table @code |
9192 | @kindex disable tracepoint | |
9193 | @item disable tracepoint @r{[}@var{num}@r{]} | |
9194 | Disable tracepoint @var{num}, or all tracepoints if no argument | |
9195 | @var{num} is given. A disabled tracepoint will have no effect during | |
9196 | the next trace experiment, but it is not forgotten. You can re-enable | |
9197 | a disabled tracepoint using the @code{enable tracepoint} command. | |
9198 | ||
9199 | @kindex enable tracepoint | |
9200 | @item enable tracepoint @r{[}@var{num}@r{]} | |
9201 | Enable tracepoint @var{num}, or all tracepoints. The enabled | |
9202 | tracepoints will become effective the next time a trace experiment is | |
9203 | run. | |
9204 | @end table | |
9205 | ||
9206 | @node Tracepoint Passcounts | |
9207 | @subsection Tracepoint Passcounts | |
9208 | ||
9209 | @table @code | |
9210 | @kindex passcount | |
9211 | @cindex tracepoint pass count | |
9212 | @item passcount @r{[}@var{n} @r{[}@var{num}@r{]]} | |
9213 | Set the @dfn{passcount} of a tracepoint. The passcount is a way to | |
9214 | automatically stop a trace experiment. If a tracepoint's passcount is | |
9215 | @var{n}, then the trace experiment will be automatically stopped on | |
9216 | the @var{n}'th time that tracepoint is hit. If the tracepoint number | |
9217 | @var{num} is not specified, the @code{passcount} command sets the | |
9218 | passcount of the most recently defined tracepoint. If no passcount is | |
9219 | given, the trace experiment will run until stopped explicitly by the | |
9220 | user. | |
9221 | ||
9222 | Examples: | |
9223 | ||
9224 | @smallexample | |
b383017d | 9225 | (@value{GDBP}) @b{passcount 5 2} // Stop on the 5th execution of |
6826cf00 | 9226 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// tracepoint 2} |
b37052ae EZ |
9227 | |
9228 | (@value{GDBP}) @b{passcount 12} // Stop on the 12th execution of the | |
6826cf00 | 9229 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// most recently defined tracepoint.} |
b37052ae EZ |
9230 | (@value{GDBP}) @b{trace foo} |
9231 | (@value{GDBP}) @b{pass 3} | |
9232 | (@value{GDBP}) @b{trace bar} | |
9233 | (@value{GDBP}) @b{pass 2} | |
9234 | (@value{GDBP}) @b{trace baz} | |
9235 | (@value{GDBP}) @b{pass 1} // Stop tracing when foo has been | |
6826cf00 EZ |
9236 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// executed 3 times OR when bar has} |
9237 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// been executed 2 times} | |
9238 | @exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// OR when baz has been executed 1 time.} | |
b37052ae EZ |
9239 | @end smallexample |
9240 | @end table | |
9241 | ||
782b2b07 SS |
9242 | @node Tracepoint Conditions |
9243 | @subsection Tracepoint Conditions | |
9244 | @cindex conditional tracepoints | |
9245 | @cindex tracepoint conditions | |
9246 | ||
9247 | The simplest sort of tracepoint collects data every time your program | |
9248 | reaches a specified place. You can also specify a @dfn{condition} for | |
9249 | a tracepoint. A condition is just a Boolean expression in your | |
9250 | programming language (@pxref{Expressions, ,Expressions}). A | |
9251 | tracepoint with a condition evaluates the expression each time your | |
9252 | program reaches it, and data collection happens only if the condition | |
9253 | is true. | |
9254 | ||
9255 | Tracepoint conditions can be specified when a tracepoint is set, by | |
9256 | using @samp{if} in the arguments to the @code{trace} command. | |
9257 | @xref{Create and Delete Tracepoints, ,Setting Tracepoints}. They can | |
9258 | also be set or changed at any time with the @code{condition} command, | |
9259 | just as with breakpoints. | |
9260 | ||
9261 | Unlike breakpoint conditions, @value{GDBN} does not actually evaluate | |
9262 | the conditional expression itself. Instead, @value{GDBN} encodes the | |
9263 | expression into an agent expression (@pxref{Agent Expressions} | |
9264 | suitable for execution on the target, independently of @value{GDBN}. | |
9265 | Global variables become raw memory locations, locals become stack | |
9266 | accesses, and so forth. | |
9267 | ||
9268 | For instance, suppose you have a function that is usually called | |
9269 | frequently, but should not be called after an error has occurred. You | |
9270 | could use the following tracepoint command to collect data about calls | |
9271 | of that function that happen while the error code is propagating | |
9272 | through the program; an unconditional tracepoint could end up | |
9273 | collecting thousands of useless trace frames that you would have to | |
9274 | search through. | |
9275 | ||
9276 | @smallexample | |
9277 | (@value{GDBP}) @kbd{trace normal_operation if errcode > 0} | |
9278 | @end smallexample | |
9279 | ||
b37052ae EZ |
9280 | @node Tracepoint Actions |
9281 | @subsection Tracepoint Action Lists | |
9282 | ||
9283 | @table @code | |
9284 | @kindex actions | |
9285 | @cindex tracepoint actions | |
9286 | @item actions @r{[}@var{num}@r{]} | |
9287 | This command will prompt for a list of actions to be taken when the | |
9288 | tracepoint is hit. If the tracepoint number @var{num} is not | |
9289 | specified, this command sets the actions for the one that was most | |
9290 | recently defined (so that you can define a tracepoint and then say | |
9291 | @code{actions} without bothering about its number). You specify the | |
9292 | actions themselves on the following lines, one action at a time, and | |
9293 | terminate the actions list with a line containing just @code{end}. So | |
9294 | far, the only defined actions are @code{collect} and | |
9295 | @code{while-stepping}. | |
9296 | ||
9297 | @cindex remove actions from a tracepoint | |
9298 | To remove all actions from a tracepoint, type @samp{actions @var{num}} | |
9299 | and follow it immediately with @samp{end}. | |
9300 | ||
9301 | @smallexample | |
9302 | (@value{GDBP}) @b{collect @var{data}} // collect some data | |
9303 | ||
6826cf00 | 9304 | (@value{GDBP}) @b{while-stepping 5} // single-step 5 times, collect data |
b37052ae | 9305 | |
6826cf00 | 9306 | (@value{GDBP}) @b{end} // signals the end of actions. |
b37052ae EZ |
9307 | @end smallexample |
9308 | ||
9309 | In the following example, the action list begins with @code{collect} | |
9310 | commands indicating the things to be collected when the tracepoint is | |
9311 | hit. Then, in order to single-step and collect additional data | |
9312 | following the tracepoint, a @code{while-stepping} command is used, | |
9313 | followed by the list of things to be collected while stepping. The | |
9314 | @code{while-stepping} command is terminated by its own separate | |
9315 | @code{end} command. Lastly, the action list is terminated by an | |
9316 | @code{end} command. | |
9317 | ||
9318 | @smallexample | |
9319 | (@value{GDBP}) @b{trace foo} | |
9320 | (@value{GDBP}) @b{actions} | |
9321 | Enter actions for tracepoint 1, one per line: | |
9322 | > collect bar,baz | |
9323 | > collect $regs | |
9324 | > while-stepping 12 | |
9325 | > collect $fp, $sp | |
9326 | > end | |
9327 | end | |
9328 | @end smallexample | |
9329 | ||
9330 | @kindex collect @r{(tracepoints)} | |
9331 | @item collect @var{expr1}, @var{expr2}, @dots{} | |
9332 | Collect values of the given expressions when the tracepoint is hit. | |
9333 | This command accepts a comma-separated list of any valid expressions. | |
9334 | In addition to global, static, or local variables, the following | |
9335 | special arguments are supported: | |
9336 | ||
9337 | @table @code | |
9338 | @item $regs | |
9339 | collect all registers | |
9340 | ||
9341 | @item $args | |
9342 | collect all function arguments | |
9343 | ||
9344 | @item $locals | |
9345 | collect all local variables. | |
9346 | @end table | |
9347 | ||
9348 | You can give several consecutive @code{collect} commands, each one | |
9349 | with a single argument, or one @code{collect} command with several | |
9350 | arguments separated by commas: the effect is the same. | |
9351 | ||
f5c37c66 EZ |
9352 | The command @code{info scope} (@pxref{Symbols, info scope}) is |
9353 | particularly useful for figuring out what data to collect. | |
9354 | ||
b37052ae EZ |
9355 | @kindex while-stepping @r{(tracepoints)} |
9356 | @item while-stepping @var{n} | |
9357 | Perform @var{n} single-step traces after the tracepoint, collecting | |
9358 | new data at each step. The @code{while-stepping} command is | |
9359 | followed by the list of what to collect while stepping (followed by | |
9360 | its own @code{end} command): | |
9361 | ||
9362 | @smallexample | |
9363 | > while-stepping 12 | |
9364 | > collect $regs, myglobal | |
9365 | > end | |
9366 | > | |
9367 | @end smallexample | |
9368 | ||
9369 | @noindent | |
9370 | You may abbreviate @code{while-stepping} as @code{ws} or | |
9371 | @code{stepping}. | |
9372 | @end table | |
9373 | ||
9374 | @node Listing Tracepoints | |
9375 | @subsection Listing Tracepoints | |
9376 | ||
9377 | @table @code | |
9378 | @kindex info tracepoints | |
09d4efe1 | 9379 | @kindex info tp |
b37052ae EZ |
9380 | @cindex information about tracepoints |
9381 | @item info tracepoints @r{[}@var{num}@r{]} | |
1042e4c0 SS |
9382 | Display information about the tracepoint @var{num}. If you don't |
9383 | specify a tracepoint number, displays information about all the | |
9384 | tracepoints defined so far. The format is similar to that used for | |
9385 | @code{info breakpoints}; in fact, @code{info tracepoints} is the same | |
9386 | command, simply restricting itself to tracepoints. | |
9387 | ||
9388 | A tracepoint's listing may include additional information specific to | |
9389 | tracing: | |
b37052ae EZ |
9390 | |
9391 | @itemize @bullet | |
9392 | @item | |
b37052ae EZ |
9393 | its passcount as given by the @code{passcount @var{n}} command |
9394 | @item | |
9395 | its step count as given by the @code{while-stepping @var{n}} command | |
9396 | @item | |
1042e4c0 SS |
9397 | its action list as given by the @code{actions} command. The actions |
9398 | are prefixed with an @samp{A} so as to distinguish them from commands. | |
b37052ae EZ |
9399 | @end itemize |
9400 | ||
9401 | @smallexample | |
9402 | (@value{GDBP}) @b{info trace} | |
1042e4c0 SS |
9403 | Num Type Disp Enb Address What |
9404 | 1 tracepoint keep y 0x0804ab57 in foo() at main.cxx:7 | |
9405 | pass count 1200 | |
9406 | step count 20 | |
9407 | A while-stepping 20 | |
9408 | A collect globfoo, $regs | |
9409 | A end | |
9410 | A collect globfoo2 | |
9411 | A end | |
b37052ae EZ |
9412 | (@value{GDBP}) |
9413 | @end smallexample | |
9414 | ||
9415 | @noindent | |
9416 | This command can be abbreviated @code{info tp}. | |
9417 | @end table | |
9418 | ||
79a6e687 BW |
9419 | @node Starting and Stopping Trace Experiments |
9420 | @subsection Starting and Stopping Trace Experiments | |
b37052ae EZ |
9421 | |
9422 | @table @code | |
9423 | @kindex tstart | |
9424 | @cindex start a new trace experiment | |
9425 | @cindex collected data discarded | |
9426 | @item tstart | |
9427 | This command takes no arguments. It starts the trace experiment, and | |
9428 | begins collecting data. This has the side effect of discarding all | |
9429 | the data collected in the trace buffer during the previous trace | |
9430 | experiment. | |
9431 | ||
9432 | @kindex tstop | |
9433 | @cindex stop a running trace experiment | |
9434 | @item tstop | |
9435 | This command takes no arguments. It ends the trace experiment, and | |
9436 | stops collecting data. | |
9437 | ||
68c71a2e | 9438 | @strong{Note}: a trace experiment and data collection may stop |
b37052ae EZ |
9439 | automatically if any tracepoint's passcount is reached |
9440 | (@pxref{Tracepoint Passcounts}), or if the trace buffer becomes full. | |
9441 | ||
9442 | @kindex tstatus | |
9443 | @cindex status of trace data collection | |
9444 | @cindex trace experiment, status of | |
9445 | @item tstatus | |
9446 | This command displays the status of the current trace data | |
9447 | collection. | |
9448 | @end table | |
9449 | ||
9450 | Here is an example of the commands we described so far: | |
9451 | ||
9452 | @smallexample | |
9453 | (@value{GDBP}) @b{trace gdb_c_test} | |
9454 | (@value{GDBP}) @b{actions} | |
9455 | Enter actions for tracepoint #1, one per line. | |
9456 | > collect $regs,$locals,$args | |
9457 | > while-stepping 11 | |
9458 | > collect $regs | |
9459 | > end | |
9460 | > end | |
9461 | (@value{GDBP}) @b{tstart} | |
9462 | [time passes @dots{}] | |
9463 | (@value{GDBP}) @b{tstop} | |
9464 | @end smallexample | |
9465 | ||
9466 | ||
9467 | @node Analyze Collected Data | |
79a6e687 | 9468 | @section Using the Collected Data |
b37052ae EZ |
9469 | |
9470 | After the tracepoint experiment ends, you use @value{GDBN} commands | |
9471 | for examining the trace data. The basic idea is that each tracepoint | |
9472 | collects a trace @dfn{snapshot} every time it is hit and another | |
9473 | snapshot every time it single-steps. All these snapshots are | |
9474 | consecutively numbered from zero and go into a buffer, and you can | |
9475 | examine them later. The way you examine them is to @dfn{focus} on a | |
9476 | specific trace snapshot. When the remote stub is focused on a trace | |
9477 | snapshot, it will respond to all @value{GDBN} requests for memory and | |
9478 | registers by reading from the buffer which belongs to that snapshot, | |
9479 | rather than from @emph{real} memory or registers of the program being | |
9480 | debugged. This means that @strong{all} @value{GDBN} commands | |
9481 | (@code{print}, @code{info registers}, @code{backtrace}, etc.) will | |
9482 | behave as if we were currently debugging the program state as it was | |
9483 | when the tracepoint occurred. Any requests for data that are not in | |
9484 | the buffer will fail. | |
9485 | ||
9486 | @menu | |
9487 | * tfind:: How to select a trace snapshot | |
9488 | * tdump:: How to display all data for a snapshot | |
9489 | * save-tracepoints:: How to save tracepoints for a future run | |
9490 | @end menu | |
9491 | ||
9492 | @node tfind | |
9493 | @subsection @code{tfind @var{n}} | |
9494 | ||
9495 | @kindex tfind | |
9496 | @cindex select trace snapshot | |
9497 | @cindex find trace snapshot | |
9498 | The basic command for selecting a trace snapshot from the buffer is | |
9499 | @code{tfind @var{n}}, which finds trace snapshot number @var{n}, | |
9500 | counting from zero. If no argument @var{n} is given, the next | |
9501 | snapshot is selected. | |
9502 | ||
9503 | Here are the various forms of using the @code{tfind} command. | |
9504 | ||
9505 | @table @code | |
9506 | @item tfind start | |
9507 | Find the first snapshot in the buffer. This is a synonym for | |
9508 | @code{tfind 0} (since 0 is the number of the first snapshot). | |
9509 | ||
9510 | @item tfind none | |
9511 | Stop debugging trace snapshots, resume @emph{live} debugging. | |
9512 | ||
9513 | @item tfind end | |
9514 | Same as @samp{tfind none}. | |
9515 | ||
9516 | @item tfind | |
9517 | No argument means find the next trace snapshot. | |
9518 | ||
9519 | @item tfind - | |
9520 | Find the previous trace snapshot before the current one. This permits | |
9521 | retracing earlier steps. | |
9522 | ||
9523 | @item tfind tracepoint @var{num} | |
9524 | Find the next snapshot associated with tracepoint @var{num}. Search | |
9525 | proceeds forward from the last examined trace snapshot. If no | |
9526 | argument @var{num} is given, it means find the next snapshot collected | |
9527 | for the same tracepoint as the current snapshot. | |
9528 | ||
9529 | @item tfind pc @var{addr} | |
9530 | Find the next snapshot associated with the value @var{addr} of the | |
9531 | program counter. Search proceeds forward from the last examined trace | |
9532 | snapshot. If no argument @var{addr} is given, it means find the next | |
9533 | snapshot with the same value of PC as the current snapshot. | |
9534 | ||
9535 | @item tfind outside @var{addr1}, @var{addr2} | |
9536 | Find the next snapshot whose PC is outside the given range of | |
9537 | addresses. | |
9538 | ||
9539 | @item tfind range @var{addr1}, @var{addr2} | |
9540 | Find the next snapshot whose PC is between @var{addr1} and | |
9541 | @var{addr2}. @c FIXME: Is the range inclusive or exclusive? | |
9542 | ||
9543 | @item tfind line @r{[}@var{file}:@r{]}@var{n} | |
9544 | Find the next snapshot associated with the source line @var{n}. If | |
9545 | the optional argument @var{file} is given, refer to line @var{n} in | |
9546 | that source file. Search proceeds forward from the last examined | |
9547 | trace snapshot. If no argument @var{n} is given, it means find the | |
9548 | next line other than the one currently being examined; thus saying | |
9549 | @code{tfind line} repeatedly can appear to have the same effect as | |
9550 | stepping from line to line in a @emph{live} debugging session. | |
9551 | @end table | |
9552 | ||
9553 | The default arguments for the @code{tfind} commands are specifically | |
9554 | designed to make it easy to scan through the trace buffer. For | |
9555 | instance, @code{tfind} with no argument selects the next trace | |
9556 | snapshot, and @code{tfind -} with no argument selects the previous | |
9557 | trace snapshot. So, by giving one @code{tfind} command, and then | |
9558 | simply hitting @key{RET} repeatedly you can examine all the trace | |
9559 | snapshots in order. Or, by saying @code{tfind -} and then hitting | |
9560 | @key{RET} repeatedly you can examine the snapshots in reverse order. | |
9561 | The @code{tfind line} command with no argument selects the snapshot | |
9562 | for the next source line executed. The @code{tfind pc} command with | |
9563 | no argument selects the next snapshot with the same program counter | |
9564 | (PC) as the current frame. The @code{tfind tracepoint} command with | |
9565 | no argument selects the next trace snapshot collected by the same | |
9566 | tracepoint as the current one. | |
9567 | ||
9568 | In addition to letting you scan through the trace buffer manually, | |
9569 | these commands make it easy to construct @value{GDBN} scripts that | |
9570 | scan through the trace buffer and print out whatever collected data | |
9571 | you are interested in. Thus, if we want to examine the PC, FP, and SP | |
9572 | registers from each trace frame in the buffer, we can say this: | |
9573 | ||
9574 | @smallexample | |
9575 | (@value{GDBP}) @b{tfind start} | |
9576 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
9577 | > printf "Frame %d, PC = %08X, SP = %08X, FP = %08X\n", \ | |
9578 | $trace_frame, $pc, $sp, $fp | |
9579 | > tfind | |
9580 | > end | |
9581 | ||
9582 | Frame 0, PC = 0020DC64, SP = 0030BF3C, FP = 0030BF44 | |
9583 | Frame 1, PC = 0020DC6C, SP = 0030BF38, FP = 0030BF44 | |
9584 | Frame 2, PC = 0020DC70, SP = 0030BF34, FP = 0030BF44 | |
9585 | Frame 3, PC = 0020DC74, SP = 0030BF30, FP = 0030BF44 | |
9586 | Frame 4, PC = 0020DC78, SP = 0030BF2C, FP = 0030BF44 | |
9587 | Frame 5, PC = 0020DC7C, SP = 0030BF28, FP = 0030BF44 | |
9588 | Frame 6, PC = 0020DC80, SP = 0030BF24, FP = 0030BF44 | |
9589 | Frame 7, PC = 0020DC84, SP = 0030BF20, FP = 0030BF44 | |
9590 | Frame 8, PC = 0020DC88, SP = 0030BF1C, FP = 0030BF44 | |
9591 | Frame 9, PC = 0020DC8E, SP = 0030BF18, FP = 0030BF44 | |
9592 | Frame 10, PC = 00203F6C, SP = 0030BE3C, FP = 0030BF14 | |
9593 | @end smallexample | |
9594 | ||
9595 | Or, if we want to examine the variable @code{X} at each source line in | |
9596 | the buffer: | |
9597 | ||
9598 | @smallexample | |
9599 | (@value{GDBP}) @b{tfind start} | |
9600 | (@value{GDBP}) @b{while ($trace_frame != -1)} | |
9601 | > printf "Frame %d, X == %d\n", $trace_frame, X | |
9602 | > tfind line | |
9603 | > end | |
9604 | ||
9605 | Frame 0, X = 1 | |
9606 | Frame 7, X = 2 | |
9607 | Frame 13, X = 255 | |
9608 | @end smallexample | |
9609 | ||
9610 | @node tdump | |
9611 | @subsection @code{tdump} | |
9612 | @kindex tdump | |
9613 | @cindex dump all data collected at tracepoint | |
9614 | @cindex tracepoint data, display | |
9615 | ||
9616 | This command takes no arguments. It prints all the data collected at | |
9617 | the current trace snapshot. | |
9618 | ||
9619 | @smallexample | |
9620 | (@value{GDBP}) @b{trace 444} | |
9621 | (@value{GDBP}) @b{actions} | |
9622 | Enter actions for tracepoint #2, one per line: | |
9623 | > collect $regs, $locals, $args, gdb_long_test | |
9624 | > end | |
9625 | ||
9626 | (@value{GDBP}) @b{tstart} | |
9627 | ||
9628 | (@value{GDBP}) @b{tfind line 444} | |
9629 | #0 gdb_test (p1=0x11, p2=0x22, p3=0x33, p4=0x44, p5=0x55, p6=0x66) | |
9630 | at gdb_test.c:444 | |
9631 | 444 printp( "%s: arguments = 0x%X 0x%X 0x%X 0x%X 0x%X 0x%X\n", ) | |
9632 | ||
9633 | (@value{GDBP}) @b{tdump} | |
9634 | Data collected at tracepoint 2, trace frame 1: | |
9635 | d0 0xc4aa0085 -995491707 | |
9636 | d1 0x18 24 | |
9637 | d2 0x80 128 | |
9638 | d3 0x33 51 | |
9639 | d4 0x71aea3d 119204413 | |
9640 | d5 0x22 34 | |
9641 | d6 0xe0 224 | |
9642 | d7 0x380035 3670069 | |
9643 | a0 0x19e24a 1696330 | |
9644 | a1 0x3000668 50333288 | |
9645 | a2 0x100 256 | |
9646 | a3 0x322000 3284992 | |
9647 | a4 0x3000698 50333336 | |
9648 | a5 0x1ad3cc 1758156 | |
9649 | fp 0x30bf3c 0x30bf3c | |
9650 | sp 0x30bf34 0x30bf34 | |
9651 | ps 0x0 0 | |
9652 | pc 0x20b2c8 0x20b2c8 | |
9653 | fpcontrol 0x0 0 | |
9654 | fpstatus 0x0 0 | |
9655 | fpiaddr 0x0 0 | |
9656 | p = 0x20e5b4 "gdb-test" | |
9657 | p1 = (void *) 0x11 | |
9658 | p2 = (void *) 0x22 | |
9659 | p3 = (void *) 0x33 | |
9660 | p4 = (void *) 0x44 | |
9661 | p5 = (void *) 0x55 | |
9662 | p6 = (void *) 0x66 | |
9663 | gdb_long_test = 17 '\021' | |
9664 | ||
9665 | (@value{GDBP}) | |
9666 | @end smallexample | |
9667 | ||
9668 | @node save-tracepoints | |
9669 | @subsection @code{save-tracepoints @var{filename}} | |
9670 | @kindex save-tracepoints | |
9671 | @cindex save tracepoints for future sessions | |
9672 | ||
9673 | This command saves all current tracepoint definitions together with | |
9674 | their actions and passcounts, into a file @file{@var{filename}} | |
9675 | suitable for use in a later debugging session. To read the saved | |
9676 | tracepoint definitions, use the @code{source} command (@pxref{Command | |
9677 | Files}). | |
9678 | ||
9679 | @node Tracepoint Variables | |
9680 | @section Convenience Variables for Tracepoints | |
9681 | @cindex tracepoint variables | |
9682 | @cindex convenience variables for tracepoints | |
9683 | ||
9684 | @table @code | |
9685 | @vindex $trace_frame | |
9686 | @item (int) $trace_frame | |
9687 | The current trace snapshot (a.k.a.@: @dfn{frame}) number, or -1 if no | |
9688 | snapshot is selected. | |
9689 | ||
9690 | @vindex $tracepoint | |
9691 | @item (int) $tracepoint | |
9692 | The tracepoint for the current trace snapshot. | |
9693 | ||
9694 | @vindex $trace_line | |
9695 | @item (int) $trace_line | |
9696 | The line number for the current trace snapshot. | |
9697 | ||
9698 | @vindex $trace_file | |
9699 | @item (char []) $trace_file | |
9700 | The source file for the current trace snapshot. | |
9701 | ||
9702 | @vindex $trace_func | |
9703 | @item (char []) $trace_func | |
9704 | The name of the function containing @code{$tracepoint}. | |
9705 | @end table | |
9706 | ||
9707 | Note: @code{$trace_file} is not suitable for use in @code{printf}, | |
9708 | use @code{output} instead. | |
9709 | ||
9710 | Here's a simple example of using these convenience variables for | |
9711 | stepping through all the trace snapshots and printing some of their | |
9712 | data. | |
9713 | ||
9714 | @smallexample | |
9715 | (@value{GDBP}) @b{tfind start} | |
9716 | ||
9717 | (@value{GDBP}) @b{while $trace_frame != -1} | |
9718 | > output $trace_file | |
9719 | > printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint | |
9720 | > tfind | |
9721 | > end | |
9722 | @end smallexample | |
9723 | ||
df0cd8c5 JB |
9724 | @node Overlays |
9725 | @chapter Debugging Programs That Use Overlays | |
9726 | @cindex overlays | |
9727 | ||
9728 | If your program is too large to fit completely in your target system's | |
9729 | memory, you can sometimes use @dfn{overlays} to work around this | |
9730 | problem. @value{GDBN} provides some support for debugging programs that | |
9731 | use overlays. | |
9732 | ||
9733 | @menu | |
9734 | * How Overlays Work:: A general explanation of overlays. | |
9735 | * Overlay Commands:: Managing overlays in @value{GDBN}. | |
9736 | * Automatic Overlay Debugging:: @value{GDBN} can find out which overlays are | |
9737 | mapped by asking the inferior. | |
9738 | * Overlay Sample Program:: A sample program using overlays. | |
9739 | @end menu | |
9740 | ||
9741 | @node How Overlays Work | |
9742 | @section How Overlays Work | |
9743 | @cindex mapped overlays | |
9744 | @cindex unmapped overlays | |
9745 | @cindex load address, overlay's | |
9746 | @cindex mapped address | |
9747 | @cindex overlay area | |
9748 | ||
9749 | Suppose you have a computer whose instruction address space is only 64 | |
9750 | kilobytes long, but which has much more memory which can be accessed by | |
9751 | other means: special instructions, segment registers, or memory | |
9752 | management hardware, for example. Suppose further that you want to | |
9753 | adapt a program which is larger than 64 kilobytes to run on this system. | |
9754 | ||
9755 | One solution is to identify modules of your program which are relatively | |
9756 | independent, and need not call each other directly; call these modules | |
9757 | @dfn{overlays}. Separate the overlays from the main program, and place | |
9758 | their machine code in the larger memory. Place your main program in | |
9759 | instruction memory, but leave at least enough space there to hold the | |
9760 | largest overlay as well. | |
9761 | ||
9762 | Now, to call a function located in an overlay, you must first copy that | |
9763 | overlay's machine code from the large memory into the space set aside | |
9764 | for it in the instruction memory, and then jump to its entry point | |
9765 | there. | |
9766 | ||
c928edc0 AC |
9767 | @c NB: In the below the mapped area's size is greater or equal to the |
9768 | @c size of all overlays. This is intentional to remind the developer | |
9769 | @c that overlays don't necessarily need to be the same size. | |
9770 | ||
474c8240 | 9771 | @smallexample |
df0cd8c5 | 9772 | @group |
c928edc0 AC |
9773 | Data Instruction Larger |
9774 | Address Space Address Space Address Space | |
9775 | +-----------+ +-----------+ +-----------+ | |
9776 | | | | | | | | |
9777 | +-----------+ +-----------+ +-----------+<-- overlay 1 | |
9778 | | program | | main | .----| overlay 1 | load address | |
9779 | | variables | | program | | +-----------+ | |
9780 | | and heap | | | | | | | |
9781 | +-----------+ | | | +-----------+<-- overlay 2 | |
9782 | | | +-----------+ | | | load address | |
9783 | +-----------+ | | | .-| overlay 2 | | |
9784 | | | | | | | | |
9785 | mapped --->+-----------+ | | +-----------+ | |
9786 | address | | | | | | | |
9787 | | overlay | <-' | | | | |
9788 | | area | <---' +-----------+<-- overlay 3 | |
9789 | | | <---. | | load address | |
9790 | +-----------+ `--| overlay 3 | | |
9791 | | | | | | |
9792 | +-----------+ | | | |
9793 | +-----------+ | |
9794 | | | | |
9795 | +-----------+ | |
9796 | ||
9797 | @anchor{A code overlay}A code overlay | |
df0cd8c5 | 9798 | @end group |
474c8240 | 9799 | @end smallexample |
df0cd8c5 | 9800 | |
c928edc0 AC |
9801 | The diagram (@pxref{A code overlay}) shows a system with separate data |
9802 | and instruction address spaces. To map an overlay, the program copies | |
9803 | its code from the larger address space to the instruction address space. | |
9804 | Since the overlays shown here all use the same mapped address, only one | |
9805 | may be mapped at a time. For a system with a single address space for | |
9806 | data and instructions, the diagram would be similar, except that the | |
9807 | program variables and heap would share an address space with the main | |
9808 | program and the overlay area. | |
df0cd8c5 JB |
9809 | |
9810 | An overlay loaded into instruction memory and ready for use is called a | |
9811 | @dfn{mapped} overlay; its @dfn{mapped address} is its address in the | |
9812 | instruction memory. An overlay not present (or only partially present) | |
9813 | in instruction memory is called @dfn{unmapped}; its @dfn{load address} | |
9814 | is its address in the larger memory. The mapped address is also called | |
9815 | the @dfn{virtual memory address}, or @dfn{VMA}; the load address is also | |
9816 | called the @dfn{load memory address}, or @dfn{LMA}. | |
9817 | ||
9818 | Unfortunately, overlays are not a completely transparent way to adapt a | |
9819 | program to limited instruction memory. They introduce a new set of | |
9820 | global constraints you must keep in mind as you design your program: | |
9821 | ||
9822 | @itemize @bullet | |
9823 | ||
9824 | @item | |
9825 | Before calling or returning to a function in an overlay, your program | |
9826 | must make sure that overlay is actually mapped. Otherwise, the call or | |
9827 | return will transfer control to the right address, but in the wrong | |
9828 | overlay, and your program will probably crash. | |
9829 | ||
9830 | @item | |
9831 | If the process of mapping an overlay is expensive on your system, you | |
9832 | will need to choose your overlays carefully to minimize their effect on | |
9833 | your program's performance. | |
9834 | ||
9835 | @item | |
9836 | The executable file you load onto your system must contain each | |
9837 | overlay's instructions, appearing at the overlay's load address, not its | |
9838 | mapped address. However, each overlay's instructions must be relocated | |
9839 | and its symbols defined as if the overlay were at its mapped address. | |
9840 | You can use GNU linker scripts to specify different load and relocation | |
9841 | addresses for pieces of your program; see @ref{Overlay Description,,, | |
9842 | ld.info, Using ld: the GNU linker}. | |
9843 | ||
9844 | @item | |
9845 | The procedure for loading executable files onto your system must be able | |
9846 | to load their contents into the larger address space as well as the | |
9847 | instruction and data spaces. | |
9848 | ||
9849 | @end itemize | |
9850 | ||
9851 | The overlay system described above is rather simple, and could be | |
9852 | improved in many ways: | |
9853 | ||
9854 | @itemize @bullet | |
9855 | ||
9856 | @item | |
9857 | If your system has suitable bank switch registers or memory management | |
9858 | hardware, you could use those facilities to make an overlay's load area | |
9859 | contents simply appear at their mapped address in instruction space. | |
9860 | This would probably be faster than copying the overlay to its mapped | |
9861 | area in the usual way. | |
9862 | ||
9863 | @item | |
9864 | If your overlays are small enough, you could set aside more than one | |
9865 | overlay area, and have more than one overlay mapped at a time. | |
9866 | ||
9867 | @item | |
9868 | You can use overlays to manage data, as well as instructions. In | |
9869 | general, data overlays are even less transparent to your design than | |
9870 | code overlays: whereas code overlays only require care when you call or | |
9871 | return to functions, data overlays require care every time you access | |
9872 | the data. Also, if you change the contents of a data overlay, you | |
9873 | must copy its contents back out to its load address before you can copy a | |
9874 | different data overlay into the same mapped area. | |
9875 | ||
9876 | @end itemize | |
9877 | ||
9878 | ||
9879 | @node Overlay Commands | |
9880 | @section Overlay Commands | |
9881 | ||
9882 | To use @value{GDBN}'s overlay support, each overlay in your program must | |
9883 | correspond to a separate section of the executable file. The section's | |
9884 | virtual memory address and load memory address must be the overlay's | |
9885 | mapped and load addresses. Identifying overlays with sections allows | |
9886 | @value{GDBN} to determine the appropriate address of a function or | |
9887 | variable, depending on whether the overlay is mapped or not. | |
9888 | ||
9889 | @value{GDBN}'s overlay commands all start with the word @code{overlay}; | |
9890 | you can abbreviate this as @code{ov} or @code{ovly}. The commands are: | |
9891 | ||
9892 | @table @code | |
9893 | @item overlay off | |
4644b6e3 | 9894 | @kindex overlay |
df0cd8c5 JB |
9895 | Disable @value{GDBN}'s overlay support. When overlay support is |
9896 | disabled, @value{GDBN} assumes that all functions and variables are | |
9897 | always present at their mapped addresses. By default, @value{GDBN}'s | |
9898 | overlay support is disabled. | |
9899 | ||
9900 | @item overlay manual | |
df0cd8c5 JB |
9901 | @cindex manual overlay debugging |
9902 | Enable @dfn{manual} overlay debugging. In this mode, @value{GDBN} | |
9903 | relies on you to tell it which overlays are mapped, and which are not, | |
9904 | using the @code{overlay map-overlay} and @code{overlay unmap-overlay} | |
9905 | commands described below. | |
9906 | ||
9907 | @item overlay map-overlay @var{overlay} | |
9908 | @itemx overlay map @var{overlay} | |
df0cd8c5 JB |
9909 | @cindex map an overlay |
9910 | Tell @value{GDBN} that @var{overlay} is now mapped; @var{overlay} must | |
9911 | be the name of the object file section containing the overlay. When an | |
9912 | overlay is mapped, @value{GDBN} assumes it can find the overlay's | |
9913 | functions and variables at their mapped addresses. @value{GDBN} assumes | |
9914 | that any other overlays whose mapped ranges overlap that of | |
9915 | @var{overlay} are now unmapped. | |
9916 | ||
9917 | @item overlay unmap-overlay @var{overlay} | |
9918 | @itemx overlay unmap @var{overlay} | |
df0cd8c5 JB |
9919 | @cindex unmap an overlay |
9920 | Tell @value{GDBN} that @var{overlay} is no longer mapped; @var{overlay} | |
9921 | must be the name of the object file section containing the overlay. | |
9922 | When an overlay is unmapped, @value{GDBN} assumes it can find the | |
9923 | overlay's functions and variables at their load addresses. | |
9924 | ||
9925 | @item overlay auto | |
df0cd8c5 JB |
9926 | Enable @dfn{automatic} overlay debugging. In this mode, @value{GDBN} |
9927 | consults a data structure the overlay manager maintains in the inferior | |
9928 | to see which overlays are mapped. For details, see @ref{Automatic | |
9929 | Overlay Debugging}. | |
9930 | ||
9931 | @item overlay load-target | |
9932 | @itemx overlay load | |
df0cd8c5 JB |
9933 | @cindex reloading the overlay table |
9934 | Re-read the overlay table from the inferior. Normally, @value{GDBN} | |
9935 | re-reads the table @value{GDBN} automatically each time the inferior | |
9936 | stops, so this command should only be necessary if you have changed the | |
9937 | overlay mapping yourself using @value{GDBN}. This command is only | |
9938 | useful when using automatic overlay debugging. | |
9939 | ||
9940 | @item overlay list-overlays | |
9941 | @itemx overlay list | |
9942 | @cindex listing mapped overlays | |
9943 | Display a list of the overlays currently mapped, along with their mapped | |
9944 | addresses, load addresses, and sizes. | |
9945 | ||
9946 | @end table | |
9947 | ||
9948 | Normally, when @value{GDBN} prints a code address, it includes the name | |
9949 | of the function the address falls in: | |
9950 | ||
474c8240 | 9951 | @smallexample |
f7dc1244 | 9952 | (@value{GDBP}) print main |
df0cd8c5 | 9953 | $3 = @{int ()@} 0x11a0 <main> |
474c8240 | 9954 | @end smallexample |
df0cd8c5 JB |
9955 | @noindent |
9956 | When overlay debugging is enabled, @value{GDBN} recognizes code in | |
9957 | unmapped overlays, and prints the names of unmapped functions with | |
9958 | asterisks around them. For example, if @code{foo} is a function in an | |
9959 | unmapped overlay, @value{GDBN} prints it this way: | |
9960 | ||
474c8240 | 9961 | @smallexample |
f7dc1244 | 9962 | (@value{GDBP}) overlay list |
df0cd8c5 | 9963 | No sections are mapped. |
f7dc1244 | 9964 | (@value{GDBP}) print foo |
df0cd8c5 | 9965 | $5 = @{int (int)@} 0x100000 <*foo*> |
474c8240 | 9966 | @end smallexample |
df0cd8c5 JB |
9967 | @noindent |
9968 | When @code{foo}'s overlay is mapped, @value{GDBN} prints the function's | |
9969 | name normally: | |
9970 | ||
474c8240 | 9971 | @smallexample |
f7dc1244 | 9972 | (@value{GDBP}) overlay list |
b383017d | 9973 | Section .ov.foo.text, loaded at 0x100000 - 0x100034, |
df0cd8c5 | 9974 | mapped at 0x1016 - 0x104a |
f7dc1244 | 9975 | (@value{GDBP}) print foo |
df0cd8c5 | 9976 | $6 = @{int (int)@} 0x1016 <foo> |
474c8240 | 9977 | @end smallexample |
df0cd8c5 JB |
9978 | |
9979 | When overlay debugging is enabled, @value{GDBN} can find the correct | |
9980 | address for functions and variables in an overlay, whether or not the | |
9981 | overlay is mapped. This allows most @value{GDBN} commands, like | |
9982 | @code{break} and @code{disassemble}, to work normally, even on unmapped | |
9983 | code. However, @value{GDBN}'s breakpoint support has some limitations: | |
9984 | ||
9985 | @itemize @bullet | |
9986 | @item | |
9987 | @cindex breakpoints in overlays | |
9988 | @cindex overlays, setting breakpoints in | |
9989 | You can set breakpoints in functions in unmapped overlays, as long as | |
9990 | @value{GDBN} can write to the overlay at its load address. | |
9991 | @item | |
9992 | @value{GDBN} can not set hardware or simulator-based breakpoints in | |
9993 | unmapped overlays. However, if you set a breakpoint at the end of your | |
9994 | overlay manager (and tell @value{GDBN} which overlays are now mapped, if | |
9995 | you are using manual overlay management), @value{GDBN} will re-set its | |
9996 | breakpoints properly. | |
9997 | @end itemize | |
9998 | ||
9999 | ||
10000 | @node Automatic Overlay Debugging | |
10001 | @section Automatic Overlay Debugging | |
10002 | @cindex automatic overlay debugging | |
10003 | ||
10004 | @value{GDBN} can automatically track which overlays are mapped and which | |
10005 | are not, given some simple co-operation from the overlay manager in the | |
10006 | inferior. If you enable automatic overlay debugging with the | |
10007 | @code{overlay auto} command (@pxref{Overlay Commands}), @value{GDBN} | |
10008 | looks in the inferior's memory for certain variables describing the | |
10009 | current state of the overlays. | |
10010 | ||
10011 | Here are the variables your overlay manager must define to support | |
10012 | @value{GDBN}'s automatic overlay debugging: | |
10013 | ||
10014 | @table @asis | |
10015 | ||
10016 | @item @code{_ovly_table}: | |
10017 | This variable must be an array of the following structures: | |
10018 | ||
474c8240 | 10019 | @smallexample |
df0cd8c5 JB |
10020 | struct |
10021 | @{ | |
10022 | /* The overlay's mapped address. */ | |
10023 | unsigned long vma; | |
10024 | ||
10025 | /* The size of the overlay, in bytes. */ | |
10026 | unsigned long size; | |
10027 | ||
10028 | /* The overlay's load address. */ | |
10029 | unsigned long lma; | |
10030 | ||
10031 | /* Non-zero if the overlay is currently mapped; | |
10032 | zero otherwise. */ | |
10033 | unsigned long mapped; | |
10034 | @} | |
474c8240 | 10035 | @end smallexample |
df0cd8c5 JB |
10036 | |
10037 | @item @code{_novlys}: | |
10038 | This variable must be a four-byte signed integer, holding the total | |
10039 | number of elements in @code{_ovly_table}. | |
10040 | ||
10041 | @end table | |
10042 | ||
10043 | To decide whether a particular overlay is mapped or not, @value{GDBN} | |
10044 | looks for an entry in @w{@code{_ovly_table}} whose @code{vma} and | |
10045 | @code{lma} members equal the VMA and LMA of the overlay's section in the | |
10046 | executable file. When @value{GDBN} finds a matching entry, it consults | |
10047 | the entry's @code{mapped} member to determine whether the overlay is | |
10048 | currently mapped. | |
10049 | ||
81d46470 | 10050 | In addition, your overlay manager may define a function called |
def71bfa | 10051 | @code{_ovly_debug_event}. If this function is defined, @value{GDBN} |
81d46470 MS |
10052 | will silently set a breakpoint there. If the overlay manager then |
10053 | calls this function whenever it has changed the overlay table, this | |
10054 | will enable @value{GDBN} to accurately keep track of which overlays | |
10055 | are in program memory, and update any breakpoints that may be set | |
b383017d | 10056 | in overlays. This will allow breakpoints to work even if the |
81d46470 MS |
10057 | overlays are kept in ROM or other non-writable memory while they |
10058 | are not being executed. | |
df0cd8c5 JB |
10059 | |
10060 | @node Overlay Sample Program | |
10061 | @section Overlay Sample Program | |
10062 | @cindex overlay example program | |
10063 | ||
10064 | When linking a program which uses overlays, you must place the overlays | |
10065 | at their load addresses, while relocating them to run at their mapped | |
10066 | addresses. To do this, you must write a linker script (@pxref{Overlay | |
10067 | Description,,, ld.info, Using ld: the GNU linker}). Unfortunately, | |
10068 | since linker scripts are specific to a particular host system, target | |
10069 | architecture, and target memory layout, this manual cannot provide | |
10070 | portable sample code demonstrating @value{GDBN}'s overlay support. | |
10071 | ||
10072 | However, the @value{GDBN} source distribution does contain an overlaid | |
10073 | program, with linker scripts for a few systems, as part of its test | |
10074 | suite. The program consists of the following files from | |
10075 | @file{gdb/testsuite/gdb.base}: | |
10076 | ||
10077 | @table @file | |
10078 | @item overlays.c | |
10079 | The main program file. | |
10080 | @item ovlymgr.c | |
10081 | A simple overlay manager, used by @file{overlays.c}. | |
10082 | @item foo.c | |
10083 | @itemx bar.c | |
10084 | @itemx baz.c | |
10085 | @itemx grbx.c | |
10086 | Overlay modules, loaded and used by @file{overlays.c}. | |
10087 | @item d10v.ld | |
10088 | @itemx m32r.ld | |
10089 | Linker scripts for linking the test program on the @code{d10v-elf} | |
10090 | and @code{m32r-elf} targets. | |
10091 | @end table | |
10092 | ||
10093 | You can build the test program using the @code{d10v-elf} GCC | |
10094 | cross-compiler like this: | |
10095 | ||
474c8240 | 10096 | @smallexample |
df0cd8c5 JB |
10097 | $ d10v-elf-gcc -g -c overlays.c |
10098 | $ d10v-elf-gcc -g -c ovlymgr.c | |
10099 | $ d10v-elf-gcc -g -c foo.c | |
10100 | $ d10v-elf-gcc -g -c bar.c | |
10101 | $ d10v-elf-gcc -g -c baz.c | |
10102 | $ d10v-elf-gcc -g -c grbx.c | |
10103 | $ d10v-elf-gcc -g overlays.o ovlymgr.o foo.o bar.o \ | |
10104 | baz.o grbx.o -Wl,-Td10v.ld -o overlays | |
474c8240 | 10105 | @end smallexample |
df0cd8c5 JB |
10106 | |
10107 | The build process is identical for any other architecture, except that | |
10108 | you must substitute the appropriate compiler and linker script for the | |
10109 | target system for @code{d10v-elf-gcc} and @code{d10v.ld}. | |
10110 | ||
10111 | ||
6d2ebf8b | 10112 | @node Languages |
c906108c SS |
10113 | @chapter Using @value{GDBN} with Different Languages |
10114 | @cindex languages | |
10115 | ||
c906108c SS |
10116 | Although programming languages generally have common aspects, they are |
10117 | rarely expressed in the same manner. For instance, in ANSI C, | |
10118 | dereferencing a pointer @code{p} is accomplished by @code{*p}, but in | |
10119 | Modula-2, it is accomplished by @code{p^}. Values can also be | |
5d161b24 | 10120 | represented (and displayed) differently. Hex numbers in C appear as |
c906108c | 10121 | @samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}. |
c906108c SS |
10122 | |
10123 | @cindex working language | |
10124 | Language-specific information is built into @value{GDBN} for some languages, | |
10125 | allowing you to express operations like the above in your program's | |
10126 | native language, and allowing @value{GDBN} to output values in a manner | |
10127 | consistent with the syntax of your program's native language. The | |
10128 | language you use to build expressions is called the @dfn{working | |
10129 | language}. | |
10130 | ||
10131 | @menu | |
10132 | * Setting:: Switching between source languages | |
10133 | * Show:: Displaying the language | |
c906108c | 10134 | * Checks:: Type and range checks |
79a6e687 BW |
10135 | * Supported Languages:: Supported languages |
10136 | * Unsupported Languages:: Unsupported languages | |
c906108c SS |
10137 | @end menu |
10138 | ||
6d2ebf8b | 10139 | @node Setting |
79a6e687 | 10140 | @section Switching Between Source Languages |
c906108c SS |
10141 | |
10142 | There are two ways to control the working language---either have @value{GDBN} | |
10143 | set it automatically, or select it manually yourself. You can use the | |
10144 | @code{set language} command for either purpose. On startup, @value{GDBN} | |
10145 | defaults to setting the language automatically. The working language is | |
10146 | used to determine how expressions you type are interpreted, how values | |
10147 | are printed, etc. | |
10148 | ||
10149 | In addition to the working language, every source file that | |
10150 | @value{GDBN} knows about has its own working language. For some object | |
10151 | file formats, the compiler might indicate which language a particular | |
10152 | source file is in. However, most of the time @value{GDBN} infers the | |
10153 | language from the name of the file. The language of a source file | |
b37052ae | 10154 | controls whether C@t{++} names are demangled---this way @code{backtrace} can |
c906108c | 10155 | show each frame appropriately for its own language. There is no way to |
d4f3574e SS |
10156 | set the language of a source file from within @value{GDBN}, but you can |
10157 | set the language associated with a filename extension. @xref{Show, , | |
79a6e687 | 10158 | Displaying the Language}. |
c906108c SS |
10159 | |
10160 | This is most commonly a problem when you use a program, such | |
5d161b24 | 10161 | as @code{cfront} or @code{f2c}, that generates C but is written in |
c906108c SS |
10162 | another language. In that case, make the |
10163 | program use @code{#line} directives in its C output; that way | |
10164 | @value{GDBN} will know the correct language of the source code of the original | |
10165 | program, and will display that source code, not the generated C code. | |
10166 | ||
10167 | @menu | |
10168 | * Filenames:: Filename extensions and languages. | |
10169 | * Manually:: Setting the working language manually | |
10170 | * Automatically:: Having @value{GDBN} infer the source language | |
10171 | @end menu | |
10172 | ||
6d2ebf8b | 10173 | @node Filenames |
79a6e687 | 10174 | @subsection List of Filename Extensions and Languages |
c906108c SS |
10175 | |
10176 | If a source file name ends in one of the following extensions, then | |
10177 | @value{GDBN} infers that its language is the one indicated. | |
10178 | ||
10179 | @table @file | |
e07c999f PH |
10180 | @item .ada |
10181 | @itemx .ads | |
10182 | @itemx .adb | |
10183 | @itemx .a | |
10184 | Ada source file. | |
c906108c SS |
10185 | |
10186 | @item .c | |
10187 | C source file | |
10188 | ||
10189 | @item .C | |
10190 | @itemx .cc | |
10191 | @itemx .cp | |
10192 | @itemx .cpp | |
10193 | @itemx .cxx | |
10194 | @itemx .c++ | |
b37052ae | 10195 | C@t{++} source file |
c906108c | 10196 | |
b37303ee AF |
10197 | @item .m |
10198 | Objective-C source file | |
10199 | ||
c906108c SS |
10200 | @item .f |
10201 | @itemx .F | |
10202 | Fortran source file | |
10203 | ||
c906108c SS |
10204 | @item .mod |
10205 | Modula-2 source file | |
c906108c SS |
10206 | |
10207 | @item .s | |
10208 | @itemx .S | |
10209 | Assembler source file. This actually behaves almost like C, but | |
10210 | @value{GDBN} does not skip over function prologues when stepping. | |
10211 | @end table | |
10212 | ||
10213 | In addition, you may set the language associated with a filename | |
79a6e687 | 10214 | extension. @xref{Show, , Displaying the Language}. |
c906108c | 10215 | |
6d2ebf8b | 10216 | @node Manually |
79a6e687 | 10217 | @subsection Setting the Working Language |
c906108c SS |
10218 | |
10219 | If you allow @value{GDBN} to set the language automatically, | |
10220 | expressions are interpreted the same way in your debugging session and | |
10221 | your program. | |
10222 | ||
10223 | @kindex set language | |
10224 | If you wish, you may set the language manually. To do this, issue the | |
10225 | command @samp{set language @var{lang}}, where @var{lang} is the name of | |
5d161b24 | 10226 | a language, such as |
c906108c | 10227 | @code{c} or @code{modula-2}. |
c906108c SS |
10228 | For a list of the supported languages, type @samp{set language}. |
10229 | ||
c906108c SS |
10230 | Setting the language manually prevents @value{GDBN} from updating the working |
10231 | language automatically. This can lead to confusion if you try | |
10232 | to debug a program when the working language is not the same as the | |
10233 | source language, when an expression is acceptable to both | |
10234 | languages---but means different things. For instance, if the current | |
10235 | source file were written in C, and @value{GDBN} was parsing Modula-2, a | |
10236 | command such as: | |
10237 | ||
474c8240 | 10238 | @smallexample |
c906108c | 10239 | print a = b + c |
474c8240 | 10240 | @end smallexample |
c906108c SS |
10241 | |
10242 | @noindent | |
10243 | might not have the effect you intended. In C, this means to add | |
10244 | @code{b} and @code{c} and place the result in @code{a}. The result | |
10245 | printed would be the value of @code{a}. In Modula-2, this means to compare | |
10246 | @code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value. | |
c906108c | 10247 | |
6d2ebf8b | 10248 | @node Automatically |
79a6e687 | 10249 | @subsection Having @value{GDBN} Infer the Source Language |
c906108c SS |
10250 | |
10251 | To have @value{GDBN} set the working language automatically, use | |
10252 | @samp{set language local} or @samp{set language auto}. @value{GDBN} | |
10253 | then infers the working language. That is, when your program stops in a | |
10254 | frame (usually by encountering a breakpoint), @value{GDBN} sets the | |
10255 | working language to the language recorded for the function in that | |
10256 | frame. If the language for a frame is unknown (that is, if the function | |
10257 | or block corresponding to the frame was defined in a source file that | |
10258 | does not have a recognized extension), the current working language is | |
10259 | not changed, and @value{GDBN} issues a warning. | |
10260 | ||
10261 | This may not seem necessary for most programs, which are written | |
10262 | entirely in one source language. However, program modules and libraries | |
10263 | written in one source language can be used by a main program written in | |
10264 | a different source language. Using @samp{set language auto} in this | |
10265 | case frees you from having to set the working language manually. | |
10266 | ||
6d2ebf8b | 10267 | @node Show |
79a6e687 | 10268 | @section Displaying the Language |
c906108c SS |
10269 | |
10270 | The following commands help you find out which language is the | |
10271 | working language, and also what language source files were written in. | |
10272 | ||
c906108c SS |
10273 | @table @code |
10274 | @item show language | |
9c16f35a | 10275 | @kindex show language |
c906108c SS |
10276 | Display the current working language. This is the |
10277 | language you can use with commands such as @code{print} to | |
10278 | build and compute expressions that may involve variables in your program. | |
10279 | ||
10280 | @item info frame | |
4644b6e3 | 10281 | @kindex info frame@r{, show the source language} |
5d161b24 | 10282 | Display the source language for this frame. This language becomes the |
c906108c | 10283 | working language if you use an identifier from this frame. |
79a6e687 | 10284 | @xref{Frame Info, ,Information about a Frame}, to identify the other |
c906108c SS |
10285 | information listed here. |
10286 | ||
10287 | @item info source | |
4644b6e3 | 10288 | @kindex info source@r{, show the source language} |
c906108c | 10289 | Display the source language of this source file. |
5d161b24 | 10290 | @xref{Symbols, ,Examining the Symbol Table}, to identify the other |
c906108c SS |
10291 | information listed here. |
10292 | @end table | |
10293 | ||
10294 | In unusual circumstances, you may have source files with extensions | |
10295 | not in the standard list. You can then set the extension associated | |
10296 | with a language explicitly: | |
10297 | ||
c906108c | 10298 | @table @code |
09d4efe1 | 10299 | @item set extension-language @var{ext} @var{language} |
9c16f35a | 10300 | @kindex set extension-language |
09d4efe1 EZ |
10301 | Tell @value{GDBN} that source files with extension @var{ext} are to be |
10302 | assumed as written in the source language @var{language}. | |
c906108c SS |
10303 | |
10304 | @item info extensions | |
9c16f35a | 10305 | @kindex info extensions |
c906108c SS |
10306 | List all the filename extensions and the associated languages. |
10307 | @end table | |
10308 | ||
6d2ebf8b | 10309 | @node Checks |
79a6e687 | 10310 | @section Type and Range Checking |
c906108c SS |
10311 | |
10312 | @quotation | |
10313 | @emph{Warning:} In this release, the @value{GDBN} commands for type and range | |
10314 | checking are included, but they do not yet have any effect. This | |
10315 | section documents the intended facilities. | |
10316 | @end quotation | |
10317 | @c FIXME remove warning when type/range code added | |
10318 | ||
10319 | Some languages are designed to guard you against making seemingly common | |
10320 | errors through a series of compile- and run-time checks. These include | |
10321 | checking the type of arguments to functions and operators, and making | |
10322 | sure mathematical overflows are caught at run time. Checks such as | |
10323 | these help to ensure a program's correctness once it has been compiled | |
10324 | by eliminating type mismatches, and providing active checks for range | |
10325 | errors when your program is running. | |
10326 | ||
10327 | @value{GDBN} can check for conditions like the above if you wish. | |
9c16f35a EZ |
10328 | Although @value{GDBN} does not check the statements in your program, |
10329 | it can check expressions entered directly into @value{GDBN} for | |
10330 | evaluation via the @code{print} command, for example. As with the | |
10331 | working language, @value{GDBN} can also decide whether or not to check | |
10332 | automatically based on your program's source language. | |
79a6e687 | 10333 | @xref{Supported Languages, ,Supported Languages}, for the default |
9c16f35a | 10334 | settings of supported languages. |
c906108c SS |
10335 | |
10336 | @menu | |
10337 | * Type Checking:: An overview of type checking | |
10338 | * Range Checking:: An overview of range checking | |
10339 | @end menu | |
10340 | ||
10341 | @cindex type checking | |
10342 | @cindex checks, type | |
6d2ebf8b | 10343 | @node Type Checking |
79a6e687 | 10344 | @subsection An Overview of Type Checking |
c906108c SS |
10345 | |
10346 | Some languages, such as Modula-2, are strongly typed, meaning that the | |
10347 | arguments to operators and functions have to be of the correct type, | |
10348 | otherwise an error occurs. These checks prevent type mismatch | |
10349 | errors from ever causing any run-time problems. For example, | |
10350 | ||
10351 | @smallexample | |
10352 | 1 + 2 @result{} 3 | |
10353 | @exdent but | |
10354 | @error{} 1 + 2.3 | |
10355 | @end smallexample | |
10356 | ||
10357 | The second example fails because the @code{CARDINAL} 1 is not | |
10358 | type-compatible with the @code{REAL} 2.3. | |
10359 | ||
5d161b24 DB |
10360 | For the expressions you use in @value{GDBN} commands, you can tell the |
10361 | @value{GDBN} type checker to skip checking; | |
10362 | to treat any mismatches as errors and abandon the expression; | |
10363 | or to only issue warnings when type mismatches occur, | |
c906108c SS |
10364 | but evaluate the expression anyway. When you choose the last of |
10365 | these, @value{GDBN} evaluates expressions like the second example above, but | |
10366 | also issues a warning. | |
10367 | ||
5d161b24 DB |
10368 | Even if you turn type checking off, there may be other reasons |
10369 | related to type that prevent @value{GDBN} from evaluating an expression. | |
10370 | For instance, @value{GDBN} does not know how to add an @code{int} and | |
10371 | a @code{struct foo}. These particular type errors have nothing to do | |
10372 | with the language in use, and usually arise from expressions, such as | |
c906108c SS |
10373 | the one described above, which make little sense to evaluate anyway. |
10374 | ||
10375 | Each language defines to what degree it is strict about type. For | |
10376 | instance, both Modula-2 and C require the arguments to arithmetical | |
10377 | operators to be numbers. In C, enumerated types and pointers can be | |
10378 | represented as numbers, so that they are valid arguments to mathematical | |
79a6e687 | 10379 | operators. @xref{Supported Languages, ,Supported Languages}, for further |
c906108c SS |
10380 | details on specific languages. |
10381 | ||
10382 | @value{GDBN} provides some additional commands for controlling the type checker: | |
10383 | ||
c906108c SS |
10384 | @kindex set check type |
10385 | @kindex show check type | |
10386 | @table @code | |
10387 | @item set check type auto | |
10388 | Set type checking on or off based on the current working language. | |
79a6e687 | 10389 | @xref{Supported Languages, ,Supported Languages}, for the default settings for |
c906108c SS |
10390 | each language. |
10391 | ||
10392 | @item set check type on | |
10393 | @itemx set check type off | |
10394 | Set type checking on or off, overriding the default setting for the | |
10395 | current working language. Issue a warning if the setting does not | |
10396 | match the language default. If any type mismatches occur in | |
d4f3574e | 10397 | evaluating an expression while type checking is on, @value{GDBN} prints a |
c906108c SS |
10398 | message and aborts evaluation of the expression. |
10399 | ||
10400 | @item set check type warn | |
10401 | Cause the type checker to issue warnings, but to always attempt to | |
10402 | evaluate the expression. Evaluating the expression may still | |
10403 | be impossible for other reasons. For example, @value{GDBN} cannot add | |
10404 | numbers and structures. | |
10405 | ||
10406 | @item show type | |
5d161b24 | 10407 | Show the current setting of the type checker, and whether or not @value{GDBN} |
c906108c SS |
10408 | is setting it automatically. |
10409 | @end table | |
10410 | ||
10411 | @cindex range checking | |
10412 | @cindex checks, range | |
6d2ebf8b | 10413 | @node Range Checking |
79a6e687 | 10414 | @subsection An Overview of Range Checking |
c906108c SS |
10415 | |
10416 | In some languages (such as Modula-2), it is an error to exceed the | |
10417 | bounds of a type; this is enforced with run-time checks. Such range | |
10418 | checking is meant to ensure program correctness by making sure | |
10419 | computations do not overflow, or indices on an array element access do | |
10420 | not exceed the bounds of the array. | |
10421 | ||
10422 | For expressions you use in @value{GDBN} commands, you can tell | |
10423 | @value{GDBN} to treat range errors in one of three ways: ignore them, | |
10424 | always treat them as errors and abandon the expression, or issue | |
10425 | warnings but evaluate the expression anyway. | |
10426 | ||
10427 | A range error can result from numerical overflow, from exceeding an | |
10428 | array index bound, or when you type a constant that is not a member | |
10429 | of any type. Some languages, however, do not treat overflows as an | |
10430 | error. In many implementations of C, mathematical overflow causes the | |
10431 | result to ``wrap around'' to lower values---for example, if @var{m} is | |
10432 | the largest integer value, and @var{s} is the smallest, then | |
10433 | ||
474c8240 | 10434 | @smallexample |
c906108c | 10435 | @var{m} + 1 @result{} @var{s} |
474c8240 | 10436 | @end smallexample |
c906108c SS |
10437 | |
10438 | This, too, is specific to individual languages, and in some cases | |
79a6e687 BW |
10439 | specific to individual compilers or machines. @xref{Supported Languages, , |
10440 | Supported Languages}, for further details on specific languages. | |
c906108c SS |
10441 | |
10442 | @value{GDBN} provides some additional commands for controlling the range checker: | |
10443 | ||
c906108c SS |
10444 | @kindex set check range |
10445 | @kindex show check range | |
10446 | @table @code | |
10447 | @item set check range auto | |
10448 | Set range checking on or off based on the current working language. | |
79a6e687 | 10449 | @xref{Supported Languages, ,Supported Languages}, for the default settings for |
c906108c SS |
10450 | each language. |
10451 | ||
10452 | @item set check range on | |
10453 | @itemx set check range off | |
10454 | Set range checking on or off, overriding the default setting for the | |
10455 | current working language. A warning is issued if the setting does not | |
c3f6f71d JM |
10456 | match the language default. If a range error occurs and range checking is on, |
10457 | then a message is printed and evaluation of the expression is aborted. | |
c906108c SS |
10458 | |
10459 | @item set check range warn | |
10460 | Output messages when the @value{GDBN} range checker detects a range error, | |
10461 | but attempt to evaluate the expression anyway. Evaluating the | |
10462 | expression may still be impossible for other reasons, such as accessing | |
10463 | memory that the process does not own (a typical example from many Unix | |
10464 | systems). | |
10465 | ||
10466 | @item show range | |
10467 | Show the current setting of the range checker, and whether or not it is | |
10468 | being set automatically by @value{GDBN}. | |
10469 | @end table | |
c906108c | 10470 | |
79a6e687 BW |
10471 | @node Supported Languages |
10472 | @section Supported Languages | |
c906108c | 10473 | |
9c16f35a EZ |
10474 | @value{GDBN} supports C, C@t{++}, Objective-C, Fortran, Java, Pascal, |
10475 | assembly, Modula-2, and Ada. | |
cce74817 | 10476 | @c This is false ... |
c906108c SS |
10477 | Some @value{GDBN} features may be used in expressions regardless of the |
10478 | language you use: the @value{GDBN} @code{@@} and @code{::} operators, | |
10479 | and the @samp{@{type@}addr} construct (@pxref{Expressions, | |
10480 | ,Expressions}) can be used with the constructs of any supported | |
10481 | language. | |
10482 | ||
10483 | The following sections detail to what degree each source language is | |
10484 | supported by @value{GDBN}. These sections are not meant to be language | |
10485 | tutorials or references, but serve only as a reference guide to what the | |
10486 | @value{GDBN} expression parser accepts, and what input and output | |
10487 | formats should look like for different languages. There are many good | |
10488 | books written on each of these languages; please look to these for a | |
10489 | language reference or tutorial. | |
10490 | ||
c906108c | 10491 | @menu |
b37303ee | 10492 | * C:: C and C@t{++} |
b383017d | 10493 | * Objective-C:: Objective-C |
09d4efe1 | 10494 | * Fortran:: Fortran |
9c16f35a | 10495 | * Pascal:: Pascal |
b37303ee | 10496 | * Modula-2:: Modula-2 |
e07c999f | 10497 | * Ada:: Ada |
c906108c SS |
10498 | @end menu |
10499 | ||
6d2ebf8b | 10500 | @node C |
b37052ae | 10501 | @subsection C and C@t{++} |
7a292a7a | 10502 | |
b37052ae EZ |
10503 | @cindex C and C@t{++} |
10504 | @cindex expressions in C or C@t{++} | |
c906108c | 10505 | |
b37052ae | 10506 | Since C and C@t{++} are so closely related, many features of @value{GDBN} apply |
c906108c SS |
10507 | to both languages. Whenever this is the case, we discuss those languages |
10508 | together. | |
10509 | ||
41afff9a EZ |
10510 | @cindex C@t{++} |
10511 | @cindex @code{g++}, @sc{gnu} C@t{++} compiler | |
b37052ae EZ |
10512 | @cindex @sc{gnu} C@t{++} |
10513 | The C@t{++} debugging facilities are jointly implemented by the C@t{++} | |
10514 | compiler and @value{GDBN}. Therefore, to debug your C@t{++} code | |
10515 | effectively, you must compile your C@t{++} programs with a supported | |
10516 | C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++} | |
c906108c SS |
10517 | compiler (@code{aCC}). |
10518 | ||
0179ffac DC |
10519 | For best results when using @sc{gnu} C@t{++}, use the DWARF 2 debugging |
10520 | format; if it doesn't work on your system, try the stabs+ debugging | |
10521 | format. You can select those formats explicitly with the @code{g++} | |
10522 | command-line options @option{-gdwarf-2} and @option{-gstabs+}. | |
ce9341a1 BW |
10523 | @xref{Debugging Options,,Options for Debugging Your Program or GCC, |
10524 | gcc.info, Using the @sc{gnu} Compiler Collection (GCC)}. | |
c906108c | 10525 | |
c906108c | 10526 | @menu |
b37052ae EZ |
10527 | * C Operators:: C and C@t{++} operators |
10528 | * C Constants:: C and C@t{++} constants | |
79a6e687 | 10529 | * C Plus Plus Expressions:: C@t{++} expressions |
b37052ae EZ |
10530 | * C Defaults:: Default settings for C and C@t{++} |
10531 | * C Checks:: C and C@t{++} type and range checks | |
c906108c | 10532 | * Debugging C:: @value{GDBN} and C |
79a6e687 | 10533 | * Debugging C Plus Plus:: @value{GDBN} features for C@t{++} |
febe4383 | 10534 | * Decimal Floating Point:: Numbers in Decimal Floating Point format |
c906108c | 10535 | @end menu |
c906108c | 10536 | |
6d2ebf8b | 10537 | @node C Operators |
79a6e687 | 10538 | @subsubsection C and C@t{++} Operators |
7a292a7a | 10539 | |
b37052ae | 10540 | @cindex C and C@t{++} operators |
c906108c SS |
10541 | |
10542 | Operators must be defined on values of specific types. For instance, | |
10543 | @code{+} is defined on numbers, but not on structures. Operators are | |
5d161b24 | 10544 | often defined on groups of types. |
c906108c | 10545 | |
b37052ae | 10546 | For the purposes of C and C@t{++}, the following definitions hold: |
c906108c SS |
10547 | |
10548 | @itemize @bullet | |
53a5351d | 10549 | |
c906108c | 10550 | @item |
c906108c | 10551 | @emph{Integral types} include @code{int} with any of its storage-class |
b37052ae | 10552 | specifiers; @code{char}; @code{enum}; and, for C@t{++}, @code{bool}. |
c906108c SS |
10553 | |
10554 | @item | |
d4f3574e SS |
10555 | @emph{Floating-point types} include @code{float}, @code{double}, and |
10556 | @code{long double} (if supported by the target platform). | |
c906108c SS |
10557 | |
10558 | @item | |
53a5351d | 10559 | @emph{Pointer types} include all types defined as @code{(@var{type} *)}. |
c906108c SS |
10560 | |
10561 | @item | |
10562 | @emph{Scalar types} include all of the above. | |
53a5351d | 10563 | |
c906108c SS |
10564 | @end itemize |
10565 | ||
10566 | @noindent | |
10567 | The following operators are supported. They are listed here | |
10568 | in order of increasing precedence: | |
10569 | ||
10570 | @table @code | |
10571 | @item , | |
10572 | The comma or sequencing operator. Expressions in a comma-separated list | |
10573 | are evaluated from left to right, with the result of the entire | |
10574 | expression being the last expression evaluated. | |
10575 | ||
10576 | @item = | |
10577 | Assignment. The value of an assignment expression is the value | |
10578 | assigned. Defined on scalar types. | |
10579 | ||
10580 | @item @var{op}= | |
10581 | Used in an expression of the form @w{@code{@var{a} @var{op}= @var{b}}}, | |
10582 | and translated to @w{@code{@var{a} = @var{a op b}}}. | |
d4f3574e | 10583 | @w{@code{@var{op}=}} and @code{=} have the same precedence. |
c906108c SS |
10584 | @var{op} is any one of the operators @code{|}, @code{^}, @code{&}, |
10585 | @code{<<}, @code{>>}, @code{+}, @code{-}, @code{*}, @code{/}, @code{%}. | |
10586 | ||
10587 | @item ?: | |
10588 | The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought | |
10589 | of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an | |
10590 | integral type. | |
10591 | ||
10592 | @item || | |
10593 | Logical @sc{or}. Defined on integral types. | |
10594 | ||
10595 | @item && | |
10596 | Logical @sc{and}. Defined on integral types. | |
10597 | ||
10598 | @item | | |
10599 | Bitwise @sc{or}. Defined on integral types. | |
10600 | ||
10601 | @item ^ | |
10602 | Bitwise exclusive-@sc{or}. Defined on integral types. | |
10603 | ||
10604 | @item & | |
10605 | Bitwise @sc{and}. Defined on integral types. | |
10606 | ||
10607 | @item ==@r{, }!= | |
10608 | Equality and inequality. Defined on scalar types. The value of these | |
10609 | expressions is 0 for false and non-zero for true. | |
10610 | ||
10611 | @item <@r{, }>@r{, }<=@r{, }>= | |
10612 | Less than, greater than, less than or equal, greater than or equal. | |
10613 | Defined on scalar types. The value of these expressions is 0 for false | |
10614 | and non-zero for true. | |
10615 | ||
10616 | @item <<@r{, }>> | |
10617 | left shift, and right shift. Defined on integral types. | |
10618 | ||
10619 | @item @@ | |
10620 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
10621 | ||
10622 | @item +@r{, }- | |
10623 | Addition and subtraction. Defined on integral types, floating-point types and | |
10624 | pointer types. | |
10625 | ||
10626 | @item *@r{, }/@r{, }% | |
10627 | Multiplication, division, and modulus. Multiplication and division are | |
10628 | defined on integral and floating-point types. Modulus is defined on | |
10629 | integral types. | |
10630 | ||
10631 | @item ++@r{, }-- | |
10632 | Increment and decrement. When appearing before a variable, the | |
10633 | operation is performed before the variable is used in an expression; | |
10634 | when appearing after it, the variable's value is used before the | |
10635 | operation takes place. | |
10636 | ||
10637 | @item * | |
10638 | Pointer dereferencing. Defined on pointer types. Same precedence as | |
10639 | @code{++}. | |
10640 | ||
10641 | @item & | |
10642 | Address operator. Defined on variables. Same precedence as @code{++}. | |
10643 | ||
b37052ae EZ |
10644 | For debugging C@t{++}, @value{GDBN} implements a use of @samp{&} beyond what is |
10645 | allowed in the C@t{++} language itself: you can use @samp{&(&@var{ref})} | |
b17828ca | 10646 | to examine the address |
b37052ae | 10647 | where a C@t{++} reference variable (declared with @samp{&@var{ref}}) is |
c906108c | 10648 | stored. |
c906108c SS |
10649 | |
10650 | @item - | |
10651 | Negative. Defined on integral and floating-point types. Same | |
10652 | precedence as @code{++}. | |
10653 | ||
10654 | @item ! | |
10655 | Logical negation. Defined on integral types. Same precedence as | |
10656 | @code{++}. | |
10657 | ||
10658 | @item ~ | |
10659 | Bitwise complement operator. Defined on integral types. Same precedence as | |
10660 | @code{++}. | |
10661 | ||
10662 | ||
10663 | @item .@r{, }-> | |
10664 | Structure member, and pointer-to-structure member. For convenience, | |
10665 | @value{GDBN} regards the two as equivalent, choosing whether to dereference a | |
10666 | pointer based on the stored type information. | |
10667 | Defined on @code{struct} and @code{union} data. | |
10668 | ||
c906108c SS |
10669 | @item .*@r{, }->* |
10670 | Dereferences of pointers to members. | |
c906108c SS |
10671 | |
10672 | @item [] | |
10673 | Array indexing. @code{@var{a}[@var{i}]} is defined as | |
10674 | @code{*(@var{a}+@var{i})}. Same precedence as @code{->}. | |
10675 | ||
10676 | @item () | |
10677 | Function parameter list. Same precedence as @code{->}. | |
10678 | ||
c906108c | 10679 | @item :: |
b37052ae | 10680 | C@t{++} scope resolution operator. Defined on @code{struct}, @code{union}, |
7a292a7a | 10681 | and @code{class} types. |
c906108c SS |
10682 | |
10683 | @item :: | |
7a292a7a SS |
10684 | Doubled colons also represent the @value{GDBN} scope operator |
10685 | (@pxref{Expressions, ,Expressions}). Same precedence as @code{::}, | |
10686 | above. | |
c906108c SS |
10687 | @end table |
10688 | ||
c906108c SS |
10689 | If an operator is redefined in the user code, @value{GDBN} usually |
10690 | attempts to invoke the redefined version instead of using the operator's | |
10691 | predefined meaning. | |
c906108c | 10692 | |
6d2ebf8b | 10693 | @node C Constants |
79a6e687 | 10694 | @subsubsection C and C@t{++} Constants |
c906108c | 10695 | |
b37052ae | 10696 | @cindex C and C@t{++} constants |
c906108c | 10697 | |
b37052ae | 10698 | @value{GDBN} allows you to express the constants of C and C@t{++} in the |
c906108c | 10699 | following ways: |
c906108c SS |
10700 | |
10701 | @itemize @bullet | |
10702 | @item | |
10703 | Integer constants are a sequence of digits. Octal constants are | |
6ca652b0 EZ |
10704 | specified by a leading @samp{0} (i.e.@: zero), and hexadecimal constants |
10705 | by a leading @samp{0x} or @samp{0X}. Constants may also end with a letter | |
c906108c SS |
10706 | @samp{l}, specifying that the constant should be treated as a |
10707 | @code{long} value. | |
10708 | ||
10709 | @item | |
10710 | Floating point constants are a sequence of digits, followed by a decimal | |
10711 | point, followed by a sequence of digits, and optionally followed by an | |
10712 | exponent. An exponent is of the form: | |
10713 | @samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another | |
10714 | sequence of digits. The @samp{+} is optional for positive exponents. | |
d4f3574e SS |
10715 | A floating-point constant may also end with a letter @samp{f} or |
10716 | @samp{F}, specifying that the constant should be treated as being of | |
10717 | the @code{float} (as opposed to the default @code{double}) type; or with | |
10718 | a letter @samp{l} or @samp{L}, which specifies a @code{long double} | |
10719 | constant. | |
c906108c SS |
10720 | |
10721 | @item | |
10722 | Enumerated constants consist of enumerated identifiers, or their | |
10723 | integral equivalents. | |
10724 | ||
10725 | @item | |
10726 | Character constants are a single character surrounded by single quotes | |
10727 | (@code{'}), or a number---the ordinal value of the corresponding character | |
d4f3574e | 10728 | (usually its @sc{ascii} value). Within quotes, the single character may |
c906108c SS |
10729 | be represented by a letter or by @dfn{escape sequences}, which are of |
10730 | the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation | |
10731 | of the character's ordinal value; or of the form @samp{\@var{x}}, where | |
10732 | @samp{@var{x}} is a predefined special character---for example, | |
10733 | @samp{\n} for newline. | |
10734 | ||
10735 | @item | |
96a2c332 SS |
10736 | String constants are a sequence of character constants surrounded by |
10737 | double quotes (@code{"}). Any valid character constant (as described | |
10738 | above) may appear. Double quotes within the string must be preceded by | |
10739 | a backslash, so for instance @samp{"a\"b'c"} is a string of five | |
10740 | characters. | |
c906108c SS |
10741 | |
10742 | @item | |
10743 | Pointer constants are an integral value. You can also write pointers | |
10744 | to constants using the C operator @samp{&}. | |
10745 | ||
10746 | @item | |
10747 | Array constants are comma-separated lists surrounded by braces @samp{@{} | |
10748 | and @samp{@}}; for example, @samp{@{1,2,3@}} is a three-element array of | |
10749 | integers, @samp{@{@{1,2@}, @{3,4@}, @{5,6@}@}} is a three-by-two array, | |
10750 | and @samp{@{&"hi", &"there", &"fred"@}} is a three-element array of pointers. | |
10751 | @end itemize | |
10752 | ||
79a6e687 BW |
10753 | @node C Plus Plus Expressions |
10754 | @subsubsection C@t{++} Expressions | |
b37052ae EZ |
10755 | |
10756 | @cindex expressions in C@t{++} | |
10757 | @value{GDBN} expression handling can interpret most C@t{++} expressions. | |
10758 | ||
0179ffac DC |
10759 | @cindex debugging C@t{++} programs |
10760 | @cindex C@t{++} compilers | |
10761 | @cindex debug formats and C@t{++} | |
10762 | @cindex @value{NGCC} and C@t{++} | |
c906108c | 10763 | @quotation |
b37052ae | 10764 | @emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the |
0179ffac DC |
10765 | proper compiler and the proper debug format. Currently, @value{GDBN} |
10766 | works best when debugging C@t{++} code that is compiled with | |
10767 | @value{NGCC} 2.95.3 or with @value{NGCC} 3.1 or newer, using the options | |
10768 | @option{-gdwarf-2} or @option{-gstabs+}. DWARF 2 is preferred over | |
10769 | stabs+. Most configurations of @value{NGCC} emit either DWARF 2 or | |
10770 | stabs+ as their default debug format, so you usually don't need to | |
10771 | specify a debug format explicitly. Other compilers and/or debug formats | |
10772 | are likely to work badly or not at all when using @value{GDBN} to debug | |
10773 | C@t{++} code. | |
c906108c | 10774 | @end quotation |
c906108c SS |
10775 | |
10776 | @enumerate | |
10777 | ||
10778 | @cindex member functions | |
10779 | @item | |
10780 | Member function calls are allowed; you can use expressions like | |
10781 | ||
474c8240 | 10782 | @smallexample |
c906108c | 10783 | count = aml->GetOriginal(x, y) |
474c8240 | 10784 | @end smallexample |
c906108c | 10785 | |
41afff9a | 10786 | @vindex this@r{, inside C@t{++} member functions} |
b37052ae | 10787 | @cindex namespace in C@t{++} |
c906108c SS |
10788 | @item |
10789 | While a member function is active (in the selected stack frame), your | |
10790 | expressions have the same namespace available as the member function; | |
10791 | that is, @value{GDBN} allows implicit references to the class instance | |
b37052ae | 10792 | pointer @code{this} following the same rules as C@t{++}. |
c906108c | 10793 | |
c906108c | 10794 | @cindex call overloaded functions |
d4f3574e | 10795 | @cindex overloaded functions, calling |
b37052ae | 10796 | @cindex type conversions in C@t{++} |
c906108c SS |
10797 | @item |
10798 | You can call overloaded functions; @value{GDBN} resolves the function | |
d4f3574e | 10799 | call to the right definition, with some restrictions. @value{GDBN} does not |
c906108c SS |
10800 | perform overload resolution involving user-defined type conversions, |
10801 | calls to constructors, or instantiations of templates that do not exist | |
10802 | in the program. It also cannot handle ellipsis argument lists or | |
10803 | default arguments. | |
10804 | ||
10805 | It does perform integral conversions and promotions, floating-point | |
10806 | promotions, arithmetic conversions, pointer conversions, conversions of | |
10807 | class objects to base classes, and standard conversions such as those of | |
10808 | functions or arrays to pointers; it requires an exact match on the | |
10809 | number of function arguments. | |
10810 | ||
10811 | Overload resolution is always performed, unless you have specified | |
79a6e687 BW |
10812 | @code{set overload-resolution off}. @xref{Debugging C Plus Plus, |
10813 | ,@value{GDBN} Features for C@t{++}}. | |
c906108c | 10814 | |
d4f3574e | 10815 | You must specify @code{set overload-resolution off} in order to use an |
c906108c SS |
10816 | explicit function signature to call an overloaded function, as in |
10817 | @smallexample | |
10818 | p 'foo(char,int)'('x', 13) | |
10819 | @end smallexample | |
d4f3574e | 10820 | |
c906108c | 10821 | The @value{GDBN} command-completion facility can simplify this; |
79a6e687 | 10822 | see @ref{Completion, ,Command Completion}. |
c906108c | 10823 | |
c906108c SS |
10824 | @cindex reference declarations |
10825 | @item | |
b37052ae EZ |
10826 | @value{GDBN} understands variables declared as C@t{++} references; you can use |
10827 | them in expressions just as you do in C@t{++} source---they are automatically | |
c906108c SS |
10828 | dereferenced. |
10829 | ||
10830 | In the parameter list shown when @value{GDBN} displays a frame, the values of | |
10831 | reference variables are not displayed (unlike other variables); this | |
10832 | avoids clutter, since references are often used for large structures. | |
10833 | The @emph{address} of a reference variable is always shown, unless | |
10834 | you have specified @samp{set print address off}. | |
10835 | ||
10836 | @item | |
b37052ae | 10837 | @value{GDBN} supports the C@t{++} name resolution operator @code{::}---your |
c906108c SS |
10838 | expressions can use it just as expressions in your program do. Since |
10839 | one scope may be defined in another, you can use @code{::} repeatedly if | |
10840 | necessary, for example in an expression like | |
10841 | @samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows | |
b37052ae | 10842 | resolving name scope by reference to source files, in both C and C@t{++} |
79a6e687 | 10843 | debugging (@pxref{Variables, ,Program Variables}). |
c906108c SS |
10844 | @end enumerate |
10845 | ||
b37052ae | 10846 | In addition, when used with HP's C@t{++} compiler, @value{GDBN} supports |
53a5351d JM |
10847 | calling virtual functions correctly, printing out virtual bases of |
10848 | objects, calling functions in a base subobject, casting objects, and | |
10849 | invoking user-defined operators. | |
c906108c | 10850 | |
6d2ebf8b | 10851 | @node C Defaults |
79a6e687 | 10852 | @subsubsection C and C@t{++} Defaults |
7a292a7a | 10853 | |
b37052ae | 10854 | @cindex C and C@t{++} defaults |
c906108c | 10855 | |
c906108c SS |
10856 | If you allow @value{GDBN} to set type and range checking automatically, they |
10857 | both default to @code{off} whenever the working language changes to | |
b37052ae | 10858 | C or C@t{++}. This happens regardless of whether you or @value{GDBN} |
c906108c | 10859 | selects the working language. |
c906108c SS |
10860 | |
10861 | If you allow @value{GDBN} to set the language automatically, it | |
10862 | recognizes source files whose names end with @file{.c}, @file{.C}, or | |
10863 | @file{.cc}, etc, and when @value{GDBN} enters code compiled from one of | |
b37052ae | 10864 | these files, it sets the working language to C or C@t{++}. |
79a6e687 | 10865 | @xref{Automatically, ,Having @value{GDBN} Infer the Source Language}, |
c906108c SS |
10866 | for further details. |
10867 | ||
c906108c SS |
10868 | @c Type checking is (a) primarily motivated by Modula-2, and (b) |
10869 | @c unimplemented. If (b) changes, it might make sense to let this node | |
10870 | @c appear even if Mod-2 does not, but meanwhile ignore it. roland 16jul93. | |
7a292a7a | 10871 | |
6d2ebf8b | 10872 | @node C Checks |
79a6e687 | 10873 | @subsubsection C and C@t{++} Type and Range Checks |
7a292a7a | 10874 | |
b37052ae | 10875 | @cindex C and C@t{++} checks |
c906108c | 10876 | |
b37052ae | 10877 | By default, when @value{GDBN} parses C or C@t{++} expressions, type checking |
c906108c SS |
10878 | is not used. However, if you turn type checking on, @value{GDBN} |
10879 | considers two variables type equivalent if: | |
10880 | ||
10881 | @itemize @bullet | |
10882 | @item | |
10883 | The two variables are structured and have the same structure, union, or | |
10884 | enumerated tag. | |
10885 | ||
10886 | @item | |
10887 | The two variables have the same type name, or types that have been | |
10888 | declared equivalent through @code{typedef}. | |
10889 | ||
10890 | @ignore | |
10891 | @c leaving this out because neither J Gilmore nor R Pesch understand it. | |
10892 | @c FIXME--beers? | |
10893 | @item | |
10894 | The two @code{struct}, @code{union}, or @code{enum} variables are | |
10895 | declared in the same declaration. (Note: this may not be true for all C | |
10896 | compilers.) | |
10897 | @end ignore | |
10898 | @end itemize | |
10899 | ||
10900 | Range checking, if turned on, is done on mathematical operations. Array | |
10901 | indices are not checked, since they are often used to index a pointer | |
10902 | that is not itself an array. | |
c906108c | 10903 | |
6d2ebf8b | 10904 | @node Debugging C |
c906108c | 10905 | @subsubsection @value{GDBN} and C |
c906108c SS |
10906 | |
10907 | The @code{set print union} and @code{show print union} commands apply to | |
10908 | the @code{union} type. When set to @samp{on}, any @code{union} that is | |
7a292a7a SS |
10909 | inside a @code{struct} or @code{class} is also printed. Otherwise, it |
10910 | appears as @samp{@{...@}}. | |
c906108c SS |
10911 | |
10912 | The @code{@@} operator aids in the debugging of dynamic arrays, formed | |
10913 | with pointers and a memory allocation function. @xref{Expressions, | |
10914 | ,Expressions}. | |
10915 | ||
79a6e687 BW |
10916 | @node Debugging C Plus Plus |
10917 | @subsubsection @value{GDBN} Features for C@t{++} | |
c906108c | 10918 | |
b37052ae | 10919 | @cindex commands for C@t{++} |
7a292a7a | 10920 | |
b37052ae EZ |
10921 | Some @value{GDBN} commands are particularly useful with C@t{++}, and some are |
10922 | designed specifically for use with C@t{++}. Here is a summary: | |
c906108c SS |
10923 | |
10924 | @table @code | |
10925 | @cindex break in overloaded functions | |
10926 | @item @r{breakpoint menus} | |
10927 | When you want a breakpoint in a function whose name is overloaded, | |
6ba66d6a JB |
10928 | @value{GDBN} has the capability to display a menu of possible breakpoint |
10929 | locations to help you specify which function definition you want. | |
10930 | @xref{Ambiguous Expressions,,Ambiguous Expressions}. | |
c906108c | 10931 | |
b37052ae | 10932 | @cindex overloading in C@t{++} |
c906108c SS |
10933 | @item rbreak @var{regex} |
10934 | Setting breakpoints using regular expressions is helpful for setting | |
10935 | breakpoints on overloaded functions that are not members of any special | |
10936 | classes. | |
79a6e687 | 10937 | @xref{Set Breaks, ,Setting Breakpoints}. |
c906108c | 10938 | |
b37052ae | 10939 | @cindex C@t{++} exception handling |
c906108c SS |
10940 | @item catch throw |
10941 | @itemx catch catch | |
b37052ae | 10942 | Debug C@t{++} exception handling using these commands. @xref{Set |
79a6e687 | 10943 | Catchpoints, , Setting Catchpoints}. |
c906108c SS |
10944 | |
10945 | @cindex inheritance | |
10946 | @item ptype @var{typename} | |
10947 | Print inheritance relationships as well as other information for type | |
10948 | @var{typename}. | |
10949 | @xref{Symbols, ,Examining the Symbol Table}. | |
10950 | ||
b37052ae | 10951 | @cindex C@t{++} symbol display |
c906108c SS |
10952 | @item set print demangle |
10953 | @itemx show print demangle | |
10954 | @itemx set print asm-demangle | |
10955 | @itemx show print asm-demangle | |
b37052ae EZ |
10956 | Control whether C@t{++} symbols display in their source form, both when |
10957 | displaying code as C@t{++} source and when displaying disassemblies. | |
79a6e687 | 10958 | @xref{Print Settings, ,Print Settings}. |
c906108c SS |
10959 | |
10960 | @item set print object | |
10961 | @itemx show print object | |
10962 | Choose whether to print derived (actual) or declared types of objects. | |
79a6e687 | 10963 | @xref{Print Settings, ,Print Settings}. |
c906108c SS |
10964 | |
10965 | @item set print vtbl | |
10966 | @itemx show print vtbl | |
10967 | Control the format for printing virtual function tables. | |
79a6e687 | 10968 | @xref{Print Settings, ,Print Settings}. |
c906108c | 10969 | (The @code{vtbl} commands do not work on programs compiled with the HP |
b37052ae | 10970 | ANSI C@t{++} compiler (@code{aCC}).) |
c906108c SS |
10971 | |
10972 | @kindex set overload-resolution | |
d4f3574e | 10973 | @cindex overloaded functions, overload resolution |
c906108c | 10974 | @item set overload-resolution on |
b37052ae | 10975 | Enable overload resolution for C@t{++} expression evaluation. The default |
c906108c SS |
10976 | is on. For overloaded functions, @value{GDBN} evaluates the arguments |
10977 | and searches for a function whose signature matches the argument types, | |
79a6e687 BW |
10978 | using the standard C@t{++} conversion rules (see @ref{C Plus Plus |
10979 | Expressions, ,C@t{++} Expressions}, for details). | |
10980 | If it cannot find a match, it emits a message. | |
c906108c SS |
10981 | |
10982 | @item set overload-resolution off | |
b37052ae | 10983 | Disable overload resolution for C@t{++} expression evaluation. For |
c906108c SS |
10984 | overloaded functions that are not class member functions, @value{GDBN} |
10985 | chooses the first function of the specified name that it finds in the | |
10986 | symbol table, whether or not its arguments are of the correct type. For | |
10987 | overloaded functions that are class member functions, @value{GDBN} | |
10988 | searches for a function whose signature @emph{exactly} matches the | |
10989 | argument types. | |
c906108c | 10990 | |
9c16f35a EZ |
10991 | @kindex show overload-resolution |
10992 | @item show overload-resolution | |
10993 | Show the current setting of overload resolution. | |
10994 | ||
c906108c SS |
10995 | @item @r{Overloaded symbol names} |
10996 | You can specify a particular definition of an overloaded symbol, using | |
b37052ae | 10997 | the same notation that is used to declare such symbols in C@t{++}: type |
c906108c SS |
10998 | @code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can |
10999 | also use the @value{GDBN} command-line word completion facilities to list the | |
11000 | available choices, or to finish the type list for you. | |
79a6e687 | 11001 | @xref{Completion,, Command Completion}, for details on how to do this. |
c906108c | 11002 | @end table |
c906108c | 11003 | |
febe4383 TJB |
11004 | @node Decimal Floating Point |
11005 | @subsubsection Decimal Floating Point format | |
11006 | @cindex decimal floating point format | |
11007 | ||
11008 | @value{GDBN} can examine, set and perform computations with numbers in | |
11009 | decimal floating point format, which in the C language correspond to the | |
11010 | @code{_Decimal32}, @code{_Decimal64} and @code{_Decimal128} types as | |
11011 | specified by the extension to support decimal floating-point arithmetic. | |
11012 | ||
11013 | There are two encodings in use, depending on the architecture: BID (Binary | |
11014 | Integer Decimal) for x86 and x86-64, and DPD (Densely Packed Decimal) for | |
99e008fe | 11015 | PowerPC. @value{GDBN} will use the appropriate encoding for the configured |
febe4383 TJB |
11016 | target. |
11017 | ||
11018 | Because of a limitation in @file{libdecnumber}, the library used by @value{GDBN} | |
11019 | to manipulate decimal floating point numbers, it is not possible to convert | |
11020 | (using a cast, for example) integers wider than 32-bit to decimal float. | |
11021 | ||
11022 | In addition, in order to imitate @value{GDBN}'s behaviour with binary floating | |
11023 | point computations, error checking in decimal float operations ignores | |
11024 | underflow, overflow and divide by zero exceptions. | |
11025 | ||
4acd40f3 | 11026 | In the PowerPC architecture, @value{GDBN} provides a set of pseudo-registers |
99e008fe EZ |
11027 | to inspect @code{_Decimal128} values stored in floating point registers. |
11028 | See @ref{PowerPC,,PowerPC} for more details. | |
4acd40f3 | 11029 | |
b37303ee AF |
11030 | @node Objective-C |
11031 | @subsection Objective-C | |
11032 | ||
11033 | @cindex Objective-C | |
11034 | This section provides information about some commands and command | |
721c2651 EZ |
11035 | options that are useful for debugging Objective-C code. See also |
11036 | @ref{Symbols, info classes}, and @ref{Symbols, info selectors}, for a | |
11037 | few more commands specific to Objective-C support. | |
b37303ee AF |
11038 | |
11039 | @menu | |
b383017d RM |
11040 | * Method Names in Commands:: |
11041 | * The Print Command with Objective-C:: | |
b37303ee AF |
11042 | @end menu |
11043 | ||
c8f4133a | 11044 | @node Method Names in Commands |
b37303ee AF |
11045 | @subsubsection Method Names in Commands |
11046 | ||
11047 | The following commands have been extended to accept Objective-C method | |
11048 | names as line specifications: | |
11049 | ||
11050 | @kindex clear@r{, and Objective-C} | |
11051 | @kindex break@r{, and Objective-C} | |
11052 | @kindex info line@r{, and Objective-C} | |
11053 | @kindex jump@r{, and Objective-C} | |
11054 | @kindex list@r{, and Objective-C} | |
11055 | @itemize | |
11056 | @item @code{clear} | |
11057 | @item @code{break} | |
11058 | @item @code{info line} | |
11059 | @item @code{jump} | |
11060 | @item @code{list} | |
11061 | @end itemize | |
11062 | ||
11063 | A fully qualified Objective-C method name is specified as | |
11064 | ||
11065 | @smallexample | |
11066 | -[@var{Class} @var{methodName}] | |
11067 | @end smallexample | |
11068 | ||
c552b3bb JM |
11069 | where the minus sign is used to indicate an instance method and a |
11070 | plus sign (not shown) is used to indicate a class method. The class | |
11071 | name @var{Class} and method name @var{methodName} are enclosed in | |
11072 | brackets, similar to the way messages are specified in Objective-C | |
11073 | source code. For example, to set a breakpoint at the @code{create} | |
11074 | instance method of class @code{Fruit} in the program currently being | |
11075 | debugged, enter: | |
b37303ee AF |
11076 | |
11077 | @smallexample | |
11078 | break -[Fruit create] | |
11079 | @end smallexample | |
11080 | ||
11081 | To list ten program lines around the @code{initialize} class method, | |
11082 | enter: | |
11083 | ||
11084 | @smallexample | |
11085 | list +[NSText initialize] | |
11086 | @end smallexample | |
11087 | ||
c552b3bb JM |
11088 | In the current version of @value{GDBN}, the plus or minus sign is |
11089 | required. In future versions of @value{GDBN}, the plus or minus | |
11090 | sign will be optional, but you can use it to narrow the search. It | |
11091 | is also possible to specify just a method name: | |
b37303ee AF |
11092 | |
11093 | @smallexample | |
11094 | break create | |
11095 | @end smallexample | |
11096 | ||
11097 | You must specify the complete method name, including any colons. If | |
11098 | your program's source files contain more than one @code{create} method, | |
11099 | you'll be presented with a numbered list of classes that implement that | |
11100 | method. Indicate your choice by number, or type @samp{0} to exit if | |
11101 | none apply. | |
11102 | ||
11103 | As another example, to clear a breakpoint established at the | |
11104 | @code{makeKeyAndOrderFront:} method of the @code{NSWindow} class, enter: | |
11105 | ||
11106 | @smallexample | |
11107 | clear -[NSWindow makeKeyAndOrderFront:] | |
11108 | @end smallexample | |
11109 | ||
11110 | @node The Print Command with Objective-C | |
11111 | @subsubsection The Print Command With Objective-C | |
721c2651 | 11112 | @cindex Objective-C, print objects |
c552b3bb JM |
11113 | @kindex print-object |
11114 | @kindex po @r{(@code{print-object})} | |
b37303ee | 11115 | |
c552b3bb | 11116 | The print command has also been extended to accept methods. For example: |
b37303ee AF |
11117 | |
11118 | @smallexample | |
c552b3bb | 11119 | print -[@var{object} hash] |
b37303ee AF |
11120 | @end smallexample |
11121 | ||
11122 | @cindex print an Objective-C object description | |
c552b3bb JM |
11123 | @cindex @code{_NSPrintForDebugger}, and printing Objective-C objects |
11124 | @noindent | |
11125 | will tell @value{GDBN} to send the @code{hash} message to @var{object} | |
11126 | and print the result. Also, an additional command has been added, | |
11127 | @code{print-object} or @code{po} for short, which is meant to print | |
11128 | the description of an object. However, this command may only work | |
11129 | with certain Objective-C libraries that have a particular hook | |
11130 | function, @code{_NSPrintForDebugger}, defined. | |
b37303ee | 11131 | |
09d4efe1 EZ |
11132 | @node Fortran |
11133 | @subsection Fortran | |
11134 | @cindex Fortran-specific support in @value{GDBN} | |
11135 | ||
814e32d7 WZ |
11136 | @value{GDBN} can be used to debug programs written in Fortran, but it |
11137 | currently supports only the features of Fortran 77 language. | |
11138 | ||
11139 | @cindex trailing underscore, in Fortran symbols | |
11140 | Some Fortran compilers (@sc{gnu} Fortran 77 and Fortran 95 compilers | |
11141 | among them) append an underscore to the names of variables and | |
11142 | functions. When you debug programs compiled by those compilers, you | |
11143 | will need to refer to variables and functions with a trailing | |
11144 | underscore. | |
11145 | ||
11146 | @menu | |
11147 | * Fortran Operators:: Fortran operators and expressions | |
11148 | * Fortran Defaults:: Default settings for Fortran | |
79a6e687 | 11149 | * Special Fortran Commands:: Special @value{GDBN} commands for Fortran |
814e32d7 WZ |
11150 | @end menu |
11151 | ||
11152 | @node Fortran Operators | |
79a6e687 | 11153 | @subsubsection Fortran Operators and Expressions |
814e32d7 WZ |
11154 | |
11155 | @cindex Fortran operators and expressions | |
11156 | ||
11157 | Operators must be defined on values of specific types. For instance, | |
11158 | @code{+} is defined on numbers, but not on characters or other non- | |
ff2587ec | 11159 | arithmetic types. Operators are often defined on groups of types. |
814e32d7 WZ |
11160 | |
11161 | @table @code | |
11162 | @item ** | |
99e008fe | 11163 | The exponentiation operator. It raises the first operand to the power |
814e32d7 WZ |
11164 | of the second one. |
11165 | ||
11166 | @item : | |
11167 | The range operator. Normally used in the form of array(low:high) to | |
11168 | represent a section of array. | |
68837c9d MD |
11169 | |
11170 | @item % | |
11171 | The access component operator. Normally used to access elements in derived | |
11172 | types. Also suitable for unions. As unions aren't part of regular Fortran, | |
11173 | this can only happen when accessing a register that uses a gdbarch-defined | |
11174 | union type. | |
814e32d7 WZ |
11175 | @end table |
11176 | ||
11177 | @node Fortran Defaults | |
11178 | @subsubsection Fortran Defaults | |
11179 | ||
11180 | @cindex Fortran Defaults | |
11181 | ||
11182 | Fortran symbols are usually case-insensitive, so @value{GDBN} by | |
11183 | default uses case-insensitive matches for Fortran symbols. You can | |
11184 | change that with the @samp{set case-insensitive} command, see | |
11185 | @ref{Symbols}, for the details. | |
11186 | ||
79a6e687 BW |
11187 | @node Special Fortran Commands |
11188 | @subsubsection Special Fortran Commands | |
814e32d7 WZ |
11189 | |
11190 | @cindex Special Fortran commands | |
11191 | ||
db2e3e2e BW |
11192 | @value{GDBN} has some commands to support Fortran-specific features, |
11193 | such as displaying common blocks. | |
814e32d7 | 11194 | |
09d4efe1 EZ |
11195 | @table @code |
11196 | @cindex @code{COMMON} blocks, Fortran | |
11197 | @kindex info common | |
11198 | @item info common @r{[}@var{common-name}@r{]} | |
11199 | This command prints the values contained in the Fortran @code{COMMON} | |
11200 | block whose name is @var{common-name}. With no argument, the names of | |
d52fb0e9 | 11201 | all @code{COMMON} blocks visible at the current program location are |
09d4efe1 EZ |
11202 | printed. |
11203 | @end table | |
11204 | ||
9c16f35a EZ |
11205 | @node Pascal |
11206 | @subsection Pascal | |
11207 | ||
11208 | @cindex Pascal support in @value{GDBN}, limitations | |
11209 | Debugging Pascal programs which use sets, subranges, file variables, or | |
11210 | nested functions does not currently work. @value{GDBN} does not support | |
11211 | entering expressions, printing values, or similar features using Pascal | |
11212 | syntax. | |
11213 | ||
11214 | The Pascal-specific command @code{set print pascal_static-members} | |
11215 | controls whether static members of Pascal objects are displayed. | |
11216 | @xref{Print Settings, pascal_static-members}. | |
11217 | ||
09d4efe1 | 11218 | @node Modula-2 |
c906108c | 11219 | @subsection Modula-2 |
7a292a7a | 11220 | |
d4f3574e | 11221 | @cindex Modula-2, @value{GDBN} support |
c906108c SS |
11222 | |
11223 | The extensions made to @value{GDBN} to support Modula-2 only support | |
11224 | output from the @sc{gnu} Modula-2 compiler (which is currently being | |
11225 | developed). Other Modula-2 compilers are not currently supported, and | |
11226 | attempting to debug executables produced by them is most likely | |
11227 | to give an error as @value{GDBN} reads in the executable's symbol | |
11228 | table. | |
11229 | ||
11230 | @cindex expressions in Modula-2 | |
11231 | @menu | |
11232 | * M2 Operators:: Built-in operators | |
11233 | * Built-In Func/Proc:: Built-in functions and procedures | |
11234 | * M2 Constants:: Modula-2 constants | |
72019c9c | 11235 | * M2 Types:: Modula-2 types |
c906108c SS |
11236 | * M2 Defaults:: Default settings for Modula-2 |
11237 | * Deviations:: Deviations from standard Modula-2 | |
11238 | * M2 Checks:: Modula-2 type and range checks | |
11239 | * M2 Scope:: The scope operators @code{::} and @code{.} | |
11240 | * GDB/M2:: @value{GDBN} and Modula-2 | |
11241 | @end menu | |
11242 | ||
6d2ebf8b | 11243 | @node M2 Operators |
c906108c SS |
11244 | @subsubsection Operators |
11245 | @cindex Modula-2 operators | |
11246 | ||
11247 | Operators must be defined on values of specific types. For instance, | |
11248 | @code{+} is defined on numbers, but not on structures. Operators are | |
11249 | often defined on groups of types. For the purposes of Modula-2, the | |
11250 | following definitions hold: | |
11251 | ||
11252 | @itemize @bullet | |
11253 | ||
11254 | @item | |
11255 | @emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and | |
11256 | their subranges. | |
11257 | ||
11258 | @item | |
11259 | @emph{Character types} consist of @code{CHAR} and its subranges. | |
11260 | ||
11261 | @item | |
11262 | @emph{Floating-point types} consist of @code{REAL}. | |
11263 | ||
11264 | @item | |
11265 | @emph{Pointer types} consist of anything declared as @code{POINTER TO | |
11266 | @var{type}}. | |
11267 | ||
11268 | @item | |
11269 | @emph{Scalar types} consist of all of the above. | |
11270 | ||
11271 | @item | |
11272 | @emph{Set types} consist of @code{SET} and @code{BITSET} types. | |
11273 | ||
11274 | @item | |
11275 | @emph{Boolean types} consist of @code{BOOLEAN}. | |
11276 | @end itemize | |
11277 | ||
11278 | @noindent | |
11279 | The following operators are supported, and appear in order of | |
11280 | increasing precedence: | |
11281 | ||
11282 | @table @code | |
11283 | @item , | |
11284 | Function argument or array index separator. | |
11285 | ||
11286 | @item := | |
11287 | Assignment. The value of @var{var} @code{:=} @var{value} is | |
11288 | @var{value}. | |
11289 | ||
11290 | @item <@r{, }> | |
11291 | Less than, greater than on integral, floating-point, or enumerated | |
11292 | types. | |
11293 | ||
11294 | @item <=@r{, }>= | |
96a2c332 | 11295 | Less than or equal to, greater than or equal to |
c906108c SS |
11296 | on integral, floating-point and enumerated types, or set inclusion on |
11297 | set types. Same precedence as @code{<}. | |
11298 | ||
11299 | @item =@r{, }<>@r{, }# | |
11300 | Equality and two ways of expressing inequality, valid on scalar types. | |
11301 | Same precedence as @code{<}. In @value{GDBN} scripts, only @code{<>} is | |
11302 | available for inequality, since @code{#} conflicts with the script | |
11303 | comment character. | |
11304 | ||
11305 | @item IN | |
11306 | Set membership. Defined on set types and the types of their members. | |
11307 | Same precedence as @code{<}. | |
11308 | ||
11309 | @item OR | |
11310 | Boolean disjunction. Defined on boolean types. | |
11311 | ||
11312 | @item AND@r{, }& | |
d4f3574e | 11313 | Boolean conjunction. Defined on boolean types. |
c906108c SS |
11314 | |
11315 | @item @@ | |
11316 | The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}). | |
11317 | ||
11318 | @item +@r{, }- | |
11319 | Addition and subtraction on integral and floating-point types, or union | |
11320 | and difference on set types. | |
11321 | ||
11322 | @item * | |
11323 | Multiplication on integral and floating-point types, or set intersection | |
11324 | on set types. | |
11325 | ||
11326 | @item / | |
11327 | Division on floating-point types, or symmetric set difference on set | |
11328 | types. Same precedence as @code{*}. | |
11329 | ||
11330 | @item DIV@r{, }MOD | |
11331 | Integer division and remainder. Defined on integral types. Same | |
11332 | precedence as @code{*}. | |
11333 | ||
11334 | @item - | |
99e008fe | 11335 | Negative. Defined on @code{INTEGER} and @code{REAL} data. |
c906108c SS |
11336 | |
11337 | @item ^ | |
11338 | Pointer dereferencing. Defined on pointer types. | |
11339 | ||
11340 | @item NOT | |
11341 | Boolean negation. Defined on boolean types. Same precedence as | |
11342 | @code{^}. | |
11343 | ||
11344 | @item . | |
11345 | @code{RECORD} field selector. Defined on @code{RECORD} data. Same | |
11346 | precedence as @code{^}. | |
11347 | ||
11348 | @item [] | |
11349 | Array indexing. Defined on @code{ARRAY} data. Same precedence as @code{^}. | |
11350 | ||
11351 | @item () | |
11352 | Procedure argument list. Defined on @code{PROCEDURE} objects. Same precedence | |
11353 | as @code{^}. | |
11354 | ||
11355 | @item ::@r{, }. | |
11356 | @value{GDBN} and Modula-2 scope operators. | |
11357 | @end table | |
11358 | ||
11359 | @quotation | |
72019c9c | 11360 | @emph{Warning:} Set expressions and their operations are not yet supported, so @value{GDBN} |
c906108c SS |
11361 | treats the use of the operator @code{IN}, or the use of operators |
11362 | @code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#}, | |
11363 | @code{<=}, and @code{>=} on sets as an error. | |
11364 | @end quotation | |
11365 | ||
cb51c4e0 | 11366 | |
6d2ebf8b | 11367 | @node Built-In Func/Proc |
79a6e687 | 11368 | @subsubsection Built-in Functions and Procedures |
cb51c4e0 | 11369 | @cindex Modula-2 built-ins |
c906108c SS |
11370 | |
11371 | Modula-2 also makes available several built-in procedures and functions. | |
11372 | In describing these, the following metavariables are used: | |
11373 | ||
11374 | @table @var | |
11375 | ||
11376 | @item a | |
11377 | represents an @code{ARRAY} variable. | |
11378 | ||
11379 | @item c | |
11380 | represents a @code{CHAR} constant or variable. | |
11381 | ||
11382 | @item i | |
11383 | represents a variable or constant of integral type. | |
11384 | ||
11385 | @item m | |
11386 | represents an identifier that belongs to a set. Generally used in the | |
11387 | same function with the metavariable @var{s}. The type of @var{s} should | |
11388 | be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}). | |
11389 | ||
11390 | @item n | |
11391 | represents a variable or constant of integral or floating-point type. | |
11392 | ||
11393 | @item r | |
11394 | represents a variable or constant of floating-point type. | |
11395 | ||
11396 | @item t | |
11397 | represents a type. | |
11398 | ||
11399 | @item v | |
11400 | represents a variable. | |
11401 | ||
11402 | @item x | |
11403 | represents a variable or constant of one of many types. See the | |
11404 | explanation of the function for details. | |
11405 | @end table | |
11406 | ||
11407 | All Modula-2 built-in procedures also return a result, described below. | |
11408 | ||
11409 | @table @code | |
11410 | @item ABS(@var{n}) | |
11411 | Returns the absolute value of @var{n}. | |
11412 | ||
11413 | @item CAP(@var{c}) | |
11414 | If @var{c} is a lower case letter, it returns its upper case | |
c3f6f71d | 11415 | equivalent, otherwise it returns its argument. |
c906108c SS |
11416 | |
11417 | @item CHR(@var{i}) | |
11418 | Returns the character whose ordinal value is @var{i}. | |
11419 | ||
11420 | @item DEC(@var{v}) | |
c3f6f71d | 11421 | Decrements the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
11422 | |
11423 | @item DEC(@var{v},@var{i}) | |
11424 | Decrements the value in the variable @var{v} by @var{i}. Returns the | |
11425 | new value. | |
11426 | ||
11427 | @item EXCL(@var{m},@var{s}) | |
11428 | Removes the element @var{m} from the set @var{s}. Returns the new | |
11429 | set. | |
11430 | ||
11431 | @item FLOAT(@var{i}) | |
11432 | Returns the floating point equivalent of the integer @var{i}. | |
11433 | ||
11434 | @item HIGH(@var{a}) | |
11435 | Returns the index of the last member of @var{a}. | |
11436 | ||
11437 | @item INC(@var{v}) | |
c3f6f71d | 11438 | Increments the value in the variable @var{v} by one. Returns the new value. |
c906108c SS |
11439 | |
11440 | @item INC(@var{v},@var{i}) | |
11441 | Increments the value in the variable @var{v} by @var{i}. Returns the | |
11442 | new value. | |
11443 | ||
11444 | @item INCL(@var{m},@var{s}) | |
11445 | Adds the element @var{m} to the set @var{s} if it is not already | |
11446 | there. Returns the new set. | |
11447 | ||
11448 | @item MAX(@var{t}) | |
11449 | Returns the maximum value of the type @var{t}. | |
11450 | ||
11451 | @item MIN(@var{t}) | |
11452 | Returns the minimum value of the type @var{t}. | |
11453 | ||
11454 | @item ODD(@var{i}) | |
11455 | Returns boolean TRUE if @var{i} is an odd number. | |
11456 | ||
11457 | @item ORD(@var{x}) | |
11458 | Returns the ordinal value of its argument. For example, the ordinal | |
c3f6f71d JM |
11459 | value of a character is its @sc{ascii} value (on machines supporting the |
11460 | @sc{ascii} character set). @var{x} must be of an ordered type, which include | |
c906108c SS |
11461 | integral, character and enumerated types. |
11462 | ||
11463 | @item SIZE(@var{x}) | |
11464 | Returns the size of its argument. @var{x} can be a variable or a type. | |
11465 | ||
11466 | @item TRUNC(@var{r}) | |
11467 | Returns the integral part of @var{r}. | |
11468 | ||
844781a1 GM |
11469 | @item TSIZE(@var{x}) |
11470 | Returns the size of its argument. @var{x} can be a variable or a type. | |
11471 | ||
c906108c SS |
11472 | @item VAL(@var{t},@var{i}) |
11473 | Returns the member of the type @var{t} whose ordinal value is @var{i}. | |
11474 | @end table | |
11475 | ||
11476 | @quotation | |
11477 | @emph{Warning:} Sets and their operations are not yet supported, so | |
11478 | @value{GDBN} treats the use of procedures @code{INCL} and @code{EXCL} as | |
11479 | an error. | |
11480 | @end quotation | |
11481 | ||
11482 | @cindex Modula-2 constants | |
6d2ebf8b | 11483 | @node M2 Constants |
c906108c SS |
11484 | @subsubsection Constants |
11485 | ||
11486 | @value{GDBN} allows you to express the constants of Modula-2 in the following | |
11487 | ways: | |
11488 | ||
11489 | @itemize @bullet | |
11490 | ||
11491 | @item | |
11492 | Integer constants are simply a sequence of digits. When used in an | |
11493 | expression, a constant is interpreted to be type-compatible with the | |
11494 | rest of the expression. Hexadecimal integers are specified by a | |
11495 | trailing @samp{H}, and octal integers by a trailing @samp{B}. | |
11496 | ||
11497 | @item | |
11498 | Floating point constants appear as a sequence of digits, followed by a | |
11499 | decimal point and another sequence of digits. An optional exponent can | |
11500 | then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where | |
11501 | @samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the | |
11502 | digits of the floating point constant must be valid decimal (base 10) | |
11503 | digits. | |
11504 | ||
11505 | @item | |
11506 | Character constants consist of a single character enclosed by a pair of | |
11507 | like quotes, either single (@code{'}) or double (@code{"}). They may | |
c3f6f71d | 11508 | also be expressed by their ordinal value (their @sc{ascii} value, usually) |
c906108c SS |
11509 | followed by a @samp{C}. |
11510 | ||
11511 | @item | |
11512 | String constants consist of a sequence of characters enclosed by a | |
11513 | pair of like quotes, either single (@code{'}) or double (@code{"}). | |
11514 | Escape sequences in the style of C are also allowed. @xref{C | |
79a6e687 | 11515 | Constants, ,C and C@t{++} Constants}, for a brief explanation of escape |
c906108c SS |
11516 | sequences. |
11517 | ||
11518 | @item | |
11519 | Enumerated constants consist of an enumerated identifier. | |
11520 | ||
11521 | @item | |
11522 | Boolean constants consist of the identifiers @code{TRUE} and | |
11523 | @code{FALSE}. | |
11524 | ||
11525 | @item | |
11526 | Pointer constants consist of integral values only. | |
11527 | ||
11528 | @item | |
11529 | Set constants are not yet supported. | |
11530 | @end itemize | |
11531 | ||
72019c9c GM |
11532 | @node M2 Types |
11533 | @subsubsection Modula-2 Types | |
11534 | @cindex Modula-2 types | |
11535 | ||
11536 | Currently @value{GDBN} can print the following data types in Modula-2 | |
11537 | syntax: array types, record types, set types, pointer types, procedure | |
11538 | types, enumerated types, subrange types and base types. You can also | |
11539 | print the contents of variables declared using these type. | |
11540 | This section gives a number of simple source code examples together with | |
11541 | sample @value{GDBN} sessions. | |
11542 | ||
11543 | The first example contains the following section of code: | |
11544 | ||
11545 | @smallexample | |
11546 | VAR | |
11547 | s: SET OF CHAR ; | |
11548 | r: [20..40] ; | |
11549 | @end smallexample | |
11550 | ||
11551 | @noindent | |
11552 | and you can request @value{GDBN} to interrogate the type and value of | |
11553 | @code{r} and @code{s}. | |
11554 | ||
11555 | @smallexample | |
11556 | (@value{GDBP}) print s | |
11557 | @{'A'..'C', 'Z'@} | |
11558 | (@value{GDBP}) ptype s | |
11559 | SET OF CHAR | |
11560 | (@value{GDBP}) print r | |
11561 | 21 | |
11562 | (@value{GDBP}) ptype r | |
11563 | [20..40] | |
11564 | @end smallexample | |
11565 | ||
11566 | @noindent | |
11567 | Likewise if your source code declares @code{s} as: | |
11568 | ||
11569 | @smallexample | |
11570 | VAR | |
11571 | s: SET ['A'..'Z'] ; | |
11572 | @end smallexample | |
11573 | ||
11574 | @noindent | |
11575 | then you may query the type of @code{s} by: | |
11576 | ||
11577 | @smallexample | |
11578 | (@value{GDBP}) ptype s | |
11579 | type = SET ['A'..'Z'] | |
11580 | @end smallexample | |
11581 | ||
11582 | @noindent | |
11583 | Note that at present you cannot interactively manipulate set | |
11584 | expressions using the debugger. | |
11585 | ||
11586 | The following example shows how you might declare an array in Modula-2 | |
11587 | and how you can interact with @value{GDBN} to print its type and contents: | |
11588 | ||
11589 | @smallexample | |
11590 | VAR | |
11591 | s: ARRAY [-10..10] OF CHAR ; | |
11592 | @end smallexample | |
11593 | ||
11594 | @smallexample | |
11595 | (@value{GDBP}) ptype s | |
11596 | ARRAY [-10..10] OF CHAR | |
11597 | @end smallexample | |
11598 | ||
11599 | Note that the array handling is not yet complete and although the type | |
11600 | is printed correctly, expression handling still assumes that all | |
11601 | arrays have a lower bound of zero and not @code{-10} as in the example | |
844781a1 | 11602 | above. |
72019c9c GM |
11603 | |
11604 | Here are some more type related Modula-2 examples: | |
11605 | ||
11606 | @smallexample | |
11607 | TYPE | |
11608 | colour = (blue, red, yellow, green) ; | |
11609 | t = [blue..yellow] ; | |
11610 | VAR | |
11611 | s: t ; | |
11612 | BEGIN | |
11613 | s := blue ; | |
11614 | @end smallexample | |
11615 | ||
11616 | @noindent | |
11617 | The @value{GDBN} interaction shows how you can query the data type | |
11618 | and value of a variable. | |
11619 | ||
11620 | @smallexample | |
11621 | (@value{GDBP}) print s | |
11622 | $1 = blue | |
11623 | (@value{GDBP}) ptype t | |
11624 | type = [blue..yellow] | |
11625 | @end smallexample | |
11626 | ||
11627 | @noindent | |
11628 | In this example a Modula-2 array is declared and its contents | |
11629 | displayed. Observe that the contents are written in the same way as | |
11630 | their @code{C} counterparts. | |
11631 | ||
11632 | @smallexample | |
11633 | VAR | |
11634 | s: ARRAY [1..5] OF CARDINAL ; | |
11635 | BEGIN | |
11636 | s[1] := 1 ; | |
11637 | @end smallexample | |
11638 | ||
11639 | @smallexample | |
11640 | (@value{GDBP}) print s | |
11641 | $1 = @{1, 0, 0, 0, 0@} | |
11642 | (@value{GDBP}) ptype s | |
11643 | type = ARRAY [1..5] OF CARDINAL | |
11644 | @end smallexample | |
11645 | ||
11646 | The Modula-2 language interface to @value{GDBN} also understands | |
11647 | pointer types as shown in this example: | |
11648 | ||
11649 | @smallexample | |
11650 | VAR | |
11651 | s: POINTER TO ARRAY [1..5] OF CARDINAL ; | |
11652 | BEGIN | |
11653 | NEW(s) ; | |
11654 | s^[1] := 1 ; | |
11655 | @end smallexample | |
11656 | ||
11657 | @noindent | |
11658 | and you can request that @value{GDBN} describes the type of @code{s}. | |
11659 | ||
11660 | @smallexample | |
11661 | (@value{GDBP}) ptype s | |
11662 | type = POINTER TO ARRAY [1..5] OF CARDINAL | |
11663 | @end smallexample | |
11664 | ||
11665 | @value{GDBN} handles compound types as we can see in this example. | |
11666 | Here we combine array types, record types, pointer types and subrange | |
11667 | types: | |
11668 | ||
11669 | @smallexample | |
11670 | TYPE | |
11671 | foo = RECORD | |
11672 | f1: CARDINAL ; | |
11673 | f2: CHAR ; | |
11674 | f3: myarray ; | |
11675 | END ; | |
11676 | ||
11677 | myarray = ARRAY myrange OF CARDINAL ; | |
11678 | myrange = [-2..2] ; | |
11679 | VAR | |
11680 | s: POINTER TO ARRAY myrange OF foo ; | |
11681 | @end smallexample | |
11682 | ||
11683 | @noindent | |
11684 | and you can ask @value{GDBN} to describe the type of @code{s} as shown | |
11685 | below. | |
11686 | ||
11687 | @smallexample | |
11688 | (@value{GDBP}) ptype s | |
11689 | type = POINTER TO ARRAY [-2..2] OF foo = RECORD | |
11690 | f1 : CARDINAL; | |
11691 | f2 : CHAR; | |
11692 | f3 : ARRAY [-2..2] OF CARDINAL; | |
11693 | END | |
11694 | @end smallexample | |
11695 | ||
6d2ebf8b | 11696 | @node M2 Defaults |
79a6e687 | 11697 | @subsubsection Modula-2 Defaults |
c906108c SS |
11698 | @cindex Modula-2 defaults |
11699 | ||
11700 | If type and range checking are set automatically by @value{GDBN}, they | |
11701 | both default to @code{on} whenever the working language changes to | |
d4f3574e | 11702 | Modula-2. This happens regardless of whether you or @value{GDBN} |
c906108c SS |
11703 | selected the working language. |
11704 | ||
11705 | If you allow @value{GDBN} to set the language automatically, then entering | |
11706 | code compiled from a file whose name ends with @file{.mod} sets the | |
79a6e687 BW |
11707 | working language to Modula-2. @xref{Automatically, ,Having @value{GDBN} |
11708 | Infer the Source Language}, for further details. | |
c906108c | 11709 | |
6d2ebf8b | 11710 | @node Deviations |
79a6e687 | 11711 | @subsubsection Deviations from Standard Modula-2 |
c906108c SS |
11712 | @cindex Modula-2, deviations from |
11713 | ||
11714 | A few changes have been made to make Modula-2 programs easier to debug. | |
11715 | This is done primarily via loosening its type strictness: | |
11716 | ||
11717 | @itemize @bullet | |
11718 | @item | |
11719 | Unlike in standard Modula-2, pointer constants can be formed by | |
11720 | integers. This allows you to modify pointer variables during | |
11721 | debugging. (In standard Modula-2, the actual address contained in a | |
11722 | pointer variable is hidden from you; it can only be modified | |
11723 | through direct assignment to another pointer variable or expression that | |
11724 | returned a pointer.) | |
11725 | ||
11726 | @item | |
11727 | C escape sequences can be used in strings and characters to represent | |
11728 | non-printable characters. @value{GDBN} prints out strings with these | |
11729 | escape sequences embedded. Single non-printable characters are | |
11730 | printed using the @samp{CHR(@var{nnn})} format. | |
11731 | ||
11732 | @item | |
11733 | The assignment operator (@code{:=}) returns the value of its right-hand | |
11734 | argument. | |
11735 | ||
11736 | @item | |
11737 | All built-in procedures both modify @emph{and} return their argument. | |
11738 | @end itemize | |
11739 | ||
6d2ebf8b | 11740 | @node M2 Checks |
79a6e687 | 11741 | @subsubsection Modula-2 Type and Range Checks |
c906108c SS |
11742 | @cindex Modula-2 checks |
11743 | ||
11744 | @quotation | |
11745 | @emph{Warning:} in this release, @value{GDBN} does not yet perform type or | |
11746 | range checking. | |
11747 | @end quotation | |
11748 | @c FIXME remove warning when type/range checks added | |
11749 | ||
11750 | @value{GDBN} considers two Modula-2 variables type equivalent if: | |
11751 | ||
11752 | @itemize @bullet | |
11753 | @item | |
11754 | They are of types that have been declared equivalent via a @code{TYPE | |
11755 | @var{t1} = @var{t2}} statement | |
11756 | ||
11757 | @item | |
11758 | They have been declared on the same line. (Note: This is true of the | |
11759 | @sc{gnu} Modula-2 compiler, but it may not be true of other compilers.) | |
11760 | @end itemize | |
11761 | ||
11762 | As long as type checking is enabled, any attempt to combine variables | |
11763 | whose types are not equivalent is an error. | |
11764 | ||
11765 | Range checking is done on all mathematical operations, assignment, array | |
11766 | index bounds, and all built-in functions and procedures. | |
11767 | ||
6d2ebf8b | 11768 | @node M2 Scope |
79a6e687 | 11769 | @subsubsection The Scope Operators @code{::} and @code{.} |
c906108c | 11770 | @cindex scope |
41afff9a | 11771 | @cindex @code{.}, Modula-2 scope operator |
c906108c SS |
11772 | @cindex colon, doubled as scope operator |
11773 | @ifinfo | |
41afff9a | 11774 | @vindex colon-colon@r{, in Modula-2} |
c906108c SS |
11775 | @c Info cannot handle :: but TeX can. |
11776 | @end ifinfo | |
a67ec3f4 | 11777 | @ifnotinfo |
41afff9a | 11778 | @vindex ::@r{, in Modula-2} |
a67ec3f4 | 11779 | @end ifnotinfo |
c906108c SS |
11780 | |
11781 | There are a few subtle differences between the Modula-2 scope operator | |
11782 | (@code{.}) and the @value{GDBN} scope operator (@code{::}). The two have | |
11783 | similar syntax: | |
11784 | ||
474c8240 | 11785 | @smallexample |
c906108c SS |
11786 | |
11787 | @var{module} . @var{id} | |
11788 | @var{scope} :: @var{id} | |
474c8240 | 11789 | @end smallexample |
c906108c SS |
11790 | |
11791 | @noindent | |
11792 | where @var{scope} is the name of a module or a procedure, | |
11793 | @var{module} the name of a module, and @var{id} is any declared | |
11794 | identifier within your program, except another module. | |
11795 | ||
11796 | Using the @code{::} operator makes @value{GDBN} search the scope | |
11797 | specified by @var{scope} for the identifier @var{id}. If it is not | |
11798 | found in the specified scope, then @value{GDBN} searches all scopes | |
11799 | enclosing the one specified by @var{scope}. | |
11800 | ||
11801 | Using the @code{.} operator makes @value{GDBN} search the current scope for | |
11802 | the identifier specified by @var{id} that was imported from the | |
11803 | definition module specified by @var{module}. With this operator, it is | |
11804 | an error if the identifier @var{id} was not imported from definition | |
11805 | module @var{module}, or if @var{id} is not an identifier in | |
11806 | @var{module}. | |
11807 | ||
6d2ebf8b | 11808 | @node GDB/M2 |
c906108c SS |
11809 | @subsubsection @value{GDBN} and Modula-2 |
11810 | ||
11811 | Some @value{GDBN} commands have little use when debugging Modula-2 programs. | |
11812 | Five subcommands of @code{set print} and @code{show print} apply | |
b37052ae | 11813 | specifically to C and C@t{++}: @samp{vtbl}, @samp{demangle}, |
c906108c | 11814 | @samp{asm-demangle}, @samp{object}, and @samp{union}. The first four |
b37052ae | 11815 | apply to C@t{++}, and the last to the C @code{union} type, which has no direct |
c906108c SS |
11816 | analogue in Modula-2. |
11817 | ||
11818 | The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available | |
d4f3574e | 11819 | with any language, is not useful with Modula-2. Its |
c906108c | 11820 | intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be |
b37052ae | 11821 | created in Modula-2 as they can in C or C@t{++}. However, because an |
c906108c | 11822 | address can be specified by an integral constant, the construct |
d4f3574e | 11823 | @samp{@{@var{type}@}@var{adrexp}} is still useful. |
c906108c SS |
11824 | |
11825 | @cindex @code{#} in Modula-2 | |
11826 | In @value{GDBN} scripts, the Modula-2 inequality operator @code{#} is | |
11827 | interpreted as the beginning of a comment. Use @code{<>} instead. | |
c906108c | 11828 | |
e07c999f PH |
11829 | @node Ada |
11830 | @subsection Ada | |
11831 | @cindex Ada | |
11832 | ||
11833 | The extensions made to @value{GDBN} for Ada only support | |
11834 | output from the @sc{gnu} Ada (GNAT) compiler. | |
11835 | Other Ada compilers are not currently supported, and | |
11836 | attempting to debug executables produced by them is most likely | |
11837 | to be difficult. | |
11838 | ||
11839 | ||
11840 | @cindex expressions in Ada | |
11841 | @menu | |
11842 | * Ada Mode Intro:: General remarks on the Ada syntax | |
11843 | and semantics supported by Ada mode | |
11844 | in @value{GDBN}. | |
11845 | * Omissions from Ada:: Restrictions on the Ada expression syntax. | |
11846 | * Additions to Ada:: Extensions of the Ada expression syntax. | |
11847 | * Stopping Before Main Program:: Debugging the program during elaboration. | |
20924a55 JB |
11848 | * Ada Tasks:: Listing and setting breakpoints in tasks. |
11849 | * Ada Tasks and Core Files:: Tasking Support when Debugging Core Files | |
e07c999f PH |
11850 | * Ada Glitches:: Known peculiarities of Ada mode. |
11851 | @end menu | |
11852 | ||
11853 | @node Ada Mode Intro | |
11854 | @subsubsection Introduction | |
11855 | @cindex Ada mode, general | |
11856 | ||
11857 | The Ada mode of @value{GDBN} supports a fairly large subset of Ada expression | |
11858 | syntax, with some extensions. | |
11859 | The philosophy behind the design of this subset is | |
11860 | ||
11861 | @itemize @bullet | |
11862 | @item | |
11863 | That @value{GDBN} should provide basic literals and access to operations for | |
11864 | arithmetic, dereferencing, field selection, indexing, and subprogram calls, | |
11865 | leaving more sophisticated computations to subprograms written into the | |
11866 | program (which therefore may be called from @value{GDBN}). | |
11867 | ||
11868 | @item | |
11869 | That type safety and strict adherence to Ada language restrictions | |
11870 | are not particularly important to the @value{GDBN} user. | |
11871 | ||
11872 | @item | |
11873 | That brevity is important to the @value{GDBN} user. | |
11874 | @end itemize | |
11875 | ||
f3a2dd1a JB |
11876 | Thus, for brevity, the debugger acts as if all names declared in |
11877 | user-written packages are directly visible, even if they are not visible | |
11878 | according to Ada rules, thus making it unnecessary to fully qualify most | |
11879 | names with their packages, regardless of context. Where this causes | |
11880 | ambiguity, @value{GDBN} asks the user's intent. | |
e07c999f PH |
11881 | |
11882 | The debugger will start in Ada mode if it detects an Ada main program. | |
11883 | As for other languages, it will enter Ada mode when stopped in a program that | |
11884 | was translated from an Ada source file. | |
11885 | ||
11886 | While in Ada mode, you may use `@t{--}' for comments. This is useful | |
11887 | mostly for documenting command files. The standard @value{GDBN} comment | |
11888 | (@samp{#}) still works at the beginning of a line in Ada mode, but not in the | |
11889 | middle (to allow based literals). | |
11890 | ||
11891 | The debugger supports limited overloading. Given a subprogram call in which | |
11892 | the function symbol has multiple definitions, it will use the number of | |
11893 | actual parameters and some information about their types to attempt to narrow | |
11894 | the set of definitions. It also makes very limited use of context, preferring | |
11895 | procedures to functions in the context of the @code{call} command, and | |
11896 | functions to procedures elsewhere. | |
11897 | ||
11898 | @node Omissions from Ada | |
11899 | @subsubsection Omissions from Ada | |
11900 | @cindex Ada, omissions from | |
11901 | ||
11902 | Here are the notable omissions from the subset: | |
11903 | ||
11904 | @itemize @bullet | |
11905 | @item | |
11906 | Only a subset of the attributes are supported: | |
11907 | ||
11908 | @itemize @minus | |
11909 | @item | |
11910 | @t{'First}, @t{'Last}, and @t{'Length} | |
11911 | on array objects (not on types and subtypes). | |
11912 | ||
11913 | @item | |
11914 | @t{'Min} and @t{'Max}. | |
11915 | ||
11916 | @item | |
11917 | @t{'Pos} and @t{'Val}. | |
11918 | ||
11919 | @item | |
11920 | @t{'Tag}. | |
11921 | ||
11922 | @item | |
11923 | @t{'Range} on array objects (not subtypes), but only as the right | |
11924 | operand of the membership (@code{in}) operator. | |
11925 | ||
11926 | @item | |
11927 | @t{'Access}, @t{'Unchecked_Access}, and | |
11928 | @t{'Unrestricted_Access} (a GNAT extension). | |
11929 | ||
11930 | @item | |
11931 | @t{'Address}. | |
11932 | @end itemize | |
11933 | ||
11934 | @item | |
11935 | The names in | |
11936 | @code{Characters.Latin_1} are not available and | |
11937 | concatenation is not implemented. Thus, escape characters in strings are | |
11938 | not currently available. | |
11939 | ||
11940 | @item | |
11941 | Equality tests (@samp{=} and @samp{/=}) on arrays test for bitwise | |
11942 | equality of representations. They will generally work correctly | |
11943 | for strings and arrays whose elements have integer or enumeration types. | |
11944 | They may not work correctly for arrays whose element | |
11945 | types have user-defined equality, for arrays of real values | |
11946 | (in particular, IEEE-conformant floating point, because of negative | |
11947 | zeroes and NaNs), and for arrays whose elements contain unused bits with | |
11948 | indeterminate values. | |
11949 | ||
11950 | @item | |
11951 | The other component-by-component array operations (@code{and}, @code{or}, | |
11952 | @code{xor}, @code{not}, and relational tests other than equality) | |
11953 | are not implemented. | |
11954 | ||
11955 | @item | |
860701dc PH |
11956 | @cindex array aggregates (Ada) |
11957 | @cindex record aggregates (Ada) | |
11958 | @cindex aggregates (Ada) | |
11959 | There is limited support for array and record aggregates. They are | |
11960 | permitted only on the right sides of assignments, as in these examples: | |
11961 | ||
11962 | @smallexample | |
077e0a52 JB |
11963 | (@value{GDBP}) set An_Array := (1, 2, 3, 4, 5, 6) |
11964 | (@value{GDBP}) set An_Array := (1, others => 0) | |
11965 | (@value{GDBP}) set An_Array := (0|4 => 1, 1..3 => 2, 5 => 6) | |
11966 | (@value{GDBP}) set A_2D_Array := ((1, 2, 3), (4, 5, 6), (7, 8, 9)) | |
11967 | (@value{GDBP}) set A_Record := (1, "Peter", True); | |
11968 | (@value{GDBP}) set A_Record := (Name => "Peter", Id => 1, Alive => True) | |
860701dc PH |
11969 | @end smallexample |
11970 | ||
11971 | Changing a | |
11972 | discriminant's value by assigning an aggregate has an | |
11973 | undefined effect if that discriminant is used within the record. | |
11974 | However, you can first modify discriminants by directly assigning to | |
11975 | them (which normally would not be allowed in Ada), and then performing an | |
11976 | aggregate assignment. For example, given a variable @code{A_Rec} | |
11977 | declared to have a type such as: | |
11978 | ||
11979 | @smallexample | |
11980 | type Rec (Len : Small_Integer := 0) is record | |
11981 | Id : Integer; | |
11982 | Vals : IntArray (1 .. Len); | |
11983 | end record; | |
11984 | @end smallexample | |
11985 | ||
11986 | you can assign a value with a different size of @code{Vals} with two | |
11987 | assignments: | |
11988 | ||
11989 | @smallexample | |
077e0a52 JB |
11990 | (@value{GDBP}) set A_Rec.Len := 4 |
11991 | (@value{GDBP}) set A_Rec := (Id => 42, Vals => (1, 2, 3, 4)) | |
860701dc PH |
11992 | @end smallexample |
11993 | ||
11994 | As this example also illustrates, @value{GDBN} is very loose about the usual | |
11995 | rules concerning aggregates. You may leave out some of the | |
11996 | components of an array or record aggregate (such as the @code{Len} | |
11997 | component in the assignment to @code{A_Rec} above); they will retain their | |
11998 | original values upon assignment. You may freely use dynamic values as | |
11999 | indices in component associations. You may even use overlapping or | |
12000 | redundant component associations, although which component values are | |
12001 | assigned in such cases is not defined. | |
e07c999f PH |
12002 | |
12003 | @item | |
12004 | Calls to dispatching subprograms are not implemented. | |
12005 | ||
12006 | @item | |
12007 | The overloading algorithm is much more limited (i.e., less selective) | |
ae21e955 BW |
12008 | than that of real Ada. It makes only limited use of the context in |
12009 | which a subexpression appears to resolve its meaning, and it is much | |
12010 | looser in its rules for allowing type matches. As a result, some | |
12011 | function calls will be ambiguous, and the user will be asked to choose | |
12012 | the proper resolution. | |
e07c999f PH |
12013 | |
12014 | @item | |
12015 | The @code{new} operator is not implemented. | |
12016 | ||
12017 | @item | |
12018 | Entry calls are not implemented. | |
12019 | ||
12020 | @item | |
12021 | Aside from printing, arithmetic operations on the native VAX floating-point | |
12022 | formats are not supported. | |
12023 | ||
12024 | @item | |
12025 | It is not possible to slice a packed array. | |
158c7665 PH |
12026 | |
12027 | @item | |
12028 | The names @code{True} and @code{False}, when not part of a qualified name, | |
12029 | are interpreted as if implicitly prefixed by @code{Standard}, regardless of | |
12030 | context. | |
12031 | Should your program | |
12032 | redefine these names in a package or procedure (at best a dubious practice), | |
12033 | you will have to use fully qualified names to access their new definitions. | |
e07c999f PH |
12034 | @end itemize |
12035 | ||
12036 | @node Additions to Ada | |
12037 | @subsubsection Additions to Ada | |
12038 | @cindex Ada, deviations from | |
12039 | ||
12040 | As it does for other languages, @value{GDBN} makes certain generic | |
12041 | extensions to Ada (@pxref{Expressions}): | |
12042 | ||
12043 | @itemize @bullet | |
12044 | @item | |
ae21e955 BW |
12045 | If the expression @var{E} is a variable residing in memory (typically |
12046 | a local variable or array element) and @var{N} is a positive integer, | |
12047 | then @code{@var{E}@@@var{N}} displays the values of @var{E} and the | |
12048 | @var{N}-1 adjacent variables following it in memory as an array. In | |
12049 | Ada, this operator is generally not necessary, since its prime use is | |
12050 | in displaying parts of an array, and slicing will usually do this in | |
12051 | Ada. However, there are occasional uses when debugging programs in | |
12052 | which certain debugging information has been optimized away. | |
e07c999f PH |
12053 | |
12054 | @item | |
ae21e955 BW |
12055 | @code{@var{B}::@var{var}} means ``the variable named @var{var} that |
12056 | appears in function or file @var{B}.'' When @var{B} is a file name, | |
12057 | you must typically surround it in single quotes. | |
e07c999f PH |
12058 | |
12059 | @item | |
12060 | The expression @code{@{@var{type}@} @var{addr}} means ``the variable of type | |
12061 | @var{type} that appears at address @var{addr}.'' | |
12062 | ||
12063 | @item | |
12064 | A name starting with @samp{$} is a convenience variable | |
12065 | (@pxref{Convenience Vars}) or a machine register (@pxref{Registers}). | |
12066 | @end itemize | |
12067 | ||
ae21e955 BW |
12068 | In addition, @value{GDBN} provides a few other shortcuts and outright |
12069 | additions specific to Ada: | |
e07c999f PH |
12070 | |
12071 | @itemize @bullet | |
12072 | @item | |
12073 | The assignment statement is allowed as an expression, returning | |
12074 | its right-hand operand as its value. Thus, you may enter | |
12075 | ||
12076 | @smallexample | |
077e0a52 JB |
12077 | (@value{GDBP}) set x := y + 3 |
12078 | (@value{GDBP}) print A(tmp := y + 1) | |
e07c999f PH |
12079 | @end smallexample |
12080 | ||
12081 | @item | |
12082 | The semicolon is allowed as an ``operator,'' returning as its value | |
12083 | the value of its right-hand operand. | |
12084 | This allows, for example, | |
12085 | complex conditional breaks: | |
12086 | ||
12087 | @smallexample | |
077e0a52 JB |
12088 | (@value{GDBP}) break f |
12089 | (@value{GDBP}) condition 1 (report(i); k += 1; A(k) > 100) | |
e07c999f PH |
12090 | @end smallexample |
12091 | ||
12092 | @item | |
12093 | Rather than use catenation and symbolic character names to introduce special | |
12094 | characters into strings, one may instead use a special bracket notation, | |
12095 | which is also used to print strings. A sequence of characters of the form | |
12096 | @samp{["@var{XX}"]} within a string or character literal denotes the | |
12097 | (single) character whose numeric encoding is @var{XX} in hexadecimal. The | |
12098 | sequence of characters @samp{["""]} also denotes a single quotation mark | |
12099 | in strings. For example, | |
12100 | @smallexample | |
12101 | "One line.["0a"]Next line.["0a"]" | |
12102 | @end smallexample | |
12103 | @noindent | |
ae21e955 BW |
12104 | contains an ASCII newline character (@code{Ada.Characters.Latin_1.LF}) |
12105 | after each period. | |
e07c999f PH |
12106 | |
12107 | @item | |
12108 | The subtype used as a prefix for the attributes @t{'Pos}, @t{'Min}, and | |
12109 | @t{'Max} is optional (and is ignored in any case). For example, it is valid | |
12110 | to write | |
12111 | ||
12112 | @smallexample | |
077e0a52 | 12113 | (@value{GDBP}) print 'max(x, y) |
e07c999f PH |
12114 | @end smallexample |
12115 | ||
12116 | @item | |
12117 | When printing arrays, @value{GDBN} uses positional notation when the | |
12118 | array has a lower bound of 1, and uses a modified named notation otherwise. | |
ae21e955 BW |
12119 | For example, a one-dimensional array of three integers with a lower bound |
12120 | of 3 might print as | |
e07c999f PH |
12121 | |
12122 | @smallexample | |
12123 | (3 => 10, 17, 1) | |
12124 | @end smallexample | |
12125 | ||
12126 | @noindent | |
12127 | That is, in contrast to valid Ada, only the first component has a @code{=>} | |
12128 | clause. | |
12129 | ||
12130 | @item | |
12131 | You may abbreviate attributes in expressions with any unique, | |
12132 | multi-character subsequence of | |
12133 | their names (an exact match gets preference). | |
12134 | For example, you may use @t{a'len}, @t{a'gth}, or @t{a'lh} | |
12135 | in place of @t{a'length}. | |
12136 | ||
12137 | @item | |
12138 | @cindex quoting Ada internal identifiers | |
12139 | Since Ada is case-insensitive, the debugger normally maps identifiers you type | |
12140 | to lower case. The GNAT compiler uses upper-case characters for | |
12141 | some of its internal identifiers, which are normally of no interest to users. | |
12142 | For the rare occasions when you actually have to look at them, | |
12143 | enclose them in angle brackets to avoid the lower-case mapping. | |
12144 | For example, | |
12145 | @smallexample | |
077e0a52 | 12146 | (@value{GDBP}) print <JMPBUF_SAVE>[0] |
e07c999f PH |
12147 | @end smallexample |
12148 | ||
12149 | @item | |
12150 | Printing an object of class-wide type or dereferencing an | |
12151 | access-to-class-wide value will display all the components of the object's | |
12152 | specific type (as indicated by its run-time tag). Likewise, component | |
12153 | selection on such a value will operate on the specific type of the | |
12154 | object. | |
12155 | ||
12156 | @end itemize | |
12157 | ||
12158 | @node Stopping Before Main Program | |
12159 | @subsubsection Stopping at the Very Beginning | |
12160 | ||
12161 | @cindex breakpointing Ada elaboration code | |
12162 | It is sometimes necessary to debug the program during elaboration, and | |
12163 | before reaching the main procedure. | |
12164 | As defined in the Ada Reference | |
12165 | Manual, the elaboration code is invoked from a procedure called | |
12166 | @code{adainit}. To run your program up to the beginning of | |
12167 | elaboration, simply use the following two commands: | |
12168 | @code{tbreak adainit} and @code{run}. | |
12169 | ||
20924a55 JB |
12170 | @node Ada Tasks |
12171 | @subsubsection Extensions for Ada Tasks | |
12172 | @cindex Ada, tasking | |
12173 | ||
12174 | Support for Ada tasks is analogous to that for threads (@pxref{Threads}). | |
12175 | @value{GDBN} provides the following task-related commands: | |
12176 | ||
12177 | @table @code | |
12178 | @kindex info tasks | |
12179 | @item info tasks | |
12180 | This command shows a list of current Ada tasks, as in the following example: | |
12181 | ||
12182 | ||
12183 | @smallexample | |
12184 | @iftex | |
12185 | @leftskip=0.5cm | |
12186 | @end iftex | |
12187 | (@value{GDBP}) info tasks | |
12188 | ID TID P-ID Pri State Name | |
12189 | 1 8088000 0 15 Child Activation Wait main_task | |
12190 | 2 80a4000 1 15 Accept Statement b | |
12191 | 3 809a800 1 15 Child Activation Wait a | |
32cd1edc | 12192 | * 4 80ae800 3 15 Runnable c |
20924a55 JB |
12193 | |
12194 | @end smallexample | |
12195 | ||
12196 | @noindent | |
12197 | In this listing, the asterisk before the last task indicates it to be the | |
12198 | task currently being inspected. | |
12199 | ||
12200 | @table @asis | |
12201 | @item ID | |
12202 | Represents @value{GDBN}'s internal task number. | |
12203 | ||
12204 | @item TID | |
12205 | The Ada task ID. | |
12206 | ||
12207 | @item P-ID | |
12208 | The parent's task ID (@value{GDBN}'s internal task number). | |
12209 | ||
12210 | @item Pri | |
12211 | The base priority of the task. | |
12212 | ||
12213 | @item State | |
12214 | Current state of the task. | |
12215 | ||
12216 | @table @code | |
12217 | @item Unactivated | |
12218 | The task has been created but has not been activated. It cannot be | |
12219 | executing. | |
12220 | ||
20924a55 JB |
12221 | @item Runnable |
12222 | The task is not blocked for any reason known to Ada. (It may be waiting | |
12223 | for a mutex, though.) It is conceptually "executing" in normal mode. | |
12224 | ||
12225 | @item Terminated | |
12226 | The task is terminated, in the sense of ARM 9.3 (5). Any dependents | |
12227 | that were waiting on terminate alternatives have been awakened and have | |
12228 | terminated themselves. | |
12229 | ||
12230 | @item Child Activation Wait | |
12231 | The task is waiting for created tasks to complete activation. | |
12232 | ||
12233 | @item Accept Statement | |
12234 | The task is waiting on an accept or selective wait statement. | |
12235 | ||
12236 | @item Waiting on entry call | |
12237 | The task is waiting on an entry call. | |
12238 | ||
12239 | @item Async Select Wait | |
12240 | The task is waiting to start the abortable part of an asynchronous | |
12241 | select statement. | |
12242 | ||
12243 | @item Delay Sleep | |
12244 | The task is waiting on a select statement with only a delay | |
12245 | alternative open. | |
12246 | ||
12247 | @item Child Termination Wait | |
12248 | The task is sleeping having completed a master within itself, and is | |
12249 | waiting for the tasks dependent on that master to become terminated or | |
12250 | waiting on a terminate Phase. | |
12251 | ||
12252 | @item Wait Child in Term Alt | |
12253 | The task is sleeping waiting for tasks on terminate alternatives to | |
12254 | finish terminating. | |
12255 | ||
12256 | @item Accepting RV with @var{taskno} | |
12257 | The task is accepting a rendez-vous with the task @var{taskno}. | |
12258 | @end table | |
12259 | ||
12260 | @item Name | |
12261 | Name of the task in the program. | |
12262 | ||
12263 | @end table | |
12264 | ||
12265 | @kindex info task @var{taskno} | |
12266 | @item info task @var{taskno} | |
12267 | This command shows detailled informations on the specified task, as in | |
12268 | the following example: | |
12269 | @smallexample | |
12270 | @iftex | |
12271 | @leftskip=0.5cm | |
12272 | @end iftex | |
12273 | (@value{GDBP}) info tasks | |
12274 | ID TID P-ID Pri State Name | |
12275 | 1 8077880 0 15 Child Activation Wait main_task | |
32cd1edc | 12276 | * 2 807c468 1 15 Runnable task_1 |
20924a55 JB |
12277 | (@value{GDBP}) info task 2 |
12278 | Ada Task: 0x807c468 | |
12279 | Name: task_1 | |
12280 | Thread: 0x807f378 | |
12281 | Parent: 1 (main_task) | |
12282 | Base Priority: 15 | |
12283 | State: Runnable | |
12284 | @end smallexample | |
12285 | ||
12286 | @item task | |
12287 | @kindex task@r{ (Ada)} | |
12288 | @cindex current Ada task ID | |
12289 | This command prints the ID of the current task. | |
12290 | ||
12291 | @smallexample | |
12292 | @iftex | |
12293 | @leftskip=0.5cm | |
12294 | @end iftex | |
12295 | (@value{GDBP}) info tasks | |
12296 | ID TID P-ID Pri State Name | |
12297 | 1 8077870 0 15 Child Activation Wait main_task | |
32cd1edc | 12298 | * 2 807c458 1 15 Runnable t |
20924a55 JB |
12299 | (@value{GDBP}) task |
12300 | [Current task is 2] | |
12301 | @end smallexample | |
12302 | ||
12303 | @item task @var{taskno} | |
12304 | @cindex Ada task switching | |
12305 | This command is like the @code{thread @var{threadno}} | |
12306 | command (@pxref{Threads}). It switches the context of debugging | |
12307 | from the current task to the given task. | |
12308 | ||
12309 | @smallexample | |
12310 | @iftex | |
12311 | @leftskip=0.5cm | |
12312 | @end iftex | |
12313 | (@value{GDBP}) info tasks | |
12314 | ID TID P-ID Pri State Name | |
12315 | 1 8077870 0 15 Child Activation Wait main_task | |
32cd1edc | 12316 | * 2 807c458 1 15 Runnable t |
20924a55 JB |
12317 | (@value{GDBP}) task 1 |
12318 | [Switching to task 1] | |
12319 | #0 0x8067726 in pthread_cond_wait () | |
12320 | (@value{GDBP}) bt | |
12321 | #0 0x8067726 in pthread_cond_wait () | |
12322 | #1 0x8056714 in system.os_interface.pthread_cond_wait () | |
12323 | #2 0x805cb63 in system.task_primitives.operations.sleep () | |
12324 | #3 0x806153e in system.tasking.stages.activate_tasks () | |
12325 | #4 0x804aacc in un () at un.adb:5 | |
12326 | @end smallexample | |
12327 | ||
45ac276d JB |
12328 | @item break @var{linespec} task @var{taskno} |
12329 | @itemx break @var{linespec} task @var{taskno} if @dots{} | |
12330 | @cindex breakpoints and tasks, in Ada | |
12331 | @cindex task breakpoints, in Ada | |
12332 | @kindex break @dots{} task @var{taskno}@r{ (Ada)} | |
12333 | These commands are like the @code{break @dots{} thread @dots{}} | |
12334 | command (@pxref{Thread Stops}). | |
12335 | @var{linespec} specifies source lines, as described | |
12336 | in @ref{Specify Location}. | |
12337 | ||
12338 | Use the qualifier @samp{task @var{taskno}} with a breakpoint command | |
12339 | to specify that you only want @value{GDBN} to stop the program when a | |
12340 | particular Ada task reaches this breakpoint. @var{taskno} is one of the | |
12341 | numeric task identifiers assigned by @value{GDBN}, shown in the first | |
12342 | column of the @samp{info tasks} display. | |
12343 | ||
12344 | If you do not specify @samp{task @var{taskno}} when you set a | |
12345 | breakpoint, the breakpoint applies to @emph{all} tasks of your | |
12346 | program. | |
12347 | ||
12348 | You can use the @code{task} qualifier on conditional breakpoints as | |
12349 | well; in this case, place @samp{task @var{taskno}} before the | |
12350 | breakpoint condition (before the @code{if}). | |
12351 | ||
12352 | For example, | |
12353 | ||
12354 | @smallexample | |
12355 | @iftex | |
12356 | @leftskip=0.5cm | |
12357 | @end iftex | |
12358 | (@value{GDBP}) info tasks | |
12359 | ID TID P-ID Pri State Name | |
12360 | 1 140022020 0 15 Child Activation Wait main_task | |
12361 | 2 140045060 1 15 Accept/Select Wait t2 | |
12362 | 3 140044840 1 15 Runnable t1 | |
12363 | * 4 140056040 1 15 Runnable t3 | |
12364 | (@value{GDBP}) b 15 task 2 | |
12365 | Breakpoint 5 at 0x120044cb0: file test_task_debug.adb, line 15. | |
12366 | (@value{GDBP}) cont | |
12367 | Continuing. | |
12368 | task # 1 running | |
12369 | task # 2 running | |
12370 | ||
12371 | Breakpoint 5, test_task_debug () at test_task_debug.adb:15 | |
12372 | 15 flush; | |
12373 | (@value{GDBP}) info tasks | |
12374 | ID TID P-ID Pri State Name | |
12375 | 1 140022020 0 15 Child Activation Wait main_task | |
12376 | * 2 140045060 1 15 Runnable t2 | |
12377 | 3 140044840 1 15 Runnable t1 | |
12378 | 4 140056040 1 15 Delay Sleep t3 | |
12379 | @end smallexample | |
20924a55 JB |
12380 | @end table |
12381 | ||
12382 | @node Ada Tasks and Core Files | |
12383 | @subsubsection Tasking Support when Debugging Core Files | |
12384 | @cindex Ada tasking and core file debugging | |
12385 | ||
12386 | When inspecting a core file, as opposed to debugging a live program, | |
12387 | tasking support may be limited or even unavailable, depending on | |
12388 | the platform being used. | |
12389 | For instance, on x86-linux, the list of tasks is available, but task | |
12390 | switching is not supported. On Tru64, however, task switching will work | |
12391 | as usual. | |
12392 | ||
12393 | On certain platforms, including Tru64, the debugger needs to perform some | |
12394 | memory writes in order to provide Ada tasking support. When inspecting | |
12395 | a core file, this means that the core file must be opened with read-write | |
12396 | privileges, using the command @samp{"set write on"} (@pxref{Patching}). | |
12397 | Under these circumstances, you should make a backup copy of the core | |
12398 | file before inspecting it with @value{GDBN}. | |
12399 | ||
e07c999f PH |
12400 | @node Ada Glitches |
12401 | @subsubsection Known Peculiarities of Ada Mode | |
12402 | @cindex Ada, problems | |
12403 | ||
12404 | Besides the omissions listed previously (@pxref{Omissions from Ada}), | |
12405 | we know of several problems with and limitations of Ada mode in | |
12406 | @value{GDBN}, | |
12407 | some of which will be fixed with planned future releases of the debugger | |
12408 | and the GNU Ada compiler. | |
12409 | ||
12410 | @itemize @bullet | |
12411 | @item | |
12412 | Currently, the debugger | |
12413 | has insufficient information to determine whether certain pointers represent | |
12414 | pointers to objects or the objects themselves. | |
12415 | Thus, the user may have to tack an extra @code{.all} after an expression | |
12416 | to get it printed properly. | |
12417 | ||
12418 | @item | |
12419 | Static constants that the compiler chooses not to materialize as objects in | |
12420 | storage are invisible to the debugger. | |
12421 | ||
12422 | @item | |
12423 | Named parameter associations in function argument lists are ignored (the | |
12424 | argument lists are treated as positional). | |
12425 | ||
12426 | @item | |
12427 | Many useful library packages are currently invisible to the debugger. | |
12428 | ||
12429 | @item | |
12430 | Fixed-point arithmetic, conversions, input, and output is carried out using | |
12431 | floating-point arithmetic, and may give results that only approximate those on | |
12432 | the host machine. | |
12433 | ||
e07c999f PH |
12434 | @item |
12435 | The GNAT compiler never generates the prefix @code{Standard} for any of | |
12436 | the standard symbols defined by the Ada language. @value{GDBN} knows about | |
12437 | this: it will strip the prefix from names when you use it, and will never | |
12438 | look for a name you have so qualified among local symbols, nor match against | |
12439 | symbols in other packages or subprograms. If you have | |
12440 | defined entities anywhere in your program other than parameters and | |
12441 | local variables whose simple names match names in @code{Standard}, | |
12442 | GNAT's lack of qualification here can cause confusion. When this happens, | |
12443 | you can usually resolve the confusion | |
12444 | by qualifying the problematic names with package | |
12445 | @code{Standard} explicitly. | |
12446 | @end itemize | |
12447 | ||
79a6e687 BW |
12448 | @node Unsupported Languages |
12449 | @section Unsupported Languages | |
4e562065 JB |
12450 | |
12451 | @cindex unsupported languages | |
12452 | @cindex minimal language | |
12453 | In addition to the other fully-supported programming languages, | |
12454 | @value{GDBN} also provides a pseudo-language, called @code{minimal}. | |
12455 | It does not represent a real programming language, but provides a set | |
12456 | of capabilities close to what the C or assembly languages provide. | |
12457 | This should allow most simple operations to be performed while debugging | |
12458 | an application that uses a language currently not supported by @value{GDBN}. | |
12459 | ||
12460 | If the language is set to @code{auto}, @value{GDBN} will automatically | |
12461 | select this language if the current frame corresponds to an unsupported | |
12462 | language. | |
12463 | ||
6d2ebf8b | 12464 | @node Symbols |
c906108c SS |
12465 | @chapter Examining the Symbol Table |
12466 | ||
d4f3574e | 12467 | The commands described in this chapter allow you to inquire about the |
c906108c SS |
12468 | symbols (names of variables, functions and types) defined in your |
12469 | program. This information is inherent in the text of your program and | |
12470 | does not change as your program executes. @value{GDBN} finds it in your | |
12471 | program's symbol table, in the file indicated when you started @value{GDBN} | |
79a6e687 BW |
12472 | (@pxref{File Options, ,Choosing Files}), or by one of the |
12473 | file-management commands (@pxref{Files, ,Commands to Specify Files}). | |
c906108c SS |
12474 | |
12475 | @cindex symbol names | |
12476 | @cindex names of symbols | |
12477 | @cindex quoting names | |
12478 | Occasionally, you may need to refer to symbols that contain unusual | |
12479 | characters, which @value{GDBN} ordinarily treats as word delimiters. The | |
12480 | most frequent case is in referring to static variables in other | |
79a6e687 | 12481 | source files (@pxref{Variables,,Program Variables}). File names |
c906108c SS |
12482 | are recorded in object files as debugging symbols, but @value{GDBN} would |
12483 | ordinarily parse a typical file name, like @file{foo.c}, as the three words | |
12484 | @samp{foo} @samp{.} @samp{c}. To allow @value{GDBN} to recognize | |
12485 | @samp{foo.c} as a single symbol, enclose it in single quotes; for example, | |
12486 | ||
474c8240 | 12487 | @smallexample |
c906108c | 12488 | p 'foo.c'::x |
474c8240 | 12489 | @end smallexample |
c906108c SS |
12490 | |
12491 | @noindent | |
12492 | looks up the value of @code{x} in the scope of the file @file{foo.c}. | |
12493 | ||
12494 | @table @code | |
a8f24a35 EZ |
12495 | @cindex case-insensitive symbol names |
12496 | @cindex case sensitivity in symbol names | |
12497 | @kindex set case-sensitive | |
12498 | @item set case-sensitive on | |
12499 | @itemx set case-sensitive off | |
12500 | @itemx set case-sensitive auto | |
12501 | Normally, when @value{GDBN} looks up symbols, it matches their names | |
12502 | with case sensitivity determined by the current source language. | |
12503 | Occasionally, you may wish to control that. The command @code{set | |
12504 | case-sensitive} lets you do that by specifying @code{on} for | |
12505 | case-sensitive matches or @code{off} for case-insensitive ones. If | |
12506 | you specify @code{auto}, case sensitivity is reset to the default | |
12507 | suitable for the source language. The default is case-sensitive | |
12508 | matches for all languages except for Fortran, for which the default is | |
12509 | case-insensitive matches. | |
12510 | ||
9c16f35a EZ |
12511 | @kindex show case-sensitive |
12512 | @item show case-sensitive | |
a8f24a35 EZ |
12513 | This command shows the current setting of case sensitivity for symbols |
12514 | lookups. | |
12515 | ||
c906108c | 12516 | @kindex info address |
b37052ae | 12517 | @cindex address of a symbol |
c906108c SS |
12518 | @item info address @var{symbol} |
12519 | Describe where the data for @var{symbol} is stored. For a register | |
12520 | variable, this says which register it is kept in. For a non-register | |
12521 | local variable, this prints the stack-frame offset at which the variable | |
12522 | is always stored. | |
12523 | ||
12524 | Note the contrast with @samp{print &@var{symbol}}, which does not work | |
12525 | at all for a register variable, and for a stack local variable prints | |
12526 | the exact address of the current instantiation of the variable. | |
12527 | ||
3d67e040 | 12528 | @kindex info symbol |
b37052ae | 12529 | @cindex symbol from address |
9c16f35a | 12530 | @cindex closest symbol and offset for an address |
3d67e040 EZ |
12531 | @item info symbol @var{addr} |
12532 | Print the name of a symbol which is stored at the address @var{addr}. | |
12533 | If no symbol is stored exactly at @var{addr}, @value{GDBN} prints the | |
12534 | nearest symbol and an offset from it: | |
12535 | ||
474c8240 | 12536 | @smallexample |
3d67e040 EZ |
12537 | (@value{GDBP}) info symbol 0x54320 |
12538 | _initialize_vx + 396 in section .text | |
474c8240 | 12539 | @end smallexample |
3d67e040 EZ |
12540 | |
12541 | @noindent | |
12542 | This is the opposite of the @code{info address} command. You can use | |
12543 | it to find out the name of a variable or a function given its address. | |
12544 | ||
c14c28ba PP |
12545 | For dynamically linked executables, the name of executable or shared |
12546 | library containing the symbol is also printed: | |
12547 | ||
12548 | @smallexample | |
12549 | (@value{GDBP}) info symbol 0x400225 | |
12550 | _start + 5 in section .text of /tmp/a.out | |
12551 | (@value{GDBP}) info symbol 0x2aaaac2811cf | |
12552 | __read_nocancel + 6 in section .text of /usr/lib64/libc.so.6 | |
12553 | @end smallexample | |
12554 | ||
c906108c | 12555 | @kindex whatis |
62f3a2ba FF |
12556 | @item whatis [@var{arg}] |
12557 | Print the data type of @var{arg}, which can be either an expression or | |
12558 | a data type. With no argument, print the data type of @code{$}, the | |
12559 | last value in the value history. If @var{arg} is an expression, it is | |
12560 | not actually evaluated, and any side-effecting operations (such as | |
12561 | assignments or function calls) inside it do not take place. If | |
12562 | @var{arg} is a type name, it may be the name of a type or typedef, or | |
12563 | for C code it may have the form @samp{class @var{class-name}}, | |
12564 | @samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or | |
12565 | @samp{enum @var{enum-tag}}. | |
c906108c SS |
12566 | @xref{Expressions, ,Expressions}. |
12567 | ||
c906108c | 12568 | @kindex ptype |
62f3a2ba FF |
12569 | @item ptype [@var{arg}] |
12570 | @code{ptype} accepts the same arguments as @code{whatis}, but prints a | |
12571 | detailed description of the type, instead of just the name of the type. | |
12572 | @xref{Expressions, ,Expressions}. | |
c906108c SS |
12573 | |
12574 | For example, for this variable declaration: | |
12575 | ||
474c8240 | 12576 | @smallexample |
c906108c | 12577 | struct complex @{double real; double imag;@} v; |
474c8240 | 12578 | @end smallexample |
c906108c SS |
12579 | |
12580 | @noindent | |
12581 | the two commands give this output: | |
12582 | ||
474c8240 | 12583 | @smallexample |
c906108c SS |
12584 | @group |
12585 | (@value{GDBP}) whatis v | |
12586 | type = struct complex | |
12587 | (@value{GDBP}) ptype v | |
12588 | type = struct complex @{ | |
12589 | double real; | |
12590 | double imag; | |
12591 | @} | |
12592 | @end group | |
474c8240 | 12593 | @end smallexample |
c906108c SS |
12594 | |
12595 | @noindent | |
12596 | As with @code{whatis}, using @code{ptype} without an argument refers to | |
12597 | the type of @code{$}, the last value in the value history. | |
12598 | ||
ab1adacd EZ |
12599 | @cindex incomplete type |
12600 | Sometimes, programs use opaque data types or incomplete specifications | |
12601 | of complex data structure. If the debug information included in the | |
12602 | program does not allow @value{GDBN} to display a full declaration of | |
12603 | the data type, it will say @samp{<incomplete type>}. For example, | |
12604 | given these declarations: | |
12605 | ||
12606 | @smallexample | |
12607 | struct foo; | |
12608 | struct foo *fooptr; | |
12609 | @end smallexample | |
12610 | ||
12611 | @noindent | |
12612 | but no definition for @code{struct foo} itself, @value{GDBN} will say: | |
12613 | ||
12614 | @smallexample | |
ddb50cd7 | 12615 | (@value{GDBP}) ptype foo |
ab1adacd EZ |
12616 | $1 = <incomplete type> |
12617 | @end smallexample | |
12618 | ||
12619 | @noindent | |
12620 | ``Incomplete type'' is C terminology for data types that are not | |
12621 | completely specified. | |
12622 | ||
c906108c SS |
12623 | @kindex info types |
12624 | @item info types @var{regexp} | |
12625 | @itemx info types | |
09d4efe1 EZ |
12626 | Print a brief description of all types whose names match the regular |
12627 | expression @var{regexp} (or all types in your program, if you supply | |
12628 | no argument). Each complete typename is matched as though it were a | |
12629 | complete line; thus, @samp{i type value} gives information on all | |
12630 | types in your program whose names include the string @code{value}, but | |
12631 | @samp{i type ^value$} gives information only on types whose complete | |
12632 | name is @code{value}. | |
c906108c SS |
12633 | |
12634 | This command differs from @code{ptype} in two ways: first, like | |
12635 | @code{whatis}, it does not print a detailed description; second, it | |
12636 | lists all source files where a type is defined. | |
12637 | ||
b37052ae EZ |
12638 | @kindex info scope |
12639 | @cindex local variables | |
09d4efe1 | 12640 | @item info scope @var{location} |
b37052ae | 12641 | List all the variables local to a particular scope. This command |
09d4efe1 EZ |
12642 | accepts a @var{location} argument---a function name, a source line, or |
12643 | an address preceded by a @samp{*}, and prints all the variables local | |
2a25a5ba EZ |
12644 | to the scope defined by that location. (@xref{Specify Location}, for |
12645 | details about supported forms of @var{location}.) For example: | |
b37052ae EZ |
12646 | |
12647 | @smallexample | |
12648 | (@value{GDBP}) @b{info scope command_line_handler} | |
12649 | Scope for command_line_handler: | |
12650 | Symbol rl is an argument at stack/frame offset 8, length 4. | |
12651 | Symbol linebuffer is in static storage at address 0x150a18, length 4. | |
12652 | Symbol linelength is in static storage at address 0x150a1c, length 4. | |
12653 | Symbol p is a local variable in register $esi, length 4. | |
12654 | Symbol p1 is a local variable in register $ebx, length 4. | |
12655 | Symbol nline is a local variable in register $edx, length 4. | |
12656 | Symbol repeat is a local variable at frame offset -8, length 4. | |
12657 | @end smallexample | |
12658 | ||
f5c37c66 EZ |
12659 | @noindent |
12660 | This command is especially useful for determining what data to collect | |
12661 | during a @dfn{trace experiment}, see @ref{Tracepoint Actions, | |
12662 | collect}. | |
12663 | ||
c906108c SS |
12664 | @kindex info source |
12665 | @item info source | |
919d772c JB |
12666 | Show information about the current source file---that is, the source file for |
12667 | the function containing the current point of execution: | |
12668 | @itemize @bullet | |
12669 | @item | |
12670 | the name of the source file, and the directory containing it, | |
12671 | @item | |
12672 | the directory it was compiled in, | |
12673 | @item | |
12674 | its length, in lines, | |
12675 | @item | |
12676 | which programming language it is written in, | |
12677 | @item | |
12678 | whether the executable includes debugging information for that file, and | |
12679 | if so, what format the information is in (e.g., STABS, Dwarf 2, etc.), and | |
12680 | @item | |
12681 | whether the debugging information includes information about | |
12682 | preprocessor macros. | |
12683 | @end itemize | |
12684 | ||
c906108c SS |
12685 | |
12686 | @kindex info sources | |
12687 | @item info sources | |
12688 | Print the names of all source files in your program for which there is | |
12689 | debugging information, organized into two lists: files whose symbols | |
12690 | have already been read, and files whose symbols will be read when needed. | |
12691 | ||
12692 | @kindex info functions | |
12693 | @item info functions | |
12694 | Print the names and data types of all defined functions. | |
12695 | ||
12696 | @item info functions @var{regexp} | |
12697 | Print the names and data types of all defined functions | |
12698 | whose names contain a match for regular expression @var{regexp}. | |
12699 | Thus, @samp{info fun step} finds all functions whose names | |
12700 | include @code{step}; @samp{info fun ^step} finds those whose names | |
b383017d | 12701 | start with @code{step}. If a function name contains characters |
c1468174 | 12702 | that conflict with the regular expression language (e.g.@: |
1c5dfdad | 12703 | @samp{operator*()}), they may be quoted with a backslash. |
c906108c SS |
12704 | |
12705 | @kindex info variables | |
12706 | @item info variables | |
12707 | Print the names and data types of all variables that are declared | |
6ca652b0 | 12708 | outside of functions (i.e.@: excluding local variables). |
c906108c SS |
12709 | |
12710 | @item info variables @var{regexp} | |
12711 | Print the names and data types of all variables (except for local | |
12712 | variables) whose names contain a match for regular expression | |
12713 | @var{regexp}. | |
12714 | ||
b37303ee | 12715 | @kindex info classes |
721c2651 | 12716 | @cindex Objective-C, classes and selectors |
b37303ee AF |
12717 | @item info classes |
12718 | @itemx info classes @var{regexp} | |
12719 | Display all Objective-C classes in your program, or | |
12720 | (with the @var{regexp} argument) all those matching a particular regular | |
12721 | expression. | |
12722 | ||
12723 | @kindex info selectors | |
12724 | @item info selectors | |
12725 | @itemx info selectors @var{regexp} | |
12726 | Display all Objective-C selectors in your program, or | |
12727 | (with the @var{regexp} argument) all those matching a particular regular | |
12728 | expression. | |
12729 | ||
c906108c SS |
12730 | @ignore |
12731 | This was never implemented. | |
12732 | @kindex info methods | |
12733 | @item info methods | |
12734 | @itemx info methods @var{regexp} | |
12735 | The @code{info methods} command permits the user to examine all defined | |
b37052ae EZ |
12736 | methods within C@t{++} program, or (with the @var{regexp} argument) a |
12737 | specific set of methods found in the various C@t{++} classes. Many | |
12738 | C@t{++} classes provide a large number of methods. Thus, the output | |
c906108c SS |
12739 | from the @code{ptype} command can be overwhelming and hard to use. The |
12740 | @code{info-methods} command filters the methods, printing only those | |
12741 | which match the regular-expression @var{regexp}. | |
12742 | @end ignore | |
12743 | ||
c906108c SS |
12744 | @cindex reloading symbols |
12745 | Some systems allow individual object files that make up your program to | |
7a292a7a SS |
12746 | be replaced without stopping and restarting your program. For example, |
12747 | in VxWorks you can simply recompile a defective object file and keep on | |
12748 | running. If you are running on one of these systems, you can allow | |
12749 | @value{GDBN} to reload the symbols for automatically relinked modules: | |
c906108c SS |
12750 | |
12751 | @table @code | |
12752 | @kindex set symbol-reloading | |
12753 | @item set symbol-reloading on | |
12754 | Replace symbol definitions for the corresponding source file when an | |
12755 | object file with a particular name is seen again. | |
12756 | ||
12757 | @item set symbol-reloading off | |
6d2ebf8b SS |
12758 | Do not replace symbol definitions when encountering object files of the |
12759 | same name more than once. This is the default state; if you are not | |
12760 | running on a system that permits automatic relinking of modules, you | |
12761 | should leave @code{symbol-reloading} off, since otherwise @value{GDBN} | |
12762 | may discard symbols when linking large programs, that may contain | |
12763 | several modules (from different directories or libraries) with the same | |
12764 | name. | |
c906108c SS |
12765 | |
12766 | @kindex show symbol-reloading | |
12767 | @item show symbol-reloading | |
12768 | Show the current @code{on} or @code{off} setting. | |
12769 | @end table | |
c906108c | 12770 | |
9c16f35a | 12771 | @cindex opaque data types |
c906108c SS |
12772 | @kindex set opaque-type-resolution |
12773 | @item set opaque-type-resolution on | |
12774 | Tell @value{GDBN} to resolve opaque types. An opaque type is a type | |
12775 | declared as a pointer to a @code{struct}, @code{class}, or | |
12776 | @code{union}---for example, @code{struct MyType *}---that is used in one | |
12777 | source file although the full declaration of @code{struct MyType} is in | |
12778 | another source file. The default is on. | |
12779 | ||
12780 | A change in the setting of this subcommand will not take effect until | |
12781 | the next time symbols for a file are loaded. | |
12782 | ||
12783 | @item set opaque-type-resolution off | |
12784 | Tell @value{GDBN} not to resolve opaque types. In this case, the type | |
12785 | is printed as follows: | |
12786 | @smallexample | |
12787 | @{<no data fields>@} | |
12788 | @end smallexample | |
12789 | ||
12790 | @kindex show opaque-type-resolution | |
12791 | @item show opaque-type-resolution | |
12792 | Show whether opaque types are resolved or not. | |
c906108c SS |
12793 | |
12794 | @kindex maint print symbols | |
12795 | @cindex symbol dump | |
12796 | @kindex maint print psymbols | |
12797 | @cindex partial symbol dump | |
12798 | @item maint print symbols @var{filename} | |
12799 | @itemx maint print psymbols @var{filename} | |
12800 | @itemx maint print msymbols @var{filename} | |
12801 | Write a dump of debugging symbol data into the file @var{filename}. | |
12802 | These commands are used to debug the @value{GDBN} symbol-reading code. Only | |
12803 | symbols with debugging data are included. If you use @samp{maint print | |
12804 | symbols}, @value{GDBN} includes all the symbols for which it has already | |
12805 | collected full details: that is, @var{filename} reflects symbols for | |
12806 | only those files whose symbols @value{GDBN} has read. You can use the | |
12807 | command @code{info sources} to find out which files these are. If you | |
12808 | use @samp{maint print psymbols} instead, the dump shows information about | |
12809 | symbols that @value{GDBN} only knows partially---that is, symbols defined in | |
12810 | files that @value{GDBN} has skimmed, but not yet read completely. Finally, | |
12811 | @samp{maint print msymbols} dumps just the minimal symbol information | |
12812 | required for each object file from which @value{GDBN} has read some symbols. | |
79a6e687 | 12813 | @xref{Files, ,Commands to Specify Files}, for a discussion of how |
c906108c | 12814 | @value{GDBN} reads symbols (in the description of @code{symbol-file}). |
44ea7b70 | 12815 | |
5e7b2f39 JB |
12816 | @kindex maint info symtabs |
12817 | @kindex maint info psymtabs | |
44ea7b70 JB |
12818 | @cindex listing @value{GDBN}'s internal symbol tables |
12819 | @cindex symbol tables, listing @value{GDBN}'s internal | |
12820 | @cindex full symbol tables, listing @value{GDBN}'s internal | |
12821 | @cindex partial symbol tables, listing @value{GDBN}'s internal | |
5e7b2f39 JB |
12822 | @item maint info symtabs @r{[} @var{regexp} @r{]} |
12823 | @itemx maint info psymtabs @r{[} @var{regexp} @r{]} | |
44ea7b70 JB |
12824 | |
12825 | List the @code{struct symtab} or @code{struct partial_symtab} | |
12826 | structures whose names match @var{regexp}. If @var{regexp} is not | |
12827 | given, list them all. The output includes expressions which you can | |
12828 | copy into a @value{GDBN} debugging this one to examine a particular | |
12829 | structure in more detail. For example: | |
12830 | ||
12831 | @smallexample | |
5e7b2f39 | 12832 | (@value{GDBP}) maint info psymtabs dwarf2read |
44ea7b70 JB |
12833 | @{ objfile /home/gnu/build/gdb/gdb |
12834 | ((struct objfile *) 0x82e69d0) | |
b383017d | 12835 | @{ psymtab /home/gnu/src/gdb/dwarf2read.c |
44ea7b70 JB |
12836 | ((struct partial_symtab *) 0x8474b10) |
12837 | readin no | |
12838 | fullname (null) | |
12839 | text addresses 0x814d3c8 -- 0x8158074 | |
12840 | globals (* (struct partial_symbol **) 0x8507a08 @@ 9) | |
12841 | statics (* (struct partial_symbol **) 0x40e95b78 @@ 2882) | |
12842 | dependencies (none) | |
12843 | @} | |
12844 | @} | |
5e7b2f39 | 12845 | (@value{GDBP}) maint info symtabs |
44ea7b70 JB |
12846 | (@value{GDBP}) |
12847 | @end smallexample | |
12848 | @noindent | |
12849 | We see that there is one partial symbol table whose filename contains | |
12850 | the string @samp{dwarf2read}, belonging to the @samp{gdb} executable; | |
12851 | and we see that @value{GDBN} has not read in any symtabs yet at all. | |
12852 | If we set a breakpoint on a function, that will cause @value{GDBN} to | |
12853 | read the symtab for the compilation unit containing that function: | |
12854 | ||
12855 | @smallexample | |
12856 | (@value{GDBP}) break dwarf2_psymtab_to_symtab | |
12857 | Breakpoint 1 at 0x814e5da: file /home/gnu/src/gdb/dwarf2read.c, | |
12858 | line 1574. | |
5e7b2f39 | 12859 | (@value{GDBP}) maint info symtabs |
b383017d | 12860 | @{ objfile /home/gnu/build/gdb/gdb |
44ea7b70 | 12861 | ((struct objfile *) 0x82e69d0) |
b383017d | 12862 | @{ symtab /home/gnu/src/gdb/dwarf2read.c |
44ea7b70 JB |
12863 | ((struct symtab *) 0x86c1f38) |
12864 | dirname (null) | |
12865 | fullname (null) | |
12866 | blockvector ((struct blockvector *) 0x86c1bd0) (primary) | |
1b39d5c0 | 12867 | linetable ((struct linetable *) 0x8370fa0) |
44ea7b70 JB |
12868 | debugformat DWARF 2 |
12869 | @} | |
12870 | @} | |
b383017d | 12871 | (@value{GDBP}) |
44ea7b70 | 12872 | @end smallexample |
c906108c SS |
12873 | @end table |
12874 | ||
44ea7b70 | 12875 | |
6d2ebf8b | 12876 | @node Altering |
c906108c SS |
12877 | @chapter Altering Execution |
12878 | ||
12879 | Once you think you have found an error in your program, you might want to | |
12880 | find out for certain whether correcting the apparent error would lead to | |
12881 | correct results in the rest of the run. You can find the answer by | |
12882 | experiment, using the @value{GDBN} features for altering execution of the | |
12883 | program. | |
12884 | ||
12885 | For example, you can store new values into variables or memory | |
7a292a7a SS |
12886 | locations, give your program a signal, restart it at a different |
12887 | address, or even return prematurely from a function. | |
c906108c SS |
12888 | |
12889 | @menu | |
12890 | * Assignment:: Assignment to variables | |
12891 | * Jumping:: Continuing at a different address | |
c906108c | 12892 | * Signaling:: Giving your program a signal |
c906108c SS |
12893 | * Returning:: Returning from a function |
12894 | * Calling:: Calling your program's functions | |
12895 | * Patching:: Patching your program | |
12896 | @end menu | |
12897 | ||
6d2ebf8b | 12898 | @node Assignment |
79a6e687 | 12899 | @section Assignment to Variables |
c906108c SS |
12900 | |
12901 | @cindex assignment | |
12902 | @cindex setting variables | |
12903 | To alter the value of a variable, evaluate an assignment expression. | |
12904 | @xref{Expressions, ,Expressions}. For example, | |
12905 | ||
474c8240 | 12906 | @smallexample |
c906108c | 12907 | print x=4 |
474c8240 | 12908 | @end smallexample |
c906108c SS |
12909 | |
12910 | @noindent | |
12911 | stores the value 4 into the variable @code{x}, and then prints the | |
5d161b24 | 12912 | value of the assignment expression (which is 4). |
c906108c SS |
12913 | @xref{Languages, ,Using @value{GDBN} with Different Languages}, for more |
12914 | information on operators in supported languages. | |
c906108c SS |
12915 | |
12916 | @kindex set variable | |
12917 | @cindex variables, setting | |
12918 | If you are not interested in seeing the value of the assignment, use the | |
12919 | @code{set} command instead of the @code{print} command. @code{set} is | |
12920 | really the same as @code{print} except that the expression's value is | |
12921 | not printed and is not put in the value history (@pxref{Value History, | |
79a6e687 | 12922 | ,Value History}). The expression is evaluated only for its effects. |
c906108c | 12923 | |
c906108c SS |
12924 | If the beginning of the argument string of the @code{set} command |
12925 | appears identical to a @code{set} subcommand, use the @code{set | |
12926 | variable} command instead of just @code{set}. This command is identical | |
12927 | to @code{set} except for its lack of subcommands. For example, if your | |
12928 | program has a variable @code{width}, you get an error if you try to set | |
12929 | a new value with just @samp{set width=13}, because @value{GDBN} has the | |
12930 | command @code{set width}: | |
12931 | ||
474c8240 | 12932 | @smallexample |
c906108c SS |
12933 | (@value{GDBP}) whatis width |
12934 | type = double | |
12935 | (@value{GDBP}) p width | |
12936 | $4 = 13 | |
12937 | (@value{GDBP}) set width=47 | |
12938 | Invalid syntax in expression. | |
474c8240 | 12939 | @end smallexample |
c906108c SS |
12940 | |
12941 | @noindent | |
12942 | The invalid expression, of course, is @samp{=47}. In | |
12943 | order to actually set the program's variable @code{width}, use | |
12944 | ||
474c8240 | 12945 | @smallexample |
c906108c | 12946 | (@value{GDBP}) set var width=47 |
474c8240 | 12947 | @end smallexample |
53a5351d | 12948 | |
c906108c SS |
12949 | Because the @code{set} command has many subcommands that can conflict |
12950 | with the names of program variables, it is a good idea to use the | |
12951 | @code{set variable} command instead of just @code{set}. For example, if | |
12952 | your program has a variable @code{g}, you run into problems if you try | |
12953 | to set a new value with just @samp{set g=4}, because @value{GDBN} has | |
12954 | the command @code{set gnutarget}, abbreviated @code{set g}: | |
12955 | ||
474c8240 | 12956 | @smallexample |
c906108c SS |
12957 | @group |
12958 | (@value{GDBP}) whatis g | |
12959 | type = double | |
12960 | (@value{GDBP}) p g | |
12961 | $1 = 1 | |
12962 | (@value{GDBP}) set g=4 | |
2df3850c | 12963 | (@value{GDBP}) p g |
c906108c SS |
12964 | $2 = 1 |
12965 | (@value{GDBP}) r | |
12966 | The program being debugged has been started already. | |
12967 | Start it from the beginning? (y or n) y | |
12968 | Starting program: /home/smith/cc_progs/a.out | |
6d2ebf8b SS |
12969 | "/home/smith/cc_progs/a.out": can't open to read symbols: |
12970 | Invalid bfd target. | |
c906108c SS |
12971 | (@value{GDBP}) show g |
12972 | The current BFD target is "=4". | |
12973 | @end group | |
474c8240 | 12974 | @end smallexample |
c906108c SS |
12975 | |
12976 | @noindent | |
12977 | The program variable @code{g} did not change, and you silently set the | |
12978 | @code{gnutarget} to an invalid value. In order to set the variable | |
12979 | @code{g}, use | |
12980 | ||
474c8240 | 12981 | @smallexample |
c906108c | 12982 | (@value{GDBP}) set var g=4 |
474c8240 | 12983 | @end smallexample |
c906108c SS |
12984 | |
12985 | @value{GDBN} allows more implicit conversions in assignments than C; you can | |
12986 | freely store an integer value into a pointer variable or vice versa, | |
12987 | and you can convert any structure to any other structure that is the | |
12988 | same length or shorter. | |
12989 | @comment FIXME: how do structs align/pad in these conversions? | |
12990 | @comment /doc@cygnus.com 18dec1990 | |
12991 | ||
12992 | To store values into arbitrary places in memory, use the @samp{@{@dots{}@}} | |
12993 | construct to generate a value of specified type at a specified address | |
12994 | (@pxref{Expressions, ,Expressions}). For example, @code{@{int@}0x83040} refers | |
12995 | to memory location @code{0x83040} as an integer (which implies a certain size | |
12996 | and representation in memory), and | |
12997 | ||
474c8240 | 12998 | @smallexample |
c906108c | 12999 | set @{int@}0x83040 = 4 |
474c8240 | 13000 | @end smallexample |
c906108c SS |
13001 | |
13002 | @noindent | |
13003 | stores the value 4 into that memory location. | |
13004 | ||
6d2ebf8b | 13005 | @node Jumping |
79a6e687 | 13006 | @section Continuing at a Different Address |
c906108c SS |
13007 | |
13008 | Ordinarily, when you continue your program, you do so at the place where | |
13009 | it stopped, with the @code{continue} command. You can instead continue at | |
13010 | an address of your own choosing, with the following commands: | |
13011 | ||
13012 | @table @code | |
13013 | @kindex jump | |
13014 | @item jump @var{linespec} | |
2a25a5ba EZ |
13015 | @itemx jump @var{location} |
13016 | Resume execution at line @var{linespec} or at address given by | |
13017 | @var{location}. Execution stops again immediately if there is a | |
13018 | breakpoint there. @xref{Specify Location}, for a description of the | |
13019 | different forms of @var{linespec} and @var{location}. It is common | |
13020 | practice to use the @code{tbreak} command in conjunction with | |
13021 | @code{jump}. @xref{Set Breaks, ,Setting Breakpoints}. | |
c906108c SS |
13022 | |
13023 | The @code{jump} command does not change the current stack frame, or | |
13024 | the stack pointer, or the contents of any memory location or any | |
13025 | register other than the program counter. If line @var{linespec} is in | |
13026 | a different function from the one currently executing, the results may | |
13027 | be bizarre if the two functions expect different patterns of arguments or | |
13028 | of local variables. For this reason, the @code{jump} command requests | |
13029 | confirmation if the specified line is not in the function currently | |
13030 | executing. However, even bizarre results are predictable if you are | |
13031 | well acquainted with the machine-language code of your program. | |
c906108c SS |
13032 | @end table |
13033 | ||
c906108c | 13034 | @c Doesn't work on HP-UX; have to set $pcoqh and $pcoqt. |
53a5351d JM |
13035 | On many systems, you can get much the same effect as the @code{jump} |
13036 | command by storing a new value into the register @code{$pc}. The | |
13037 | difference is that this does not start your program running; it only | |
13038 | changes the address of where it @emph{will} run when you continue. For | |
13039 | example, | |
c906108c | 13040 | |
474c8240 | 13041 | @smallexample |
c906108c | 13042 | set $pc = 0x485 |
474c8240 | 13043 | @end smallexample |
c906108c SS |
13044 | |
13045 | @noindent | |
13046 | makes the next @code{continue} command or stepping command execute at | |
13047 | address @code{0x485}, rather than at the address where your program stopped. | |
79a6e687 | 13048 | @xref{Continuing and Stepping, ,Continuing and Stepping}. |
c906108c SS |
13049 | |
13050 | The most common occasion to use the @code{jump} command is to back | |
13051 | up---perhaps with more breakpoints set---over a portion of a program | |
13052 | that has already executed, in order to examine its execution in more | |
13053 | detail. | |
13054 | ||
c906108c | 13055 | @c @group |
6d2ebf8b | 13056 | @node Signaling |
79a6e687 | 13057 | @section Giving your Program a Signal |
9c16f35a | 13058 | @cindex deliver a signal to a program |
c906108c SS |
13059 | |
13060 | @table @code | |
13061 | @kindex signal | |
13062 | @item signal @var{signal} | |
13063 | Resume execution where your program stopped, but immediately give it the | |
13064 | signal @var{signal}. @var{signal} can be the name or the number of a | |
13065 | signal. For example, on many systems @code{signal 2} and @code{signal | |
13066 | SIGINT} are both ways of sending an interrupt signal. | |
13067 | ||
13068 | Alternatively, if @var{signal} is zero, continue execution without | |
13069 | giving a signal. This is useful when your program stopped on account of | |
13070 | a signal and would ordinary see the signal when resumed with the | |
13071 | @code{continue} command; @samp{signal 0} causes it to resume without a | |
13072 | signal. | |
13073 | ||
13074 | @code{signal} does not repeat when you press @key{RET} a second time | |
13075 | after executing the command. | |
13076 | @end table | |
13077 | @c @end group | |
13078 | ||
13079 | Invoking the @code{signal} command is not the same as invoking the | |
13080 | @code{kill} utility from the shell. Sending a signal with @code{kill} | |
13081 | causes @value{GDBN} to decide what to do with the signal depending on | |
13082 | the signal handling tables (@pxref{Signals}). The @code{signal} command | |
13083 | passes the signal directly to your program. | |
13084 | ||
c906108c | 13085 | |
6d2ebf8b | 13086 | @node Returning |
79a6e687 | 13087 | @section Returning from a Function |
c906108c SS |
13088 | |
13089 | @table @code | |
13090 | @cindex returning from a function | |
13091 | @kindex return | |
13092 | @item return | |
13093 | @itemx return @var{expression} | |
13094 | You can cancel execution of a function call with the @code{return} | |
13095 | command. If you give an | |
13096 | @var{expression} argument, its value is used as the function's return | |
13097 | value. | |
13098 | @end table | |
13099 | ||
13100 | When you use @code{return}, @value{GDBN} discards the selected stack frame | |
13101 | (and all frames within it). You can think of this as making the | |
13102 | discarded frame return prematurely. If you wish to specify a value to | |
13103 | be returned, give that value as the argument to @code{return}. | |
13104 | ||
13105 | This pops the selected stack frame (@pxref{Selection, ,Selecting a | |
79a6e687 | 13106 | Frame}), and any other frames inside of it, leaving its caller as the |
c906108c SS |
13107 | innermost remaining frame. That frame becomes selected. The |
13108 | specified value is stored in the registers used for returning values | |
13109 | of functions. | |
13110 | ||
13111 | The @code{return} command does not resume execution; it leaves the | |
13112 | program stopped in the state that would exist if the function had just | |
13113 | returned. In contrast, the @code{finish} command (@pxref{Continuing | |
79a6e687 | 13114 | and Stepping, ,Continuing and Stepping}) resumes execution until the |
c906108c SS |
13115 | selected stack frame returns naturally. |
13116 | ||
61ff14c6 JK |
13117 | @value{GDBN} needs to know how the @var{expression} argument should be set for |
13118 | the inferior. The concrete registers assignment depends on the OS ABI and the | |
13119 | type being returned by the selected stack frame. For example it is common for | |
13120 | OS ABI to return floating point values in FPU registers while integer values in | |
13121 | CPU registers. Still some ABIs return even floating point values in CPU | |
13122 | registers. Larger integer widths (such as @code{long long int}) also have | |
13123 | specific placement rules. @value{GDBN} already knows the OS ABI from its | |
13124 | current target so it needs to find out also the type being returned to make the | |
13125 | assignment into the right register(s). | |
13126 | ||
13127 | Normally, the selected stack frame has debug info. @value{GDBN} will always | |
13128 | use the debug info instead of the implicit type of @var{expression} when the | |
13129 | debug info is available. For example, if you type @kbd{return -1}, and the | |
13130 | function in the current stack frame is declared to return a @code{long long | |
13131 | int}, @value{GDBN} transparently converts the implicit @code{int} value of -1 | |
13132 | into a @code{long long int}: | |
13133 | ||
13134 | @smallexample | |
13135 | Breakpoint 1, func () at gdb.base/return-nodebug.c:29 | |
13136 | 29 return 31; | |
13137 | (@value{GDBP}) return -1 | |
13138 | Make func return now? (y or n) y | |
13139 | #0 0x004004f6 in main () at gdb.base/return-nodebug.c:43 | |
13140 | 43 printf ("result=%lld\n", func ()); | |
13141 | (@value{GDBP}) | |
13142 | @end smallexample | |
13143 | ||
13144 | However, if the selected stack frame does not have a debug info, e.g., if the | |
13145 | function was compiled without debug info, @value{GDBN} has to find out the type | |
13146 | to return from user. Specifying a different type by mistake may set the value | |
13147 | in different inferior registers than the caller code expects. For example, | |
13148 | typing @kbd{return -1} with its implicit type @code{int} would set only a part | |
13149 | of a @code{long long int} result for a debug info less function (on 32-bit | |
13150 | architectures). Therefore the user is required to specify the return type by | |
13151 | an appropriate cast explicitly: | |
13152 | ||
13153 | @smallexample | |
13154 | Breakpoint 2, 0x0040050b in func () | |
13155 | (@value{GDBP}) return -1 | |
13156 | Return value type not available for selected stack frame. | |
13157 | Please use an explicit cast of the value to return. | |
13158 | (@value{GDBP}) return (long long int) -1 | |
13159 | Make selected stack frame return now? (y or n) y | |
13160 | #0 0x00400526 in main () | |
13161 | (@value{GDBP}) | |
13162 | @end smallexample | |
13163 | ||
6d2ebf8b | 13164 | @node Calling |
79a6e687 | 13165 | @section Calling Program Functions |
c906108c | 13166 | |
f8568604 | 13167 | @table @code |
c906108c | 13168 | @cindex calling functions |
f8568604 EZ |
13169 | @cindex inferior functions, calling |
13170 | @item print @var{expr} | |
d3e8051b | 13171 | Evaluate the expression @var{expr} and display the resulting value. |
f8568604 EZ |
13172 | @var{expr} may include calls to functions in the program being |
13173 | debugged. | |
13174 | ||
c906108c | 13175 | @kindex call |
c906108c SS |
13176 | @item call @var{expr} |
13177 | Evaluate the expression @var{expr} without displaying @code{void} | |
13178 | returned values. | |
c906108c SS |
13179 | |
13180 | You can use this variant of the @code{print} command if you want to | |
f8568604 EZ |
13181 | execute a function from your program that does not return anything |
13182 | (a.k.a.@: @dfn{a void function}), but without cluttering the output | |
13183 | with @code{void} returned values that @value{GDBN} will otherwise | |
13184 | print. If the result is not void, it is printed and saved in the | |
13185 | value history. | |
13186 | @end table | |
13187 | ||
9c16f35a EZ |
13188 | It is possible for the function you call via the @code{print} or |
13189 | @code{call} command to generate a signal (e.g., if there's a bug in | |
13190 | the function, or if you passed it incorrect arguments). What happens | |
13191 | in that case is controlled by the @code{set unwindonsignal} command. | |
13192 | ||
7cd1089b PM |
13193 | Similarly, with a C@t{++} program it is possible for the function you |
13194 | call via the @code{print} or @code{call} command to generate an | |
13195 | exception that is not handled due to the constraints of the dummy | |
13196 | frame. In this case, any exception that is raised in the frame, but has | |
13197 | an out-of-frame exception handler will not be found. GDB builds a | |
13198 | dummy-frame for the inferior function call, and the unwinder cannot | |
13199 | seek for exception handlers outside of this dummy-frame. What happens | |
13200 | in that case is controlled by the | |
13201 | @code{set unwind-on-terminating-exception} command. | |
13202 | ||
9c16f35a EZ |
13203 | @table @code |
13204 | @item set unwindonsignal | |
13205 | @kindex set unwindonsignal | |
13206 | @cindex unwind stack in called functions | |
13207 | @cindex call dummy stack unwinding | |
13208 | Set unwinding of the stack if a signal is received while in a function | |
13209 | that @value{GDBN} called in the program being debugged. If set to on, | |
13210 | @value{GDBN} unwinds the stack it created for the call and restores | |
13211 | the context to what it was before the call. If set to off (the | |
13212 | default), @value{GDBN} stops in the frame where the signal was | |
13213 | received. | |
13214 | ||
13215 | @item show unwindonsignal | |
13216 | @kindex show unwindonsignal | |
13217 | Show the current setting of stack unwinding in the functions called by | |
13218 | @value{GDBN}. | |
7cd1089b PM |
13219 | |
13220 | @item set unwind-on-terminating-exception | |
13221 | @kindex set unwind-on-terminating-exception | |
13222 | @cindex unwind stack in called functions with unhandled exceptions | |
13223 | @cindex call dummy stack unwinding on unhandled exception. | |
13224 | Set unwinding of the stack if a C@t{++} exception is raised, but left | |
13225 | unhandled while in a function that @value{GDBN} called in the program being | |
13226 | debugged. If set to on (the default), @value{GDBN} unwinds the stack | |
13227 | it created for the call and restores the context to what it was before | |
13228 | the call. If set to off, @value{GDBN} the exception is delivered to | |
13229 | the default C@t{++} exception handler and the inferior terminated. | |
13230 | ||
13231 | @item show unwind-on-terminating-exception | |
13232 | @kindex show unwind-on-terminating-exception | |
13233 | Show the current setting of stack unwinding in the functions called by | |
13234 | @value{GDBN}. | |
13235 | ||
9c16f35a EZ |
13236 | @end table |
13237 | ||
f8568604 EZ |
13238 | @cindex weak alias functions |
13239 | Sometimes, a function you wish to call is actually a @dfn{weak alias} | |
13240 | for another function. In such case, @value{GDBN} might not pick up | |
13241 | the type information, including the types of the function arguments, | |
13242 | which causes @value{GDBN} to call the inferior function incorrectly. | |
13243 | As a result, the called function will function erroneously and may | |
13244 | even crash. A solution to that is to use the name of the aliased | |
13245 | function instead. | |
c906108c | 13246 | |
6d2ebf8b | 13247 | @node Patching |
79a6e687 | 13248 | @section Patching Programs |
7a292a7a | 13249 | |
c906108c SS |
13250 | @cindex patching binaries |
13251 | @cindex writing into executables | |
c906108c | 13252 | @cindex writing into corefiles |
c906108c | 13253 | |
7a292a7a SS |
13254 | By default, @value{GDBN} opens the file containing your program's |
13255 | executable code (or the corefile) read-only. This prevents accidental | |
13256 | alterations to machine code; but it also prevents you from intentionally | |
13257 | patching your program's binary. | |
c906108c SS |
13258 | |
13259 | If you'd like to be able to patch the binary, you can specify that | |
13260 | explicitly with the @code{set write} command. For example, you might | |
13261 | want to turn on internal debugging flags, or even to make emergency | |
13262 | repairs. | |
13263 | ||
13264 | @table @code | |
13265 | @kindex set write | |
13266 | @item set write on | |
13267 | @itemx set write off | |
7a292a7a | 13268 | If you specify @samp{set write on}, @value{GDBN} opens executable and |
20924a55 | 13269 | core files for both reading and writing; if you specify @kbd{set write |
c906108c SS |
13270 | off} (the default), @value{GDBN} opens them read-only. |
13271 | ||
13272 | If you have already loaded a file, you must load it again (using the | |
7a292a7a SS |
13273 | @code{exec-file} or @code{core-file} command) after changing @code{set |
13274 | write}, for your new setting to take effect. | |
c906108c SS |
13275 | |
13276 | @item show write | |
13277 | @kindex show write | |
7a292a7a SS |
13278 | Display whether executable files and core files are opened for writing |
13279 | as well as reading. | |
c906108c SS |
13280 | @end table |
13281 | ||
6d2ebf8b | 13282 | @node GDB Files |
c906108c SS |
13283 | @chapter @value{GDBN} Files |
13284 | ||
7a292a7a SS |
13285 | @value{GDBN} needs to know the file name of the program to be debugged, |
13286 | both in order to read its symbol table and in order to start your | |
13287 | program. To debug a core dump of a previous run, you must also tell | |
13288 | @value{GDBN} the name of the core dump file. | |
c906108c SS |
13289 | |
13290 | @menu | |
13291 | * Files:: Commands to specify files | |
5b5d99cf | 13292 | * Separate Debug Files:: Debugging information in separate files |
c906108c | 13293 | * Symbol Errors:: Errors reading symbol files |
b14b1491 | 13294 | * Data Files:: GDB data files |
c906108c SS |
13295 | @end menu |
13296 | ||
6d2ebf8b | 13297 | @node Files |
79a6e687 | 13298 | @section Commands to Specify Files |
c906108c | 13299 | |
7a292a7a | 13300 | @cindex symbol table |
c906108c | 13301 | @cindex core dump file |
7a292a7a SS |
13302 | |
13303 | You may want to specify executable and core dump file names. The usual | |
13304 | way to do this is at start-up time, using the arguments to | |
13305 | @value{GDBN}'s start-up commands (@pxref{Invocation, , Getting In and | |
13306 | Out of @value{GDBN}}). | |
c906108c SS |
13307 | |
13308 | Occasionally it is necessary to change to a different file during a | |
397ca115 EZ |
13309 | @value{GDBN} session. Or you may run @value{GDBN} and forget to |
13310 | specify a file you want to use. Or you are debugging a remote target | |
79a6e687 BW |
13311 | via @code{gdbserver} (@pxref{Server, file, Using the @code{gdbserver} |
13312 | Program}). In these situations the @value{GDBN} commands to specify | |
0869d01b | 13313 | new files are useful. |
c906108c SS |
13314 | |
13315 | @table @code | |
13316 | @cindex executable file | |
13317 | @kindex file | |
13318 | @item file @var{filename} | |
13319 | Use @var{filename} as the program to be debugged. It is read for its | |
13320 | symbols and for the contents of pure memory. It is also the program | |
13321 | executed when you use the @code{run} command. If you do not specify a | |
5d161b24 DB |
13322 | directory and the file is not found in the @value{GDBN} working directory, |
13323 | @value{GDBN} uses the environment variable @code{PATH} as a list of | |
13324 | directories to search, just as the shell does when looking for a program | |
13325 | to run. You can change the value of this variable, for both @value{GDBN} | |
c906108c SS |
13326 | and your program, using the @code{path} command. |
13327 | ||
fc8be69e EZ |
13328 | @cindex unlinked object files |
13329 | @cindex patching object files | |
13330 | You can load unlinked object @file{.o} files into @value{GDBN} using | |
13331 | the @code{file} command. You will not be able to ``run'' an object | |
13332 | file, but you can disassemble functions and inspect variables. Also, | |
13333 | if the underlying BFD functionality supports it, you could use | |
13334 | @kbd{gdb -write} to patch object files using this technique. Note | |
13335 | that @value{GDBN} can neither interpret nor modify relocations in this | |
13336 | case, so branches and some initialized variables will appear to go to | |
13337 | the wrong place. But this feature is still handy from time to time. | |
13338 | ||
c906108c SS |
13339 | @item file |
13340 | @code{file} with no argument makes @value{GDBN} discard any information it | |
13341 | has on both executable file and the symbol table. | |
13342 | ||
13343 | @kindex exec-file | |
13344 | @item exec-file @r{[} @var{filename} @r{]} | |
13345 | Specify that the program to be run (but not the symbol table) is found | |
13346 | in @var{filename}. @value{GDBN} searches the environment variable @code{PATH} | |
13347 | if necessary to locate your program. Omitting @var{filename} means to | |
13348 | discard information on the executable file. | |
13349 | ||
13350 | @kindex symbol-file | |
13351 | @item symbol-file @r{[} @var{filename} @r{]} | |
13352 | Read symbol table information from file @var{filename}. @code{PATH} is | |
13353 | searched when necessary. Use the @code{file} command to get both symbol | |
13354 | table and program to run from the same file. | |
13355 | ||
13356 | @code{symbol-file} with no argument clears out @value{GDBN} information on your | |
13357 | program's symbol table. | |
13358 | ||
ae5a43e0 DJ |
13359 | The @code{symbol-file} command causes @value{GDBN} to forget the contents of |
13360 | some breakpoints and auto-display expressions. This is because they may | |
13361 | contain pointers to the internal data recording symbols and data types, | |
13362 | which are part of the old symbol table data being discarded inside | |
13363 | @value{GDBN}. | |
c906108c SS |
13364 | |
13365 | @code{symbol-file} does not repeat if you press @key{RET} again after | |
13366 | executing it once. | |
13367 | ||
13368 | When @value{GDBN} is configured for a particular environment, it | |
13369 | understands debugging information in whatever format is the standard | |
13370 | generated for that environment; you may use either a @sc{gnu} compiler, or | |
13371 | other compilers that adhere to the local conventions. | |
c906108c | 13372 | Best results are usually obtained from @sc{gnu} compilers; for example, |
e22ea452 | 13373 | using @code{@value{NGCC}} you can generate debugging information for |
c906108c | 13374 | optimized code. |
c906108c SS |
13375 | |
13376 | For most kinds of object files, with the exception of old SVR3 systems | |
13377 | using COFF, the @code{symbol-file} command does not normally read the | |
13378 | symbol table in full right away. Instead, it scans the symbol table | |
13379 | quickly to find which source files and which symbols are present. The | |
13380 | details are read later, one source file at a time, as they are needed. | |
13381 | ||
13382 | The purpose of this two-stage reading strategy is to make @value{GDBN} | |
13383 | start up faster. For the most part, it is invisible except for | |
13384 | occasional pauses while the symbol table details for a particular source | |
13385 | file are being read. (The @code{set verbose} command can turn these | |
13386 | pauses into messages if desired. @xref{Messages/Warnings, ,Optional | |
79a6e687 | 13387 | Warnings and Messages}.) |
c906108c | 13388 | |
c906108c SS |
13389 | We have not implemented the two-stage strategy for COFF yet. When the |
13390 | symbol table is stored in COFF format, @code{symbol-file} reads the | |
13391 | symbol table data in full right away. Note that ``stabs-in-COFF'' | |
13392 | still does the two-stage strategy, since the debug info is actually | |
13393 | in stabs format. | |
13394 | ||
13395 | @kindex readnow | |
13396 | @cindex reading symbols immediately | |
13397 | @cindex symbols, reading immediately | |
a94ab193 EZ |
13398 | @item symbol-file @var{filename} @r{[} -readnow @r{]} |
13399 | @itemx file @var{filename} @r{[} -readnow @r{]} | |
c906108c SS |
13400 | You can override the @value{GDBN} two-stage strategy for reading symbol |
13401 | tables by using the @samp{-readnow} option with any of the commands that | |
13402 | load symbol table information, if you want to be sure @value{GDBN} has the | |
5d161b24 | 13403 | entire symbol table available. |
c906108c | 13404 | |
c906108c SS |
13405 | @c FIXME: for now no mention of directories, since this seems to be in |
13406 | @c flux. 13mar1992 status is that in theory GDB would look either in | |
13407 | @c current dir or in same dir as myprog; but issues like competing | |
13408 | @c GDB's, or clutter in system dirs, mean that in practice right now | |
13409 | @c only current dir is used. FFish says maybe a special GDB hierarchy | |
13410 | @c (eg rooted in val of env var GDBSYMS) could exist for mappable symbol | |
13411 | @c files. | |
13412 | ||
c906108c | 13413 | @kindex core-file |
09d4efe1 | 13414 | @item core-file @r{[}@var{filename}@r{]} |
4644b6e3 | 13415 | @itemx core |
c906108c SS |
13416 | Specify the whereabouts of a core dump file to be used as the ``contents |
13417 | of memory''. Traditionally, core files contain only some parts of the | |
13418 | address space of the process that generated them; @value{GDBN} can access the | |
13419 | executable file itself for other parts. | |
13420 | ||
13421 | @code{core-file} with no argument specifies that no core file is | |
13422 | to be used. | |
13423 | ||
13424 | Note that the core file is ignored when your program is actually running | |
7a292a7a SS |
13425 | under @value{GDBN}. So, if you have been running your program and you |
13426 | wish to debug a core file instead, you must kill the subprocess in which | |
13427 | the program is running. To do this, use the @code{kill} command | |
79a6e687 | 13428 | (@pxref{Kill Process, ,Killing the Child Process}). |
c906108c | 13429 | |
c906108c SS |
13430 | @kindex add-symbol-file |
13431 | @cindex dynamic linking | |
13432 | @item add-symbol-file @var{filename} @var{address} | |
a94ab193 | 13433 | @itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]} |
17d9d558 | 13434 | @itemx add-symbol-file @var{filename} @r{-s}@var{section} @var{address} @dots{} |
96a2c332 SS |
13435 | The @code{add-symbol-file} command reads additional symbol table |
13436 | information from the file @var{filename}. You would use this command | |
13437 | when @var{filename} has been dynamically loaded (by some other means) | |
13438 | into the program that is running. @var{address} should be the memory | |
13439 | address at which the file has been loaded; @value{GDBN} cannot figure | |
d167840f EZ |
13440 | this out for itself. You can additionally specify an arbitrary number |
13441 | of @samp{@r{-s}@var{section} @var{address}} pairs, to give an explicit | |
13442 | section name and base address for that section. You can specify any | |
13443 | @var{address} as an expression. | |
c906108c SS |
13444 | |
13445 | The symbol table of the file @var{filename} is added to the symbol table | |
13446 | originally read with the @code{symbol-file} command. You can use the | |
96a2c332 SS |
13447 | @code{add-symbol-file} command any number of times; the new symbol data |
13448 | thus read keeps adding to the old. To discard all old symbol data | |
13449 | instead, use the @code{symbol-file} command without any arguments. | |
c906108c | 13450 | |
17d9d558 JB |
13451 | @cindex relocatable object files, reading symbols from |
13452 | @cindex object files, relocatable, reading symbols from | |
13453 | @cindex reading symbols from relocatable object files | |
13454 | @cindex symbols, reading from relocatable object files | |
13455 | @cindex @file{.o} files, reading symbols from | |
13456 | Although @var{filename} is typically a shared library file, an | |
13457 | executable file, or some other object file which has been fully | |
13458 | relocated for loading into a process, you can also load symbolic | |
13459 | information from relocatable @file{.o} files, as long as: | |
13460 | ||
13461 | @itemize @bullet | |
13462 | @item | |
13463 | the file's symbolic information refers only to linker symbols defined in | |
13464 | that file, not to symbols defined by other object files, | |
13465 | @item | |
13466 | every section the file's symbolic information refers to has actually | |
13467 | been loaded into the inferior, as it appears in the file, and | |
13468 | @item | |
13469 | you can determine the address at which every section was loaded, and | |
13470 | provide these to the @code{add-symbol-file} command. | |
13471 | @end itemize | |
13472 | ||
13473 | @noindent | |
13474 | Some embedded operating systems, like Sun Chorus and VxWorks, can load | |
13475 | relocatable files into an already running program; such systems | |
13476 | typically make the requirements above easy to meet. However, it's | |
13477 | important to recognize that many native systems use complex link | |
49efadf5 | 13478 | procedures (@code{.linkonce} section factoring and C@t{++} constructor table |
17d9d558 JB |
13479 | assembly, for example) that make the requirements difficult to meet. In |
13480 | general, one cannot assume that using @code{add-symbol-file} to read a | |
13481 | relocatable object file's symbolic information will have the same effect | |
13482 | as linking the relocatable object file into the program in the normal | |
13483 | way. | |
13484 | ||
c906108c SS |
13485 | @code{add-symbol-file} does not repeat if you press @key{RET} after using it. |
13486 | ||
c45da7e6 EZ |
13487 | @kindex add-symbol-file-from-memory |
13488 | @cindex @code{syscall DSO} | |
13489 | @cindex load symbols from memory | |
13490 | @item add-symbol-file-from-memory @var{address} | |
13491 | Load symbols from the given @var{address} in a dynamically loaded | |
13492 | object file whose image is mapped directly into the inferior's memory. | |
13493 | For example, the Linux kernel maps a @code{syscall DSO} into each | |
13494 | process's address space; this DSO provides kernel-specific code for | |
13495 | some system calls. The argument can be any expression whose | |
13496 | evaluation yields the address of the file's shared object file header. | |
13497 | For this command to work, you must have used @code{symbol-file} or | |
13498 | @code{exec-file} commands in advance. | |
13499 | ||
09d4efe1 EZ |
13500 | @kindex add-shared-symbol-files |
13501 | @kindex assf | |
13502 | @item add-shared-symbol-files @var{library-file} | |
13503 | @itemx assf @var{library-file} | |
13504 | The @code{add-shared-symbol-files} command can currently be used only | |
13505 | in the Cygwin build of @value{GDBN} on MS-Windows OS, where it is an | |
13506 | alias for the @code{dll-symbols} command (@pxref{Cygwin Native}). | |
13507 | @value{GDBN} automatically looks for shared libraries, however if | |
13508 | @value{GDBN} does not find yours, you can invoke | |
13509 | @code{add-shared-symbol-files}. It takes one argument: the shared | |
13510 | library's file name. @code{assf} is a shorthand alias for | |
13511 | @code{add-shared-symbol-files}. | |
c906108c | 13512 | |
c906108c | 13513 | @kindex section |
09d4efe1 EZ |
13514 | @item section @var{section} @var{addr} |
13515 | The @code{section} command changes the base address of the named | |
13516 | @var{section} of the exec file to @var{addr}. This can be used if the | |
13517 | exec file does not contain section addresses, (such as in the | |
13518 | @code{a.out} format), or when the addresses specified in the file | |
13519 | itself are wrong. Each section must be changed separately. The | |
13520 | @code{info files} command, described below, lists all the sections and | |
13521 | their addresses. | |
c906108c SS |
13522 | |
13523 | @kindex info files | |
13524 | @kindex info target | |
13525 | @item info files | |
13526 | @itemx info target | |
7a292a7a SS |
13527 | @code{info files} and @code{info target} are synonymous; both print the |
13528 | current target (@pxref{Targets, ,Specifying a Debugging Target}), | |
13529 | including the names of the executable and core dump files currently in | |
13530 | use by @value{GDBN}, and the files from which symbols were loaded. The | |
13531 | command @code{help target} lists all possible targets rather than | |
13532 | current ones. | |
13533 | ||
fe95c787 MS |
13534 | @kindex maint info sections |
13535 | @item maint info sections | |
13536 | Another command that can give you extra information about program sections | |
13537 | is @code{maint info sections}. In addition to the section information | |
13538 | displayed by @code{info files}, this command displays the flags and file | |
13539 | offset of each section in the executable and core dump files. In addition, | |
13540 | @code{maint info sections} provides the following command options (which | |
13541 | may be arbitrarily combined): | |
13542 | ||
13543 | @table @code | |
13544 | @item ALLOBJ | |
13545 | Display sections for all loaded object files, including shared libraries. | |
13546 | @item @var{sections} | |
6600abed | 13547 | Display info only for named @var{sections}. |
fe95c787 MS |
13548 | @item @var{section-flags} |
13549 | Display info only for sections for which @var{section-flags} are true. | |
13550 | The section flags that @value{GDBN} currently knows about are: | |
13551 | @table @code | |
13552 | @item ALLOC | |
13553 | Section will have space allocated in the process when loaded. | |
13554 | Set for all sections except those containing debug information. | |
13555 | @item LOAD | |
13556 | Section will be loaded from the file into the child process memory. | |
13557 | Set for pre-initialized code and data, clear for @code{.bss} sections. | |
13558 | @item RELOC | |
13559 | Section needs to be relocated before loading. | |
13560 | @item READONLY | |
13561 | Section cannot be modified by the child process. | |
13562 | @item CODE | |
13563 | Section contains executable code only. | |
6600abed | 13564 | @item DATA |
fe95c787 MS |
13565 | Section contains data only (no executable code). |
13566 | @item ROM | |
13567 | Section will reside in ROM. | |
13568 | @item CONSTRUCTOR | |
13569 | Section contains data for constructor/destructor lists. | |
13570 | @item HAS_CONTENTS | |
13571 | Section is not empty. | |
13572 | @item NEVER_LOAD | |
13573 | An instruction to the linker to not output the section. | |
13574 | @item COFF_SHARED_LIBRARY | |
13575 | A notification to the linker that the section contains | |
13576 | COFF shared library information. | |
13577 | @item IS_COMMON | |
13578 | Section contains common symbols. | |
13579 | @end table | |
13580 | @end table | |
6763aef9 | 13581 | @kindex set trust-readonly-sections |
9c16f35a | 13582 | @cindex read-only sections |
6763aef9 MS |
13583 | @item set trust-readonly-sections on |
13584 | Tell @value{GDBN} that readonly sections in your object file | |
6ca652b0 | 13585 | really are read-only (i.e.@: that their contents will not change). |
6763aef9 MS |
13586 | In that case, @value{GDBN} can fetch values from these sections |
13587 | out of the object file, rather than from the target program. | |
13588 | For some targets (notably embedded ones), this can be a significant | |
13589 | enhancement to debugging performance. | |
13590 | ||
13591 | The default is off. | |
13592 | ||
13593 | @item set trust-readonly-sections off | |
15110bc3 | 13594 | Tell @value{GDBN} not to trust readonly sections. This means that |
6763aef9 MS |
13595 | the contents of the section might change while the program is running, |
13596 | and must therefore be fetched from the target when needed. | |
9c16f35a EZ |
13597 | |
13598 | @item show trust-readonly-sections | |
13599 | Show the current setting of trusting readonly sections. | |
c906108c SS |
13600 | @end table |
13601 | ||
13602 | All file-specifying commands allow both absolute and relative file names | |
13603 | as arguments. @value{GDBN} always converts the file name to an absolute file | |
13604 | name and remembers it that way. | |
13605 | ||
c906108c | 13606 | @cindex shared libraries |
9cceb671 DJ |
13607 | @anchor{Shared Libraries} |
13608 | @value{GDBN} supports @sc{gnu}/Linux, MS-Windows, HP-UX, SunOS, SVr4, Irix, | |
9c16f35a | 13609 | and IBM RS/6000 AIX shared libraries. |
53a5351d | 13610 | |
9cceb671 DJ |
13611 | On MS-Windows @value{GDBN} must be linked with the Expat library to support |
13612 | shared libraries. @xref{Expat}. | |
13613 | ||
c906108c SS |
13614 | @value{GDBN} automatically loads symbol definitions from shared libraries |
13615 | when you use the @code{run} command, or when you examine a core file. | |
13616 | (Before you issue the @code{run} command, @value{GDBN} does not understand | |
13617 | references to a function in a shared library, however---unless you are | |
13618 | debugging a core file). | |
53a5351d JM |
13619 | |
13620 | On HP-UX, if the program loads a library explicitly, @value{GDBN} | |
13621 | automatically loads the symbols at the time of the @code{shl_load} call. | |
13622 | ||
c906108c SS |
13623 | @c FIXME: some @value{GDBN} release may permit some refs to undef |
13624 | @c FIXME...symbols---eg in a break cmd---assuming they are from a shared | |
13625 | @c FIXME...lib; check this from time to time when updating manual | |
13626 | ||
b7209cb4 FF |
13627 | There are times, however, when you may wish to not automatically load |
13628 | symbol definitions from shared libraries, such as when they are | |
13629 | particularly large or there are many of them. | |
13630 | ||
13631 | To control the automatic loading of shared library symbols, use the | |
13632 | commands: | |
13633 | ||
13634 | @table @code | |
13635 | @kindex set auto-solib-add | |
13636 | @item set auto-solib-add @var{mode} | |
13637 | If @var{mode} is @code{on}, symbols from all shared object libraries | |
13638 | will be loaded automatically when the inferior begins execution, you | |
13639 | attach to an independently started inferior, or when the dynamic linker | |
13640 | informs @value{GDBN} that a new library has been loaded. If @var{mode} | |
13641 | is @code{off}, symbols must be loaded manually, using the | |
13642 | @code{sharedlibrary} command. The default value is @code{on}. | |
13643 | ||
dcaf7c2c EZ |
13644 | @cindex memory used for symbol tables |
13645 | If your program uses lots of shared libraries with debug info that | |
13646 | takes large amounts of memory, you can decrease the @value{GDBN} | |
13647 | memory footprint by preventing it from automatically loading the | |
13648 | symbols from shared libraries. To that end, type @kbd{set | |
13649 | auto-solib-add off} before running the inferior, then load each | |
13650 | library whose debug symbols you do need with @kbd{sharedlibrary | |
d3e8051b | 13651 | @var{regexp}}, where @var{regexp} is a regular expression that matches |
dcaf7c2c EZ |
13652 | the libraries whose symbols you want to be loaded. |
13653 | ||
b7209cb4 FF |
13654 | @kindex show auto-solib-add |
13655 | @item show auto-solib-add | |
13656 | Display the current autoloading mode. | |
13657 | @end table | |
13658 | ||
c45da7e6 | 13659 | @cindex load shared library |
b7209cb4 FF |
13660 | To explicitly load shared library symbols, use the @code{sharedlibrary} |
13661 | command: | |
13662 | ||
c906108c SS |
13663 | @table @code |
13664 | @kindex info sharedlibrary | |
13665 | @kindex info share | |
55333a84 DE |
13666 | @item info share @var{regex} |
13667 | @itemx info sharedlibrary @var{regex} | |
13668 | Print the names of the shared libraries which are currently loaded | |
13669 | that match @var{regex}. If @var{regex} is omitted then print | |
13670 | all shared libraries that are loaded. | |
c906108c SS |
13671 | |
13672 | @kindex sharedlibrary | |
13673 | @kindex share | |
13674 | @item sharedlibrary @var{regex} | |
13675 | @itemx share @var{regex} | |
c906108c SS |
13676 | Load shared object library symbols for files matching a |
13677 | Unix regular expression. | |
13678 | As with files loaded automatically, it only loads shared libraries | |
13679 | required by your program for a core file or after typing @code{run}. If | |
13680 | @var{regex} is omitted all shared libraries required by your program are | |
13681 | loaded. | |
c45da7e6 EZ |
13682 | |
13683 | @item nosharedlibrary | |
13684 | @kindex nosharedlibrary | |
13685 | @cindex unload symbols from shared libraries | |
13686 | Unload all shared object library symbols. This discards all symbols | |
13687 | that have been loaded from all shared libraries. Symbols from shared | |
13688 | libraries that were loaded by explicit user requests are not | |
13689 | discarded. | |
c906108c SS |
13690 | @end table |
13691 | ||
721c2651 EZ |
13692 | Sometimes you may wish that @value{GDBN} stops and gives you control |
13693 | when any of shared library events happen. Use the @code{set | |
13694 | stop-on-solib-events} command for this: | |
13695 | ||
13696 | @table @code | |
13697 | @item set stop-on-solib-events | |
13698 | @kindex set stop-on-solib-events | |
13699 | This command controls whether @value{GDBN} should give you control | |
13700 | when the dynamic linker notifies it about some shared library event. | |
13701 | The most common event of interest is loading or unloading of a new | |
13702 | shared library. | |
13703 | ||
13704 | @item show stop-on-solib-events | |
13705 | @kindex show stop-on-solib-events | |
13706 | Show whether @value{GDBN} stops and gives you control when shared | |
13707 | library events happen. | |
13708 | @end table | |
13709 | ||
f5ebfba0 | 13710 | Shared libraries are also supported in many cross or remote debugging |
f1838a98 UW |
13711 | configurations. @value{GDBN} needs to have access to the target's libraries; |
13712 | this can be accomplished either by providing copies of the libraries | |
13713 | on the host system, or by asking @value{GDBN} to automatically retrieve the | |
13714 | libraries from the target. If copies of the target libraries are | |
13715 | provided, they need to be the same as the target libraries, although the | |
f5ebfba0 DJ |
13716 | copies on the target can be stripped as long as the copies on the host are |
13717 | not. | |
13718 | ||
59b7b46f EZ |
13719 | @cindex where to look for shared libraries |
13720 | For remote debugging, you need to tell @value{GDBN} where the target | |
13721 | libraries are, so that it can load the correct copies---otherwise, it | |
13722 | may try to load the host's libraries. @value{GDBN} has two variables | |
13723 | to specify the search directories for target libraries. | |
f5ebfba0 DJ |
13724 | |
13725 | @table @code | |
59b7b46f | 13726 | @cindex prefix for shared library file names |
f822c95b | 13727 | @cindex system root, alternate |
f5ebfba0 | 13728 | @kindex set solib-absolute-prefix |
f822c95b DJ |
13729 | @kindex set sysroot |
13730 | @item set sysroot @var{path} | |
13731 | Use @var{path} as the system root for the program being debugged. Any | |
13732 | absolute shared library paths will be prefixed with @var{path}; many | |
13733 | runtime loaders store the absolute paths to the shared library in the | |
13734 | target program's memory. If you use @code{set sysroot} to find shared | |
13735 | libraries, they need to be laid out in the same way that they are on | |
13736 | the target, with e.g.@: a @file{/lib} and @file{/usr/lib} hierarchy | |
13737 | under @var{path}. | |
13738 | ||
f1838a98 UW |
13739 | If @var{path} starts with the sequence @file{remote:}, @value{GDBN} will |
13740 | retrieve the target libraries from the remote system. This is only | |
13741 | supported when using a remote target that supports the @code{remote get} | |
13742 | command (@pxref{File Transfer,,Sending files to a remote system}). | |
13743 | The part of @var{path} following the initial @file{remote:} | |
13744 | (if present) is used as system root prefix on the remote file system. | |
13745 | @footnote{If you want to specify a local system root using a directory | |
13746 | that happens to be named @file{remote:}, you need to use some equivalent | |
13747 | variant of the name like @file{./remote:}.} | |
13748 | ||
f822c95b DJ |
13749 | The @code{set solib-absolute-prefix} command is an alias for @code{set |
13750 | sysroot}. | |
13751 | ||
13752 | @cindex default system root | |
59b7b46f | 13753 | @cindex @samp{--with-sysroot} |
f822c95b DJ |
13754 | You can set the default system root by using the configure-time |
13755 | @samp{--with-sysroot} option. If the system root is inside | |
13756 | @value{GDBN}'s configured binary prefix (set with @samp{--prefix} or | |
13757 | @samp{--exec-prefix}), then the default system root will be updated | |
13758 | automatically if the installed @value{GDBN} is moved to a new | |
13759 | location. | |
13760 | ||
13761 | @kindex show sysroot | |
13762 | @item show sysroot | |
f5ebfba0 DJ |
13763 | Display the current shared library prefix. |
13764 | ||
13765 | @kindex set solib-search-path | |
13766 | @item set solib-search-path @var{path} | |
f822c95b DJ |
13767 | If this variable is set, @var{path} is a colon-separated list of |
13768 | directories to search for shared libraries. @samp{solib-search-path} | |
13769 | is used after @samp{sysroot} fails to locate the library, or if the | |
13770 | path to the library is relative instead of absolute. If you want to | |
13771 | use @samp{solib-search-path} instead of @samp{sysroot}, be sure to set | |
d3e8051b | 13772 | @samp{sysroot} to a nonexistent directory to prevent @value{GDBN} from |
f822c95b | 13773 | finding your host's libraries. @samp{sysroot} is preferred; setting |
d3e8051b | 13774 | it to a nonexistent directory may interfere with automatic loading |
f822c95b | 13775 | of shared library symbols. |
f5ebfba0 DJ |
13776 | |
13777 | @kindex show solib-search-path | |
13778 | @item show solib-search-path | |
13779 | Display the current shared library search path. | |
13780 | @end table | |
13781 | ||
5b5d99cf JB |
13782 | |
13783 | @node Separate Debug Files | |
13784 | @section Debugging Information in Separate Files | |
13785 | @cindex separate debugging information files | |
13786 | @cindex debugging information in separate files | |
13787 | @cindex @file{.debug} subdirectories | |
13788 | @cindex debugging information directory, global | |
13789 | @cindex global debugging information directory | |
c7e83d54 EZ |
13790 | @cindex build ID, and separate debugging files |
13791 | @cindex @file{.build-id} directory | |
5b5d99cf JB |
13792 | |
13793 | @value{GDBN} allows you to put a program's debugging information in a | |
13794 | file separate from the executable itself, in a way that allows | |
13795 | @value{GDBN} to find and load the debugging information automatically. | |
c7e83d54 EZ |
13796 | Since debugging information can be very large---sometimes larger |
13797 | than the executable code itself---some systems distribute debugging | |
5b5d99cf JB |
13798 | information for their executables in separate files, which users can |
13799 | install only when they need to debug a problem. | |
13800 | ||
c7e83d54 EZ |
13801 | @value{GDBN} supports two ways of specifying the separate debug info |
13802 | file: | |
5b5d99cf JB |
13803 | |
13804 | @itemize @bullet | |
13805 | @item | |
c7e83d54 EZ |
13806 | The executable contains a @dfn{debug link} that specifies the name of |
13807 | the separate debug info file. The separate debug file's name is | |
13808 | usually @file{@var{executable}.debug}, where @var{executable} is the | |
13809 | name of the corresponding executable file without leading directories | |
13810 | (e.g., @file{ls.debug} for @file{/usr/bin/ls}). In addition, the | |
99e008fe EZ |
13811 | debug link specifies a 32-bit @dfn{Cyclic Redundancy Check} (CRC) |
13812 | checksum for the debug file, which @value{GDBN} uses to validate that | |
13813 | the executable and the debug file came from the same build. | |
c7e83d54 EZ |
13814 | |
13815 | @item | |
7e27a47a | 13816 | The executable contains a @dfn{build ID}, a unique bit string that is |
c7e83d54 | 13817 | also present in the corresponding debug info file. (This is supported |
7e27a47a EZ |
13818 | only on some operating systems, notably those which use the ELF format |
13819 | for binary files and the @sc{gnu} Binutils.) For more details about | |
13820 | this feature, see the description of the @option{--build-id} | |
13821 | command-line option in @ref{Options, , Command Line Options, ld.info, | |
13822 | The GNU Linker}. The debug info file's name is not specified | |
13823 | explicitly by the build ID, but can be computed from the build ID, see | |
13824 | below. | |
d3750b24 JK |
13825 | @end itemize |
13826 | ||
c7e83d54 EZ |
13827 | Depending on the way the debug info file is specified, @value{GDBN} |
13828 | uses two different methods of looking for the debug file: | |
d3750b24 JK |
13829 | |
13830 | @itemize @bullet | |
13831 | @item | |
c7e83d54 EZ |
13832 | For the ``debug link'' method, @value{GDBN} looks up the named file in |
13833 | the directory of the executable file, then in a subdirectory of that | |
13834 | directory named @file{.debug}, and finally under the global debug | |
13835 | directory, in a subdirectory whose name is identical to the leading | |
13836 | directories of the executable's absolute file name. | |
13837 | ||
13838 | @item | |
83f83d7f | 13839 | For the ``build ID'' method, @value{GDBN} looks in the |
c7e83d54 EZ |
13840 | @file{.build-id} subdirectory of the global debug directory for a file |
13841 | named @file{@var{nn}/@var{nnnnnnnn}.debug}, where @var{nn} are the | |
7e27a47a EZ |
13842 | first 2 hex characters of the build ID bit string, and @var{nnnnnnnn} |
13843 | are the rest of the bit string. (Real build ID strings are 32 or more | |
13844 | hex characters, not 10.) | |
c7e83d54 EZ |
13845 | @end itemize |
13846 | ||
13847 | So, for example, suppose you ask @value{GDBN} to debug | |
7e27a47a EZ |
13848 | @file{/usr/bin/ls}, which has a debug link that specifies the |
13849 | file @file{ls.debug}, and a build ID whose value in hex is | |
c7e83d54 EZ |
13850 | @code{abcdef1234}. If the global debug directory is |
13851 | @file{/usr/lib/debug}, then @value{GDBN} will look for the following | |
13852 | debug information files, in the indicated order: | |
13853 | ||
13854 | @itemize @minus | |
13855 | @item | |
13856 | @file{/usr/lib/debug/.build-id/ab/cdef1234.debug} | |
d3750b24 | 13857 | @item |
c7e83d54 | 13858 | @file{/usr/bin/ls.debug} |
5b5d99cf | 13859 | @item |
c7e83d54 | 13860 | @file{/usr/bin/.debug/ls.debug} |
5b5d99cf | 13861 | @item |
c7e83d54 | 13862 | @file{/usr/lib/debug/usr/bin/ls.debug}. |
5b5d99cf | 13863 | @end itemize |
5b5d99cf JB |
13864 | |
13865 | You can set the global debugging info directory's name, and view the | |
13866 | name @value{GDBN} is currently using. | |
13867 | ||
13868 | @table @code | |
13869 | ||
13870 | @kindex set debug-file-directory | |
13871 | @item set debug-file-directory @var{directory} | |
13872 | Set the directory which @value{GDBN} searches for separate debugging | |
13873 | information files to @var{directory}. | |
13874 | ||
13875 | @kindex show debug-file-directory | |
13876 | @item show debug-file-directory | |
13877 | Show the directory @value{GDBN} searches for separate debugging | |
13878 | information files. | |
13879 | ||
13880 | @end table | |
13881 | ||
13882 | @cindex @code{.gnu_debuglink} sections | |
c7e83d54 | 13883 | @cindex debug link sections |
5b5d99cf JB |
13884 | A debug link is a special section of the executable file named |
13885 | @code{.gnu_debuglink}. The section must contain: | |
13886 | ||
13887 | @itemize | |
13888 | @item | |
13889 | A filename, with any leading directory components removed, followed by | |
13890 | a zero byte, | |
13891 | @item | |
13892 | zero to three bytes of padding, as needed to reach the next four-byte | |
13893 | boundary within the section, and | |
13894 | @item | |
13895 | a four-byte CRC checksum, stored in the same endianness used for the | |
13896 | executable file itself. The checksum is computed on the debugging | |
13897 | information file's full contents by the function given below, passing | |
13898 | zero as the @var{crc} argument. | |
13899 | @end itemize | |
13900 | ||
13901 | Any executable file format can carry a debug link, as long as it can | |
13902 | contain a section named @code{.gnu_debuglink} with the contents | |
13903 | described above. | |
13904 | ||
d3750b24 | 13905 | @cindex @code{.note.gnu.build-id} sections |
c7e83d54 | 13906 | @cindex build ID sections |
7e27a47a EZ |
13907 | The build ID is a special section in the executable file (and in other |
13908 | ELF binary files that @value{GDBN} may consider). This section is | |
13909 | often named @code{.note.gnu.build-id}, but that name is not mandatory. | |
13910 | It contains unique identification for the built files---the ID remains | |
13911 | the same across multiple builds of the same build tree. The default | |
13912 | algorithm SHA1 produces 160 bits (40 hexadecimal characters) of the | |
13913 | content for the build ID string. The same section with an identical | |
13914 | value is present in the original built binary with symbols, in its | |
13915 | stripped variant, and in the separate debugging information file. | |
d3750b24 | 13916 | |
5b5d99cf JB |
13917 | The debugging information file itself should be an ordinary |
13918 | executable, containing a full set of linker symbols, sections, and | |
13919 | debugging information. The sections of the debugging information file | |
c7e83d54 EZ |
13920 | should have the same names, addresses, and sizes as the original file, |
13921 | but they need not contain any data---much like a @code{.bss} section | |
5b5d99cf JB |
13922 | in an ordinary executable. |
13923 | ||
7e27a47a | 13924 | The @sc{gnu} binary utilities (Binutils) package includes the |
c7e83d54 EZ |
13925 | @samp{objcopy} utility that can produce |
13926 | the separated executable / debugging information file pairs using the | |
13927 | following commands: | |
13928 | ||
13929 | @smallexample | |
13930 | @kbd{objcopy --only-keep-debug foo foo.debug} | |
13931 | @kbd{strip -g foo} | |
c7e83d54 EZ |
13932 | @end smallexample |
13933 | ||
13934 | @noindent | |
13935 | These commands remove the debugging | |
83f83d7f JK |
13936 | information from the executable file @file{foo} and place it in the file |
13937 | @file{foo.debug}. You can use the first, second or both methods to link the | |
13938 | two files: | |
13939 | ||
13940 | @itemize @bullet | |
13941 | @item | |
13942 | The debug link method needs the following additional command to also leave | |
13943 | behind a debug link in @file{foo}: | |
13944 | ||
13945 | @smallexample | |
13946 | @kbd{objcopy --add-gnu-debuglink=foo.debug foo} | |
13947 | @end smallexample | |
13948 | ||
13949 | Ulrich Drepper's @file{elfutils} package, starting with version 0.53, contains | |
d3750b24 | 13950 | a version of the @code{strip} command such that the command @kbd{strip foo -f |
83f83d7f JK |
13951 | foo.debug} has the same functionality as the two @code{objcopy} commands and |
13952 | the @code{ln -s} command above, together. | |
13953 | ||
13954 | @item | |
13955 | Build ID gets embedded into the main executable using @code{ld --build-id} or | |
13956 | the @value{NGCC} counterpart @code{gcc -Wl,--build-id}. Build ID support plus | |
13957 | compatibility fixes for debug files separation are present in @sc{gnu} binary | |
7e27a47a | 13958 | utilities (Binutils) package since version 2.18. |
83f83d7f JK |
13959 | @end itemize |
13960 | ||
13961 | @noindent | |
d3750b24 | 13962 | |
99e008fe EZ |
13963 | @cindex CRC algorithm definition |
13964 | The CRC used in @code{.gnu_debuglink} is the CRC-32 defined in | |
13965 | IEEE 802.3 using the polynomial: | |
13966 | ||
13967 | @c TexInfo requires naked braces for multi-digit exponents for Tex | |
13968 | @c output, but this causes HTML output to barf. HTML has to be set using | |
13969 | @c raw commands. So we end up having to specify this equation in 2 | |
13970 | @c different ways! | |
13971 | @ifhtml | |
13972 | @display | |
13973 | @html | |
13974 | <em>x</em><sup>32</sup> + <em>x</em><sup>26</sup> + <em>x</em><sup>23</sup> + <em>x</em><sup>22</sup> + <em>x</em><sup>16</sup> + <em>x</em><sup>12</sup> + <em>x</em><sup>11</sup> | |
13975 | + <em>x</em><sup>10</sup> + <em>x</em><sup>8</sup> + <em>x</em><sup>7</sup> + <em>x</em><sup>5</sup> + <em>x</em><sup>4</sup> + <em>x</em><sup>2</sup> + <em>x</em> + 1 | |
13976 | @end html | |
13977 | @end display | |
13978 | @end ifhtml | |
13979 | @ifnothtml | |
13980 | @display | |
13981 | @math{x^{32} + x^{26} + x^{23} + x^{22} + x^{16} + x^{12} + x^{11}} | |
13982 | @math{+ x^{10} + x^8 + x^7 + x^5 + x^4 + x^2 + x + 1} | |
13983 | @end display | |
13984 | @end ifnothtml | |
13985 | ||
13986 | The function is computed byte at a time, taking the least | |
13987 | significant bit of each byte first. The initial pattern | |
13988 | @code{0xffffffff} is used, to ensure leading zeros affect the CRC and | |
13989 | the final result is inverted to ensure trailing zeros also affect the | |
13990 | CRC. | |
13991 | ||
13992 | @emph{Note:} This is the same CRC polynomial as used in handling the | |
13993 | @dfn{Remote Serial Protocol} @code{qCRC} packet (@pxref{Remote Protocol, | |
13994 | , @value{GDBN} Remote Serial Protocol}). However in the | |
13995 | case of the Remote Serial Protocol, the CRC is computed @emph{most} | |
13996 | significant bit first, and the result is not inverted, so trailing | |
13997 | zeros have no effect on the CRC value. | |
13998 | ||
13999 | To complete the description, we show below the code of the function | |
14000 | which produces the CRC used in @code{.gnu_debuglink}. Inverting the | |
14001 | initially supplied @code{crc} argument means that an initial call to | |
14002 | this function passing in zero will start computing the CRC using | |
14003 | @code{0xffffffff}. | |
5b5d99cf | 14004 | |
4644b6e3 | 14005 | @kindex gnu_debuglink_crc32 |
5b5d99cf JB |
14006 | @smallexample |
14007 | unsigned long | |
14008 | gnu_debuglink_crc32 (unsigned long crc, | |
14009 | unsigned char *buf, size_t len) | |
14010 | @{ | |
14011 | static const unsigned long crc32_table[256] = | |
14012 | @{ | |
14013 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, | |
14014 | 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, | |
14015 | 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, | |
14016 | 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, | |
14017 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, | |
14018 | 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, | |
14019 | 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, | |
14020 | 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, | |
14021 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, | |
14022 | 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, | |
14023 | 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, | |
14024 | 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, | |
14025 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, | |
14026 | 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, | |
14027 | 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, | |
14028 | 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, | |
14029 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, | |
14030 | 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, | |
14031 | 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, | |
14032 | 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, | |
14033 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, | |
14034 | 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, | |
14035 | 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, | |
14036 | 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, | |
14037 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, | |
14038 | 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, | |
14039 | 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, | |
14040 | 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, | |
14041 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, | |
14042 | 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, | |
14043 | 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, | |
14044 | 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, | |
14045 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, | |
14046 | 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, | |
14047 | 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, | |
14048 | 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, | |
14049 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, | |
14050 | 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, | |
14051 | 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, | |
14052 | 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, | |
14053 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, | |
14054 | 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, | |
14055 | 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, | |
14056 | 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, | |
14057 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, | |
14058 | 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, | |
14059 | 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, | |
14060 | 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, | |
14061 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, | |
14062 | 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, | |
14063 | 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, | |
14064 | 0x2d02ef8d | |
14065 | @}; | |
14066 | unsigned char *end; | |
14067 | ||
14068 | crc = ~crc & 0xffffffff; | |
14069 | for (end = buf + len; buf < end; ++buf) | |
14070 | crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8); | |
e7a3abfc | 14071 | return ~crc & 0xffffffff; |
5b5d99cf JB |
14072 | @} |
14073 | @end smallexample | |
14074 | ||
c7e83d54 EZ |
14075 | @noindent |
14076 | This computation does not apply to the ``build ID'' method. | |
14077 | ||
5b5d99cf | 14078 | |
6d2ebf8b | 14079 | @node Symbol Errors |
79a6e687 | 14080 | @section Errors Reading Symbol Files |
c906108c SS |
14081 | |
14082 | While reading a symbol file, @value{GDBN} occasionally encounters problems, | |
14083 | such as symbol types it does not recognize, or known bugs in compiler | |
14084 | output. By default, @value{GDBN} does not notify you of such problems, since | |
14085 | they are relatively common and primarily of interest to people | |
14086 | debugging compilers. If you are interested in seeing information | |
14087 | about ill-constructed symbol tables, you can either ask @value{GDBN} to print | |
14088 | only one message about each such type of problem, no matter how many | |
14089 | times the problem occurs; or you can ask @value{GDBN} to print more messages, | |
14090 | to see how many times the problems occur, with the @code{set | |
79a6e687 BW |
14091 | complaints} command (@pxref{Messages/Warnings, ,Optional Warnings and |
14092 | Messages}). | |
c906108c SS |
14093 | |
14094 | The messages currently printed, and their meanings, include: | |
14095 | ||
14096 | @table @code | |
14097 | @item inner block not inside outer block in @var{symbol} | |
14098 | ||
14099 | The symbol information shows where symbol scopes begin and end | |
14100 | (such as at the start of a function or a block of statements). This | |
14101 | error indicates that an inner scope block is not fully contained | |
14102 | in its outer scope blocks. | |
14103 | ||
14104 | @value{GDBN} circumvents the problem by treating the inner block as if it had | |
14105 | the same scope as the outer block. In the error message, @var{symbol} | |
14106 | may be shown as ``@code{(don't know)}'' if the outer block is not a | |
14107 | function. | |
14108 | ||
14109 | @item block at @var{address} out of order | |
14110 | ||
14111 | The symbol information for symbol scope blocks should occur in | |
14112 | order of increasing addresses. This error indicates that it does not | |
14113 | do so. | |
14114 | ||
14115 | @value{GDBN} does not circumvent this problem, and has trouble | |
14116 | locating symbols in the source file whose symbols it is reading. (You | |
14117 | can often determine what source file is affected by specifying | |
79a6e687 BW |
14118 | @code{set verbose on}. @xref{Messages/Warnings, ,Optional Warnings and |
14119 | Messages}.) | |
c906108c SS |
14120 | |
14121 | @item bad block start address patched | |
14122 | ||
14123 | The symbol information for a symbol scope block has a start address | |
14124 | smaller than the address of the preceding source line. This is known | |
14125 | to occur in the SunOS 4.1.1 (and earlier) C compiler. | |
14126 | ||
14127 | @value{GDBN} circumvents the problem by treating the symbol scope block as | |
14128 | starting on the previous source line. | |
14129 | ||
14130 | @item bad string table offset in symbol @var{n} | |
14131 | ||
14132 | @cindex foo | |
14133 | Symbol number @var{n} contains a pointer into the string table which is | |
14134 | larger than the size of the string table. | |
14135 | ||
14136 | @value{GDBN} circumvents the problem by considering the symbol to have the | |
14137 | name @code{foo}, which may cause other problems if many symbols end up | |
14138 | with this name. | |
14139 | ||
14140 | @item unknown symbol type @code{0x@var{nn}} | |
14141 | ||
7a292a7a SS |
14142 | The symbol information contains new data types that @value{GDBN} does |
14143 | not yet know how to read. @code{0x@var{nn}} is the symbol type of the | |
d4f3574e | 14144 | uncomprehended information, in hexadecimal. |
c906108c | 14145 | |
7a292a7a SS |
14146 | @value{GDBN} circumvents the error by ignoring this symbol information. |
14147 | This usually allows you to debug your program, though certain symbols | |
c906108c | 14148 | are not accessible. If you encounter such a problem and feel like |
7a292a7a SS |
14149 | debugging it, you can debug @code{@value{GDBP}} with itself, breakpoint |
14150 | on @code{complain}, then go up to the function @code{read_dbx_symtab} | |
14151 | and examine @code{*bufp} to see the symbol. | |
c906108c SS |
14152 | |
14153 | @item stub type has NULL name | |
c906108c | 14154 | |
7a292a7a | 14155 | @value{GDBN} could not find the full definition for a struct or class. |
c906108c | 14156 | |
7a292a7a | 14157 | @item const/volatile indicator missing (ok if using g++ v1.x), got@dots{} |
b37052ae | 14158 | The symbol information for a C@t{++} member function is missing some |
7a292a7a SS |
14159 | information that recent versions of the compiler should have output for |
14160 | it. | |
c906108c SS |
14161 | |
14162 | @item info mismatch between compiler and debugger | |
14163 | ||
14164 | @value{GDBN} could not parse a type specification output by the compiler. | |
7a292a7a | 14165 | |
c906108c SS |
14166 | @end table |
14167 | ||
b14b1491 TT |
14168 | @node Data Files |
14169 | @section GDB Data Files | |
14170 | ||
14171 | @cindex prefix for data files | |
14172 | @value{GDBN} will sometimes read an auxiliary data file. These files | |
14173 | are kept in a directory known as the @dfn{data directory}. | |
14174 | ||
14175 | You can set the data directory's name, and view the name @value{GDBN} | |
14176 | is currently using. | |
14177 | ||
14178 | @table @code | |
14179 | @kindex set data-directory | |
14180 | @item set data-directory @var{directory} | |
14181 | Set the directory which @value{GDBN} searches for auxiliary data files | |
14182 | to @var{directory}. | |
14183 | ||
14184 | @kindex show data-directory | |
14185 | @item show data-directory | |
14186 | Show the directory @value{GDBN} searches for auxiliary data files. | |
14187 | @end table | |
14188 | ||
14189 | @cindex default data directory | |
14190 | @cindex @samp{--with-gdb-datadir} | |
14191 | You can set the default data directory by using the configure-time | |
14192 | @samp{--with-gdb-datadir} option. If the data directory is inside | |
14193 | @value{GDBN}'s configured binary prefix (set with @samp{--prefix} or | |
14194 | @samp{--exec-prefix}), then the default data directory will be updated | |
14195 | automatically if the installed @value{GDBN} is moved to a new | |
14196 | location. | |
14197 | ||
6d2ebf8b | 14198 | @node Targets |
c906108c | 14199 | @chapter Specifying a Debugging Target |
7a292a7a | 14200 | |
c906108c | 14201 | @cindex debugging target |
c906108c | 14202 | A @dfn{target} is the execution environment occupied by your program. |
53a5351d JM |
14203 | |
14204 | Often, @value{GDBN} runs in the same host environment as your program; | |
14205 | in that case, the debugging target is specified as a side effect when | |
14206 | you use the @code{file} or @code{core} commands. When you need more | |
c906108c SS |
14207 | flexibility---for example, running @value{GDBN} on a physically separate |
14208 | host, or controlling a standalone system over a serial port or a | |
53a5351d JM |
14209 | realtime system over a TCP/IP connection---you can use the @code{target} |
14210 | command to specify one of the target types configured for @value{GDBN} | |
79a6e687 | 14211 | (@pxref{Target Commands, ,Commands for Managing Targets}). |
c906108c | 14212 | |
a8f24a35 EZ |
14213 | @cindex target architecture |
14214 | It is possible to build @value{GDBN} for several different @dfn{target | |
14215 | architectures}. When @value{GDBN} is built like that, you can choose | |
14216 | one of the available architectures with the @kbd{set architecture} | |
14217 | command. | |
14218 | ||
14219 | @table @code | |
14220 | @kindex set architecture | |
14221 | @kindex show architecture | |
14222 | @item set architecture @var{arch} | |
14223 | This command sets the current target architecture to @var{arch}. The | |
14224 | value of @var{arch} can be @code{"auto"}, in addition to one of the | |
14225 | supported architectures. | |
14226 | ||
14227 | @item show architecture | |
14228 | Show the current target architecture. | |
9c16f35a EZ |
14229 | |
14230 | @item set processor | |
14231 | @itemx processor | |
14232 | @kindex set processor | |
14233 | @kindex show processor | |
14234 | These are alias commands for, respectively, @code{set architecture} | |
14235 | and @code{show architecture}. | |
a8f24a35 EZ |
14236 | @end table |
14237 | ||
c906108c SS |
14238 | @menu |
14239 | * Active Targets:: Active targets | |
14240 | * Target Commands:: Commands for managing targets | |
c906108c | 14241 | * Byte Order:: Choosing target byte order |
c906108c SS |
14242 | @end menu |
14243 | ||
6d2ebf8b | 14244 | @node Active Targets |
79a6e687 | 14245 | @section Active Targets |
7a292a7a | 14246 | |
c906108c SS |
14247 | @cindex stacking targets |
14248 | @cindex active targets | |
14249 | @cindex multiple targets | |
14250 | ||
c906108c | 14251 | There are three classes of targets: processes, core files, and |
7a292a7a SS |
14252 | executable files. @value{GDBN} can work concurrently on up to three |
14253 | active targets, one in each class. This allows you to (for example) | |
14254 | start a process and inspect its activity without abandoning your work on | |
14255 | a core file. | |
c906108c SS |
14256 | |
14257 | For example, if you execute @samp{gdb a.out}, then the executable file | |
14258 | @code{a.out} is the only active target. If you designate a core file as | |
14259 | well---presumably from a prior run that crashed and coredumped---then | |
14260 | @value{GDBN} has two active targets and uses them in tandem, looking | |
14261 | first in the corefile target, then in the executable file, to satisfy | |
14262 | requests for memory addresses. (Typically, these two classes of target | |
14263 | are complementary, since core files contain only a program's | |
14264 | read-write memory---variables and so on---plus machine status, while | |
14265 | executable files contain only the program text and initialized data.) | |
c906108c SS |
14266 | |
14267 | When you type @code{run}, your executable file becomes an active process | |
7a292a7a SS |
14268 | target as well. When a process target is active, all @value{GDBN} |
14269 | commands requesting memory addresses refer to that target; addresses in | |
14270 | an active core file or executable file target are obscured while the | |
14271 | process target is active. | |
c906108c | 14272 | |
7a292a7a | 14273 | Use the @code{core-file} and @code{exec-file} commands to select a new |
79a6e687 BW |
14274 | core file or executable target (@pxref{Files, ,Commands to Specify |
14275 | Files}). To specify as a target a process that is already running, use | |
14276 | the @code{attach} command (@pxref{Attach, ,Debugging an Already-running | |
14277 | Process}). | |
c906108c | 14278 | |
6d2ebf8b | 14279 | @node Target Commands |
79a6e687 | 14280 | @section Commands for Managing Targets |
c906108c SS |
14281 | |
14282 | @table @code | |
14283 | @item target @var{type} @var{parameters} | |
7a292a7a SS |
14284 | Connects the @value{GDBN} host environment to a target machine or |
14285 | process. A target is typically a protocol for talking to debugging | |
14286 | facilities. You use the argument @var{type} to specify the type or | |
14287 | protocol of the target machine. | |
c906108c SS |
14288 | |
14289 | Further @var{parameters} are interpreted by the target protocol, but | |
14290 | typically include things like device names or host names to connect | |
14291 | with, process numbers, and baud rates. | |
c906108c SS |
14292 | |
14293 | The @code{target} command does not repeat if you press @key{RET} again | |
14294 | after executing the command. | |
14295 | ||
14296 | @kindex help target | |
14297 | @item help target | |
14298 | Displays the names of all targets available. To display targets | |
14299 | currently selected, use either @code{info target} or @code{info files} | |
79a6e687 | 14300 | (@pxref{Files, ,Commands to Specify Files}). |
c906108c SS |
14301 | |
14302 | @item help target @var{name} | |
14303 | Describe a particular target, including any parameters necessary to | |
14304 | select it. | |
14305 | ||
14306 | @kindex set gnutarget | |
14307 | @item set gnutarget @var{args} | |
5d161b24 | 14308 | @value{GDBN} uses its own library BFD to read your files. @value{GDBN} |
c906108c | 14309 | knows whether it is reading an @dfn{executable}, |
5d161b24 DB |
14310 | a @dfn{core}, or a @dfn{.o} file; however, you can specify the file format |
14311 | with the @code{set gnutarget} command. Unlike most @code{target} commands, | |
c906108c SS |
14312 | with @code{gnutarget} the @code{target} refers to a program, not a machine. |
14313 | ||
d4f3574e | 14314 | @quotation |
c906108c SS |
14315 | @emph{Warning:} To specify a file format with @code{set gnutarget}, |
14316 | you must know the actual BFD name. | |
d4f3574e | 14317 | @end quotation |
c906108c | 14318 | |
d4f3574e | 14319 | @noindent |
79a6e687 | 14320 | @xref{Files, , Commands to Specify Files}. |
c906108c | 14321 | |
5d161b24 | 14322 | @kindex show gnutarget |
c906108c SS |
14323 | @item show gnutarget |
14324 | Use the @code{show gnutarget} command to display what file format | |
14325 | @code{gnutarget} is set to read. If you have not set @code{gnutarget}, | |
14326 | @value{GDBN} will determine the file format for each file automatically, | |
14327 | and @code{show gnutarget} displays @samp{The current BDF target is "auto"}. | |
14328 | @end table | |
14329 | ||
4644b6e3 | 14330 | @cindex common targets |
c906108c SS |
14331 | Here are some common targets (available, or not, depending on the GDB |
14332 | configuration): | |
c906108c SS |
14333 | |
14334 | @table @code | |
4644b6e3 | 14335 | @kindex target |
c906108c | 14336 | @item target exec @var{program} |
4644b6e3 | 14337 | @cindex executable file target |
c906108c SS |
14338 | An executable file. @samp{target exec @var{program}} is the same as |
14339 | @samp{exec-file @var{program}}. | |
14340 | ||
c906108c | 14341 | @item target core @var{filename} |
4644b6e3 | 14342 | @cindex core dump file target |
c906108c SS |
14343 | A core dump file. @samp{target core @var{filename}} is the same as |
14344 | @samp{core-file @var{filename}}. | |
c906108c | 14345 | |
1a10341b | 14346 | @item target remote @var{medium} |
4644b6e3 | 14347 | @cindex remote target |
1a10341b JB |
14348 | A remote system connected to @value{GDBN} via a serial line or network |
14349 | connection. This command tells @value{GDBN} to use its own remote | |
14350 | protocol over @var{medium} for debugging. @xref{Remote Debugging}. | |
14351 | ||
14352 | For example, if you have a board connected to @file{/dev/ttya} on the | |
14353 | machine running @value{GDBN}, you could say: | |
14354 | ||
14355 | @smallexample | |
14356 | target remote /dev/ttya | |
14357 | @end smallexample | |
14358 | ||
14359 | @code{target remote} supports the @code{load} command. This is only | |
14360 | useful if you have some other way of getting the stub to the target | |
14361 | system, and you can put it somewhere in memory where it won't get | |
14362 | clobbered by the download. | |
c906108c | 14363 | |
c906108c | 14364 | @item target sim |
4644b6e3 | 14365 | @cindex built-in simulator target |
2df3850c | 14366 | Builtin CPU simulator. @value{GDBN} includes simulators for most architectures. |
104c1213 | 14367 | In general, |
474c8240 | 14368 | @smallexample |
104c1213 JM |
14369 | target sim |
14370 | load | |
14371 | run | |
474c8240 | 14372 | @end smallexample |
d4f3574e | 14373 | @noindent |
104c1213 | 14374 | works; however, you cannot assume that a specific memory map, device |
d4f3574e | 14375 | drivers, or even basic I/O is available, although some simulators do |
104c1213 JM |
14376 | provide these. For info about any processor-specific simulator details, |
14377 | see the appropriate section in @ref{Embedded Processors, ,Embedded | |
14378 | Processors}. | |
14379 | ||
c906108c SS |
14380 | @end table |
14381 | ||
104c1213 | 14382 | Some configurations may include these targets as well: |
c906108c SS |
14383 | |
14384 | @table @code | |
14385 | ||
c906108c | 14386 | @item target nrom @var{dev} |
4644b6e3 | 14387 | @cindex NetROM ROM emulator target |
c906108c SS |
14388 | NetROM ROM emulator. This target only supports downloading. |
14389 | ||
c906108c SS |
14390 | @end table |
14391 | ||
5d161b24 | 14392 | Different targets are available on different configurations of @value{GDBN}; |
c906108c | 14393 | your configuration may have more or fewer targets. |
c906108c | 14394 | |
721c2651 EZ |
14395 | Many remote targets require you to download the executable's code once |
14396 | you've successfully established a connection. You may wish to control | |
3d00d119 DJ |
14397 | various aspects of this process. |
14398 | ||
14399 | @table @code | |
721c2651 EZ |
14400 | |
14401 | @item set hash | |
14402 | @kindex set hash@r{, for remote monitors} | |
14403 | @cindex hash mark while downloading | |
14404 | This command controls whether a hash mark @samp{#} is displayed while | |
14405 | downloading a file to the remote monitor. If on, a hash mark is | |
14406 | displayed after each S-record is successfully downloaded to the | |
14407 | monitor. | |
14408 | ||
14409 | @item show hash | |
14410 | @kindex show hash@r{, for remote monitors} | |
14411 | Show the current status of displaying the hash mark. | |
14412 | ||
14413 | @item set debug monitor | |
14414 | @kindex set debug monitor | |
14415 | @cindex display remote monitor communications | |
14416 | Enable or disable display of communications messages between | |
14417 | @value{GDBN} and the remote monitor. | |
14418 | ||
14419 | @item show debug monitor | |
14420 | @kindex show debug monitor | |
14421 | Show the current status of displaying communications between | |
14422 | @value{GDBN} and the remote monitor. | |
a8f24a35 | 14423 | @end table |
c906108c SS |
14424 | |
14425 | @table @code | |
14426 | ||
14427 | @kindex load @var{filename} | |
14428 | @item load @var{filename} | |
8edfe269 | 14429 | @anchor{load} |
c906108c SS |
14430 | Depending on what remote debugging facilities are configured into |
14431 | @value{GDBN}, the @code{load} command may be available. Where it exists, it | |
14432 | is meant to make @var{filename} (an executable) available for debugging | |
14433 | on the remote system---by downloading, or dynamic linking, for example. | |
14434 | @code{load} also records the @var{filename} symbol table in @value{GDBN}, like | |
14435 | the @code{add-symbol-file} command. | |
14436 | ||
14437 | If your @value{GDBN} does not have a @code{load} command, attempting to | |
14438 | execute it gets the error message ``@code{You can't do that when your | |
14439 | target is @dots{}}'' | |
c906108c SS |
14440 | |
14441 | The file is loaded at whatever address is specified in the executable. | |
14442 | For some object file formats, you can specify the load address when you | |
14443 | link the program; for other formats, like a.out, the object file format | |
14444 | specifies a fixed address. | |
14445 | @c FIXME! This would be a good place for an xref to the GNU linker doc. | |
14446 | ||
68437a39 DJ |
14447 | Depending on the remote side capabilities, @value{GDBN} may be able to |
14448 | load programs into flash memory. | |
14449 | ||
c906108c SS |
14450 | @code{load} does not repeat if you press @key{RET} again after using it. |
14451 | @end table | |
14452 | ||
6d2ebf8b | 14453 | @node Byte Order |
79a6e687 | 14454 | @section Choosing Target Byte Order |
7a292a7a | 14455 | |
c906108c SS |
14456 | @cindex choosing target byte order |
14457 | @cindex target byte order | |
c906108c | 14458 | |
172c2a43 | 14459 | Some types of processors, such as the MIPS, PowerPC, and Renesas SH, |
c906108c SS |
14460 | offer the ability to run either big-endian or little-endian byte |
14461 | orders. Usually the executable or symbol will include a bit to | |
14462 | designate the endian-ness, and you will not need to worry about | |
14463 | which to use. However, you may still find it useful to adjust | |
d4f3574e | 14464 | @value{GDBN}'s idea of processor endian-ness manually. |
c906108c SS |
14465 | |
14466 | @table @code | |
4644b6e3 | 14467 | @kindex set endian |
c906108c SS |
14468 | @item set endian big |
14469 | Instruct @value{GDBN} to assume the target is big-endian. | |
14470 | ||
c906108c SS |
14471 | @item set endian little |
14472 | Instruct @value{GDBN} to assume the target is little-endian. | |
14473 | ||
c906108c SS |
14474 | @item set endian auto |
14475 | Instruct @value{GDBN} to use the byte order associated with the | |
14476 | executable. | |
14477 | ||
14478 | @item show endian | |
14479 | Display @value{GDBN}'s current idea of the target byte order. | |
14480 | ||
14481 | @end table | |
14482 | ||
14483 | Note that these commands merely adjust interpretation of symbolic | |
14484 | data on the host, and that they have absolutely no effect on the | |
14485 | target system. | |
14486 | ||
ea35711c DJ |
14487 | |
14488 | @node Remote Debugging | |
14489 | @chapter Debugging Remote Programs | |
c906108c SS |
14490 | @cindex remote debugging |
14491 | ||
14492 | If you are trying to debug a program running on a machine that cannot run | |
5d161b24 DB |
14493 | @value{GDBN} in the usual way, it is often useful to use remote debugging. |
14494 | For example, you might use remote debugging on an operating system kernel, | |
c906108c SS |
14495 | or on a small system which does not have a general purpose operating system |
14496 | powerful enough to run a full-featured debugger. | |
14497 | ||
14498 | Some configurations of @value{GDBN} have special serial or TCP/IP interfaces | |
14499 | to make this work with particular debugging targets. In addition, | |
5d161b24 | 14500 | @value{GDBN} comes with a generic serial protocol (specific to @value{GDBN}, |
c906108c SS |
14501 | but not specific to any particular target system) which you can use if you |
14502 | write the remote stubs---the code that runs on the remote system to | |
14503 | communicate with @value{GDBN}. | |
14504 | ||
14505 | Other remote targets may be available in your | |
14506 | configuration of @value{GDBN}; use @code{help target} to list them. | |
c906108c | 14507 | |
6b2f586d | 14508 | @menu |
07f31aa6 | 14509 | * Connecting:: Connecting to a remote target |
a6b151f1 | 14510 | * File Transfer:: Sending files to a remote system |
6b2f586d | 14511 | * Server:: Using the gdbserver program |
79a6e687 BW |
14512 | * Remote Configuration:: Remote configuration |
14513 | * Remote Stub:: Implementing a remote stub | |
6b2f586d AC |
14514 | @end menu |
14515 | ||
07f31aa6 | 14516 | @node Connecting |
79a6e687 | 14517 | @section Connecting to a Remote Target |
07f31aa6 DJ |
14518 | |
14519 | On the @value{GDBN} host machine, you will need an unstripped copy of | |
d3e8051b | 14520 | your program, since @value{GDBN} needs symbol and debugging information. |
07f31aa6 DJ |
14521 | Start up @value{GDBN} as usual, using the name of the local copy of your |
14522 | program as the first argument. | |
14523 | ||
86941c27 JB |
14524 | @cindex @code{target remote} |
14525 | @value{GDBN} can communicate with the target over a serial line, or | |
14526 | over an @acronym{IP} network using @acronym{TCP} or @acronym{UDP}. In | |
14527 | each case, @value{GDBN} uses the same protocol for debugging your | |
14528 | program; only the medium carrying the debugging packets varies. The | |
14529 | @code{target remote} command establishes a connection to the target. | |
14530 | Its arguments indicate which medium to use: | |
14531 | ||
14532 | @table @code | |
14533 | ||
14534 | @item target remote @var{serial-device} | |
07f31aa6 | 14535 | @cindex serial line, @code{target remote} |
86941c27 JB |
14536 | Use @var{serial-device} to communicate with the target. For example, |
14537 | to use a serial line connected to the device named @file{/dev/ttyb}: | |
14538 | ||
14539 | @smallexample | |
14540 | target remote /dev/ttyb | |
14541 | @end smallexample | |
14542 | ||
07f31aa6 DJ |
14543 | If you're using a serial line, you may want to give @value{GDBN} the |
14544 | @w{@samp{--baud}} option, or use the @code{set remotebaud} command | |
79a6e687 | 14545 | (@pxref{Remote Configuration, set remotebaud}) before the |
9c16f35a | 14546 | @code{target} command. |
07f31aa6 | 14547 | |
86941c27 JB |
14548 | @item target remote @code{@var{host}:@var{port}} |
14549 | @itemx target remote @code{tcp:@var{host}:@var{port}} | |
14550 | @cindex @acronym{TCP} port, @code{target remote} | |
14551 | Debug using a @acronym{TCP} connection to @var{port} on @var{host}. | |
14552 | The @var{host} may be either a host name or a numeric @acronym{IP} | |
14553 | address; @var{port} must be a decimal number. The @var{host} could be | |
14554 | the target machine itself, if it is directly connected to the net, or | |
14555 | it might be a terminal server which in turn has a serial line to the | |
14556 | target. | |
07f31aa6 | 14557 | |
86941c27 JB |
14558 | For example, to connect to port 2828 on a terminal server named |
14559 | @code{manyfarms}: | |
07f31aa6 DJ |
14560 | |
14561 | @smallexample | |
14562 | target remote manyfarms:2828 | |
14563 | @end smallexample | |
14564 | ||
86941c27 JB |
14565 | If your remote target is actually running on the same machine as your |
14566 | debugger session (e.g.@: a simulator for your target running on the | |
14567 | same host), you can omit the hostname. For example, to connect to | |
14568 | port 1234 on your local machine: | |
07f31aa6 DJ |
14569 | |
14570 | @smallexample | |
14571 | target remote :1234 | |
14572 | @end smallexample | |
14573 | @noindent | |
14574 | ||
14575 | Note that the colon is still required here. | |
14576 | ||
86941c27 JB |
14577 | @item target remote @code{udp:@var{host}:@var{port}} |
14578 | @cindex @acronym{UDP} port, @code{target remote} | |
14579 | Debug using @acronym{UDP} packets to @var{port} on @var{host}. For example, to | |
14580 | connect to @acronym{UDP} port 2828 on a terminal server named @code{manyfarms}: | |
07f31aa6 DJ |
14581 | |
14582 | @smallexample | |
14583 | target remote udp:manyfarms:2828 | |
14584 | @end smallexample | |
14585 | ||
86941c27 JB |
14586 | When using a @acronym{UDP} connection for remote debugging, you should |
14587 | keep in mind that the `U' stands for ``Unreliable''. @acronym{UDP} | |
14588 | can silently drop packets on busy or unreliable networks, which will | |
14589 | cause havoc with your debugging session. | |
14590 | ||
66b8c7f6 JB |
14591 | @item target remote | @var{command} |
14592 | @cindex pipe, @code{target remote} to | |
14593 | Run @var{command} in the background and communicate with it using a | |
14594 | pipe. The @var{command} is a shell command, to be parsed and expanded | |
14595 | by the system's command shell, @code{/bin/sh}; it should expect remote | |
14596 | protocol packets on its standard input, and send replies on its | |
14597 | standard output. You could use this to run a stand-alone simulator | |
14598 | that speaks the remote debugging protocol, to make net connections | |
14599 | using programs like @code{ssh}, or for other similar tricks. | |
14600 | ||
14601 | If @var{command} closes its standard output (perhaps by exiting), | |
14602 | @value{GDBN} will try to send it a @code{SIGTERM} signal. (If the | |
14603 | program has already exited, this will have no effect.) | |
14604 | ||
86941c27 | 14605 | @end table |
07f31aa6 | 14606 | |
86941c27 | 14607 | Once the connection has been established, you can use all the usual |
8edfe269 DJ |
14608 | commands to examine and change data. The remote program is already |
14609 | running; you can use @kbd{step} and @kbd{continue}, and you do not | |
14610 | need to use @kbd{run}. | |
07f31aa6 DJ |
14611 | |
14612 | @cindex interrupting remote programs | |
14613 | @cindex remote programs, interrupting | |
14614 | Whenever @value{GDBN} is waiting for the remote program, if you type the | |
c8aa23ab | 14615 | interrupt character (often @kbd{Ctrl-c}), @value{GDBN} attempts to stop the |
07f31aa6 DJ |
14616 | program. This may or may not succeed, depending in part on the hardware |
14617 | and the serial drivers the remote system uses. If you type the | |
14618 | interrupt character once again, @value{GDBN} displays this prompt: | |
14619 | ||
14620 | @smallexample | |
14621 | Interrupted while waiting for the program. | |
14622 | Give up (and stop debugging it)? (y or n) | |
14623 | @end smallexample | |
14624 | ||
14625 | If you type @kbd{y}, @value{GDBN} abandons the remote debugging session. | |
14626 | (If you decide you want to try again later, you can use @samp{target | |
14627 | remote} again to connect once more.) If you type @kbd{n}, @value{GDBN} | |
14628 | goes back to waiting. | |
14629 | ||
14630 | @table @code | |
14631 | @kindex detach (remote) | |
14632 | @item detach | |
14633 | When you have finished debugging the remote program, you can use the | |
14634 | @code{detach} command to release it from @value{GDBN} control. | |
14635 | Detaching from the target normally resumes its execution, but the results | |
14636 | will depend on your particular remote stub. After the @code{detach} | |
14637 | command, @value{GDBN} is free to connect to another target. | |
14638 | ||
14639 | @kindex disconnect | |
14640 | @item disconnect | |
14641 | The @code{disconnect} command behaves like @code{detach}, except that | |
14642 | the target is generally not resumed. It will wait for @value{GDBN} | |
14643 | (this instance or another one) to connect and continue debugging. After | |
14644 | the @code{disconnect} command, @value{GDBN} is again free to connect to | |
14645 | another target. | |
09d4efe1 EZ |
14646 | |
14647 | @cindex send command to remote monitor | |
fad38dfa EZ |
14648 | @cindex extend @value{GDBN} for remote targets |
14649 | @cindex add new commands for external monitor | |
09d4efe1 EZ |
14650 | @kindex monitor |
14651 | @item monitor @var{cmd} | |
fad38dfa EZ |
14652 | This command allows you to send arbitrary commands directly to the |
14653 | remote monitor. Since @value{GDBN} doesn't care about the commands it | |
14654 | sends like this, this command is the way to extend @value{GDBN}---you | |
14655 | can add new commands that only the external monitor will understand | |
14656 | and implement. | |
07f31aa6 DJ |
14657 | @end table |
14658 | ||
a6b151f1 DJ |
14659 | @node File Transfer |
14660 | @section Sending files to a remote system | |
14661 | @cindex remote target, file transfer | |
14662 | @cindex file transfer | |
14663 | @cindex sending files to remote systems | |
14664 | ||
14665 | Some remote targets offer the ability to transfer files over the same | |
14666 | connection used to communicate with @value{GDBN}. This is convenient | |
14667 | for targets accessible through other means, e.g.@: @sc{gnu}/Linux systems | |
14668 | running @code{gdbserver} over a network interface. For other targets, | |
14669 | e.g.@: embedded devices with only a single serial port, this may be | |
14670 | the only way to upload or download files. | |
14671 | ||
14672 | Not all remote targets support these commands. | |
14673 | ||
14674 | @table @code | |
14675 | @kindex remote put | |
14676 | @item remote put @var{hostfile} @var{targetfile} | |
14677 | Copy file @var{hostfile} from the host system (the machine running | |
14678 | @value{GDBN}) to @var{targetfile} on the target system. | |
14679 | ||
14680 | @kindex remote get | |
14681 | @item remote get @var{targetfile} @var{hostfile} | |
14682 | Copy file @var{targetfile} from the target system to @var{hostfile} | |
14683 | on the host system. | |
14684 | ||
14685 | @kindex remote delete | |
14686 | @item remote delete @var{targetfile} | |
14687 | Delete @var{targetfile} from the target system. | |
14688 | ||
14689 | @end table | |
14690 | ||
6f05cf9f | 14691 | @node Server |
79a6e687 | 14692 | @section Using the @code{gdbserver} Program |
6f05cf9f AC |
14693 | |
14694 | @kindex gdbserver | |
14695 | @cindex remote connection without stubs | |
14696 | @code{gdbserver} is a control program for Unix-like systems, which | |
14697 | allows you to connect your program with a remote @value{GDBN} via | |
14698 | @code{target remote}---but without linking in the usual debugging stub. | |
14699 | ||
14700 | @code{gdbserver} is not a complete replacement for the debugging stubs, | |
14701 | because it requires essentially the same operating-system facilities | |
14702 | that @value{GDBN} itself does. In fact, a system that can run | |
14703 | @code{gdbserver} to connect to a remote @value{GDBN} could also run | |
14704 | @value{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless, | |
14705 | because it is a much smaller program than @value{GDBN} itself. It is | |
14706 | also easier to port than all of @value{GDBN}, so you may be able to get | |
14707 | started more quickly on a new system by using @code{gdbserver}. | |
14708 | Finally, if you develop code for real-time systems, you may find that | |
14709 | the tradeoffs involved in real-time operation make it more convenient to | |
14710 | do as much development work as possible on another system, for example | |
14711 | by cross-compiling. You can use @code{gdbserver} to make a similar | |
14712 | choice for debugging. | |
14713 | ||
14714 | @value{GDBN} and @code{gdbserver} communicate via either a serial line | |
14715 | or a TCP connection, using the standard @value{GDBN} remote serial | |
14716 | protocol. | |
14717 | ||
2d717e4f DJ |
14718 | @quotation |
14719 | @emph{Warning:} @code{gdbserver} does not have any built-in security. | |
14720 | Do not run @code{gdbserver} connected to any public network; a | |
14721 | @value{GDBN} connection to @code{gdbserver} provides access to the | |
14722 | target system with the same privileges as the user running | |
14723 | @code{gdbserver}. | |
14724 | @end quotation | |
14725 | ||
14726 | @subsection Running @code{gdbserver} | |
14727 | @cindex arguments, to @code{gdbserver} | |
14728 | ||
14729 | Run @code{gdbserver} on the target system. You need a copy of the | |
14730 | program you want to debug, including any libraries it requires. | |
6f05cf9f AC |
14731 | @code{gdbserver} does not need your program's symbol table, so you can |
14732 | strip the program if necessary to save space. @value{GDBN} on the host | |
14733 | system does all the symbol handling. | |
14734 | ||
14735 | To use the server, you must tell it how to communicate with @value{GDBN}; | |
56460a61 | 14736 | the name of your program; and the arguments for your program. The usual |
6f05cf9f AC |
14737 | syntax is: |
14738 | ||
14739 | @smallexample | |
14740 | target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ] | |
14741 | @end smallexample | |
14742 | ||
14743 | @var{comm} is either a device name (to use a serial line) or a TCP | |
14744 | hostname and portnumber. For example, to debug Emacs with the argument | |
14745 | @samp{foo.txt} and communicate with @value{GDBN} over the serial port | |
14746 | @file{/dev/com1}: | |
14747 | ||
14748 | @smallexample | |
14749 | target> gdbserver /dev/com1 emacs foo.txt | |
14750 | @end smallexample | |
14751 | ||
14752 | @code{gdbserver} waits passively for the host @value{GDBN} to communicate | |
14753 | with it. | |
14754 | ||
14755 | To use a TCP connection instead of a serial line: | |
14756 | ||
14757 | @smallexample | |
14758 | target> gdbserver host:2345 emacs foo.txt | |
14759 | @end smallexample | |
14760 | ||
14761 | The only difference from the previous example is the first argument, | |
14762 | specifying that you are communicating with the host @value{GDBN} via | |
14763 | TCP. The @samp{host:2345} argument means that @code{gdbserver} is to | |
14764 | expect a TCP connection from machine @samp{host} to local TCP port 2345. | |
14765 | (Currently, the @samp{host} part is ignored.) You can choose any number | |
14766 | you want for the port number as long as it does not conflict with any | |
14767 | TCP ports already in use on the target system (for example, @code{23} is | |
14768 | reserved for @code{telnet}).@footnote{If you choose a port number that | |
14769 | conflicts with another service, @code{gdbserver} prints an error message | |
14770 | and exits.} You must use the same port number with the host @value{GDBN} | |
14771 | @code{target remote} command. | |
14772 | ||
2d717e4f DJ |
14773 | @subsubsection Attaching to a Running Program |
14774 | ||
56460a61 DJ |
14775 | On some targets, @code{gdbserver} can also attach to running programs. |
14776 | This is accomplished via the @code{--attach} argument. The syntax is: | |
14777 | ||
14778 | @smallexample | |
2d717e4f | 14779 | target> gdbserver --attach @var{comm} @var{pid} |
56460a61 DJ |
14780 | @end smallexample |
14781 | ||
14782 | @var{pid} is the process ID of a currently running process. It isn't necessary | |
14783 | to point @code{gdbserver} at a binary for the running process. | |
14784 | ||
b1fe9455 DJ |
14785 | @pindex pidof |
14786 | @cindex attach to a program by name | |
14787 | You can debug processes by name instead of process ID if your target has the | |
14788 | @code{pidof} utility: | |
14789 | ||
14790 | @smallexample | |
2d717e4f | 14791 | target> gdbserver --attach @var{comm} `pidof @var{program}` |
b1fe9455 DJ |
14792 | @end smallexample |
14793 | ||
f822c95b | 14794 | In case more than one copy of @var{program} is running, or @var{program} |
b1fe9455 DJ |
14795 | has multiple threads, most versions of @code{pidof} support the |
14796 | @code{-s} option to only return the first process ID. | |
14797 | ||
2d717e4f DJ |
14798 | @subsubsection Multi-Process Mode for @code{gdbserver} |
14799 | @cindex gdbserver, multiple processes | |
14800 | @cindex multiple processes with gdbserver | |
14801 | ||
14802 | When you connect to @code{gdbserver} using @code{target remote}, | |
14803 | @code{gdbserver} debugs the specified program only once. When the | |
14804 | program exits, or you detach from it, @value{GDBN} closes the connection | |
14805 | and @code{gdbserver} exits. | |
14806 | ||
6e6c6f50 | 14807 | If you connect using @kbd{target extended-remote}, @code{gdbserver} |
2d717e4f DJ |
14808 | enters multi-process mode. When the debugged program exits, or you |
14809 | detach from it, @value{GDBN} stays connected to @code{gdbserver} even | |
14810 | though no program is running. The @code{run} and @code{attach} | |
14811 | commands instruct @code{gdbserver} to run or attach to a new program. | |
14812 | The @code{run} command uses @code{set remote exec-file} (@pxref{set | |
14813 | remote exec-file}) to select the program to run. Command line | |
14814 | arguments are supported, except for wildcard expansion and I/O | |
14815 | redirection (@pxref{Arguments}). | |
14816 | ||
14817 | To start @code{gdbserver} without supplying an initial command to run | |
14818 | or process ID to attach, use the @option{--multi} command line option. | |
6e6c6f50 | 14819 | Then you can connect using @kbd{target extended-remote} and start |
2d717e4f DJ |
14820 | the program you want to debug. |
14821 | ||
14822 | @code{gdbserver} does not automatically exit in multi-process mode. | |
14823 | You can terminate it by using @code{monitor exit} | |
14824 | (@pxref{Monitor Commands for gdbserver}). | |
14825 | ||
14826 | @subsubsection Other Command-Line Arguments for @code{gdbserver} | |
14827 | ||
62709adf PA |
14828 | The @option{--debug} option tells @code{gdbserver} to display extra |
14829 | status information about the debugging process. The | |
14830 | @option{--remote-debug} option tells @code{gdbserver} to display | |
14831 | remote protocol debug output. These options are intended for | |
14832 | @code{gdbserver} development and for bug reports to the developers. | |
2d717e4f | 14833 | |
ccd213ac DJ |
14834 | The @option{--wrapper} option specifies a wrapper to launch programs |
14835 | for debugging. The option should be followed by the name of the | |
14836 | wrapper, then any command-line arguments to pass to the wrapper, then | |
14837 | @kbd{--} indicating the end of the wrapper arguments. | |
14838 | ||
14839 | @code{gdbserver} runs the specified wrapper program with a combined | |
14840 | command line including the wrapper arguments, then the name of the | |
14841 | program to debug, then any arguments to the program. The wrapper | |
14842 | runs until it executes your program, and then @value{GDBN} gains control. | |
14843 | ||
14844 | You can use any program that eventually calls @code{execve} with | |
14845 | its arguments as a wrapper. Several standard Unix utilities do | |
14846 | this, e.g.@: @code{env} and @code{nohup}. Any Unix shell script ending | |
14847 | with @code{exec "$@@"} will also work. | |
14848 | ||
14849 | For example, you can use @code{env} to pass an environment variable to | |
14850 | the debugged program, without setting the variable in @code{gdbserver}'s | |
14851 | environment: | |
14852 | ||
14853 | @smallexample | |
14854 | $ gdbserver --wrapper env LD_PRELOAD=libtest.so -- :2222 ./testprog | |
14855 | @end smallexample | |
14856 | ||
2d717e4f DJ |
14857 | @subsection Connecting to @code{gdbserver} |
14858 | ||
14859 | Run @value{GDBN} on the host system. | |
14860 | ||
14861 | First make sure you have the necessary symbol files. Load symbols for | |
f822c95b DJ |
14862 | your application using the @code{file} command before you connect. Use |
14863 | @code{set sysroot} to locate target libraries (unless your @value{GDBN} | |
2d717e4f | 14864 | was compiled with the correct sysroot using @code{--with-sysroot}). |
f822c95b DJ |
14865 | |
14866 | The symbol file and target libraries must exactly match the executable | |
14867 | and libraries on the target, with one exception: the files on the host | |
14868 | system should not be stripped, even if the files on the target system | |
14869 | are. Mismatched or missing files will lead to confusing results | |
14870 | during debugging. On @sc{gnu}/Linux targets, mismatched or missing | |
14871 | files may also prevent @code{gdbserver} from debugging multi-threaded | |
14872 | programs. | |
14873 | ||
79a6e687 | 14874 | Connect to your target (@pxref{Connecting,,Connecting to a Remote Target}). |
6f05cf9f AC |
14875 | For TCP connections, you must start up @code{gdbserver} prior to using |
14876 | the @code{target remote} command. Otherwise you may get an error whose | |
14877 | text depends on the host system, but which usually looks something like | |
2d717e4f | 14878 | @samp{Connection refused}. Don't use the @code{load} |
397ca115 | 14879 | command in @value{GDBN} when using @code{gdbserver}, since the program is |
f822c95b | 14880 | already on the target. |
07f31aa6 | 14881 | |
79a6e687 | 14882 | @subsection Monitor Commands for @code{gdbserver} |
c74d0ad8 | 14883 | @cindex monitor commands, for @code{gdbserver} |
2d717e4f | 14884 | @anchor{Monitor Commands for gdbserver} |
c74d0ad8 DJ |
14885 | |
14886 | During a @value{GDBN} session using @code{gdbserver}, you can use the | |
14887 | @code{monitor} command to send special requests to @code{gdbserver}. | |
2d717e4f | 14888 | Here are the available commands. |
c74d0ad8 DJ |
14889 | |
14890 | @table @code | |
14891 | @item monitor help | |
14892 | List the available monitor commands. | |
14893 | ||
14894 | @item monitor set debug 0 | |
14895 | @itemx monitor set debug 1 | |
14896 | Disable or enable general debugging messages. | |
14897 | ||
14898 | @item monitor set remote-debug 0 | |
14899 | @itemx monitor set remote-debug 1 | |
14900 | Disable or enable specific debugging messages associated with the remote | |
14901 | protocol (@pxref{Remote Protocol}). | |
14902 | ||
2d717e4f DJ |
14903 | @item monitor exit |
14904 | Tell gdbserver to exit immediately. This command should be followed by | |
14905 | @code{disconnect} to close the debugging session. @code{gdbserver} will | |
14906 | detach from any attached processes and kill any processes it created. | |
14907 | Use @code{monitor exit} to terminate @code{gdbserver} at the end | |
14908 | of a multi-process mode debug session. | |
14909 | ||
c74d0ad8 DJ |
14910 | @end table |
14911 | ||
79a6e687 BW |
14912 | @node Remote Configuration |
14913 | @section Remote Configuration | |
501eef12 | 14914 | |
9c16f35a EZ |
14915 | @kindex set remote |
14916 | @kindex show remote | |
14917 | This section documents the configuration options available when | |
14918 | debugging remote programs. For the options related to the File I/O | |
fc320d37 | 14919 | extensions of the remote protocol, see @ref{system, |
9c16f35a | 14920 | system-call-allowed}. |
501eef12 AC |
14921 | |
14922 | @table @code | |
9c16f35a | 14923 | @item set remoteaddresssize @var{bits} |
d3e8051b | 14924 | @cindex address size for remote targets |
9c16f35a EZ |
14925 | @cindex bits in remote address |
14926 | Set the maximum size of address in a memory packet to the specified | |
14927 | number of bits. @value{GDBN} will mask off the address bits above | |
14928 | that number, when it passes addresses to the remote target. The | |
14929 | default value is the number of bits in the target's address. | |
14930 | ||
14931 | @item show remoteaddresssize | |
14932 | Show the current value of remote address size in bits. | |
14933 | ||
14934 | @item set remotebaud @var{n} | |
14935 | @cindex baud rate for remote targets | |
14936 | Set the baud rate for the remote serial I/O to @var{n} baud. The | |
14937 | value is used to set the speed of the serial port used for debugging | |
14938 | remote targets. | |
14939 | ||
14940 | @item show remotebaud | |
14941 | Show the current speed of the remote connection. | |
14942 | ||
14943 | @item set remotebreak | |
14944 | @cindex interrupt remote programs | |
14945 | @cindex BREAK signal instead of Ctrl-C | |
9a6253be | 14946 | @anchor{set remotebreak} |
9c16f35a | 14947 | If set to on, @value{GDBN} sends a @code{BREAK} signal to the remote |
c8aa23ab | 14948 | when you type @kbd{Ctrl-c} to interrupt the program running |
9a7a1b36 | 14949 | on the remote. If set to off, @value{GDBN} sends the @samp{Ctrl-C} |
9c16f35a EZ |
14950 | character instead. The default is off, since most remote systems |
14951 | expect to see @samp{Ctrl-C} as the interrupt signal. | |
14952 | ||
14953 | @item show remotebreak | |
14954 | Show whether @value{GDBN} sends @code{BREAK} or @samp{Ctrl-C} to | |
14955 | interrupt the remote program. | |
14956 | ||
23776285 MR |
14957 | @item set remoteflow on |
14958 | @itemx set remoteflow off | |
14959 | @kindex set remoteflow | |
14960 | Enable or disable hardware flow control (@code{RTS}/@code{CTS}) | |
14961 | on the serial port used to communicate to the remote target. | |
14962 | ||
14963 | @item show remoteflow | |
14964 | @kindex show remoteflow | |
14965 | Show the current setting of hardware flow control. | |
14966 | ||
9c16f35a EZ |
14967 | @item set remotelogbase @var{base} |
14968 | Set the base (a.k.a.@: radix) of logging serial protocol | |
14969 | communications to @var{base}. Supported values of @var{base} are: | |
14970 | @code{ascii}, @code{octal}, and @code{hex}. The default is | |
14971 | @code{ascii}. | |
14972 | ||
14973 | @item show remotelogbase | |
14974 | Show the current setting of the radix for logging remote serial | |
14975 | protocol. | |
14976 | ||
14977 | @item set remotelogfile @var{file} | |
14978 | @cindex record serial communications on file | |
14979 | Record remote serial communications on the named @var{file}. The | |
14980 | default is not to record at all. | |
14981 | ||
14982 | @item show remotelogfile. | |
14983 | Show the current setting of the file name on which to record the | |
14984 | serial communications. | |
14985 | ||
14986 | @item set remotetimeout @var{num} | |
14987 | @cindex timeout for serial communications | |
14988 | @cindex remote timeout | |
14989 | Set the timeout limit to wait for the remote target to respond to | |
14990 | @var{num} seconds. The default is 2 seconds. | |
14991 | ||
14992 | @item show remotetimeout | |
14993 | Show the current number of seconds to wait for the remote target | |
14994 | responses. | |
14995 | ||
14996 | @cindex limit hardware breakpoints and watchpoints | |
14997 | @cindex remote target, limit break- and watchpoints | |
501eef12 AC |
14998 | @anchor{set remote hardware-watchpoint-limit} |
14999 | @anchor{set remote hardware-breakpoint-limit} | |
15000 | @item set remote hardware-watchpoint-limit @var{limit} | |
15001 | @itemx set remote hardware-breakpoint-limit @var{limit} | |
15002 | Restrict @value{GDBN} to using @var{limit} remote hardware breakpoint or | |
15003 | watchpoints. A limit of -1, the default, is treated as unlimited. | |
2d717e4f DJ |
15004 | |
15005 | @item set remote exec-file @var{filename} | |
15006 | @itemx show remote exec-file | |
15007 | @anchor{set remote exec-file} | |
15008 | @cindex executable file, for remote target | |
15009 | Select the file used for @code{run} with @code{target | |
15010 | extended-remote}. This should be set to a filename valid on the | |
15011 | target system. If it is not set, the target will use a default | |
15012 | filename (e.g.@: the last program run). | |
84603566 SL |
15013 | |
15014 | @kindex set tcp | |
15015 | @kindex show tcp | |
15016 | @item set tcp auto-retry on | |
15017 | @cindex auto-retry, for remote TCP target | |
15018 | Enable auto-retry for remote TCP connections. This is useful if the remote | |
15019 | debugging agent is launched in parallel with @value{GDBN}; there is a race | |
15020 | condition because the agent may not become ready to accept the connection | |
15021 | before @value{GDBN} attempts to connect. When auto-retry is | |
15022 | enabled, if the initial attempt to connect fails, @value{GDBN} reattempts | |
15023 | to establish the connection using the timeout specified by | |
15024 | @code{set tcp connect-timeout}. | |
15025 | ||
15026 | @item set tcp auto-retry off | |
15027 | Do not auto-retry failed TCP connections. | |
15028 | ||
15029 | @item show tcp auto-retry | |
15030 | Show the current auto-retry setting. | |
15031 | ||
15032 | @item set tcp connect-timeout @var{seconds} | |
15033 | @cindex connection timeout, for remote TCP target | |
15034 | @cindex timeout, for remote target connection | |
15035 | Set the timeout for establishing a TCP connection to the remote target to | |
15036 | @var{seconds}. The timeout affects both polling to retry failed connections | |
15037 | (enabled by @code{set tcp auto-retry on}) and waiting for connections | |
15038 | that are merely slow to complete, and represents an approximate cumulative | |
15039 | value. | |
15040 | ||
15041 | @item show tcp connect-timeout | |
15042 | Show the current connection timeout setting. | |
501eef12 AC |
15043 | @end table |
15044 | ||
427c3a89 DJ |
15045 | @cindex remote packets, enabling and disabling |
15046 | The @value{GDBN} remote protocol autodetects the packets supported by | |
15047 | your debugging stub. If you need to override the autodetection, you | |
15048 | can use these commands to enable or disable individual packets. Each | |
15049 | packet can be set to @samp{on} (the remote target supports this | |
15050 | packet), @samp{off} (the remote target does not support this packet), | |
15051 | or @samp{auto} (detect remote target support for this packet). They | |
15052 | all default to @samp{auto}. For more information about each packet, | |
15053 | see @ref{Remote Protocol}. | |
15054 | ||
15055 | During normal use, you should not have to use any of these commands. | |
15056 | If you do, that may be a bug in your remote debugging stub, or a bug | |
15057 | in @value{GDBN}. You may want to report the problem to the | |
15058 | @value{GDBN} developers. | |
15059 | ||
cfa9d6d9 DJ |
15060 | For each packet @var{name}, the command to enable or disable the |
15061 | packet is @code{set remote @var{name}-packet}. The available settings | |
15062 | are: | |
427c3a89 | 15063 | |
cfa9d6d9 | 15064 | @multitable @columnfractions 0.28 0.32 0.25 |
427c3a89 DJ |
15065 | @item Command Name |
15066 | @tab Remote Packet | |
15067 | @tab Related Features | |
15068 | ||
cfa9d6d9 | 15069 | @item @code{fetch-register} |
427c3a89 DJ |
15070 | @tab @code{p} |
15071 | @tab @code{info registers} | |
15072 | ||
cfa9d6d9 | 15073 | @item @code{set-register} |
427c3a89 DJ |
15074 | @tab @code{P} |
15075 | @tab @code{set} | |
15076 | ||
cfa9d6d9 | 15077 | @item @code{binary-download} |
427c3a89 DJ |
15078 | @tab @code{X} |
15079 | @tab @code{load}, @code{set} | |
15080 | ||
cfa9d6d9 | 15081 | @item @code{read-aux-vector} |
427c3a89 DJ |
15082 | @tab @code{qXfer:auxv:read} |
15083 | @tab @code{info auxv} | |
15084 | ||
cfa9d6d9 | 15085 | @item @code{symbol-lookup} |
427c3a89 DJ |
15086 | @tab @code{qSymbol} |
15087 | @tab Detecting multiple threads | |
15088 | ||
2d717e4f DJ |
15089 | @item @code{attach} |
15090 | @tab @code{vAttach} | |
15091 | @tab @code{attach} | |
15092 | ||
cfa9d6d9 | 15093 | @item @code{verbose-resume} |
427c3a89 DJ |
15094 | @tab @code{vCont} |
15095 | @tab Stepping or resuming multiple threads | |
15096 | ||
2d717e4f DJ |
15097 | @item @code{run} |
15098 | @tab @code{vRun} | |
15099 | @tab @code{run} | |
15100 | ||
cfa9d6d9 | 15101 | @item @code{software-breakpoint} |
427c3a89 DJ |
15102 | @tab @code{Z0} |
15103 | @tab @code{break} | |
15104 | ||
cfa9d6d9 | 15105 | @item @code{hardware-breakpoint} |
427c3a89 DJ |
15106 | @tab @code{Z1} |
15107 | @tab @code{hbreak} | |
15108 | ||
cfa9d6d9 | 15109 | @item @code{write-watchpoint} |
427c3a89 DJ |
15110 | @tab @code{Z2} |
15111 | @tab @code{watch} | |
15112 | ||
cfa9d6d9 | 15113 | @item @code{read-watchpoint} |
427c3a89 DJ |
15114 | @tab @code{Z3} |
15115 | @tab @code{rwatch} | |
15116 | ||
cfa9d6d9 | 15117 | @item @code{access-watchpoint} |
427c3a89 DJ |
15118 | @tab @code{Z4} |
15119 | @tab @code{awatch} | |
15120 | ||
cfa9d6d9 DJ |
15121 | @item @code{target-features} |
15122 | @tab @code{qXfer:features:read} | |
15123 | @tab @code{set architecture} | |
15124 | ||
15125 | @item @code{library-info} | |
15126 | @tab @code{qXfer:libraries:read} | |
15127 | @tab @code{info sharedlibrary} | |
15128 | ||
15129 | @item @code{memory-map} | |
15130 | @tab @code{qXfer:memory-map:read} | |
15131 | @tab @code{info mem} | |
15132 | ||
15133 | @item @code{read-spu-object} | |
15134 | @tab @code{qXfer:spu:read} | |
15135 | @tab @code{info spu} | |
15136 | ||
15137 | @item @code{write-spu-object} | |
15138 | @tab @code{qXfer:spu:write} | |
15139 | @tab @code{info spu} | |
15140 | ||
4aa995e1 PA |
15141 | @item @code{read-siginfo-object} |
15142 | @tab @code{qXfer:siginfo:read} | |
15143 | @tab @code{print $_siginfo} | |
15144 | ||
15145 | @item @code{write-siginfo-object} | |
15146 | @tab @code{qXfer:siginfo:write} | |
15147 | @tab @code{set $_siginfo} | |
15148 | ||
cfa9d6d9 | 15149 | @item @code{get-thread-local-@*storage-address} |
427c3a89 DJ |
15150 | @tab @code{qGetTLSAddr} |
15151 | @tab Displaying @code{__thread} variables | |
15152 | ||
08388c79 DE |
15153 | @item @code{search-memory} |
15154 | @tab @code{qSearch:memory} | |
15155 | @tab @code{find} | |
15156 | ||
427c3a89 DJ |
15157 | @item @code{supported-packets} |
15158 | @tab @code{qSupported} | |
15159 | @tab Remote communications parameters | |
15160 | ||
cfa9d6d9 | 15161 | @item @code{pass-signals} |
89be2091 DJ |
15162 | @tab @code{QPassSignals} |
15163 | @tab @code{handle @var{signal}} | |
15164 | ||
a6b151f1 DJ |
15165 | @item @code{hostio-close-packet} |
15166 | @tab @code{vFile:close} | |
15167 | @tab @code{remote get}, @code{remote put} | |
15168 | ||
15169 | @item @code{hostio-open-packet} | |
15170 | @tab @code{vFile:open} | |
15171 | @tab @code{remote get}, @code{remote put} | |
15172 | ||
15173 | @item @code{hostio-pread-packet} | |
15174 | @tab @code{vFile:pread} | |
15175 | @tab @code{remote get}, @code{remote put} | |
15176 | ||
15177 | @item @code{hostio-pwrite-packet} | |
15178 | @tab @code{vFile:pwrite} | |
15179 | @tab @code{remote get}, @code{remote put} | |
15180 | ||
15181 | @item @code{hostio-unlink-packet} | |
15182 | @tab @code{vFile:unlink} | |
15183 | @tab @code{remote delete} | |
a6f3e723 SL |
15184 | |
15185 | @item @code{noack-packet} | |
15186 | @tab @code{QStartNoAckMode} | |
15187 | @tab Packet acknowledgment | |
07e059b5 VP |
15188 | |
15189 | @item @code{osdata} | |
15190 | @tab @code{qXfer:osdata:read} | |
15191 | @tab @code{info os} | |
0b16c5cf PA |
15192 | |
15193 | @item @code{query-attached} | |
15194 | @tab @code{qAttached} | |
15195 | @tab Querying remote process attach state. | |
427c3a89 DJ |
15196 | @end multitable |
15197 | ||
79a6e687 BW |
15198 | @node Remote Stub |
15199 | @section Implementing a Remote Stub | |
7a292a7a | 15200 | |
8e04817f AC |
15201 | @cindex debugging stub, example |
15202 | @cindex remote stub, example | |
15203 | @cindex stub example, remote debugging | |
15204 | The stub files provided with @value{GDBN} implement the target side of the | |
15205 | communication protocol, and the @value{GDBN} side is implemented in the | |
15206 | @value{GDBN} source file @file{remote.c}. Normally, you can simply allow | |
15207 | these subroutines to communicate, and ignore the details. (If you're | |
15208 | implementing your own stub file, you can still ignore the details: start | |
15209 | with one of the existing stub files. @file{sparc-stub.c} is the best | |
15210 | organized, and therefore the easiest to read.) | |
15211 | ||
104c1213 JM |
15212 | @cindex remote serial debugging, overview |
15213 | To debug a program running on another machine (the debugging | |
15214 | @dfn{target} machine), you must first arrange for all the usual | |
15215 | prerequisites for the program to run by itself. For example, for a C | |
15216 | program, you need: | |
c906108c | 15217 | |
104c1213 JM |
15218 | @enumerate |
15219 | @item | |
15220 | A startup routine to set up the C runtime environment; these usually | |
15221 | have a name like @file{crt0}. The startup routine may be supplied by | |
15222 | your hardware supplier, or you may have to write your own. | |
96baa820 | 15223 | |
5d161b24 | 15224 | @item |
d4f3574e | 15225 | A C subroutine library to support your program's |
104c1213 | 15226 | subroutine calls, notably managing input and output. |
96baa820 | 15227 | |
104c1213 JM |
15228 | @item |
15229 | A way of getting your program to the other machine---for example, a | |
15230 | download program. These are often supplied by the hardware | |
15231 | manufacturer, but you may have to write your own from hardware | |
15232 | documentation. | |
15233 | @end enumerate | |
96baa820 | 15234 | |
104c1213 JM |
15235 | The next step is to arrange for your program to use a serial port to |
15236 | communicate with the machine where @value{GDBN} is running (the @dfn{host} | |
15237 | machine). In general terms, the scheme looks like this: | |
96baa820 | 15238 | |
104c1213 JM |
15239 | @table @emph |
15240 | @item On the host, | |
15241 | @value{GDBN} already understands how to use this protocol; when everything | |
15242 | else is set up, you can simply use the @samp{target remote} command | |
15243 | (@pxref{Targets,,Specifying a Debugging Target}). | |
15244 | ||
15245 | @item On the target, | |
15246 | you must link with your program a few special-purpose subroutines that | |
15247 | implement the @value{GDBN} remote serial protocol. The file containing these | |
15248 | subroutines is called a @dfn{debugging stub}. | |
15249 | ||
15250 | On certain remote targets, you can use an auxiliary program | |
15251 | @code{gdbserver} instead of linking a stub into your program. | |
79a6e687 | 15252 | @xref{Server,,Using the @code{gdbserver} Program}, for details. |
104c1213 | 15253 | @end table |
96baa820 | 15254 | |
104c1213 JM |
15255 | The debugging stub is specific to the architecture of the remote |
15256 | machine; for example, use @file{sparc-stub.c} to debug programs on | |
15257 | @sc{sparc} boards. | |
96baa820 | 15258 | |
104c1213 JM |
15259 | @cindex remote serial stub list |
15260 | These working remote stubs are distributed with @value{GDBN}: | |
96baa820 | 15261 | |
104c1213 JM |
15262 | @table @code |
15263 | ||
15264 | @item i386-stub.c | |
41afff9a | 15265 | @cindex @file{i386-stub.c} |
104c1213 JM |
15266 | @cindex Intel |
15267 | @cindex i386 | |
15268 | For Intel 386 and compatible architectures. | |
15269 | ||
15270 | @item m68k-stub.c | |
41afff9a | 15271 | @cindex @file{m68k-stub.c} |
104c1213 JM |
15272 | @cindex Motorola 680x0 |
15273 | @cindex m680x0 | |
15274 | For Motorola 680x0 architectures. | |
15275 | ||
15276 | @item sh-stub.c | |
41afff9a | 15277 | @cindex @file{sh-stub.c} |
172c2a43 | 15278 | @cindex Renesas |
104c1213 | 15279 | @cindex SH |
172c2a43 | 15280 | For Renesas SH architectures. |
104c1213 JM |
15281 | |
15282 | @item sparc-stub.c | |
41afff9a | 15283 | @cindex @file{sparc-stub.c} |
104c1213 JM |
15284 | @cindex Sparc |
15285 | For @sc{sparc} architectures. | |
15286 | ||
15287 | @item sparcl-stub.c | |
41afff9a | 15288 | @cindex @file{sparcl-stub.c} |
104c1213 JM |
15289 | @cindex Fujitsu |
15290 | @cindex SparcLite | |
15291 | For Fujitsu @sc{sparclite} architectures. | |
15292 | ||
15293 | @end table | |
15294 | ||
15295 | The @file{README} file in the @value{GDBN} distribution may list other | |
15296 | recently added stubs. | |
15297 | ||
15298 | @menu | |
15299 | * Stub Contents:: What the stub can do for you | |
15300 | * Bootstrapping:: What you must do for the stub | |
15301 | * Debug Session:: Putting it all together | |
104c1213 JM |
15302 | @end menu |
15303 | ||
6d2ebf8b | 15304 | @node Stub Contents |
79a6e687 | 15305 | @subsection What the Stub Can Do for You |
104c1213 JM |
15306 | |
15307 | @cindex remote serial stub | |
15308 | The debugging stub for your architecture supplies these three | |
15309 | subroutines: | |
15310 | ||
15311 | @table @code | |
15312 | @item set_debug_traps | |
4644b6e3 | 15313 | @findex set_debug_traps |
104c1213 JM |
15314 | @cindex remote serial stub, initialization |
15315 | This routine arranges for @code{handle_exception} to run when your | |
15316 | program stops. You must call this subroutine explicitly near the | |
15317 | beginning of your program. | |
15318 | ||
15319 | @item handle_exception | |
4644b6e3 | 15320 | @findex handle_exception |
104c1213 JM |
15321 | @cindex remote serial stub, main routine |
15322 | This is the central workhorse, but your program never calls it | |
15323 | explicitly---the setup code arranges for @code{handle_exception} to | |
15324 | run when a trap is triggered. | |
15325 | ||
15326 | @code{handle_exception} takes control when your program stops during | |
15327 | execution (for example, on a breakpoint), and mediates communications | |
15328 | with @value{GDBN} on the host machine. This is where the communications | |
15329 | protocol is implemented; @code{handle_exception} acts as the @value{GDBN} | |
d4f3574e | 15330 | representative on the target machine. It begins by sending summary |
104c1213 JM |
15331 | information on the state of your program, then continues to execute, |
15332 | retrieving and transmitting any information @value{GDBN} needs, until you | |
15333 | execute a @value{GDBN} command that makes your program resume; at that point, | |
15334 | @code{handle_exception} returns control to your own code on the target | |
5d161b24 | 15335 | machine. |
104c1213 JM |
15336 | |
15337 | @item breakpoint | |
15338 | @cindex @code{breakpoint} subroutine, remote | |
15339 | Use this auxiliary subroutine to make your program contain a | |
15340 | breakpoint. Depending on the particular situation, this may be the only | |
15341 | way for @value{GDBN} to get control. For instance, if your target | |
15342 | machine has some sort of interrupt button, you won't need to call this; | |
15343 | pressing the interrupt button transfers control to | |
15344 | @code{handle_exception}---in effect, to @value{GDBN}. On some machines, | |
15345 | simply receiving characters on the serial port may also trigger a trap; | |
15346 | again, in that situation, you don't need to call @code{breakpoint} from | |
15347 | your own program---simply running @samp{target remote} from the host | |
5d161b24 | 15348 | @value{GDBN} session gets control. |
104c1213 JM |
15349 | |
15350 | Call @code{breakpoint} if none of these is true, or if you simply want | |
15351 | to make certain your program stops at a predetermined point for the | |
15352 | start of your debugging session. | |
15353 | @end table | |
15354 | ||
6d2ebf8b | 15355 | @node Bootstrapping |
79a6e687 | 15356 | @subsection What You Must Do for the Stub |
104c1213 JM |
15357 | |
15358 | @cindex remote stub, support routines | |
15359 | The debugging stubs that come with @value{GDBN} are set up for a particular | |
15360 | chip architecture, but they have no information about the rest of your | |
15361 | debugging target machine. | |
15362 | ||
15363 | First of all you need to tell the stub how to communicate with the | |
15364 | serial port. | |
15365 | ||
15366 | @table @code | |
15367 | @item int getDebugChar() | |
4644b6e3 | 15368 | @findex getDebugChar |
104c1213 JM |
15369 | Write this subroutine to read a single character from the serial port. |
15370 | It may be identical to @code{getchar} for your target system; a | |
15371 | different name is used to allow you to distinguish the two if you wish. | |
15372 | ||
15373 | @item void putDebugChar(int) | |
4644b6e3 | 15374 | @findex putDebugChar |
104c1213 | 15375 | Write this subroutine to write a single character to the serial port. |
5d161b24 | 15376 | It may be identical to @code{putchar} for your target system; a |
104c1213 JM |
15377 | different name is used to allow you to distinguish the two if you wish. |
15378 | @end table | |
15379 | ||
15380 | @cindex control C, and remote debugging | |
15381 | @cindex interrupting remote targets | |
15382 | If you want @value{GDBN} to be able to stop your program while it is | |
15383 | running, you need to use an interrupt-driven serial driver, and arrange | |
15384 | for it to stop when it receives a @code{^C} (@samp{\003}, the control-C | |
15385 | character). That is the character which @value{GDBN} uses to tell the | |
15386 | remote system to stop. | |
15387 | ||
15388 | Getting the debugging target to return the proper status to @value{GDBN} | |
15389 | probably requires changes to the standard stub; one quick and dirty way | |
15390 | is to just execute a breakpoint instruction (the ``dirty'' part is that | |
15391 | @value{GDBN} reports a @code{SIGTRAP} instead of a @code{SIGINT}). | |
15392 | ||
15393 | Other routines you need to supply are: | |
15394 | ||
15395 | @table @code | |
15396 | @item void exceptionHandler (int @var{exception_number}, void *@var{exception_address}) | |
4644b6e3 | 15397 | @findex exceptionHandler |
104c1213 JM |
15398 | Write this function to install @var{exception_address} in the exception |
15399 | handling tables. You need to do this because the stub does not have any | |
15400 | way of knowing what the exception handling tables on your target system | |
15401 | are like (for example, the processor's table might be in @sc{rom}, | |
15402 | containing entries which point to a table in @sc{ram}). | |
15403 | @var{exception_number} is the exception number which should be changed; | |
15404 | its meaning is architecture-dependent (for example, different numbers | |
15405 | might represent divide by zero, misaligned access, etc). When this | |
15406 | exception occurs, control should be transferred directly to | |
15407 | @var{exception_address}, and the processor state (stack, registers, | |
15408 | and so on) should be just as it is when a processor exception occurs. So if | |
15409 | you want to use a jump instruction to reach @var{exception_address}, it | |
15410 | should be a simple jump, not a jump to subroutine. | |
15411 | ||
15412 | For the 386, @var{exception_address} should be installed as an interrupt | |
15413 | gate so that interrupts are masked while the handler runs. The gate | |
15414 | should be at privilege level 0 (the most privileged level). The | |
15415 | @sc{sparc} and 68k stubs are able to mask interrupts themselves without | |
15416 | help from @code{exceptionHandler}. | |
15417 | ||
15418 | @item void flush_i_cache() | |
4644b6e3 | 15419 | @findex flush_i_cache |
d4f3574e | 15420 | On @sc{sparc} and @sc{sparclite} only, write this subroutine to flush the |
104c1213 JM |
15421 | instruction cache, if any, on your target machine. If there is no |
15422 | instruction cache, this subroutine may be a no-op. | |
15423 | ||
15424 | On target machines that have instruction caches, @value{GDBN} requires this | |
15425 | function to make certain that the state of your program is stable. | |
15426 | @end table | |
15427 | ||
15428 | @noindent | |
15429 | You must also make sure this library routine is available: | |
15430 | ||
15431 | @table @code | |
15432 | @item void *memset(void *, int, int) | |
4644b6e3 | 15433 | @findex memset |
104c1213 JM |
15434 | This is the standard library function @code{memset} that sets an area of |
15435 | memory to a known value. If you have one of the free versions of | |
15436 | @code{libc.a}, @code{memset} can be found there; otherwise, you must | |
15437 | either obtain it from your hardware manufacturer, or write your own. | |
15438 | @end table | |
15439 | ||
15440 | If you do not use the GNU C compiler, you may need other standard | |
15441 | library subroutines as well; this varies from one stub to another, | |
15442 | but in general the stubs are likely to use any of the common library | |
e22ea452 | 15443 | subroutines which @code{@value{NGCC}} generates as inline code. |
104c1213 JM |
15444 | |
15445 | ||
6d2ebf8b | 15446 | @node Debug Session |
79a6e687 | 15447 | @subsection Putting it All Together |
104c1213 JM |
15448 | |
15449 | @cindex remote serial debugging summary | |
15450 | In summary, when your program is ready to debug, you must follow these | |
15451 | steps. | |
15452 | ||
15453 | @enumerate | |
15454 | @item | |
6d2ebf8b | 15455 | Make sure you have defined the supporting low-level routines |
79a6e687 | 15456 | (@pxref{Bootstrapping,,What You Must Do for the Stub}): |
104c1213 JM |
15457 | @display |
15458 | @code{getDebugChar}, @code{putDebugChar}, | |
15459 | @code{flush_i_cache}, @code{memset}, @code{exceptionHandler}. | |
15460 | @end display | |
15461 | ||
15462 | @item | |
15463 | Insert these lines near the top of your program: | |
15464 | ||
474c8240 | 15465 | @smallexample |
104c1213 JM |
15466 | set_debug_traps(); |
15467 | breakpoint(); | |
474c8240 | 15468 | @end smallexample |
104c1213 JM |
15469 | |
15470 | @item | |
15471 | For the 680x0 stub only, you need to provide a variable called | |
15472 | @code{exceptionHook}. Normally you just use: | |
15473 | ||
474c8240 | 15474 | @smallexample |
104c1213 | 15475 | void (*exceptionHook)() = 0; |
474c8240 | 15476 | @end smallexample |
104c1213 | 15477 | |
d4f3574e | 15478 | @noindent |
104c1213 | 15479 | but if before calling @code{set_debug_traps}, you set it to point to a |
598ca718 | 15480 | function in your program, that function is called when |
104c1213 JM |
15481 | @code{@value{GDBN}} continues after stopping on a trap (for example, bus |
15482 | error). The function indicated by @code{exceptionHook} is called with | |
15483 | one parameter: an @code{int} which is the exception number. | |
15484 | ||
15485 | @item | |
15486 | Compile and link together: your program, the @value{GDBN} debugging stub for | |
15487 | your target architecture, and the supporting subroutines. | |
15488 | ||
15489 | @item | |
15490 | Make sure you have a serial connection between your target machine and | |
15491 | the @value{GDBN} host, and identify the serial port on the host. | |
15492 | ||
15493 | @item | |
15494 | @c The "remote" target now provides a `load' command, so we should | |
15495 | @c document that. FIXME. | |
15496 | Download your program to your target machine (or get it there by | |
15497 | whatever means the manufacturer provides), and start it. | |
15498 | ||
15499 | @item | |
07f31aa6 | 15500 | Start @value{GDBN} on the host, and connect to the target |
79a6e687 | 15501 | (@pxref{Connecting,,Connecting to a Remote Target}). |
9db8d71f | 15502 | |
104c1213 JM |
15503 | @end enumerate |
15504 | ||
8e04817f AC |
15505 | @node Configurations |
15506 | @chapter Configuration-Specific Information | |
104c1213 | 15507 | |
8e04817f AC |
15508 | While nearly all @value{GDBN} commands are available for all native and |
15509 | cross versions of the debugger, there are some exceptions. This chapter | |
15510 | describes things that are only available in certain configurations. | |
104c1213 | 15511 | |
8e04817f AC |
15512 | There are three major categories of configurations: native |
15513 | configurations, where the host and target are the same, embedded | |
15514 | operating system configurations, which are usually the same for several | |
15515 | different processor architectures, and bare embedded processors, which | |
15516 | are quite different from each other. | |
104c1213 | 15517 | |
8e04817f AC |
15518 | @menu |
15519 | * Native:: | |
15520 | * Embedded OS:: | |
15521 | * Embedded Processors:: | |
15522 | * Architectures:: | |
15523 | @end menu | |
104c1213 | 15524 | |
8e04817f AC |
15525 | @node Native |
15526 | @section Native | |
104c1213 | 15527 | |
8e04817f AC |
15528 | This section describes details specific to particular native |
15529 | configurations. | |
6cf7e474 | 15530 | |
8e04817f AC |
15531 | @menu |
15532 | * HP-UX:: HP-UX | |
7561d450 | 15533 | * BSD libkvm Interface:: Debugging BSD kernel memory images |
8e04817f AC |
15534 | * SVR4 Process Information:: SVR4 process information |
15535 | * DJGPP Native:: Features specific to the DJGPP port | |
78c47bea | 15536 | * Cygwin Native:: Features specific to the Cygwin port |
14d6dd68 | 15537 | * Hurd Native:: Features specific to @sc{gnu} Hurd |
a64548ea | 15538 | * Neutrino:: Features specific to QNX Neutrino |
a80b95ba | 15539 | * Darwin:: Features specific to Darwin |
8e04817f | 15540 | @end menu |
6cf7e474 | 15541 | |
8e04817f AC |
15542 | @node HP-UX |
15543 | @subsection HP-UX | |
104c1213 | 15544 | |
8e04817f AC |
15545 | On HP-UX systems, if you refer to a function or variable name that |
15546 | begins with a dollar sign, @value{GDBN} searches for a user or system | |
15547 | name first, before it searches for a convenience variable. | |
104c1213 | 15548 | |
9c16f35a | 15549 | |
7561d450 MK |
15550 | @node BSD libkvm Interface |
15551 | @subsection BSD libkvm Interface | |
15552 | ||
15553 | @cindex libkvm | |
15554 | @cindex kernel memory image | |
15555 | @cindex kernel crash dump | |
15556 | ||
15557 | BSD-derived systems (FreeBSD/NetBSD/OpenBSD) have a kernel memory | |
15558 | interface that provides a uniform interface for accessing kernel virtual | |
15559 | memory images, including live systems and crash dumps. @value{GDBN} | |
15560 | uses this interface to allow you to debug live kernels and kernel crash | |
15561 | dumps on many native BSD configurations. This is implemented as a | |
15562 | special @code{kvm} debugging target. For debugging a live system, load | |
15563 | the currently running kernel into @value{GDBN} and connect to the | |
15564 | @code{kvm} target: | |
15565 | ||
15566 | @smallexample | |
15567 | (@value{GDBP}) @b{target kvm} | |
15568 | @end smallexample | |
15569 | ||
15570 | For debugging crash dumps, provide the file name of the crash dump as an | |
15571 | argument: | |
15572 | ||
15573 | @smallexample | |
15574 | (@value{GDBP}) @b{target kvm /var/crash/bsd.0} | |
15575 | @end smallexample | |
15576 | ||
15577 | Once connected to the @code{kvm} target, the following commands are | |
15578 | available: | |
15579 | ||
15580 | @table @code | |
15581 | @kindex kvm | |
15582 | @item kvm pcb | |
721c2651 | 15583 | Set current context from the @dfn{Process Control Block} (PCB) address. |
7561d450 MK |
15584 | |
15585 | @item kvm proc | |
15586 | Set current context from proc address. This command isn't available on | |
15587 | modern FreeBSD systems. | |
15588 | @end table | |
15589 | ||
8e04817f | 15590 | @node SVR4 Process Information |
79a6e687 | 15591 | @subsection SVR4 Process Information |
60bf7e09 EZ |
15592 | @cindex /proc |
15593 | @cindex examine process image | |
15594 | @cindex process info via @file{/proc} | |
104c1213 | 15595 | |
60bf7e09 EZ |
15596 | Many versions of SVR4 and compatible systems provide a facility called |
15597 | @samp{/proc} that can be used to examine the image of a running | |
15598 | process using file-system subroutines. If @value{GDBN} is configured | |
15599 | for an operating system with this facility, the command @code{info | |
15600 | proc} is available to report information about the process running | |
15601 | your program, or about any process running on your system. @code{info | |
15602 | proc} works only on SVR4 systems that include the @code{procfs} code. | |
15603 | This includes, as of this writing, @sc{gnu}/Linux, OSF/1 (Digital | |
15604 | Unix), Solaris, Irix, and Unixware, but not HP-UX, for example. | |
104c1213 | 15605 | |
8e04817f AC |
15606 | @table @code |
15607 | @kindex info proc | |
60bf7e09 | 15608 | @cindex process ID |
8e04817f | 15609 | @item info proc |
60bf7e09 EZ |
15610 | @itemx info proc @var{process-id} |
15611 | Summarize available information about any running process. If a | |
15612 | process ID is specified by @var{process-id}, display information about | |
15613 | that process; otherwise display information about the program being | |
15614 | debugged. The summary includes the debugged process ID, the command | |
15615 | line used to invoke it, its current working directory, and its | |
15616 | executable file's absolute file name. | |
15617 | ||
15618 | On some systems, @var{process-id} can be of the form | |
15619 | @samp{[@var{pid}]/@var{tid}} which specifies a certain thread ID | |
15620 | within a process. If the optional @var{pid} part is missing, it means | |
15621 | a thread from the process being debugged (the leading @samp{/} still | |
15622 | needs to be present, or else @value{GDBN} will interpret the number as | |
15623 | a process ID rather than a thread ID). | |
6cf7e474 | 15624 | |
8e04817f | 15625 | @item info proc mappings |
60bf7e09 EZ |
15626 | @cindex memory address space mappings |
15627 | Report the memory address space ranges accessible in the program, with | |
15628 | information on whether the process has read, write, or execute access | |
15629 | rights to each range. On @sc{gnu}/Linux systems, each memory range | |
15630 | includes the object file which is mapped to that range, instead of the | |
15631 | memory access rights to that range. | |
15632 | ||
15633 | @item info proc stat | |
15634 | @itemx info proc status | |
15635 | @cindex process detailed status information | |
15636 | These subcommands are specific to @sc{gnu}/Linux systems. They show | |
15637 | the process-related information, including the user ID and group ID; | |
15638 | how many threads are there in the process; its virtual memory usage; | |
15639 | the signals that are pending, blocked, and ignored; its TTY; its | |
15640 | consumption of system and user time; its stack size; its @samp{nice} | |
2eecc4ab | 15641 | value; etc. For more information, see the @samp{proc} man page |
60bf7e09 EZ |
15642 | (type @kbd{man 5 proc} from your shell prompt). |
15643 | ||
15644 | @item info proc all | |
15645 | Show all the information about the process described under all of the | |
15646 | above @code{info proc} subcommands. | |
15647 | ||
8e04817f AC |
15648 | @ignore |
15649 | @comment These sub-options of 'info proc' were not included when | |
15650 | @comment procfs.c was re-written. Keep their descriptions around | |
15651 | @comment against the day when someone finds the time to put them back in. | |
15652 | @kindex info proc times | |
15653 | @item info proc times | |
15654 | Starting time, user CPU time, and system CPU time for your program and | |
15655 | its children. | |
6cf7e474 | 15656 | |
8e04817f AC |
15657 | @kindex info proc id |
15658 | @item info proc id | |
15659 | Report on the process IDs related to your program: its own process ID, | |
15660 | the ID of its parent, the process group ID, and the session ID. | |
8e04817f | 15661 | @end ignore |
721c2651 EZ |
15662 | |
15663 | @item set procfs-trace | |
15664 | @kindex set procfs-trace | |
15665 | @cindex @code{procfs} API calls | |
15666 | This command enables and disables tracing of @code{procfs} API calls. | |
15667 | ||
15668 | @item show procfs-trace | |
15669 | @kindex show procfs-trace | |
15670 | Show the current state of @code{procfs} API call tracing. | |
15671 | ||
15672 | @item set procfs-file @var{file} | |
15673 | @kindex set procfs-file | |
15674 | Tell @value{GDBN} to write @code{procfs} API trace to the named | |
15675 | @var{file}. @value{GDBN} appends the trace info to the previous | |
15676 | contents of the file. The default is to display the trace on the | |
15677 | standard output. | |
15678 | ||
15679 | @item show procfs-file | |
15680 | @kindex show procfs-file | |
15681 | Show the file to which @code{procfs} API trace is written. | |
15682 | ||
15683 | @item proc-trace-entry | |
15684 | @itemx proc-trace-exit | |
15685 | @itemx proc-untrace-entry | |
15686 | @itemx proc-untrace-exit | |
15687 | @kindex proc-trace-entry | |
15688 | @kindex proc-trace-exit | |
15689 | @kindex proc-untrace-entry | |
15690 | @kindex proc-untrace-exit | |
15691 | These commands enable and disable tracing of entries into and exits | |
15692 | from the @code{syscall} interface. | |
15693 | ||
15694 | @item info pidlist | |
15695 | @kindex info pidlist | |
15696 | @cindex process list, QNX Neutrino | |
15697 | For QNX Neutrino only, this command displays the list of all the | |
15698 | processes and all the threads within each process. | |
15699 | ||
15700 | @item info meminfo | |
15701 | @kindex info meminfo | |
15702 | @cindex mapinfo list, QNX Neutrino | |
15703 | For QNX Neutrino only, this command displays the list of all mapinfos. | |
8e04817f | 15704 | @end table |
104c1213 | 15705 | |
8e04817f AC |
15706 | @node DJGPP Native |
15707 | @subsection Features for Debugging @sc{djgpp} Programs | |
15708 | @cindex @sc{djgpp} debugging | |
15709 | @cindex native @sc{djgpp} debugging | |
15710 | @cindex MS-DOS-specific commands | |
104c1213 | 15711 | |
514c4d71 EZ |
15712 | @cindex DPMI |
15713 | @sc{djgpp} is a port of the @sc{gnu} development tools to MS-DOS and | |
8e04817f AC |
15714 | MS-Windows. @sc{djgpp} programs are 32-bit protected-mode programs |
15715 | that use the @dfn{DPMI} (DOS Protected-Mode Interface) API to run on | |
15716 | top of real-mode DOS systems and their emulations. | |
104c1213 | 15717 | |
8e04817f AC |
15718 | @value{GDBN} supports native debugging of @sc{djgpp} programs, and |
15719 | defines a few commands specific to the @sc{djgpp} port. This | |
15720 | subsection describes those commands. | |
104c1213 | 15721 | |
8e04817f AC |
15722 | @table @code |
15723 | @kindex info dos | |
15724 | @item info dos | |
15725 | This is a prefix of @sc{djgpp}-specific commands which print | |
15726 | information about the target system and important OS structures. | |
f1251bdd | 15727 | |
8e04817f AC |
15728 | @kindex sysinfo |
15729 | @cindex MS-DOS system info | |
15730 | @cindex free memory information (MS-DOS) | |
15731 | @item info dos sysinfo | |
15732 | This command displays assorted information about the underlying | |
15733 | platform: the CPU type and features, the OS version and flavor, the | |
15734 | DPMI version, and the available conventional and DPMI memory. | |
104c1213 | 15735 | |
8e04817f AC |
15736 | @cindex GDT |
15737 | @cindex LDT | |
15738 | @cindex IDT | |
15739 | @cindex segment descriptor tables | |
15740 | @cindex descriptor tables display | |
15741 | @item info dos gdt | |
15742 | @itemx info dos ldt | |
15743 | @itemx info dos idt | |
15744 | These 3 commands display entries from, respectively, Global, Local, | |
15745 | and Interrupt Descriptor Tables (GDT, LDT, and IDT). The descriptor | |
15746 | tables are data structures which store a descriptor for each segment | |
15747 | that is currently in use. The segment's selector is an index into a | |
15748 | descriptor table; the table entry for that index holds the | |
15749 | descriptor's base address and limit, and its attributes and access | |
15750 | rights. | |
104c1213 | 15751 | |
8e04817f AC |
15752 | A typical @sc{djgpp} program uses 3 segments: a code segment, a data |
15753 | segment (used for both data and the stack), and a DOS segment (which | |
15754 | allows access to DOS/BIOS data structures and absolute addresses in | |
15755 | conventional memory). However, the DPMI host will usually define | |
15756 | additional segments in order to support the DPMI environment. | |
d4f3574e | 15757 | |
8e04817f AC |
15758 | @cindex garbled pointers |
15759 | These commands allow to display entries from the descriptor tables. | |
15760 | Without an argument, all entries from the specified table are | |
15761 | displayed. An argument, which should be an integer expression, means | |
15762 | display a single entry whose index is given by the argument. For | |
15763 | example, here's a convenient way to display information about the | |
15764 | debugged program's data segment: | |
104c1213 | 15765 | |
8e04817f AC |
15766 | @smallexample |
15767 | @exdent @code{(@value{GDBP}) info dos ldt $ds} | |
15768 | @exdent @code{0x13f: base=0x11970000 limit=0x0009ffff 32-Bit Data (Read/Write, Exp-up)} | |
15769 | @end smallexample | |
104c1213 | 15770 | |
8e04817f AC |
15771 | @noindent |
15772 | This comes in handy when you want to see whether a pointer is outside | |
15773 | the data segment's limit (i.e.@: @dfn{garbled}). | |
104c1213 | 15774 | |
8e04817f AC |
15775 | @cindex page tables display (MS-DOS) |
15776 | @item info dos pde | |
15777 | @itemx info dos pte | |
15778 | These two commands display entries from, respectively, the Page | |
15779 | Directory and the Page Tables. Page Directories and Page Tables are | |
15780 | data structures which control how virtual memory addresses are mapped | |
15781 | into physical addresses. A Page Table includes an entry for every | |
15782 | page of memory that is mapped into the program's address space; there | |
15783 | may be several Page Tables, each one holding up to 4096 entries. A | |
15784 | Page Directory has up to 4096 entries, one each for every Page Table | |
15785 | that is currently in use. | |
104c1213 | 15786 | |
8e04817f AC |
15787 | Without an argument, @kbd{info dos pde} displays the entire Page |
15788 | Directory, and @kbd{info dos pte} displays all the entries in all of | |
15789 | the Page Tables. An argument, an integer expression, given to the | |
15790 | @kbd{info dos pde} command means display only that entry from the Page | |
15791 | Directory table. An argument given to the @kbd{info dos pte} command | |
15792 | means display entries from a single Page Table, the one pointed to by | |
15793 | the specified entry in the Page Directory. | |
104c1213 | 15794 | |
8e04817f AC |
15795 | @cindex direct memory access (DMA) on MS-DOS |
15796 | These commands are useful when your program uses @dfn{DMA} (Direct | |
15797 | Memory Access), which needs physical addresses to program the DMA | |
15798 | controller. | |
104c1213 | 15799 | |
8e04817f | 15800 | These commands are supported only with some DPMI servers. |
104c1213 | 15801 | |
8e04817f AC |
15802 | @cindex physical address from linear address |
15803 | @item info dos address-pte @var{addr} | |
15804 | This command displays the Page Table entry for a specified linear | |
514c4d71 EZ |
15805 | address. The argument @var{addr} is a linear address which should |
15806 | already have the appropriate segment's base address added to it, | |
15807 | because this command accepts addresses which may belong to @emph{any} | |
15808 | segment. For example, here's how to display the Page Table entry for | |
15809 | the page where a variable @code{i} is stored: | |
104c1213 | 15810 | |
b383017d | 15811 | @smallexample |
8e04817f AC |
15812 | @exdent @code{(@value{GDBP}) info dos address-pte __djgpp_base_address + (char *)&i} |
15813 | @exdent @code{Page Table entry for address 0x11a00d30:} | |
b383017d | 15814 | @exdent @code{Base=0x02698000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0xd30} |
8e04817f | 15815 | @end smallexample |
104c1213 | 15816 | |
8e04817f AC |
15817 | @noindent |
15818 | This says that @code{i} is stored at offset @code{0xd30} from the page | |
514c4d71 | 15819 | whose physical base address is @code{0x02698000}, and shows all the |
8e04817f | 15820 | attributes of that page. |
104c1213 | 15821 | |
8e04817f AC |
15822 | Note that you must cast the addresses of variables to a @code{char *}, |
15823 | since otherwise the value of @code{__djgpp_base_address}, the base | |
15824 | address of all variables and functions in a @sc{djgpp} program, will | |
15825 | be added using the rules of C pointer arithmetics: if @code{i} is | |
15826 | declared an @code{int}, @value{GDBN} will add 4 times the value of | |
15827 | @code{__djgpp_base_address} to the address of @code{i}. | |
104c1213 | 15828 | |
8e04817f AC |
15829 | Here's another example, it displays the Page Table entry for the |
15830 | transfer buffer: | |
104c1213 | 15831 | |
8e04817f AC |
15832 | @smallexample |
15833 | @exdent @code{(@value{GDBP}) info dos address-pte *((unsigned *)&_go32_info_block + 3)} | |
15834 | @exdent @code{Page Table entry for address 0x29110:} | |
15835 | @exdent @code{Base=0x00029000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0x110} | |
15836 | @end smallexample | |
104c1213 | 15837 | |
8e04817f AC |
15838 | @noindent |
15839 | (The @code{+ 3} offset is because the transfer buffer's address is the | |
514c4d71 EZ |
15840 | 3rd member of the @code{_go32_info_block} structure.) The output |
15841 | clearly shows that this DPMI server maps the addresses in conventional | |
15842 | memory 1:1, i.e.@: the physical (@code{0x00029000} + @code{0x110}) and | |
15843 | linear (@code{0x29110}) addresses are identical. | |
104c1213 | 15844 | |
8e04817f AC |
15845 | This command is supported only with some DPMI servers. |
15846 | @end table | |
104c1213 | 15847 | |
c45da7e6 | 15848 | @cindex DOS serial data link, remote debugging |
a8f24a35 EZ |
15849 | In addition to native debugging, the DJGPP port supports remote |
15850 | debugging via a serial data link. The following commands are specific | |
15851 | to remote serial debugging in the DJGPP port of @value{GDBN}. | |
15852 | ||
15853 | @table @code | |
15854 | @kindex set com1base | |
15855 | @kindex set com1irq | |
15856 | @kindex set com2base | |
15857 | @kindex set com2irq | |
15858 | @kindex set com3base | |
15859 | @kindex set com3irq | |
15860 | @kindex set com4base | |
15861 | @kindex set com4irq | |
15862 | @item set com1base @var{addr} | |
15863 | This command sets the base I/O port address of the @file{COM1} serial | |
15864 | port. | |
15865 | ||
15866 | @item set com1irq @var{irq} | |
15867 | This command sets the @dfn{Interrupt Request} (@code{IRQ}) line to use | |
15868 | for the @file{COM1} serial port. | |
15869 | ||
15870 | There are similar commands @samp{set com2base}, @samp{set com3irq}, | |
15871 | etc.@: for setting the port address and the @code{IRQ} lines for the | |
15872 | other 3 COM ports. | |
15873 | ||
15874 | @kindex show com1base | |
15875 | @kindex show com1irq | |
15876 | @kindex show com2base | |
15877 | @kindex show com2irq | |
15878 | @kindex show com3base | |
15879 | @kindex show com3irq | |
15880 | @kindex show com4base | |
15881 | @kindex show com4irq | |
15882 | The related commands @samp{show com1base}, @samp{show com1irq} etc.@: | |
15883 | display the current settings of the base address and the @code{IRQ} | |
15884 | lines used by the COM ports. | |
c45da7e6 EZ |
15885 | |
15886 | @item info serial | |
15887 | @kindex info serial | |
15888 | @cindex DOS serial port status | |
15889 | This command prints the status of the 4 DOS serial ports. For each | |
15890 | port, it prints whether it's active or not, its I/O base address and | |
15891 | IRQ number, whether it uses a 16550-style FIFO, its baudrate, and the | |
15892 | counts of various errors encountered so far. | |
a8f24a35 EZ |
15893 | @end table |
15894 | ||
15895 | ||
78c47bea | 15896 | @node Cygwin Native |
79a6e687 | 15897 | @subsection Features for Debugging MS Windows PE Executables |
78c47bea PM |
15898 | @cindex MS Windows debugging |
15899 | @cindex native Cygwin debugging | |
15900 | @cindex Cygwin-specific commands | |
15901 | ||
be448670 | 15902 | @value{GDBN} supports native debugging of MS Windows programs, including |
db2e3e2e BW |
15903 | DLLs with and without symbolic debugging information. There are various |
15904 | additional Cygwin-specific commands, described in this section. | |
15905 | Working with DLLs that have no debugging symbols is described in | |
15906 | @ref{Non-debug DLL Symbols}. | |
78c47bea PM |
15907 | |
15908 | @table @code | |
15909 | @kindex info w32 | |
15910 | @item info w32 | |
db2e3e2e | 15911 | This is a prefix of MS Windows-specific commands which print |
78c47bea PM |
15912 | information about the target system and important OS structures. |
15913 | ||
15914 | @item info w32 selector | |
15915 | This command displays information returned by | |
15916 | the Win32 API @code{GetThreadSelectorEntry} function. | |
15917 | It takes an optional argument that is evaluated to | |
15918 | a long value to give the information about this given selector. | |
15919 | Without argument, this command displays information | |
d3e8051b | 15920 | about the six segment registers. |
78c47bea PM |
15921 | |
15922 | @kindex info dll | |
15923 | @item info dll | |
db2e3e2e | 15924 | This is a Cygwin-specific alias of @code{info shared}. |
78c47bea PM |
15925 | |
15926 | @kindex dll-symbols | |
15927 | @item dll-symbols | |
15928 | This command loads symbols from a dll similarly to | |
15929 | add-sym command but without the need to specify a base address. | |
15930 | ||
be90c084 | 15931 | @kindex set cygwin-exceptions |
e16b02ee EZ |
15932 | @cindex debugging the Cygwin DLL |
15933 | @cindex Cygwin DLL, debugging | |
be90c084 | 15934 | @item set cygwin-exceptions @var{mode} |
e16b02ee EZ |
15935 | If @var{mode} is @code{on}, @value{GDBN} will break on exceptions that |
15936 | happen inside the Cygwin DLL. If @var{mode} is @code{off}, | |
15937 | @value{GDBN} will delay recognition of exceptions, and may ignore some | |
15938 | exceptions which seem to be caused by internal Cygwin DLL | |
15939 | ``bookkeeping''. This option is meant primarily for debugging the | |
15940 | Cygwin DLL itself; the default value is @code{off} to avoid annoying | |
15941 | @value{GDBN} users with false @code{SIGSEGV} signals. | |
be90c084 CF |
15942 | |
15943 | @kindex show cygwin-exceptions | |
15944 | @item show cygwin-exceptions | |
e16b02ee EZ |
15945 | Displays whether @value{GDBN} will break on exceptions that happen |
15946 | inside the Cygwin DLL itself. | |
be90c084 | 15947 | |
b383017d | 15948 | @kindex set new-console |
78c47bea | 15949 | @item set new-console @var{mode} |
b383017d | 15950 | If @var{mode} is @code{on} the debuggee will |
78c47bea PM |
15951 | be started in a new console on next start. |
15952 | If @var{mode} is @code{off}i, the debuggee will | |
15953 | be started in the same console as the debugger. | |
15954 | ||
15955 | @kindex show new-console | |
15956 | @item show new-console | |
15957 | Displays whether a new console is used | |
15958 | when the debuggee is started. | |
15959 | ||
15960 | @kindex set new-group | |
15961 | @item set new-group @var{mode} | |
15962 | This boolean value controls whether the debuggee should | |
15963 | start a new group or stay in the same group as the debugger. | |
15964 | This affects the way the Windows OS handles | |
c8aa23ab | 15965 | @samp{Ctrl-C}. |
78c47bea PM |
15966 | |
15967 | @kindex show new-group | |
15968 | @item show new-group | |
15969 | Displays current value of new-group boolean. | |
15970 | ||
15971 | @kindex set debugevents | |
15972 | @item set debugevents | |
219eec71 EZ |
15973 | This boolean value adds debug output concerning kernel events related |
15974 | to the debuggee seen by the debugger. This includes events that | |
15975 | signal thread and process creation and exit, DLL loading and | |
15976 | unloading, console interrupts, and debugging messages produced by the | |
15977 | Windows @code{OutputDebugString} API call. | |
78c47bea PM |
15978 | |
15979 | @kindex set debugexec | |
15980 | @item set debugexec | |
b383017d | 15981 | This boolean value adds debug output concerning execute events |
219eec71 | 15982 | (such as resume thread) seen by the debugger. |
78c47bea PM |
15983 | |
15984 | @kindex set debugexceptions | |
15985 | @item set debugexceptions | |
219eec71 EZ |
15986 | This boolean value adds debug output concerning exceptions in the |
15987 | debuggee seen by the debugger. | |
78c47bea PM |
15988 | |
15989 | @kindex set debugmemory | |
15990 | @item set debugmemory | |
219eec71 EZ |
15991 | This boolean value adds debug output concerning debuggee memory reads |
15992 | and writes by the debugger. | |
78c47bea PM |
15993 | |
15994 | @kindex set shell | |
15995 | @item set shell | |
15996 | This boolean values specifies whether the debuggee is called | |
15997 | via a shell or directly (default value is on). | |
15998 | ||
15999 | @kindex show shell | |
16000 | @item show shell | |
16001 | Displays if the debuggee will be started with a shell. | |
16002 | ||
16003 | @end table | |
16004 | ||
be448670 | 16005 | @menu |
79a6e687 | 16006 | * Non-debug DLL Symbols:: Support for DLLs without debugging symbols |
be448670 CF |
16007 | @end menu |
16008 | ||
79a6e687 BW |
16009 | @node Non-debug DLL Symbols |
16010 | @subsubsection Support for DLLs without Debugging Symbols | |
be448670 CF |
16011 | @cindex DLLs with no debugging symbols |
16012 | @cindex Minimal symbols and DLLs | |
16013 | ||
16014 | Very often on windows, some of the DLLs that your program relies on do | |
16015 | not include symbolic debugging information (for example, | |
db2e3e2e | 16016 | @file{kernel32.dll}). When @value{GDBN} doesn't recognize any debugging |
be448670 | 16017 | symbols in a DLL, it relies on the minimal amount of symbolic |
db2e3e2e | 16018 | information contained in the DLL's export table. This section |
be448670 CF |
16019 | describes working with such symbols, known internally to @value{GDBN} as |
16020 | ``minimal symbols''. | |
16021 | ||
16022 | Note that before the debugged program has started execution, no DLLs | |
db2e3e2e | 16023 | will have been loaded. The easiest way around this problem is simply to |
be448670 | 16024 | start the program --- either by setting a breakpoint or letting the |
db2e3e2e | 16025 | program run once to completion. It is also possible to force |
be448670 | 16026 | @value{GDBN} to load a particular DLL before starting the executable --- |
12c27660 | 16027 | see the shared library information in @ref{Files}, or the |
db2e3e2e | 16028 | @code{dll-symbols} command in @ref{Cygwin Native}. Currently, |
be448670 CF |
16029 | explicitly loading symbols from a DLL with no debugging information will |
16030 | cause the symbol names to be duplicated in @value{GDBN}'s lookup table, | |
16031 | which may adversely affect symbol lookup performance. | |
16032 | ||
79a6e687 | 16033 | @subsubsection DLL Name Prefixes |
be448670 CF |
16034 | |
16035 | In keeping with the naming conventions used by the Microsoft debugging | |
16036 | tools, DLL export symbols are made available with a prefix based on the | |
16037 | DLL name, for instance @code{KERNEL32!CreateFileA}. The plain name is | |
16038 | also entered into the symbol table, so @code{CreateFileA} is often | |
99e008fe | 16039 | sufficient. In some cases there will be name clashes within a program |
be448670 CF |
16040 | (particularly if the executable itself includes full debugging symbols) |
16041 | necessitating the use of the fully qualified name when referring to the | |
99e008fe | 16042 | contents of the DLL. Use single-quotes around the name to avoid the |
be448670 CF |
16043 | exclamation mark (``!'') being interpreted as a language operator. |
16044 | ||
16045 | Note that the internal name of the DLL may be all upper-case, even | |
99e008fe | 16046 | though the file name of the DLL is lower-case, or vice-versa. Since |
be448670 CF |
16047 | symbols within @value{GDBN} are @emph{case-sensitive} this may cause |
16048 | some confusion. If in doubt, try the @code{info functions} and | |
0869d01b NR |
16049 | @code{info variables} commands or even @code{maint print msymbols} |
16050 | (@pxref{Symbols}). Here's an example: | |
be448670 CF |
16051 | |
16052 | @smallexample | |
f7dc1244 | 16053 | (@value{GDBP}) info function CreateFileA |
be448670 CF |
16054 | All functions matching regular expression "CreateFileA": |
16055 | ||
16056 | Non-debugging symbols: | |
16057 | 0x77e885f4 CreateFileA | |
16058 | 0x77e885f4 KERNEL32!CreateFileA | |
16059 | @end smallexample | |
16060 | ||
16061 | @smallexample | |
f7dc1244 | 16062 | (@value{GDBP}) info function ! |
be448670 CF |
16063 | All functions matching regular expression "!": |
16064 | ||
16065 | Non-debugging symbols: | |
16066 | 0x6100114c cygwin1!__assert | |
16067 | 0x61004034 cygwin1!_dll_crt0@@0 | |
16068 | 0x61004240 cygwin1!dll_crt0(per_process *) | |
16069 | [etc...] | |
16070 | @end smallexample | |
16071 | ||
79a6e687 | 16072 | @subsubsection Working with Minimal Symbols |
be448670 CF |
16073 | |
16074 | Symbols extracted from a DLL's export table do not contain very much | |
16075 | type information. All that @value{GDBN} can do is guess whether a symbol | |
16076 | refers to a function or variable depending on the linker section that | |
16077 | contains the symbol. Also note that the actual contents of the memory | |
16078 | contained in a DLL are not available unless the program is running. This | |
16079 | means that you cannot examine the contents of a variable or disassemble | |
16080 | a function within a DLL without a running program. | |
16081 | ||
16082 | Variables are generally treated as pointers and dereferenced | |
16083 | automatically. For this reason, it is often necessary to prefix a | |
16084 | variable name with the address-of operator (``&'') and provide explicit | |
16085 | type information in the command. Here's an example of the type of | |
16086 | problem: | |
16087 | ||
16088 | @smallexample | |
f7dc1244 | 16089 | (@value{GDBP}) print 'cygwin1!__argv' |
be448670 CF |
16090 | $1 = 268572168 |
16091 | @end smallexample | |
16092 | ||
16093 | @smallexample | |
f7dc1244 | 16094 | (@value{GDBP}) x 'cygwin1!__argv' |
be448670 CF |
16095 | 0x10021610: "\230y\"" |
16096 | @end smallexample | |
16097 | ||
16098 | And two possible solutions: | |
16099 | ||
16100 | @smallexample | |
f7dc1244 | 16101 | (@value{GDBP}) print ((char **)'cygwin1!__argv')[0] |
be448670 CF |
16102 | $2 = 0x22fd98 "/cygdrive/c/mydirectory/myprogram" |
16103 | @end smallexample | |
16104 | ||
16105 | @smallexample | |
f7dc1244 | 16106 | (@value{GDBP}) x/2x &'cygwin1!__argv' |
be448670 | 16107 | 0x610c0aa8 <cygwin1!__argv>: 0x10021608 0x00000000 |
f7dc1244 | 16108 | (@value{GDBP}) x/x 0x10021608 |
be448670 | 16109 | 0x10021608: 0x0022fd98 |
f7dc1244 | 16110 | (@value{GDBP}) x/s 0x0022fd98 |
be448670 CF |
16111 | 0x22fd98: "/cygdrive/c/mydirectory/myprogram" |
16112 | @end smallexample | |
16113 | ||
16114 | Setting a break point within a DLL is possible even before the program | |
16115 | starts execution. However, under these circumstances, @value{GDBN} can't | |
16116 | examine the initial instructions of the function in order to skip the | |
16117 | function's frame set-up code. You can work around this by using ``*&'' | |
16118 | to set the breakpoint at a raw memory address: | |
16119 | ||
16120 | @smallexample | |
f7dc1244 | 16121 | (@value{GDBP}) break *&'python22!PyOS_Readline' |
be448670 CF |
16122 | Breakpoint 1 at 0x1e04eff0 |
16123 | @end smallexample | |
16124 | ||
16125 | The author of these extensions is not entirely convinced that setting a | |
16126 | break point within a shared DLL like @file{kernel32.dll} is completely | |
16127 | safe. | |
16128 | ||
14d6dd68 | 16129 | @node Hurd Native |
79a6e687 | 16130 | @subsection Commands Specific to @sc{gnu} Hurd Systems |
14d6dd68 EZ |
16131 | @cindex @sc{gnu} Hurd debugging |
16132 | ||
16133 | This subsection describes @value{GDBN} commands specific to the | |
16134 | @sc{gnu} Hurd native debugging. | |
16135 | ||
16136 | @table @code | |
16137 | @item set signals | |
16138 | @itemx set sigs | |
16139 | @kindex set signals@r{, Hurd command} | |
16140 | @kindex set sigs@r{, Hurd command} | |
16141 | This command toggles the state of inferior signal interception by | |
16142 | @value{GDBN}. Mach exceptions, such as breakpoint traps, are not | |
16143 | affected by this command. @code{sigs} is a shorthand alias for | |
16144 | @code{signals}. | |
16145 | ||
16146 | @item show signals | |
16147 | @itemx show sigs | |
16148 | @kindex show signals@r{, Hurd command} | |
16149 | @kindex show sigs@r{, Hurd command} | |
16150 | Show the current state of intercepting inferior's signals. | |
16151 | ||
16152 | @item set signal-thread | |
16153 | @itemx set sigthread | |
16154 | @kindex set signal-thread | |
16155 | @kindex set sigthread | |
16156 | This command tells @value{GDBN} which thread is the @code{libc} signal | |
16157 | thread. That thread is run when a signal is delivered to a running | |
16158 | process. @code{set sigthread} is the shorthand alias of @code{set | |
16159 | signal-thread}. | |
16160 | ||
16161 | @item show signal-thread | |
16162 | @itemx show sigthread | |
16163 | @kindex show signal-thread | |
16164 | @kindex show sigthread | |
16165 | These two commands show which thread will run when the inferior is | |
16166 | delivered a signal. | |
16167 | ||
16168 | @item set stopped | |
16169 | @kindex set stopped@r{, Hurd command} | |
16170 | This commands tells @value{GDBN} that the inferior process is stopped, | |
16171 | as with the @code{SIGSTOP} signal. The stopped process can be | |
16172 | continued by delivering a signal to it. | |
16173 | ||
16174 | @item show stopped | |
16175 | @kindex show stopped@r{, Hurd command} | |
16176 | This command shows whether @value{GDBN} thinks the debuggee is | |
16177 | stopped. | |
16178 | ||
16179 | @item set exceptions | |
16180 | @kindex set exceptions@r{, Hurd command} | |
16181 | Use this command to turn off trapping of exceptions in the inferior. | |
16182 | When exception trapping is off, neither breakpoints nor | |
16183 | single-stepping will work. To restore the default, set exception | |
16184 | trapping on. | |
16185 | ||
16186 | @item show exceptions | |
16187 | @kindex show exceptions@r{, Hurd command} | |
16188 | Show the current state of trapping exceptions in the inferior. | |
16189 | ||
16190 | @item set task pause | |
16191 | @kindex set task@r{, Hurd commands} | |
16192 | @cindex task attributes (@sc{gnu} Hurd) | |
16193 | @cindex pause current task (@sc{gnu} Hurd) | |
16194 | This command toggles task suspension when @value{GDBN} has control. | |
16195 | Setting it to on takes effect immediately, and the task is suspended | |
16196 | whenever @value{GDBN} gets control. Setting it to off will take | |
16197 | effect the next time the inferior is continued. If this option is set | |
16198 | to off, you can use @code{set thread default pause on} or @code{set | |
16199 | thread pause on} (see below) to pause individual threads. | |
16200 | ||
16201 | @item show task pause | |
16202 | @kindex show task@r{, Hurd commands} | |
16203 | Show the current state of task suspension. | |
16204 | ||
16205 | @item set task detach-suspend-count | |
16206 | @cindex task suspend count | |
16207 | @cindex detach from task, @sc{gnu} Hurd | |
16208 | This command sets the suspend count the task will be left with when | |
16209 | @value{GDBN} detaches from it. | |
16210 | ||
16211 | @item show task detach-suspend-count | |
16212 | Show the suspend count the task will be left with when detaching. | |
16213 | ||
16214 | @item set task exception-port | |
16215 | @itemx set task excp | |
16216 | @cindex task exception port, @sc{gnu} Hurd | |
16217 | This command sets the task exception port to which @value{GDBN} will | |
16218 | forward exceptions. The argument should be the value of the @dfn{send | |
16219 | rights} of the task. @code{set task excp} is a shorthand alias. | |
16220 | ||
16221 | @item set noninvasive | |
16222 | @cindex noninvasive task options | |
16223 | This command switches @value{GDBN} to a mode that is the least | |
16224 | invasive as far as interfering with the inferior is concerned. This | |
16225 | is the same as using @code{set task pause}, @code{set exceptions}, and | |
16226 | @code{set signals} to values opposite to the defaults. | |
16227 | ||
16228 | @item info send-rights | |
16229 | @itemx info receive-rights | |
16230 | @itemx info port-rights | |
16231 | @itemx info port-sets | |
16232 | @itemx info dead-names | |
16233 | @itemx info ports | |
16234 | @itemx info psets | |
16235 | @cindex send rights, @sc{gnu} Hurd | |
16236 | @cindex receive rights, @sc{gnu} Hurd | |
16237 | @cindex port rights, @sc{gnu} Hurd | |
16238 | @cindex port sets, @sc{gnu} Hurd | |
16239 | @cindex dead names, @sc{gnu} Hurd | |
16240 | These commands display information about, respectively, send rights, | |
16241 | receive rights, port rights, port sets, and dead names of a task. | |
16242 | There are also shorthand aliases: @code{info ports} for @code{info | |
16243 | port-rights} and @code{info psets} for @code{info port-sets}. | |
16244 | ||
16245 | @item set thread pause | |
16246 | @kindex set thread@r{, Hurd command} | |
16247 | @cindex thread properties, @sc{gnu} Hurd | |
16248 | @cindex pause current thread (@sc{gnu} Hurd) | |
16249 | This command toggles current thread suspension when @value{GDBN} has | |
16250 | control. Setting it to on takes effect immediately, and the current | |
16251 | thread is suspended whenever @value{GDBN} gets control. Setting it to | |
16252 | off will take effect the next time the inferior is continued. | |
16253 | Normally, this command has no effect, since when @value{GDBN} has | |
16254 | control, the whole task is suspended. However, if you used @code{set | |
16255 | task pause off} (see above), this command comes in handy to suspend | |
16256 | only the current thread. | |
16257 | ||
16258 | @item show thread pause | |
16259 | @kindex show thread@r{, Hurd command} | |
16260 | This command shows the state of current thread suspension. | |
16261 | ||
16262 | @item set thread run | |
d3e8051b | 16263 | This command sets whether the current thread is allowed to run. |
14d6dd68 EZ |
16264 | |
16265 | @item show thread run | |
16266 | Show whether the current thread is allowed to run. | |
16267 | ||
16268 | @item set thread detach-suspend-count | |
16269 | @cindex thread suspend count, @sc{gnu} Hurd | |
16270 | @cindex detach from thread, @sc{gnu} Hurd | |
16271 | This command sets the suspend count @value{GDBN} will leave on a | |
16272 | thread when detaching. This number is relative to the suspend count | |
16273 | found by @value{GDBN} when it notices the thread; use @code{set thread | |
16274 | takeover-suspend-count} to force it to an absolute value. | |
16275 | ||
16276 | @item show thread detach-suspend-count | |
16277 | Show the suspend count @value{GDBN} will leave on the thread when | |
16278 | detaching. | |
16279 | ||
16280 | @item set thread exception-port | |
16281 | @itemx set thread excp | |
16282 | Set the thread exception port to which to forward exceptions. This | |
16283 | overrides the port set by @code{set task exception-port} (see above). | |
16284 | @code{set thread excp} is the shorthand alias. | |
16285 | ||
16286 | @item set thread takeover-suspend-count | |
16287 | Normally, @value{GDBN}'s thread suspend counts are relative to the | |
16288 | value @value{GDBN} finds when it notices each thread. This command | |
16289 | changes the suspend counts to be absolute instead. | |
16290 | ||
16291 | @item set thread default | |
16292 | @itemx show thread default | |
16293 | @cindex thread default settings, @sc{gnu} Hurd | |
16294 | Each of the above @code{set thread} commands has a @code{set thread | |
16295 | default} counterpart (e.g., @code{set thread default pause}, @code{set | |
16296 | thread default exception-port}, etc.). The @code{thread default} | |
16297 | variety of commands sets the default thread properties for all | |
16298 | threads; you can then change the properties of individual threads with | |
16299 | the non-default commands. | |
16300 | @end table | |
16301 | ||
16302 | ||
a64548ea EZ |
16303 | @node Neutrino |
16304 | @subsection QNX Neutrino | |
16305 | @cindex QNX Neutrino | |
16306 | ||
16307 | @value{GDBN} provides the following commands specific to the QNX | |
16308 | Neutrino target: | |
16309 | ||
16310 | @table @code | |
16311 | @item set debug nto-debug | |
16312 | @kindex set debug nto-debug | |
16313 | When set to on, enables debugging messages specific to the QNX | |
16314 | Neutrino support. | |
16315 | ||
16316 | @item show debug nto-debug | |
16317 | @kindex show debug nto-debug | |
16318 | Show the current state of QNX Neutrino messages. | |
16319 | @end table | |
16320 | ||
a80b95ba TG |
16321 | @node Darwin |
16322 | @subsection Darwin | |
16323 | @cindex Darwin | |
16324 | ||
16325 | @value{GDBN} provides the following commands specific to the Darwin target: | |
16326 | ||
16327 | @table @code | |
16328 | @item set debug darwin @var{num} | |
16329 | @kindex set debug darwin | |
16330 | When set to a non zero value, enables debugging messages specific to | |
16331 | the Darwin support. Higher values produce more verbose output. | |
16332 | ||
16333 | @item show debug darwin | |
16334 | @kindex show debug darwin | |
16335 | Show the current state of Darwin messages. | |
16336 | ||
16337 | @item set debug mach-o @var{num} | |
16338 | @kindex set debug mach-o | |
16339 | When set to a non zero value, enables debugging messages while | |
16340 | @value{GDBN} is reading Darwin object files. (@dfn{Mach-O} is the | |
16341 | file format used on Darwin for object and executable files.) Higher | |
16342 | values produce more verbose output. This is a command to diagnose | |
16343 | problems internal to @value{GDBN} and should not be needed in normal | |
16344 | usage. | |
16345 | ||
16346 | @item show debug mach-o | |
16347 | @kindex show debug mach-o | |
16348 | Show the current state of Mach-O file messages. | |
16349 | ||
16350 | @item set mach-exceptions on | |
16351 | @itemx set mach-exceptions off | |
16352 | @kindex set mach-exceptions | |
16353 | On Darwin, faults are first reported as a Mach exception and are then | |
16354 | mapped to a Posix signal. Use this command to turn on trapping of | |
16355 | Mach exceptions in the inferior. This might be sometimes useful to | |
16356 | better understand the cause of a fault. The default is off. | |
16357 | ||
16358 | @item show mach-exceptions | |
16359 | @kindex show mach-exceptions | |
16360 | Show the current state of exceptions trapping. | |
16361 | @end table | |
16362 | ||
a64548ea | 16363 | |
8e04817f AC |
16364 | @node Embedded OS |
16365 | @section Embedded Operating Systems | |
104c1213 | 16366 | |
8e04817f AC |
16367 | This section describes configurations involving the debugging of |
16368 | embedded operating systems that are available for several different | |
16369 | architectures. | |
d4f3574e | 16370 | |
8e04817f AC |
16371 | @menu |
16372 | * VxWorks:: Using @value{GDBN} with VxWorks | |
16373 | @end menu | |
104c1213 | 16374 | |
8e04817f AC |
16375 | @value{GDBN} includes the ability to debug programs running on |
16376 | various real-time operating systems. | |
104c1213 | 16377 | |
8e04817f AC |
16378 | @node VxWorks |
16379 | @subsection Using @value{GDBN} with VxWorks | |
104c1213 | 16380 | |
8e04817f | 16381 | @cindex VxWorks |
104c1213 | 16382 | |
8e04817f | 16383 | @table @code |
104c1213 | 16384 | |
8e04817f AC |
16385 | @kindex target vxworks |
16386 | @item target vxworks @var{machinename} | |
16387 | A VxWorks system, attached via TCP/IP. The argument @var{machinename} | |
16388 | is the target system's machine name or IP address. | |
104c1213 | 16389 | |
8e04817f | 16390 | @end table |
104c1213 | 16391 | |
8e04817f AC |
16392 | On VxWorks, @code{load} links @var{filename} dynamically on the |
16393 | current target system as well as adding its symbols in @value{GDBN}. | |
104c1213 | 16394 | |
8e04817f AC |
16395 | @value{GDBN} enables developers to spawn and debug tasks running on networked |
16396 | VxWorks targets from a Unix host. Already-running tasks spawned from | |
16397 | the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on | |
16398 | both the Unix host and on the VxWorks target. The program | |
16399 | @code{@value{GDBP}} is installed and executed on the Unix host. (It may be | |
16400 | installed with the name @code{vxgdb}, to distinguish it from a | |
16401 | @value{GDBN} for debugging programs on the host itself.) | |
104c1213 | 16402 | |
8e04817f AC |
16403 | @table @code |
16404 | @item VxWorks-timeout @var{args} | |
16405 | @kindex vxworks-timeout | |
16406 | All VxWorks-based targets now support the option @code{vxworks-timeout}. | |
16407 | This option is set by the user, and @var{args} represents the number of | |
16408 | seconds @value{GDBN} waits for responses to rpc's. You might use this if | |
16409 | your VxWorks target is a slow software simulator or is on the far side | |
16410 | of a thin network line. | |
16411 | @end table | |
104c1213 | 16412 | |
8e04817f AC |
16413 | The following information on connecting to VxWorks was current when |
16414 | this manual was produced; newer releases of VxWorks may use revised | |
16415 | procedures. | |
104c1213 | 16416 | |
4644b6e3 | 16417 | @findex INCLUDE_RDB |
8e04817f AC |
16418 | To use @value{GDBN} with VxWorks, you must rebuild your VxWorks kernel |
16419 | to include the remote debugging interface routines in the VxWorks | |
16420 | library @file{rdb.a}. To do this, define @code{INCLUDE_RDB} in the | |
16421 | VxWorks configuration file @file{configAll.h} and rebuild your VxWorks | |
16422 | kernel. The resulting kernel contains @file{rdb.a}, and spawns the | |
16423 | source debugging task @code{tRdbTask} when VxWorks is booted. For more | |
16424 | information on configuring and remaking VxWorks, see the manufacturer's | |
16425 | manual. | |
16426 | @c VxWorks, see the @cite{VxWorks Programmer's Guide}. | |
104c1213 | 16427 | |
8e04817f AC |
16428 | Once you have included @file{rdb.a} in your VxWorks system image and set |
16429 | your Unix execution search path to find @value{GDBN}, you are ready to | |
16430 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} (or | |
16431 | @code{vxgdb}, depending on your installation). | |
104c1213 | 16432 | |
8e04817f | 16433 | @value{GDBN} comes up showing the prompt: |
104c1213 | 16434 | |
474c8240 | 16435 | @smallexample |
8e04817f | 16436 | (vxgdb) |
474c8240 | 16437 | @end smallexample |
104c1213 | 16438 | |
8e04817f AC |
16439 | @menu |
16440 | * VxWorks Connection:: Connecting to VxWorks | |
16441 | * VxWorks Download:: VxWorks download | |
16442 | * VxWorks Attach:: Running tasks | |
16443 | @end menu | |
104c1213 | 16444 | |
8e04817f AC |
16445 | @node VxWorks Connection |
16446 | @subsubsection Connecting to VxWorks | |
104c1213 | 16447 | |
8e04817f AC |
16448 | The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the |
16449 | network. To connect to a target whose host name is ``@code{tt}'', type: | |
104c1213 | 16450 | |
474c8240 | 16451 | @smallexample |
8e04817f | 16452 | (vxgdb) target vxworks tt |
474c8240 | 16453 | @end smallexample |
104c1213 | 16454 | |
8e04817f AC |
16455 | @need 750 |
16456 | @value{GDBN} displays messages like these: | |
104c1213 | 16457 | |
8e04817f AC |
16458 | @smallexample |
16459 | Attaching remote machine across net... | |
16460 | Connected to tt. | |
16461 | @end smallexample | |
104c1213 | 16462 | |
8e04817f AC |
16463 | @need 1000 |
16464 | @value{GDBN} then attempts to read the symbol tables of any object modules | |
16465 | loaded into the VxWorks target since it was last booted. @value{GDBN} locates | |
16466 | these files by searching the directories listed in the command search | |
79a6e687 | 16467 | path (@pxref{Environment, ,Your Program's Environment}); if it fails |
8e04817f | 16468 | to find an object file, it displays a message such as: |
5d161b24 | 16469 | |
474c8240 | 16470 | @smallexample |
8e04817f | 16471 | prog.o: No such file or directory. |
474c8240 | 16472 | @end smallexample |
104c1213 | 16473 | |
8e04817f AC |
16474 | When this happens, add the appropriate directory to the search path with |
16475 | the @value{GDBN} command @code{path}, and execute the @code{target} | |
16476 | command again. | |
104c1213 | 16477 | |
8e04817f | 16478 | @node VxWorks Download |
79a6e687 | 16479 | @subsubsection VxWorks Download |
104c1213 | 16480 | |
8e04817f AC |
16481 | @cindex download to VxWorks |
16482 | If you have connected to the VxWorks target and you want to debug an | |
16483 | object that has not yet been loaded, you can use the @value{GDBN} | |
16484 | @code{load} command to download a file from Unix to VxWorks | |
16485 | incrementally. The object file given as an argument to the @code{load} | |
16486 | command is actually opened twice: first by the VxWorks target in order | |
16487 | to download the code, then by @value{GDBN} in order to read the symbol | |
16488 | table. This can lead to problems if the current working directories on | |
16489 | the two systems differ. If both systems have NFS mounted the same | |
16490 | filesystems, you can avoid these problems by using absolute paths. | |
16491 | Otherwise, it is simplest to set the working directory on both systems | |
16492 | to the directory in which the object file resides, and then to reference | |
16493 | the file by its name, without any path. For instance, a program | |
16494 | @file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks | |
16495 | and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this | |
16496 | program, type this on VxWorks: | |
104c1213 | 16497 | |
474c8240 | 16498 | @smallexample |
8e04817f | 16499 | -> cd "@var{vxpath}/vw/demo/rdb" |
474c8240 | 16500 | @end smallexample |
104c1213 | 16501 | |
8e04817f AC |
16502 | @noindent |
16503 | Then, in @value{GDBN}, type: | |
104c1213 | 16504 | |
474c8240 | 16505 | @smallexample |
8e04817f AC |
16506 | (vxgdb) cd @var{hostpath}/vw/demo/rdb |
16507 | (vxgdb) load prog.o | |
474c8240 | 16508 | @end smallexample |
104c1213 | 16509 | |
8e04817f | 16510 | @value{GDBN} displays a response similar to this: |
104c1213 | 16511 | |
8e04817f AC |
16512 | @smallexample |
16513 | Reading symbol data from wherever/vw/demo/rdb/prog.o... done. | |
16514 | @end smallexample | |
104c1213 | 16515 | |
8e04817f AC |
16516 | You can also use the @code{load} command to reload an object module |
16517 | after editing and recompiling the corresponding source file. Note that | |
16518 | this makes @value{GDBN} delete all currently-defined breakpoints, | |
16519 | auto-displays, and convenience variables, and to clear the value | |
16520 | history. (This is necessary in order to preserve the integrity of | |
16521 | debugger's data structures that reference the target system's symbol | |
16522 | table.) | |
104c1213 | 16523 | |
8e04817f | 16524 | @node VxWorks Attach |
79a6e687 | 16525 | @subsubsection Running Tasks |
104c1213 JM |
16526 | |
16527 | @cindex running VxWorks tasks | |
16528 | You can also attach to an existing task using the @code{attach} command as | |
16529 | follows: | |
16530 | ||
474c8240 | 16531 | @smallexample |
104c1213 | 16532 | (vxgdb) attach @var{task} |
474c8240 | 16533 | @end smallexample |
104c1213 JM |
16534 | |
16535 | @noindent | |
16536 | where @var{task} is the VxWorks hexadecimal task ID. The task can be running | |
16537 | or suspended when you attach to it. Running tasks are suspended at | |
16538 | the time of attachment. | |
16539 | ||
6d2ebf8b | 16540 | @node Embedded Processors |
104c1213 JM |
16541 | @section Embedded Processors |
16542 | ||
16543 | This section goes into details specific to particular embedded | |
16544 | configurations. | |
16545 | ||
c45da7e6 EZ |
16546 | @cindex send command to simulator |
16547 | Whenever a specific embedded processor has a simulator, @value{GDBN} | |
16548 | allows to send an arbitrary command to the simulator. | |
16549 | ||
16550 | @table @code | |
16551 | @item sim @var{command} | |
16552 | @kindex sim@r{, a command} | |
16553 | Send an arbitrary @var{command} string to the simulator. Consult the | |
16554 | documentation for the specific simulator in use for information about | |
16555 | acceptable commands. | |
16556 | @end table | |
16557 | ||
7d86b5d5 | 16558 | |
104c1213 | 16559 | @menu |
c45da7e6 | 16560 | * ARM:: ARM RDI |
172c2a43 | 16561 | * M32R/D:: Renesas M32R/D |
104c1213 | 16562 | * M68K:: Motorola M68K |
104c1213 | 16563 | * MIPS Embedded:: MIPS Embedded |
a37295f9 | 16564 | * OpenRISC 1000:: OpenRisc 1000 |
104c1213 | 16565 | * PA:: HP PA Embedded |
4acd40f3 | 16566 | * PowerPC Embedded:: PowerPC Embedded |
104c1213 JM |
16567 | * Sparclet:: Tsqware Sparclet |
16568 | * Sparclite:: Fujitsu Sparclite | |
104c1213 | 16569 | * Z8000:: Zilog Z8000 |
a64548ea EZ |
16570 | * AVR:: Atmel AVR |
16571 | * CRIS:: CRIS | |
16572 | * Super-H:: Renesas Super-H | |
104c1213 JM |
16573 | @end menu |
16574 | ||
6d2ebf8b | 16575 | @node ARM |
104c1213 | 16576 | @subsection ARM |
c45da7e6 | 16577 | @cindex ARM RDI |
104c1213 JM |
16578 | |
16579 | @table @code | |
8e04817f AC |
16580 | @kindex target rdi |
16581 | @item target rdi @var{dev} | |
16582 | ARM Angel monitor, via RDI library interface to ADP protocol. You may | |
16583 | use this target to communicate with both boards running the Angel | |
16584 | monitor, or with the EmbeddedICE JTAG debug device. | |
16585 | ||
16586 | @kindex target rdp | |
16587 | @item target rdp @var{dev} | |
16588 | ARM Demon monitor. | |
16589 | ||
16590 | @end table | |
16591 | ||
e2f4edfd EZ |
16592 | @value{GDBN} provides the following ARM-specific commands: |
16593 | ||
16594 | @table @code | |
16595 | @item set arm disassembler | |
16596 | @kindex set arm | |
16597 | This commands selects from a list of disassembly styles. The | |
16598 | @code{"std"} style is the standard style. | |
16599 | ||
16600 | @item show arm disassembler | |
16601 | @kindex show arm | |
16602 | Show the current disassembly style. | |
16603 | ||
16604 | @item set arm apcs32 | |
16605 | @cindex ARM 32-bit mode | |
16606 | This command toggles ARM operation mode between 32-bit and 26-bit. | |
16607 | ||
16608 | @item show arm apcs32 | |
16609 | Display the current usage of the ARM 32-bit mode. | |
16610 | ||
16611 | @item set arm fpu @var{fputype} | |
16612 | This command sets the ARM floating-point unit (FPU) type. The | |
16613 | argument @var{fputype} can be one of these: | |
16614 | ||
16615 | @table @code | |
16616 | @item auto | |
16617 | Determine the FPU type by querying the OS ABI. | |
16618 | @item softfpa | |
16619 | Software FPU, with mixed-endian doubles on little-endian ARM | |
16620 | processors. | |
16621 | @item fpa | |
16622 | GCC-compiled FPA co-processor. | |
16623 | @item softvfp | |
16624 | Software FPU with pure-endian doubles. | |
16625 | @item vfp | |
16626 | VFP co-processor. | |
16627 | @end table | |
16628 | ||
16629 | @item show arm fpu | |
16630 | Show the current type of the FPU. | |
16631 | ||
16632 | @item set arm abi | |
16633 | This command forces @value{GDBN} to use the specified ABI. | |
16634 | ||
16635 | @item show arm abi | |
16636 | Show the currently used ABI. | |
16637 | ||
0428b8f5 DJ |
16638 | @item set arm fallback-mode (arm|thumb|auto) |
16639 | @value{GDBN} uses the symbol table, when available, to determine | |
16640 | whether instructions are ARM or Thumb. This command controls | |
16641 | @value{GDBN}'s default behavior when the symbol table is not | |
16642 | available. The default is @samp{auto}, which causes @value{GDBN} to | |
16643 | use the current execution mode (from the @code{T} bit in the @code{CPSR} | |
16644 | register). | |
16645 | ||
16646 | @item show arm fallback-mode | |
16647 | Show the current fallback instruction mode. | |
16648 | ||
16649 | @item set arm force-mode (arm|thumb|auto) | |
16650 | This command overrides use of the symbol table to determine whether | |
16651 | instructions are ARM or Thumb. The default is @samp{auto}, which | |
16652 | causes @value{GDBN} to use the symbol table and then the setting | |
16653 | of @samp{set arm fallback-mode}. | |
16654 | ||
16655 | @item show arm force-mode | |
16656 | Show the current forced instruction mode. | |
16657 | ||
e2f4edfd EZ |
16658 | @item set debug arm |
16659 | Toggle whether to display ARM-specific debugging messages from the ARM | |
16660 | target support subsystem. | |
16661 | ||
16662 | @item show debug arm | |
16663 | Show whether ARM-specific debugging messages are enabled. | |
16664 | @end table | |
16665 | ||
c45da7e6 EZ |
16666 | The following commands are available when an ARM target is debugged |
16667 | using the RDI interface: | |
16668 | ||
16669 | @table @code | |
16670 | @item rdilogfile @r{[}@var{file}@r{]} | |
16671 | @kindex rdilogfile | |
16672 | @cindex ADP (Angel Debugger Protocol) logging | |
16673 | Set the filename for the ADP (Angel Debugger Protocol) packet log. | |
16674 | With an argument, sets the log file to the specified @var{file}. With | |
16675 | no argument, show the current log file name. The default log file is | |
16676 | @file{rdi.log}. | |
16677 | ||
16678 | @item rdilogenable @r{[}@var{arg}@r{]} | |
16679 | @kindex rdilogenable | |
16680 | Control logging of ADP packets. With an argument of 1 or @code{"yes"} | |
16681 | enables logging, with an argument 0 or @code{"no"} disables it. With | |
16682 | no arguments displays the current setting. When logging is enabled, | |
16683 | ADP packets exchanged between @value{GDBN} and the RDI target device | |
16684 | are logged to a file. | |
16685 | ||
16686 | @item set rdiromatzero | |
16687 | @kindex set rdiromatzero | |
16688 | @cindex ROM at zero address, RDI | |
16689 | Tell @value{GDBN} whether the target has ROM at address 0. If on, | |
16690 | vector catching is disabled, so that zero address can be used. If off | |
16691 | (the default), vector catching is enabled. For this command to take | |
16692 | effect, it needs to be invoked prior to the @code{target rdi} command. | |
16693 | ||
16694 | @item show rdiromatzero | |
16695 | @kindex show rdiromatzero | |
16696 | Show the current setting of ROM at zero address. | |
16697 | ||
16698 | @item set rdiheartbeat | |
16699 | @kindex set rdiheartbeat | |
16700 | @cindex RDI heartbeat | |
16701 | Enable or disable RDI heartbeat packets. It is not recommended to | |
16702 | turn on this option, since it confuses ARM and EPI JTAG interface, as | |
16703 | well as the Angel monitor. | |
16704 | ||
16705 | @item show rdiheartbeat | |
16706 | @kindex show rdiheartbeat | |
16707 | Show the setting of RDI heartbeat packets. | |
16708 | @end table | |
16709 | ||
e2f4edfd | 16710 | |
8e04817f | 16711 | @node M32R/D |
ba04e063 | 16712 | @subsection Renesas M32R/D and M32R/SDI |
8e04817f AC |
16713 | |
16714 | @table @code | |
8e04817f AC |
16715 | @kindex target m32r |
16716 | @item target m32r @var{dev} | |
172c2a43 | 16717 | Renesas M32R/D ROM monitor. |
8e04817f | 16718 | |
fb3e19c0 KI |
16719 | @kindex target m32rsdi |
16720 | @item target m32rsdi @var{dev} | |
16721 | Renesas M32R SDI server, connected via parallel port to the board. | |
721c2651 EZ |
16722 | @end table |
16723 | ||
16724 | The following @value{GDBN} commands are specific to the M32R monitor: | |
16725 | ||
16726 | @table @code | |
16727 | @item set download-path @var{path} | |
16728 | @kindex set download-path | |
16729 | @cindex find downloadable @sc{srec} files (M32R) | |
d3e8051b | 16730 | Set the default path for finding downloadable @sc{srec} files. |
721c2651 EZ |
16731 | |
16732 | @item show download-path | |
16733 | @kindex show download-path | |
16734 | Show the default path for downloadable @sc{srec} files. | |
fb3e19c0 | 16735 | |
721c2651 EZ |
16736 | @item set board-address @var{addr} |
16737 | @kindex set board-address | |
16738 | @cindex M32-EVA target board address | |
16739 | Set the IP address for the M32R-EVA target board. | |
16740 | ||
16741 | @item show board-address | |
16742 | @kindex show board-address | |
16743 | Show the current IP address of the target board. | |
16744 | ||
16745 | @item set server-address @var{addr} | |
16746 | @kindex set server-address | |
16747 | @cindex download server address (M32R) | |
16748 | Set the IP address for the download server, which is the @value{GDBN}'s | |
16749 | host machine. | |
16750 | ||
16751 | @item show server-address | |
16752 | @kindex show server-address | |
16753 | Display the IP address of the download server. | |
16754 | ||
16755 | @item upload @r{[}@var{file}@r{]} | |
16756 | @kindex upload@r{, M32R} | |
16757 | Upload the specified @sc{srec} @var{file} via the monitor's Ethernet | |
16758 | upload capability. If no @var{file} argument is given, the current | |
16759 | executable file is uploaded. | |
16760 | ||
16761 | @item tload @r{[}@var{file}@r{]} | |
16762 | @kindex tload@r{, M32R} | |
16763 | Test the @code{upload} command. | |
8e04817f AC |
16764 | @end table |
16765 | ||
ba04e063 EZ |
16766 | The following commands are available for M32R/SDI: |
16767 | ||
16768 | @table @code | |
16769 | @item sdireset | |
16770 | @kindex sdireset | |
16771 | @cindex reset SDI connection, M32R | |
16772 | This command resets the SDI connection. | |
16773 | ||
16774 | @item sdistatus | |
16775 | @kindex sdistatus | |
16776 | This command shows the SDI connection status. | |
16777 | ||
16778 | @item debug_chaos | |
16779 | @kindex debug_chaos | |
16780 | @cindex M32R/Chaos debugging | |
16781 | Instructs the remote that M32R/Chaos debugging is to be used. | |
16782 | ||
16783 | @item use_debug_dma | |
16784 | @kindex use_debug_dma | |
16785 | Instructs the remote to use the DEBUG_DMA method of accessing memory. | |
16786 | ||
16787 | @item use_mon_code | |
16788 | @kindex use_mon_code | |
16789 | Instructs the remote to use the MON_CODE method of accessing memory. | |
16790 | ||
16791 | @item use_ib_break | |
16792 | @kindex use_ib_break | |
16793 | Instructs the remote to set breakpoints by IB break. | |
16794 | ||
16795 | @item use_dbt_break | |
16796 | @kindex use_dbt_break | |
16797 | Instructs the remote to set breakpoints by DBT. | |
16798 | @end table | |
16799 | ||
8e04817f AC |
16800 | @node M68K |
16801 | @subsection M68k | |
16802 | ||
7ce59000 DJ |
16803 | The Motorola m68k configuration includes ColdFire support, and a |
16804 | target command for the following ROM monitor. | |
8e04817f AC |
16805 | |
16806 | @table @code | |
16807 | ||
8e04817f AC |
16808 | @kindex target dbug |
16809 | @item target dbug @var{dev} | |
16810 | dBUG ROM monitor for Motorola ColdFire. | |
16811 | ||
8e04817f AC |
16812 | @end table |
16813 | ||
8e04817f AC |
16814 | @node MIPS Embedded |
16815 | @subsection MIPS Embedded | |
16816 | ||
16817 | @cindex MIPS boards | |
16818 | @value{GDBN} can use the MIPS remote debugging protocol to talk to a | |
16819 | MIPS board attached to a serial line. This is available when | |
16820 | you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}. | |
104c1213 | 16821 | |
8e04817f AC |
16822 | @need 1000 |
16823 | Use these @value{GDBN} commands to specify the connection to your target board: | |
104c1213 | 16824 | |
8e04817f AC |
16825 | @table @code |
16826 | @item target mips @var{port} | |
16827 | @kindex target mips @var{port} | |
16828 | To run a program on the board, start up @code{@value{GDBP}} with the | |
16829 | name of your program as the argument. To connect to the board, use the | |
16830 | command @samp{target mips @var{port}}, where @var{port} is the name of | |
16831 | the serial port connected to the board. If the program has not already | |
16832 | been downloaded to the board, you may use the @code{load} command to | |
16833 | download it. You can then use all the usual @value{GDBN} commands. | |
104c1213 | 16834 | |
8e04817f AC |
16835 | For example, this sequence connects to the target board through a serial |
16836 | port, and loads and runs a program called @var{prog} through the | |
16837 | debugger: | |
104c1213 | 16838 | |
474c8240 | 16839 | @smallexample |
8e04817f AC |
16840 | host$ @value{GDBP} @var{prog} |
16841 | @value{GDBN} is free software and @dots{} | |
16842 | (@value{GDBP}) target mips /dev/ttyb | |
16843 | (@value{GDBP}) load @var{prog} | |
16844 | (@value{GDBP}) run | |
474c8240 | 16845 | @end smallexample |
104c1213 | 16846 | |
8e04817f AC |
16847 | @item target mips @var{hostname}:@var{portnumber} |
16848 | On some @value{GDBN} host configurations, you can specify a TCP | |
16849 | connection (for instance, to a serial line managed by a terminal | |
16850 | concentrator) instead of a serial port, using the syntax | |
16851 | @samp{@var{hostname}:@var{portnumber}}. | |
104c1213 | 16852 | |
8e04817f AC |
16853 | @item target pmon @var{port} |
16854 | @kindex target pmon @var{port} | |
16855 | PMON ROM monitor. | |
104c1213 | 16856 | |
8e04817f AC |
16857 | @item target ddb @var{port} |
16858 | @kindex target ddb @var{port} | |
16859 | NEC's DDB variant of PMON for Vr4300. | |
104c1213 | 16860 | |
8e04817f AC |
16861 | @item target lsi @var{port} |
16862 | @kindex target lsi @var{port} | |
16863 | LSI variant of PMON. | |
104c1213 | 16864 | |
8e04817f AC |
16865 | @kindex target r3900 |
16866 | @item target r3900 @var{dev} | |
16867 | Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips. | |
104c1213 | 16868 | |
8e04817f AC |
16869 | @kindex target array |
16870 | @item target array @var{dev} | |
16871 | Array Tech LSI33K RAID controller board. | |
104c1213 | 16872 | |
8e04817f | 16873 | @end table |
104c1213 | 16874 | |
104c1213 | 16875 | |
8e04817f AC |
16876 | @noindent |
16877 | @value{GDBN} also supports these special commands for MIPS targets: | |
104c1213 | 16878 | |
8e04817f | 16879 | @table @code |
8e04817f AC |
16880 | @item set mipsfpu double |
16881 | @itemx set mipsfpu single | |
16882 | @itemx set mipsfpu none | |
a64548ea | 16883 | @itemx set mipsfpu auto |
8e04817f AC |
16884 | @itemx show mipsfpu |
16885 | @kindex set mipsfpu | |
16886 | @kindex show mipsfpu | |
16887 | @cindex MIPS remote floating point | |
16888 | @cindex floating point, MIPS remote | |
16889 | If your target board does not support the MIPS floating point | |
16890 | coprocessor, you should use the command @samp{set mipsfpu none} (if you | |
16891 | need this, you may wish to put the command in your @value{GDBN} init | |
16892 | file). This tells @value{GDBN} how to find the return value of | |
16893 | functions which return floating point values. It also allows | |
16894 | @value{GDBN} to avoid saving the floating point registers when calling | |
16895 | functions on the board. If you are using a floating point coprocessor | |
16896 | with only single precision floating point support, as on the @sc{r4650} | |
16897 | processor, use the command @samp{set mipsfpu single}. The default | |
16898 | double precision floating point coprocessor may be selected using | |
16899 | @samp{set mipsfpu double}. | |
104c1213 | 16900 | |
8e04817f AC |
16901 | In previous versions the only choices were double precision or no |
16902 | floating point, so @samp{set mipsfpu on} will select double precision | |
16903 | and @samp{set mipsfpu off} will select no floating point. | |
104c1213 | 16904 | |
8e04817f AC |
16905 | As usual, you can inquire about the @code{mipsfpu} variable with |
16906 | @samp{show mipsfpu}. | |
104c1213 | 16907 | |
8e04817f AC |
16908 | @item set timeout @var{seconds} |
16909 | @itemx set retransmit-timeout @var{seconds} | |
16910 | @itemx show timeout | |
16911 | @itemx show retransmit-timeout | |
16912 | @cindex @code{timeout}, MIPS protocol | |
16913 | @cindex @code{retransmit-timeout}, MIPS protocol | |
16914 | @kindex set timeout | |
16915 | @kindex show timeout | |
16916 | @kindex set retransmit-timeout | |
16917 | @kindex show retransmit-timeout | |
16918 | You can control the timeout used while waiting for a packet, in the MIPS | |
16919 | remote protocol, with the @code{set timeout @var{seconds}} command. The | |
16920 | default is 5 seconds. Similarly, you can control the timeout used while | |
a6f3e723 | 16921 | waiting for an acknowledgment of a packet with the @code{set |
8e04817f AC |
16922 | retransmit-timeout @var{seconds}} command. The default is 3 seconds. |
16923 | You can inspect both values with @code{show timeout} and @code{show | |
16924 | retransmit-timeout}. (These commands are @emph{only} available when | |
16925 | @value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.) | |
104c1213 | 16926 | |
8e04817f AC |
16927 | The timeout set by @code{set timeout} does not apply when @value{GDBN} |
16928 | is waiting for your program to stop. In that case, @value{GDBN} waits | |
16929 | forever because it has no way of knowing how long the program is going | |
16930 | to run before stopping. | |
ba04e063 EZ |
16931 | |
16932 | @item set syn-garbage-limit @var{num} | |
16933 | @kindex set syn-garbage-limit@r{, MIPS remote} | |
16934 | @cindex synchronize with remote MIPS target | |
16935 | Limit the maximum number of characters @value{GDBN} should ignore when | |
16936 | it tries to synchronize with the remote target. The default is 10 | |
16937 | characters. Setting the limit to -1 means there's no limit. | |
16938 | ||
16939 | @item show syn-garbage-limit | |
16940 | @kindex show syn-garbage-limit@r{, MIPS remote} | |
16941 | Show the current limit on the number of characters to ignore when | |
16942 | trying to synchronize with the remote system. | |
16943 | ||
16944 | @item set monitor-prompt @var{prompt} | |
16945 | @kindex set monitor-prompt@r{, MIPS remote} | |
16946 | @cindex remote monitor prompt | |
16947 | Tell @value{GDBN} to expect the specified @var{prompt} string from the | |
16948 | remote monitor. The default depends on the target: | |
16949 | @table @asis | |
16950 | @item pmon target | |
16951 | @samp{PMON} | |
16952 | @item ddb target | |
16953 | @samp{NEC010} | |
16954 | @item lsi target | |
16955 | @samp{PMON>} | |
16956 | @end table | |
16957 | ||
16958 | @item show monitor-prompt | |
16959 | @kindex show monitor-prompt@r{, MIPS remote} | |
16960 | Show the current strings @value{GDBN} expects as the prompt from the | |
16961 | remote monitor. | |
16962 | ||
16963 | @item set monitor-warnings | |
16964 | @kindex set monitor-warnings@r{, MIPS remote} | |
16965 | Enable or disable monitor warnings about hardware breakpoints. This | |
16966 | has effect only for the @code{lsi} target. When on, @value{GDBN} will | |
16967 | display warning messages whose codes are returned by the @code{lsi} | |
16968 | PMON monitor for breakpoint commands. | |
16969 | ||
16970 | @item show monitor-warnings | |
16971 | @kindex show monitor-warnings@r{, MIPS remote} | |
16972 | Show the current setting of printing monitor warnings. | |
16973 | ||
16974 | @item pmon @var{command} | |
16975 | @kindex pmon@r{, MIPS remote} | |
16976 | @cindex send PMON command | |
16977 | This command allows sending an arbitrary @var{command} string to the | |
16978 | monitor. The monitor must be in debug mode for this to work. | |
8e04817f | 16979 | @end table |
104c1213 | 16980 | |
a37295f9 MM |
16981 | @node OpenRISC 1000 |
16982 | @subsection OpenRISC 1000 | |
16983 | @cindex OpenRISC 1000 | |
16984 | ||
16985 | @cindex or1k boards | |
16986 | See OR1k Architecture document (@uref{www.opencores.org}) for more information | |
16987 | about platform and commands. | |
16988 | ||
16989 | @table @code | |
16990 | ||
16991 | @kindex target jtag | |
16992 | @item target jtag jtag://@var{host}:@var{port} | |
16993 | ||
16994 | Connects to remote JTAG server. | |
16995 | JTAG remote server can be either an or1ksim or JTAG server, | |
16996 | connected via parallel port to the board. | |
16997 | ||
16998 | Example: @code{target jtag jtag://localhost:9999} | |
16999 | ||
17000 | @kindex or1ksim | |
17001 | @item or1ksim @var{command} | |
17002 | If connected to @code{or1ksim} OpenRISC 1000 Architectural | |
17003 | Simulator, proprietary commands can be executed. | |
17004 | ||
17005 | @kindex info or1k spr | |
17006 | @item info or1k spr | |
17007 | Displays spr groups. | |
17008 | ||
17009 | @item info or1k spr @var{group} | |
17010 | @itemx info or1k spr @var{groupno} | |
17011 | Displays register names in selected group. | |
17012 | ||
17013 | @item info or1k spr @var{group} @var{register} | |
17014 | @itemx info or1k spr @var{register} | |
17015 | @itemx info or1k spr @var{groupno} @var{registerno} | |
17016 | @itemx info or1k spr @var{registerno} | |
17017 | Shows information about specified spr register. | |
17018 | ||
17019 | @kindex spr | |
17020 | @item spr @var{group} @var{register} @var{value} | |
17021 | @itemx spr @var{register @var{value}} | |
17022 | @itemx spr @var{groupno} @var{registerno @var{value}} | |
17023 | @itemx spr @var{registerno @var{value}} | |
17024 | Writes @var{value} to specified spr register. | |
17025 | @end table | |
17026 | ||
17027 | Some implementations of OpenRISC 1000 Architecture also have hardware trace. | |
17028 | It is very similar to @value{GDBN} trace, except it does not interfere with normal | |
17029 | program execution and is thus much faster. Hardware breakpoints/watchpoint | |
17030 | triggers can be set using: | |
17031 | @table @code | |
17032 | @item $LEA/$LDATA | |
17033 | Load effective address/data | |
17034 | @item $SEA/$SDATA | |
17035 | Store effective address/data | |
17036 | @item $AEA/$ADATA | |
17037 | Access effective address ($SEA or $LEA) or data ($SDATA/$LDATA) | |
17038 | @item $FETCH | |
17039 | Fetch data | |
17040 | @end table | |
17041 | ||
17042 | When triggered, it can capture low level data, like: @code{PC}, @code{LSEA}, | |
17043 | @code{LDATA}, @code{SDATA}, @code{READSPR}, @code{WRITESPR}, @code{INSTR}. | |
17044 | ||
17045 | @code{htrace} commands: | |
17046 | @cindex OpenRISC 1000 htrace | |
17047 | @table @code | |
17048 | @kindex hwatch | |
17049 | @item hwatch @var{conditional} | |
d3e8051b | 17050 | Set hardware watchpoint on combination of Load/Store Effective Address(es) |
a37295f9 MM |
17051 | or Data. For example: |
17052 | ||
17053 | @code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)} | |
17054 | ||
17055 | @code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)} | |
17056 | ||
4644b6e3 | 17057 | @kindex htrace |
a37295f9 MM |
17058 | @item htrace info |
17059 | Display information about current HW trace configuration. | |
17060 | ||
a37295f9 MM |
17061 | @item htrace trigger @var{conditional} |
17062 | Set starting criteria for HW trace. | |
17063 | ||
a37295f9 MM |
17064 | @item htrace qualifier @var{conditional} |
17065 | Set acquisition qualifier for HW trace. | |
17066 | ||
a37295f9 MM |
17067 | @item htrace stop @var{conditional} |
17068 | Set HW trace stopping criteria. | |
17069 | ||
f153cc92 | 17070 | @item htrace record [@var{data}]* |
a37295f9 MM |
17071 | Selects the data to be recorded, when qualifier is met and HW trace was |
17072 | triggered. | |
17073 | ||
a37295f9 | 17074 | @item htrace enable |
a37295f9 MM |
17075 | @itemx htrace disable |
17076 | Enables/disables the HW trace. | |
17077 | ||
f153cc92 | 17078 | @item htrace rewind [@var{filename}] |
a37295f9 MM |
17079 | Clears currently recorded trace data. |
17080 | ||
17081 | If filename is specified, new trace file is made and any newly collected data | |
17082 | will be written there. | |
17083 | ||
f153cc92 | 17084 | @item htrace print [@var{start} [@var{len}]] |
a37295f9 MM |
17085 | Prints trace buffer, using current record configuration. |
17086 | ||
a37295f9 MM |
17087 | @item htrace mode continuous |
17088 | Set continuous trace mode. | |
17089 | ||
a37295f9 MM |
17090 | @item htrace mode suspend |
17091 | Set suspend trace mode. | |
17092 | ||
17093 | @end table | |
17094 | ||
4acd40f3 TJB |
17095 | @node PowerPC Embedded |
17096 | @subsection PowerPC Embedded | |
104c1213 | 17097 | |
55eddb0f DJ |
17098 | @value{GDBN} provides the following PowerPC-specific commands: |
17099 | ||
104c1213 | 17100 | @table @code |
55eddb0f DJ |
17101 | @kindex set powerpc |
17102 | @item set powerpc soft-float | |
17103 | @itemx show powerpc soft-float | |
17104 | Force @value{GDBN} to use (or not use) a software floating point calling | |
17105 | convention. By default, @value{GDBN} selects the calling convention based | |
17106 | on the selected architecture and the provided executable file. | |
17107 | ||
17108 | @item set powerpc vector-abi | |
17109 | @itemx show powerpc vector-abi | |
17110 | Force @value{GDBN} to use the specified calling convention for vector | |
17111 | arguments and return values. The valid options are @samp{auto}; | |
17112 | @samp{generic}, to avoid vector registers even if they are present; | |
17113 | @samp{altivec}, to use AltiVec registers; and @samp{spe} to use SPE | |
17114 | registers. By default, @value{GDBN} selects the calling convention | |
17115 | based on the selected architecture and the provided executable file. | |
17116 | ||
8e04817f AC |
17117 | @kindex target dink32 |
17118 | @item target dink32 @var{dev} | |
17119 | DINK32 ROM monitor. | |
104c1213 | 17120 | |
8e04817f AC |
17121 | @kindex target ppcbug |
17122 | @item target ppcbug @var{dev} | |
17123 | @kindex target ppcbug1 | |
17124 | @item target ppcbug1 @var{dev} | |
17125 | PPCBUG ROM monitor for PowerPC. | |
104c1213 | 17126 | |
8e04817f AC |
17127 | @kindex target sds |
17128 | @item target sds @var{dev} | |
17129 | SDS monitor, running on a PowerPC board (such as Motorola's ADS). | |
c45da7e6 | 17130 | @end table |
8e04817f | 17131 | |
c45da7e6 | 17132 | @cindex SDS protocol |
d52fb0e9 | 17133 | The following commands specific to the SDS protocol are supported |
55eddb0f | 17134 | by @value{GDBN}: |
c45da7e6 EZ |
17135 | |
17136 | @table @code | |
17137 | @item set sdstimeout @var{nsec} | |
17138 | @kindex set sdstimeout | |
17139 | Set the timeout for SDS protocol reads to be @var{nsec} seconds. The | |
17140 | default is 2 seconds. | |
17141 | ||
17142 | @item show sdstimeout | |
17143 | @kindex show sdstimeout | |
17144 | Show the current value of the SDS timeout. | |
17145 | ||
17146 | @item sds @var{command} | |
17147 | @kindex sds@r{, a command} | |
17148 | Send the specified @var{command} string to the SDS monitor. | |
8e04817f AC |
17149 | @end table |
17150 | ||
c45da7e6 | 17151 | |
8e04817f AC |
17152 | @node PA |
17153 | @subsection HP PA Embedded | |
104c1213 JM |
17154 | |
17155 | @table @code | |
17156 | ||
8e04817f AC |
17157 | @kindex target op50n |
17158 | @item target op50n @var{dev} | |
17159 | OP50N monitor, running on an OKI HPPA board. | |
17160 | ||
17161 | @kindex target w89k | |
17162 | @item target w89k @var{dev} | |
17163 | W89K monitor, running on a Winbond HPPA board. | |
104c1213 JM |
17164 | |
17165 | @end table | |
17166 | ||
8e04817f AC |
17167 | @node Sparclet |
17168 | @subsection Tsqware Sparclet | |
104c1213 | 17169 | |
8e04817f AC |
17170 | @cindex Sparclet |
17171 | ||
17172 | @value{GDBN} enables developers to debug tasks running on | |
17173 | Sparclet targets from a Unix host. | |
17174 | @value{GDBN} uses code that runs on | |
17175 | both the Unix host and on the Sparclet target. The program | |
17176 | @code{@value{GDBP}} is installed and executed on the Unix host. | |
104c1213 | 17177 | |
8e04817f AC |
17178 | @table @code |
17179 | @item remotetimeout @var{args} | |
17180 | @kindex remotetimeout | |
17181 | @value{GDBN} supports the option @code{remotetimeout}. | |
17182 | This option is set by the user, and @var{args} represents the number of | |
17183 | seconds @value{GDBN} waits for responses. | |
104c1213 JM |
17184 | @end table |
17185 | ||
8e04817f AC |
17186 | @cindex compiling, on Sparclet |
17187 | When compiling for debugging, include the options @samp{-g} to get debug | |
17188 | information and @samp{-Ttext} to relocate the program to where you wish to | |
17189 | load it on the target. You may also want to add the options @samp{-n} or | |
17190 | @samp{-N} in order to reduce the size of the sections. Example: | |
104c1213 | 17191 | |
474c8240 | 17192 | @smallexample |
8e04817f | 17193 | sparclet-aout-gcc prog.c -Ttext 0x12010000 -g -o prog -N |
474c8240 | 17194 | @end smallexample |
104c1213 | 17195 | |
8e04817f | 17196 | You can use @code{objdump} to verify that the addresses are what you intended: |
104c1213 | 17197 | |
474c8240 | 17198 | @smallexample |
8e04817f | 17199 | sparclet-aout-objdump --headers --syms prog |
474c8240 | 17200 | @end smallexample |
104c1213 | 17201 | |
8e04817f AC |
17202 | @cindex running, on Sparclet |
17203 | Once you have set | |
17204 | your Unix execution search path to find @value{GDBN}, you are ready to | |
17205 | run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} | |
17206 | (or @code{sparclet-aout-gdb}, depending on your installation). | |
104c1213 | 17207 | |
8e04817f AC |
17208 | @value{GDBN} comes up showing the prompt: |
17209 | ||
474c8240 | 17210 | @smallexample |
8e04817f | 17211 | (gdbslet) |
474c8240 | 17212 | @end smallexample |
104c1213 JM |
17213 | |
17214 | @menu | |
8e04817f AC |
17215 | * Sparclet File:: Setting the file to debug |
17216 | * Sparclet Connection:: Connecting to Sparclet | |
17217 | * Sparclet Download:: Sparclet download | |
17218 | * Sparclet Execution:: Running and debugging | |
104c1213 JM |
17219 | @end menu |
17220 | ||
8e04817f | 17221 | @node Sparclet File |
79a6e687 | 17222 | @subsubsection Setting File to Debug |
104c1213 | 17223 | |
8e04817f | 17224 | The @value{GDBN} command @code{file} lets you choose with program to debug. |
104c1213 | 17225 | |
474c8240 | 17226 | @smallexample |
8e04817f | 17227 | (gdbslet) file prog |
474c8240 | 17228 | @end smallexample |
104c1213 | 17229 | |
8e04817f AC |
17230 | @need 1000 |
17231 | @value{GDBN} then attempts to read the symbol table of @file{prog}. | |
17232 | @value{GDBN} locates | |
17233 | the file by searching the directories listed in the command search | |
17234 | path. | |
12c27660 | 17235 | If the file was compiled with debug information (option @samp{-g}), source |
8e04817f AC |
17236 | files will be searched as well. |
17237 | @value{GDBN} locates | |
17238 | the source files by searching the directories listed in the directory search | |
79a6e687 | 17239 | path (@pxref{Environment, ,Your Program's Environment}). |
8e04817f AC |
17240 | If it fails |
17241 | to find a file, it displays a message such as: | |
104c1213 | 17242 | |
474c8240 | 17243 | @smallexample |
8e04817f | 17244 | prog: No such file or directory. |
474c8240 | 17245 | @end smallexample |
104c1213 | 17246 | |
8e04817f AC |
17247 | When this happens, add the appropriate directories to the search paths with |
17248 | the @value{GDBN} commands @code{path} and @code{dir}, and execute the | |
17249 | @code{target} command again. | |
104c1213 | 17250 | |
8e04817f AC |
17251 | @node Sparclet Connection |
17252 | @subsubsection Connecting to Sparclet | |
104c1213 | 17253 | |
8e04817f AC |
17254 | The @value{GDBN} command @code{target} lets you connect to a Sparclet target. |
17255 | To connect to a target on serial port ``@code{ttya}'', type: | |
104c1213 | 17256 | |
474c8240 | 17257 | @smallexample |
8e04817f AC |
17258 | (gdbslet) target sparclet /dev/ttya |
17259 | Remote target sparclet connected to /dev/ttya | |
17260 | main () at ../prog.c:3 | |
474c8240 | 17261 | @end smallexample |
104c1213 | 17262 | |
8e04817f AC |
17263 | @need 750 |
17264 | @value{GDBN} displays messages like these: | |
104c1213 | 17265 | |
474c8240 | 17266 | @smallexample |
8e04817f | 17267 | Connected to ttya. |
474c8240 | 17268 | @end smallexample |
104c1213 | 17269 | |
8e04817f | 17270 | @node Sparclet Download |
79a6e687 | 17271 | @subsubsection Sparclet Download |
104c1213 | 17272 | |
8e04817f AC |
17273 | @cindex download to Sparclet |
17274 | Once connected to the Sparclet target, | |
17275 | you can use the @value{GDBN} | |
17276 | @code{load} command to download the file from the host to the target. | |
17277 | The file name and load offset should be given as arguments to the @code{load} | |
17278 | command. | |
17279 | Since the file format is aout, the program must be loaded to the starting | |
17280 | address. You can use @code{objdump} to find out what this value is. The load | |
17281 | offset is an offset which is added to the VMA (virtual memory address) | |
17282 | of each of the file's sections. | |
17283 | For instance, if the program | |
17284 | @file{prog} was linked to text address 0x1201000, with data at 0x12010160 | |
17285 | and bss at 0x12010170, in @value{GDBN}, type: | |
104c1213 | 17286 | |
474c8240 | 17287 | @smallexample |
8e04817f AC |
17288 | (gdbslet) load prog 0x12010000 |
17289 | Loading section .text, size 0xdb0 vma 0x12010000 | |
474c8240 | 17290 | @end smallexample |
104c1213 | 17291 | |
8e04817f AC |
17292 | If the code is loaded at a different address then what the program was linked |
17293 | to, you may need to use the @code{section} and @code{add-symbol-file} commands | |
17294 | to tell @value{GDBN} where to map the symbol table. | |
17295 | ||
17296 | @node Sparclet Execution | |
79a6e687 | 17297 | @subsubsection Running and Debugging |
8e04817f AC |
17298 | |
17299 | @cindex running and debugging Sparclet programs | |
17300 | You can now begin debugging the task using @value{GDBN}'s execution control | |
17301 | commands, @code{b}, @code{step}, @code{run}, etc. See the @value{GDBN} | |
17302 | manual for the list of commands. | |
17303 | ||
474c8240 | 17304 | @smallexample |
8e04817f AC |
17305 | (gdbslet) b main |
17306 | Breakpoint 1 at 0x12010000: file prog.c, line 3. | |
17307 | (gdbslet) run | |
17308 | Starting program: prog | |
17309 | Breakpoint 1, main (argc=1, argv=0xeffff21c) at prog.c:3 | |
17310 | 3 char *symarg = 0; | |
17311 | (gdbslet) step | |
17312 | 4 char *execarg = "hello!"; | |
17313 | (gdbslet) | |
474c8240 | 17314 | @end smallexample |
8e04817f AC |
17315 | |
17316 | @node Sparclite | |
17317 | @subsection Fujitsu Sparclite | |
104c1213 JM |
17318 | |
17319 | @table @code | |
17320 | ||
8e04817f AC |
17321 | @kindex target sparclite |
17322 | @item target sparclite @var{dev} | |
17323 | Fujitsu sparclite boards, used only for the purpose of loading. | |
17324 | You must use an additional command to debug the program. | |
17325 | For example: target remote @var{dev} using @value{GDBN} standard | |
17326 | remote protocol. | |
104c1213 JM |
17327 | |
17328 | @end table | |
17329 | ||
8e04817f AC |
17330 | @node Z8000 |
17331 | @subsection Zilog Z8000 | |
104c1213 | 17332 | |
8e04817f AC |
17333 | @cindex Z8000 |
17334 | @cindex simulator, Z8000 | |
17335 | @cindex Zilog Z8000 simulator | |
104c1213 | 17336 | |
8e04817f AC |
17337 | When configured for debugging Zilog Z8000 targets, @value{GDBN} includes |
17338 | a Z8000 simulator. | |
17339 | ||
17340 | For the Z8000 family, @samp{target sim} simulates either the Z8002 (the | |
17341 | unsegmented variant of the Z8000 architecture) or the Z8001 (the | |
17342 | segmented variant). The simulator recognizes which architecture is | |
17343 | appropriate by inspecting the object code. | |
104c1213 | 17344 | |
8e04817f AC |
17345 | @table @code |
17346 | @item target sim @var{args} | |
17347 | @kindex sim | |
17348 | @kindex target sim@r{, with Z8000} | |
17349 | Debug programs on a simulated CPU. If the simulator supports setup | |
17350 | options, specify them via @var{args}. | |
104c1213 JM |
17351 | @end table |
17352 | ||
8e04817f AC |
17353 | @noindent |
17354 | After specifying this target, you can debug programs for the simulated | |
17355 | CPU in the same style as programs for your host computer; use the | |
17356 | @code{file} command to load a new program image, the @code{run} command | |
17357 | to run your program, and so on. | |
17358 | ||
17359 | As well as making available all the usual machine registers | |
17360 | (@pxref{Registers, ,Registers}), the Z8000 simulator provides three | |
17361 | additional items of information as specially named registers: | |
104c1213 JM |
17362 | |
17363 | @table @code | |
17364 | ||
8e04817f AC |
17365 | @item cycles |
17366 | Counts clock-ticks in the simulator. | |
104c1213 | 17367 | |
8e04817f AC |
17368 | @item insts |
17369 | Counts instructions run in the simulator. | |
104c1213 | 17370 | |
8e04817f AC |
17371 | @item time |
17372 | Execution time in 60ths of a second. | |
104c1213 | 17373 | |
8e04817f | 17374 | @end table |
104c1213 | 17375 | |
8e04817f AC |
17376 | You can refer to these values in @value{GDBN} expressions with the usual |
17377 | conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a | |
17378 | conditional breakpoint that suspends only after at least 5000 | |
17379 | simulated clock ticks. | |
104c1213 | 17380 | |
a64548ea EZ |
17381 | @node AVR |
17382 | @subsection Atmel AVR | |
17383 | @cindex AVR | |
17384 | ||
17385 | When configured for debugging the Atmel AVR, @value{GDBN} supports the | |
17386 | following AVR-specific commands: | |
17387 | ||
17388 | @table @code | |
17389 | @item info io_registers | |
17390 | @kindex info io_registers@r{, AVR} | |
17391 | @cindex I/O registers (Atmel AVR) | |
17392 | This command displays information about the AVR I/O registers. For | |
17393 | each register, @value{GDBN} prints its number and value. | |
17394 | @end table | |
17395 | ||
17396 | @node CRIS | |
17397 | @subsection CRIS | |
17398 | @cindex CRIS | |
17399 | ||
17400 | When configured for debugging CRIS, @value{GDBN} provides the | |
17401 | following CRIS-specific commands: | |
17402 | ||
17403 | @table @code | |
17404 | @item set cris-version @var{ver} | |
17405 | @cindex CRIS version | |
e22e55c9 OF |
17406 | Set the current CRIS version to @var{ver}, either @samp{10} or @samp{32}. |
17407 | The CRIS version affects register names and sizes. This command is useful in | |
17408 | case autodetection of the CRIS version fails. | |
a64548ea EZ |
17409 | |
17410 | @item show cris-version | |
17411 | Show the current CRIS version. | |
17412 | ||
17413 | @item set cris-dwarf2-cfi | |
17414 | @cindex DWARF-2 CFI and CRIS | |
e22e55c9 OF |
17415 | Set the usage of DWARF-2 CFI for CRIS debugging. The default is @samp{on}. |
17416 | Change to @samp{off} when using @code{gcc-cris} whose version is below | |
17417 | @code{R59}. | |
a64548ea EZ |
17418 | |
17419 | @item show cris-dwarf2-cfi | |
17420 | Show the current state of using DWARF-2 CFI. | |
e22e55c9 OF |
17421 | |
17422 | @item set cris-mode @var{mode} | |
17423 | @cindex CRIS mode | |
17424 | Set the current CRIS mode to @var{mode}. It should only be changed when | |
17425 | debugging in guru mode, in which case it should be set to | |
17426 | @samp{guru} (the default is @samp{normal}). | |
17427 | ||
17428 | @item show cris-mode | |
17429 | Show the current CRIS mode. | |
a64548ea EZ |
17430 | @end table |
17431 | ||
17432 | @node Super-H | |
17433 | @subsection Renesas Super-H | |
17434 | @cindex Super-H | |
17435 | ||
17436 | For the Renesas Super-H processor, @value{GDBN} provides these | |
17437 | commands: | |
17438 | ||
17439 | @table @code | |
17440 | @item regs | |
17441 | @kindex regs@r{, Super-H} | |
17442 | Show the values of all Super-H registers. | |
c055b101 CV |
17443 | |
17444 | @item set sh calling-convention @var{convention} | |
17445 | @kindex set sh calling-convention | |
17446 | Set the calling-convention used when calling functions from @value{GDBN}. | |
17447 | Allowed values are @samp{gcc}, which is the default setting, and @samp{renesas}. | |
17448 | With the @samp{gcc} setting, functions are called using the @value{NGCC} calling | |
17449 | convention. If the DWARF-2 information of the called function specifies | |
17450 | that the function follows the Renesas calling convention, the function | |
17451 | is called using the Renesas calling convention. If the calling convention | |
17452 | is set to @samp{renesas}, the Renesas calling convention is always used, | |
17453 | regardless of the DWARF-2 information. This can be used to override the | |
17454 | default of @samp{gcc} if debug information is missing, or the compiler | |
17455 | does not emit the DWARF-2 calling convention entry for a function. | |
17456 | ||
17457 | @item show sh calling-convention | |
17458 | @kindex show sh calling-convention | |
17459 | Show the current calling convention setting. | |
17460 | ||
a64548ea EZ |
17461 | @end table |
17462 | ||
17463 | ||
8e04817f AC |
17464 | @node Architectures |
17465 | @section Architectures | |
104c1213 | 17466 | |
8e04817f AC |
17467 | This section describes characteristics of architectures that affect |
17468 | all uses of @value{GDBN} with the architecture, both native and cross. | |
104c1213 | 17469 | |
8e04817f | 17470 | @menu |
9c16f35a | 17471 | * i386:: |
8e04817f AC |
17472 | * A29K:: |
17473 | * Alpha:: | |
17474 | * MIPS:: | |
a64548ea | 17475 | * HPPA:: HP PA architecture |
23d964e7 | 17476 | * SPU:: Cell Broadband Engine SPU architecture |
4acd40f3 | 17477 | * PowerPC:: |
8e04817f | 17478 | @end menu |
104c1213 | 17479 | |
9c16f35a | 17480 | @node i386 |
db2e3e2e | 17481 | @subsection x86 Architecture-specific Issues |
9c16f35a EZ |
17482 | |
17483 | @table @code | |
17484 | @item set struct-convention @var{mode} | |
17485 | @kindex set struct-convention | |
17486 | @cindex struct return convention | |
17487 | @cindex struct/union returned in registers | |
17488 | Set the convention used by the inferior to return @code{struct}s and | |
17489 | @code{union}s from functions to @var{mode}. Possible values of | |
17490 | @var{mode} are @code{"pcc"}, @code{"reg"}, and @code{"default"} (the | |
17491 | default). @code{"default"} or @code{"pcc"} means that @code{struct}s | |
17492 | are returned on the stack, while @code{"reg"} means that a | |
17493 | @code{struct} or a @code{union} whose size is 1, 2, 4, or 8 bytes will | |
17494 | be returned in a register. | |
17495 | ||
17496 | @item show struct-convention | |
17497 | @kindex show struct-convention | |
17498 | Show the current setting of the convention to return @code{struct}s | |
17499 | from functions. | |
17500 | @end table | |
17501 | ||
8e04817f AC |
17502 | @node A29K |
17503 | @subsection A29K | |
104c1213 JM |
17504 | |
17505 | @table @code | |
104c1213 | 17506 | |
8e04817f AC |
17507 | @kindex set rstack_high_address |
17508 | @cindex AMD 29K register stack | |
17509 | @cindex register stack, AMD29K | |
17510 | @item set rstack_high_address @var{address} | |
17511 | On AMD 29000 family processors, registers are saved in a separate | |
17512 | @dfn{register stack}. There is no way for @value{GDBN} to determine the | |
17513 | extent of this stack. Normally, @value{GDBN} just assumes that the | |
17514 | stack is ``large enough''. This may result in @value{GDBN} referencing | |
17515 | memory locations that do not exist. If necessary, you can get around | |
17516 | this problem by specifying the ending address of the register stack with | |
17517 | the @code{set rstack_high_address} command. The argument should be an | |
17518 | address, which you probably want to precede with @samp{0x} to specify in | |
17519 | hexadecimal. | |
104c1213 | 17520 | |
8e04817f AC |
17521 | @kindex show rstack_high_address |
17522 | @item show rstack_high_address | |
17523 | Display the current limit of the register stack, on AMD 29000 family | |
17524 | processors. | |
104c1213 | 17525 | |
8e04817f | 17526 | @end table |
104c1213 | 17527 | |
8e04817f AC |
17528 | @node Alpha |
17529 | @subsection Alpha | |
104c1213 | 17530 | |
8e04817f | 17531 | See the following section. |
104c1213 | 17532 | |
8e04817f AC |
17533 | @node MIPS |
17534 | @subsection MIPS | |
104c1213 | 17535 | |
8e04817f AC |
17536 | @cindex stack on Alpha |
17537 | @cindex stack on MIPS | |
17538 | @cindex Alpha stack | |
17539 | @cindex MIPS stack | |
17540 | Alpha- and MIPS-based computers use an unusual stack frame, which | |
17541 | sometimes requires @value{GDBN} to search backward in the object code to | |
17542 | find the beginning of a function. | |
104c1213 | 17543 | |
8e04817f AC |
17544 | @cindex response time, MIPS debugging |
17545 | To improve response time (especially for embedded applications, where | |
17546 | @value{GDBN} may be restricted to a slow serial line for this search) | |
17547 | you may want to limit the size of this search, using one of these | |
17548 | commands: | |
104c1213 | 17549 | |
8e04817f AC |
17550 | @table @code |
17551 | @cindex @code{heuristic-fence-post} (Alpha, MIPS) | |
17552 | @item set heuristic-fence-post @var{limit} | |
17553 | Restrict @value{GDBN} to examining at most @var{limit} bytes in its | |
17554 | search for the beginning of a function. A value of @var{0} (the | |
17555 | default) means there is no limit. However, except for @var{0}, the | |
17556 | larger the limit the more bytes @code{heuristic-fence-post} must search | |
e2f4edfd EZ |
17557 | and therefore the longer it takes to run. You should only need to use |
17558 | this command when debugging a stripped executable. | |
104c1213 | 17559 | |
8e04817f AC |
17560 | @item show heuristic-fence-post |
17561 | Display the current limit. | |
17562 | @end table | |
104c1213 JM |
17563 | |
17564 | @noindent | |
8e04817f AC |
17565 | These commands are available @emph{only} when @value{GDBN} is configured |
17566 | for debugging programs on Alpha or MIPS processors. | |
104c1213 | 17567 | |
a64548ea EZ |
17568 | Several MIPS-specific commands are available when debugging MIPS |
17569 | programs: | |
17570 | ||
17571 | @table @code | |
a64548ea EZ |
17572 | @item set mips abi @var{arg} |
17573 | @kindex set mips abi | |
17574 | @cindex set ABI for MIPS | |
17575 | Tell @value{GDBN} which MIPS ABI is used by the inferior. Possible | |
17576 | values of @var{arg} are: | |
17577 | ||
17578 | @table @samp | |
17579 | @item auto | |
17580 | The default ABI associated with the current binary (this is the | |
17581 | default). | |
17582 | @item o32 | |
17583 | @item o64 | |
17584 | @item n32 | |
17585 | @item n64 | |
17586 | @item eabi32 | |
17587 | @item eabi64 | |
17588 | @item auto | |
17589 | @end table | |
17590 | ||
17591 | @item show mips abi | |
17592 | @kindex show mips abi | |
17593 | Show the MIPS ABI used by @value{GDBN} to debug the inferior. | |
17594 | ||
17595 | @item set mipsfpu | |
17596 | @itemx show mipsfpu | |
17597 | @xref{MIPS Embedded, set mipsfpu}. | |
17598 | ||
17599 | @item set mips mask-address @var{arg} | |
17600 | @kindex set mips mask-address | |
17601 | @cindex MIPS addresses, masking | |
17602 | This command determines whether the most-significant 32 bits of 64-bit | |
17603 | MIPS addresses are masked off. The argument @var{arg} can be | |
17604 | @samp{on}, @samp{off}, or @samp{auto}. The latter is the default | |
17605 | setting, which lets @value{GDBN} determine the correct value. | |
17606 | ||
17607 | @item show mips mask-address | |
17608 | @kindex show mips mask-address | |
17609 | Show whether the upper 32 bits of MIPS addresses are masked off or | |
17610 | not. | |
17611 | ||
17612 | @item set remote-mips64-transfers-32bit-regs | |
17613 | @kindex set remote-mips64-transfers-32bit-regs | |
17614 | This command controls compatibility with 64-bit MIPS targets that | |
17615 | transfer data in 32-bit quantities. If you have an old MIPS 64 target | |
17616 | that transfers 32 bits for some registers, like @sc{sr} and @sc{fsr}, | |
17617 | and 64 bits for other registers, set this option to @samp{on}. | |
17618 | ||
17619 | @item show remote-mips64-transfers-32bit-regs | |
17620 | @kindex show remote-mips64-transfers-32bit-regs | |
17621 | Show the current setting of compatibility with older MIPS 64 targets. | |
17622 | ||
17623 | @item set debug mips | |
17624 | @kindex set debug mips | |
17625 | This command turns on and off debugging messages for the MIPS-specific | |
17626 | target code in @value{GDBN}. | |
17627 | ||
17628 | @item show debug mips | |
17629 | @kindex show debug mips | |
17630 | Show the current setting of MIPS debugging messages. | |
17631 | @end table | |
17632 | ||
17633 | ||
17634 | @node HPPA | |
17635 | @subsection HPPA | |
17636 | @cindex HPPA support | |
17637 | ||
d3e8051b | 17638 | When @value{GDBN} is debugging the HP PA architecture, it provides the |
a64548ea EZ |
17639 | following special commands: |
17640 | ||
17641 | @table @code | |
17642 | @item set debug hppa | |
17643 | @kindex set debug hppa | |
db2e3e2e | 17644 | This command determines whether HPPA architecture-specific debugging |
a64548ea EZ |
17645 | messages are to be displayed. |
17646 | ||
17647 | @item show debug hppa | |
17648 | Show whether HPPA debugging messages are displayed. | |
17649 | ||
17650 | @item maint print unwind @var{address} | |
17651 | @kindex maint print unwind@r{, HPPA} | |
17652 | This command displays the contents of the unwind table entry at the | |
17653 | given @var{address}. | |
17654 | ||
17655 | @end table | |
17656 | ||
104c1213 | 17657 | |
23d964e7 UW |
17658 | @node SPU |
17659 | @subsection Cell Broadband Engine SPU architecture | |
17660 | @cindex Cell Broadband Engine | |
17661 | @cindex SPU | |
17662 | ||
17663 | When @value{GDBN} is debugging the Cell Broadband Engine SPU architecture, | |
17664 | it provides the following special commands: | |
17665 | ||
17666 | @table @code | |
17667 | @item info spu event | |
17668 | @kindex info spu | |
17669 | Display SPU event facility status. Shows current event mask | |
17670 | and pending event status. | |
17671 | ||
17672 | @item info spu signal | |
17673 | Display SPU signal notification facility status. Shows pending | |
17674 | signal-control word and signal notification mode of both signal | |
17675 | notification channels. | |
17676 | ||
17677 | @item info spu mailbox | |
17678 | Display SPU mailbox facility status. Shows all pending entries, | |
17679 | in order of processing, in each of the SPU Write Outbound, | |
17680 | SPU Write Outbound Interrupt, and SPU Read Inbound mailboxes. | |
17681 | ||
17682 | @item info spu dma | |
17683 | Display MFC DMA status. Shows all pending commands in the MFC | |
17684 | DMA queue. For each entry, opcode, tag, class IDs, effective | |
17685 | and local store addresses and transfer size are shown. | |
17686 | ||
17687 | @item info spu proxydma | |
17688 | Display MFC Proxy-DMA status. Shows all pending commands in the MFC | |
17689 | Proxy-DMA queue. For each entry, opcode, tag, class IDs, effective | |
17690 | and local store addresses and transfer size are shown. | |
17691 | ||
17692 | @end table | |
17693 | ||
3285f3fe UW |
17694 | When @value{GDBN} is debugging a combined PowerPC/SPU application |
17695 | on the Cell Broadband Engine, it provides in addition the following | |
17696 | special commands: | |
17697 | ||
17698 | @table @code | |
17699 | @item set spu stop-on-load @var{arg} | |
17700 | @kindex set spu | |
17701 | Set whether to stop for new SPE threads. When set to @code{on}, @value{GDBN} | |
17702 | will give control to the user when a new SPE thread enters its @code{main} | |
17703 | function. The default is @code{off}. | |
17704 | ||
17705 | @item show spu stop-on-load | |
17706 | @kindex show spu | |
17707 | Show whether to stop for new SPE threads. | |
17708 | ||
ff1a52c6 UW |
17709 | @item set spu auto-flush-cache @var{arg} |
17710 | Set whether to automatically flush the software-managed cache. When set to | |
17711 | @code{on}, @value{GDBN} will automatically cause the SPE software-managed | |
17712 | cache to be flushed whenever SPE execution stops. This provides a consistent | |
17713 | view of PowerPC memory that is accessed via the cache. If an application | |
17714 | does not use the software-managed cache, this option has no effect. | |
17715 | ||
17716 | @item show spu auto-flush-cache | |
17717 | Show whether to automatically flush the software-managed cache. | |
17718 | ||
3285f3fe UW |
17719 | @end table |
17720 | ||
4acd40f3 TJB |
17721 | @node PowerPC |
17722 | @subsection PowerPC | |
17723 | @cindex PowerPC architecture | |
17724 | ||
17725 | When @value{GDBN} is debugging the PowerPC architecture, it provides a set of | |
17726 | pseudo-registers to enable inspection of 128-bit wide Decimal Floating Point | |
17727 | numbers stored in the floating point registers. These values must be stored | |
17728 | in two consecutive registers, always starting at an even register like | |
17729 | @code{f0} or @code{f2}. | |
17730 | ||
17731 | The pseudo-registers go from @code{$dl0} through @code{$dl15}, and are formed | |
17732 | by joining the even/odd register pairs @code{f0} and @code{f1} for @code{$dl0}, | |
17733 | @code{f2} and @code{f3} for @code{$dl1} and so on. | |
17734 | ||
aeac0ff9 | 17735 | For POWER7 processors, @value{GDBN} provides a set of pseudo-registers, the 64-bit |
677c5bb1 LM |
17736 | wide Extended Floating Point Registers (@samp{f32} through @samp{f63}). |
17737 | ||
23d964e7 | 17738 | |
8e04817f AC |
17739 | @node Controlling GDB |
17740 | @chapter Controlling @value{GDBN} | |
17741 | ||
17742 | You can alter the way @value{GDBN} interacts with you by using the | |
17743 | @code{set} command. For commands controlling how @value{GDBN} displays | |
79a6e687 | 17744 | data, see @ref{Print Settings, ,Print Settings}. Other settings are |
8e04817f AC |
17745 | described here. |
17746 | ||
17747 | @menu | |
17748 | * Prompt:: Prompt | |
17749 | * Editing:: Command editing | |
d620b259 | 17750 | * Command History:: Command history |
8e04817f AC |
17751 | * Screen Size:: Screen size |
17752 | * Numbers:: Numbers | |
1e698235 | 17753 | * ABI:: Configuring the current ABI |
8e04817f AC |
17754 | * Messages/Warnings:: Optional warnings and messages |
17755 | * Debugging Output:: Optional messages about internal happenings | |
14fb1bac | 17756 | * Other Misc Settings:: Other Miscellaneous Settings |
8e04817f AC |
17757 | @end menu |
17758 | ||
17759 | @node Prompt | |
17760 | @section Prompt | |
104c1213 | 17761 | |
8e04817f | 17762 | @cindex prompt |
104c1213 | 17763 | |
8e04817f AC |
17764 | @value{GDBN} indicates its readiness to read a command by printing a string |
17765 | called the @dfn{prompt}. This string is normally @samp{(@value{GDBP})}. You | |
17766 | can change the prompt string with the @code{set prompt} command. For | |
17767 | instance, when debugging @value{GDBN} with @value{GDBN}, it is useful to change | |
17768 | the prompt in one of the @value{GDBN} sessions so that you can always tell | |
17769 | which one you are talking to. | |
104c1213 | 17770 | |
8e04817f AC |
17771 | @emph{Note:} @code{set prompt} does not add a space for you after the |
17772 | prompt you set. This allows you to set a prompt which ends in a space | |
17773 | or a prompt that does not. | |
104c1213 | 17774 | |
8e04817f AC |
17775 | @table @code |
17776 | @kindex set prompt | |
17777 | @item set prompt @var{newprompt} | |
17778 | Directs @value{GDBN} to use @var{newprompt} as its prompt string henceforth. | |
104c1213 | 17779 | |
8e04817f AC |
17780 | @kindex show prompt |
17781 | @item show prompt | |
17782 | Prints a line of the form: @samp{Gdb's prompt is: @var{your-prompt}} | |
104c1213 JM |
17783 | @end table |
17784 | ||
8e04817f | 17785 | @node Editing |
79a6e687 | 17786 | @section Command Editing |
8e04817f AC |
17787 | @cindex readline |
17788 | @cindex command line editing | |
104c1213 | 17789 | |
703663ab | 17790 | @value{GDBN} reads its input commands via the @dfn{Readline} interface. This |
8e04817f AC |
17791 | @sc{gnu} library provides consistent behavior for programs which provide a |
17792 | command line interface to the user. Advantages are @sc{gnu} Emacs-style | |
17793 | or @dfn{vi}-style inline editing of commands, @code{csh}-like history | |
17794 | substitution, and a storage and recall of command history across | |
17795 | debugging sessions. | |
104c1213 | 17796 | |
8e04817f AC |
17797 | You may control the behavior of command line editing in @value{GDBN} with the |
17798 | command @code{set}. | |
104c1213 | 17799 | |
8e04817f AC |
17800 | @table @code |
17801 | @kindex set editing | |
17802 | @cindex editing | |
17803 | @item set editing | |
17804 | @itemx set editing on | |
17805 | Enable command line editing (enabled by default). | |
104c1213 | 17806 | |
8e04817f AC |
17807 | @item set editing off |
17808 | Disable command line editing. | |
104c1213 | 17809 | |
8e04817f AC |
17810 | @kindex show editing |
17811 | @item show editing | |
17812 | Show whether command line editing is enabled. | |
104c1213 JM |
17813 | @end table |
17814 | ||
703663ab EZ |
17815 | @xref{Command Line Editing}, for more details about the Readline |
17816 | interface. Users unfamiliar with @sc{gnu} Emacs or @code{vi} are | |
17817 | encouraged to read that chapter. | |
17818 | ||
d620b259 | 17819 | @node Command History |
79a6e687 | 17820 | @section Command History |
703663ab | 17821 | @cindex command history |
8e04817f AC |
17822 | |
17823 | @value{GDBN} can keep track of the commands you type during your | |
17824 | debugging sessions, so that you can be certain of precisely what | |
17825 | happened. Use these commands to manage the @value{GDBN} command | |
17826 | history facility. | |
104c1213 | 17827 | |
703663ab EZ |
17828 | @value{GDBN} uses the @sc{gnu} History library, a part of the Readline |
17829 | package, to provide the history facility. @xref{Using History | |
17830 | Interactively}, for the detailed description of the History library. | |
17831 | ||
d620b259 | 17832 | To issue a command to @value{GDBN} without affecting certain aspects of |
9e6c4bd5 NR |
17833 | the state which is seen by users, prefix it with @samp{server } |
17834 | (@pxref{Server Prefix}). This | |
d620b259 NR |
17835 | means that this command will not affect the command history, nor will it |
17836 | affect @value{GDBN}'s notion of which command to repeat if @key{RET} is | |
17837 | pressed on a line by itself. | |
17838 | ||
17839 | @cindex @code{server}, command prefix | |
17840 | The server prefix does not affect the recording of values into the value | |
17841 | history; to print a value without recording it into the value history, | |
17842 | use the @code{output} command instead of the @code{print} command. | |
17843 | ||
703663ab EZ |
17844 | Here is the description of @value{GDBN} commands related to command |
17845 | history. | |
17846 | ||
104c1213 | 17847 | @table @code |
8e04817f AC |
17848 | @cindex history substitution |
17849 | @cindex history file | |
17850 | @kindex set history filename | |
4644b6e3 | 17851 | @cindex @env{GDBHISTFILE}, environment variable |
8e04817f AC |
17852 | @item set history filename @var{fname} |
17853 | Set the name of the @value{GDBN} command history file to @var{fname}. | |
17854 | This is the file where @value{GDBN} reads an initial command history | |
17855 | list, and where it writes the command history from this session when it | |
17856 | exits. You can access this list through history expansion or through | |
17857 | the history command editing characters listed below. This file defaults | |
17858 | to the value of the environment variable @code{GDBHISTFILE}, or to | |
17859 | @file{./.gdb_history} (@file{./_gdb_history} on MS-DOS) if this variable | |
17860 | is not set. | |
104c1213 | 17861 | |
9c16f35a EZ |
17862 | @cindex save command history |
17863 | @kindex set history save | |
8e04817f AC |
17864 | @item set history save |
17865 | @itemx set history save on | |
17866 | Record command history in a file, whose name may be specified with the | |
17867 | @code{set history filename} command. By default, this option is disabled. | |
104c1213 | 17868 | |
8e04817f AC |
17869 | @item set history save off |
17870 | Stop recording command history in a file. | |
104c1213 | 17871 | |
8e04817f | 17872 | @cindex history size |
9c16f35a | 17873 | @kindex set history size |
6fc08d32 | 17874 | @cindex @env{HISTSIZE}, environment variable |
8e04817f AC |
17875 | @item set history size @var{size} |
17876 | Set the number of commands which @value{GDBN} keeps in its history list. | |
17877 | This defaults to the value of the environment variable | |
17878 | @code{HISTSIZE}, or to 256 if this variable is not set. | |
104c1213 JM |
17879 | @end table |
17880 | ||
8e04817f | 17881 | History expansion assigns special meaning to the character @kbd{!}. |
703663ab | 17882 | @xref{Event Designators}, for more details. |
8e04817f | 17883 | |
703663ab | 17884 | @cindex history expansion, turn on/off |
8e04817f AC |
17885 | Since @kbd{!} is also the logical not operator in C, history expansion |
17886 | is off by default. If you decide to enable history expansion with the | |
17887 | @code{set history expansion on} command, you may sometimes need to | |
17888 | follow @kbd{!} (when it is used as logical not, in an expression) with | |
17889 | a space or a tab to prevent it from being expanded. The readline | |
17890 | history facilities do not attempt substitution on the strings | |
17891 | @kbd{!=} and @kbd{!(}, even when history expansion is enabled. | |
17892 | ||
17893 | The commands to control history expansion are: | |
104c1213 JM |
17894 | |
17895 | @table @code | |
8e04817f AC |
17896 | @item set history expansion on |
17897 | @itemx set history expansion | |
703663ab | 17898 | @kindex set history expansion |
8e04817f | 17899 | Enable history expansion. History expansion is off by default. |
104c1213 | 17900 | |
8e04817f AC |
17901 | @item set history expansion off |
17902 | Disable history expansion. | |
104c1213 | 17903 | |
8e04817f AC |
17904 | @c @group |
17905 | @kindex show history | |
17906 | @item show history | |
17907 | @itemx show history filename | |
17908 | @itemx show history save | |
17909 | @itemx show history size | |
17910 | @itemx show history expansion | |
17911 | These commands display the state of the @value{GDBN} history parameters. | |
17912 | @code{show history} by itself displays all four states. | |
17913 | @c @end group | |
17914 | @end table | |
17915 | ||
17916 | @table @code | |
9c16f35a EZ |
17917 | @kindex show commands |
17918 | @cindex show last commands | |
17919 | @cindex display command history | |
8e04817f AC |
17920 | @item show commands |
17921 | Display the last ten commands in the command history. | |
104c1213 | 17922 | |
8e04817f AC |
17923 | @item show commands @var{n} |
17924 | Print ten commands centered on command number @var{n}. | |
17925 | ||
17926 | @item show commands + | |
17927 | Print ten commands just after the commands last printed. | |
104c1213 JM |
17928 | @end table |
17929 | ||
8e04817f | 17930 | @node Screen Size |
79a6e687 | 17931 | @section Screen Size |
8e04817f AC |
17932 | @cindex size of screen |
17933 | @cindex pauses in output | |
104c1213 | 17934 | |
8e04817f AC |
17935 | Certain commands to @value{GDBN} may produce large amounts of |
17936 | information output to the screen. To help you read all of it, | |
17937 | @value{GDBN} pauses and asks you for input at the end of each page of | |
17938 | output. Type @key{RET} when you want to continue the output, or @kbd{q} | |
17939 | to discard the remaining output. Also, the screen width setting | |
17940 | determines when to wrap lines of output. Depending on what is being | |
17941 | printed, @value{GDBN} tries to break the line at a readable place, | |
17942 | rather than simply letting it overflow onto the following line. | |
17943 | ||
17944 | Normally @value{GDBN} knows the size of the screen from the terminal | |
17945 | driver software. For example, on Unix @value{GDBN} uses the termcap data base | |
17946 | together with the value of the @code{TERM} environment variable and the | |
17947 | @code{stty rows} and @code{stty cols} settings. If this is not correct, | |
17948 | you can override it with the @code{set height} and @code{set | |
17949 | width} commands: | |
17950 | ||
17951 | @table @code | |
17952 | @kindex set height | |
17953 | @kindex set width | |
17954 | @kindex show width | |
17955 | @kindex show height | |
17956 | @item set height @var{lpp} | |
17957 | @itemx show height | |
17958 | @itemx set width @var{cpl} | |
17959 | @itemx show width | |
17960 | These @code{set} commands specify a screen height of @var{lpp} lines and | |
17961 | a screen width of @var{cpl} characters. The associated @code{show} | |
17962 | commands display the current settings. | |
104c1213 | 17963 | |
8e04817f AC |
17964 | If you specify a height of zero lines, @value{GDBN} does not pause during |
17965 | output no matter how long the output is. This is useful if output is to a | |
17966 | file or to an editor buffer. | |
104c1213 | 17967 | |
8e04817f AC |
17968 | Likewise, you can specify @samp{set width 0} to prevent @value{GDBN} |
17969 | from wrapping its output. | |
9c16f35a EZ |
17970 | |
17971 | @item set pagination on | |
17972 | @itemx set pagination off | |
17973 | @kindex set pagination | |
17974 | Turn the output pagination on or off; the default is on. Turning | |
17975 | pagination off is the alternative to @code{set height 0}. | |
17976 | ||
17977 | @item show pagination | |
17978 | @kindex show pagination | |
17979 | Show the current pagination mode. | |
104c1213 JM |
17980 | @end table |
17981 | ||
8e04817f AC |
17982 | @node Numbers |
17983 | @section Numbers | |
17984 | @cindex number representation | |
17985 | @cindex entering numbers | |
104c1213 | 17986 | |
8e04817f AC |
17987 | You can always enter numbers in octal, decimal, or hexadecimal in |
17988 | @value{GDBN} by the usual conventions: octal numbers begin with | |
17989 | @samp{0}, decimal numbers end with @samp{.}, and hexadecimal numbers | |
eb2dae08 EZ |
17990 | begin with @samp{0x}. Numbers that neither begin with @samp{0} or |
17991 | @samp{0x}, nor end with a @samp{.} are, by default, entered in base | |
17992 | 10; likewise, the default display for numbers---when no particular | |
17993 | format is specified---is base 10. You can change the default base for | |
17994 | both input and output with the commands described below. | |
104c1213 | 17995 | |
8e04817f AC |
17996 | @table @code |
17997 | @kindex set input-radix | |
17998 | @item set input-radix @var{base} | |
17999 | Set the default base for numeric input. Supported choices | |
18000 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
eb2dae08 | 18001 | specified either unambiguously or using the current input radix; for |
8e04817f | 18002 | example, any of |
104c1213 | 18003 | |
8e04817f | 18004 | @smallexample |
9c16f35a EZ |
18005 | set input-radix 012 |
18006 | set input-radix 10. | |
18007 | set input-radix 0xa | |
8e04817f | 18008 | @end smallexample |
104c1213 | 18009 | |
8e04817f | 18010 | @noindent |
9c16f35a | 18011 | sets the input base to decimal. On the other hand, @samp{set input-radix 10} |
eb2dae08 EZ |
18012 | leaves the input radix unchanged, no matter what it was, since |
18013 | @samp{10}, being without any leading or trailing signs of its base, is | |
18014 | interpreted in the current radix. Thus, if the current radix is 16, | |
18015 | @samp{10} is interpreted in hex, i.e.@: as 16 decimal, which doesn't | |
18016 | change the radix. | |
104c1213 | 18017 | |
8e04817f AC |
18018 | @kindex set output-radix |
18019 | @item set output-radix @var{base} | |
18020 | Set the default base for numeric display. Supported choices | |
18021 | for @var{base} are decimal 8, 10, or 16. @var{base} must itself be | |
eb2dae08 | 18022 | specified either unambiguously or using the current input radix. |
104c1213 | 18023 | |
8e04817f AC |
18024 | @kindex show input-radix |
18025 | @item show input-radix | |
18026 | Display the current default base for numeric input. | |
104c1213 | 18027 | |
8e04817f AC |
18028 | @kindex show output-radix |
18029 | @item show output-radix | |
18030 | Display the current default base for numeric display. | |
9c16f35a EZ |
18031 | |
18032 | @item set radix @r{[}@var{base}@r{]} | |
18033 | @itemx show radix | |
18034 | @kindex set radix | |
18035 | @kindex show radix | |
18036 | These commands set and show the default base for both input and output | |
18037 | of numbers. @code{set radix} sets the radix of input and output to | |
18038 | the same base; without an argument, it resets the radix back to its | |
18039 | default value of 10. | |
18040 | ||
8e04817f | 18041 | @end table |
104c1213 | 18042 | |
1e698235 | 18043 | @node ABI |
79a6e687 | 18044 | @section Configuring the Current ABI |
1e698235 DJ |
18045 | |
18046 | @value{GDBN} can determine the @dfn{ABI} (Application Binary Interface) of your | |
18047 | application automatically. However, sometimes you need to override its | |
18048 | conclusions. Use these commands to manage @value{GDBN}'s view of the | |
18049 | current ABI. | |
18050 | ||
98b45e30 DJ |
18051 | @cindex OS ABI |
18052 | @kindex set osabi | |
b4e9345d | 18053 | @kindex show osabi |
98b45e30 DJ |
18054 | |
18055 | One @value{GDBN} configuration can debug binaries for multiple operating | |
b383017d | 18056 | system targets, either via remote debugging or native emulation. |
98b45e30 DJ |
18057 | @value{GDBN} will autodetect the @dfn{OS ABI} (Operating System ABI) in use, |
18058 | but you can override its conclusion using the @code{set osabi} command. | |
18059 | One example where this is useful is in debugging of binaries which use | |
18060 | an alternate C library (e.g.@: @sc{uClibc} for @sc{gnu}/Linux) which does | |
18061 | not have the same identifying marks that the standard C library for your | |
18062 | platform provides. | |
18063 | ||
18064 | @table @code | |
18065 | @item show osabi | |
18066 | Show the OS ABI currently in use. | |
18067 | ||
18068 | @item set osabi | |
18069 | With no argument, show the list of registered available OS ABI's. | |
18070 | ||
18071 | @item set osabi @var{abi} | |
18072 | Set the current OS ABI to @var{abi}. | |
18073 | @end table | |
18074 | ||
1e698235 | 18075 | @cindex float promotion |
1e698235 DJ |
18076 | |
18077 | Generally, the way that an argument of type @code{float} is passed to a | |
18078 | function depends on whether the function is prototyped. For a prototyped | |
18079 | (i.e.@: ANSI/ISO style) function, @code{float} arguments are passed unchanged, | |
18080 | according to the architecture's convention for @code{float}. For unprototyped | |
18081 | (i.e.@: K&R style) functions, @code{float} arguments are first promoted to type | |
18082 | @code{double} and then passed. | |
18083 | ||
18084 | Unfortunately, some forms of debug information do not reliably indicate whether | |
18085 | a function is prototyped. If @value{GDBN} calls a function that is not marked | |
18086 | as prototyped, it consults @kbd{set coerce-float-to-double}. | |
18087 | ||
18088 | @table @code | |
a8f24a35 | 18089 | @kindex set coerce-float-to-double |
1e698235 DJ |
18090 | @item set coerce-float-to-double |
18091 | @itemx set coerce-float-to-double on | |
18092 | Arguments of type @code{float} will be promoted to @code{double} when passed | |
18093 | to an unprototyped function. This is the default setting. | |
18094 | ||
18095 | @item set coerce-float-to-double off | |
18096 | Arguments of type @code{float} will be passed directly to unprototyped | |
18097 | functions. | |
9c16f35a EZ |
18098 | |
18099 | @kindex show coerce-float-to-double | |
18100 | @item show coerce-float-to-double | |
18101 | Show the current setting of promoting @code{float} to @code{double}. | |
1e698235 DJ |
18102 | @end table |
18103 | ||
f1212245 DJ |
18104 | @kindex set cp-abi |
18105 | @kindex show cp-abi | |
18106 | @value{GDBN} needs to know the ABI used for your program's C@t{++} | |
18107 | objects. The correct C@t{++} ABI depends on which C@t{++} compiler was | |
18108 | used to build your application. @value{GDBN} only fully supports | |
18109 | programs with a single C@t{++} ABI; if your program contains code using | |
18110 | multiple C@t{++} ABI's or if @value{GDBN} can not identify your | |
18111 | program's ABI correctly, you can tell @value{GDBN} which ABI to use. | |
18112 | Currently supported ABI's include ``gnu-v2'', for @code{g++} versions | |
18113 | before 3.0, ``gnu-v3'', for @code{g++} versions 3.0 and later, and | |
18114 | ``hpaCC'' for the HP ANSI C@t{++} compiler. Other C@t{++} compilers may | |
18115 | use the ``gnu-v2'' or ``gnu-v3'' ABI's as well. The default setting is | |
18116 | ``auto''. | |
18117 | ||
18118 | @table @code | |
18119 | @item show cp-abi | |
18120 | Show the C@t{++} ABI currently in use. | |
18121 | ||
18122 | @item set cp-abi | |
18123 | With no argument, show the list of supported C@t{++} ABI's. | |
18124 | ||
18125 | @item set cp-abi @var{abi} | |
18126 | @itemx set cp-abi auto | |
18127 | Set the current C@t{++} ABI to @var{abi}, or return to automatic detection. | |
18128 | @end table | |
18129 | ||
8e04817f | 18130 | @node Messages/Warnings |
79a6e687 | 18131 | @section Optional Warnings and Messages |
104c1213 | 18132 | |
9c16f35a EZ |
18133 | @cindex verbose operation |
18134 | @cindex optional warnings | |
8e04817f AC |
18135 | By default, @value{GDBN} is silent about its inner workings. If you are |
18136 | running on a slow machine, you may want to use the @code{set verbose} | |
18137 | command. This makes @value{GDBN} tell you when it does a lengthy | |
18138 | internal operation, so you will not think it has crashed. | |
104c1213 | 18139 | |
8e04817f AC |
18140 | Currently, the messages controlled by @code{set verbose} are those |
18141 | which announce that the symbol table for a source file is being read; | |
79a6e687 | 18142 | see @code{symbol-file} in @ref{Files, ,Commands to Specify Files}. |
104c1213 | 18143 | |
8e04817f AC |
18144 | @table @code |
18145 | @kindex set verbose | |
18146 | @item set verbose on | |
18147 | Enables @value{GDBN} output of certain informational messages. | |
104c1213 | 18148 | |
8e04817f AC |
18149 | @item set verbose off |
18150 | Disables @value{GDBN} output of certain informational messages. | |
104c1213 | 18151 | |
8e04817f AC |
18152 | @kindex show verbose |
18153 | @item show verbose | |
18154 | Displays whether @code{set verbose} is on or off. | |
18155 | @end table | |
104c1213 | 18156 | |
8e04817f AC |
18157 | By default, if @value{GDBN} encounters bugs in the symbol table of an |
18158 | object file, it is silent; but if you are debugging a compiler, you may | |
79a6e687 BW |
18159 | find this information useful (@pxref{Symbol Errors, ,Errors Reading |
18160 | Symbol Files}). | |
104c1213 | 18161 | |
8e04817f | 18162 | @table @code |
104c1213 | 18163 | |
8e04817f AC |
18164 | @kindex set complaints |
18165 | @item set complaints @var{limit} | |
18166 | Permits @value{GDBN} to output @var{limit} complaints about each type of | |
18167 | unusual symbols before becoming silent about the problem. Set | |
18168 | @var{limit} to zero to suppress all complaints; set it to a large number | |
18169 | to prevent complaints from being suppressed. | |
104c1213 | 18170 | |
8e04817f AC |
18171 | @kindex show complaints |
18172 | @item show complaints | |
18173 | Displays how many symbol complaints @value{GDBN} is permitted to produce. | |
104c1213 | 18174 | |
8e04817f | 18175 | @end table |
104c1213 | 18176 | |
d837706a | 18177 | @anchor{confirmation requests} |
8e04817f AC |
18178 | By default, @value{GDBN} is cautious, and asks what sometimes seems to be a |
18179 | lot of stupid questions to confirm certain commands. For example, if | |
18180 | you try to run a program which is already running: | |
104c1213 | 18181 | |
474c8240 | 18182 | @smallexample |
8e04817f AC |
18183 | (@value{GDBP}) run |
18184 | The program being debugged has been started already. | |
18185 | Start it from the beginning? (y or n) | |
474c8240 | 18186 | @end smallexample |
104c1213 | 18187 | |
8e04817f AC |
18188 | If you are willing to unflinchingly face the consequences of your own |
18189 | commands, you can disable this ``feature'': | |
104c1213 | 18190 | |
8e04817f | 18191 | @table @code |
104c1213 | 18192 | |
8e04817f AC |
18193 | @kindex set confirm |
18194 | @cindex flinching | |
18195 | @cindex confirmation | |
18196 | @cindex stupid questions | |
18197 | @item set confirm off | |
18198 | Disables confirmation requests. | |
104c1213 | 18199 | |
8e04817f AC |
18200 | @item set confirm on |
18201 | Enables confirmation requests (the default). | |
104c1213 | 18202 | |
8e04817f AC |
18203 | @kindex show confirm |
18204 | @item show confirm | |
18205 | Displays state of confirmation requests. | |
18206 | ||
18207 | @end table | |
104c1213 | 18208 | |
16026cd7 AS |
18209 | @cindex command tracing |
18210 | If you need to debug user-defined commands or sourced files you may find it | |
18211 | useful to enable @dfn{command tracing}. In this mode each command will be | |
18212 | printed as it is executed, prefixed with one or more @samp{+} symbols, the | |
18213 | quantity denoting the call depth of each command. | |
18214 | ||
18215 | @table @code | |
18216 | @kindex set trace-commands | |
18217 | @cindex command scripts, debugging | |
18218 | @item set trace-commands on | |
18219 | Enable command tracing. | |
18220 | @item set trace-commands off | |
18221 | Disable command tracing. | |
18222 | @item show trace-commands | |
18223 | Display the current state of command tracing. | |
18224 | @end table | |
18225 | ||
8e04817f | 18226 | @node Debugging Output |
79a6e687 | 18227 | @section Optional Messages about Internal Happenings |
4644b6e3 EZ |
18228 | @cindex optional debugging messages |
18229 | ||
da316a69 EZ |
18230 | @value{GDBN} has commands that enable optional debugging messages from |
18231 | various @value{GDBN} subsystems; normally these commands are of | |
18232 | interest to @value{GDBN} maintainers, or when reporting a bug. This | |
18233 | section documents those commands. | |
18234 | ||
104c1213 | 18235 | @table @code |
a8f24a35 EZ |
18236 | @kindex set exec-done-display |
18237 | @item set exec-done-display | |
18238 | Turns on or off the notification of asynchronous commands' | |
18239 | completion. When on, @value{GDBN} will print a message when an | |
18240 | asynchronous command finishes its execution. The default is off. | |
18241 | @kindex show exec-done-display | |
18242 | @item show exec-done-display | |
18243 | Displays the current setting of asynchronous command completion | |
18244 | notification. | |
4644b6e3 EZ |
18245 | @kindex set debug |
18246 | @cindex gdbarch debugging info | |
a8f24a35 | 18247 | @cindex architecture debugging info |
8e04817f | 18248 | @item set debug arch |
a8f24a35 | 18249 | Turns on or off display of gdbarch debugging info. The default is off |
4644b6e3 | 18250 | @kindex show debug |
8e04817f AC |
18251 | @item show debug arch |
18252 | Displays the current state of displaying gdbarch debugging info. | |
721c2651 EZ |
18253 | @item set debug aix-thread |
18254 | @cindex AIX threads | |
18255 | Display debugging messages about inner workings of the AIX thread | |
18256 | module. | |
18257 | @item show debug aix-thread | |
18258 | Show the current state of AIX thread debugging info display. | |
d97bc12b DE |
18259 | @item set debug dwarf2-die |
18260 | @cindex DWARF2 DIEs | |
18261 | Dump DWARF2 DIEs after they are read in. | |
18262 | The value is the number of nesting levels to print. | |
18263 | A value of zero turns off the display. | |
18264 | @item show debug dwarf2-die | |
18265 | Show the current state of DWARF2 DIE debugging. | |
237fc4c9 PA |
18266 | @item set debug displaced |
18267 | @cindex displaced stepping debugging info | |
18268 | Turns on or off display of @value{GDBN} debugging info for the | |
18269 | displaced stepping support. The default is off. | |
18270 | @item show debug displaced | |
18271 | Displays the current state of displaying @value{GDBN} debugging info | |
18272 | related to displaced stepping. | |
8e04817f | 18273 | @item set debug event |
4644b6e3 | 18274 | @cindex event debugging info |
a8f24a35 | 18275 | Turns on or off display of @value{GDBN} event debugging info. The |
8e04817f | 18276 | default is off. |
8e04817f AC |
18277 | @item show debug event |
18278 | Displays the current state of displaying @value{GDBN} event debugging | |
18279 | info. | |
8e04817f | 18280 | @item set debug expression |
4644b6e3 | 18281 | @cindex expression debugging info |
721c2651 EZ |
18282 | Turns on or off display of debugging info about @value{GDBN} |
18283 | expression parsing. The default is off. | |
8e04817f | 18284 | @item show debug expression |
721c2651 EZ |
18285 | Displays the current state of displaying debugging info about |
18286 | @value{GDBN} expression parsing. | |
7453dc06 | 18287 | @item set debug frame |
4644b6e3 | 18288 | @cindex frame debugging info |
7453dc06 AC |
18289 | Turns on or off display of @value{GDBN} frame debugging info. The |
18290 | default is off. | |
7453dc06 AC |
18291 | @item show debug frame |
18292 | Displays the current state of displaying @value{GDBN} frame debugging | |
18293 | info. | |
cbe54154 PA |
18294 | @item set debug gnu-nat |
18295 | @cindex @sc{gnu}/Hurd debug messages | |
18296 | Turns on or off debugging messages from the @sc{gnu}/Hurd debug support. | |
18297 | @item show debug gnu-nat | |
18298 | Show the current state of @sc{gnu}/Hurd debugging messages. | |
30e91e0b RC |
18299 | @item set debug infrun |
18300 | @cindex inferior debugging info | |
18301 | Turns on or off display of @value{GDBN} debugging info for running the inferior. | |
18302 | The default is off. @file{infrun.c} contains GDB's runtime state machine used | |
18303 | for implementing operations such as single-stepping the inferior. | |
18304 | @item show debug infrun | |
18305 | Displays the current state of @value{GDBN} inferior debugging. | |
da316a69 EZ |
18306 | @item set debug lin-lwp |
18307 | @cindex @sc{gnu}/Linux LWP debug messages | |
18308 | @cindex Linux lightweight processes | |
721c2651 | 18309 | Turns on or off debugging messages from the Linux LWP debug support. |
da316a69 EZ |
18310 | @item show debug lin-lwp |
18311 | Show the current state of Linux LWP debugging messages. | |
b84876c2 PA |
18312 | @item set debug lin-lwp-async |
18313 | @cindex @sc{gnu}/Linux LWP async debug messages | |
18314 | @cindex Linux lightweight processes | |
18315 | Turns on or off debugging messages from the Linux LWP async debug support. | |
18316 | @item show debug lin-lwp-async | |
18317 | Show the current state of Linux LWP async debugging messages. | |
2b4855ab | 18318 | @item set debug observer |
4644b6e3 | 18319 | @cindex observer debugging info |
2b4855ab AC |
18320 | Turns on or off display of @value{GDBN} observer debugging. This |
18321 | includes info such as the notification of observable events. | |
2b4855ab AC |
18322 | @item show debug observer |
18323 | Displays the current state of observer debugging. | |
8e04817f | 18324 | @item set debug overload |
4644b6e3 | 18325 | @cindex C@t{++} overload debugging info |
8e04817f | 18326 | Turns on or off display of @value{GDBN} C@t{++} overload debugging |
359df76b | 18327 | info. This includes info such as ranking of functions, etc. The default |
8e04817f | 18328 | is off. |
8e04817f AC |
18329 | @item show debug overload |
18330 | Displays the current state of displaying @value{GDBN} C@t{++} overload | |
18331 | debugging info. | |
8e04817f AC |
18332 | @cindex packets, reporting on stdout |
18333 | @cindex serial connections, debugging | |
605a56cb DJ |
18334 | @cindex debug remote protocol |
18335 | @cindex remote protocol debugging | |
18336 | @cindex display remote packets | |
8e04817f AC |
18337 | @item set debug remote |
18338 | Turns on or off display of reports on all packets sent back and forth across | |
18339 | the serial line to the remote machine. The info is printed on the | |
18340 | @value{GDBN} standard output stream. The default is off. | |
8e04817f AC |
18341 | @item show debug remote |
18342 | Displays the state of display of remote packets. | |
8e04817f AC |
18343 | @item set debug serial |
18344 | Turns on or off display of @value{GDBN} serial debugging info. The | |
18345 | default is off. | |
8e04817f AC |
18346 | @item show debug serial |
18347 | Displays the current state of displaying @value{GDBN} serial debugging | |
18348 | info. | |
c45da7e6 EZ |
18349 | @item set debug solib-frv |
18350 | @cindex FR-V shared-library debugging | |
18351 | Turns on or off debugging messages for FR-V shared-library code. | |
18352 | @item show debug solib-frv | |
18353 | Display the current state of FR-V shared-library code debugging | |
18354 | messages. | |
8e04817f | 18355 | @item set debug target |
4644b6e3 | 18356 | @cindex target debugging info |
8e04817f AC |
18357 | Turns on or off display of @value{GDBN} target debugging info. This info |
18358 | includes what is going on at the target level of GDB, as it happens. The | |
701b08bb DJ |
18359 | default is 0. Set it to 1 to track events, and to 2 to also track the |
18360 | value of large memory transfers. Changes to this flag do not take effect | |
18361 | until the next time you connect to a target or use the @code{run} command. | |
8e04817f AC |
18362 | @item show debug target |
18363 | Displays the current state of displaying @value{GDBN} target debugging | |
18364 | info. | |
75feb17d DJ |
18365 | @item set debug timestamp |
18366 | @cindex timestampping debugging info | |
18367 | Turns on or off display of timestamps with @value{GDBN} debugging info. | |
18368 | When enabled, seconds and microseconds are displayed before each debugging | |
18369 | message. | |
18370 | @item show debug timestamp | |
18371 | Displays the current state of displaying timestamps with @value{GDBN} | |
18372 | debugging info. | |
c45da7e6 | 18373 | @item set debugvarobj |
4644b6e3 | 18374 | @cindex variable object debugging info |
8e04817f AC |
18375 | Turns on or off display of @value{GDBN} variable object debugging |
18376 | info. The default is off. | |
c45da7e6 | 18377 | @item show debugvarobj |
8e04817f AC |
18378 | Displays the current state of displaying @value{GDBN} variable object |
18379 | debugging info. | |
e776119f DJ |
18380 | @item set debug xml |
18381 | @cindex XML parser debugging | |
18382 | Turns on or off debugging messages for built-in XML parsers. | |
18383 | @item show debug xml | |
18384 | Displays the current state of XML debugging messages. | |
8e04817f | 18385 | @end table |
104c1213 | 18386 | |
14fb1bac JB |
18387 | @node Other Misc Settings |
18388 | @section Other Miscellaneous Settings | |
18389 | @cindex miscellaneous settings | |
18390 | ||
18391 | @table @code | |
18392 | @kindex set interactive-mode | |
18393 | @item set interactive-mode | |
18394 | If @code{on}, forces @value{GDBN} to operate interactively. | |
18395 | If @code{off}, forces @value{GDBN} to operate non-interactively, | |
18396 | If @code{auto} (the default), @value{GDBN} guesses which mode to use, | |
18397 | based on whether the debugger was started in a terminal or not. | |
18398 | ||
18399 | In the vast majority of cases, the debugger should be able to guess | |
18400 | correctly which mode should be used. But this setting can be useful | |
18401 | in certain specific cases, such as running a MinGW @value{GDBN} | |
18402 | inside a cygwin window. | |
18403 | ||
18404 | @kindex show interactive-mode | |
18405 | @item show interactive-mode | |
18406 | Displays whether the debugger is operating in interactive mode or not. | |
18407 | @end table | |
18408 | ||
d57a3c85 TJB |
18409 | @node Extending GDB |
18410 | @chapter Extending @value{GDBN} | |
18411 | @cindex extending GDB | |
18412 | ||
18413 | @value{GDBN} provides two mechanisms for extension. The first is based | |
18414 | on composition of @value{GDBN} commands, and the second is based on the | |
18415 | Python scripting language. | |
18416 | ||
18417 | @menu | |
18418 | * Sequences:: Canned Sequences of Commands | |
18419 | * Python:: Scripting @value{GDBN} using Python | |
18420 | @end menu | |
18421 | ||
8e04817f | 18422 | @node Sequences |
d57a3c85 | 18423 | @section Canned Sequences of Commands |
104c1213 | 18424 | |
8e04817f | 18425 | Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint |
79a6e687 | 18426 | Command Lists}), @value{GDBN} provides two ways to store sequences of |
8e04817f AC |
18427 | commands for execution as a unit: user-defined commands and command |
18428 | files. | |
104c1213 | 18429 | |
8e04817f | 18430 | @menu |
fcc73fe3 EZ |
18431 | * Define:: How to define your own commands |
18432 | * Hooks:: Hooks for user-defined commands | |
18433 | * Command Files:: How to write scripts of commands to be stored in a file | |
18434 | * Output:: Commands for controlled output | |
8e04817f | 18435 | @end menu |
104c1213 | 18436 | |
8e04817f | 18437 | @node Define |
d57a3c85 | 18438 | @subsection User-defined Commands |
104c1213 | 18439 | |
8e04817f | 18440 | @cindex user-defined command |
fcc73fe3 | 18441 | @cindex arguments, to user-defined commands |
8e04817f AC |
18442 | A @dfn{user-defined command} is a sequence of @value{GDBN} commands to |
18443 | which you assign a new name as a command. This is done with the | |
18444 | @code{define} command. User commands may accept up to 10 arguments | |
18445 | separated by whitespace. Arguments are accessed within the user command | |
c03c782f | 18446 | via @code{$arg0@dots{}$arg9}. A trivial example: |
104c1213 | 18447 | |
8e04817f AC |
18448 | @smallexample |
18449 | define adder | |
18450 | print $arg0 + $arg1 + $arg2 | |
c03c782f | 18451 | end |
8e04817f | 18452 | @end smallexample |
104c1213 JM |
18453 | |
18454 | @noindent | |
8e04817f | 18455 | To execute the command use: |
104c1213 | 18456 | |
8e04817f AC |
18457 | @smallexample |
18458 | adder 1 2 3 | |
18459 | @end smallexample | |
104c1213 | 18460 | |
8e04817f AC |
18461 | @noindent |
18462 | This defines the command @code{adder}, which prints the sum of | |
18463 | its three arguments. Note the arguments are text substitutions, so they may | |
18464 | reference variables, use complex expressions, or even perform inferior | |
18465 | functions calls. | |
104c1213 | 18466 | |
fcc73fe3 EZ |
18467 | @cindex argument count in user-defined commands |
18468 | @cindex how many arguments (user-defined commands) | |
c03c782f AS |
18469 | In addition, @code{$argc} may be used to find out how many arguments have |
18470 | been passed. This expands to a number in the range 0@dots{}10. | |
18471 | ||
18472 | @smallexample | |
18473 | define adder | |
18474 | if $argc == 2 | |
18475 | print $arg0 + $arg1 | |
18476 | end | |
18477 | if $argc == 3 | |
18478 | print $arg0 + $arg1 + $arg2 | |
18479 | end | |
18480 | end | |
18481 | @end smallexample | |
18482 | ||
104c1213 | 18483 | @table @code |
104c1213 | 18484 | |
8e04817f AC |
18485 | @kindex define |
18486 | @item define @var{commandname} | |
18487 | Define a command named @var{commandname}. If there is already a command | |
18488 | by that name, you are asked to confirm that you want to redefine it. | |
adb483fe DJ |
18489 | @var{commandname} may be a bare command name consisting of letters, |
18490 | numbers, dashes, and underscores. It may also start with any predefined | |
18491 | prefix command. For example, @samp{define target my-target} creates | |
18492 | a user-defined @samp{target my-target} command. | |
104c1213 | 18493 | |
8e04817f AC |
18494 | The definition of the command is made up of other @value{GDBN} command lines, |
18495 | which are given following the @code{define} command. The end of these | |
18496 | commands is marked by a line containing @code{end}. | |
104c1213 | 18497 | |
8e04817f | 18498 | @kindex document |
ca91424e | 18499 | @kindex end@r{ (user-defined commands)} |
8e04817f AC |
18500 | @item document @var{commandname} |
18501 | Document the user-defined command @var{commandname}, so that it can be | |
18502 | accessed by @code{help}. The command @var{commandname} must already be | |
18503 | defined. This command reads lines of documentation just as @code{define} | |
18504 | reads the lines of the command definition, ending with @code{end}. | |
18505 | After the @code{document} command is finished, @code{help} on command | |
18506 | @var{commandname} displays the documentation you have written. | |
104c1213 | 18507 | |
8e04817f AC |
18508 | You may use the @code{document} command again to change the |
18509 | documentation of a command. Redefining the command with @code{define} | |
18510 | does not change the documentation. | |
104c1213 | 18511 | |
c45da7e6 EZ |
18512 | @kindex dont-repeat |
18513 | @cindex don't repeat command | |
18514 | @item dont-repeat | |
18515 | Used inside a user-defined command, this tells @value{GDBN} that this | |
18516 | command should not be repeated when the user hits @key{RET} | |
18517 | (@pxref{Command Syntax, repeat last command}). | |
18518 | ||
8e04817f AC |
18519 | @kindex help user-defined |
18520 | @item help user-defined | |
18521 | List all user-defined commands, with the first line of the documentation | |
18522 | (if any) for each. | |
104c1213 | 18523 | |
8e04817f AC |
18524 | @kindex show user |
18525 | @item show user | |
18526 | @itemx show user @var{commandname} | |
18527 | Display the @value{GDBN} commands used to define @var{commandname} (but | |
18528 | not its documentation). If no @var{commandname} is given, display the | |
18529 | definitions for all user-defined commands. | |
104c1213 | 18530 | |
fcc73fe3 | 18531 | @cindex infinite recursion in user-defined commands |
20f01a46 DH |
18532 | @kindex show max-user-call-depth |
18533 | @kindex set max-user-call-depth | |
18534 | @item show max-user-call-depth | |
5ca0cb28 DH |
18535 | @itemx set max-user-call-depth |
18536 | The value of @code{max-user-call-depth} controls how many recursion | |
3f94c067 | 18537 | levels are allowed in user-defined commands before @value{GDBN} suspects an |
5ca0cb28 | 18538 | infinite recursion and aborts the command. |
104c1213 JM |
18539 | @end table |
18540 | ||
fcc73fe3 EZ |
18541 | In addition to the above commands, user-defined commands frequently |
18542 | use control flow commands, described in @ref{Command Files}. | |
18543 | ||
8e04817f AC |
18544 | When user-defined commands are executed, the |
18545 | commands of the definition are not printed. An error in any command | |
18546 | stops execution of the user-defined command. | |
104c1213 | 18547 | |
8e04817f AC |
18548 | If used interactively, commands that would ask for confirmation proceed |
18549 | without asking when used inside a user-defined command. Many @value{GDBN} | |
18550 | commands that normally print messages to say what they are doing omit the | |
18551 | messages when used in a user-defined command. | |
104c1213 | 18552 | |
8e04817f | 18553 | @node Hooks |
d57a3c85 | 18554 | @subsection User-defined Command Hooks |
8e04817f AC |
18555 | @cindex command hooks |
18556 | @cindex hooks, for commands | |
18557 | @cindex hooks, pre-command | |
104c1213 | 18558 | |
8e04817f | 18559 | @kindex hook |
8e04817f AC |
18560 | You may define @dfn{hooks}, which are a special kind of user-defined |
18561 | command. Whenever you run the command @samp{foo}, if the user-defined | |
18562 | command @samp{hook-foo} exists, it is executed (with no arguments) | |
18563 | before that command. | |
104c1213 | 18564 | |
8e04817f AC |
18565 | @cindex hooks, post-command |
18566 | @kindex hookpost | |
8e04817f AC |
18567 | A hook may also be defined which is run after the command you executed. |
18568 | Whenever you run the command @samp{foo}, if the user-defined command | |
18569 | @samp{hookpost-foo} exists, it is executed (with no arguments) after | |
18570 | that command. Post-execution hooks may exist simultaneously with | |
18571 | pre-execution hooks, for the same command. | |
104c1213 | 18572 | |
8e04817f | 18573 | It is valid for a hook to call the command which it hooks. If this |
9f1c6395 | 18574 | occurs, the hook is not re-executed, thereby avoiding infinite recursion. |
104c1213 | 18575 | |
8e04817f AC |
18576 | @c It would be nice if hookpost could be passed a parameter indicating |
18577 | @c if the command it hooks executed properly or not. FIXME! | |
104c1213 | 18578 | |
8e04817f AC |
18579 | @kindex stop@r{, a pseudo-command} |
18580 | In addition, a pseudo-command, @samp{stop} exists. Defining | |
18581 | (@samp{hook-stop}) makes the associated commands execute every time | |
18582 | execution stops in your program: before breakpoint commands are run, | |
18583 | displays are printed, or the stack frame is printed. | |
104c1213 | 18584 | |
8e04817f AC |
18585 | For example, to ignore @code{SIGALRM} signals while |
18586 | single-stepping, but treat them normally during normal execution, | |
18587 | you could define: | |
104c1213 | 18588 | |
474c8240 | 18589 | @smallexample |
8e04817f AC |
18590 | define hook-stop |
18591 | handle SIGALRM nopass | |
18592 | end | |
104c1213 | 18593 | |
8e04817f AC |
18594 | define hook-run |
18595 | handle SIGALRM pass | |
18596 | end | |
104c1213 | 18597 | |
8e04817f | 18598 | define hook-continue |
d3e8051b | 18599 | handle SIGALRM pass |
8e04817f | 18600 | end |
474c8240 | 18601 | @end smallexample |
104c1213 | 18602 | |
d3e8051b | 18603 | As a further example, to hook at the beginning and end of the @code{echo} |
b383017d | 18604 | command, and to add extra text to the beginning and end of the message, |
8e04817f | 18605 | you could define: |
104c1213 | 18606 | |
474c8240 | 18607 | @smallexample |
8e04817f AC |
18608 | define hook-echo |
18609 | echo <<<--- | |
18610 | end | |
104c1213 | 18611 | |
8e04817f AC |
18612 | define hookpost-echo |
18613 | echo --->>>\n | |
18614 | end | |
104c1213 | 18615 | |
8e04817f AC |
18616 | (@value{GDBP}) echo Hello World |
18617 | <<<---Hello World--->>> | |
18618 | (@value{GDBP}) | |
104c1213 | 18619 | |
474c8240 | 18620 | @end smallexample |
104c1213 | 18621 | |
8e04817f AC |
18622 | You can define a hook for any single-word command in @value{GDBN}, but |
18623 | not for command aliases; you should define a hook for the basic command | |
c1468174 | 18624 | name, e.g.@: @code{backtrace} rather than @code{bt}. |
8e04817f AC |
18625 | @c FIXME! So how does Joe User discover whether a command is an alias |
18626 | @c or not? | |
adb483fe DJ |
18627 | You can hook a multi-word command by adding @code{hook-} or |
18628 | @code{hookpost-} to the last word of the command, e.g.@: | |
18629 | @samp{define target hook-remote} to add a hook to @samp{target remote}. | |
18630 | ||
8e04817f AC |
18631 | If an error occurs during the execution of your hook, execution of |
18632 | @value{GDBN} commands stops and @value{GDBN} issues a prompt | |
18633 | (before the command that you actually typed had a chance to run). | |
104c1213 | 18634 | |
8e04817f AC |
18635 | If you try to define a hook which does not match any known command, you |
18636 | get a warning from the @code{define} command. | |
c906108c | 18637 | |
8e04817f | 18638 | @node Command Files |
d57a3c85 | 18639 | @subsection Command Files |
c906108c | 18640 | |
8e04817f | 18641 | @cindex command files |
fcc73fe3 | 18642 | @cindex scripting commands |
6fc08d32 EZ |
18643 | A command file for @value{GDBN} is a text file made of lines that are |
18644 | @value{GDBN} commands. Comments (lines starting with @kbd{#}) may | |
18645 | also be included. An empty line in a command file does nothing; it | |
18646 | does not mean to repeat the last command, as it would from the | |
18647 | terminal. | |
c906108c | 18648 | |
6fc08d32 EZ |
18649 | You can request the execution of a command file with the @code{source} |
18650 | command: | |
c906108c | 18651 | |
8e04817f AC |
18652 | @table @code |
18653 | @kindex source | |
ca91424e | 18654 | @cindex execute commands from a file |
16026cd7 | 18655 | @item source [@code{-v}] @var{filename} |
8e04817f | 18656 | Execute the command file @var{filename}. |
c906108c SS |
18657 | @end table |
18658 | ||
fcc73fe3 EZ |
18659 | The lines in a command file are generally executed sequentially, |
18660 | unless the order of execution is changed by one of the | |
18661 | @emph{flow-control commands} described below. The commands are not | |
a71ec265 DH |
18662 | printed as they are executed. An error in any command terminates |
18663 | execution of the command file and control is returned to the console. | |
c906108c | 18664 | |
4b505b12 AS |
18665 | @value{GDBN} searches for @var{filename} in the current directory and then |
18666 | on the search path (specified with the @samp{directory} command). | |
18667 | ||
16026cd7 AS |
18668 | If @code{-v}, for verbose mode, is given then @value{GDBN} displays |
18669 | each command as it is executed. The option must be given before | |
18670 | @var{filename}, and is interpreted as part of the filename anywhere else. | |
18671 | ||
8e04817f AC |
18672 | Commands that would ask for confirmation if used interactively proceed |
18673 | without asking when used in a command file. Many @value{GDBN} commands that | |
18674 | normally print messages to say what they are doing omit the messages | |
18675 | when called from command files. | |
c906108c | 18676 | |
8e04817f AC |
18677 | @value{GDBN} also accepts command input from standard input. In this |
18678 | mode, normal output goes to standard output and error output goes to | |
18679 | standard error. Errors in a command file supplied on standard input do | |
6fc08d32 | 18680 | not terminate execution of the command file---execution continues with |
8e04817f | 18681 | the next command. |
c906108c | 18682 | |
474c8240 | 18683 | @smallexample |
8e04817f | 18684 | gdb < cmds > log 2>&1 |
474c8240 | 18685 | @end smallexample |
c906108c | 18686 | |
8e04817f AC |
18687 | (The syntax above will vary depending on the shell used.) This example |
18688 | will execute commands from the file @file{cmds}. All output and errors | |
18689 | would be directed to @file{log}. | |
c906108c | 18690 | |
fcc73fe3 EZ |
18691 | Since commands stored on command files tend to be more general than |
18692 | commands typed interactively, they frequently need to deal with | |
18693 | complicated situations, such as different or unexpected values of | |
18694 | variables and symbols, changes in how the program being debugged is | |
18695 | built, etc. @value{GDBN} provides a set of flow-control commands to | |
18696 | deal with these complexities. Using these commands, you can write | |
18697 | complex scripts that loop over data structures, execute commands | |
18698 | conditionally, etc. | |
18699 | ||
18700 | @table @code | |
18701 | @kindex if | |
18702 | @kindex else | |
18703 | @item if | |
18704 | @itemx else | |
18705 | This command allows to include in your script conditionally executed | |
18706 | commands. The @code{if} command takes a single argument, which is an | |
18707 | expression to evaluate. It is followed by a series of commands that | |
18708 | are executed only if the expression is true (its value is nonzero). | |
18709 | There can then optionally be an @code{else} line, followed by a series | |
18710 | of commands that are only executed if the expression was false. The | |
18711 | end of the list is marked by a line containing @code{end}. | |
18712 | ||
18713 | @kindex while | |
18714 | @item while | |
18715 | This command allows to write loops. Its syntax is similar to | |
18716 | @code{if}: the command takes a single argument, which is an expression | |
18717 | to evaluate, and must be followed by the commands to execute, one per | |
18718 | line, terminated by an @code{end}. These commands are called the | |
18719 | @dfn{body} of the loop. The commands in the body of @code{while} are | |
18720 | executed repeatedly as long as the expression evaluates to true. | |
18721 | ||
18722 | @kindex loop_break | |
18723 | @item loop_break | |
18724 | This command exits the @code{while} loop in whose body it is included. | |
18725 | Execution of the script continues after that @code{while}s @code{end} | |
18726 | line. | |
18727 | ||
18728 | @kindex loop_continue | |
18729 | @item loop_continue | |
18730 | This command skips the execution of the rest of the body of commands | |
18731 | in the @code{while} loop in whose body it is included. Execution | |
18732 | branches to the beginning of the @code{while} loop, where it evaluates | |
18733 | the controlling expression. | |
ca91424e EZ |
18734 | |
18735 | @kindex end@r{ (if/else/while commands)} | |
18736 | @item end | |
18737 | Terminate the block of commands that are the body of @code{if}, | |
18738 | @code{else}, or @code{while} flow-control commands. | |
fcc73fe3 EZ |
18739 | @end table |
18740 | ||
18741 | ||
8e04817f | 18742 | @node Output |
d57a3c85 | 18743 | @subsection Commands for Controlled Output |
c906108c | 18744 | |
8e04817f AC |
18745 | During the execution of a command file or a user-defined command, normal |
18746 | @value{GDBN} output is suppressed; the only output that appears is what is | |
18747 | explicitly printed by the commands in the definition. This section | |
18748 | describes three commands useful for generating exactly the output you | |
18749 | want. | |
c906108c SS |
18750 | |
18751 | @table @code | |
8e04817f AC |
18752 | @kindex echo |
18753 | @item echo @var{text} | |
18754 | @c I do not consider backslash-space a standard C escape sequence | |
18755 | @c because it is not in ANSI. | |
18756 | Print @var{text}. Nonprinting characters can be included in | |
18757 | @var{text} using C escape sequences, such as @samp{\n} to print a | |
18758 | newline. @strong{No newline is printed unless you specify one.} | |
18759 | In addition to the standard C escape sequences, a backslash followed | |
18760 | by a space stands for a space. This is useful for displaying a | |
18761 | string with spaces at the beginning or the end, since leading and | |
18762 | trailing spaces are otherwise trimmed from all arguments. | |
18763 | To print @samp{@w{ }and foo =@w{ }}, use the command | |
18764 | @samp{echo \@w{ }and foo = \@w{ }}. | |
c906108c | 18765 | |
8e04817f AC |
18766 | A backslash at the end of @var{text} can be used, as in C, to continue |
18767 | the command onto subsequent lines. For example, | |
c906108c | 18768 | |
474c8240 | 18769 | @smallexample |
8e04817f AC |
18770 | echo This is some text\n\ |
18771 | which is continued\n\ | |
18772 | onto several lines.\n | |
474c8240 | 18773 | @end smallexample |
c906108c | 18774 | |
8e04817f | 18775 | produces the same output as |
c906108c | 18776 | |
474c8240 | 18777 | @smallexample |
8e04817f AC |
18778 | echo This is some text\n |
18779 | echo which is continued\n | |
18780 | echo onto several lines.\n | |
474c8240 | 18781 | @end smallexample |
c906108c | 18782 | |
8e04817f AC |
18783 | @kindex output |
18784 | @item output @var{expression} | |
18785 | Print the value of @var{expression} and nothing but that value: no | |
18786 | newlines, no @samp{$@var{nn} = }. The value is not entered in the | |
18787 | value history either. @xref{Expressions, ,Expressions}, for more information | |
18788 | on expressions. | |
c906108c | 18789 | |
8e04817f AC |
18790 | @item output/@var{fmt} @var{expression} |
18791 | Print the value of @var{expression} in format @var{fmt}. You can use | |
18792 | the same formats as for @code{print}. @xref{Output Formats,,Output | |
79a6e687 | 18793 | Formats}, for more information. |
c906108c | 18794 | |
8e04817f | 18795 | @kindex printf |
82160952 EZ |
18796 | @item printf @var{template}, @var{expressions}@dots{} |
18797 | Print the values of one or more @var{expressions} under the control of | |
18798 | the string @var{template}. To print several values, make | |
18799 | @var{expressions} be a comma-separated list of individual expressions, | |
18800 | which may be either numbers or pointers. Their values are printed as | |
18801 | specified by @var{template}, exactly as a C program would do by | |
18802 | executing the code below: | |
c906108c | 18803 | |
474c8240 | 18804 | @smallexample |
82160952 | 18805 | printf (@var{template}, @var{expressions}@dots{}); |
474c8240 | 18806 | @end smallexample |
c906108c | 18807 | |
82160952 EZ |
18808 | As in @code{C} @code{printf}, ordinary characters in @var{template} |
18809 | are printed verbatim, while @dfn{conversion specification} introduced | |
18810 | by the @samp{%} character cause subsequent @var{expressions} to be | |
18811 | evaluated, their values converted and formatted according to type and | |
18812 | style information encoded in the conversion specifications, and then | |
18813 | printed. | |
18814 | ||
8e04817f | 18815 | For example, you can print two values in hex like this: |
c906108c | 18816 | |
8e04817f AC |
18817 | @smallexample |
18818 | printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo | |
18819 | @end smallexample | |
c906108c | 18820 | |
82160952 EZ |
18821 | @code{printf} supports all the standard @code{C} conversion |
18822 | specifications, including the flags and modifiers between the @samp{%} | |
18823 | character and the conversion letter, with the following exceptions: | |
18824 | ||
18825 | @itemize @bullet | |
18826 | @item | |
18827 | The argument-ordering modifiers, such as @samp{2$}, are not supported. | |
18828 | ||
18829 | @item | |
18830 | The modifier @samp{*} is not supported for specifying precision or | |
18831 | width. | |
18832 | ||
18833 | @item | |
18834 | The @samp{'} flag (for separation of digits into groups according to | |
18835 | @code{LC_NUMERIC'}) is not supported. | |
18836 | ||
18837 | @item | |
18838 | The type modifiers @samp{hh}, @samp{j}, @samp{t}, and @samp{z} are not | |
18839 | supported. | |
18840 | ||
18841 | @item | |
18842 | The conversion letter @samp{n} (as in @samp{%n}) is not supported. | |
18843 | ||
18844 | @item | |
18845 | The conversion letters @samp{a} and @samp{A} are not supported. | |
18846 | @end itemize | |
18847 | ||
18848 | @noindent | |
18849 | Note that the @samp{ll} type modifier is supported only if the | |
18850 | underlying @code{C} implementation used to build @value{GDBN} supports | |
18851 | the @code{long long int} type, and the @samp{L} type modifier is | |
18852 | supported only if @code{long double} type is available. | |
18853 | ||
18854 | As in @code{C}, @code{printf} supports simple backslash-escape | |
18855 | sequences, such as @code{\n}, @samp{\t}, @samp{\\}, @samp{\"}, | |
18856 | @samp{\a}, and @samp{\f}, that consist of backslash followed by a | |
18857 | single character. Octal and hexadecimal escape sequences are not | |
18858 | supported. | |
1a619819 LM |
18859 | |
18860 | Additionally, @code{printf} supports conversion specifications for DFP | |
0aea4bf3 LM |
18861 | (@dfn{Decimal Floating Point}) types using the following length modifiers |
18862 | together with a floating point specifier. | |
1a619819 LM |
18863 | letters: |
18864 | ||
18865 | @itemize @bullet | |
18866 | @item | |
18867 | @samp{H} for printing @code{Decimal32} types. | |
18868 | ||
18869 | @item | |
18870 | @samp{D} for printing @code{Decimal64} types. | |
18871 | ||
18872 | @item | |
18873 | @samp{DD} for printing @code{Decimal128} types. | |
18874 | @end itemize | |
18875 | ||
18876 | If the underlying @code{C} implementation used to build @value{GDBN} has | |
0aea4bf3 | 18877 | support for the three length modifiers for DFP types, other modifiers |
3b784c4f | 18878 | such as width and precision will also be available for @value{GDBN} to use. |
1a619819 LM |
18879 | |
18880 | In case there is no such @code{C} support, no additional modifiers will be | |
18881 | available and the value will be printed in the standard way. | |
18882 | ||
18883 | Here's an example of printing DFP types using the above conversion letters: | |
18884 | @smallexample | |
0aea4bf3 | 18885 | printf "D32: %Hf - D64: %Df - D128: %DDf\n",1.2345df,1.2E10dd,1.2E1dl |
1a619819 LM |
18886 | @end smallexample |
18887 | ||
c906108c SS |
18888 | @end table |
18889 | ||
d57a3c85 TJB |
18890 | @node Python |
18891 | @section Scripting @value{GDBN} using Python | |
18892 | @cindex python scripting | |
18893 | @cindex scripting with python | |
18894 | ||
18895 | You can script @value{GDBN} using the @uref{http://www.python.org/, | |
18896 | Python programming language}. This feature is available only if | |
18897 | @value{GDBN} was configured using @option{--with-python}. | |
18898 | ||
18899 | @menu | |
18900 | * Python Commands:: Accessing Python from @value{GDBN}. | |
18901 | * Python API:: Accessing @value{GDBN} from Python. | |
18902 | @end menu | |
18903 | ||
18904 | @node Python Commands | |
18905 | @subsection Python Commands | |
18906 | @cindex python commands | |
18907 | @cindex commands to access python | |
18908 | ||
18909 | @value{GDBN} provides one command for accessing the Python interpreter, | |
18910 | and one related setting: | |
18911 | ||
18912 | @table @code | |
18913 | @kindex python | |
18914 | @item python @r{[}@var{code}@r{]} | |
18915 | The @code{python} command can be used to evaluate Python code. | |
18916 | ||
18917 | If given an argument, the @code{python} command will evaluate the | |
18918 | argument as a Python command. For example: | |
18919 | ||
18920 | @smallexample | |
18921 | (@value{GDBP}) python print 23 | |
18922 | 23 | |
18923 | @end smallexample | |
18924 | ||
18925 | If you do not provide an argument to @code{python}, it will act as a | |
18926 | multi-line command, like @code{define}. In this case, the Python | |
18927 | script is made up of subsequent command lines, given after the | |
18928 | @code{python} command. This command list is terminated using a line | |
18929 | containing @code{end}. For example: | |
18930 | ||
18931 | @smallexample | |
18932 | (@value{GDBP}) python | |
18933 | Type python script | |
18934 | End with a line saying just "end". | |
18935 | >print 23 | |
18936 | >end | |
18937 | 23 | |
18938 | @end smallexample | |
18939 | ||
18940 | @kindex maint set python print-stack | |
18941 | @item maint set python print-stack | |
18942 | By default, @value{GDBN} will print a stack trace when an error occurs | |
18943 | in a Python script. This can be controlled using @code{maint set | |
18944 | python print-stack}: if @code{on}, the default, then Python stack | |
18945 | printing is enabled; if @code{off}, then Python stack printing is | |
18946 | disabled. | |
18947 | @end table | |
18948 | ||
18949 | @node Python API | |
18950 | @subsection Python API | |
18951 | @cindex python api | |
18952 | @cindex programming in python | |
18953 | ||
18954 | @cindex python stdout | |
18955 | @cindex python pagination | |
18956 | At startup, @value{GDBN} overrides Python's @code{sys.stdout} and | |
18957 | @code{sys.stderr} to print using @value{GDBN}'s output-paging streams. | |
18958 | A Python program which outputs to one of these streams may have its | |
18959 | output interrupted by the user (@pxref{Screen Size}). In this | |
18960 | situation, a Python @code{KeyboardInterrupt} exception is thrown. | |
18961 | ||
18962 | @menu | |
18963 | * Basic Python:: Basic Python Functions. | |
18964 | * Exception Handling:: | |
89c73ade | 18965 | * Auto-loading:: Automatically loading Python code. |
a08702d6 | 18966 | * Values From Inferior:: |
2c74e833 | 18967 | * Types In Python:: Python representation of types. |
a6bac58e TT |
18968 | * Pretty Printing:: Pretty-printing values. |
18969 | * Selecting Pretty-Printers:: How GDB chooses a pretty-printer. | |
d8906c6f | 18970 | * Commands In Python:: Implementing new commands in Python. |
bc3b79fd | 18971 | * Functions In Python:: Writing new convenience functions. |
89c73ade | 18972 | * Objfiles In Python:: Object files. |
f8f6f20b | 18973 | * Frames In Python:: Acessing inferior stack frames from Python. |
d57a3c85 TJB |
18974 | @end menu |
18975 | ||
18976 | @node Basic Python | |
18977 | @subsubsection Basic Python | |
18978 | ||
18979 | @cindex python functions | |
18980 | @cindex python module | |
18981 | @cindex gdb module | |
18982 | @value{GDBN} introduces a new Python module, named @code{gdb}. All | |
18983 | methods and classes added by @value{GDBN} are placed in this module. | |
18984 | @value{GDBN} automatically @code{import}s the @code{gdb} module for | |
18985 | use in all scripts evaluated by the @code{python} command. | |
18986 | ||
18987 | @findex gdb.execute | |
12453b93 | 18988 | @defun execute command [from_tty] |
d57a3c85 TJB |
18989 | Evaluate @var{command}, a string, as a @value{GDBN} CLI command. |
18990 | If a GDB exception happens while @var{command} runs, it is | |
18991 | translated as described in @ref{Exception Handling,,Exception Handling}. | |
18992 | If no exceptions occur, this function returns @code{None}. | |
12453b93 TJB |
18993 | |
18994 | @var{from_tty} specifies whether @value{GDBN} ought to consider this | |
18995 | command as having originated from the user invoking it interactively. | |
18996 | It must be a boolean value. If omitted, it defaults to @code{False}. | |
d57a3c85 TJB |
18997 | @end defun |
18998 | ||
8f500870 TT |
18999 | @findex gdb.parameter |
19000 | @defun parameter parameter | |
d57a3c85 TJB |
19001 | Return the value of a @value{GDBN} parameter. @var{parameter} is a |
19002 | string naming the parameter to look up; @var{parameter} may contain | |
19003 | spaces if the parameter has a multi-part name. For example, | |
19004 | @samp{print object} is a valid parameter name. | |
19005 | ||
19006 | If the named parameter does not exist, this function throws a | |
19007 | @code{RuntimeError}. Otherwise, the parameter's value is converted to | |
19008 | a Python value of the appropriate type, and returned. | |
19009 | @end defun | |
19010 | ||
08c637de TJB |
19011 | @findex gdb.history |
19012 | @defun history number | |
19013 | Return a value from @value{GDBN}'s value history (@pxref{Value | |
19014 | History}). @var{number} indicates which history element to return. | |
19015 | If @var{number} is negative, then @value{GDBN} will take its absolute value | |
19016 | and count backward from the last element (i.e., the most recent element) to | |
19017 | find the value to return. If @var{number} is zero, then @value{GDBN} will | |
a0c36267 | 19018 | return the most recent element. If the element specified by @var{number} |
08c637de TJB |
19019 | doesn't exist in the value history, a @code{RuntimeError} exception will be |
19020 | raised. | |
19021 | ||
19022 | If no exception is raised, the return value is always an instance of | |
19023 | @code{gdb.Value} (@pxref{Values From Inferior}). | |
19024 | @end defun | |
19025 | ||
d57a3c85 TJB |
19026 | @findex gdb.write |
19027 | @defun write string | |
19028 | Print a string to @value{GDBN}'s paginated standard output stream. | |
19029 | Writing to @code{sys.stdout} or @code{sys.stderr} will automatically | |
19030 | call this function. | |
19031 | @end defun | |
19032 | ||
19033 | @findex gdb.flush | |
19034 | @defun flush | |
19035 | Flush @value{GDBN}'s paginated standard output stream. Flushing | |
19036 | @code{sys.stdout} or @code{sys.stderr} will automatically call this | |
19037 | function. | |
19038 | @end defun | |
19039 | ||
19040 | @node Exception Handling | |
19041 | @subsubsection Exception Handling | |
19042 | @cindex python exceptions | |
19043 | @cindex exceptions, python | |
19044 | ||
19045 | When executing the @code{python} command, Python exceptions | |
19046 | uncaught within the Python code are translated to calls to | |
19047 | @value{GDBN} error-reporting mechanism. If the command that called | |
19048 | @code{python} does not handle the error, @value{GDBN} will | |
19049 | terminate it and print an error message containing the Python | |
19050 | exception name, the associated value, and the Python call stack | |
19051 | backtrace at the point where the exception was raised. Example: | |
19052 | ||
19053 | @smallexample | |
19054 | (@value{GDBP}) python print foo | |
19055 | Traceback (most recent call last): | |
19056 | File "<string>", line 1, in <module> | |
19057 | NameError: name 'foo' is not defined | |
19058 | @end smallexample | |
19059 | ||
19060 | @value{GDBN} errors that happen in @value{GDBN} commands invoked by Python | |
19061 | code are converted to Python @code{RuntimeError} exceptions. User | |
19062 | interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination | |
19063 | prompt) is translated to a Python @code{KeyboardInterrupt} | |
19064 | exception. If you catch these exceptions in your Python code, your | |
19065 | exception handler will see @code{RuntimeError} or | |
19066 | @code{KeyboardInterrupt} as the exception type, the @value{GDBN} error | |
19067 | message as its value, and the Python call stack backtrace at the | |
19068 | Python statement closest to where the @value{GDBN} error occured as the | |
19069 | traceback. | |
19070 | ||
89c73ade TT |
19071 | @node Auto-loading |
19072 | @subsubsection Auto-loading | |
19073 | @cindex auto-loading, Python | |
19074 | ||
19075 | When a new object file is read (for example, due to the @code{file} | |
19076 | command, or because the inferior has loaded a shared library), | |
19077 | @value{GDBN} will look for a file named @file{@var{objfile}-gdb.py}, | |
19078 | where @var{objfile} is the object file's real name, formed by ensuring | |
19079 | that the file name is absolute, following all symlinks, and resolving | |
19080 | @code{.} and @code{..} components. If this file exists and is | |
19081 | readable, @value{GDBN} will evaluate it as a Python script. | |
19082 | ||
19083 | If this file does not exist, and if the parameter | |
19084 | @code{debug-file-directory} is set (@pxref{Separate Debug Files}), | |
19085 | then @value{GDBN} will use the file named | |
19086 | @file{@var{debug-file-directory}/@var{real-name}}, where | |
19087 | @var{real-name} is the object file's real name, as described above. | |
19088 | ||
19089 | Finally, if this file does not exist, then @value{GDBN} will look for | |
19090 | a file named @file{@var{data-directory}/python/auto-load/@var{real-name}}, where | |
19091 | @var{data-directory} is @value{GDBN}'s data directory (available via | |
19092 | @code{show data-directory}, @pxref{Data Files}), and @var{real-name} | |
19093 | is the object file's real name, as described above. | |
19094 | ||
19095 | When reading an auto-loaded file, @value{GDBN} sets the ``current | |
19096 | objfile''. This is available via the @code{gdb.current_objfile} | |
19097 | function (@pxref{Objfiles In Python}). This can be useful for | |
19098 | registering objfile-specific pretty-printers. | |
19099 | ||
19100 | The auto-loading feature is useful for supplying application-specific | |
19101 | debugging commands and scripts. You can enable or disable this | |
19102 | feature, and view its current state. | |
19103 | ||
19104 | @table @code | |
19105 | @kindex maint set python auto-load | |
19106 | @item maint set python auto-load [yes|no] | |
19107 | Enable or disable the Python auto-loading feature. | |
19108 | ||
19109 | @kindex show python auto-load | |
19110 | @item show python auto-load | |
19111 | Show whether Python auto-loading is enabled or disabled. | |
19112 | @end table | |
19113 | ||
19114 | @value{GDBN} does not track which files it has already auto-loaded. | |
19115 | So, your @samp{-gdb.py} file should take care to ensure that it may be | |
19116 | evaluated multiple times without error. | |
19117 | ||
a08702d6 TJB |
19118 | @node Values From Inferior |
19119 | @subsubsection Values From Inferior | |
19120 | @cindex values from inferior, with Python | |
19121 | @cindex python, working with values from inferior | |
19122 | ||
19123 | @cindex @code{gdb.Value} | |
19124 | @value{GDBN} provides values it obtains from the inferior program in | |
19125 | an object of type @code{gdb.Value}. @value{GDBN} uses this object | |
19126 | for its internal bookkeeping of the inferior's values, and for | |
19127 | fetching values when necessary. | |
19128 | ||
19129 | Inferior values that are simple scalars can be used directly in | |
19130 | Python expressions that are valid for the value's data type. Here's | |
19131 | an example for an integer or floating-point value @code{some_val}: | |
19132 | ||
19133 | @smallexample | |
19134 | bar = some_val + 2 | |
19135 | @end smallexample | |
19136 | ||
19137 | @noindent | |
19138 | As result of this, @code{bar} will also be a @code{gdb.Value} object | |
19139 | whose values are of the same type as those of @code{some_val}. | |
19140 | ||
19141 | Inferior values that are structures or instances of some class can | |
19142 | be accessed using the Python @dfn{dictionary syntax}. For example, if | |
19143 | @code{some_val} is a @code{gdb.Value} instance holding a structure, you | |
19144 | can access its @code{foo} element with: | |
19145 | ||
19146 | @smallexample | |
19147 | bar = some_val['foo'] | |
19148 | @end smallexample | |
19149 | ||
19150 | Again, @code{bar} will also be a @code{gdb.Value} object. | |
19151 | ||
c0c6f777 | 19152 | The following attributes are provided: |
a08702d6 | 19153 | |
def2b000 | 19154 | @table @code |
2c74e833 | 19155 | @defivar Value address |
c0c6f777 TJB |
19156 | If this object is addressable, this read-only attribute holds a |
19157 | @code{gdb.Value} object representing the address. Otherwise, | |
19158 | this attribute holds @code{None}. | |
2c74e833 | 19159 | @end defivar |
c0c6f777 | 19160 | |
def2b000 | 19161 | @cindex optimized out value in Python |
2c74e833 | 19162 | @defivar Value is_optimized_out |
def2b000 TJB |
19163 | This read-only boolean attribute is true if the compiler optimized out |
19164 | this value, thus it is not available for fetching from the inferior. | |
2c74e833 TT |
19165 | @end defivar |
19166 | ||
19167 | @defivar Value type | |
19168 | The type of this @code{gdb.Value}. The value of this attribute is a | |
19169 | @code{gdb.Type} object. | |
19170 | @end defivar | |
def2b000 TJB |
19171 | @end table |
19172 | ||
19173 | The following methods are provided: | |
19174 | ||
19175 | @table @code | |
a08702d6 | 19176 | @defmethod Value dereference |
def2b000 TJB |
19177 | For pointer data types, this method returns a new @code{gdb.Value} object |
19178 | whose contents is the object pointed to by the pointer. For example, if | |
19179 | @code{foo} is a C pointer to an @code{int}, declared in your C program as | |
a08702d6 TJB |
19180 | |
19181 | @smallexample | |
19182 | int *foo; | |
19183 | @end smallexample | |
19184 | ||
19185 | @noindent | |
19186 | then you can use the corresponding @code{gdb.Value} to access what | |
19187 | @code{foo} points to like this: | |
19188 | ||
19189 | @smallexample | |
19190 | bar = foo.dereference () | |
19191 | @end smallexample | |
19192 | ||
19193 | The result @code{bar} will be a @code{gdb.Value} object holding the | |
19194 | value pointed to by @code{foo}. | |
19195 | @end defmethod | |
19196 | ||
fbb8f299 | 19197 | @defmethod Value string @r{[}encoding@r{]} @r{[}errors@r{]} @r{[}length@r{]} |
b6cb8e7d TJB |
19198 | If this @code{gdb.Value} represents a string, then this method |
19199 | converts the contents to a Python string. Otherwise, this method will | |
19200 | throw an exception. | |
19201 | ||
19202 | Strings are recognized in a language-specific way; whether a given | |
19203 | @code{gdb.Value} represents a string is determined by the current | |
19204 | language. | |
19205 | ||
19206 | For C-like languages, a value is a string if it is a pointer to or an | |
19207 | array of characters or ints. The string is assumed to be terminated | |
fbb8f299 PM |
19208 | by a zero of the appropriate width. However if the optional length |
19209 | argument is given, the string will be converted to that given length, | |
19210 | ignoring any embedded zeros that the string may contain. | |
b6cb8e7d TJB |
19211 | |
19212 | If the optional @var{encoding} argument is given, it must be a string | |
19213 | naming the encoding of the string in the @code{gdb.Value}, such as | |
19214 | @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. It accepts | |
19215 | the same encodings as the corresponding argument to Python's | |
19216 | @code{string.decode} method, and the Python codec machinery will be used | |
19217 | to convert the string. If @var{encoding} is not given, or if | |
19218 | @var{encoding} is the empty string, then either the @code{target-charset} | |
19219 | (@pxref{Character Sets}) will be used, or a language-specific encoding | |
19220 | will be used, if the current language is able to supply one. | |
19221 | ||
19222 | The optional @var{errors} argument is the same as the corresponding | |
19223 | argument to Python's @code{string.decode} method. | |
fbb8f299 PM |
19224 | |
19225 | If the optional @var{length} argument is given, the string will be | |
19226 | fetched and converted to the given length. | |
b6cb8e7d | 19227 | @end defmethod |
def2b000 | 19228 | @end table |
b6cb8e7d | 19229 | |
2c74e833 TT |
19230 | @node Types In Python |
19231 | @subsubsection Types In Python | |
19232 | @cindex types in Python | |
19233 | @cindex Python, working with types | |
19234 | ||
19235 | @tindex gdb.Type | |
19236 | @value{GDBN} represents types from the inferior using the class | |
19237 | @code{gdb.Type}. | |
19238 | ||
19239 | The following type-related functions are available in the @code{gdb} | |
19240 | module: | |
19241 | ||
19242 | @findex gdb.lookup_type | |
19243 | @defun lookup_type name [block] | |
19244 | This function looks up a type by name. @var{name} is the name of the | |
19245 | type to look up. It must be a string. | |
19246 | ||
19247 | Ordinarily, this function will return an instance of @code{gdb.Type}. | |
19248 | If the named type cannot be found, it will throw an exception. | |
19249 | @end defun | |
19250 | ||
19251 | An instance of @code{Type} has the following attributes: | |
19252 | ||
19253 | @table @code | |
19254 | @defivar Type code | |
19255 | The type code for this type. The type code will be one of the | |
19256 | @code{TYPE_CODE_} constants defined below. | |
19257 | @end defivar | |
19258 | ||
19259 | @defivar Type sizeof | |
19260 | The size of this type, in target @code{char} units. Usually, a | |
19261 | target's @code{char} type will be an 8-bit byte. However, on some | |
19262 | unusual platforms, this type may have a different size. | |
19263 | @end defivar | |
19264 | ||
19265 | @defivar Type tag | |
19266 | The tag name for this type. The tag name is the name after | |
19267 | @code{struct}, @code{union}, or @code{enum} in C and C@t{++}; not all | |
19268 | languages have this concept. If this type has no tag name, then | |
19269 | @code{None} is returned. | |
19270 | @end defivar | |
19271 | @end table | |
19272 | ||
19273 | The following methods are provided: | |
19274 | ||
19275 | @table @code | |
19276 | @defmethod Type fields | |
19277 | For structure and union types, this method returns the fields. Range | |
19278 | types have two fields, the minimum and maximum values. Enum types | |
19279 | have one field per enum constant. Function and method types have one | |
19280 | field per parameter. The base types of C@t{++} classes are also | |
19281 | represented as fields. If the type has no fields, or does not fit | |
19282 | into one of these categories, an empty sequence will be returned. | |
19283 | ||
19284 | Each field is an object, with some pre-defined attributes: | |
19285 | @table @code | |
19286 | @item bitpos | |
19287 | This attribute is not available for @code{static} fields (as in | |
19288 | C@t{++} or Java). For non-@code{static} fields, the value is the bit | |
19289 | position of the field. | |
19290 | ||
19291 | @item name | |
19292 | The name of the field, or @code{None} for anonymous fields. | |
19293 | ||
19294 | @item artificial | |
19295 | This is @code{True} if the field is artificial, usually meaning that | |
19296 | it was provided by the compiler and not the user. This attribute is | |
19297 | always provided, and is @code{False} if the field is not artificial. | |
19298 | ||
19299 | @item bitsize | |
19300 | If the field is packed, or is a bitfield, then this will have a | |
19301 | non-zero value, which is the size of the field in bits. Otherwise, | |
19302 | this will be zero; in this case the field's size is given by its type. | |
19303 | ||
19304 | @item type | |
19305 | The type of the field. This is usually an instance of @code{Type}, | |
19306 | but it can be @code{None} in some situations. | |
19307 | @end table | |
19308 | @end defmethod | |
19309 | ||
19310 | @defmethod Type const | |
19311 | Return a new @code{gdb.Type} object which represents a | |
19312 | @code{const}-qualified variant of this type. | |
19313 | @end defmethod | |
19314 | ||
19315 | @defmethod Type volatile | |
19316 | Return a new @code{gdb.Type} object which represents a | |
19317 | @code{volatile}-qualified variant of this type. | |
19318 | @end defmethod | |
19319 | ||
19320 | @defmethod Type unqualified | |
19321 | Return a new @code{gdb.Type} object which represents an unqualified | |
19322 | variant of this type. That is, the result is neither @code{const} nor | |
19323 | @code{volatile}. | |
19324 | @end defmethod | |
19325 | ||
19326 | @defmethod Type reference | |
19327 | Return a new @code{gdb.Type} object which represents a reference to this | |
19328 | type. | |
19329 | @end defmethod | |
19330 | ||
19331 | @defmethod Type strip_typedefs | |
19332 | Return a new @code{gdb.Type} that represents the real type, | |
19333 | after removing all layers of typedefs. | |
19334 | @end defmethod | |
19335 | ||
19336 | @defmethod Type target | |
19337 | Return a new @code{gdb.Type} object which represents the target type | |
19338 | of this type. | |
19339 | ||
19340 | For a pointer type, the target type is the type of the pointed-to | |
19341 | object. For an array type (meaning C-like arrays), the target type is | |
19342 | the type of the elements of the array. For a function or method type, | |
19343 | the target type is the type of the return value. For a complex type, | |
19344 | the target type is the type of the elements. For a typedef, the | |
19345 | target type is the aliased type. | |
19346 | ||
19347 | If the type does not have a target, this method will throw an | |
19348 | exception. | |
19349 | @end defmethod | |
19350 | ||
19351 | @defmethod Type template_argument n | |
19352 | If this @code{gdb.Type} is an instantiation of a template, this will | |
19353 | return a new @code{gdb.Type} which represents the type of the | |
19354 | @var{n}th template argument. | |
19355 | ||
19356 | If this @code{gdb.Type} is not a template type, this will throw an | |
19357 | exception. Ordinarily, only C@t{++} code will have template types. | |
19358 | ||
19359 | @var{name} is searched for globally. | |
19360 | @end defmethod | |
19361 | @end table | |
19362 | ||
19363 | ||
19364 | Each type has a code, which indicates what category this type falls | |
19365 | into. The available type categories are represented by constants | |
19366 | defined in the @code{gdb} module: | |
19367 | ||
19368 | @table @code | |
19369 | @findex TYPE_CODE_PTR | |
19370 | @findex gdb.TYPE_CODE_PTR | |
19371 | @item TYPE_CODE_PTR | |
19372 | The type is a pointer. | |
19373 | ||
19374 | @findex TYPE_CODE_ARRAY | |
19375 | @findex gdb.TYPE_CODE_ARRAY | |
19376 | @item TYPE_CODE_ARRAY | |
19377 | The type is an array. | |
19378 | ||
19379 | @findex TYPE_CODE_STRUCT | |
19380 | @findex gdb.TYPE_CODE_STRUCT | |
19381 | @item TYPE_CODE_STRUCT | |
19382 | The type is a structure. | |
19383 | ||
19384 | @findex TYPE_CODE_UNION | |
19385 | @findex gdb.TYPE_CODE_UNION | |
19386 | @item TYPE_CODE_UNION | |
19387 | The type is a union. | |
19388 | ||
19389 | @findex TYPE_CODE_ENUM | |
19390 | @findex gdb.TYPE_CODE_ENUM | |
19391 | @item TYPE_CODE_ENUM | |
19392 | The type is an enum. | |
19393 | ||
19394 | @findex TYPE_CODE_FLAGS | |
19395 | @findex gdb.TYPE_CODE_FLAGS | |
19396 | @item TYPE_CODE_FLAGS | |
19397 | A bit flags type, used for things such as status registers. | |
19398 | ||
19399 | @findex TYPE_CODE_FUNC | |
19400 | @findex gdb.TYPE_CODE_FUNC | |
19401 | @item TYPE_CODE_FUNC | |
19402 | The type is a function. | |
19403 | ||
19404 | @findex TYPE_CODE_INT | |
19405 | @findex gdb.TYPE_CODE_INT | |
19406 | @item TYPE_CODE_INT | |
19407 | The type is an integer type. | |
19408 | ||
19409 | @findex TYPE_CODE_FLT | |
19410 | @findex gdb.TYPE_CODE_FLT | |
19411 | @item TYPE_CODE_FLT | |
19412 | A floating point type. | |
19413 | ||
19414 | @findex TYPE_CODE_VOID | |
19415 | @findex gdb.TYPE_CODE_VOID | |
19416 | @item TYPE_CODE_VOID | |
19417 | The special type @code{void}. | |
19418 | ||
19419 | @findex TYPE_CODE_SET | |
19420 | @findex gdb.TYPE_CODE_SET | |
19421 | @item TYPE_CODE_SET | |
19422 | A Pascal set type. | |
19423 | ||
19424 | @findex TYPE_CODE_RANGE | |
19425 | @findex gdb.TYPE_CODE_RANGE | |
19426 | @item TYPE_CODE_RANGE | |
19427 | A range type, that is, an integer type with bounds. | |
19428 | ||
19429 | @findex TYPE_CODE_STRING | |
19430 | @findex gdb.TYPE_CODE_STRING | |
19431 | @item TYPE_CODE_STRING | |
19432 | A string type. Note that this is only used for certain languages with | |
19433 | language-defined string types; C strings are not represented this way. | |
19434 | ||
19435 | @findex TYPE_CODE_BITSTRING | |
19436 | @findex gdb.TYPE_CODE_BITSTRING | |
19437 | @item TYPE_CODE_BITSTRING | |
19438 | A string of bits. | |
19439 | ||
19440 | @findex TYPE_CODE_ERROR | |
19441 | @findex gdb.TYPE_CODE_ERROR | |
19442 | @item TYPE_CODE_ERROR | |
19443 | An unknown or erroneous type. | |
19444 | ||
19445 | @findex TYPE_CODE_METHOD | |
19446 | @findex gdb.TYPE_CODE_METHOD | |
19447 | @item TYPE_CODE_METHOD | |
19448 | A method type, as found in C@t{++} or Java. | |
19449 | ||
19450 | @findex TYPE_CODE_METHODPTR | |
19451 | @findex gdb.TYPE_CODE_METHODPTR | |
19452 | @item TYPE_CODE_METHODPTR | |
19453 | A pointer-to-member-function. | |
19454 | ||
19455 | @findex TYPE_CODE_MEMBERPTR | |
19456 | @findex gdb.TYPE_CODE_MEMBERPTR | |
19457 | @item TYPE_CODE_MEMBERPTR | |
19458 | A pointer-to-member. | |
19459 | ||
19460 | @findex TYPE_CODE_REF | |
19461 | @findex gdb.TYPE_CODE_REF | |
19462 | @item TYPE_CODE_REF | |
19463 | A reference type. | |
19464 | ||
19465 | @findex TYPE_CODE_CHAR | |
19466 | @findex gdb.TYPE_CODE_CHAR | |
19467 | @item TYPE_CODE_CHAR | |
19468 | A character type. | |
19469 | ||
19470 | @findex TYPE_CODE_BOOL | |
19471 | @findex gdb.TYPE_CODE_BOOL | |
19472 | @item TYPE_CODE_BOOL | |
19473 | A boolean type. | |
19474 | ||
19475 | @findex TYPE_CODE_COMPLEX | |
19476 | @findex gdb.TYPE_CODE_COMPLEX | |
19477 | @item TYPE_CODE_COMPLEX | |
19478 | A complex float type. | |
19479 | ||
19480 | @findex TYPE_CODE_TYPEDEF | |
19481 | @findex gdb.TYPE_CODE_TYPEDEF | |
19482 | @item TYPE_CODE_TYPEDEF | |
19483 | A typedef to some other type. | |
19484 | ||
19485 | @findex TYPE_CODE_NAMESPACE | |
19486 | @findex gdb.TYPE_CODE_NAMESPACE | |
19487 | @item TYPE_CODE_NAMESPACE | |
19488 | A C@t{++} namespace. | |
19489 | ||
19490 | @findex TYPE_CODE_DECFLOAT | |
19491 | @findex gdb.TYPE_CODE_DECFLOAT | |
19492 | @item TYPE_CODE_DECFLOAT | |
19493 | A decimal floating point type. | |
19494 | ||
19495 | @findex TYPE_CODE_INTERNAL_FUNCTION | |
19496 | @findex gdb.TYPE_CODE_INTERNAL_FUNCTION | |
19497 | @item TYPE_CODE_INTERNAL_FUNCTION | |
19498 | A function internal to @value{GDBN}. This is the type used to represent | |
19499 | convenience functions. | |
19500 | @end table | |
19501 | ||
a6bac58e TT |
19502 | @node Pretty Printing |
19503 | @subsubsection Pretty Printing | |
19504 | ||
19505 | @value{GDBN} provides a mechanism to allow pretty-printing of values | |
19506 | using Python code. The pretty-printer API allows application-specific | |
19507 | code to greatly simplify the display of complex objects. This | |
19508 | mechanism works for both MI and the CLI. | |
19509 | ||
19510 | For example, here is how a C@t{++} @code{std::string} looks without a | |
19511 | pretty-printer: | |
19512 | ||
19513 | @smallexample | |
19514 | (@value{GDBP}) print s | |
19515 | $1 = @{ | |
19516 | static npos = 4294967295, | |
19517 | _M_dataplus = @{ | |
19518 | <std::allocator<char>> = @{ | |
19519 | <__gnu_cxx::new_allocator<char>> = @{<No data fields>@}, <No data fields>@}, | |
19520 | members of std::basic_string<char, std::char_traits<char>, std::allocator<char> >::_Alloc_hider: | |
19521 | _M_p = 0x804a014 "abcd" | |
19522 | @} | |
19523 | @} | |
19524 | @end smallexample | |
19525 | ||
19526 | After a pretty-printer for @code{std::string} has been installed, only | |
19527 | the contents are printed: | |
19528 | ||
19529 | @smallexample | |
19530 | (@value{GDBP}) print s | |
19531 | $2 = "abcd" | |
19532 | @end smallexample | |
19533 | ||
19534 | A pretty-printer is just an object that holds a value and implements a | |
19535 | specific interface, defined here. | |
19536 | ||
19537 | @defop Operation {pretty printer} children (self) | |
19538 | @value{GDBN} will call this method on a pretty-printer to compute the | |
19539 | children of the pretty-printer's value. | |
19540 | ||
19541 | This method must return an object conforming to the Python iterator | |
19542 | protocol. Each item returned by the iterator must be a tuple holding | |
19543 | two elements. The first element is the ``name'' of the child; the | |
19544 | second element is the child's value. The value can be any Python | |
19545 | object which is convertible to a @value{GDBN} value. | |
19546 | ||
19547 | This method is optional. If it does not exist, @value{GDBN} will act | |
19548 | as though the value has no children. | |
19549 | @end defop | |
19550 | ||
19551 | @defop Operation {pretty printer} display_hint (self) | |
19552 | The CLI may call this method and use its result to change the | |
19553 | formatting of a value. The result will also be supplied to an MI | |
19554 | consumer as a @samp{displayhint} attribute of the variable being | |
19555 | printed. | |
19556 | ||
19557 | This method is optional. If it does exist, this method must return a | |
19558 | string. | |
19559 | ||
19560 | Some display hints are predefined by @value{GDBN}: | |
19561 | ||
19562 | @table @samp | |
19563 | @item array | |
19564 | Indicate that the object being printed is ``array-like''. The CLI | |
19565 | uses this to respect parameters such as @code{set print elements} and | |
19566 | @code{set print array}. | |
19567 | ||
19568 | @item map | |
19569 | Indicate that the object being printed is ``map-like'', and that the | |
19570 | children of this value can be assumed to alternate between keys and | |
19571 | values. | |
19572 | ||
19573 | @item string | |
19574 | Indicate that the object being printed is ``string-like''. If the | |
19575 | printer's @code{to_string} method returns a Python string of some | |
19576 | kind, then @value{GDBN} will call its internal language-specific | |
19577 | string-printing function to format the string. For the CLI this means | |
19578 | adding quotation marks, possibly escaping some characters, respecting | |
19579 | @code{set print elements}, and the like. | |
19580 | @end table | |
19581 | @end defop | |
19582 | ||
19583 | @defop Operation {pretty printer} to_string (self) | |
19584 | @value{GDBN} will call this method to display the string | |
19585 | representation of the value passed to the object's constructor. | |
19586 | ||
19587 | When printing from the CLI, if the @code{to_string} method exists, | |
19588 | then @value{GDBN} will prepend its result to the values returned by | |
19589 | @code{children}. Exactly how this formatting is done is dependent on | |
19590 | the display hint, and may change as more hints are added. Also, | |
19591 | depending on the print settings (@pxref{Print Settings}), the CLI may | |
19592 | print just the result of @code{to_string} in a stack trace, omitting | |
19593 | the result of @code{children}. | |
19594 | ||
19595 | If this method returns a string, it is printed verbatim. | |
19596 | ||
19597 | Otherwise, if this method returns an instance of @code{gdb.Value}, | |
19598 | then @value{GDBN} prints this value. This may result in a call to | |
19599 | another pretty-printer. | |
19600 | ||
19601 | If instead the method returns a Python value which is convertible to a | |
19602 | @code{gdb.Value}, then @value{GDBN} performs the conversion and prints | |
19603 | the resulting value. Again, this may result in a call to another | |
19604 | pretty-printer. Python scalars (integers, floats, and booleans) and | |
19605 | strings are convertible to @code{gdb.Value}; other types are not. | |
19606 | ||
19607 | If the result is not one of these types, an exception is raised. | |
19608 | @end defop | |
19609 | ||
19610 | @node Selecting Pretty-Printers | |
19611 | @subsubsection Selecting Pretty-Printers | |
19612 | ||
19613 | The Python list @code{gdb.pretty_printers} contains an array of | |
19614 | functions that have been registered via addition as a pretty-printer. | |
19615 | Each @code{gdb.Objfile} also contains a @code{pretty_printers} | |
19616 | attribute. | |
19617 | ||
19618 | A function on one of these lists is passed a single @code{gdb.Value} | |
19619 | argument and should return a pretty-printer object conforming to the | |
19620 | interface definition above (@pxref{Pretty Printing}). If a function | |
19621 | cannot create a pretty-printer for the value, it should return | |
19622 | @code{None}. | |
19623 | ||
19624 | @value{GDBN} first checks the @code{pretty_printers} attribute of each | |
19625 | @code{gdb.Objfile} and iteratively calls each function in the list for | |
19626 | that @code{gdb.Objfile} until it receives a pretty-printer object. | |
19627 | After these lists have been exhausted, it tries the global | |
19628 | @code{gdb.pretty-printers} list, again calling each function until an | |
19629 | object is returned. | |
19630 | ||
19631 | The order in which the objfiles are searched is not specified. For a | |
19632 | given list, functions are always invoked from the head of the list, | |
19633 | and iterated over sequentially until the end of the list, or a printer | |
19634 | object is returned. | |
19635 | ||
19636 | Here is an example showing how a @code{std::string} printer might be | |
19637 | written: | |
19638 | ||
19639 | @smallexample | |
19640 | class StdStringPrinter: | |
19641 | "Print a std::string" | |
19642 | ||
19643 | def __init__ (self, val): | |
19644 | self.val = val | |
19645 | ||
19646 | def to_string (self): | |
19647 | return self.val['_M_dataplus']['_M_p'] | |
19648 | ||
19649 | def display_hint (self): | |
19650 | return 'string' | |
19651 | @end smallexample | |
19652 | ||
19653 | And here is an example showing how a lookup function for the printer | |
19654 | example above might be written. | |
19655 | ||
19656 | @smallexample | |
19657 | def str_lookup_function (val): | |
19658 | ||
19659 | lookup_tag = val.type.tag | |
19660 | regex = re.compile ("^std::basic_string<char,.*>$") | |
19661 | if lookup_tag == None: | |
19662 | return None | |
19663 | if regex.match (lookup_tag): | |
19664 | return StdStringPrinter (val) | |
19665 | ||
19666 | return None | |
19667 | @end smallexample | |
19668 | ||
19669 | The example lookup function extracts the value's type, and attempts to | |
19670 | match it to a type that it can pretty-print. If it is a type the | |
19671 | printer can pretty-print, it will return a printer object. If not, it | |
19672 | returns @code{None}. | |
19673 | ||
19674 | We recommend that you put your core pretty-printers into a Python | |
19675 | package. If your pretty-printers are for use with a library, we | |
19676 | further recommend embedding a version number into the package name. | |
19677 | This practice will enable @value{GDBN} to load multiple versions of | |
19678 | your pretty-printers at the same time, because they will have | |
19679 | different names. | |
19680 | ||
19681 | You should write auto-loaded code (@pxref{Auto-loading}) such that it | |
19682 | can be evaluated multiple times without changing its meaning. An | |
19683 | ideal auto-load file will consist solely of @code{import}s of your | |
19684 | printer modules, followed by a call to a register pretty-printers with | |
19685 | the current objfile. | |
19686 | ||
19687 | Taken as a whole, this approach will scale nicely to multiple | |
19688 | inferiors, each potentially using a different library version. | |
19689 | Embedding a version number in the Python package name will ensure that | |
19690 | @value{GDBN} is able to load both sets of printers simultaneously. | |
19691 | Then, because the search for pretty-printers is done by objfile, and | |
19692 | because your auto-loaded code took care to register your library's | |
19693 | printers with a specific objfile, @value{GDBN} will find the correct | |
19694 | printers for the specific version of the library used by each | |
19695 | inferior. | |
19696 | ||
19697 | To continue the @code{std::string} example (@pxref{Pretty Printing}), | |
19698 | this code might appear in @code{gdb.libstdcxx.v6}: | |
19699 | ||
19700 | @smallexample | |
19701 | def register_printers (objfile): | |
19702 | objfile.pretty_printers.add (str_lookup_function) | |
19703 | @end smallexample | |
19704 | ||
19705 | @noindent | |
19706 | And then the corresponding contents of the auto-load file would be: | |
19707 | ||
19708 | @smallexample | |
19709 | import gdb.libstdcxx.v6 | |
19710 | gdb.libstdcxx.v6.register_printers (gdb.current_objfile ()) | |
19711 | @end smallexample | |
19712 | ||
d8906c6f TJB |
19713 | @node Commands In Python |
19714 | @subsubsection Commands In Python | |
19715 | ||
19716 | @cindex commands in python | |
19717 | @cindex python commands | |
d8906c6f TJB |
19718 | You can implement new @value{GDBN} CLI commands in Python. A CLI |
19719 | command is implemented using an instance of the @code{gdb.Command} | |
19720 | class, most commonly using a subclass. | |
19721 | ||
cc924cad | 19722 | @defmethod Command __init__ name @var{command_class} @r{[}@var{completer_class}@r{]} @r{[}@var{prefix}@r{]} |
d8906c6f TJB |
19723 | The object initializer for @code{Command} registers the new command |
19724 | with @value{GDBN}. This initializer is normally invoked from the | |
19725 | subclass' own @code{__init__} method. | |
19726 | ||
19727 | @var{name} is the name of the command. If @var{name} consists of | |
19728 | multiple words, then the initial words are looked for as prefix | |
19729 | commands. In this case, if one of the prefix commands does not exist, | |
19730 | an exception is raised. | |
19731 | ||
19732 | There is no support for multi-line commands. | |
19733 | ||
cc924cad | 19734 | @var{command_class} should be one of the @samp{COMMAND_} constants |
d8906c6f TJB |
19735 | defined below. This argument tells @value{GDBN} how to categorize the |
19736 | new command in the help system. | |
19737 | ||
cc924cad | 19738 | @var{completer_class} is an optional argument. If given, it should be |
d8906c6f TJB |
19739 | one of the @samp{COMPLETE_} constants defined below. This argument |
19740 | tells @value{GDBN} how to perform completion for this command. If not | |
19741 | given, @value{GDBN} will attempt to complete using the object's | |
19742 | @code{complete} method (see below); if no such method is found, an | |
19743 | error will occur when completion is attempted. | |
19744 | ||
19745 | @var{prefix} is an optional argument. If @code{True}, then the new | |
19746 | command is a prefix command; sub-commands of this command may be | |
19747 | registered. | |
19748 | ||
19749 | The help text for the new command is taken from the Python | |
19750 | documentation string for the command's class, if there is one. If no | |
19751 | documentation string is provided, the default value ``This command is | |
19752 | not documented.'' is used. | |
19753 | @end defmethod | |
19754 | ||
a0c36267 | 19755 | @cindex don't repeat Python command |
d8906c6f TJB |
19756 | @defmethod Command dont_repeat |
19757 | By default, a @value{GDBN} command is repeated when the user enters a | |
19758 | blank line at the command prompt. A command can suppress this | |
19759 | behavior by invoking the @code{dont_repeat} method. This is similar | |
19760 | to the user command @code{dont-repeat}, see @ref{Define, dont-repeat}. | |
19761 | @end defmethod | |
19762 | ||
19763 | @defmethod Command invoke argument from_tty | |
19764 | This method is called by @value{GDBN} when this command is invoked. | |
19765 | ||
19766 | @var{argument} is a string. It is the argument to the command, after | |
19767 | leading and trailing whitespace has been stripped. | |
19768 | ||
19769 | @var{from_tty} is a boolean argument. When true, this means that the | |
19770 | command was entered by the user at the terminal; when false it means | |
19771 | that the command came from elsewhere. | |
19772 | ||
19773 | If this method throws an exception, it is turned into a @value{GDBN} | |
19774 | @code{error} call. Otherwise, the return value is ignored. | |
19775 | @end defmethod | |
19776 | ||
a0c36267 | 19777 | @cindex completion of Python commands |
d8906c6f TJB |
19778 | @defmethod Command complete text word |
19779 | This method is called by @value{GDBN} when the user attempts | |
19780 | completion on this command. All forms of completion are handled by | |
a0c36267 EZ |
19781 | this method, that is, the @key{TAB} and @key{M-?} key bindings |
19782 | (@pxref{Completion}), and the @code{complete} command (@pxref{Help, | |
19783 | complete}). | |
d8906c6f TJB |
19784 | |
19785 | The arguments @var{text} and @var{word} are both strings. @var{text} | |
19786 | holds the complete command line up to the cursor's location. | |
19787 | @var{word} holds the last word of the command line; this is computed | |
19788 | using a word-breaking heuristic. | |
19789 | ||
19790 | The @code{complete} method can return several values: | |
19791 | @itemize @bullet | |
19792 | @item | |
19793 | If the return value is a sequence, the contents of the sequence are | |
19794 | used as the completions. It is up to @code{complete} to ensure that the | |
19795 | contents actually do complete the word. A zero-length sequence is | |
19796 | allowed, it means that there were no completions available. Only | |
19797 | string elements of the sequence are used; other elements in the | |
19798 | sequence are ignored. | |
19799 | ||
19800 | @item | |
19801 | If the return value is one of the @samp{COMPLETE_} constants defined | |
19802 | below, then the corresponding @value{GDBN}-internal completion | |
19803 | function is invoked, and its result is used. | |
19804 | ||
19805 | @item | |
19806 | All other results are treated as though there were no available | |
19807 | completions. | |
19808 | @end itemize | |
19809 | @end defmethod | |
19810 | ||
d8906c6f TJB |
19811 | When a new command is registered, it must be declared as a member of |
19812 | some general class of commands. This is used to classify top-level | |
19813 | commands in the on-line help system; note that prefix commands are not | |
19814 | listed under their own category but rather that of their top-level | |
19815 | command. The available classifications are represented by constants | |
19816 | defined in the @code{gdb} module: | |
19817 | ||
19818 | @table @code | |
19819 | @findex COMMAND_NONE | |
19820 | @findex gdb.COMMAND_NONE | |
19821 | @item COMMAND_NONE | |
19822 | The command does not belong to any particular class. A command in | |
19823 | this category will not be displayed in any of the help categories. | |
19824 | ||
19825 | @findex COMMAND_RUNNING | |
19826 | @findex gdb.COMMAND_RUNNING | |
a0c36267 | 19827 | @item COMMAND_RUNNING |
d8906c6f TJB |
19828 | The command is related to running the inferior. For example, |
19829 | @code{start}, @code{step}, and @code{continue} are in this category. | |
a0c36267 | 19830 | Type @kbd{help running} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
19831 | commands in this category. |
19832 | ||
19833 | @findex COMMAND_DATA | |
19834 | @findex gdb.COMMAND_DATA | |
a0c36267 | 19835 | @item COMMAND_DATA |
d8906c6f TJB |
19836 | The command is related to data or variables. For example, |
19837 | @code{call}, @code{find}, and @code{print} are in this category. Type | |
a0c36267 | 19838 | @kbd{help data} at the @value{GDBN} prompt to see a list of commands |
d8906c6f TJB |
19839 | in this category. |
19840 | ||
19841 | @findex COMMAND_STACK | |
19842 | @findex gdb.COMMAND_STACK | |
19843 | @item COMMAND_STACK | |
19844 | The command has to do with manipulation of the stack. For example, | |
19845 | @code{backtrace}, @code{frame}, and @code{return} are in this | |
a0c36267 | 19846 | category. Type @kbd{help stack} at the @value{GDBN} prompt to see a |
d8906c6f TJB |
19847 | list of commands in this category. |
19848 | ||
19849 | @findex COMMAND_FILES | |
19850 | @findex gdb.COMMAND_FILES | |
19851 | @item COMMAND_FILES | |
19852 | This class is used for file-related commands. For example, | |
19853 | @code{file}, @code{list} and @code{section} are in this category. | |
a0c36267 | 19854 | Type @kbd{help files} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
19855 | commands in this category. |
19856 | ||
19857 | @findex COMMAND_SUPPORT | |
19858 | @findex gdb.COMMAND_SUPPORT | |
19859 | @item COMMAND_SUPPORT | |
19860 | This should be used for ``support facilities'', generally meaning | |
19861 | things that are useful to the user when interacting with @value{GDBN}, | |
19862 | but not related to the state of the inferior. For example, | |
19863 | @code{help}, @code{make}, and @code{shell} are in this category. Type | |
a0c36267 | 19864 | @kbd{help support} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
19865 | commands in this category. |
19866 | ||
19867 | @findex COMMAND_STATUS | |
19868 | @findex gdb.COMMAND_STATUS | |
a0c36267 | 19869 | @item COMMAND_STATUS |
d8906c6f TJB |
19870 | The command is an @samp{info}-related command, that is, related to the |
19871 | state of @value{GDBN} itself. For example, @code{info}, @code{macro}, | |
a0c36267 | 19872 | and @code{show} are in this category. Type @kbd{help status} at the |
d8906c6f TJB |
19873 | @value{GDBN} prompt to see a list of commands in this category. |
19874 | ||
19875 | @findex COMMAND_BREAKPOINTS | |
19876 | @findex gdb.COMMAND_BREAKPOINTS | |
a0c36267 | 19877 | @item COMMAND_BREAKPOINTS |
d8906c6f | 19878 | The command has to do with breakpoints. For example, @code{break}, |
a0c36267 | 19879 | @code{clear}, and @code{delete} are in this category. Type @kbd{help |
d8906c6f TJB |
19880 | breakpoints} at the @value{GDBN} prompt to see a list of commands in |
19881 | this category. | |
19882 | ||
19883 | @findex COMMAND_TRACEPOINTS | |
19884 | @findex gdb.COMMAND_TRACEPOINTS | |
a0c36267 | 19885 | @item COMMAND_TRACEPOINTS |
d8906c6f TJB |
19886 | The command has to do with tracepoints. For example, @code{trace}, |
19887 | @code{actions}, and @code{tfind} are in this category. Type | |
a0c36267 | 19888 | @kbd{help tracepoints} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
19889 | commands in this category. |
19890 | ||
19891 | @findex COMMAND_OBSCURE | |
19892 | @findex gdb.COMMAND_OBSCURE | |
19893 | @item COMMAND_OBSCURE | |
19894 | The command is only used in unusual circumstances, or is not of | |
19895 | general interest to users. For example, @code{checkpoint}, | |
a0c36267 | 19896 | @code{fork}, and @code{stop} are in this category. Type @kbd{help |
d8906c6f TJB |
19897 | obscure} at the @value{GDBN} prompt to see a list of commands in this |
19898 | category. | |
19899 | ||
19900 | @findex COMMAND_MAINTENANCE | |
19901 | @findex gdb.COMMAND_MAINTENANCE | |
19902 | @item COMMAND_MAINTENANCE | |
19903 | The command is only useful to @value{GDBN} maintainers. The | |
19904 | @code{maintenance} and @code{flushregs} commands are in this category. | |
a0c36267 | 19905 | Type @kbd{help internals} at the @value{GDBN} prompt to see a list of |
d8906c6f TJB |
19906 | commands in this category. |
19907 | @end table | |
19908 | ||
d8906c6f TJB |
19909 | A new command can use a predefined completion function, either by |
19910 | specifying it via an argument at initialization, or by returning it | |
19911 | from the @code{complete} method. These predefined completion | |
19912 | constants are all defined in the @code{gdb} module: | |
19913 | ||
19914 | @table @code | |
19915 | @findex COMPLETE_NONE | |
19916 | @findex gdb.COMPLETE_NONE | |
19917 | @item COMPLETE_NONE | |
19918 | This constant means that no completion should be done. | |
19919 | ||
19920 | @findex COMPLETE_FILENAME | |
19921 | @findex gdb.COMPLETE_FILENAME | |
19922 | @item COMPLETE_FILENAME | |
19923 | This constant means that filename completion should be performed. | |
19924 | ||
19925 | @findex COMPLETE_LOCATION | |
19926 | @findex gdb.COMPLETE_LOCATION | |
19927 | @item COMPLETE_LOCATION | |
19928 | This constant means that location completion should be done. | |
19929 | @xref{Specify Location}. | |
19930 | ||
19931 | @findex COMPLETE_COMMAND | |
19932 | @findex gdb.COMPLETE_COMMAND | |
19933 | @item COMPLETE_COMMAND | |
19934 | This constant means that completion should examine @value{GDBN} | |
19935 | command names. | |
19936 | ||
19937 | @findex COMPLETE_SYMBOL | |
19938 | @findex gdb.COMPLETE_SYMBOL | |
19939 | @item COMPLETE_SYMBOL | |
19940 | This constant means that completion should be done using symbol names | |
19941 | as the source. | |
19942 | @end table | |
19943 | ||
19944 | The following code snippet shows how a trivial CLI command can be | |
19945 | implemented in Python: | |
19946 | ||
19947 | @smallexample | |
19948 | class HelloWorld (gdb.Command): | |
19949 | """Greet the whole world.""" | |
19950 | ||
19951 | def __init__ (self): | |
19952 | super (HelloWorld, self).__init__ ("hello-world", gdb.COMMAND_OBSCURE) | |
19953 | ||
19954 | def invoke (self, arg, from_tty): | |
19955 | print "Hello, World!" | |
19956 | ||
19957 | HelloWorld () | |
19958 | @end smallexample | |
19959 | ||
19960 | The last line instantiates the class, and is necessary to trigger the | |
19961 | registration of the command with @value{GDBN}. Depending on how the | |
19962 | Python code is read into @value{GDBN}, you may need to import the | |
19963 | @code{gdb} module explicitly. | |
19964 | ||
bc3b79fd TJB |
19965 | @node Functions In Python |
19966 | @subsubsection Writing new convenience functions | |
19967 | ||
19968 | @cindex writing convenience functions | |
19969 | @cindex convenience functions in python | |
19970 | @cindex python convenience functions | |
19971 | @tindex gdb.Function | |
19972 | @tindex Function | |
19973 | You can implement new convenience functions (@pxref{Convenience Vars}) | |
19974 | in Python. A convenience function is an instance of a subclass of the | |
19975 | class @code{gdb.Function}. | |
19976 | ||
19977 | @defmethod Function __init__ name | |
19978 | The initializer for @code{Function} registers the new function with | |
19979 | @value{GDBN}. The argument @var{name} is the name of the function, | |
19980 | a string. The function will be visible to the user as a convenience | |
19981 | variable of type @code{internal function}, whose name is the same as | |
19982 | the given @var{name}. | |
19983 | ||
19984 | The documentation for the new function is taken from the documentation | |
19985 | string for the new class. | |
19986 | @end defmethod | |
19987 | ||
19988 | @defmethod Function invoke @var{*args} | |
19989 | When a convenience function is evaluated, its arguments are converted | |
19990 | to instances of @code{gdb.Value}, and then the function's | |
19991 | @code{invoke} method is called. Note that @value{GDBN} does not | |
19992 | predetermine the arity of convenience functions. Instead, all | |
19993 | available arguments are passed to @code{invoke}, following the | |
19994 | standard Python calling convention. In particular, a convenience | |
19995 | function can have default values for parameters without ill effect. | |
19996 | ||
19997 | The return value of this method is used as its value in the enclosing | |
19998 | expression. If an ordinary Python value is returned, it is converted | |
19999 | to a @code{gdb.Value} following the usual rules. | |
20000 | @end defmethod | |
20001 | ||
20002 | The following code snippet shows how a trivial convenience function can | |
20003 | be implemented in Python: | |
20004 | ||
20005 | @smallexample | |
20006 | class Greet (gdb.Function): | |
20007 | """Return string to greet someone. | |
20008 | Takes a name as argument.""" | |
20009 | ||
20010 | def __init__ (self): | |
20011 | super (Greet, self).__init__ ("greet") | |
20012 | ||
20013 | def invoke (self, name): | |
20014 | return "Hello, %s!" % name.string () | |
20015 | ||
20016 | Greet () | |
20017 | @end smallexample | |
20018 | ||
20019 | The last line instantiates the class, and is necessary to trigger the | |
20020 | registration of the function with @value{GDBN}. Depending on how the | |
20021 | Python code is read into @value{GDBN}, you may need to import the | |
20022 | @code{gdb} module explicitly. | |
20023 | ||
89c73ade TT |
20024 | @node Objfiles In Python |
20025 | @subsubsection Objfiles In Python | |
20026 | ||
20027 | @cindex objfiles in python | |
20028 | @tindex gdb.Objfile | |
20029 | @tindex Objfile | |
20030 | @value{GDBN} loads symbols for an inferior from various | |
20031 | symbol-containing files (@pxref{Files}). These include the primary | |
20032 | executable file, any shared libraries used by the inferior, and any | |
20033 | separate debug info files (@pxref{Separate Debug Files}). | |
20034 | @value{GDBN} calls these symbol-containing files @dfn{objfiles}. | |
20035 | ||
20036 | The following objfile-related functions are available in the | |
20037 | @code{gdb} module: | |
20038 | ||
20039 | @findex gdb.current_objfile | |
20040 | @defun current_objfile | |
20041 | When auto-loading a Python script (@pxref{Auto-loading}), @value{GDBN} | |
20042 | sets the ``current objfile'' to the corresponding objfile. This | |
20043 | function returns the current objfile. If there is no current objfile, | |
20044 | this function returns @code{None}. | |
20045 | @end defun | |
20046 | ||
20047 | @findex gdb.objfiles | |
20048 | @defun objfiles | |
20049 | Return a sequence of all the objfiles current known to @value{GDBN}. | |
20050 | @xref{Objfiles In Python}. | |
20051 | @end defun | |
20052 | ||
20053 | Each objfile is represented by an instance of the @code{gdb.Objfile} | |
20054 | class. | |
20055 | ||
20056 | @defivar Objfile filename | |
20057 | The file name of the objfile as a string. | |
20058 | @end defivar | |
20059 | ||
20060 | @defivar Objfile pretty_printers | |
20061 | The @code{pretty_printers} attribute is a list of functions. It is | |
20062 | used to look up pretty-printers. A @code{Value} is passed to each | |
20063 | function in order; if the function returns @code{None}, then the | |
20064 | search continues. Otherwise, the return value should be an object | |
a6bac58e TT |
20065 | which is used to format the value. @xref{Pretty Printing}, for more |
20066 | information. | |
89c73ade TT |
20067 | @end defivar |
20068 | ||
f8f6f20b TJB |
20069 | @node Frames In Python |
20070 | @subsubsection Acessing inferior stack frames from Python. | |
20071 | ||
20072 | @cindex frames in python | |
20073 | When the debugged program stops, @value{GDBN} is able to analyze its call | |
20074 | stack (@pxref{Frames,,Stack frames}). The @code{gdb.Frame} class | |
20075 | represents a frame in the stack. A @code{gdb.Frame} object is only valid | |
20076 | while its corresponding frame exists in the inferior's stack. If you try | |
20077 | to use an invalid frame object, @value{GDBN} will throw a @code{RuntimeError} | |
20078 | exception. | |
20079 | ||
20080 | Two @code{gdb.Frame} objects can be compared for equality with the @code{==} | |
20081 | operator, like: | |
20082 | ||
20083 | @smallexample | |
20084 | (@value{GDBP}) python print gdb.newest_frame() == gdb.selected_frame () | |
20085 | True | |
20086 | @end smallexample | |
20087 | ||
20088 | The following frame-related functions are available in the @code{gdb} module: | |
20089 | ||
20090 | @findex gdb.selected_frame | |
20091 | @defun selected_frame | |
20092 | Return the selected frame object. (@pxref{Selection,,Selecting a Frame}). | |
20093 | @end defun | |
20094 | ||
20095 | @defun frame_stop_reason_string reason | |
20096 | Return a string explaining the reason why @value{GDBN} stopped unwinding | |
20097 | frames, as expressed by the given @var{reason} code (an integer, see the | |
20098 | @code{unwind_stop_reason} method further down in this section). | |
20099 | @end defun | |
20100 | ||
20101 | A @code{gdb.Frame} object has the following methods: | |
20102 | ||
20103 | @table @code | |
20104 | @defmethod Frame is_valid | |
20105 | Returns true if the @code{gdb.Frame} object is valid, false if not. | |
20106 | A frame object can become invalid if the frame it refers to doesn't | |
20107 | exist anymore in the inferior. All @code{gdb.Frame} methods will throw | |
20108 | an exception if it is invalid at the time the method is called. | |
20109 | @end defmethod | |
20110 | ||
20111 | @defmethod Frame name | |
20112 | Returns the function name of the frame, or @code{None} if it can't be | |
20113 | obtained. | |
20114 | @end defmethod | |
20115 | ||
20116 | @defmethod Frame type | |
20117 | Returns the type of the frame. The value can be one of | |
20118 | @code{gdb.NORMAL_FRAME}, @code{gdb.DUMMY_FRAME}, @code{gdb.SIGTRAMP_FRAME} | |
20119 | or @code{gdb.SENTINEL_FRAME}. | |
20120 | @end defmethod | |
20121 | ||
20122 | @defmethod Frame unwind_stop_reason | |
20123 | Return an integer representing the reason why it's not possible to find | |
20124 | more frames toward the outermost frame. Use | |
20125 | @code{gdb.frame_stop_reason_string} to convert the value returned by this | |
20126 | function to a string. | |
20127 | @end defmethod | |
20128 | ||
20129 | @defmethod Frame pc | |
20130 | Returns the frame's resume address. | |
20131 | @end defmethod | |
20132 | ||
20133 | @defmethod Frame older | |
20134 | Return the frame that called this frame. | |
20135 | @end defmethod | |
20136 | ||
20137 | @defmethod Frame newer | |
20138 | Return the frame called by this frame. | |
20139 | @end defmethod | |
20140 | ||
20141 | @defmethod Frame read_var variable | |
20142 | Return the value of the given variable in this frame. @var{variable} must | |
20143 | be a string. | |
20144 | @end defmethod | |
20145 | @end table | |
20146 | ||
21c294e6 AC |
20147 | @node Interpreters |
20148 | @chapter Command Interpreters | |
20149 | @cindex command interpreters | |
20150 | ||
20151 | @value{GDBN} supports multiple command interpreters, and some command | |
20152 | infrastructure to allow users or user interface writers to switch | |
20153 | between interpreters or run commands in other interpreters. | |
20154 | ||
20155 | @value{GDBN} currently supports two command interpreters, the console | |
20156 | interpreter (sometimes called the command-line interpreter or @sc{cli}) | |
20157 | and the machine interface interpreter (or @sc{gdb/mi}). This manual | |
20158 | describes both of these interfaces in great detail. | |
20159 | ||
20160 | By default, @value{GDBN} will start with the console interpreter. | |
20161 | However, the user may choose to start @value{GDBN} with another | |
20162 | interpreter by specifying the @option{-i} or @option{--interpreter} | |
20163 | startup options. Defined interpreters include: | |
20164 | ||
20165 | @table @code | |
20166 | @item console | |
20167 | @cindex console interpreter | |
20168 | The traditional console or command-line interpreter. This is the most often | |
20169 | used interpreter with @value{GDBN}. With no interpreter specified at runtime, | |
20170 | @value{GDBN} will use this interpreter. | |
20171 | ||
20172 | @item mi | |
20173 | @cindex mi interpreter | |
20174 | The newest @sc{gdb/mi} interface (currently @code{mi2}). Used primarily | |
20175 | by programs wishing to use @value{GDBN} as a backend for a debugger GUI | |
20176 | or an IDE. For more information, see @ref{GDB/MI, ,The @sc{gdb/mi} | |
20177 | Interface}. | |
20178 | ||
20179 | @item mi2 | |
20180 | @cindex mi2 interpreter | |
20181 | The current @sc{gdb/mi} interface. | |
20182 | ||
20183 | @item mi1 | |
20184 | @cindex mi1 interpreter | |
20185 | The @sc{gdb/mi} interface included in @value{GDBN} 5.1, 5.2, and 5.3. | |
20186 | ||
20187 | @end table | |
20188 | ||
20189 | @cindex invoke another interpreter | |
20190 | The interpreter being used by @value{GDBN} may not be dynamically | |
20191 | switched at runtime. Although possible, this could lead to a very | |
20192 | precarious situation. Consider an IDE using @sc{gdb/mi}. If a user | |
20193 | enters the command "interpreter-set console" in a console view, | |
20194 | @value{GDBN} would switch to using the console interpreter, rendering | |
20195 | the IDE inoperable! | |
20196 | ||
20197 | @kindex interpreter-exec | |
20198 | Although you may only choose a single interpreter at startup, you may execute | |
20199 | commands in any interpreter from the current interpreter using the appropriate | |
20200 | command. If you are running the console interpreter, simply use the | |
20201 | @code{interpreter-exec} command: | |
20202 | ||
20203 | @smallexample | |
20204 | interpreter-exec mi "-data-list-register-names" | |
20205 | @end smallexample | |
20206 | ||
20207 | @sc{gdb/mi} has a similar command, although it is only available in versions of | |
20208 | @value{GDBN} which support @sc{gdb/mi} version 2 (or greater). | |
20209 | ||
8e04817f AC |
20210 | @node TUI |
20211 | @chapter @value{GDBN} Text User Interface | |
20212 | @cindex TUI | |
d0d5df6f | 20213 | @cindex Text User Interface |
c906108c | 20214 | |
8e04817f AC |
20215 | @menu |
20216 | * TUI Overview:: TUI overview | |
20217 | * TUI Keys:: TUI key bindings | |
7cf36c78 | 20218 | * TUI Single Key Mode:: TUI single key mode |
db2e3e2e | 20219 | * TUI Commands:: TUI-specific commands |
8e04817f AC |
20220 | * TUI Configuration:: TUI configuration variables |
20221 | @end menu | |
c906108c | 20222 | |
46ba6afa | 20223 | The @value{GDBN} Text User Interface (TUI) is a terminal |
d0d5df6f AC |
20224 | interface which uses the @code{curses} library to show the source |
20225 | file, the assembly output, the program registers and @value{GDBN} | |
46ba6afa BW |
20226 | commands in separate text windows. The TUI mode is supported only |
20227 | on platforms where a suitable version of the @code{curses} library | |
20228 | is available. | |
d0d5df6f | 20229 | |
46ba6afa BW |
20230 | @pindex @value{GDBTUI} |
20231 | The TUI mode is enabled by default when you invoke @value{GDBN} as | |
20232 | either @samp{@value{GDBTUI}} or @samp{@value{GDBP} -tui}. | |
20233 | You can also switch in and out of TUI mode while @value{GDBN} runs by | |
20234 | using various TUI commands and key bindings, such as @kbd{C-x C-a}. | |
20235 | @xref{TUI Keys, ,TUI Key Bindings}. | |
c906108c | 20236 | |
8e04817f | 20237 | @node TUI Overview |
79a6e687 | 20238 | @section TUI Overview |
c906108c | 20239 | |
46ba6afa | 20240 | In TUI mode, @value{GDBN} can display several text windows: |
c906108c | 20241 | |
8e04817f AC |
20242 | @table @emph |
20243 | @item command | |
20244 | This window is the @value{GDBN} command window with the @value{GDBN} | |
46ba6afa BW |
20245 | prompt and the @value{GDBN} output. The @value{GDBN} input is still |
20246 | managed using readline. | |
c906108c | 20247 | |
8e04817f AC |
20248 | @item source |
20249 | The source window shows the source file of the program. The current | |
46ba6afa | 20250 | line and active breakpoints are displayed in this window. |
c906108c | 20251 | |
8e04817f AC |
20252 | @item assembly |
20253 | The assembly window shows the disassembly output of the program. | |
c906108c | 20254 | |
8e04817f | 20255 | @item register |
46ba6afa BW |
20256 | This window shows the processor registers. Registers are highlighted |
20257 | when their values change. | |
c906108c SS |
20258 | @end table |
20259 | ||
269c21fe | 20260 | The source and assembly windows show the current program position |
46ba6afa BW |
20261 | by highlighting the current line and marking it with a @samp{>} marker. |
20262 | Breakpoints are indicated with two markers. The first marker | |
269c21fe SC |
20263 | indicates the breakpoint type: |
20264 | ||
20265 | @table @code | |
20266 | @item B | |
20267 | Breakpoint which was hit at least once. | |
20268 | ||
20269 | @item b | |
20270 | Breakpoint which was never hit. | |
20271 | ||
20272 | @item H | |
20273 | Hardware breakpoint which was hit at least once. | |
20274 | ||
20275 | @item h | |
20276 | Hardware breakpoint which was never hit. | |
269c21fe SC |
20277 | @end table |
20278 | ||
20279 | The second marker indicates whether the breakpoint is enabled or not: | |
20280 | ||
20281 | @table @code | |
20282 | @item + | |
20283 | Breakpoint is enabled. | |
20284 | ||
20285 | @item - | |
20286 | Breakpoint is disabled. | |
269c21fe SC |
20287 | @end table |
20288 | ||
46ba6afa BW |
20289 | The source, assembly and register windows are updated when the current |
20290 | thread changes, when the frame changes, or when the program counter | |
20291 | changes. | |
20292 | ||
20293 | These windows are not all visible at the same time. The command | |
20294 | window is always visible. The others can be arranged in several | |
20295 | layouts: | |
c906108c | 20296 | |
8e04817f AC |
20297 | @itemize @bullet |
20298 | @item | |
46ba6afa | 20299 | source only, |
2df3850c | 20300 | |
8e04817f | 20301 | @item |
46ba6afa | 20302 | assembly only, |
8e04817f AC |
20303 | |
20304 | @item | |
46ba6afa | 20305 | source and assembly, |
8e04817f AC |
20306 | |
20307 | @item | |
46ba6afa | 20308 | source and registers, or |
c906108c | 20309 | |
8e04817f | 20310 | @item |
46ba6afa | 20311 | assembly and registers. |
8e04817f | 20312 | @end itemize |
c906108c | 20313 | |
46ba6afa | 20314 | A status line above the command window shows the following information: |
b7bb15bc SC |
20315 | |
20316 | @table @emph | |
20317 | @item target | |
46ba6afa | 20318 | Indicates the current @value{GDBN} target. |
b7bb15bc SC |
20319 | (@pxref{Targets, ,Specifying a Debugging Target}). |
20320 | ||
20321 | @item process | |
46ba6afa | 20322 | Gives the current process or thread number. |
b7bb15bc SC |
20323 | When no process is being debugged, this field is set to @code{No process}. |
20324 | ||
20325 | @item function | |
20326 | Gives the current function name for the selected frame. | |
20327 | The name is demangled if demangling is turned on (@pxref{Print Settings}). | |
46ba6afa | 20328 | When there is no symbol corresponding to the current program counter, |
b7bb15bc SC |
20329 | the string @code{??} is displayed. |
20330 | ||
20331 | @item line | |
20332 | Indicates the current line number for the selected frame. | |
46ba6afa | 20333 | When the current line number is not known, the string @code{??} is displayed. |
b7bb15bc SC |
20334 | |
20335 | @item pc | |
20336 | Indicates the current program counter address. | |
b7bb15bc SC |
20337 | @end table |
20338 | ||
8e04817f AC |
20339 | @node TUI Keys |
20340 | @section TUI Key Bindings | |
20341 | @cindex TUI key bindings | |
c906108c | 20342 | |
8e04817f | 20343 | The TUI installs several key bindings in the readline keymaps |
46ba6afa | 20344 | (@pxref{Command Line Editing}). The following key bindings |
8e04817f | 20345 | are installed for both TUI mode and the @value{GDBN} standard mode. |
c906108c | 20346 | |
8e04817f AC |
20347 | @table @kbd |
20348 | @kindex C-x C-a | |
20349 | @item C-x C-a | |
20350 | @kindex C-x a | |
20351 | @itemx C-x a | |
20352 | @kindex C-x A | |
20353 | @itemx C-x A | |
46ba6afa BW |
20354 | Enter or leave the TUI mode. When leaving the TUI mode, |
20355 | the curses window management stops and @value{GDBN} operates using | |
20356 | its standard mode, writing on the terminal directly. When reentering | |
20357 | the TUI mode, control is given back to the curses windows. | |
8e04817f | 20358 | The screen is then refreshed. |
c906108c | 20359 | |
8e04817f AC |
20360 | @kindex C-x 1 |
20361 | @item C-x 1 | |
20362 | Use a TUI layout with only one window. The layout will | |
20363 | either be @samp{source} or @samp{assembly}. When the TUI mode | |
20364 | is not active, it will switch to the TUI mode. | |
2df3850c | 20365 | |
8e04817f | 20366 | Think of this key binding as the Emacs @kbd{C-x 1} binding. |
c906108c | 20367 | |
8e04817f AC |
20368 | @kindex C-x 2 |
20369 | @item C-x 2 | |
20370 | Use a TUI layout with at least two windows. When the current | |
46ba6afa | 20371 | layout already has two windows, the next layout with two windows is used. |
8e04817f AC |
20372 | When a new layout is chosen, one window will always be common to the |
20373 | previous layout and the new one. | |
c906108c | 20374 | |
8e04817f | 20375 | Think of it as the Emacs @kbd{C-x 2} binding. |
2df3850c | 20376 | |
72ffddc9 SC |
20377 | @kindex C-x o |
20378 | @item C-x o | |
20379 | Change the active window. The TUI associates several key bindings | |
46ba6afa | 20380 | (like scrolling and arrow keys) with the active window. This command |
72ffddc9 SC |
20381 | gives the focus to the next TUI window. |
20382 | ||
20383 | Think of it as the Emacs @kbd{C-x o} binding. | |
20384 | ||
7cf36c78 SC |
20385 | @kindex C-x s |
20386 | @item C-x s | |
46ba6afa BW |
20387 | Switch in and out of the TUI SingleKey mode that binds single |
20388 | keys to @value{GDBN} commands (@pxref{TUI Single Key Mode}). | |
c906108c SS |
20389 | @end table |
20390 | ||
46ba6afa | 20391 | The following key bindings only work in the TUI mode: |
5d161b24 | 20392 | |
46ba6afa | 20393 | @table @asis |
8e04817f | 20394 | @kindex PgUp |
46ba6afa | 20395 | @item @key{PgUp} |
8e04817f | 20396 | Scroll the active window one page up. |
c906108c | 20397 | |
8e04817f | 20398 | @kindex PgDn |
46ba6afa | 20399 | @item @key{PgDn} |
8e04817f | 20400 | Scroll the active window one page down. |
c906108c | 20401 | |
8e04817f | 20402 | @kindex Up |
46ba6afa | 20403 | @item @key{Up} |
8e04817f | 20404 | Scroll the active window one line up. |
c906108c | 20405 | |
8e04817f | 20406 | @kindex Down |
46ba6afa | 20407 | @item @key{Down} |
8e04817f | 20408 | Scroll the active window one line down. |
c906108c | 20409 | |
8e04817f | 20410 | @kindex Left |
46ba6afa | 20411 | @item @key{Left} |
8e04817f | 20412 | Scroll the active window one column left. |
c906108c | 20413 | |
8e04817f | 20414 | @kindex Right |
46ba6afa | 20415 | @item @key{Right} |
8e04817f | 20416 | Scroll the active window one column right. |
c906108c | 20417 | |
8e04817f | 20418 | @kindex C-L |
46ba6afa | 20419 | @item @kbd{C-L} |
8e04817f | 20420 | Refresh the screen. |
8e04817f | 20421 | @end table |
c906108c | 20422 | |
46ba6afa BW |
20423 | Because the arrow keys scroll the active window in the TUI mode, they |
20424 | are not available for their normal use by readline unless the command | |
20425 | window has the focus. When another window is active, you must use | |
20426 | other readline key bindings such as @kbd{C-p}, @kbd{C-n}, @kbd{C-b} | |
20427 | and @kbd{C-f} to control the command window. | |
8e04817f | 20428 | |
7cf36c78 SC |
20429 | @node TUI Single Key Mode |
20430 | @section TUI Single Key Mode | |
20431 | @cindex TUI single key mode | |
20432 | ||
46ba6afa BW |
20433 | The TUI also provides a @dfn{SingleKey} mode, which binds several |
20434 | frequently used @value{GDBN} commands to single keys. Type @kbd{C-x s} to | |
20435 | switch into this mode, where the following key bindings are used: | |
7cf36c78 SC |
20436 | |
20437 | @table @kbd | |
20438 | @kindex c @r{(SingleKey TUI key)} | |
20439 | @item c | |
20440 | continue | |
20441 | ||
20442 | @kindex d @r{(SingleKey TUI key)} | |
20443 | @item d | |
20444 | down | |
20445 | ||
20446 | @kindex f @r{(SingleKey TUI key)} | |
20447 | @item f | |
20448 | finish | |
20449 | ||
20450 | @kindex n @r{(SingleKey TUI key)} | |
20451 | @item n | |
20452 | next | |
20453 | ||
20454 | @kindex q @r{(SingleKey TUI key)} | |
20455 | @item q | |
46ba6afa | 20456 | exit the SingleKey mode. |
7cf36c78 SC |
20457 | |
20458 | @kindex r @r{(SingleKey TUI key)} | |
20459 | @item r | |
20460 | run | |
20461 | ||
20462 | @kindex s @r{(SingleKey TUI key)} | |
20463 | @item s | |
20464 | step | |
20465 | ||
20466 | @kindex u @r{(SingleKey TUI key)} | |
20467 | @item u | |
20468 | up | |
20469 | ||
20470 | @kindex v @r{(SingleKey TUI key)} | |
20471 | @item v | |
20472 | info locals | |
20473 | ||
20474 | @kindex w @r{(SingleKey TUI key)} | |
20475 | @item w | |
20476 | where | |
7cf36c78 SC |
20477 | @end table |
20478 | ||
20479 | Other keys temporarily switch to the @value{GDBN} command prompt. | |
20480 | The key that was pressed is inserted in the editing buffer so that | |
20481 | it is possible to type most @value{GDBN} commands without interaction | |
46ba6afa BW |
20482 | with the TUI SingleKey mode. Once the command is entered the TUI |
20483 | SingleKey mode is restored. The only way to permanently leave | |
7f9087cb | 20484 | this mode is by typing @kbd{q} or @kbd{C-x s}. |
7cf36c78 SC |
20485 | |
20486 | ||
8e04817f | 20487 | @node TUI Commands |
db2e3e2e | 20488 | @section TUI-specific Commands |
8e04817f AC |
20489 | @cindex TUI commands |
20490 | ||
20491 | The TUI has specific commands to control the text windows. | |
46ba6afa BW |
20492 | These commands are always available, even when @value{GDBN} is not in |
20493 | the TUI mode. When @value{GDBN} is in the standard mode, most | |
20494 | of these commands will automatically switch to the TUI mode. | |
c906108c SS |
20495 | |
20496 | @table @code | |
3d757584 SC |
20497 | @item info win |
20498 | @kindex info win | |
20499 | List and give the size of all displayed windows. | |
20500 | ||
8e04817f | 20501 | @item layout next |
4644b6e3 | 20502 | @kindex layout |
8e04817f | 20503 | Display the next layout. |
2df3850c | 20504 | |
8e04817f | 20505 | @item layout prev |
8e04817f | 20506 | Display the previous layout. |
c906108c | 20507 | |
8e04817f | 20508 | @item layout src |
8e04817f | 20509 | Display the source window only. |
c906108c | 20510 | |
8e04817f | 20511 | @item layout asm |
8e04817f | 20512 | Display the assembly window only. |
c906108c | 20513 | |
8e04817f | 20514 | @item layout split |
8e04817f | 20515 | Display the source and assembly window. |
c906108c | 20516 | |
8e04817f | 20517 | @item layout regs |
8e04817f AC |
20518 | Display the register window together with the source or assembly window. |
20519 | ||
46ba6afa | 20520 | @item focus next |
8e04817f | 20521 | @kindex focus |
46ba6afa BW |
20522 | Make the next window active for scrolling. |
20523 | ||
20524 | @item focus prev | |
20525 | Make the previous window active for scrolling. | |
20526 | ||
20527 | @item focus src | |
20528 | Make the source window active for scrolling. | |
20529 | ||
20530 | @item focus asm | |
20531 | Make the assembly window active for scrolling. | |
20532 | ||
20533 | @item focus regs | |
20534 | Make the register window active for scrolling. | |
20535 | ||
20536 | @item focus cmd | |
20537 | Make the command window active for scrolling. | |
c906108c | 20538 | |
8e04817f AC |
20539 | @item refresh |
20540 | @kindex refresh | |
7f9087cb | 20541 | Refresh the screen. This is similar to typing @kbd{C-L}. |
c906108c | 20542 | |
6a1b180d SC |
20543 | @item tui reg float |
20544 | @kindex tui reg | |
20545 | Show the floating point registers in the register window. | |
20546 | ||
20547 | @item tui reg general | |
20548 | Show the general registers in the register window. | |
20549 | ||
20550 | @item tui reg next | |
20551 | Show the next register group. The list of register groups as well as | |
20552 | their order is target specific. The predefined register groups are the | |
20553 | following: @code{general}, @code{float}, @code{system}, @code{vector}, | |
20554 | @code{all}, @code{save}, @code{restore}. | |
20555 | ||
20556 | @item tui reg system | |
20557 | Show the system registers in the register window. | |
20558 | ||
8e04817f AC |
20559 | @item update |
20560 | @kindex update | |
20561 | Update the source window and the current execution point. | |
c906108c | 20562 | |
8e04817f AC |
20563 | @item winheight @var{name} +@var{count} |
20564 | @itemx winheight @var{name} -@var{count} | |
20565 | @kindex winheight | |
20566 | Change the height of the window @var{name} by @var{count} | |
20567 | lines. Positive counts increase the height, while negative counts | |
20568 | decrease it. | |
2df3850c | 20569 | |
46ba6afa BW |
20570 | @item tabset @var{nchars} |
20571 | @kindex tabset | |
c45da7e6 | 20572 | Set the width of tab stops to be @var{nchars} characters. |
c906108c SS |
20573 | @end table |
20574 | ||
8e04817f | 20575 | @node TUI Configuration |
79a6e687 | 20576 | @section TUI Configuration Variables |
8e04817f | 20577 | @cindex TUI configuration variables |
c906108c | 20578 | |
46ba6afa | 20579 | Several configuration variables control the appearance of TUI windows. |
c906108c | 20580 | |
8e04817f AC |
20581 | @table @code |
20582 | @item set tui border-kind @var{kind} | |
20583 | @kindex set tui border-kind | |
20584 | Select the border appearance for the source, assembly and register windows. | |
20585 | The possible values are the following: | |
20586 | @table @code | |
20587 | @item space | |
20588 | Use a space character to draw the border. | |
c906108c | 20589 | |
8e04817f | 20590 | @item ascii |
46ba6afa | 20591 | Use @sc{ascii} characters @samp{+}, @samp{-} and @samp{|} to draw the border. |
c906108c | 20592 | |
8e04817f AC |
20593 | @item acs |
20594 | Use the Alternate Character Set to draw the border. The border is | |
20595 | drawn using character line graphics if the terminal supports them. | |
8e04817f | 20596 | @end table |
c78b4128 | 20597 | |
8e04817f AC |
20598 | @item set tui border-mode @var{mode} |
20599 | @kindex set tui border-mode | |
46ba6afa BW |
20600 | @itemx set tui active-border-mode @var{mode} |
20601 | @kindex set tui active-border-mode | |
20602 | Select the display attributes for the borders of the inactive windows | |
20603 | or the active window. The @var{mode} can be one of the following: | |
8e04817f AC |
20604 | @table @code |
20605 | @item normal | |
20606 | Use normal attributes to display the border. | |
c906108c | 20607 | |
8e04817f AC |
20608 | @item standout |
20609 | Use standout mode. | |
c906108c | 20610 | |
8e04817f AC |
20611 | @item reverse |
20612 | Use reverse video mode. | |
c906108c | 20613 | |
8e04817f AC |
20614 | @item half |
20615 | Use half bright mode. | |
c906108c | 20616 | |
8e04817f AC |
20617 | @item half-standout |
20618 | Use half bright and standout mode. | |
c906108c | 20619 | |
8e04817f AC |
20620 | @item bold |
20621 | Use extra bright or bold mode. | |
c78b4128 | 20622 | |
8e04817f AC |
20623 | @item bold-standout |
20624 | Use extra bright or bold and standout mode. | |
8e04817f | 20625 | @end table |
8e04817f | 20626 | @end table |
c78b4128 | 20627 | |
8e04817f AC |
20628 | @node Emacs |
20629 | @chapter Using @value{GDBN} under @sc{gnu} Emacs | |
c78b4128 | 20630 | |
8e04817f AC |
20631 | @cindex Emacs |
20632 | @cindex @sc{gnu} Emacs | |
20633 | A special interface allows you to use @sc{gnu} Emacs to view (and | |
20634 | edit) the source files for the program you are debugging with | |
20635 | @value{GDBN}. | |
c906108c | 20636 | |
8e04817f AC |
20637 | To use this interface, use the command @kbd{M-x gdb} in Emacs. Give the |
20638 | executable file you want to debug as an argument. This command starts | |
20639 | @value{GDBN} as a subprocess of Emacs, with input and output through a newly | |
20640 | created Emacs buffer. | |
20641 | @c (Do not use the @code{-tui} option to run @value{GDBN} from Emacs.) | |
c906108c | 20642 | |
5e252a2e | 20643 | Running @value{GDBN} under Emacs can be just like running @value{GDBN} normally except for two |
8e04817f | 20644 | things: |
c906108c | 20645 | |
8e04817f AC |
20646 | @itemize @bullet |
20647 | @item | |
5e252a2e NR |
20648 | All ``terminal'' input and output goes through an Emacs buffer, called |
20649 | the GUD buffer. | |
c906108c | 20650 | |
8e04817f AC |
20651 | This applies both to @value{GDBN} commands and their output, and to the input |
20652 | and output done by the program you are debugging. | |
bf0184be | 20653 | |
8e04817f AC |
20654 | This is useful because it means that you can copy the text of previous |
20655 | commands and input them again; you can even use parts of the output | |
20656 | in this way. | |
bf0184be | 20657 | |
8e04817f AC |
20658 | All the facilities of Emacs' Shell mode are available for interacting |
20659 | with your program. In particular, you can send signals the usual | |
20660 | way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a | |
20661 | stop. | |
bf0184be ND |
20662 | |
20663 | @item | |
8e04817f | 20664 | @value{GDBN} displays source code through Emacs. |
bf0184be | 20665 | |
8e04817f AC |
20666 | Each time @value{GDBN} displays a stack frame, Emacs automatically finds the |
20667 | source file for that frame and puts an arrow (@samp{=>}) at the | |
20668 | left margin of the current line. Emacs uses a separate buffer for | |
20669 | source display, and splits the screen to show both your @value{GDBN} session | |
20670 | and the source. | |
bf0184be | 20671 | |
8e04817f AC |
20672 | Explicit @value{GDBN} @code{list} or search commands still produce output as |
20673 | usual, but you probably have no reason to use them from Emacs. | |
5e252a2e NR |
20674 | @end itemize |
20675 | ||
20676 | We call this @dfn{text command mode}. Emacs 22.1, and later, also uses | |
20677 | a graphical mode, enabled by default, which provides further buffers | |
20678 | that can control the execution and describe the state of your program. | |
20679 | @xref{GDB Graphical Interface,,, Emacs, The @sc{gnu} Emacs Manual}. | |
c906108c | 20680 | |
64fabec2 AC |
20681 | If you specify an absolute file name when prompted for the @kbd{M-x |
20682 | gdb} argument, then Emacs sets your current working directory to where | |
20683 | your program resides. If you only specify the file name, then Emacs | |
20684 | sets your current working directory to to the directory associated | |
20685 | with the previous buffer. In this case, @value{GDBN} may find your | |
20686 | program by searching your environment's @code{PATH} variable, but on | |
20687 | some operating systems it might not find the source. So, although the | |
20688 | @value{GDBN} input and output session proceeds normally, the auxiliary | |
20689 | buffer does not display the current source and line of execution. | |
20690 | ||
20691 | The initial working directory of @value{GDBN} is printed on the top | |
5e252a2e NR |
20692 | line of the GUD buffer and this serves as a default for the commands |
20693 | that specify files for @value{GDBN} to operate on. @xref{Files, | |
20694 | ,Commands to Specify Files}. | |
64fabec2 AC |
20695 | |
20696 | By default, @kbd{M-x gdb} calls the program called @file{gdb}. If you | |
20697 | need to call @value{GDBN} by a different name (for example, if you | |
20698 | keep several configurations around, with different names) you can | |
20699 | customize the Emacs variable @code{gud-gdb-command-name} to run the | |
20700 | one you want. | |
8e04817f | 20701 | |
5e252a2e | 20702 | In the GUD buffer, you can use these special Emacs commands in |
8e04817f | 20703 | addition to the standard Shell mode commands: |
c906108c | 20704 | |
8e04817f AC |
20705 | @table @kbd |
20706 | @item C-h m | |
5e252a2e | 20707 | Describe the features of Emacs' GUD Mode. |
c906108c | 20708 | |
64fabec2 | 20709 | @item C-c C-s |
8e04817f AC |
20710 | Execute to another source line, like the @value{GDBN} @code{step} command; also |
20711 | update the display window to show the current file and location. | |
c906108c | 20712 | |
64fabec2 | 20713 | @item C-c C-n |
8e04817f AC |
20714 | Execute to next source line in this function, skipping all function |
20715 | calls, like the @value{GDBN} @code{next} command. Then update the display window | |
20716 | to show the current file and location. | |
c906108c | 20717 | |
64fabec2 | 20718 | @item C-c C-i |
8e04817f AC |
20719 | Execute one instruction, like the @value{GDBN} @code{stepi} command; update |
20720 | display window accordingly. | |
c906108c | 20721 | |
8e04817f AC |
20722 | @item C-c C-f |
20723 | Execute until exit from the selected stack frame, like the @value{GDBN} | |
20724 | @code{finish} command. | |
c906108c | 20725 | |
64fabec2 | 20726 | @item C-c C-r |
8e04817f AC |
20727 | Continue execution of your program, like the @value{GDBN} @code{continue} |
20728 | command. | |
b433d00b | 20729 | |
64fabec2 | 20730 | @item C-c < |
8e04817f AC |
20731 | Go up the number of frames indicated by the numeric argument |
20732 | (@pxref{Arguments, , Numeric Arguments, Emacs, The @sc{gnu} Emacs Manual}), | |
20733 | like the @value{GDBN} @code{up} command. | |
b433d00b | 20734 | |
64fabec2 | 20735 | @item C-c > |
8e04817f AC |
20736 | Go down the number of frames indicated by the numeric argument, like the |
20737 | @value{GDBN} @code{down} command. | |
8e04817f | 20738 | @end table |
c906108c | 20739 | |
7f9087cb | 20740 | In any source file, the Emacs command @kbd{C-x @key{SPC}} (@code{gud-break}) |
8e04817f | 20741 | tells @value{GDBN} to set a breakpoint on the source line point is on. |
c906108c | 20742 | |
5e252a2e NR |
20743 | In text command mode, if you type @kbd{M-x speedbar}, Emacs displays a |
20744 | separate frame which shows a backtrace when the GUD buffer is current. | |
20745 | Move point to any frame in the stack and type @key{RET} to make it | |
20746 | become the current frame and display the associated source in the | |
20747 | source buffer. Alternatively, click @kbd{Mouse-2} to make the | |
20748 | selected frame become the current one. In graphical mode, the | |
20749 | speedbar displays watch expressions. | |
64fabec2 | 20750 | |
8e04817f AC |
20751 | If you accidentally delete the source-display buffer, an easy way to get |
20752 | it back is to type the command @code{f} in the @value{GDBN} buffer, to | |
20753 | request a frame display; when you run under Emacs, this recreates | |
20754 | the source buffer if necessary to show you the context of the current | |
20755 | frame. | |
c906108c | 20756 | |
8e04817f AC |
20757 | The source files displayed in Emacs are in ordinary Emacs buffers |
20758 | which are visiting the source files in the usual way. You can edit | |
20759 | the files with these buffers if you wish; but keep in mind that @value{GDBN} | |
20760 | communicates with Emacs in terms of line numbers. If you add or | |
20761 | delete lines from the text, the line numbers that @value{GDBN} knows cease | |
20762 | to correspond properly with the code. | |
b383017d | 20763 | |
5e252a2e NR |
20764 | A more detailed description of Emacs' interaction with @value{GDBN} is |
20765 | given in the Emacs manual (@pxref{Debuggers,,, Emacs, The @sc{gnu} | |
20766 | Emacs Manual}). | |
c906108c | 20767 | |
8e04817f AC |
20768 | @c The following dropped because Epoch is nonstandard. Reactivate |
20769 | @c if/when v19 does something similar. ---doc@cygnus.com 19dec1990 | |
20770 | @ignore | |
20771 | @kindex Emacs Epoch environment | |
20772 | @kindex Epoch | |
20773 | @kindex inspect | |
c906108c | 20774 | |
8e04817f AC |
20775 | Version 18 of @sc{gnu} Emacs has a built-in window system |
20776 | called the @code{epoch} | |
20777 | environment. Users of this environment can use a new command, | |
20778 | @code{inspect} which performs identically to @code{print} except that | |
20779 | each value is printed in its own window. | |
20780 | @end ignore | |
c906108c | 20781 | |
922fbb7b AC |
20782 | |
20783 | @node GDB/MI | |
20784 | @chapter The @sc{gdb/mi} Interface | |
20785 | ||
20786 | @unnumberedsec Function and Purpose | |
20787 | ||
20788 | @cindex @sc{gdb/mi}, its purpose | |
6b5e8c01 NR |
20789 | @sc{gdb/mi} is a line based machine oriented text interface to |
20790 | @value{GDBN} and is activated by specifying using the | |
20791 | @option{--interpreter} command line option (@pxref{Mode Options}). It | |
20792 | is specifically intended to support the development of systems which | |
20793 | use the debugger as just one small component of a larger system. | |
922fbb7b AC |
20794 | |
20795 | This chapter is a specification of the @sc{gdb/mi} interface. It is written | |
20796 | in the form of a reference manual. | |
20797 | ||
20798 | Note that @sc{gdb/mi} is still under construction, so some of the | |
af6eff6f NR |
20799 | features described below are incomplete and subject to change |
20800 | (@pxref{GDB/MI Development and Front Ends, , @sc{gdb/mi} Development and Front Ends}). | |
922fbb7b AC |
20801 | |
20802 | @unnumberedsec Notation and Terminology | |
20803 | ||
20804 | @cindex notational conventions, for @sc{gdb/mi} | |
20805 | This chapter uses the following notation: | |
20806 | ||
20807 | @itemize @bullet | |
20808 | @item | |
20809 | @code{|} separates two alternatives. | |
20810 | ||
20811 | @item | |
20812 | @code{[ @var{something} ]} indicates that @var{something} is optional: | |
20813 | it may or may not be given. | |
20814 | ||
20815 | @item | |
20816 | @code{( @var{group} )*} means that @var{group} inside the parentheses | |
20817 | may repeat zero or more times. | |
20818 | ||
20819 | @item | |
20820 | @code{( @var{group} )+} means that @var{group} inside the parentheses | |
20821 | may repeat one or more times. | |
20822 | ||
20823 | @item | |
20824 | @code{"@var{string}"} means a literal @var{string}. | |
20825 | @end itemize | |
20826 | ||
20827 | @ignore | |
20828 | @heading Dependencies | |
20829 | @end ignore | |
20830 | ||
922fbb7b | 20831 | @menu |
c3b108f7 | 20832 | * GDB/MI General Design:: |
922fbb7b AC |
20833 | * GDB/MI Command Syntax:: |
20834 | * GDB/MI Compatibility with CLI:: | |
af6eff6f | 20835 | * GDB/MI Development and Front Ends:: |
922fbb7b | 20836 | * GDB/MI Output Records:: |
ef21caaf | 20837 | * GDB/MI Simple Examples:: |
922fbb7b | 20838 | * GDB/MI Command Description Format:: |
ef21caaf | 20839 | * GDB/MI Breakpoint Commands:: |
a2c02241 NR |
20840 | * GDB/MI Program Context:: |
20841 | * GDB/MI Thread Commands:: | |
20842 | * GDB/MI Program Execution:: | |
20843 | * GDB/MI Stack Manipulation:: | |
20844 | * GDB/MI Variable Objects:: | |
922fbb7b | 20845 | * GDB/MI Data Manipulation:: |
a2c02241 NR |
20846 | * GDB/MI Tracepoint Commands:: |
20847 | * GDB/MI Symbol Query:: | |
351ff01a | 20848 | * GDB/MI File Commands:: |
922fbb7b AC |
20849 | @ignore |
20850 | * GDB/MI Kod Commands:: | |
20851 | * GDB/MI Memory Overlay Commands:: | |
20852 | * GDB/MI Signal Handling Commands:: | |
20853 | @end ignore | |
922fbb7b | 20854 | * GDB/MI Target Manipulation:: |
a6b151f1 | 20855 | * GDB/MI File Transfer Commands:: |
ef21caaf | 20856 | * GDB/MI Miscellaneous Commands:: |
922fbb7b AC |
20857 | @end menu |
20858 | ||
c3b108f7 VP |
20859 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
20860 | @node GDB/MI General Design | |
20861 | @section @sc{gdb/mi} General Design | |
20862 | @cindex GDB/MI General Design | |
20863 | ||
20864 | Interaction of a @sc{GDB/MI} frontend with @value{GDBN} involves three | |
20865 | parts---commands sent to @value{GDBN}, responses to those commands | |
20866 | and notifications. Each command results in exactly one response, | |
20867 | indicating either successful completion of the command, or an error. | |
20868 | For the commands that do not resume the target, the response contains the | |
20869 | requested information. For the commands that resume the target, the | |
20870 | response only indicates whether the target was successfully resumed. | |
20871 | Notifications is the mechanism for reporting changes in the state of the | |
20872 | target, or in @value{GDBN} state, that cannot conveniently be associated with | |
20873 | a command and reported as part of that command response. | |
20874 | ||
20875 | The important examples of notifications are: | |
20876 | @itemize @bullet | |
20877 | ||
20878 | @item | |
20879 | Exec notifications. These are used to report changes in | |
20880 | target state---when a target is resumed, or stopped. It would not | |
20881 | be feasible to include this information in response of resuming | |
20882 | commands, because one resume commands can result in multiple events in | |
20883 | different threads. Also, quite some time may pass before any event | |
20884 | happens in the target, while a frontend needs to know whether the resuming | |
20885 | command itself was successfully executed. | |
20886 | ||
20887 | @item | |
20888 | Console output, and status notifications. Console output | |
20889 | notifications are used to report output of CLI commands, as well as | |
20890 | diagnostics for other commands. Status notifications are used to | |
20891 | report the progress of a long-running operation. Naturally, including | |
20892 | this information in command response would mean no output is produced | |
20893 | until the command is finished, which is undesirable. | |
20894 | ||
20895 | @item | |
20896 | General notifications. Commands may have various side effects on | |
20897 | the @value{GDBN} or target state beyond their official purpose. For example, | |
20898 | a command may change the selected thread. Although such changes can | |
20899 | be included in command response, using notification allows for more | |
20900 | orthogonal frontend design. | |
20901 | ||
20902 | @end itemize | |
20903 | ||
20904 | There's no guarantee that whenever an MI command reports an error, | |
20905 | @value{GDBN} or the target are in any specific state, and especially, | |
20906 | the state is not reverted to the state before the MI command was | |
20907 | processed. Therefore, whenever an MI command results in an error, | |
20908 | we recommend that the frontend refreshes all the information shown in | |
20909 | the user interface. | |
20910 | ||
508094de NR |
20911 | |
20912 | @menu | |
20913 | * Context management:: | |
20914 | * Asynchronous and non-stop modes:: | |
20915 | * Thread groups:: | |
20916 | @end menu | |
20917 | ||
20918 | @node Context management | |
c3b108f7 VP |
20919 | @subsection Context management |
20920 | ||
20921 | In most cases when @value{GDBN} accesses the target, this access is | |
20922 | done in context of a specific thread and frame (@pxref{Frames}). | |
20923 | Often, even when accessing global data, the target requires that a thread | |
20924 | be specified. The CLI interface maintains the selected thread and frame, | |
20925 | and supplies them to target on each command. This is convenient, | |
20926 | because a command line user would not want to specify that information | |
20927 | explicitly on each command, and because user interacts with | |
20928 | @value{GDBN} via a single terminal, so no confusion is possible as | |
20929 | to what thread and frame are the current ones. | |
20930 | ||
20931 | In the case of MI, the concept of selected thread and frame is less | |
20932 | useful. First, a frontend can easily remember this information | |
20933 | itself. Second, a graphical frontend can have more than one window, | |
20934 | each one used for debugging a different thread, and the frontend might | |
20935 | want to access additional threads for internal purposes. This | |
20936 | increases the risk that by relying on implicitly selected thread, the | |
20937 | frontend may be operating on a wrong one. Therefore, each MI command | |
20938 | should explicitly specify which thread and frame to operate on. To | |
20939 | make it possible, each MI command accepts the @samp{--thread} and | |
20940 | @samp{--frame} options, the value to each is @value{GDBN} identifier | |
20941 | for thread and frame to operate on. | |
20942 | ||
20943 | Usually, each top-level window in a frontend allows the user to select | |
20944 | a thread and a frame, and remembers the user selection for further | |
20945 | operations. However, in some cases @value{GDBN} may suggest that the | |
20946 | current thread be changed. For example, when stopping on a breakpoint | |
20947 | it is reasonable to switch to the thread where breakpoint is hit. For | |
20948 | another example, if the user issues the CLI @samp{thread} command via | |
20949 | the frontend, it is desirable to change the frontend's selected thread to the | |
20950 | one specified by user. @value{GDBN} communicates the suggestion to | |
20951 | change current thread using the @samp{=thread-selected} notification. | |
20952 | No such notification is available for the selected frame at the moment. | |
20953 | ||
20954 | Note that historically, MI shares the selected thread with CLI, so | |
20955 | frontends used the @code{-thread-select} to execute commands in the | |
20956 | right context. However, getting this to work right is cumbersome. The | |
20957 | simplest way is for frontend to emit @code{-thread-select} command | |
20958 | before every command. This doubles the number of commands that need | |
20959 | to be sent. The alternative approach is to suppress @code{-thread-select} | |
20960 | if the selected thread in @value{GDBN} is supposed to be identical to the | |
20961 | thread the frontend wants to operate on. However, getting this | |
20962 | optimization right can be tricky. In particular, if the frontend | |
20963 | sends several commands to @value{GDBN}, and one of the commands changes the | |
20964 | selected thread, then the behaviour of subsequent commands will | |
20965 | change. So, a frontend should either wait for response from such | |
20966 | problematic commands, or explicitly add @code{-thread-select} for | |
20967 | all subsequent commands. No frontend is known to do this exactly | |
20968 | right, so it is suggested to just always pass the @samp{--thread} and | |
20969 | @samp{--frame} options. | |
20970 | ||
508094de | 20971 | @node Asynchronous and non-stop modes |
c3b108f7 VP |
20972 | @subsection Asynchronous command execution and non-stop mode |
20973 | ||
20974 | On some targets, @value{GDBN} is capable of processing MI commands | |
20975 | even while the target is running. This is called @dfn{asynchronous | |
20976 | command execution} (@pxref{Background Execution}). The frontend may | |
20977 | specify a preferrence for asynchronous execution using the | |
20978 | @code{-gdb-set target-async 1} command, which should be emitted before | |
20979 | either running the executable or attaching to the target. After the | |
20980 | frontend has started the executable or attached to the target, it can | |
20981 | find if asynchronous execution is enabled using the | |
20982 | @code{-list-target-features} command. | |
20983 | ||
20984 | Even if @value{GDBN} can accept a command while target is running, | |
20985 | many commands that access the target do not work when the target is | |
20986 | running. Therefore, asynchronous command execution is most useful | |
20987 | when combined with non-stop mode (@pxref{Non-Stop Mode}). Then, | |
20988 | it is possible to examine the state of one thread, while other threads | |
20989 | are running. | |
20990 | ||
20991 | When a given thread is running, MI commands that try to access the | |
20992 | target in the context of that thread may not work, or may work only on | |
20993 | some targets. In particular, commands that try to operate on thread's | |
20994 | stack will not work, on any target. Commands that read memory, or | |
20995 | modify breakpoints, may work or not work, depending on the target. Note | |
20996 | that even commands that operate on global state, such as @code{print}, | |
20997 | @code{set}, and breakpoint commands, still access the target in the | |
20998 | context of a specific thread, so frontend should try to find a | |
20999 | stopped thread and perform the operation on that thread (using the | |
21000 | @samp{--thread} option). | |
21001 | ||
21002 | Which commands will work in the context of a running thread is | |
21003 | highly target dependent. However, the two commands | |
21004 | @code{-exec-interrupt}, to stop a thread, and @code{-thread-info}, | |
21005 | to find the state of a thread, will always work. | |
21006 | ||
508094de | 21007 | @node Thread groups |
c3b108f7 VP |
21008 | @subsection Thread groups |
21009 | @value{GDBN} may be used to debug several processes at the same time. | |
21010 | On some platfroms, @value{GDBN} may support debugging of several | |
21011 | hardware systems, each one having several cores with several different | |
21012 | processes running on each core. This section describes the MI | |
21013 | mechanism to support such debugging scenarios. | |
21014 | ||
21015 | The key observation is that regardless of the structure of the | |
21016 | target, MI can have a global list of threads, because most commands that | |
21017 | accept the @samp{--thread} option do not need to know what process that | |
21018 | thread belongs to. Therefore, it is not necessary to introduce | |
21019 | neither additional @samp{--process} option, nor an notion of the | |
21020 | current process in the MI interface. The only strictly new feature | |
21021 | that is required is the ability to find how the threads are grouped | |
21022 | into processes. | |
21023 | ||
21024 | To allow the user to discover such grouping, and to support arbitrary | |
21025 | hierarchy of machines/cores/processes, MI introduces the concept of a | |
21026 | @dfn{thread group}. Thread group is a collection of threads and other | |
21027 | thread groups. A thread group always has a string identifier, a type, | |
21028 | and may have additional attributes specific to the type. A new | |
21029 | command, @code{-list-thread-groups}, returns the list of top-level | |
21030 | thread groups, which correspond to processes that @value{GDBN} is | |
21031 | debugging at the moment. By passing an identifier of a thread group | |
21032 | to the @code{-list-thread-groups} command, it is possible to obtain | |
21033 | the members of specific thread group. | |
21034 | ||
21035 | To allow the user to easily discover processes, and other objects, he | |
21036 | wishes to debug, a concept of @dfn{available thread group} is | |
21037 | introduced. Available thread group is an thread group that | |
21038 | @value{GDBN} is not debugging, but that can be attached to, using the | |
21039 | @code{-target-attach} command. The list of available top-level thread | |
21040 | groups can be obtained using @samp{-list-thread-groups --available}. | |
21041 | In general, the content of a thread group may be only retrieved only | |
21042 | after attaching to that thread group. | |
21043 | ||
922fbb7b AC |
21044 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21045 | @node GDB/MI Command Syntax | |
21046 | @section @sc{gdb/mi} Command Syntax | |
21047 | ||
21048 | @menu | |
21049 | * GDB/MI Input Syntax:: | |
21050 | * GDB/MI Output Syntax:: | |
922fbb7b AC |
21051 | @end menu |
21052 | ||
21053 | @node GDB/MI Input Syntax | |
21054 | @subsection @sc{gdb/mi} Input Syntax | |
21055 | ||
21056 | @cindex input syntax for @sc{gdb/mi} | |
21057 | @cindex @sc{gdb/mi}, input syntax | |
21058 | @table @code | |
21059 | @item @var{command} @expansion{} | |
21060 | @code{@var{cli-command} | @var{mi-command}} | |
21061 | ||
21062 | @item @var{cli-command} @expansion{} | |
21063 | @code{[ @var{token} ] @var{cli-command} @var{nl}}, where | |
21064 | @var{cli-command} is any existing @value{GDBN} CLI command. | |
21065 | ||
21066 | @item @var{mi-command} @expansion{} | |
21067 | @code{[ @var{token} ] "-" @var{operation} ( " " @var{option} )* | |
21068 | @code{[} " --" @code{]} ( " " @var{parameter} )* @var{nl}} | |
21069 | ||
21070 | @item @var{token} @expansion{} | |
21071 | "any sequence of digits" | |
21072 | ||
21073 | @item @var{option} @expansion{} | |
21074 | @code{"-" @var{parameter} [ " " @var{parameter} ]} | |
21075 | ||
21076 | @item @var{parameter} @expansion{} | |
21077 | @code{@var{non-blank-sequence} | @var{c-string}} | |
21078 | ||
21079 | @item @var{operation} @expansion{} | |
21080 | @emph{any of the operations described in this chapter} | |
21081 | ||
21082 | @item @var{non-blank-sequence} @expansion{} | |
21083 | @emph{anything, provided it doesn't contain special characters such as | |
21084 | "-", @var{nl}, """ and of course " "} | |
21085 | ||
21086 | @item @var{c-string} @expansion{} | |
21087 | @code{""" @var{seven-bit-iso-c-string-content} """} | |
21088 | ||
21089 | @item @var{nl} @expansion{} | |
21090 | @code{CR | CR-LF} | |
21091 | @end table | |
21092 | ||
21093 | @noindent | |
21094 | Notes: | |
21095 | ||
21096 | @itemize @bullet | |
21097 | @item | |
21098 | The CLI commands are still handled by the @sc{mi} interpreter; their | |
21099 | output is described below. | |
21100 | ||
21101 | @item | |
21102 | The @code{@var{token}}, when present, is passed back when the command | |
21103 | finishes. | |
21104 | ||
21105 | @item | |
21106 | Some @sc{mi} commands accept optional arguments as part of the parameter | |
21107 | list. Each option is identified by a leading @samp{-} (dash) and may be | |
21108 | followed by an optional argument parameter. Options occur first in the | |
21109 | parameter list and can be delimited from normal parameters using | |
21110 | @samp{--} (this is useful when some parameters begin with a dash). | |
21111 | @end itemize | |
21112 | ||
21113 | Pragmatics: | |
21114 | ||
21115 | @itemize @bullet | |
21116 | @item | |
21117 | We want easy access to the existing CLI syntax (for debugging). | |
21118 | ||
21119 | @item | |
21120 | We want it to be easy to spot a @sc{mi} operation. | |
21121 | @end itemize | |
21122 | ||
21123 | @node GDB/MI Output Syntax | |
21124 | @subsection @sc{gdb/mi} Output Syntax | |
21125 | ||
21126 | @cindex output syntax of @sc{gdb/mi} | |
21127 | @cindex @sc{gdb/mi}, output syntax | |
21128 | The output from @sc{gdb/mi} consists of zero or more out-of-band records | |
21129 | followed, optionally, by a single result record. This result record | |
21130 | is for the most recent command. The sequence of output records is | |
594fe323 | 21131 | terminated by @samp{(gdb)}. |
922fbb7b AC |
21132 | |
21133 | If an input command was prefixed with a @code{@var{token}} then the | |
21134 | corresponding output for that command will also be prefixed by that same | |
21135 | @var{token}. | |
21136 | ||
21137 | @table @code | |
21138 | @item @var{output} @expansion{} | |
594fe323 | 21139 | @code{( @var{out-of-band-record} )* [ @var{result-record} ] "(gdb)" @var{nl}} |
922fbb7b AC |
21140 | |
21141 | @item @var{result-record} @expansion{} | |
21142 | @code{ [ @var{token} ] "^" @var{result-class} ( "," @var{result} )* @var{nl}} | |
21143 | ||
21144 | @item @var{out-of-band-record} @expansion{} | |
21145 | @code{@var{async-record} | @var{stream-record}} | |
21146 | ||
21147 | @item @var{async-record} @expansion{} | |
21148 | @code{@var{exec-async-output} | @var{status-async-output} | @var{notify-async-output}} | |
21149 | ||
21150 | @item @var{exec-async-output} @expansion{} | |
21151 | @code{[ @var{token} ] "*" @var{async-output}} | |
21152 | ||
21153 | @item @var{status-async-output} @expansion{} | |
21154 | @code{[ @var{token} ] "+" @var{async-output}} | |
21155 | ||
21156 | @item @var{notify-async-output} @expansion{} | |
21157 | @code{[ @var{token} ] "=" @var{async-output}} | |
21158 | ||
21159 | @item @var{async-output} @expansion{} | |
21160 | @code{@var{async-class} ( "," @var{result} )* @var{nl}} | |
21161 | ||
21162 | @item @var{result-class} @expansion{} | |
21163 | @code{"done" | "running" | "connected" | "error" | "exit"} | |
21164 | ||
21165 | @item @var{async-class} @expansion{} | |
21166 | @code{"stopped" | @var{others}} (where @var{others} will be added | |
21167 | depending on the needs---this is still in development). | |
21168 | ||
21169 | @item @var{result} @expansion{} | |
21170 | @code{ @var{variable} "=" @var{value}} | |
21171 | ||
21172 | @item @var{variable} @expansion{} | |
21173 | @code{ @var{string} } | |
21174 | ||
21175 | @item @var{value} @expansion{} | |
21176 | @code{ @var{const} | @var{tuple} | @var{list} } | |
21177 | ||
21178 | @item @var{const} @expansion{} | |
21179 | @code{@var{c-string}} | |
21180 | ||
21181 | @item @var{tuple} @expansion{} | |
21182 | @code{ "@{@}" | "@{" @var{result} ( "," @var{result} )* "@}" } | |
21183 | ||
21184 | @item @var{list} @expansion{} | |
21185 | @code{ "[]" | "[" @var{value} ( "," @var{value} )* "]" | "[" | |
21186 | @var{result} ( "," @var{result} )* "]" } | |
21187 | ||
21188 | @item @var{stream-record} @expansion{} | |
21189 | @code{@var{console-stream-output} | @var{target-stream-output} | @var{log-stream-output}} | |
21190 | ||
21191 | @item @var{console-stream-output} @expansion{} | |
21192 | @code{"~" @var{c-string}} | |
21193 | ||
21194 | @item @var{target-stream-output} @expansion{} | |
21195 | @code{"@@" @var{c-string}} | |
21196 | ||
21197 | @item @var{log-stream-output} @expansion{} | |
21198 | @code{"&" @var{c-string}} | |
21199 | ||
21200 | @item @var{nl} @expansion{} | |
21201 | @code{CR | CR-LF} | |
21202 | ||
21203 | @item @var{token} @expansion{} | |
21204 | @emph{any sequence of digits}. | |
21205 | @end table | |
21206 | ||
21207 | @noindent | |
21208 | Notes: | |
21209 | ||
21210 | @itemize @bullet | |
21211 | @item | |
21212 | All output sequences end in a single line containing a period. | |
21213 | ||
21214 | @item | |
721c02de VP |
21215 | The @code{@var{token}} is from the corresponding request. Note that |
21216 | for all async output, while the token is allowed by the grammar and | |
21217 | may be output by future versions of @value{GDBN} for select async | |
21218 | output messages, it is generally omitted. Frontends should treat | |
21219 | all async output as reporting general changes in the state of the | |
21220 | target and there should be no need to associate async output to any | |
21221 | prior command. | |
922fbb7b AC |
21222 | |
21223 | @item | |
21224 | @cindex status output in @sc{gdb/mi} | |
21225 | @var{status-async-output} contains on-going status information about the | |
21226 | progress of a slow operation. It can be discarded. All status output is | |
21227 | prefixed by @samp{+}. | |
21228 | ||
21229 | @item | |
21230 | @cindex async output in @sc{gdb/mi} | |
21231 | @var{exec-async-output} contains asynchronous state change on the target | |
21232 | (stopped, started, disappeared). All async output is prefixed by | |
21233 | @samp{*}. | |
21234 | ||
21235 | @item | |
21236 | @cindex notify output in @sc{gdb/mi} | |
21237 | @var{notify-async-output} contains supplementary information that the | |
21238 | client should handle (e.g., a new breakpoint information). All notify | |
21239 | output is prefixed by @samp{=}. | |
21240 | ||
21241 | @item | |
21242 | @cindex console output in @sc{gdb/mi} | |
21243 | @var{console-stream-output} is output that should be displayed as is in the | |
21244 | console. It is the textual response to a CLI command. All the console | |
21245 | output is prefixed by @samp{~}. | |
21246 | ||
21247 | @item | |
21248 | @cindex target output in @sc{gdb/mi} | |
21249 | @var{target-stream-output} is the output produced by the target program. | |
21250 | All the target output is prefixed by @samp{@@}. | |
21251 | ||
21252 | @item | |
21253 | @cindex log output in @sc{gdb/mi} | |
21254 | @var{log-stream-output} is output text coming from @value{GDBN}'s internals, for | |
21255 | instance messages that should be displayed as part of an error log. All | |
21256 | the log output is prefixed by @samp{&}. | |
21257 | ||
21258 | @item | |
21259 | @cindex list output in @sc{gdb/mi} | |
21260 | New @sc{gdb/mi} commands should only output @var{lists} containing | |
21261 | @var{values}. | |
21262 | ||
21263 | ||
21264 | @end itemize | |
21265 | ||
21266 | @xref{GDB/MI Stream Records, , @sc{gdb/mi} Stream Records}, for more | |
21267 | details about the various output records. | |
21268 | ||
922fbb7b AC |
21269 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21270 | @node GDB/MI Compatibility with CLI | |
21271 | @section @sc{gdb/mi} Compatibility with CLI | |
21272 | ||
21273 | @cindex compatibility, @sc{gdb/mi} and CLI | |
21274 | @cindex @sc{gdb/mi}, compatibility with CLI | |
922fbb7b | 21275 | |
a2c02241 NR |
21276 | For the developers convenience CLI commands can be entered directly, |
21277 | but there may be some unexpected behaviour. For example, commands | |
21278 | that query the user will behave as if the user replied yes, breakpoint | |
21279 | command lists are not executed and some CLI commands, such as | |
21280 | @code{if}, @code{when} and @code{define}, prompt for further input with | |
21281 | @samp{>}, which is not valid MI output. | |
ef21caaf NR |
21282 | |
21283 | This feature may be removed at some stage in the future and it is | |
a2c02241 NR |
21284 | recommended that front ends use the @code{-interpreter-exec} command |
21285 | (@pxref{-interpreter-exec}). | |
922fbb7b | 21286 | |
af6eff6f NR |
21287 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21288 | @node GDB/MI Development and Front Ends | |
21289 | @section @sc{gdb/mi} Development and Front Ends | |
21290 | @cindex @sc{gdb/mi} development | |
21291 | ||
21292 | The application which takes the MI output and presents the state of the | |
21293 | program being debugged to the user is called a @dfn{front end}. | |
21294 | ||
21295 | Although @sc{gdb/mi} is still incomplete, it is currently being used | |
21296 | by a variety of front ends to @value{GDBN}. This makes it difficult | |
21297 | to introduce new functionality without breaking existing usage. This | |
21298 | section tries to minimize the problems by describing how the protocol | |
21299 | might change. | |
21300 | ||
21301 | Some changes in MI need not break a carefully designed front end, and | |
21302 | for these the MI version will remain unchanged. The following is a | |
21303 | list of changes that may occur within one level, so front ends should | |
21304 | parse MI output in a way that can handle them: | |
21305 | ||
21306 | @itemize @bullet | |
21307 | @item | |
21308 | New MI commands may be added. | |
21309 | ||
21310 | @item | |
21311 | New fields may be added to the output of any MI command. | |
21312 | ||
36ece8b3 NR |
21313 | @item |
21314 | The range of values for fields with specified values, e.g., | |
9f708cb2 | 21315 | @code{in_scope} (@pxref{-var-update}) may be extended. |
36ece8b3 | 21316 | |
af6eff6f NR |
21317 | @c The format of field's content e.g type prefix, may change so parse it |
21318 | @c at your own risk. Yes, in general? | |
21319 | ||
21320 | @c The order of fields may change? Shouldn't really matter but it might | |
21321 | @c resolve inconsistencies. | |
21322 | @end itemize | |
21323 | ||
21324 | If the changes are likely to break front ends, the MI version level | |
21325 | will be increased by one. This will allow the front end to parse the | |
21326 | output according to the MI version. Apart from mi0, new versions of | |
21327 | @value{GDBN} will not support old versions of MI and it will be the | |
21328 | responsibility of the front end to work with the new one. | |
21329 | ||
21330 | @c Starting with mi3, add a new command -mi-version that prints the MI | |
21331 | @c version? | |
21332 | ||
21333 | The best way to avoid unexpected changes in MI that might break your front | |
21334 | end is to make your project known to @value{GDBN} developers and | |
7a9a6b69 | 21335 | follow development on @email{gdb@@sourceware.org} and |
fa0f268d | 21336 | @email{gdb-patches@@sourceware.org}. |
af6eff6f NR |
21337 | @cindex mailing lists |
21338 | ||
922fbb7b AC |
21339 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21340 | @node GDB/MI Output Records | |
21341 | @section @sc{gdb/mi} Output Records | |
21342 | ||
21343 | @menu | |
21344 | * GDB/MI Result Records:: | |
21345 | * GDB/MI Stream Records:: | |
82f68b1c | 21346 | * GDB/MI Async Records:: |
c3b108f7 | 21347 | * GDB/MI Frame Information:: |
922fbb7b AC |
21348 | @end menu |
21349 | ||
21350 | @node GDB/MI Result Records | |
21351 | @subsection @sc{gdb/mi} Result Records | |
21352 | ||
21353 | @cindex result records in @sc{gdb/mi} | |
21354 | @cindex @sc{gdb/mi}, result records | |
21355 | In addition to a number of out-of-band notifications, the response to a | |
21356 | @sc{gdb/mi} command includes one of the following result indications: | |
21357 | ||
21358 | @table @code | |
21359 | @findex ^done | |
21360 | @item "^done" [ "," @var{results} ] | |
21361 | The synchronous operation was successful, @code{@var{results}} are the return | |
21362 | values. | |
21363 | ||
21364 | @item "^running" | |
21365 | @findex ^running | |
21366 | @c Is this one correct? Should it be an out-of-band notification? | |
21367 | The asynchronous operation was successfully started. The target is | |
21368 | running. | |
21369 | ||
ef21caaf NR |
21370 | @item "^connected" |
21371 | @findex ^connected | |
3f94c067 | 21372 | @value{GDBN} has connected to a remote target. |
ef21caaf | 21373 | |
922fbb7b AC |
21374 | @item "^error" "," @var{c-string} |
21375 | @findex ^error | |
21376 | The operation failed. The @code{@var{c-string}} contains the corresponding | |
21377 | error message. | |
ef21caaf NR |
21378 | |
21379 | @item "^exit" | |
21380 | @findex ^exit | |
3f94c067 | 21381 | @value{GDBN} has terminated. |
ef21caaf | 21382 | |
922fbb7b AC |
21383 | @end table |
21384 | ||
21385 | @node GDB/MI Stream Records | |
21386 | @subsection @sc{gdb/mi} Stream Records | |
21387 | ||
21388 | @cindex @sc{gdb/mi}, stream records | |
21389 | @cindex stream records in @sc{gdb/mi} | |
21390 | @value{GDBN} internally maintains a number of output streams: the console, the | |
21391 | target, and the log. The output intended for each of these streams is | |
21392 | funneled through the @sc{gdb/mi} interface using @dfn{stream records}. | |
21393 | ||
21394 | Each stream record begins with a unique @dfn{prefix character} which | |
21395 | identifies its stream (@pxref{GDB/MI Output Syntax, , @sc{gdb/mi} Output | |
21396 | Syntax}). In addition to the prefix, each stream record contains a | |
21397 | @code{@var{string-output}}. This is either raw text (with an implicit new | |
21398 | line) or a quoted C string (which does not contain an implicit newline). | |
21399 | ||
21400 | @table @code | |
21401 | @item "~" @var{string-output} | |
21402 | The console output stream contains text that should be displayed in the | |
21403 | CLI console window. It contains the textual responses to CLI commands. | |
21404 | ||
21405 | @item "@@" @var{string-output} | |
21406 | The target output stream contains any textual output from the running | |
ef21caaf NR |
21407 | target. This is only present when GDB's event loop is truly |
21408 | asynchronous, which is currently only the case for remote targets. | |
922fbb7b AC |
21409 | |
21410 | @item "&" @var{string-output} | |
21411 | The log stream contains debugging messages being produced by @value{GDBN}'s | |
21412 | internals. | |
21413 | @end table | |
21414 | ||
82f68b1c VP |
21415 | @node GDB/MI Async Records |
21416 | @subsection @sc{gdb/mi} Async Records | |
922fbb7b | 21417 | |
82f68b1c VP |
21418 | @cindex async records in @sc{gdb/mi} |
21419 | @cindex @sc{gdb/mi}, async records | |
21420 | @dfn{Async} records are used to notify the @sc{gdb/mi} client of | |
922fbb7b | 21421 | additional changes that have occurred. Those changes can either be a |
82f68b1c | 21422 | consequence of @sc{gdb/mi} commands (e.g., a breakpoint modified) or a result of |
922fbb7b AC |
21423 | target activity (e.g., target stopped). |
21424 | ||
8eb41542 | 21425 | The following is the list of possible async records: |
922fbb7b AC |
21426 | |
21427 | @table @code | |
034dad6f | 21428 | |
e1ac3328 VP |
21429 | @item *running,thread-id="@var{thread}" |
21430 | The target is now running. The @var{thread} field tells which | |
21431 | specific thread is now running, and can be @samp{all} if all threads | |
21432 | are running. The frontend should assume that no interaction with a | |
21433 | running thread is possible after this notification is produced. | |
21434 | The frontend should not assume that this notification is output | |
21435 | only once for any command. @value{GDBN} may emit this notification | |
21436 | several times, either for different threads, because it cannot resume | |
21437 | all threads together, or even for a single thread, if the thread must | |
21438 | be stepped though some code before letting it run freely. | |
21439 | ||
c3b108f7 | 21440 | @item *stopped,reason="@var{reason}",thread-id="@var{id}",stopped-threads="@var{stopped}" |
82f68b1c VP |
21441 | The target has stopped. The @var{reason} field can have one of the |
21442 | following values: | |
034dad6f BR |
21443 | |
21444 | @table @code | |
21445 | @item breakpoint-hit | |
21446 | A breakpoint was reached. | |
21447 | @item watchpoint-trigger | |
21448 | A watchpoint was triggered. | |
21449 | @item read-watchpoint-trigger | |
21450 | A read watchpoint was triggered. | |
21451 | @item access-watchpoint-trigger | |
21452 | An access watchpoint was triggered. | |
21453 | @item function-finished | |
21454 | An -exec-finish or similar CLI command was accomplished. | |
21455 | @item location-reached | |
21456 | An -exec-until or similar CLI command was accomplished. | |
21457 | @item watchpoint-scope | |
21458 | A watchpoint has gone out of scope. | |
21459 | @item end-stepping-range | |
21460 | An -exec-next, -exec-next-instruction, -exec-step, -exec-step-instruction or | |
21461 | similar CLI command was accomplished. | |
21462 | @item exited-signalled | |
21463 | The inferior exited because of a signal. | |
21464 | @item exited | |
21465 | The inferior exited. | |
21466 | @item exited-normally | |
21467 | The inferior exited normally. | |
21468 | @item signal-received | |
21469 | A signal was received by the inferior. | |
922fbb7b AC |
21470 | @end table |
21471 | ||
c3b108f7 VP |
21472 | The @var{id} field identifies the thread that directly caused the stop |
21473 | -- for example by hitting a breakpoint. Depending on whether all-stop | |
21474 | mode is in effect (@pxref{All-Stop Mode}), @value{GDBN} may either | |
21475 | stop all threads, or only the thread that directly triggered the stop. | |
21476 | If all threads are stopped, the @var{stopped} field will have the | |
21477 | value of @code{"all"}. Otherwise, the value of the @var{stopped} | |
21478 | field will be a list of thread identifiers. Presently, this list will | |
21479 | always include a single thread, but frontend should be prepared to see | |
21480 | several threads in the list. | |
21481 | ||
21482 | @item =thread-group-created,id="@var{id}" | |
21483 | @itemx =thread-group-exited,id="@var{id}" | |
21484 | A thread thread group either was attached to, or has exited/detached | |
21485 | from. The @var{id} field contains the @value{GDBN} identifier of the | |
21486 | thread group. | |
21487 | ||
21488 | @item =thread-created,id="@var{id}",group-id="@var{gid}" | |
21489 | @itemx =thread-exited,id="@var{id}",group-id="@var{gid}" | |
82f68b1c | 21490 | A thread either was created, or has exited. The @var{id} field |
c3b108f7 VP |
21491 | contains the @value{GDBN} identifier of the thread. The @var{gid} |
21492 | field identifies the thread group this thread belongs to. | |
66bb093b VP |
21493 | |
21494 | @item =thread-selected,id="@var{id}" | |
21495 | Informs that the selected thread was changed as result of the last | |
21496 | command. This notification is not emitted as result of @code{-thread-select} | |
21497 | command but is emitted whenever an MI command that is not documented | |
21498 | to change the selected thread actually changes it. In particular, | |
21499 | invoking, directly or indirectly (via user-defined command), the CLI | |
21500 | @code{thread} command, will generate this notification. | |
21501 | ||
21502 | We suggest that in response to this notification, front ends | |
21503 | highlight the selected thread and cause subsequent commands to apply to | |
21504 | that thread. | |
21505 | ||
c86cf029 VP |
21506 | @item =library-loaded,... |
21507 | Reports that a new library file was loaded by the program. This | |
21508 | notification has 4 fields---@var{id}, @var{target-name}, | |
134eb42c | 21509 | @var{host-name}, and @var{symbols-loaded}. The @var{id} field is an |
c86cf029 VP |
21510 | opaque identifier of the library. For remote debugging case, |
21511 | @var{target-name} and @var{host-name} fields give the name of the | |
134eb42c VP |
21512 | library file on the target, and on the host respectively. For native |
21513 | debugging, both those fields have the same value. The | |
c86cf029 VP |
21514 | @var{symbols-loaded} field reports if the debug symbols for this |
21515 | library are loaded. | |
21516 | ||
21517 | @item =library-unloaded,... | |
134eb42c | 21518 | Reports that a library was unloaded by the program. This notification |
c86cf029 VP |
21519 | has 3 fields---@var{id}, @var{target-name} and @var{host-name} with |
21520 | the same meaning as for the @code{=library-loaded} notification | |
21521 | ||
82f68b1c VP |
21522 | @end table |
21523 | ||
c3b108f7 VP |
21524 | @node GDB/MI Frame Information |
21525 | @subsection @sc{gdb/mi} Frame Information | |
21526 | ||
21527 | Response from many MI commands includes an information about stack | |
21528 | frame. This information is a tuple that may have the following | |
21529 | fields: | |
21530 | ||
21531 | @table @code | |
21532 | @item level | |
21533 | The level of the stack frame. The innermost frame has the level of | |
21534 | zero. This field is always present. | |
21535 | ||
21536 | @item func | |
21537 | The name of the function corresponding to the frame. This field may | |
21538 | be absent if @value{GDBN} is unable to determine the function name. | |
21539 | ||
21540 | @item addr | |
21541 | The code address for the frame. This field is always present. | |
21542 | ||
21543 | @item file | |
21544 | The name of the source files that correspond to the frame's code | |
21545 | address. This field may be absent. | |
21546 | ||
21547 | @item line | |
21548 | The source line corresponding to the frames' code address. This field | |
21549 | may be absent. | |
21550 | ||
21551 | @item from | |
21552 | The name of the binary file (either executable or shared library) the | |
21553 | corresponds to the frame's code address. This field may be absent. | |
21554 | ||
21555 | @end table | |
82f68b1c | 21556 | |
922fbb7b | 21557 | |
ef21caaf NR |
21558 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21559 | @node GDB/MI Simple Examples | |
21560 | @section Simple Examples of @sc{gdb/mi} Interaction | |
21561 | @cindex @sc{gdb/mi}, simple examples | |
21562 | ||
21563 | This subsection presents several simple examples of interaction using | |
21564 | the @sc{gdb/mi} interface. In these examples, @samp{->} means that the | |
21565 | following line is passed to @sc{gdb/mi} as input, while @samp{<-} means | |
21566 | the output received from @sc{gdb/mi}. | |
21567 | ||
d3e8051b | 21568 | Note the line breaks shown in the examples are here only for |
ef21caaf NR |
21569 | readability, they don't appear in the real output. |
21570 | ||
79a6e687 | 21571 | @subheading Setting a Breakpoint |
ef21caaf NR |
21572 | |
21573 | Setting a breakpoint generates synchronous output which contains detailed | |
21574 | information of the breakpoint. | |
21575 | ||
21576 | @smallexample | |
21577 | -> -break-insert main | |
21578 | <- ^done,bkpt=@{number="1",type="breakpoint",disp="keep", | |
21579 | enabled="y",addr="0x08048564",func="main",file="myprog.c", | |
21580 | fullname="/home/nickrob/myprog.c",line="68",times="0"@} | |
21581 | <- (gdb) | |
21582 | @end smallexample | |
21583 | ||
21584 | @subheading Program Execution | |
21585 | ||
21586 | Program execution generates asynchronous records and MI gives the | |
21587 | reason that execution stopped. | |
21588 | ||
21589 | @smallexample | |
21590 | -> -exec-run | |
21591 | <- ^running | |
21592 | <- (gdb) | |
a47ec5fe | 21593 | <- *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",thread-id="0", |
ef21caaf NR |
21594 | frame=@{addr="0x08048564",func="main", |
21595 | args=[@{name="argc",value="1"@},@{name="argv",value="0xbfc4d4d4"@}], | |
21596 | file="myprog.c",fullname="/home/nickrob/myprog.c",line="68"@} | |
21597 | <- (gdb) | |
21598 | -> -exec-continue | |
21599 | <- ^running | |
21600 | <- (gdb) | |
21601 | <- *stopped,reason="exited-normally" | |
21602 | <- (gdb) | |
21603 | @end smallexample | |
21604 | ||
3f94c067 | 21605 | @subheading Quitting @value{GDBN} |
ef21caaf | 21606 | |
3f94c067 | 21607 | Quitting @value{GDBN} just prints the result class @samp{^exit}. |
ef21caaf NR |
21608 | |
21609 | @smallexample | |
21610 | -> (gdb) | |
21611 | <- -gdb-exit | |
21612 | <- ^exit | |
21613 | @end smallexample | |
21614 | ||
a2c02241 | 21615 | @subheading A Bad Command |
ef21caaf NR |
21616 | |
21617 | Here's what happens if you pass a non-existent command: | |
21618 | ||
21619 | @smallexample | |
21620 | -> -rubbish | |
21621 | <- ^error,msg="Undefined MI command: rubbish" | |
594fe323 | 21622 | <- (gdb) |
ef21caaf NR |
21623 | @end smallexample |
21624 | ||
21625 | ||
922fbb7b AC |
21626 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
21627 | @node GDB/MI Command Description Format | |
21628 | @section @sc{gdb/mi} Command Description Format | |
21629 | ||
21630 | The remaining sections describe blocks of commands. Each block of | |
21631 | commands is laid out in a fashion similar to this section. | |
21632 | ||
922fbb7b AC |
21633 | @subheading Motivation |
21634 | ||
21635 | The motivation for this collection of commands. | |
21636 | ||
21637 | @subheading Introduction | |
21638 | ||
21639 | A brief introduction to this collection of commands as a whole. | |
21640 | ||
21641 | @subheading Commands | |
21642 | ||
21643 | For each command in the block, the following is described: | |
21644 | ||
21645 | @subsubheading Synopsis | |
21646 | ||
21647 | @smallexample | |
21648 | -command @var{args}@dots{} | |
21649 | @end smallexample | |
21650 | ||
922fbb7b AC |
21651 | @subsubheading Result |
21652 | ||
265eeb58 | 21653 | @subsubheading @value{GDBN} Command |
922fbb7b | 21654 | |
265eeb58 | 21655 | The corresponding @value{GDBN} CLI command(s), if any. |
922fbb7b AC |
21656 | |
21657 | @subsubheading Example | |
21658 | ||
ef21caaf NR |
21659 | Example(s) formatted for readability. Some of the described commands have |
21660 | not been implemented yet and these are labeled N.A.@: (not available). | |
21661 | ||
21662 | ||
922fbb7b | 21663 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
ef21caaf NR |
21664 | @node GDB/MI Breakpoint Commands |
21665 | @section @sc{gdb/mi} Breakpoint Commands | |
922fbb7b AC |
21666 | |
21667 | @cindex breakpoint commands for @sc{gdb/mi} | |
21668 | @cindex @sc{gdb/mi}, breakpoint commands | |
21669 | This section documents @sc{gdb/mi} commands for manipulating | |
21670 | breakpoints. | |
21671 | ||
21672 | @subheading The @code{-break-after} Command | |
21673 | @findex -break-after | |
21674 | ||
21675 | @subsubheading Synopsis | |
21676 | ||
21677 | @smallexample | |
21678 | -break-after @var{number} @var{count} | |
21679 | @end smallexample | |
21680 | ||
21681 | The breakpoint number @var{number} is not in effect until it has been | |
21682 | hit @var{count} times. To see how this is reflected in the output of | |
21683 | the @samp{-break-list} command, see the description of the | |
21684 | @samp{-break-list} command below. | |
21685 | ||
21686 | @subsubheading @value{GDBN} Command | |
21687 | ||
21688 | The corresponding @value{GDBN} command is @samp{ignore}. | |
21689 | ||
21690 | @subsubheading Example | |
21691 | ||
21692 | @smallexample | |
594fe323 | 21693 | (gdb) |
922fbb7b | 21694 | -break-insert main |
a47ec5fe AR |
21695 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep", |
21696 | enabled="y",addr="0x000100d0",func="main",file="hello.c", | |
948d5102 | 21697 | fullname="/home/foo/hello.c",line="5",times="0"@} |
594fe323 | 21698 | (gdb) |
922fbb7b AC |
21699 | -break-after 1 3 |
21700 | ~ | |
21701 | ^done | |
594fe323 | 21702 | (gdb) |
922fbb7b AC |
21703 | -break-list |
21704 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
21705 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
21706 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
21707 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
21708 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
21709 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
21710 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
21711 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
21712 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
21713 | line="5",times="0",ignore="3"@}]@} | |
594fe323 | 21714 | (gdb) |
922fbb7b AC |
21715 | @end smallexample |
21716 | ||
21717 | @ignore | |
21718 | @subheading The @code{-break-catch} Command | |
21719 | @findex -break-catch | |
48cb2d85 | 21720 | @end ignore |
922fbb7b AC |
21721 | |
21722 | @subheading The @code{-break-commands} Command | |
21723 | @findex -break-commands | |
922fbb7b | 21724 | |
48cb2d85 VP |
21725 | @subsubheading Synopsis |
21726 | ||
21727 | @smallexample | |
21728 | -break-commands @var{number} [ @var{command1} ... @var{commandN} ] | |
21729 | @end smallexample | |
21730 | ||
21731 | Specifies the CLI commands that should be executed when breakpoint | |
21732 | @var{number} is hit. The parameters @var{command1} to @var{commandN} | |
21733 | are the commands. If no command is specified, any previously-set | |
21734 | commands are cleared. @xref{Break Commands}. Typical use of this | |
21735 | functionality is tracing a program, that is, printing of values of | |
21736 | some variables whenever breakpoint is hit and then continuing. | |
21737 | ||
21738 | @subsubheading @value{GDBN} Command | |
21739 | ||
21740 | The corresponding @value{GDBN} command is @samp{commands}. | |
21741 | ||
21742 | @subsubheading Example | |
21743 | ||
21744 | @smallexample | |
21745 | (gdb) | |
21746 | -break-insert main | |
21747 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep", | |
21748 | enabled="y",addr="0x000100d0",func="main",file="hello.c", | |
21749 | fullname="/home/foo/hello.c",line="5",times="0"@} | |
21750 | (gdb) | |
21751 | -break-commands 1 "print v" "continue" | |
21752 | ^done | |
21753 | (gdb) | |
21754 | @end smallexample | |
922fbb7b AC |
21755 | |
21756 | @subheading The @code{-break-condition} Command | |
21757 | @findex -break-condition | |
21758 | ||
21759 | @subsubheading Synopsis | |
21760 | ||
21761 | @smallexample | |
21762 | -break-condition @var{number} @var{expr} | |
21763 | @end smallexample | |
21764 | ||
21765 | Breakpoint @var{number} will stop the program only if the condition in | |
21766 | @var{expr} is true. The condition becomes part of the | |
21767 | @samp{-break-list} output (see the description of the @samp{-break-list} | |
21768 | command below). | |
21769 | ||
21770 | @subsubheading @value{GDBN} Command | |
21771 | ||
21772 | The corresponding @value{GDBN} command is @samp{condition}. | |
21773 | ||
21774 | @subsubheading Example | |
21775 | ||
21776 | @smallexample | |
594fe323 | 21777 | (gdb) |
922fbb7b AC |
21778 | -break-condition 1 1 |
21779 | ^done | |
594fe323 | 21780 | (gdb) |
922fbb7b AC |
21781 | -break-list |
21782 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
21783 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
21784 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
21785 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
21786 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
21787 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
21788 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
21789 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
21790 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
21791 | line="5",cond="1",times="0",ignore="3"@}]@} | |
594fe323 | 21792 | (gdb) |
922fbb7b AC |
21793 | @end smallexample |
21794 | ||
21795 | @subheading The @code{-break-delete} Command | |
21796 | @findex -break-delete | |
21797 | ||
21798 | @subsubheading Synopsis | |
21799 | ||
21800 | @smallexample | |
21801 | -break-delete ( @var{breakpoint} )+ | |
21802 | @end smallexample | |
21803 | ||
21804 | Delete the breakpoint(s) whose number(s) are specified in the argument | |
21805 | list. This is obviously reflected in the breakpoint list. | |
21806 | ||
79a6e687 | 21807 | @subsubheading @value{GDBN} Command |
922fbb7b AC |
21808 | |
21809 | The corresponding @value{GDBN} command is @samp{delete}. | |
21810 | ||
21811 | @subsubheading Example | |
21812 | ||
21813 | @smallexample | |
594fe323 | 21814 | (gdb) |
922fbb7b AC |
21815 | -break-delete 1 |
21816 | ^done | |
594fe323 | 21817 | (gdb) |
922fbb7b AC |
21818 | -break-list |
21819 | ^done,BreakpointTable=@{nr_rows="0",nr_cols="6", | |
21820 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
21821 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
21822 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
21823 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
21824 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
21825 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
21826 | body=[]@} | |
594fe323 | 21827 | (gdb) |
922fbb7b AC |
21828 | @end smallexample |
21829 | ||
21830 | @subheading The @code{-break-disable} Command | |
21831 | @findex -break-disable | |
21832 | ||
21833 | @subsubheading Synopsis | |
21834 | ||
21835 | @smallexample | |
21836 | -break-disable ( @var{breakpoint} )+ | |
21837 | @end smallexample | |
21838 | ||
21839 | Disable the named @var{breakpoint}(s). The field @samp{enabled} in the | |
21840 | break list is now set to @samp{n} for the named @var{breakpoint}(s). | |
21841 | ||
21842 | @subsubheading @value{GDBN} Command | |
21843 | ||
21844 | The corresponding @value{GDBN} command is @samp{disable}. | |
21845 | ||
21846 | @subsubheading Example | |
21847 | ||
21848 | @smallexample | |
594fe323 | 21849 | (gdb) |
922fbb7b AC |
21850 | -break-disable 2 |
21851 | ^done | |
594fe323 | 21852 | (gdb) |
922fbb7b AC |
21853 | -break-list |
21854 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
21855 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
21856 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
21857 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
21858 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
21859 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
21860 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
21861 | body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="n", | |
948d5102 NR |
21862 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
21863 | line="5",times="0"@}]@} | |
594fe323 | 21864 | (gdb) |
922fbb7b AC |
21865 | @end smallexample |
21866 | ||
21867 | @subheading The @code{-break-enable} Command | |
21868 | @findex -break-enable | |
21869 | ||
21870 | @subsubheading Synopsis | |
21871 | ||
21872 | @smallexample | |
21873 | -break-enable ( @var{breakpoint} )+ | |
21874 | @end smallexample | |
21875 | ||
21876 | Enable (previously disabled) @var{breakpoint}(s). | |
21877 | ||
21878 | @subsubheading @value{GDBN} Command | |
21879 | ||
21880 | The corresponding @value{GDBN} command is @samp{enable}. | |
21881 | ||
21882 | @subsubheading Example | |
21883 | ||
21884 | @smallexample | |
594fe323 | 21885 | (gdb) |
922fbb7b AC |
21886 | -break-enable 2 |
21887 | ^done | |
594fe323 | 21888 | (gdb) |
922fbb7b AC |
21889 | -break-list |
21890 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
21891 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
21892 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
21893 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
21894 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
21895 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
21896 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
21897 | body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
21898 | addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c", |
21899 | line="5",times="0"@}]@} | |
594fe323 | 21900 | (gdb) |
922fbb7b AC |
21901 | @end smallexample |
21902 | ||
21903 | @subheading The @code{-break-info} Command | |
21904 | @findex -break-info | |
21905 | ||
21906 | @subsubheading Synopsis | |
21907 | ||
21908 | @smallexample | |
21909 | -break-info @var{breakpoint} | |
21910 | @end smallexample | |
21911 | ||
21912 | @c REDUNDANT??? | |
21913 | Get information about a single breakpoint. | |
21914 | ||
79a6e687 | 21915 | @subsubheading @value{GDBN} Command |
922fbb7b AC |
21916 | |
21917 | The corresponding @value{GDBN} command is @samp{info break @var{breakpoint}}. | |
21918 | ||
21919 | @subsubheading Example | |
21920 | N.A. | |
21921 | ||
21922 | @subheading The @code{-break-insert} Command | |
21923 | @findex -break-insert | |
21924 | ||
21925 | @subsubheading Synopsis | |
21926 | ||
21927 | @smallexample | |
41447f92 | 21928 | -break-insert [ -t ] [ -h ] [ -f ] [ -d ] |
922fbb7b | 21929 | [ -c @var{condition} ] [ -i @var{ignore-count} ] |
afe8ab22 | 21930 | [ -p @var{thread} ] [ @var{location} ] |
922fbb7b AC |
21931 | @end smallexample |
21932 | ||
21933 | @noindent | |
afe8ab22 | 21934 | If specified, @var{location}, can be one of: |
922fbb7b AC |
21935 | |
21936 | @itemize @bullet | |
21937 | @item function | |
21938 | @c @item +offset | |
21939 | @c @item -offset | |
21940 | @c @item linenum | |
21941 | @item filename:linenum | |
21942 | @item filename:function | |
21943 | @item *address | |
21944 | @end itemize | |
21945 | ||
21946 | The possible optional parameters of this command are: | |
21947 | ||
21948 | @table @samp | |
21949 | @item -t | |
948d5102 | 21950 | Insert a temporary breakpoint. |
922fbb7b AC |
21951 | @item -h |
21952 | Insert a hardware breakpoint. | |
21953 | @item -c @var{condition} | |
21954 | Make the breakpoint conditional on @var{condition}. | |
21955 | @item -i @var{ignore-count} | |
21956 | Initialize the @var{ignore-count}. | |
afe8ab22 VP |
21957 | @item -f |
21958 | If @var{location} cannot be parsed (for example if it | |
21959 | refers to unknown files or functions), create a pending | |
21960 | breakpoint. Without this flag, @value{GDBN} will report | |
21961 | an error, and won't create a breakpoint, if @var{location} | |
21962 | cannot be parsed. | |
41447f92 VP |
21963 | @item -d |
21964 | Create a disabled breakpoint. | |
922fbb7b AC |
21965 | @end table |
21966 | ||
21967 | @subsubheading Result | |
21968 | ||
21969 | The result is in the form: | |
21970 | ||
21971 | @smallexample | |
948d5102 NR |
21972 | ^done,bkpt=@{number="@var{number}",type="@var{type}",disp="del"|"keep", |
21973 | enabled="y"|"n",addr="@var{hex}",func="@var{funcname}",file="@var{filename}", | |
ef21caaf NR |
21974 | fullname="@var{full_filename}",line="@var{lineno}",[thread="@var{threadno},] |
21975 | times="@var{times}"@} | |
922fbb7b AC |
21976 | @end smallexample |
21977 | ||
21978 | @noindent | |
948d5102 NR |
21979 | where @var{number} is the @value{GDBN} number for this breakpoint, |
21980 | @var{funcname} is the name of the function where the breakpoint was | |
21981 | inserted, @var{filename} is the name of the source file which contains | |
21982 | this function, @var{lineno} is the source line number within that file | |
21983 | and @var{times} the number of times that the breakpoint has been hit | |
21984 | (always 0 for -break-insert but may be greater for -break-info or -break-list | |
21985 | which use the same output). | |
922fbb7b AC |
21986 | |
21987 | Note: this format is open to change. | |
21988 | @c An out-of-band breakpoint instead of part of the result? | |
21989 | ||
21990 | @subsubheading @value{GDBN} Command | |
21991 | ||
21992 | The corresponding @value{GDBN} commands are @samp{break}, @samp{tbreak}, | |
21993 | @samp{hbreak}, @samp{thbreak}, and @samp{rbreak}. | |
21994 | ||
21995 | @subsubheading Example | |
21996 | ||
21997 | @smallexample | |
594fe323 | 21998 | (gdb) |
922fbb7b | 21999 | -break-insert main |
948d5102 NR |
22000 | ^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c", |
22001 | fullname="/home/foo/recursive2.c,line="4",times="0"@} | |
594fe323 | 22002 | (gdb) |
922fbb7b | 22003 | -break-insert -t foo |
948d5102 NR |
22004 | ^done,bkpt=@{number="2",addr="0x00010774",file="recursive2.c", |
22005 | fullname="/home/foo/recursive2.c,line="11",times="0"@} | |
594fe323 | 22006 | (gdb) |
922fbb7b AC |
22007 | -break-list |
22008 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22009 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22010 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22011 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22012 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22013 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22014 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22015 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22016 | addr="0x0001072c", func="main",file="recursive2.c", |
22017 | fullname="/home/foo/recursive2.c,"line="4",times="0"@}, | |
922fbb7b | 22018 | bkpt=@{number="2",type="breakpoint",disp="del",enabled="y", |
948d5102 NR |
22019 | addr="0x00010774",func="foo",file="recursive2.c", |
22020 | fullname="/home/foo/recursive2.c",line="11",times="0"@}]@} | |
594fe323 | 22021 | (gdb) |
922fbb7b AC |
22022 | -break-insert -r foo.* |
22023 | ~int foo(int, int); | |
948d5102 NR |
22024 | ^done,bkpt=@{number="3",addr="0x00010774",file="recursive2.c, |
22025 | "fullname="/home/foo/recursive2.c",line="11",times="0"@} | |
594fe323 | 22026 | (gdb) |
922fbb7b AC |
22027 | @end smallexample |
22028 | ||
22029 | @subheading The @code{-break-list} Command | |
22030 | @findex -break-list | |
22031 | ||
22032 | @subsubheading Synopsis | |
22033 | ||
22034 | @smallexample | |
22035 | -break-list | |
22036 | @end smallexample | |
22037 | ||
22038 | Displays the list of inserted breakpoints, showing the following fields: | |
22039 | ||
22040 | @table @samp | |
22041 | @item Number | |
22042 | number of the breakpoint | |
22043 | @item Type | |
22044 | type of the breakpoint: @samp{breakpoint} or @samp{watchpoint} | |
22045 | @item Disposition | |
22046 | should the breakpoint be deleted or disabled when it is hit: @samp{keep} | |
22047 | or @samp{nokeep} | |
22048 | @item Enabled | |
22049 | is the breakpoint enabled or no: @samp{y} or @samp{n} | |
22050 | @item Address | |
22051 | memory location at which the breakpoint is set | |
22052 | @item What | |
22053 | logical location of the breakpoint, expressed by function name, file | |
22054 | name, line number | |
22055 | @item Times | |
22056 | number of times the breakpoint has been hit | |
22057 | @end table | |
22058 | ||
22059 | If there are no breakpoints or watchpoints, the @code{BreakpointTable} | |
22060 | @code{body} field is an empty list. | |
22061 | ||
22062 | @subsubheading @value{GDBN} Command | |
22063 | ||
22064 | The corresponding @value{GDBN} command is @samp{info break}. | |
22065 | ||
22066 | @subsubheading Example | |
22067 | ||
22068 | @smallexample | |
594fe323 | 22069 | (gdb) |
922fbb7b AC |
22070 | -break-list |
22071 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22072 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22073 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22074 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22075 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22076 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22077 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22078 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22079 | addr="0x000100d0",func="main",file="hello.c",line="5",times="0"@}, | |
22080 | bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y", | |
948d5102 NR |
22081 | addr="0x00010114",func="foo",file="hello.c",fullname="/home/foo/hello.c", |
22082 | line="13",times="0"@}]@} | |
594fe323 | 22083 | (gdb) |
922fbb7b AC |
22084 | @end smallexample |
22085 | ||
22086 | Here's an example of the result when there are no breakpoints: | |
22087 | ||
22088 | @smallexample | |
594fe323 | 22089 | (gdb) |
922fbb7b AC |
22090 | -break-list |
22091 | ^done,BreakpointTable=@{nr_rows="0",nr_cols="6", | |
22092 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22093 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22094 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22095 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22096 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22097 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22098 | body=[]@} | |
594fe323 | 22099 | (gdb) |
922fbb7b AC |
22100 | @end smallexample |
22101 | ||
22102 | @subheading The @code{-break-watch} Command | |
22103 | @findex -break-watch | |
22104 | ||
22105 | @subsubheading Synopsis | |
22106 | ||
22107 | @smallexample | |
22108 | -break-watch [ -a | -r ] | |
22109 | @end smallexample | |
22110 | ||
22111 | Create a watchpoint. With the @samp{-a} option it will create an | |
d3e8051b | 22112 | @dfn{access} watchpoint, i.e., a watchpoint that triggers either on a |
922fbb7b | 22113 | read from or on a write to the memory location. With the @samp{-r} |
d3e8051b | 22114 | option, the watchpoint created is a @dfn{read} watchpoint, i.e., it will |
922fbb7b AC |
22115 | trigger only when the memory location is accessed for reading. Without |
22116 | either of the options, the watchpoint created is a regular watchpoint, | |
d3e8051b | 22117 | i.e., it will trigger when the memory location is accessed for writing. |
79a6e687 | 22118 | @xref{Set Watchpoints, , Setting Watchpoints}. |
922fbb7b AC |
22119 | |
22120 | Note that @samp{-break-list} will report a single list of watchpoints and | |
22121 | breakpoints inserted. | |
22122 | ||
22123 | @subsubheading @value{GDBN} Command | |
22124 | ||
22125 | The corresponding @value{GDBN} commands are @samp{watch}, @samp{awatch}, and | |
22126 | @samp{rwatch}. | |
22127 | ||
22128 | @subsubheading Example | |
22129 | ||
22130 | Setting a watchpoint on a variable in the @code{main} function: | |
22131 | ||
22132 | @smallexample | |
594fe323 | 22133 | (gdb) |
922fbb7b AC |
22134 | -break-watch x |
22135 | ^done,wpt=@{number="2",exp="x"@} | |
594fe323 | 22136 | (gdb) |
922fbb7b AC |
22137 | -exec-continue |
22138 | ^running | |
0869d01b NR |
22139 | (gdb) |
22140 | *stopped,reason="watchpoint-trigger",wpt=@{number="2",exp="x"@}, | |
922fbb7b | 22141 | value=@{old="-268439212",new="55"@}, |
76ff342d | 22142 | frame=@{func="main",args=[],file="recursive2.c", |
948d5102 | 22143 | fullname="/home/foo/bar/recursive2.c",line="5"@} |
594fe323 | 22144 | (gdb) |
922fbb7b AC |
22145 | @end smallexample |
22146 | ||
22147 | Setting a watchpoint on a variable local to a function. @value{GDBN} will stop | |
22148 | the program execution twice: first for the variable changing value, then | |
22149 | for the watchpoint going out of scope. | |
22150 | ||
22151 | @smallexample | |
594fe323 | 22152 | (gdb) |
922fbb7b AC |
22153 | -break-watch C |
22154 | ^done,wpt=@{number="5",exp="C"@} | |
594fe323 | 22155 | (gdb) |
922fbb7b AC |
22156 | -exec-continue |
22157 | ^running | |
0869d01b NR |
22158 | (gdb) |
22159 | *stopped,reason="watchpoint-trigger", | |
922fbb7b AC |
22160 | wpt=@{number="5",exp="C"@},value=@{old="-276895068",new="3"@}, |
22161 | frame=@{func="callee4",args=[], | |
76ff342d DJ |
22162 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22163 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@} | |
594fe323 | 22164 | (gdb) |
922fbb7b AC |
22165 | -exec-continue |
22166 | ^running | |
0869d01b NR |
22167 | (gdb) |
22168 | *stopped,reason="watchpoint-scope",wpnum="5", | |
922fbb7b AC |
22169 | frame=@{func="callee3",args=[@{name="strarg", |
22170 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
22171 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22172 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 22173 | (gdb) |
922fbb7b AC |
22174 | @end smallexample |
22175 | ||
22176 | Listing breakpoints and watchpoints, at different points in the program | |
22177 | execution. Note that once the watchpoint goes out of scope, it is | |
22178 | deleted. | |
22179 | ||
22180 | @smallexample | |
594fe323 | 22181 | (gdb) |
922fbb7b AC |
22182 | -break-watch C |
22183 | ^done,wpt=@{number="2",exp="C"@} | |
594fe323 | 22184 | (gdb) |
922fbb7b AC |
22185 | -break-list |
22186 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22187 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22188 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22189 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22190 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22191 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22192 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22193 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22194 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22195 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22196 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c"line="8",times="1"@}, | |
922fbb7b AC |
22197 | bkpt=@{number="2",type="watchpoint",disp="keep", |
22198 | enabled="y",addr="",what="C",times="0"@}]@} | |
594fe323 | 22199 | (gdb) |
922fbb7b AC |
22200 | -exec-continue |
22201 | ^running | |
0869d01b NR |
22202 | (gdb) |
22203 | *stopped,reason="watchpoint-trigger",wpt=@{number="2",exp="C"@}, | |
922fbb7b AC |
22204 | value=@{old="-276895068",new="3"@}, |
22205 | frame=@{func="callee4",args=[], | |
76ff342d DJ |
22206 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22207 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@} | |
594fe323 | 22208 | (gdb) |
922fbb7b AC |
22209 | -break-list |
22210 | ^done,BreakpointTable=@{nr_rows="2",nr_cols="6", | |
22211 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22212 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22213 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22214 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22215 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22216 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22217 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22218 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22219 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22220 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"@}, | |
922fbb7b AC |
22221 | bkpt=@{number="2",type="watchpoint",disp="keep", |
22222 | enabled="y",addr="",what="C",times="-5"@}]@} | |
594fe323 | 22223 | (gdb) |
922fbb7b AC |
22224 | -exec-continue |
22225 | ^running | |
22226 | ^done,reason="watchpoint-scope",wpnum="2", | |
22227 | frame=@{func="callee3",args=[@{name="strarg", | |
22228 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
22229 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22230 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 22231 | (gdb) |
922fbb7b AC |
22232 | -break-list |
22233 | ^done,BreakpointTable=@{nr_rows="1",nr_cols="6", | |
22234 | hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@}, | |
22235 | @{width="14",alignment="-1",col_name="type",colhdr="Type"@}, | |
22236 | @{width="4",alignment="-1",col_name="disp",colhdr="Disp"@}, | |
22237 | @{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@}, | |
22238 | @{width="10",alignment="-1",col_name="addr",colhdr="Address"@}, | |
22239 | @{width="40",alignment="2",col_name="what",colhdr="What"@}], | |
22240 | body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
22241 | addr="0x00010734",func="callee4", | |
948d5102 NR |
22242 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22243 | fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8", | |
22244 | times="1"@}]@} | |
594fe323 | 22245 | (gdb) |
922fbb7b AC |
22246 | @end smallexample |
22247 | ||
22248 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
a2c02241 NR |
22249 | @node GDB/MI Program Context |
22250 | @section @sc{gdb/mi} Program Context | |
922fbb7b | 22251 | |
a2c02241 NR |
22252 | @subheading The @code{-exec-arguments} Command |
22253 | @findex -exec-arguments | |
922fbb7b | 22254 | |
922fbb7b AC |
22255 | |
22256 | @subsubheading Synopsis | |
22257 | ||
22258 | @smallexample | |
a2c02241 | 22259 | -exec-arguments @var{args} |
922fbb7b AC |
22260 | @end smallexample |
22261 | ||
a2c02241 NR |
22262 | Set the inferior program arguments, to be used in the next |
22263 | @samp{-exec-run}. | |
922fbb7b | 22264 | |
a2c02241 | 22265 | @subsubheading @value{GDBN} Command |
922fbb7b | 22266 | |
a2c02241 | 22267 | The corresponding @value{GDBN} command is @samp{set args}. |
922fbb7b | 22268 | |
a2c02241 | 22269 | @subsubheading Example |
922fbb7b | 22270 | |
fbc5282e MK |
22271 | @smallexample |
22272 | (gdb) | |
22273 | -exec-arguments -v word | |
22274 | ^done | |
22275 | (gdb) | |
22276 | @end smallexample | |
922fbb7b | 22277 | |
a2c02241 | 22278 | |
9901a55b | 22279 | @ignore |
a2c02241 NR |
22280 | @subheading The @code{-exec-show-arguments} Command |
22281 | @findex -exec-show-arguments | |
22282 | ||
22283 | @subsubheading Synopsis | |
22284 | ||
22285 | @smallexample | |
22286 | -exec-show-arguments | |
22287 | @end smallexample | |
22288 | ||
22289 | Print the arguments of the program. | |
922fbb7b AC |
22290 | |
22291 | @subsubheading @value{GDBN} Command | |
22292 | ||
a2c02241 | 22293 | The corresponding @value{GDBN} command is @samp{show args}. |
922fbb7b AC |
22294 | |
22295 | @subsubheading Example | |
a2c02241 | 22296 | N.A. |
9901a55b | 22297 | @end ignore |
922fbb7b | 22298 | |
922fbb7b | 22299 | |
a2c02241 NR |
22300 | @subheading The @code{-environment-cd} Command |
22301 | @findex -environment-cd | |
922fbb7b | 22302 | |
a2c02241 | 22303 | @subsubheading Synopsis |
922fbb7b AC |
22304 | |
22305 | @smallexample | |
a2c02241 | 22306 | -environment-cd @var{pathdir} |
922fbb7b AC |
22307 | @end smallexample |
22308 | ||
a2c02241 | 22309 | Set @value{GDBN}'s working directory. |
922fbb7b | 22310 | |
a2c02241 | 22311 | @subsubheading @value{GDBN} Command |
922fbb7b | 22312 | |
a2c02241 NR |
22313 | The corresponding @value{GDBN} command is @samp{cd}. |
22314 | ||
22315 | @subsubheading Example | |
922fbb7b AC |
22316 | |
22317 | @smallexample | |
594fe323 | 22318 | (gdb) |
a2c02241 NR |
22319 | -environment-cd /kwikemart/marge/ezannoni/flathead-dev/devo/gdb |
22320 | ^done | |
594fe323 | 22321 | (gdb) |
922fbb7b AC |
22322 | @end smallexample |
22323 | ||
22324 | ||
a2c02241 NR |
22325 | @subheading The @code{-environment-directory} Command |
22326 | @findex -environment-directory | |
922fbb7b AC |
22327 | |
22328 | @subsubheading Synopsis | |
22329 | ||
22330 | @smallexample | |
a2c02241 | 22331 | -environment-directory [ -r ] [ @var{pathdir} ]+ |
922fbb7b AC |
22332 | @end smallexample |
22333 | ||
a2c02241 NR |
22334 | Add directories @var{pathdir} to beginning of search path for source files. |
22335 | If the @samp{-r} option is used, the search path is reset to the default | |
22336 | search path. If directories @var{pathdir} are supplied in addition to the | |
22337 | @samp{-r} option, the search path is first reset and then addition | |
22338 | occurs as normal. | |
22339 | Multiple directories may be specified, separated by blanks. Specifying | |
22340 | multiple directories in a single command | |
22341 | results in the directories added to the beginning of the | |
22342 | search path in the same order they were presented in the command. | |
22343 | If blanks are needed as | |
22344 | part of a directory name, double-quotes should be used around | |
22345 | the name. In the command output, the path will show up separated | |
d3e8051b | 22346 | by the system directory-separator character. The directory-separator |
a2c02241 NR |
22347 | character must not be used |
22348 | in any directory name. | |
22349 | If no directories are specified, the current search path is displayed. | |
922fbb7b AC |
22350 | |
22351 | @subsubheading @value{GDBN} Command | |
22352 | ||
a2c02241 | 22353 | The corresponding @value{GDBN} command is @samp{dir}. |
922fbb7b AC |
22354 | |
22355 | @subsubheading Example | |
22356 | ||
922fbb7b | 22357 | @smallexample |
594fe323 | 22358 | (gdb) |
a2c02241 NR |
22359 | -environment-directory /kwikemart/marge/ezannoni/flathead-dev/devo/gdb |
22360 | ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" | |
594fe323 | 22361 | (gdb) |
a2c02241 NR |
22362 | -environment-directory "" |
22363 | ^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd" | |
594fe323 | 22364 | (gdb) |
a2c02241 NR |
22365 | -environment-directory -r /home/jjohnstn/src/gdb /usr/src |
22366 | ^done,source-path="/home/jjohnstn/src/gdb:/usr/src:$cdir:$cwd" | |
594fe323 | 22367 | (gdb) |
a2c02241 NR |
22368 | -environment-directory -r |
22369 | ^done,source-path="$cdir:$cwd" | |
594fe323 | 22370 | (gdb) |
922fbb7b AC |
22371 | @end smallexample |
22372 | ||
22373 | ||
a2c02241 NR |
22374 | @subheading The @code{-environment-path} Command |
22375 | @findex -environment-path | |
922fbb7b AC |
22376 | |
22377 | @subsubheading Synopsis | |
22378 | ||
22379 | @smallexample | |
a2c02241 | 22380 | -environment-path [ -r ] [ @var{pathdir} ]+ |
922fbb7b AC |
22381 | @end smallexample |
22382 | ||
a2c02241 NR |
22383 | Add directories @var{pathdir} to beginning of search path for object files. |
22384 | If the @samp{-r} option is used, the search path is reset to the original | |
22385 | search path that existed at gdb start-up. If directories @var{pathdir} are | |
22386 | supplied in addition to the | |
22387 | @samp{-r} option, the search path is first reset and then addition | |
22388 | occurs as normal. | |
22389 | Multiple directories may be specified, separated by blanks. Specifying | |
22390 | multiple directories in a single command | |
22391 | results in the directories added to the beginning of the | |
22392 | search path in the same order they were presented in the command. | |
22393 | If blanks are needed as | |
22394 | part of a directory name, double-quotes should be used around | |
22395 | the name. In the command output, the path will show up separated | |
d3e8051b | 22396 | by the system directory-separator character. The directory-separator |
a2c02241 NR |
22397 | character must not be used |
22398 | in any directory name. | |
22399 | If no directories are specified, the current path is displayed. | |
22400 | ||
922fbb7b AC |
22401 | |
22402 | @subsubheading @value{GDBN} Command | |
22403 | ||
a2c02241 | 22404 | The corresponding @value{GDBN} command is @samp{path}. |
922fbb7b AC |
22405 | |
22406 | @subsubheading Example | |
22407 | ||
922fbb7b | 22408 | @smallexample |
594fe323 | 22409 | (gdb) |
a2c02241 NR |
22410 | -environment-path |
22411 | ^done,path="/usr/bin" | |
594fe323 | 22412 | (gdb) |
a2c02241 NR |
22413 | -environment-path /kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb /bin |
22414 | ^done,path="/kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb:/bin:/usr/bin" | |
594fe323 | 22415 | (gdb) |
a2c02241 NR |
22416 | -environment-path -r /usr/local/bin |
22417 | ^done,path="/usr/local/bin:/usr/bin" | |
594fe323 | 22418 | (gdb) |
922fbb7b AC |
22419 | @end smallexample |
22420 | ||
22421 | ||
a2c02241 NR |
22422 | @subheading The @code{-environment-pwd} Command |
22423 | @findex -environment-pwd | |
922fbb7b AC |
22424 | |
22425 | @subsubheading Synopsis | |
22426 | ||
22427 | @smallexample | |
a2c02241 | 22428 | -environment-pwd |
922fbb7b AC |
22429 | @end smallexample |
22430 | ||
a2c02241 | 22431 | Show the current working directory. |
922fbb7b | 22432 | |
79a6e687 | 22433 | @subsubheading @value{GDBN} Command |
922fbb7b | 22434 | |
a2c02241 | 22435 | The corresponding @value{GDBN} command is @samp{pwd}. |
922fbb7b AC |
22436 | |
22437 | @subsubheading Example | |
22438 | ||
922fbb7b | 22439 | @smallexample |
594fe323 | 22440 | (gdb) |
a2c02241 NR |
22441 | -environment-pwd |
22442 | ^done,cwd="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb" | |
594fe323 | 22443 | (gdb) |
922fbb7b AC |
22444 | @end smallexample |
22445 | ||
a2c02241 NR |
22446 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
22447 | @node GDB/MI Thread Commands | |
22448 | @section @sc{gdb/mi} Thread Commands | |
22449 | ||
22450 | ||
22451 | @subheading The @code{-thread-info} Command | |
22452 | @findex -thread-info | |
922fbb7b AC |
22453 | |
22454 | @subsubheading Synopsis | |
22455 | ||
22456 | @smallexample | |
8e8901c5 | 22457 | -thread-info [ @var{thread-id} ] |
922fbb7b AC |
22458 | @end smallexample |
22459 | ||
8e8901c5 VP |
22460 | Reports information about either a specific thread, if |
22461 | the @var{thread-id} parameter is present, or about all | |
22462 | threads. When printing information about all threads, | |
22463 | also reports the current thread. | |
22464 | ||
79a6e687 | 22465 | @subsubheading @value{GDBN} Command |
922fbb7b | 22466 | |
8e8901c5 VP |
22467 | The @samp{info thread} command prints the same information |
22468 | about all threads. | |
922fbb7b AC |
22469 | |
22470 | @subsubheading Example | |
922fbb7b AC |
22471 | |
22472 | @smallexample | |
8e8901c5 VP |
22473 | -thread-info |
22474 | ^done,threads=[ | |
22475 | @{id="2",target-id="Thread 0xb7e14b90 (LWP 21257)", | |
c3b108f7 | 22476 | frame=@{level="0",addr="0xffffe410",func="__kernel_vsyscall",args=[]@},state="running"@}, |
8e8901c5 VP |
22477 | @{id="1",target-id="Thread 0xb7e156b0 (LWP 21254)", |
22478 | frame=@{level="0",addr="0x0804891f",func="foo",args=[@{name="i",value="10"@}], | |
c3b108f7 | 22479 | file="/tmp/a.c",fullname="/tmp/a.c",line="158"@},state="running"@}], |
8e8901c5 VP |
22480 | current-thread-id="1" |
22481 | (gdb) | |
922fbb7b AC |
22482 | @end smallexample |
22483 | ||
c3b108f7 VP |
22484 | The @samp{state} field may have the following values: |
22485 | ||
22486 | @table @code | |
22487 | @item stopped | |
22488 | The thread is stopped. Frame information is available for stopped | |
22489 | threads. | |
22490 | ||
22491 | @item running | |
22492 | The thread is running. There's no frame information for running | |
22493 | threads. | |
22494 | ||
22495 | @end table | |
22496 | ||
a2c02241 NR |
22497 | @subheading The @code{-thread-list-ids} Command |
22498 | @findex -thread-list-ids | |
922fbb7b | 22499 | |
a2c02241 | 22500 | @subsubheading Synopsis |
922fbb7b | 22501 | |
a2c02241 NR |
22502 | @smallexample |
22503 | -thread-list-ids | |
22504 | @end smallexample | |
922fbb7b | 22505 | |
a2c02241 NR |
22506 | Produces a list of the currently known @value{GDBN} thread ids. At the |
22507 | end of the list it also prints the total number of such threads. | |
922fbb7b | 22508 | |
c3b108f7 VP |
22509 | This command is retained for historical reasons, the |
22510 | @code{-thread-info} command should be used instead. | |
22511 | ||
922fbb7b AC |
22512 | @subsubheading @value{GDBN} Command |
22513 | ||
a2c02241 | 22514 | Part of @samp{info threads} supplies the same information. |
922fbb7b AC |
22515 | |
22516 | @subsubheading Example | |
22517 | ||
922fbb7b | 22518 | @smallexample |
594fe323 | 22519 | (gdb) |
a2c02241 NR |
22520 | -thread-list-ids |
22521 | ^done,thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@}, | |
592375cd | 22522 | current-thread-id="1",number-of-threads="3" |
594fe323 | 22523 | (gdb) |
922fbb7b AC |
22524 | @end smallexample |
22525 | ||
a2c02241 NR |
22526 | |
22527 | @subheading The @code{-thread-select} Command | |
22528 | @findex -thread-select | |
922fbb7b AC |
22529 | |
22530 | @subsubheading Synopsis | |
22531 | ||
22532 | @smallexample | |
a2c02241 | 22533 | -thread-select @var{threadnum} |
922fbb7b AC |
22534 | @end smallexample |
22535 | ||
a2c02241 NR |
22536 | Make @var{threadnum} the current thread. It prints the number of the new |
22537 | current thread, and the topmost frame for that thread. | |
922fbb7b | 22538 | |
c3b108f7 VP |
22539 | This command is deprecated in favor of explicitly using the |
22540 | @samp{--thread} option to each command. | |
22541 | ||
922fbb7b AC |
22542 | @subsubheading @value{GDBN} Command |
22543 | ||
a2c02241 | 22544 | The corresponding @value{GDBN} command is @samp{thread}. |
922fbb7b AC |
22545 | |
22546 | @subsubheading Example | |
922fbb7b AC |
22547 | |
22548 | @smallexample | |
594fe323 | 22549 | (gdb) |
a2c02241 NR |
22550 | -exec-next |
22551 | ^running | |
594fe323 | 22552 | (gdb) |
a2c02241 NR |
22553 | *stopped,reason="end-stepping-range",thread-id="2",line="187", |
22554 | file="../../../devo/gdb/testsuite/gdb.threads/linux-dp.c" | |
594fe323 | 22555 | (gdb) |
a2c02241 NR |
22556 | -thread-list-ids |
22557 | ^done, | |
22558 | thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@}, | |
22559 | number-of-threads="3" | |
594fe323 | 22560 | (gdb) |
a2c02241 NR |
22561 | -thread-select 3 |
22562 | ^done,new-thread-id="3", | |
22563 | frame=@{level="0",func="vprintf", | |
22564 | args=[@{name="format",value="0x8048e9c \"%*s%c %d %c\\n\""@}, | |
22565 | @{name="arg",value="0x2"@}],file="vprintf.c",line="31"@} | |
594fe323 | 22566 | (gdb) |
922fbb7b AC |
22567 | @end smallexample |
22568 | ||
a2c02241 NR |
22569 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
22570 | @node GDB/MI Program Execution | |
22571 | @section @sc{gdb/mi} Program Execution | |
922fbb7b | 22572 | |
ef21caaf | 22573 | These are the asynchronous commands which generate the out-of-band |
3f94c067 | 22574 | record @samp{*stopped}. Currently @value{GDBN} only really executes |
ef21caaf NR |
22575 | asynchronously with remote targets and this interaction is mimicked in |
22576 | other cases. | |
922fbb7b | 22577 | |
922fbb7b AC |
22578 | @subheading The @code{-exec-continue} Command |
22579 | @findex -exec-continue | |
22580 | ||
22581 | @subsubheading Synopsis | |
22582 | ||
22583 | @smallexample | |
c3b108f7 | 22584 | -exec-continue [--all|--thread-group N] |
922fbb7b AC |
22585 | @end smallexample |
22586 | ||
ef21caaf | 22587 | Resumes the execution of the inferior program until a breakpoint is |
c3b108f7 VP |
22588 | encountered, or until the inferior exits. In all-stop mode |
22589 | (@pxref{All-Stop Mode}), may resume only one thread, or all threads, | |
22590 | depending on the value of the @samp{scheduler-locking} variable. In | |
22591 | non-stop mode (@pxref{Non-Stop Mode}), if the @samp{--all} is not | |
22592 | specified, only the thread specified with the @samp{--thread} option | |
22593 | (or current thread, if no @samp{--thread} is provided) is resumed. If | |
22594 | @samp{--all} is specified, all threads will be resumed. The | |
22595 | @samp{--all} option is ignored in all-stop mode. If the | |
22596 | @samp{--thread-group} options is specified, then all threads in that | |
22597 | thread group are resumed. | |
922fbb7b AC |
22598 | |
22599 | @subsubheading @value{GDBN} Command | |
22600 | ||
22601 | The corresponding @value{GDBN} corresponding is @samp{continue}. | |
22602 | ||
22603 | @subsubheading Example | |
22604 | ||
22605 | @smallexample | |
22606 | -exec-continue | |
22607 | ^running | |
594fe323 | 22608 | (gdb) |
922fbb7b | 22609 | @@Hello world |
a47ec5fe AR |
22610 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="2",frame=@{ |
22611 | func="foo",args=[],file="hello.c",fullname="/home/foo/bar/hello.c", | |
22612 | line="13"@} | |
594fe323 | 22613 | (gdb) |
922fbb7b AC |
22614 | @end smallexample |
22615 | ||
22616 | ||
22617 | @subheading The @code{-exec-finish} Command | |
22618 | @findex -exec-finish | |
22619 | ||
22620 | @subsubheading Synopsis | |
22621 | ||
22622 | @smallexample | |
22623 | -exec-finish | |
22624 | @end smallexample | |
22625 | ||
ef21caaf NR |
22626 | Resumes the execution of the inferior program until the current |
22627 | function is exited. Displays the results returned by the function. | |
922fbb7b AC |
22628 | |
22629 | @subsubheading @value{GDBN} Command | |
22630 | ||
22631 | The corresponding @value{GDBN} command is @samp{finish}. | |
22632 | ||
22633 | @subsubheading Example | |
22634 | ||
22635 | Function returning @code{void}. | |
22636 | ||
22637 | @smallexample | |
22638 | -exec-finish | |
22639 | ^running | |
594fe323 | 22640 | (gdb) |
922fbb7b AC |
22641 | @@hello from foo |
22642 | *stopped,reason="function-finished",frame=@{func="main",args=[], | |
948d5102 | 22643 | file="hello.c",fullname="/home/foo/bar/hello.c",line="7"@} |
594fe323 | 22644 | (gdb) |
922fbb7b AC |
22645 | @end smallexample |
22646 | ||
22647 | Function returning other than @code{void}. The name of the internal | |
22648 | @value{GDBN} variable storing the result is printed, together with the | |
22649 | value itself. | |
22650 | ||
22651 | @smallexample | |
22652 | -exec-finish | |
22653 | ^running | |
594fe323 | 22654 | (gdb) |
922fbb7b AC |
22655 | *stopped,reason="function-finished",frame=@{addr="0x000107b0",func="foo", |
22656 | args=[@{name="a",value="1"],@{name="b",value="9"@}@}, | |
948d5102 | 22657 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, |
922fbb7b | 22658 | gdb-result-var="$1",return-value="0" |
594fe323 | 22659 | (gdb) |
922fbb7b AC |
22660 | @end smallexample |
22661 | ||
22662 | ||
22663 | @subheading The @code{-exec-interrupt} Command | |
22664 | @findex -exec-interrupt | |
22665 | ||
22666 | @subsubheading Synopsis | |
22667 | ||
22668 | @smallexample | |
c3b108f7 | 22669 | -exec-interrupt [--all|--thread-group N] |
922fbb7b AC |
22670 | @end smallexample |
22671 | ||
ef21caaf NR |
22672 | Interrupts the background execution of the target. Note how the token |
22673 | associated with the stop message is the one for the execution command | |
22674 | that has been interrupted. The token for the interrupt itself only | |
22675 | appears in the @samp{^done} output. If the user is trying to | |
922fbb7b AC |
22676 | interrupt a non-running program, an error message will be printed. |
22677 | ||
c3b108f7 VP |
22678 | Note that when asynchronous execution is enabled, this command is |
22679 | asynchronous just like other execution commands. That is, first the | |
22680 | @samp{^done} response will be printed, and the target stop will be | |
22681 | reported after that using the @samp{*stopped} notification. | |
22682 | ||
22683 | In non-stop mode, only the context thread is interrupted by default. | |
22684 | All threads will be interrupted if the @samp{--all} option is | |
22685 | specified. If the @samp{--thread-group} option is specified, all | |
22686 | threads in that group will be interrupted. | |
22687 | ||
922fbb7b AC |
22688 | @subsubheading @value{GDBN} Command |
22689 | ||
22690 | The corresponding @value{GDBN} command is @samp{interrupt}. | |
22691 | ||
22692 | @subsubheading Example | |
22693 | ||
22694 | @smallexample | |
594fe323 | 22695 | (gdb) |
922fbb7b AC |
22696 | 111-exec-continue |
22697 | 111^running | |
22698 | ||
594fe323 | 22699 | (gdb) |
922fbb7b AC |
22700 | 222-exec-interrupt |
22701 | 222^done | |
594fe323 | 22702 | (gdb) |
922fbb7b | 22703 | 111*stopped,signal-name="SIGINT",signal-meaning="Interrupt", |
76ff342d | 22704 | frame=@{addr="0x00010140",func="foo",args=[],file="try.c", |
948d5102 | 22705 | fullname="/home/foo/bar/try.c",line="13"@} |
594fe323 | 22706 | (gdb) |
922fbb7b | 22707 | |
594fe323 | 22708 | (gdb) |
922fbb7b AC |
22709 | -exec-interrupt |
22710 | ^error,msg="mi_cmd_exec_interrupt: Inferior not executing." | |
594fe323 | 22711 | (gdb) |
922fbb7b AC |
22712 | @end smallexample |
22713 | ||
83eba9b7 VP |
22714 | @subheading The @code{-exec-jump} Command |
22715 | @findex -exec-jump | |
22716 | ||
22717 | @subsubheading Synopsis | |
22718 | ||
22719 | @smallexample | |
22720 | -exec-jump @var{location} | |
22721 | @end smallexample | |
22722 | ||
22723 | Resumes execution of the inferior program at the location specified by | |
22724 | parameter. @xref{Specify Location}, for a description of the | |
22725 | different forms of @var{location}. | |
22726 | ||
22727 | @subsubheading @value{GDBN} Command | |
22728 | ||
22729 | The corresponding @value{GDBN} command is @samp{jump}. | |
22730 | ||
22731 | @subsubheading Example | |
22732 | ||
22733 | @smallexample | |
22734 | -exec-jump foo.c:10 | |
22735 | *running,thread-id="all" | |
22736 | ^running | |
22737 | @end smallexample | |
22738 | ||
922fbb7b AC |
22739 | |
22740 | @subheading The @code{-exec-next} Command | |
22741 | @findex -exec-next | |
22742 | ||
22743 | @subsubheading Synopsis | |
22744 | ||
22745 | @smallexample | |
22746 | -exec-next | |
22747 | @end smallexample | |
22748 | ||
ef21caaf NR |
22749 | Resumes execution of the inferior program, stopping when the beginning |
22750 | of the next source line is reached. | |
922fbb7b AC |
22751 | |
22752 | @subsubheading @value{GDBN} Command | |
22753 | ||
22754 | The corresponding @value{GDBN} command is @samp{next}. | |
22755 | ||
22756 | @subsubheading Example | |
22757 | ||
22758 | @smallexample | |
22759 | -exec-next | |
22760 | ^running | |
594fe323 | 22761 | (gdb) |
922fbb7b | 22762 | *stopped,reason="end-stepping-range",line="8",file="hello.c" |
594fe323 | 22763 | (gdb) |
922fbb7b AC |
22764 | @end smallexample |
22765 | ||
22766 | ||
22767 | @subheading The @code{-exec-next-instruction} Command | |
22768 | @findex -exec-next-instruction | |
22769 | ||
22770 | @subsubheading Synopsis | |
22771 | ||
22772 | @smallexample | |
22773 | -exec-next-instruction | |
22774 | @end smallexample | |
22775 | ||
ef21caaf NR |
22776 | Executes one machine instruction. If the instruction is a function |
22777 | call, continues until the function returns. If the program stops at an | |
22778 | instruction in the middle of a source line, the address will be | |
22779 | printed as well. | |
922fbb7b AC |
22780 | |
22781 | @subsubheading @value{GDBN} Command | |
22782 | ||
22783 | The corresponding @value{GDBN} command is @samp{nexti}. | |
22784 | ||
22785 | @subsubheading Example | |
22786 | ||
22787 | @smallexample | |
594fe323 | 22788 | (gdb) |
922fbb7b AC |
22789 | -exec-next-instruction |
22790 | ^running | |
22791 | ||
594fe323 | 22792 | (gdb) |
922fbb7b AC |
22793 | *stopped,reason="end-stepping-range", |
22794 | addr="0x000100d4",line="5",file="hello.c" | |
594fe323 | 22795 | (gdb) |
922fbb7b AC |
22796 | @end smallexample |
22797 | ||
22798 | ||
22799 | @subheading The @code{-exec-return} Command | |
22800 | @findex -exec-return | |
22801 | ||
22802 | @subsubheading Synopsis | |
22803 | ||
22804 | @smallexample | |
22805 | -exec-return | |
22806 | @end smallexample | |
22807 | ||
22808 | Makes current function return immediately. Doesn't execute the inferior. | |
22809 | Displays the new current frame. | |
22810 | ||
22811 | @subsubheading @value{GDBN} Command | |
22812 | ||
22813 | The corresponding @value{GDBN} command is @samp{return}. | |
22814 | ||
22815 | @subsubheading Example | |
22816 | ||
22817 | @smallexample | |
594fe323 | 22818 | (gdb) |
922fbb7b AC |
22819 | 200-break-insert callee4 |
22820 | 200^done,bkpt=@{number="1",addr="0x00010734", | |
22821 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"@} | |
594fe323 | 22822 | (gdb) |
922fbb7b AC |
22823 | 000-exec-run |
22824 | 000^running | |
594fe323 | 22825 | (gdb) |
a47ec5fe | 22826 | 000*stopped,reason="breakpoint-hit",disp="keep",bkptno="1", |
922fbb7b | 22827 | frame=@{func="callee4",args=[], |
76ff342d DJ |
22828 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22829 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@} | |
594fe323 | 22830 | (gdb) |
922fbb7b AC |
22831 | 205-break-delete |
22832 | 205^done | |
594fe323 | 22833 | (gdb) |
922fbb7b AC |
22834 | 111-exec-return |
22835 | 111^done,frame=@{level="0",func="callee3", | |
22836 | args=[@{name="strarg", | |
22837 | value="0x11940 \"A string argument.\""@}], | |
76ff342d DJ |
22838 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", |
22839 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@} | |
594fe323 | 22840 | (gdb) |
922fbb7b AC |
22841 | @end smallexample |
22842 | ||
22843 | ||
22844 | @subheading The @code{-exec-run} Command | |
22845 | @findex -exec-run | |
22846 | ||
22847 | @subsubheading Synopsis | |
22848 | ||
22849 | @smallexample | |
22850 | -exec-run | |
22851 | @end smallexample | |
22852 | ||
ef21caaf NR |
22853 | Starts execution of the inferior from the beginning. The inferior |
22854 | executes until either a breakpoint is encountered or the program | |
22855 | exits. In the latter case the output will include an exit code, if | |
22856 | the program has exited exceptionally. | |
922fbb7b AC |
22857 | |
22858 | @subsubheading @value{GDBN} Command | |
22859 | ||
22860 | The corresponding @value{GDBN} command is @samp{run}. | |
22861 | ||
ef21caaf | 22862 | @subsubheading Examples |
922fbb7b AC |
22863 | |
22864 | @smallexample | |
594fe323 | 22865 | (gdb) |
922fbb7b AC |
22866 | -break-insert main |
22867 | ^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c",line="4"@} | |
594fe323 | 22868 | (gdb) |
922fbb7b AC |
22869 | -exec-run |
22870 | ^running | |
594fe323 | 22871 | (gdb) |
a47ec5fe | 22872 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1", |
76ff342d | 22873 | frame=@{func="main",args=[],file="recursive2.c", |
948d5102 | 22874 | fullname="/home/foo/bar/recursive2.c",line="4"@} |
594fe323 | 22875 | (gdb) |
922fbb7b AC |
22876 | @end smallexample |
22877 | ||
ef21caaf NR |
22878 | @noindent |
22879 | Program exited normally: | |
22880 | ||
22881 | @smallexample | |
594fe323 | 22882 | (gdb) |
ef21caaf NR |
22883 | -exec-run |
22884 | ^running | |
594fe323 | 22885 | (gdb) |
ef21caaf NR |
22886 | x = 55 |
22887 | *stopped,reason="exited-normally" | |
594fe323 | 22888 | (gdb) |
ef21caaf NR |
22889 | @end smallexample |
22890 | ||
22891 | @noindent | |
22892 | Program exited exceptionally: | |
22893 | ||
22894 | @smallexample | |
594fe323 | 22895 | (gdb) |
ef21caaf NR |
22896 | -exec-run |
22897 | ^running | |
594fe323 | 22898 | (gdb) |
ef21caaf NR |
22899 | x = 55 |
22900 | *stopped,reason="exited",exit-code="01" | |
594fe323 | 22901 | (gdb) |
ef21caaf NR |
22902 | @end smallexample |
22903 | ||
22904 | Another way the program can terminate is if it receives a signal such as | |
22905 | @code{SIGINT}. In this case, @sc{gdb/mi} displays this: | |
22906 | ||
22907 | @smallexample | |
594fe323 | 22908 | (gdb) |
ef21caaf NR |
22909 | *stopped,reason="exited-signalled",signal-name="SIGINT", |
22910 | signal-meaning="Interrupt" | |
22911 | @end smallexample | |
22912 | ||
922fbb7b | 22913 | |
a2c02241 NR |
22914 | @c @subheading -exec-signal |
22915 | ||
22916 | ||
22917 | @subheading The @code{-exec-step} Command | |
22918 | @findex -exec-step | |
922fbb7b AC |
22919 | |
22920 | @subsubheading Synopsis | |
22921 | ||
22922 | @smallexample | |
a2c02241 | 22923 | -exec-step |
922fbb7b AC |
22924 | @end smallexample |
22925 | ||
a2c02241 NR |
22926 | Resumes execution of the inferior program, stopping when the beginning |
22927 | of the next source line is reached, if the next source line is not a | |
22928 | function call. If it is, stop at the first instruction of the called | |
22929 | function. | |
922fbb7b AC |
22930 | |
22931 | @subsubheading @value{GDBN} Command | |
22932 | ||
a2c02241 | 22933 | The corresponding @value{GDBN} command is @samp{step}. |
922fbb7b AC |
22934 | |
22935 | @subsubheading Example | |
22936 | ||
22937 | Stepping into a function: | |
22938 | ||
22939 | @smallexample | |
22940 | -exec-step | |
22941 | ^running | |
594fe323 | 22942 | (gdb) |
922fbb7b AC |
22943 | *stopped,reason="end-stepping-range", |
22944 | frame=@{func="foo",args=[@{name="a",value="10"@}, | |
76ff342d | 22945 | @{name="b",value="0"@}],file="recursive2.c", |
948d5102 | 22946 | fullname="/home/foo/bar/recursive2.c",line="11"@} |
594fe323 | 22947 | (gdb) |
922fbb7b AC |
22948 | @end smallexample |
22949 | ||
22950 | Regular stepping: | |
22951 | ||
22952 | @smallexample | |
22953 | -exec-step | |
22954 | ^running | |
594fe323 | 22955 | (gdb) |
922fbb7b | 22956 | *stopped,reason="end-stepping-range",line="14",file="recursive2.c" |
594fe323 | 22957 | (gdb) |
922fbb7b AC |
22958 | @end smallexample |
22959 | ||
22960 | ||
22961 | @subheading The @code{-exec-step-instruction} Command | |
22962 | @findex -exec-step-instruction | |
22963 | ||
22964 | @subsubheading Synopsis | |
22965 | ||
22966 | @smallexample | |
22967 | -exec-step-instruction | |
22968 | @end smallexample | |
22969 | ||
ef21caaf NR |
22970 | Resumes the inferior which executes one machine instruction. The |
22971 | output, once @value{GDBN} has stopped, will vary depending on whether | |
22972 | we have stopped in the middle of a source line or not. In the former | |
22973 | case, the address at which the program stopped will be printed as | |
922fbb7b AC |
22974 | well. |
22975 | ||
22976 | @subsubheading @value{GDBN} Command | |
22977 | ||
22978 | The corresponding @value{GDBN} command is @samp{stepi}. | |
22979 | ||
22980 | @subsubheading Example | |
22981 | ||
22982 | @smallexample | |
594fe323 | 22983 | (gdb) |
922fbb7b AC |
22984 | -exec-step-instruction |
22985 | ^running | |
22986 | ||
594fe323 | 22987 | (gdb) |
922fbb7b | 22988 | *stopped,reason="end-stepping-range", |
76ff342d | 22989 | frame=@{func="foo",args=[],file="try.c", |
948d5102 | 22990 | fullname="/home/foo/bar/try.c",line="10"@} |
594fe323 | 22991 | (gdb) |
922fbb7b AC |
22992 | -exec-step-instruction |
22993 | ^running | |
22994 | ||
594fe323 | 22995 | (gdb) |
922fbb7b | 22996 | *stopped,reason="end-stepping-range", |
76ff342d | 22997 | frame=@{addr="0x000100f4",func="foo",args=[],file="try.c", |
948d5102 | 22998 | fullname="/home/foo/bar/try.c",line="10"@} |
594fe323 | 22999 | (gdb) |
922fbb7b AC |
23000 | @end smallexample |
23001 | ||
23002 | ||
23003 | @subheading The @code{-exec-until} Command | |
23004 | @findex -exec-until | |
23005 | ||
23006 | @subsubheading Synopsis | |
23007 | ||
23008 | @smallexample | |
23009 | -exec-until [ @var{location} ] | |
23010 | @end smallexample | |
23011 | ||
ef21caaf NR |
23012 | Executes the inferior until the @var{location} specified in the |
23013 | argument is reached. If there is no argument, the inferior executes | |
23014 | until a source line greater than the current one is reached. The | |
23015 | reason for stopping in this case will be @samp{location-reached}. | |
922fbb7b AC |
23016 | |
23017 | @subsubheading @value{GDBN} Command | |
23018 | ||
23019 | The corresponding @value{GDBN} command is @samp{until}. | |
23020 | ||
23021 | @subsubheading Example | |
23022 | ||
23023 | @smallexample | |
594fe323 | 23024 | (gdb) |
922fbb7b AC |
23025 | -exec-until recursive2.c:6 |
23026 | ^running | |
594fe323 | 23027 | (gdb) |
922fbb7b AC |
23028 | x = 55 |
23029 | *stopped,reason="location-reached",frame=@{func="main",args=[], | |
948d5102 | 23030 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="6"@} |
594fe323 | 23031 | (gdb) |
922fbb7b AC |
23032 | @end smallexample |
23033 | ||
23034 | @ignore | |
23035 | @subheading -file-clear | |
23036 | Is this going away???? | |
23037 | @end ignore | |
23038 | ||
351ff01a | 23039 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
a2c02241 NR |
23040 | @node GDB/MI Stack Manipulation |
23041 | @section @sc{gdb/mi} Stack Manipulation Commands | |
351ff01a | 23042 | |
922fbb7b | 23043 | |
a2c02241 NR |
23044 | @subheading The @code{-stack-info-frame} Command |
23045 | @findex -stack-info-frame | |
922fbb7b AC |
23046 | |
23047 | @subsubheading Synopsis | |
23048 | ||
23049 | @smallexample | |
a2c02241 | 23050 | -stack-info-frame |
922fbb7b AC |
23051 | @end smallexample |
23052 | ||
a2c02241 | 23053 | Get info on the selected frame. |
922fbb7b AC |
23054 | |
23055 | @subsubheading @value{GDBN} Command | |
23056 | ||
a2c02241 NR |
23057 | The corresponding @value{GDBN} command is @samp{info frame} or @samp{frame} |
23058 | (without arguments). | |
922fbb7b AC |
23059 | |
23060 | @subsubheading Example | |
23061 | ||
23062 | @smallexample | |
594fe323 | 23063 | (gdb) |
a2c02241 NR |
23064 | -stack-info-frame |
23065 | ^done,frame=@{level="1",addr="0x0001076c",func="callee3", | |
23066 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23067 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@} | |
594fe323 | 23068 | (gdb) |
922fbb7b AC |
23069 | @end smallexample |
23070 | ||
a2c02241 NR |
23071 | @subheading The @code{-stack-info-depth} Command |
23072 | @findex -stack-info-depth | |
922fbb7b AC |
23073 | |
23074 | @subsubheading Synopsis | |
23075 | ||
23076 | @smallexample | |
a2c02241 | 23077 | -stack-info-depth [ @var{max-depth} ] |
922fbb7b AC |
23078 | @end smallexample |
23079 | ||
a2c02241 NR |
23080 | Return the depth of the stack. If the integer argument @var{max-depth} |
23081 | is specified, do not count beyond @var{max-depth} frames. | |
922fbb7b AC |
23082 | |
23083 | @subsubheading @value{GDBN} Command | |
23084 | ||
a2c02241 | 23085 | There's no equivalent @value{GDBN} command. |
922fbb7b AC |
23086 | |
23087 | @subsubheading Example | |
23088 | ||
a2c02241 NR |
23089 | For a stack with frame levels 0 through 11: |
23090 | ||
922fbb7b | 23091 | @smallexample |
594fe323 | 23092 | (gdb) |
a2c02241 NR |
23093 | -stack-info-depth |
23094 | ^done,depth="12" | |
594fe323 | 23095 | (gdb) |
a2c02241 NR |
23096 | -stack-info-depth 4 |
23097 | ^done,depth="4" | |
594fe323 | 23098 | (gdb) |
a2c02241 NR |
23099 | -stack-info-depth 12 |
23100 | ^done,depth="12" | |
594fe323 | 23101 | (gdb) |
a2c02241 NR |
23102 | -stack-info-depth 11 |
23103 | ^done,depth="11" | |
594fe323 | 23104 | (gdb) |
a2c02241 NR |
23105 | -stack-info-depth 13 |
23106 | ^done,depth="12" | |
594fe323 | 23107 | (gdb) |
922fbb7b AC |
23108 | @end smallexample |
23109 | ||
a2c02241 NR |
23110 | @subheading The @code{-stack-list-arguments} Command |
23111 | @findex -stack-list-arguments | |
922fbb7b AC |
23112 | |
23113 | @subsubheading Synopsis | |
23114 | ||
23115 | @smallexample | |
a2c02241 NR |
23116 | -stack-list-arguments @var{show-values} |
23117 | [ @var{low-frame} @var{high-frame} ] | |
922fbb7b AC |
23118 | @end smallexample |
23119 | ||
a2c02241 NR |
23120 | Display a list of the arguments for the frames between @var{low-frame} |
23121 | and @var{high-frame} (inclusive). If @var{low-frame} and | |
2f1acb09 VP |
23122 | @var{high-frame} are not provided, list the arguments for the whole |
23123 | call stack. If the two arguments are equal, show the single frame | |
23124 | at the corresponding level. It is an error if @var{low-frame} is | |
23125 | larger than the actual number of frames. On the other hand, | |
23126 | @var{high-frame} may be larger than the actual number of frames, in | |
23127 | which case only existing frames will be returned. | |
a2c02241 NR |
23128 | |
23129 | The @var{show-values} argument must have a value of 0 or 1. A value of | |
23130 | 0 means that only the names of the arguments are listed, a value of 1 | |
23131 | means that both names and values of the arguments are printed. | |
922fbb7b | 23132 | |
b3372f91 VP |
23133 | Use of this command to obtain arguments in a single frame is |
23134 | deprecated in favor of the @samp{-stack-list-variables} command. | |
23135 | ||
922fbb7b AC |
23136 | @subsubheading @value{GDBN} Command |
23137 | ||
a2c02241 NR |
23138 | @value{GDBN} does not have an equivalent command. @code{gdbtk} has a |
23139 | @samp{gdb_get_args} command which partially overlaps with the | |
23140 | functionality of @samp{-stack-list-arguments}. | |
922fbb7b AC |
23141 | |
23142 | @subsubheading Example | |
922fbb7b | 23143 | |
a2c02241 | 23144 | @smallexample |
594fe323 | 23145 | (gdb) |
a2c02241 NR |
23146 | -stack-list-frames |
23147 | ^done, | |
23148 | stack=[ | |
23149 | frame=@{level="0",addr="0x00010734",func="callee4", | |
23150 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23151 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@}, | |
23152 | frame=@{level="1",addr="0x0001076c",func="callee3", | |
23153 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23154 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@}, | |
23155 | frame=@{level="2",addr="0x0001078c",func="callee2", | |
23156 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23157 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="22"@}, | |
23158 | frame=@{level="3",addr="0x000107b4",func="callee1", | |
23159 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23160 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="27"@}, | |
23161 | frame=@{level="4",addr="0x000107e0",func="main", | |
23162 | file="../../../devo/gdb/testsuite/gdb.mi/basics.c", | |
23163 | fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="32"@}] | |
594fe323 | 23164 | (gdb) |
a2c02241 NR |
23165 | -stack-list-arguments 0 |
23166 | ^done, | |
23167 | stack-args=[ | |
23168 | frame=@{level="0",args=[]@}, | |
23169 | frame=@{level="1",args=[name="strarg"]@}, | |
23170 | frame=@{level="2",args=[name="intarg",name="strarg"]@}, | |
23171 | frame=@{level="3",args=[name="intarg",name="strarg",name="fltarg"]@}, | |
23172 | frame=@{level="4",args=[]@}] | |
594fe323 | 23173 | (gdb) |
a2c02241 NR |
23174 | -stack-list-arguments 1 |
23175 | ^done, | |
23176 | stack-args=[ | |
23177 | frame=@{level="0",args=[]@}, | |
23178 | frame=@{level="1", | |
23179 | args=[@{name="strarg",value="0x11940 \"A string argument.\""@}]@}, | |
23180 | frame=@{level="2",args=[ | |
23181 | @{name="intarg",value="2"@}, | |
23182 | @{name="strarg",value="0x11940 \"A string argument.\""@}]@}, | |
23183 | @{frame=@{level="3",args=[ | |
23184 | @{name="intarg",value="2"@}, | |
23185 | @{name="strarg",value="0x11940 \"A string argument.\""@}, | |
23186 | @{name="fltarg",value="3.5"@}]@}, | |
23187 | frame=@{level="4",args=[]@}] | |
594fe323 | 23188 | (gdb) |
a2c02241 NR |
23189 | -stack-list-arguments 0 2 2 |
23190 | ^done,stack-args=[frame=@{level="2",args=[name="intarg",name="strarg"]@}] | |
594fe323 | 23191 | (gdb) |
a2c02241 NR |
23192 | -stack-list-arguments 1 2 2 |
23193 | ^done,stack-args=[frame=@{level="2", | |
23194 | args=[@{name="intarg",value="2"@}, | |
23195 | @{name="strarg",value="0x11940 \"A string argument.\""@}]@}] | |
594fe323 | 23196 | (gdb) |
a2c02241 NR |
23197 | @end smallexample |
23198 | ||
23199 | @c @subheading -stack-list-exception-handlers | |
922fbb7b | 23200 | |
a2c02241 NR |
23201 | |
23202 | @subheading The @code{-stack-list-frames} Command | |
23203 | @findex -stack-list-frames | |
1abaf70c BR |
23204 | |
23205 | @subsubheading Synopsis | |
23206 | ||
23207 | @smallexample | |
a2c02241 | 23208 | -stack-list-frames [ @var{low-frame} @var{high-frame} ] |
1abaf70c BR |
23209 | @end smallexample |
23210 | ||
a2c02241 NR |
23211 | List the frames currently on the stack. For each frame it displays the |
23212 | following info: | |
23213 | ||
23214 | @table @samp | |
23215 | @item @var{level} | |
d3e8051b | 23216 | The frame number, 0 being the topmost frame, i.e., the innermost function. |
a2c02241 NR |
23217 | @item @var{addr} |
23218 | The @code{$pc} value for that frame. | |
23219 | @item @var{func} | |
23220 | Function name. | |
23221 | @item @var{file} | |
23222 | File name of the source file where the function lives. | |
23223 | @item @var{line} | |
23224 | Line number corresponding to the @code{$pc}. | |
23225 | @end table | |
23226 | ||
23227 | If invoked without arguments, this command prints a backtrace for the | |
23228 | whole stack. If given two integer arguments, it shows the frames whose | |
23229 | levels are between the two arguments (inclusive). If the two arguments | |
2ab1eb7a VP |
23230 | are equal, it shows the single frame at the corresponding level. It is |
23231 | an error if @var{low-frame} is larger than the actual number of | |
a5451f4e | 23232 | frames. On the other hand, @var{high-frame} may be larger than the |
2ab1eb7a | 23233 | actual number of frames, in which case only existing frames will be returned. |
1abaf70c BR |
23234 | |
23235 | @subsubheading @value{GDBN} Command | |
23236 | ||
a2c02241 | 23237 | The corresponding @value{GDBN} commands are @samp{backtrace} and @samp{where}. |
1abaf70c BR |
23238 | |
23239 | @subsubheading Example | |
23240 | ||
a2c02241 NR |
23241 | Full stack backtrace: |
23242 | ||
1abaf70c | 23243 | @smallexample |
594fe323 | 23244 | (gdb) |
a2c02241 NR |
23245 | -stack-list-frames |
23246 | ^done,stack= | |
23247 | [frame=@{level="0",addr="0x0001076c",func="foo", | |
23248 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="11"@}, | |
23249 | frame=@{level="1",addr="0x000107a4",func="foo", | |
23250 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23251 | frame=@{level="2",addr="0x000107a4",func="foo", | |
23252 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23253 | frame=@{level="3",addr="0x000107a4",func="foo", | |
23254 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23255 | frame=@{level="4",addr="0x000107a4",func="foo", | |
23256 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23257 | frame=@{level="5",addr="0x000107a4",func="foo", | |
23258 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23259 | frame=@{level="6",addr="0x000107a4",func="foo", | |
23260 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23261 | frame=@{level="7",addr="0x000107a4",func="foo", | |
23262 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23263 | frame=@{level="8",addr="0x000107a4",func="foo", | |
23264 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23265 | frame=@{level="9",addr="0x000107a4",func="foo", | |
23266 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23267 | frame=@{level="10",addr="0x000107a4",func="foo", | |
23268 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23269 | frame=@{level="11",addr="0x00010738",func="main", | |
23270 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="4"@}] | |
594fe323 | 23271 | (gdb) |
1abaf70c BR |
23272 | @end smallexample |
23273 | ||
a2c02241 | 23274 | Show frames between @var{low_frame} and @var{high_frame}: |
1abaf70c | 23275 | |
a2c02241 | 23276 | @smallexample |
594fe323 | 23277 | (gdb) |
a2c02241 NR |
23278 | -stack-list-frames 3 5 |
23279 | ^done,stack= | |
23280 | [frame=@{level="3",addr="0x000107a4",func="foo", | |
23281 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23282 | frame=@{level="4",addr="0x000107a4",func="foo", | |
23283 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}, | |
23284 | frame=@{level="5",addr="0x000107a4",func="foo", | |
23285 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}] | |
594fe323 | 23286 | (gdb) |
a2c02241 | 23287 | @end smallexample |
922fbb7b | 23288 | |
a2c02241 | 23289 | Show a single frame: |
922fbb7b AC |
23290 | |
23291 | @smallexample | |
594fe323 | 23292 | (gdb) |
a2c02241 NR |
23293 | -stack-list-frames 3 3 |
23294 | ^done,stack= | |
23295 | [frame=@{level="3",addr="0x000107a4",func="foo", | |
23296 | file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}] | |
594fe323 | 23297 | (gdb) |
922fbb7b AC |
23298 | @end smallexample |
23299 | ||
922fbb7b | 23300 | |
a2c02241 NR |
23301 | @subheading The @code{-stack-list-locals} Command |
23302 | @findex -stack-list-locals | |
57c22c6c | 23303 | |
a2c02241 | 23304 | @subsubheading Synopsis |
922fbb7b AC |
23305 | |
23306 | @smallexample | |
a2c02241 | 23307 | -stack-list-locals @var{print-values} |
922fbb7b AC |
23308 | @end smallexample |
23309 | ||
a2c02241 NR |
23310 | Display the local variable names for the selected frame. If |
23311 | @var{print-values} is 0 or @code{--no-values}, print only the names of | |
23312 | the variables; if it is 1 or @code{--all-values}, print also their | |
23313 | values; and if it is 2 or @code{--simple-values}, print the name, | |
23314 | type and value for simple data types and the name and type for arrays, | |
23315 | structures and unions. In this last case, a frontend can immediately | |
23316 | display the value of simple data types and create variable objects for | |
d3e8051b | 23317 | other data types when the user wishes to explore their values in |
a2c02241 | 23318 | more detail. |
922fbb7b | 23319 | |
b3372f91 VP |
23320 | This command is deprecated in favor of the |
23321 | @samp{-stack-list-variables} command. | |
23322 | ||
922fbb7b AC |
23323 | @subsubheading @value{GDBN} Command |
23324 | ||
a2c02241 | 23325 | @samp{info locals} in @value{GDBN}, @samp{gdb_get_locals} in @code{gdbtk}. |
922fbb7b AC |
23326 | |
23327 | @subsubheading Example | |
922fbb7b AC |
23328 | |
23329 | @smallexample | |
594fe323 | 23330 | (gdb) |
a2c02241 NR |
23331 | -stack-list-locals 0 |
23332 | ^done,locals=[name="A",name="B",name="C"] | |
594fe323 | 23333 | (gdb) |
a2c02241 NR |
23334 | -stack-list-locals --all-values |
23335 | ^done,locals=[@{name="A",value="1"@},@{name="B",value="2"@}, | |
23336 | @{name="C",value="@{1, 2, 3@}"@}] | |
23337 | -stack-list-locals --simple-values | |
23338 | ^done,locals=[@{name="A",type="int",value="1"@}, | |
23339 | @{name="B",type="int",value="2"@},@{name="C",type="int [3]"@}] | |
594fe323 | 23340 | (gdb) |
922fbb7b AC |
23341 | @end smallexample |
23342 | ||
b3372f91 VP |
23343 | @subheading The @code{-stack-list-variables} Command |
23344 | @findex -stack-list-variables | |
23345 | ||
23346 | @subsubheading Synopsis | |
23347 | ||
23348 | @smallexample | |
23349 | -stack-list-variables @var{print-values} | |
23350 | @end smallexample | |
23351 | ||
23352 | Display the names of local variables and function arguments for the selected frame. If | |
23353 | @var{print-values} is 0 or @code{--no-values}, print only the names of | |
23354 | the variables; if it is 1 or @code{--all-values}, print also their | |
23355 | values; and if it is 2 or @code{--simple-values}, print the name, | |
23356 | type and value for simple data types and the name and type for arrays, | |
23357 | structures and unions. | |
23358 | ||
23359 | @subsubheading Example | |
23360 | ||
23361 | @smallexample | |
23362 | (gdb) | |
23363 | -stack-list-variables --thread 1 --frame 0 --all-values | |
4f412fd0 | 23364 | ^done,variables=[@{name="x",value="11"@},@{name="s",value="@{a = 1, b = 2@}"@}] |
b3372f91 VP |
23365 | (gdb) |
23366 | @end smallexample | |
23367 | ||
922fbb7b | 23368 | |
a2c02241 NR |
23369 | @subheading The @code{-stack-select-frame} Command |
23370 | @findex -stack-select-frame | |
922fbb7b AC |
23371 | |
23372 | @subsubheading Synopsis | |
23373 | ||
23374 | @smallexample | |
a2c02241 | 23375 | -stack-select-frame @var{framenum} |
922fbb7b AC |
23376 | @end smallexample |
23377 | ||
a2c02241 NR |
23378 | Change the selected frame. Select a different frame @var{framenum} on |
23379 | the stack. | |
922fbb7b | 23380 | |
c3b108f7 VP |
23381 | This command in deprecated in favor of passing the @samp{--frame} |
23382 | option to every command. | |
23383 | ||
922fbb7b AC |
23384 | @subsubheading @value{GDBN} Command |
23385 | ||
a2c02241 NR |
23386 | The corresponding @value{GDBN} commands are @samp{frame}, @samp{up}, |
23387 | @samp{down}, @samp{select-frame}, @samp{up-silent}, and @samp{down-silent}. | |
922fbb7b AC |
23388 | |
23389 | @subsubheading Example | |
23390 | ||
23391 | @smallexample | |
594fe323 | 23392 | (gdb) |
a2c02241 | 23393 | -stack-select-frame 2 |
922fbb7b | 23394 | ^done |
594fe323 | 23395 | (gdb) |
922fbb7b AC |
23396 | @end smallexample |
23397 | ||
23398 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
a2c02241 NR |
23399 | @node GDB/MI Variable Objects |
23400 | @section @sc{gdb/mi} Variable Objects | |
922fbb7b | 23401 | |
a1b5960f | 23402 | @ignore |
922fbb7b | 23403 | |
a2c02241 | 23404 | @subheading Motivation for Variable Objects in @sc{gdb/mi} |
922fbb7b | 23405 | |
a2c02241 NR |
23406 | For the implementation of a variable debugger window (locals, watched |
23407 | expressions, etc.), we are proposing the adaptation of the existing code | |
23408 | used by @code{Insight}. | |
922fbb7b | 23409 | |
a2c02241 | 23410 | The two main reasons for that are: |
922fbb7b | 23411 | |
a2c02241 NR |
23412 | @enumerate 1 |
23413 | @item | |
23414 | It has been proven in practice (it is already on its second generation). | |
922fbb7b | 23415 | |
a2c02241 NR |
23416 | @item |
23417 | It will shorten development time (needless to say how important it is | |
23418 | now). | |
23419 | @end enumerate | |
922fbb7b | 23420 | |
a2c02241 NR |
23421 | The original interface was designed to be used by Tcl code, so it was |
23422 | slightly changed so it could be used through @sc{gdb/mi}. This section | |
23423 | describes the @sc{gdb/mi} operations that will be available and gives some | |
23424 | hints about their use. | |
922fbb7b | 23425 | |
a2c02241 NR |
23426 | @emph{Note}: In addition to the set of operations described here, we |
23427 | expect the @sc{gui} implementation of a variable window to require, at | |
23428 | least, the following operations: | |
922fbb7b | 23429 | |
a2c02241 NR |
23430 | @itemize @bullet |
23431 | @item @code{-gdb-show} @code{output-radix} | |
23432 | @item @code{-stack-list-arguments} | |
23433 | @item @code{-stack-list-locals} | |
23434 | @item @code{-stack-select-frame} | |
23435 | @end itemize | |
922fbb7b | 23436 | |
a1b5960f VP |
23437 | @end ignore |
23438 | ||
c8b2f53c | 23439 | @subheading Introduction to Variable Objects |
922fbb7b | 23440 | |
a2c02241 | 23441 | @cindex variable objects in @sc{gdb/mi} |
c8b2f53c VP |
23442 | |
23443 | Variable objects are "object-oriented" MI interface for examining and | |
23444 | changing values of expressions. Unlike some other MI interfaces that | |
23445 | work with expressions, variable objects are specifically designed for | |
23446 | simple and efficient presentation in the frontend. A variable object | |
23447 | is identified by string name. When a variable object is created, the | |
23448 | frontend specifies the expression for that variable object. The | |
23449 | expression can be a simple variable, or it can be an arbitrary complex | |
23450 | expression, and can even involve CPU registers. After creating a | |
23451 | variable object, the frontend can invoke other variable object | |
23452 | operations---for example to obtain or change the value of a variable | |
23453 | object, or to change display format. | |
23454 | ||
23455 | Variable objects have hierarchical tree structure. Any variable object | |
23456 | that corresponds to a composite type, such as structure in C, has | |
23457 | a number of child variable objects, for example corresponding to each | |
23458 | element of a structure. A child variable object can itself have | |
23459 | children, recursively. Recursion ends when we reach | |
25d5ea92 VP |
23460 | leaf variable objects, which always have built-in types. Child variable |
23461 | objects are created only by explicit request, so if a frontend | |
23462 | is not interested in the children of a particular variable object, no | |
23463 | child will be created. | |
c8b2f53c VP |
23464 | |
23465 | For a leaf variable object it is possible to obtain its value as a | |
23466 | string, or set the value from a string. String value can be also | |
23467 | obtained for a non-leaf variable object, but it's generally a string | |
23468 | that only indicates the type of the object, and does not list its | |
23469 | contents. Assignment to a non-leaf variable object is not allowed. | |
23470 | ||
23471 | A frontend does not need to read the values of all variable objects each time | |
23472 | the program stops. Instead, MI provides an update command that lists all | |
23473 | variable objects whose values has changed since the last update | |
23474 | operation. This considerably reduces the amount of data that must | |
25d5ea92 VP |
23475 | be transferred to the frontend. As noted above, children variable |
23476 | objects are created on demand, and only leaf variable objects have a | |
23477 | real value. As result, gdb will read target memory only for leaf | |
23478 | variables that frontend has created. | |
23479 | ||
23480 | The automatic update is not always desirable. For example, a frontend | |
23481 | might want to keep a value of some expression for future reference, | |
23482 | and never update it. For another example, fetching memory is | |
23483 | relatively slow for embedded targets, so a frontend might want | |
23484 | to disable automatic update for the variables that are either not | |
23485 | visible on the screen, or ``closed''. This is possible using so | |
23486 | called ``frozen variable objects''. Such variable objects are never | |
23487 | implicitly updated. | |
922fbb7b | 23488 | |
c3b108f7 VP |
23489 | Variable objects can be either @dfn{fixed} or @dfn{floating}. For the |
23490 | fixed variable object, the expression is parsed when the variable | |
23491 | object is created, including associating identifiers to specific | |
23492 | variables. The meaning of expression never changes. For a floating | |
23493 | variable object the values of variables whose names appear in the | |
23494 | expressions are re-evaluated every time in the context of the current | |
23495 | frame. Consider this example: | |
23496 | ||
23497 | @smallexample | |
23498 | void do_work(...) | |
23499 | @{ | |
23500 | struct work_state state; | |
23501 | ||
23502 | if (...) | |
23503 | do_work(...); | |
23504 | @} | |
23505 | @end smallexample | |
23506 | ||
23507 | If a fixed variable object for the @code{state} variable is created in | |
23508 | this function, and we enter the recursive call, the the variable | |
23509 | object will report the value of @code{state} in the top-level | |
23510 | @code{do_work} invocation. On the other hand, a floating variable | |
23511 | object will report the value of @code{state} in the current frame. | |
23512 | ||
23513 | If an expression specified when creating a fixed variable object | |
23514 | refers to a local variable, the variable object becomes bound to the | |
23515 | thread and frame in which the variable object is created. When such | |
23516 | variable object is updated, @value{GDBN} makes sure that the | |
23517 | thread/frame combination the variable object is bound to still exists, | |
23518 | and re-evaluates the variable object in context of that thread/frame. | |
23519 | ||
a2c02241 NR |
23520 | The following is the complete set of @sc{gdb/mi} operations defined to |
23521 | access this functionality: | |
922fbb7b | 23522 | |
a2c02241 NR |
23523 | @multitable @columnfractions .4 .6 |
23524 | @item @strong{Operation} | |
23525 | @tab @strong{Description} | |
922fbb7b | 23526 | |
0cc7d26f TT |
23527 | @item @code{-enable-pretty-printing} |
23528 | @tab enable Python-based pretty-printing | |
a2c02241 NR |
23529 | @item @code{-var-create} |
23530 | @tab create a variable object | |
23531 | @item @code{-var-delete} | |
22d8a470 | 23532 | @tab delete the variable object and/or its children |
a2c02241 NR |
23533 | @item @code{-var-set-format} |
23534 | @tab set the display format of this variable | |
23535 | @item @code{-var-show-format} | |
23536 | @tab show the display format of this variable | |
23537 | @item @code{-var-info-num-children} | |
23538 | @tab tells how many children this object has | |
23539 | @item @code{-var-list-children} | |
23540 | @tab return a list of the object's children | |
23541 | @item @code{-var-info-type} | |
23542 | @tab show the type of this variable object | |
23543 | @item @code{-var-info-expression} | |
02142340 VP |
23544 | @tab print parent-relative expression that this variable object represents |
23545 | @item @code{-var-info-path-expression} | |
23546 | @tab print full expression that this variable object represents | |
a2c02241 NR |
23547 | @item @code{-var-show-attributes} |
23548 | @tab is this variable editable? does it exist here? | |
23549 | @item @code{-var-evaluate-expression} | |
23550 | @tab get the value of this variable | |
23551 | @item @code{-var-assign} | |
23552 | @tab set the value of this variable | |
23553 | @item @code{-var-update} | |
23554 | @tab update the variable and its children | |
25d5ea92 VP |
23555 | @item @code{-var-set-frozen} |
23556 | @tab set frozeness attribute | |
0cc7d26f TT |
23557 | @item @code{-var-set-update-range} |
23558 | @tab set range of children to display on update | |
a2c02241 | 23559 | @end multitable |
922fbb7b | 23560 | |
a2c02241 NR |
23561 | In the next subsection we describe each operation in detail and suggest |
23562 | how it can be used. | |
922fbb7b | 23563 | |
a2c02241 | 23564 | @subheading Description And Use of Operations on Variable Objects |
922fbb7b | 23565 | |
0cc7d26f TT |
23566 | @subheading The @code{-enable-pretty-printing} Command |
23567 | @findex -enable-pretty-printing | |
23568 | ||
23569 | @smallexample | |
23570 | -enable-pretty-printing | |
23571 | @end smallexample | |
23572 | ||
23573 | @value{GDBN} allows Python-based visualizers to affect the output of the | |
23574 | MI variable object commands. However, because there was no way to | |
23575 | implement this in a fully backward-compatible way, a front end must | |
23576 | request that this functionality be enabled. | |
23577 | ||
23578 | Once enabled, this feature cannot be disabled. | |
23579 | ||
23580 | Note that if Python support has not been compiled into @value{GDBN}, | |
23581 | this command will still succeed (and do nothing). | |
23582 | ||
f43030c4 TT |
23583 | This feature is currently (as of @value{GDBN} 7.0) experimental, and |
23584 | may work differently in future versions of @value{GDBN}. | |
23585 | ||
a2c02241 NR |
23586 | @subheading The @code{-var-create} Command |
23587 | @findex -var-create | |
ef21caaf | 23588 | |
a2c02241 | 23589 | @subsubheading Synopsis |
ef21caaf | 23590 | |
a2c02241 NR |
23591 | @smallexample |
23592 | -var-create @{@var{name} | "-"@} | |
c3b108f7 | 23593 | @{@var{frame-addr} | "*" | "@@"@} @var{expression} |
a2c02241 NR |
23594 | @end smallexample |
23595 | ||
23596 | This operation creates a variable object, which allows the monitoring of | |
23597 | a variable, the result of an expression, a memory cell or a CPU | |
23598 | register. | |
ef21caaf | 23599 | |
a2c02241 NR |
23600 | The @var{name} parameter is the string by which the object can be |
23601 | referenced. It must be unique. If @samp{-} is specified, the varobj | |
23602 | system will generate a string ``varNNNNNN'' automatically. It will be | |
c3b108f7 | 23603 | unique provided that one does not specify @var{name} of that format. |
a2c02241 | 23604 | The command fails if a duplicate name is found. |
ef21caaf | 23605 | |
a2c02241 NR |
23606 | The frame under which the expression should be evaluated can be |
23607 | specified by @var{frame-addr}. A @samp{*} indicates that the current | |
c3b108f7 VP |
23608 | frame should be used. A @samp{@@} indicates that a floating variable |
23609 | object must be created. | |
922fbb7b | 23610 | |
a2c02241 NR |
23611 | @var{expression} is any expression valid on the current language set (must not |
23612 | begin with a @samp{*}), or one of the following: | |
922fbb7b | 23613 | |
a2c02241 NR |
23614 | @itemize @bullet |
23615 | @item | |
23616 | @samp{*@var{addr}}, where @var{addr} is the address of a memory cell | |
922fbb7b | 23617 | |
a2c02241 NR |
23618 | @item |
23619 | @samp{*@var{addr}-@var{addr}} --- a memory address range (TBD) | |
922fbb7b | 23620 | |
a2c02241 NR |
23621 | @item |
23622 | @samp{$@var{regname}} --- a CPU register name | |
23623 | @end itemize | |
922fbb7b | 23624 | |
0cc7d26f TT |
23625 | @cindex dynamic varobj |
23626 | A varobj's contents may be provided by a Python-based pretty-printer. In this | |
23627 | case the varobj is known as a @dfn{dynamic varobj}. Dynamic varobjs | |
23628 | have slightly different semantics in some cases. If the | |
23629 | @code{-enable-pretty-printing} command is not sent, then @value{GDBN} | |
23630 | will never create a dynamic varobj. This ensures backward | |
23631 | compatibility for existing clients. | |
23632 | ||
a2c02241 | 23633 | @subsubheading Result |
922fbb7b | 23634 | |
0cc7d26f TT |
23635 | This operation returns attributes of the newly-created varobj. These |
23636 | are: | |
23637 | ||
23638 | @table @samp | |
23639 | @item name | |
23640 | The name of the varobj. | |
23641 | ||
23642 | @item numchild | |
23643 | The number of children of the varobj. This number is not necessarily | |
23644 | reliable for a dynamic varobj. Instead, you must examine the | |
23645 | @samp{has_more} attribute. | |
23646 | ||
23647 | @item value | |
23648 | The varobj's scalar value. For a varobj whose type is some sort of | |
23649 | aggregate (e.g., a @code{struct}), or for a dynamic varobj, this value | |
23650 | will not be interesting. | |
23651 | ||
23652 | @item type | |
23653 | The varobj's type. This is a string representation of the type, as | |
23654 | would be printed by the @value{GDBN} CLI. | |
23655 | ||
23656 | @item thread-id | |
23657 | If a variable object is bound to a specific thread, then this is the | |
23658 | thread's identifier. | |
23659 | ||
23660 | @item has_more | |
23661 | For a dynamic varobj, this indicates whether there appear to be any | |
23662 | children available. For a non-dynamic varobj, this will be 0. | |
23663 | ||
23664 | @item dynamic | |
23665 | This attribute will be present and have the value @samp{1} if the | |
23666 | varobj is a dynamic varobj. If the varobj is not a dynamic varobj, | |
23667 | then this attribute will not be present. | |
23668 | ||
23669 | @item displayhint | |
23670 | A dynamic varobj can supply a display hint to the front end. The | |
23671 | value comes directly from the Python pretty-printer object's | |
23672 | @code{display_hint} method. @xref{Pretty Printing}. | |
23673 | @end table | |
23674 | ||
23675 | Typical output will look like this: | |
922fbb7b AC |
23676 | |
23677 | @smallexample | |
0cc7d26f TT |
23678 | name="@var{name}",numchild="@var{N}",type="@var{type}",thread-id="@var{M}", |
23679 | has_more="@var{has_more}" | |
dcaaae04 NR |
23680 | @end smallexample |
23681 | ||
a2c02241 NR |
23682 | |
23683 | @subheading The @code{-var-delete} Command | |
23684 | @findex -var-delete | |
922fbb7b AC |
23685 | |
23686 | @subsubheading Synopsis | |
23687 | ||
23688 | @smallexample | |
22d8a470 | 23689 | -var-delete [ -c ] @var{name} |
922fbb7b AC |
23690 | @end smallexample |
23691 | ||
a2c02241 | 23692 | Deletes a previously created variable object and all of its children. |
22d8a470 | 23693 | With the @samp{-c} option, just deletes the children. |
922fbb7b | 23694 | |
a2c02241 | 23695 | Returns an error if the object @var{name} is not found. |
922fbb7b | 23696 | |
922fbb7b | 23697 | |
a2c02241 NR |
23698 | @subheading The @code{-var-set-format} Command |
23699 | @findex -var-set-format | |
922fbb7b | 23700 | |
a2c02241 | 23701 | @subsubheading Synopsis |
922fbb7b AC |
23702 | |
23703 | @smallexample | |
a2c02241 | 23704 | -var-set-format @var{name} @var{format-spec} |
922fbb7b AC |
23705 | @end smallexample |
23706 | ||
a2c02241 NR |
23707 | Sets the output format for the value of the object @var{name} to be |
23708 | @var{format-spec}. | |
23709 | ||
de051565 | 23710 | @anchor{-var-set-format} |
a2c02241 NR |
23711 | The syntax for the @var{format-spec} is as follows: |
23712 | ||
23713 | @smallexample | |
23714 | @var{format-spec} @expansion{} | |
23715 | @{binary | decimal | hexadecimal | octal | natural@} | |
23716 | @end smallexample | |
23717 | ||
c8b2f53c VP |
23718 | The natural format is the default format choosen automatically |
23719 | based on the variable type (like decimal for an @code{int}, hex | |
23720 | for pointers, etc.). | |
23721 | ||
23722 | For a variable with children, the format is set only on the | |
23723 | variable itself, and the children are not affected. | |
a2c02241 NR |
23724 | |
23725 | @subheading The @code{-var-show-format} Command | |
23726 | @findex -var-show-format | |
922fbb7b AC |
23727 | |
23728 | @subsubheading Synopsis | |
23729 | ||
23730 | @smallexample | |
a2c02241 | 23731 | -var-show-format @var{name} |
922fbb7b AC |
23732 | @end smallexample |
23733 | ||
a2c02241 | 23734 | Returns the format used to display the value of the object @var{name}. |
922fbb7b | 23735 | |
a2c02241 NR |
23736 | @smallexample |
23737 | @var{format} @expansion{} | |
23738 | @var{format-spec} | |
23739 | @end smallexample | |
922fbb7b | 23740 | |
922fbb7b | 23741 | |
a2c02241 NR |
23742 | @subheading The @code{-var-info-num-children} Command |
23743 | @findex -var-info-num-children | |
23744 | ||
23745 | @subsubheading Synopsis | |
23746 | ||
23747 | @smallexample | |
23748 | -var-info-num-children @var{name} | |
23749 | @end smallexample | |
23750 | ||
23751 | Returns the number of children of a variable object @var{name}: | |
23752 | ||
23753 | @smallexample | |
23754 | numchild=@var{n} | |
23755 | @end smallexample | |
23756 | ||
0cc7d26f TT |
23757 | Note that this number is not completely reliable for a dynamic varobj. |
23758 | It will return the current number of children, but more children may | |
23759 | be available. | |
23760 | ||
a2c02241 NR |
23761 | |
23762 | @subheading The @code{-var-list-children} Command | |
23763 | @findex -var-list-children | |
23764 | ||
23765 | @subsubheading Synopsis | |
23766 | ||
23767 | @smallexample | |
0cc7d26f | 23768 | -var-list-children [@var{print-values}] @var{name} [@var{from} @var{to}] |
a2c02241 | 23769 | @end smallexample |
b569d230 | 23770 | @anchor{-var-list-children} |
a2c02241 NR |
23771 | |
23772 | Return a list of the children of the specified variable object and | |
23773 | create variable objects for them, if they do not already exist. With | |
23774 | a single argument or if @var{print-values} has a value for of 0 or | |
23775 | @code{--no-values}, print only the names of the variables; if | |
23776 | @var{print-values} is 1 or @code{--all-values}, also print their | |
23777 | values; and if it is 2 or @code{--simple-values} print the name and | |
23778 | value for simple data types and just the name for arrays, structures | |
23779 | and unions. | |
922fbb7b | 23780 | |
0cc7d26f TT |
23781 | @var{from} and @var{to}, if specified, indicate the range of children |
23782 | to report. If @var{from} or @var{to} is less than zero, the range is | |
23783 | reset and all children will be reported. Otherwise, children starting | |
23784 | at @var{from} (zero-based) and up to and excluding @var{to} will be | |
23785 | reported. | |
23786 | ||
23787 | If a child range is requested, it will only affect the current call to | |
23788 | @code{-var-list-children}, but not future calls to @code{-var-update}. | |
23789 | For this, you must instead use @code{-var-set-update-range}. The | |
23790 | intent of this approach is to enable a front end to implement any | |
23791 | update approach it likes; for example, scrolling a view may cause the | |
23792 | front end to request more children with @code{-var-list-children}, and | |
23793 | then the front end could call @code{-var-set-update-range} with a | |
23794 | different range to ensure that future updates are restricted to just | |
23795 | the visible items. | |
23796 | ||
b569d230 EZ |
23797 | For each child the following results are returned: |
23798 | ||
23799 | @table @var | |
23800 | ||
23801 | @item name | |
23802 | Name of the variable object created for this child. | |
23803 | ||
23804 | @item exp | |
23805 | The expression to be shown to the user by the front end to designate this child. | |
23806 | For example this may be the name of a structure member. | |
23807 | ||
0cc7d26f TT |
23808 | For a dynamic varobj, this value cannot be used to form an |
23809 | expression. There is no way to do this at all with a dynamic varobj. | |
23810 | ||
b569d230 EZ |
23811 | For C/C@t{++} structures there are several pseudo children returned to |
23812 | designate access qualifiers. For these pseudo children @var{exp} is | |
23813 | @samp{public}, @samp{private}, or @samp{protected}. In this case the | |
23814 | type and value are not present. | |
23815 | ||
0cc7d26f TT |
23816 | A dynamic varobj will not report the access qualifying |
23817 | pseudo-children, regardless of the language. This information is not | |
23818 | available at all with a dynamic varobj. | |
23819 | ||
b569d230 | 23820 | @item numchild |
0cc7d26f TT |
23821 | Number of children this child has. For a dynamic varobj, this will be |
23822 | 0. | |
b569d230 EZ |
23823 | |
23824 | @item type | |
23825 | The type of the child. | |
23826 | ||
23827 | @item value | |
23828 | If values were requested, this is the value. | |
23829 | ||
23830 | @item thread-id | |
23831 | If this variable object is associated with a thread, this is the thread id. | |
23832 | Otherwise this result is not present. | |
23833 | ||
23834 | @item frozen | |
23835 | If the variable object is frozen, this variable will be present with a value of 1. | |
23836 | @end table | |
23837 | ||
0cc7d26f TT |
23838 | The result may have its own attributes: |
23839 | ||
23840 | @table @samp | |
23841 | @item displayhint | |
23842 | A dynamic varobj can supply a display hint to the front end. The | |
23843 | value comes directly from the Python pretty-printer object's | |
23844 | @code{display_hint} method. @xref{Pretty Printing}. | |
23845 | ||
23846 | @item has_more | |
23847 | This is an integer attribute which is nonzero if there are children | |
23848 | remaining after the end of the selected range. | |
23849 | @end table | |
23850 | ||
922fbb7b AC |
23851 | @subsubheading Example |
23852 | ||
23853 | @smallexample | |
594fe323 | 23854 | (gdb) |
a2c02241 | 23855 | -var-list-children n |
b569d230 | 23856 | ^done,numchild=@var{n},children=[child=@{name=@var{name},exp=@var{exp}, |
a2c02241 | 23857 | numchild=@var{n},type=@var{type}@},@r{(repeats N times)}] |
594fe323 | 23858 | (gdb) |
a2c02241 | 23859 | -var-list-children --all-values n |
b569d230 | 23860 | ^done,numchild=@var{n},children=[child=@{name=@var{name},exp=@var{exp}, |
a2c02241 | 23861 | numchild=@var{n},value=@var{value},type=@var{type}@},@r{(repeats N times)}] |
922fbb7b AC |
23862 | @end smallexample |
23863 | ||
922fbb7b | 23864 | |
a2c02241 NR |
23865 | @subheading The @code{-var-info-type} Command |
23866 | @findex -var-info-type | |
922fbb7b | 23867 | |
a2c02241 NR |
23868 | @subsubheading Synopsis |
23869 | ||
23870 | @smallexample | |
23871 | -var-info-type @var{name} | |
23872 | @end smallexample | |
23873 | ||
23874 | Returns the type of the specified variable @var{name}. The type is | |
23875 | returned as a string in the same format as it is output by the | |
23876 | @value{GDBN} CLI: | |
23877 | ||
23878 | @smallexample | |
23879 | type=@var{typename} | |
23880 | @end smallexample | |
23881 | ||
23882 | ||
23883 | @subheading The @code{-var-info-expression} Command | |
23884 | @findex -var-info-expression | |
922fbb7b AC |
23885 | |
23886 | @subsubheading Synopsis | |
23887 | ||
23888 | @smallexample | |
a2c02241 | 23889 | -var-info-expression @var{name} |
922fbb7b AC |
23890 | @end smallexample |
23891 | ||
02142340 VP |
23892 | Returns a string that is suitable for presenting this |
23893 | variable object in user interface. The string is generally | |
23894 | not valid expression in the current language, and cannot be evaluated. | |
23895 | ||
23896 | For example, if @code{a} is an array, and variable object | |
23897 | @code{A} was created for @code{a}, then we'll get this output: | |
922fbb7b | 23898 | |
a2c02241 | 23899 | @smallexample |
02142340 VP |
23900 | (gdb) -var-info-expression A.1 |
23901 | ^done,lang="C",exp="1" | |
a2c02241 | 23902 | @end smallexample |
922fbb7b | 23903 | |
a2c02241 | 23904 | @noindent |
02142340 VP |
23905 | Here, the values of @code{lang} can be @code{@{"C" | "C++" | "Java"@}}. |
23906 | ||
23907 | Note that the output of the @code{-var-list-children} command also | |
23908 | includes those expressions, so the @code{-var-info-expression} command | |
23909 | is of limited use. | |
23910 | ||
23911 | @subheading The @code{-var-info-path-expression} Command | |
23912 | @findex -var-info-path-expression | |
23913 | ||
23914 | @subsubheading Synopsis | |
23915 | ||
23916 | @smallexample | |
23917 | -var-info-path-expression @var{name} | |
23918 | @end smallexample | |
23919 | ||
23920 | Returns an expression that can be evaluated in the current | |
23921 | context and will yield the same value that a variable object has. | |
23922 | Compare this with the @code{-var-info-expression} command, which | |
23923 | result can be used only for UI presentation. Typical use of | |
23924 | the @code{-var-info-path-expression} command is creating a | |
23925 | watchpoint from a variable object. | |
23926 | ||
0cc7d26f TT |
23927 | This command is currently not valid for children of a dynamic varobj, |
23928 | and will give an error when invoked on one. | |
23929 | ||
02142340 VP |
23930 | For example, suppose @code{C} is a C@t{++} class, derived from class |
23931 | @code{Base}, and that the @code{Base} class has a member called | |
23932 | @code{m_size}. Assume a variable @code{c} is has the type of | |
23933 | @code{C} and a variable object @code{C} was created for variable | |
23934 | @code{c}. Then, we'll get this output: | |
23935 | @smallexample | |
23936 | (gdb) -var-info-path-expression C.Base.public.m_size | |
23937 | ^done,path_expr=((Base)c).m_size) | |
23938 | @end smallexample | |
922fbb7b | 23939 | |
a2c02241 NR |
23940 | @subheading The @code{-var-show-attributes} Command |
23941 | @findex -var-show-attributes | |
922fbb7b | 23942 | |
a2c02241 | 23943 | @subsubheading Synopsis |
922fbb7b | 23944 | |
a2c02241 NR |
23945 | @smallexample |
23946 | -var-show-attributes @var{name} | |
23947 | @end smallexample | |
922fbb7b | 23948 | |
a2c02241 | 23949 | List attributes of the specified variable object @var{name}: |
922fbb7b AC |
23950 | |
23951 | @smallexample | |
a2c02241 | 23952 | status=@var{attr} [ ( ,@var{attr} )* ] |
922fbb7b AC |
23953 | @end smallexample |
23954 | ||
a2c02241 NR |
23955 | @noindent |
23956 | where @var{attr} is @code{@{ @{ editable | noneditable @} | TBD @}}. | |
23957 | ||
23958 | @subheading The @code{-var-evaluate-expression} Command | |
23959 | @findex -var-evaluate-expression | |
23960 | ||
23961 | @subsubheading Synopsis | |
23962 | ||
23963 | @smallexample | |
de051565 | 23964 | -var-evaluate-expression [-f @var{format-spec}] @var{name} |
a2c02241 NR |
23965 | @end smallexample |
23966 | ||
23967 | Evaluates the expression that is represented by the specified variable | |
de051565 MK |
23968 | object and returns its value as a string. The format of the string |
23969 | can be specified with the @samp{-f} option. The possible values of | |
23970 | this option are the same as for @code{-var-set-format} | |
23971 | (@pxref{-var-set-format}). If the @samp{-f} option is not specified, | |
23972 | the current display format will be used. The current display format | |
23973 | can be changed using the @code{-var-set-format} command. | |
a2c02241 NR |
23974 | |
23975 | @smallexample | |
23976 | value=@var{value} | |
23977 | @end smallexample | |
23978 | ||
23979 | Note that one must invoke @code{-var-list-children} for a variable | |
23980 | before the value of a child variable can be evaluated. | |
23981 | ||
23982 | @subheading The @code{-var-assign} Command | |
23983 | @findex -var-assign | |
23984 | ||
23985 | @subsubheading Synopsis | |
23986 | ||
23987 | @smallexample | |
23988 | -var-assign @var{name} @var{expression} | |
23989 | @end smallexample | |
23990 | ||
23991 | Assigns the value of @var{expression} to the variable object specified | |
23992 | by @var{name}. The object must be @samp{editable}. If the variable's | |
23993 | value is altered by the assign, the variable will show up in any | |
23994 | subsequent @code{-var-update} list. | |
23995 | ||
23996 | @subsubheading Example | |
922fbb7b AC |
23997 | |
23998 | @smallexample | |
594fe323 | 23999 | (gdb) |
a2c02241 NR |
24000 | -var-assign var1 3 |
24001 | ^done,value="3" | |
594fe323 | 24002 | (gdb) |
a2c02241 NR |
24003 | -var-update * |
24004 | ^done,changelist=[@{name="var1",in_scope="true",type_changed="false"@}] | |
594fe323 | 24005 | (gdb) |
922fbb7b AC |
24006 | @end smallexample |
24007 | ||
a2c02241 NR |
24008 | @subheading The @code{-var-update} Command |
24009 | @findex -var-update | |
24010 | ||
24011 | @subsubheading Synopsis | |
24012 | ||
24013 | @smallexample | |
24014 | -var-update [@var{print-values}] @{@var{name} | "*"@} | |
24015 | @end smallexample | |
24016 | ||
c8b2f53c VP |
24017 | Reevaluate the expressions corresponding to the variable object |
24018 | @var{name} and all its direct and indirect children, and return the | |
36ece8b3 NR |
24019 | list of variable objects whose values have changed; @var{name} must |
24020 | be a root variable object. Here, ``changed'' means that the result of | |
24021 | @code{-var-evaluate-expression} before and after the | |
24022 | @code{-var-update} is different. If @samp{*} is used as the variable | |
9f708cb2 VP |
24023 | object names, all existing variable objects are updated, except |
24024 | for frozen ones (@pxref{-var-set-frozen}). The option | |
36ece8b3 | 24025 | @var{print-values} determines whether both names and values, or just |
de051565 | 24026 | names are printed. The possible values of this option are the same |
36ece8b3 NR |
24027 | as for @code{-var-list-children} (@pxref{-var-list-children}). It is |
24028 | recommended to use the @samp{--all-values} option, to reduce the | |
24029 | number of MI commands needed on each program stop. | |
c8b2f53c | 24030 | |
c3b108f7 VP |
24031 | With the @samp{*} parameter, if a variable object is bound to a |
24032 | currently running thread, it will not be updated, without any | |
24033 | diagnostic. | |
a2c02241 | 24034 | |
0cc7d26f TT |
24035 | If @code{-var-set-update-range} was previously used on a varobj, then |
24036 | only the selected range of children will be reported. | |
922fbb7b | 24037 | |
0cc7d26f TT |
24038 | @code{-var-update} reports all the changed varobjs in a tuple named |
24039 | @samp{changelist}. | |
24040 | ||
24041 | Each item in the change list is itself a tuple holding: | |
24042 | ||
24043 | @table @samp | |
24044 | @item name | |
24045 | The name of the varobj. | |
24046 | ||
24047 | @item value | |
24048 | If values were requested for this update, then this field will be | |
24049 | present and will hold the value of the varobj. | |
922fbb7b | 24050 | |
0cc7d26f | 24051 | @item in_scope |
9f708cb2 | 24052 | @anchor{-var-update} |
0cc7d26f | 24053 | This field is a string which may take one of three values: |
36ece8b3 NR |
24054 | |
24055 | @table @code | |
24056 | @item "true" | |
24057 | The variable object's current value is valid. | |
24058 | ||
24059 | @item "false" | |
24060 | The variable object does not currently hold a valid value but it may | |
24061 | hold one in the future if its associated expression comes back into | |
24062 | scope. | |
24063 | ||
24064 | @item "invalid" | |
24065 | The variable object no longer holds a valid value. | |
24066 | This can occur when the executable file being debugged has changed, | |
24067 | either through recompilation or by using the @value{GDBN} @code{file} | |
24068 | command. The front end should normally choose to delete these variable | |
24069 | objects. | |
24070 | @end table | |
24071 | ||
24072 | In the future new values may be added to this list so the front should | |
24073 | be prepared for this possibility. @xref{GDB/MI Development and Front Ends, ,@sc{GDB/MI} Development and Front Ends}. | |
24074 | ||
0cc7d26f TT |
24075 | @item type_changed |
24076 | This is only present if the varobj is still valid. If the type | |
24077 | changed, then this will be the string @samp{true}; otherwise it will | |
24078 | be @samp{false}. | |
24079 | ||
24080 | @item new_type | |
24081 | If the varobj's type changed, then this field will be present and will | |
24082 | hold the new type. | |
24083 | ||
24084 | @item new_num_children | |
24085 | For a dynamic varobj, if the number of children changed, or if the | |
24086 | type changed, this will be the new number of children. | |
24087 | ||
24088 | The @samp{numchild} field in other varobj responses is generally not | |
24089 | valid for a dynamic varobj -- it will show the number of children that | |
24090 | @value{GDBN} knows about, but because dynamic varobjs lazily | |
24091 | instantiate their children, this will not reflect the number of | |
24092 | children which may be available. | |
24093 | ||
24094 | The @samp{new_num_children} attribute only reports changes to the | |
24095 | number of children known by @value{GDBN}. This is the only way to | |
24096 | detect whether an update has removed children (which necessarily can | |
24097 | only happen at the end of the update range). | |
24098 | ||
24099 | @item displayhint | |
24100 | The display hint, if any. | |
24101 | ||
24102 | @item has_more | |
24103 | This is an integer value, which will be 1 if there are more children | |
24104 | available outside the varobj's update range. | |
24105 | ||
24106 | @item dynamic | |
24107 | This attribute will be present and have the value @samp{1} if the | |
24108 | varobj is a dynamic varobj. If the varobj is not a dynamic varobj, | |
24109 | then this attribute will not be present. | |
24110 | ||
24111 | @item new_children | |
24112 | If new children were added to a dynamic varobj within the selected | |
24113 | update range (as set by @code{-var-set-update-range}), then they will | |
24114 | be listed in this attribute. | |
24115 | @end table | |
24116 | ||
24117 | @subsubheading Example | |
24118 | ||
24119 | @smallexample | |
24120 | (gdb) | |
24121 | -var-assign var1 3 | |
24122 | ^done,value="3" | |
24123 | (gdb) | |
24124 | -var-update --all-values var1 | |
24125 | ^done,changelist=[@{name="var1",value="3",in_scope="true", | |
24126 | type_changed="false"@}] | |
24127 | (gdb) | |
24128 | @end smallexample | |
24129 | ||
25d5ea92 VP |
24130 | @subheading The @code{-var-set-frozen} Command |
24131 | @findex -var-set-frozen | |
9f708cb2 | 24132 | @anchor{-var-set-frozen} |
25d5ea92 VP |
24133 | |
24134 | @subsubheading Synopsis | |
24135 | ||
24136 | @smallexample | |
9f708cb2 | 24137 | -var-set-frozen @var{name} @var{flag} |
25d5ea92 VP |
24138 | @end smallexample |
24139 | ||
9f708cb2 | 24140 | Set the frozenness flag on the variable object @var{name}. The |
25d5ea92 | 24141 | @var{flag} parameter should be either @samp{1} to make the variable |
9f708cb2 | 24142 | frozen or @samp{0} to make it unfrozen. If a variable object is |
25d5ea92 | 24143 | frozen, then neither itself, nor any of its children, are |
9f708cb2 | 24144 | implicitly updated by @code{-var-update} of |
25d5ea92 VP |
24145 | a parent variable or by @code{-var-update *}. Only |
24146 | @code{-var-update} of the variable itself will update its value and | |
24147 | values of its children. After a variable object is unfrozen, it is | |
24148 | implicitly updated by all subsequent @code{-var-update} operations. | |
24149 | Unfreezing a variable does not update it, only subsequent | |
24150 | @code{-var-update} does. | |
24151 | ||
24152 | @subsubheading Example | |
24153 | ||
24154 | @smallexample | |
24155 | (gdb) | |
24156 | -var-set-frozen V 1 | |
24157 | ^done | |
24158 | (gdb) | |
24159 | @end smallexample | |
24160 | ||
0cc7d26f TT |
24161 | @subheading The @code{-var-set-update-range} command |
24162 | @findex -var-set-update-range | |
24163 | @anchor{-var-set-update-range} | |
24164 | ||
24165 | @subsubheading Synopsis | |
24166 | ||
24167 | @smallexample | |
24168 | -var-set-update-range @var{name} @var{from} @var{to} | |
24169 | @end smallexample | |
24170 | ||
24171 | Set the range of children to be returned by future invocations of | |
24172 | @code{-var-update}. | |
24173 | ||
24174 | @var{from} and @var{to} indicate the range of children to report. If | |
24175 | @var{from} or @var{to} is less than zero, the range is reset and all | |
24176 | children will be reported. Otherwise, children starting at @var{from} | |
24177 | (zero-based) and up to and excluding @var{to} will be reported. | |
24178 | ||
24179 | @subsubheading Example | |
24180 | ||
24181 | @smallexample | |
24182 | (gdb) | |
24183 | -var-set-update-range V 1 2 | |
24184 | ^done | |
24185 | @end smallexample | |
24186 | ||
b6313243 TT |
24187 | @subheading The @code{-var-set-visualizer} command |
24188 | @findex -var-set-visualizer | |
24189 | @anchor{-var-set-visualizer} | |
24190 | ||
24191 | @subsubheading Synopsis | |
24192 | ||
24193 | @smallexample | |
24194 | -var-set-visualizer @var{name} @var{visualizer} | |
24195 | @end smallexample | |
24196 | ||
24197 | Set a visualizer for the variable object @var{name}. | |
24198 | ||
24199 | @var{visualizer} is the visualizer to use. The special value | |
24200 | @samp{None} means to disable any visualizer in use. | |
24201 | ||
24202 | If not @samp{None}, @var{visualizer} must be a Python expression. | |
24203 | This expression must evaluate to a callable object which accepts a | |
24204 | single argument. @value{GDBN} will call this object with the value of | |
24205 | the varobj @var{name} as an argument (this is done so that the same | |
24206 | Python pretty-printing code can be used for both the CLI and MI). | |
24207 | When called, this object must return an object which conforms to the | |
24208 | pretty-printing interface (@pxref{Pretty Printing}). | |
24209 | ||
24210 | The pre-defined function @code{gdb.default_visualizer} may be used to | |
24211 | select a visualizer by following the built-in process | |
24212 | (@pxref{Selecting Pretty-Printers}). This is done automatically when | |
24213 | a varobj is created, and so ordinarily is not needed. | |
24214 | ||
24215 | This feature is only available if Python support is enabled. The MI | |
24216 | command @code{-list-features} (@pxref{GDB/MI Miscellaneous Commands}) | |
24217 | can be used to check this. | |
24218 | ||
24219 | @subsubheading Example | |
24220 | ||
24221 | Resetting the visualizer: | |
24222 | ||
24223 | @smallexample | |
24224 | (gdb) | |
24225 | -var-set-visualizer V None | |
24226 | ^done | |
24227 | @end smallexample | |
24228 | ||
24229 | Reselecting the default (type-based) visualizer: | |
24230 | ||
24231 | @smallexample | |
24232 | (gdb) | |
24233 | -var-set-visualizer V gdb.default_visualizer | |
24234 | ^done | |
24235 | @end smallexample | |
24236 | ||
24237 | Suppose @code{SomeClass} is a visualizer class. A lambda expression | |
24238 | can be used to instantiate this class for a varobj: | |
24239 | ||
24240 | @smallexample | |
24241 | (gdb) | |
24242 | -var-set-visualizer V "lambda val: SomeClass()" | |
24243 | ^done | |
24244 | @end smallexample | |
25d5ea92 | 24245 | |
a2c02241 NR |
24246 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
24247 | @node GDB/MI Data Manipulation | |
24248 | @section @sc{gdb/mi} Data Manipulation | |
922fbb7b | 24249 | |
a2c02241 NR |
24250 | @cindex data manipulation, in @sc{gdb/mi} |
24251 | @cindex @sc{gdb/mi}, data manipulation | |
24252 | This section describes the @sc{gdb/mi} commands that manipulate data: | |
24253 | examine memory and registers, evaluate expressions, etc. | |
24254 | ||
24255 | @c REMOVED FROM THE INTERFACE. | |
24256 | @c @subheading -data-assign | |
24257 | @c Change the value of a program variable. Plenty of side effects. | |
79a6e687 | 24258 | @c @subsubheading GDB Command |
a2c02241 NR |
24259 | @c set variable |
24260 | @c @subsubheading Example | |
24261 | @c N.A. | |
24262 | ||
24263 | @subheading The @code{-data-disassemble} Command | |
24264 | @findex -data-disassemble | |
922fbb7b AC |
24265 | |
24266 | @subsubheading Synopsis | |
24267 | ||
24268 | @smallexample | |
a2c02241 NR |
24269 | -data-disassemble |
24270 | [ -s @var{start-addr} -e @var{end-addr} ] | |
24271 | | [ -f @var{filename} -l @var{linenum} [ -n @var{lines} ] ] | |
24272 | -- @var{mode} | |
922fbb7b AC |
24273 | @end smallexample |
24274 | ||
a2c02241 NR |
24275 | @noindent |
24276 | Where: | |
24277 | ||
24278 | @table @samp | |
24279 | @item @var{start-addr} | |
24280 | is the beginning address (or @code{$pc}) | |
24281 | @item @var{end-addr} | |
24282 | is the end address | |
24283 | @item @var{filename} | |
24284 | is the name of the file to disassemble | |
24285 | @item @var{linenum} | |
24286 | is the line number to disassemble around | |
24287 | @item @var{lines} | |
d3e8051b | 24288 | is the number of disassembly lines to be produced. If it is -1, |
a2c02241 NR |
24289 | the whole function will be disassembled, in case no @var{end-addr} is |
24290 | specified. If @var{end-addr} is specified as a non-zero value, and | |
24291 | @var{lines} is lower than the number of disassembly lines between | |
24292 | @var{start-addr} and @var{end-addr}, only @var{lines} lines are | |
24293 | displayed; if @var{lines} is higher than the number of lines between | |
24294 | @var{start-addr} and @var{end-addr}, only the lines up to @var{end-addr} | |
24295 | are displayed. | |
24296 | @item @var{mode} | |
24297 | is either 0 (meaning only disassembly) or 1 (meaning mixed source and | |
24298 | disassembly). | |
24299 | @end table | |
24300 | ||
24301 | @subsubheading Result | |
24302 | ||
24303 | The output for each instruction is composed of four fields: | |
24304 | ||
24305 | @itemize @bullet | |
24306 | @item Address | |
24307 | @item Func-name | |
24308 | @item Offset | |
24309 | @item Instruction | |
24310 | @end itemize | |
24311 | ||
24312 | Note that whatever included in the instruction field, is not manipulated | |
d3e8051b | 24313 | directly by @sc{gdb/mi}, i.e., it is not possible to adjust its format. |
922fbb7b AC |
24314 | |
24315 | @subsubheading @value{GDBN} Command | |
24316 | ||
a2c02241 | 24317 | There's no direct mapping from this command to the CLI. |
922fbb7b AC |
24318 | |
24319 | @subsubheading Example | |
24320 | ||
a2c02241 NR |
24321 | Disassemble from the current value of @code{$pc} to @code{$pc + 20}: |
24322 | ||
922fbb7b | 24323 | @smallexample |
594fe323 | 24324 | (gdb) |
a2c02241 NR |
24325 | -data-disassemble -s $pc -e "$pc + 20" -- 0 |
24326 | ^done, | |
24327 | asm_insns=[ | |
24328 | @{address="0x000107c0",func-name="main",offset="4", | |
24329 | inst="mov 2, %o0"@}, | |
24330 | @{address="0x000107c4",func-name="main",offset="8", | |
24331 | inst="sethi %hi(0x11800), %o2"@}, | |
24332 | @{address="0x000107c8",func-name="main",offset="12", | |
24333 | inst="or %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"@}, | |
24334 | @{address="0x000107cc",func-name="main",offset="16", | |
24335 | inst="sethi %hi(0x11800), %o2"@}, | |
24336 | @{address="0x000107d0",func-name="main",offset="20", | |
24337 | inst="or %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"@}] | |
594fe323 | 24338 | (gdb) |
a2c02241 NR |
24339 | @end smallexample |
24340 | ||
24341 | Disassemble the whole @code{main} function. Line 32 is part of | |
24342 | @code{main}. | |
24343 | ||
24344 | @smallexample | |
24345 | -data-disassemble -f basics.c -l 32 -- 0 | |
24346 | ^done,asm_insns=[ | |
24347 | @{address="0x000107bc",func-name="main",offset="0", | |
24348 | inst="save %sp, -112, %sp"@}, | |
24349 | @{address="0x000107c0",func-name="main",offset="4", | |
24350 | inst="mov 2, %o0"@}, | |
24351 | @{address="0x000107c4",func-name="main",offset="8", | |
24352 | inst="sethi %hi(0x11800), %o2"@}, | |
24353 | [@dots{}] | |
24354 | @{address="0x0001081c",func-name="main",offset="96",inst="ret "@}, | |
24355 | @{address="0x00010820",func-name="main",offset="100",inst="restore "@}] | |
594fe323 | 24356 | (gdb) |
922fbb7b AC |
24357 | @end smallexample |
24358 | ||
a2c02241 | 24359 | Disassemble 3 instructions from the start of @code{main}: |
922fbb7b | 24360 | |
a2c02241 | 24361 | @smallexample |
594fe323 | 24362 | (gdb) |
a2c02241 NR |
24363 | -data-disassemble -f basics.c -l 32 -n 3 -- 0 |
24364 | ^done,asm_insns=[ | |
24365 | @{address="0x000107bc",func-name="main",offset="0", | |
24366 | inst="save %sp, -112, %sp"@}, | |
24367 | @{address="0x000107c0",func-name="main",offset="4", | |
24368 | inst="mov 2, %o0"@}, | |
24369 | @{address="0x000107c4",func-name="main",offset="8", | |
24370 | inst="sethi %hi(0x11800), %o2"@}] | |
594fe323 | 24371 | (gdb) |
a2c02241 NR |
24372 | @end smallexample |
24373 | ||
24374 | Disassemble 3 instructions from the start of @code{main} in mixed mode: | |
24375 | ||
24376 | @smallexample | |
594fe323 | 24377 | (gdb) |
a2c02241 NR |
24378 | -data-disassemble -f basics.c -l 32 -n 3 -- 1 |
24379 | ^done,asm_insns=[ | |
24380 | src_and_asm_line=@{line="31", | |
24381 | file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ | |
24382 | testsuite/gdb.mi/basics.c",line_asm_insn=[ | |
24383 | @{address="0x000107bc",func-name="main",offset="0", | |
24384 | inst="save %sp, -112, %sp"@}]@}, | |
24385 | src_and_asm_line=@{line="32", | |
24386 | file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \ | |
24387 | testsuite/gdb.mi/basics.c",line_asm_insn=[ | |
24388 | @{address="0x000107c0",func-name="main",offset="4", | |
24389 | inst="mov 2, %o0"@}, | |
24390 | @{address="0x000107c4",func-name="main",offset="8", | |
24391 | inst="sethi %hi(0x11800), %o2"@}]@}] | |
594fe323 | 24392 | (gdb) |
a2c02241 NR |
24393 | @end smallexample |
24394 | ||
24395 | ||
24396 | @subheading The @code{-data-evaluate-expression} Command | |
24397 | @findex -data-evaluate-expression | |
922fbb7b AC |
24398 | |
24399 | @subsubheading Synopsis | |
24400 | ||
24401 | @smallexample | |
a2c02241 | 24402 | -data-evaluate-expression @var{expr} |
922fbb7b AC |
24403 | @end smallexample |
24404 | ||
a2c02241 NR |
24405 | Evaluate @var{expr} as an expression. The expression could contain an |
24406 | inferior function call. The function call will execute synchronously. | |
24407 | If the expression contains spaces, it must be enclosed in double quotes. | |
922fbb7b AC |
24408 | |
24409 | @subsubheading @value{GDBN} Command | |
24410 | ||
a2c02241 NR |
24411 | The corresponding @value{GDBN} commands are @samp{print}, @samp{output}, and |
24412 | @samp{call}. In @code{gdbtk} only, there's a corresponding | |
24413 | @samp{gdb_eval} command. | |
922fbb7b AC |
24414 | |
24415 | @subsubheading Example | |
24416 | ||
a2c02241 NR |
24417 | In the following example, the numbers that precede the commands are the |
24418 | @dfn{tokens} described in @ref{GDB/MI Command Syntax, ,@sc{gdb/mi} | |
24419 | Command Syntax}. Notice how @sc{gdb/mi} returns the same tokens in its | |
24420 | output. | |
24421 | ||
922fbb7b | 24422 | @smallexample |
a2c02241 NR |
24423 | 211-data-evaluate-expression A |
24424 | 211^done,value="1" | |
594fe323 | 24425 | (gdb) |
a2c02241 NR |
24426 | 311-data-evaluate-expression &A |
24427 | 311^done,value="0xefffeb7c" | |
594fe323 | 24428 | (gdb) |
a2c02241 NR |
24429 | 411-data-evaluate-expression A+3 |
24430 | 411^done,value="4" | |
594fe323 | 24431 | (gdb) |
a2c02241 NR |
24432 | 511-data-evaluate-expression "A + 3" |
24433 | 511^done,value="4" | |
594fe323 | 24434 | (gdb) |
a2c02241 | 24435 | @end smallexample |
922fbb7b AC |
24436 | |
24437 | ||
a2c02241 NR |
24438 | @subheading The @code{-data-list-changed-registers} Command |
24439 | @findex -data-list-changed-registers | |
922fbb7b AC |
24440 | |
24441 | @subsubheading Synopsis | |
24442 | ||
24443 | @smallexample | |
a2c02241 | 24444 | -data-list-changed-registers |
922fbb7b AC |
24445 | @end smallexample |
24446 | ||
a2c02241 | 24447 | Display a list of the registers that have changed. |
922fbb7b AC |
24448 | |
24449 | @subsubheading @value{GDBN} Command | |
24450 | ||
a2c02241 NR |
24451 | @value{GDBN} doesn't have a direct analog for this command; @code{gdbtk} |
24452 | has the corresponding command @samp{gdb_changed_register_list}. | |
922fbb7b AC |
24453 | |
24454 | @subsubheading Example | |
922fbb7b | 24455 | |
a2c02241 | 24456 | On a PPC MBX board: |
922fbb7b AC |
24457 | |
24458 | @smallexample | |
594fe323 | 24459 | (gdb) |
a2c02241 NR |
24460 | -exec-continue |
24461 | ^running | |
922fbb7b | 24462 | |
594fe323 | 24463 | (gdb) |
a47ec5fe AR |
24464 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",frame=@{ |
24465 | func="main",args=[],file="try.c",fullname="/home/foo/bar/try.c", | |
24466 | line="5"@} | |
594fe323 | 24467 | (gdb) |
a2c02241 NR |
24468 | -data-list-changed-registers |
24469 | ^done,changed-registers=["0","1","2","4","5","6","7","8","9", | |
24470 | "10","11","13","14","15","16","17","18","19","20","21","22","23", | |
24471 | "24","25","26","27","28","30","31","64","65","66","67","69"] | |
594fe323 | 24472 | (gdb) |
a2c02241 | 24473 | @end smallexample |
922fbb7b AC |
24474 | |
24475 | ||
a2c02241 NR |
24476 | @subheading The @code{-data-list-register-names} Command |
24477 | @findex -data-list-register-names | |
922fbb7b AC |
24478 | |
24479 | @subsubheading Synopsis | |
24480 | ||
24481 | @smallexample | |
a2c02241 | 24482 | -data-list-register-names [ ( @var{regno} )+ ] |
922fbb7b AC |
24483 | @end smallexample |
24484 | ||
a2c02241 NR |
24485 | Show a list of register names for the current target. If no arguments |
24486 | are given, it shows a list of the names of all the registers. If | |
24487 | integer numbers are given as arguments, it will print a list of the | |
24488 | names of the registers corresponding to the arguments. To ensure | |
24489 | consistency between a register name and its number, the output list may | |
24490 | include empty register names. | |
922fbb7b AC |
24491 | |
24492 | @subsubheading @value{GDBN} Command | |
24493 | ||
a2c02241 NR |
24494 | @value{GDBN} does not have a command which corresponds to |
24495 | @samp{-data-list-register-names}. In @code{gdbtk} there is a | |
24496 | corresponding command @samp{gdb_regnames}. | |
922fbb7b AC |
24497 | |
24498 | @subsubheading Example | |
922fbb7b | 24499 | |
a2c02241 NR |
24500 | For the PPC MBX board: |
24501 | @smallexample | |
594fe323 | 24502 | (gdb) |
a2c02241 NR |
24503 | -data-list-register-names |
24504 | ^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7", | |
24505 | "r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18", | |
24506 | "r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29", | |
24507 | "r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9", | |
24508 | "f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20", | |
24509 | "f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31", | |
24510 | "", "pc","ps","cr","lr","ctr","xer"] | |
594fe323 | 24511 | (gdb) |
a2c02241 NR |
24512 | -data-list-register-names 1 2 3 |
24513 | ^done,register-names=["r1","r2","r3"] | |
594fe323 | 24514 | (gdb) |
a2c02241 | 24515 | @end smallexample |
922fbb7b | 24516 | |
a2c02241 NR |
24517 | @subheading The @code{-data-list-register-values} Command |
24518 | @findex -data-list-register-values | |
922fbb7b AC |
24519 | |
24520 | @subsubheading Synopsis | |
24521 | ||
24522 | @smallexample | |
a2c02241 | 24523 | -data-list-register-values @var{fmt} [ ( @var{regno} )*] |
922fbb7b AC |
24524 | @end smallexample |
24525 | ||
a2c02241 NR |
24526 | Display the registers' contents. @var{fmt} is the format according to |
24527 | which the registers' contents are to be returned, followed by an optional | |
24528 | list of numbers specifying the registers to display. A missing list of | |
24529 | numbers indicates that the contents of all the registers must be returned. | |
24530 | ||
24531 | Allowed formats for @var{fmt} are: | |
24532 | ||
24533 | @table @code | |
24534 | @item x | |
24535 | Hexadecimal | |
24536 | @item o | |
24537 | Octal | |
24538 | @item t | |
24539 | Binary | |
24540 | @item d | |
24541 | Decimal | |
24542 | @item r | |
24543 | Raw | |
24544 | @item N | |
24545 | Natural | |
24546 | @end table | |
922fbb7b AC |
24547 | |
24548 | @subsubheading @value{GDBN} Command | |
24549 | ||
a2c02241 NR |
24550 | The corresponding @value{GDBN} commands are @samp{info reg}, @samp{info |
24551 | all-reg}, and (in @code{gdbtk}) @samp{gdb_fetch_registers}. | |
922fbb7b AC |
24552 | |
24553 | @subsubheading Example | |
922fbb7b | 24554 | |
a2c02241 NR |
24555 | For a PPC MBX board (note: line breaks are for readability only, they |
24556 | don't appear in the actual output): | |
24557 | ||
24558 | @smallexample | |
594fe323 | 24559 | (gdb) |
a2c02241 NR |
24560 | -data-list-register-values r 64 65 |
24561 | ^done,register-values=[@{number="64",value="0xfe00a300"@}, | |
24562 | @{number="65",value="0x00029002"@}] | |
594fe323 | 24563 | (gdb) |
a2c02241 NR |
24564 | -data-list-register-values x |
24565 | ^done,register-values=[@{number="0",value="0xfe0043c8"@}, | |
24566 | @{number="1",value="0x3fff88"@},@{number="2",value="0xfffffffe"@}, | |
24567 | @{number="3",value="0x0"@},@{number="4",value="0xa"@}, | |
24568 | @{number="5",value="0x3fff68"@},@{number="6",value="0x3fff58"@}, | |
24569 | @{number="7",value="0xfe011e98"@},@{number="8",value="0x2"@}, | |
24570 | @{number="9",value="0xfa202820"@},@{number="10",value="0xfa202808"@}, | |
24571 | @{number="11",value="0x1"@},@{number="12",value="0x0"@}, | |
24572 | @{number="13",value="0x4544"@},@{number="14",value="0xffdfffff"@}, | |
24573 | @{number="15",value="0xffffffff"@},@{number="16",value="0xfffffeff"@}, | |
24574 | @{number="17",value="0xefffffed"@},@{number="18",value="0xfffffffe"@}, | |
24575 | @{number="19",value="0xffffffff"@},@{number="20",value="0xffffffff"@}, | |
24576 | @{number="21",value="0xffffffff"@},@{number="22",value="0xfffffff7"@}, | |
24577 | @{number="23",value="0xffffffff"@},@{number="24",value="0xffffffff"@}, | |
24578 | @{number="25",value="0xffffffff"@},@{number="26",value="0xfffffffb"@}, | |
24579 | @{number="27",value="0xffffffff"@},@{number="28",value="0xf7bfffff"@}, | |
24580 | @{number="29",value="0x0"@},@{number="30",value="0xfe010000"@}, | |
24581 | @{number="31",value="0x0"@},@{number="32",value="0x0"@}, | |
24582 | @{number="33",value="0x0"@},@{number="34",value="0x0"@}, | |
24583 | @{number="35",value="0x0"@},@{number="36",value="0x0"@}, | |
24584 | @{number="37",value="0x0"@},@{number="38",value="0x0"@}, | |
24585 | @{number="39",value="0x0"@},@{number="40",value="0x0"@}, | |
24586 | @{number="41",value="0x0"@},@{number="42",value="0x0"@}, | |
24587 | @{number="43",value="0x0"@},@{number="44",value="0x0"@}, | |
24588 | @{number="45",value="0x0"@},@{number="46",value="0x0"@}, | |
24589 | @{number="47",value="0x0"@},@{number="48",value="0x0"@}, | |
24590 | @{number="49",value="0x0"@},@{number="50",value="0x0"@}, | |
24591 | @{number="51",value="0x0"@},@{number="52",value="0x0"@}, | |
24592 | @{number="53",value="0x0"@},@{number="54",value="0x0"@}, | |
24593 | @{number="55",value="0x0"@},@{number="56",value="0x0"@}, | |
24594 | @{number="57",value="0x0"@},@{number="58",value="0x0"@}, | |
24595 | @{number="59",value="0x0"@},@{number="60",value="0x0"@}, | |
24596 | @{number="61",value="0x0"@},@{number="62",value="0x0"@}, | |
24597 | @{number="63",value="0x0"@},@{number="64",value="0xfe00a300"@}, | |
24598 | @{number="65",value="0x29002"@},@{number="66",value="0x202f04b5"@}, | |
24599 | @{number="67",value="0xfe0043b0"@},@{number="68",value="0xfe00b3e4"@}, | |
24600 | @{number="69",value="0x20002b03"@}] | |
594fe323 | 24601 | (gdb) |
a2c02241 | 24602 | @end smallexample |
922fbb7b | 24603 | |
a2c02241 NR |
24604 | |
24605 | @subheading The @code{-data-read-memory} Command | |
24606 | @findex -data-read-memory | |
922fbb7b AC |
24607 | |
24608 | @subsubheading Synopsis | |
24609 | ||
24610 | @smallexample | |
a2c02241 NR |
24611 | -data-read-memory [ -o @var{byte-offset} ] |
24612 | @var{address} @var{word-format} @var{word-size} | |
24613 | @var{nr-rows} @var{nr-cols} [ @var{aschar} ] | |
922fbb7b AC |
24614 | @end smallexample |
24615 | ||
a2c02241 NR |
24616 | @noindent |
24617 | where: | |
922fbb7b | 24618 | |
a2c02241 NR |
24619 | @table @samp |
24620 | @item @var{address} | |
24621 | An expression specifying the address of the first memory word to be | |
24622 | read. Complex expressions containing embedded white space should be | |
24623 | quoted using the C convention. | |
922fbb7b | 24624 | |
a2c02241 NR |
24625 | @item @var{word-format} |
24626 | The format to be used to print the memory words. The notation is the | |
24627 | same as for @value{GDBN}'s @code{print} command (@pxref{Output Formats, | |
79a6e687 | 24628 | ,Output Formats}). |
922fbb7b | 24629 | |
a2c02241 NR |
24630 | @item @var{word-size} |
24631 | The size of each memory word in bytes. | |
922fbb7b | 24632 | |
a2c02241 NR |
24633 | @item @var{nr-rows} |
24634 | The number of rows in the output table. | |
922fbb7b | 24635 | |
a2c02241 NR |
24636 | @item @var{nr-cols} |
24637 | The number of columns in the output table. | |
922fbb7b | 24638 | |
a2c02241 NR |
24639 | @item @var{aschar} |
24640 | If present, indicates that each row should include an @sc{ascii} dump. The | |
24641 | value of @var{aschar} is used as a padding character when a byte is not a | |
24642 | member of the printable @sc{ascii} character set (printable @sc{ascii} | |
24643 | characters are those whose code is between 32 and 126, inclusively). | |
922fbb7b | 24644 | |
a2c02241 NR |
24645 | @item @var{byte-offset} |
24646 | An offset to add to the @var{address} before fetching memory. | |
24647 | @end table | |
922fbb7b | 24648 | |
a2c02241 NR |
24649 | This command displays memory contents as a table of @var{nr-rows} by |
24650 | @var{nr-cols} words, each word being @var{word-size} bytes. In total, | |
24651 | @code{@var{nr-rows} * @var{nr-cols} * @var{word-size}} bytes are read | |
24652 | (returned as @samp{total-bytes}). Should less than the requested number | |
24653 | of bytes be returned by the target, the missing words are identified | |
24654 | using @samp{N/A}. The number of bytes read from the target is returned | |
24655 | in @samp{nr-bytes} and the starting address used to read memory in | |
24656 | @samp{addr}. | |
24657 | ||
24658 | The address of the next/previous row or page is available in | |
24659 | @samp{next-row} and @samp{prev-row}, @samp{next-page} and | |
24660 | @samp{prev-page}. | |
922fbb7b AC |
24661 | |
24662 | @subsubheading @value{GDBN} Command | |
24663 | ||
a2c02241 NR |
24664 | The corresponding @value{GDBN} command is @samp{x}. @code{gdbtk} has |
24665 | @samp{gdb_get_mem} memory read command. | |
922fbb7b AC |
24666 | |
24667 | @subsubheading Example | |
32e7087d | 24668 | |
a2c02241 NR |
24669 | Read six bytes of memory starting at @code{bytes+6} but then offset by |
24670 | @code{-6} bytes. Format as three rows of two columns. One byte per | |
24671 | word. Display each word in hex. | |
32e7087d JB |
24672 | |
24673 | @smallexample | |
594fe323 | 24674 | (gdb) |
a2c02241 NR |
24675 | 9-data-read-memory -o -6 -- bytes+6 x 1 3 2 |
24676 | 9^done,addr="0x00001390",nr-bytes="6",total-bytes="6", | |
24677 | next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396", | |
24678 | prev-page="0x0000138a",memory=[ | |
24679 | @{addr="0x00001390",data=["0x00","0x01"]@}, | |
24680 | @{addr="0x00001392",data=["0x02","0x03"]@}, | |
24681 | @{addr="0x00001394",data=["0x04","0x05"]@}] | |
594fe323 | 24682 | (gdb) |
32e7087d JB |
24683 | @end smallexample |
24684 | ||
a2c02241 NR |
24685 | Read two bytes of memory starting at address @code{shorts + 64} and |
24686 | display as a single word formatted in decimal. | |
32e7087d | 24687 | |
32e7087d | 24688 | @smallexample |
594fe323 | 24689 | (gdb) |
a2c02241 NR |
24690 | 5-data-read-memory shorts+64 d 2 1 1 |
24691 | 5^done,addr="0x00001510",nr-bytes="2",total-bytes="2", | |
24692 | next-row="0x00001512",prev-row="0x0000150e", | |
24693 | next-page="0x00001512",prev-page="0x0000150e",memory=[ | |
24694 | @{addr="0x00001510",data=["128"]@}] | |
594fe323 | 24695 | (gdb) |
32e7087d JB |
24696 | @end smallexample |
24697 | ||
a2c02241 NR |
24698 | Read thirty two bytes of memory starting at @code{bytes+16} and format |
24699 | as eight rows of four columns. Include a string encoding with @samp{x} | |
24700 | used as the non-printable character. | |
922fbb7b AC |
24701 | |
24702 | @smallexample | |
594fe323 | 24703 | (gdb) |
a2c02241 NR |
24704 | 4-data-read-memory bytes+16 x 1 8 4 x |
24705 | 4^done,addr="0x000013a0",nr-bytes="32",total-bytes="32", | |
24706 | next-row="0x000013c0",prev-row="0x0000139c", | |
24707 | next-page="0x000013c0",prev-page="0x00001380",memory=[ | |
24708 | @{addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"@}, | |
24709 | @{addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"@}, | |
24710 | @{addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"@}, | |
24711 | @{addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"@}, | |
24712 | @{addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"@}, | |
24713 | @{addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"@}, | |
24714 | @{addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"@}, | |
24715 | @{addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"@}] | |
594fe323 | 24716 | (gdb) |
922fbb7b AC |
24717 | @end smallexample |
24718 | ||
a2c02241 NR |
24719 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
24720 | @node GDB/MI Tracepoint Commands | |
24721 | @section @sc{gdb/mi} Tracepoint Commands | |
922fbb7b | 24722 | |
a2c02241 | 24723 | The tracepoint commands are not yet implemented. |
922fbb7b | 24724 | |
a2c02241 | 24725 | @c @subheading -trace-actions |
922fbb7b | 24726 | |
a2c02241 | 24727 | @c @subheading -trace-delete |
922fbb7b | 24728 | |
a2c02241 | 24729 | @c @subheading -trace-disable |
922fbb7b | 24730 | |
a2c02241 | 24731 | @c @subheading -trace-dump |
922fbb7b | 24732 | |
a2c02241 | 24733 | @c @subheading -trace-enable |
922fbb7b | 24734 | |
a2c02241 | 24735 | @c @subheading -trace-exists |
922fbb7b | 24736 | |
a2c02241 | 24737 | @c @subheading -trace-find |
922fbb7b | 24738 | |
a2c02241 | 24739 | @c @subheading -trace-frame-number |
922fbb7b | 24740 | |
a2c02241 | 24741 | @c @subheading -trace-info |
922fbb7b | 24742 | |
a2c02241 | 24743 | @c @subheading -trace-insert |
922fbb7b | 24744 | |
a2c02241 | 24745 | @c @subheading -trace-list |
922fbb7b | 24746 | |
a2c02241 | 24747 | @c @subheading -trace-pass-count |
922fbb7b | 24748 | |
a2c02241 | 24749 | @c @subheading -trace-save |
922fbb7b | 24750 | |
a2c02241 | 24751 | @c @subheading -trace-start |
922fbb7b | 24752 | |
a2c02241 | 24753 | @c @subheading -trace-stop |
922fbb7b | 24754 | |
922fbb7b | 24755 | |
a2c02241 NR |
24756 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
24757 | @node GDB/MI Symbol Query | |
24758 | @section @sc{gdb/mi} Symbol Query Commands | |
922fbb7b AC |
24759 | |
24760 | ||
9901a55b | 24761 | @ignore |
a2c02241 NR |
24762 | @subheading The @code{-symbol-info-address} Command |
24763 | @findex -symbol-info-address | |
922fbb7b AC |
24764 | |
24765 | @subsubheading Synopsis | |
24766 | ||
24767 | @smallexample | |
a2c02241 | 24768 | -symbol-info-address @var{symbol} |
922fbb7b AC |
24769 | @end smallexample |
24770 | ||
a2c02241 | 24771 | Describe where @var{symbol} is stored. |
922fbb7b AC |
24772 | |
24773 | @subsubheading @value{GDBN} Command | |
24774 | ||
a2c02241 | 24775 | The corresponding @value{GDBN} command is @samp{info address}. |
922fbb7b AC |
24776 | |
24777 | @subsubheading Example | |
24778 | N.A. | |
24779 | ||
24780 | ||
a2c02241 NR |
24781 | @subheading The @code{-symbol-info-file} Command |
24782 | @findex -symbol-info-file | |
922fbb7b AC |
24783 | |
24784 | @subsubheading Synopsis | |
24785 | ||
24786 | @smallexample | |
a2c02241 | 24787 | -symbol-info-file |
922fbb7b AC |
24788 | @end smallexample |
24789 | ||
a2c02241 | 24790 | Show the file for the symbol. |
922fbb7b | 24791 | |
a2c02241 | 24792 | @subsubheading @value{GDBN} Command |
922fbb7b | 24793 | |
a2c02241 NR |
24794 | There's no equivalent @value{GDBN} command. @code{gdbtk} has |
24795 | @samp{gdb_find_file}. | |
922fbb7b AC |
24796 | |
24797 | @subsubheading Example | |
24798 | N.A. | |
24799 | ||
24800 | ||
a2c02241 NR |
24801 | @subheading The @code{-symbol-info-function} Command |
24802 | @findex -symbol-info-function | |
922fbb7b AC |
24803 | |
24804 | @subsubheading Synopsis | |
24805 | ||
24806 | @smallexample | |
a2c02241 | 24807 | -symbol-info-function |
922fbb7b AC |
24808 | @end smallexample |
24809 | ||
a2c02241 | 24810 | Show which function the symbol lives in. |
922fbb7b AC |
24811 | |
24812 | @subsubheading @value{GDBN} Command | |
24813 | ||
a2c02241 | 24814 | @samp{gdb_get_function} in @code{gdbtk}. |
922fbb7b AC |
24815 | |
24816 | @subsubheading Example | |
24817 | N.A. | |
24818 | ||
24819 | ||
a2c02241 NR |
24820 | @subheading The @code{-symbol-info-line} Command |
24821 | @findex -symbol-info-line | |
922fbb7b AC |
24822 | |
24823 | @subsubheading Synopsis | |
24824 | ||
24825 | @smallexample | |
a2c02241 | 24826 | -symbol-info-line |
922fbb7b AC |
24827 | @end smallexample |
24828 | ||
a2c02241 | 24829 | Show the core addresses of the code for a source line. |
922fbb7b | 24830 | |
a2c02241 | 24831 | @subsubheading @value{GDBN} Command |
922fbb7b | 24832 | |
a2c02241 NR |
24833 | The corresponding @value{GDBN} command is @samp{info line}. |
24834 | @code{gdbtk} has the @samp{gdb_get_line} and @samp{gdb_get_file} commands. | |
922fbb7b AC |
24835 | |
24836 | @subsubheading Example | |
a2c02241 | 24837 | N.A. |
922fbb7b AC |
24838 | |
24839 | ||
a2c02241 NR |
24840 | @subheading The @code{-symbol-info-symbol} Command |
24841 | @findex -symbol-info-symbol | |
07f31aa6 DJ |
24842 | |
24843 | @subsubheading Synopsis | |
24844 | ||
a2c02241 NR |
24845 | @smallexample |
24846 | -symbol-info-symbol @var{addr} | |
24847 | @end smallexample | |
07f31aa6 | 24848 | |
a2c02241 | 24849 | Describe what symbol is at location @var{addr}. |
07f31aa6 | 24850 | |
a2c02241 | 24851 | @subsubheading @value{GDBN} Command |
07f31aa6 | 24852 | |
a2c02241 | 24853 | The corresponding @value{GDBN} command is @samp{info symbol}. |
07f31aa6 DJ |
24854 | |
24855 | @subsubheading Example | |
a2c02241 | 24856 | N.A. |
07f31aa6 DJ |
24857 | |
24858 | ||
a2c02241 NR |
24859 | @subheading The @code{-symbol-list-functions} Command |
24860 | @findex -symbol-list-functions | |
922fbb7b AC |
24861 | |
24862 | @subsubheading Synopsis | |
24863 | ||
24864 | @smallexample | |
a2c02241 | 24865 | -symbol-list-functions |
922fbb7b AC |
24866 | @end smallexample |
24867 | ||
a2c02241 | 24868 | List the functions in the executable. |
922fbb7b AC |
24869 | |
24870 | @subsubheading @value{GDBN} Command | |
24871 | ||
a2c02241 NR |
24872 | @samp{info functions} in @value{GDBN}, @samp{gdb_listfunc} and |
24873 | @samp{gdb_search} in @code{gdbtk}. | |
922fbb7b AC |
24874 | |
24875 | @subsubheading Example | |
a2c02241 | 24876 | N.A. |
9901a55b | 24877 | @end ignore |
922fbb7b AC |
24878 | |
24879 | ||
a2c02241 NR |
24880 | @subheading The @code{-symbol-list-lines} Command |
24881 | @findex -symbol-list-lines | |
922fbb7b AC |
24882 | |
24883 | @subsubheading Synopsis | |
24884 | ||
24885 | @smallexample | |
a2c02241 | 24886 | -symbol-list-lines @var{filename} |
922fbb7b AC |
24887 | @end smallexample |
24888 | ||
a2c02241 NR |
24889 | Print the list of lines that contain code and their associated program |
24890 | addresses for the given source filename. The entries are sorted in | |
24891 | ascending PC order. | |
922fbb7b AC |
24892 | |
24893 | @subsubheading @value{GDBN} Command | |
24894 | ||
a2c02241 | 24895 | There is no corresponding @value{GDBN} command. |
922fbb7b AC |
24896 | |
24897 | @subsubheading Example | |
a2c02241 | 24898 | @smallexample |
594fe323 | 24899 | (gdb) |
a2c02241 NR |
24900 | -symbol-list-lines basics.c |
24901 | ^done,lines=[@{pc="0x08048554",line="7"@},@{pc="0x0804855a",line="8"@}] | |
594fe323 | 24902 | (gdb) |
a2c02241 | 24903 | @end smallexample |
922fbb7b AC |
24904 | |
24905 | ||
9901a55b | 24906 | @ignore |
a2c02241 NR |
24907 | @subheading The @code{-symbol-list-types} Command |
24908 | @findex -symbol-list-types | |
922fbb7b AC |
24909 | |
24910 | @subsubheading Synopsis | |
24911 | ||
24912 | @smallexample | |
a2c02241 | 24913 | -symbol-list-types |
922fbb7b AC |
24914 | @end smallexample |
24915 | ||
a2c02241 | 24916 | List all the type names. |
922fbb7b AC |
24917 | |
24918 | @subsubheading @value{GDBN} Command | |
24919 | ||
a2c02241 NR |
24920 | The corresponding commands are @samp{info types} in @value{GDBN}, |
24921 | @samp{gdb_search} in @code{gdbtk}. | |
922fbb7b AC |
24922 | |
24923 | @subsubheading Example | |
24924 | N.A. | |
24925 | ||
24926 | ||
a2c02241 NR |
24927 | @subheading The @code{-symbol-list-variables} Command |
24928 | @findex -symbol-list-variables | |
922fbb7b AC |
24929 | |
24930 | @subsubheading Synopsis | |
24931 | ||
24932 | @smallexample | |
a2c02241 | 24933 | -symbol-list-variables |
922fbb7b AC |
24934 | @end smallexample |
24935 | ||
a2c02241 | 24936 | List all the global and static variable names. |
922fbb7b AC |
24937 | |
24938 | @subsubheading @value{GDBN} Command | |
24939 | ||
a2c02241 | 24940 | @samp{info variables} in @value{GDBN}, @samp{gdb_search} in @code{gdbtk}. |
922fbb7b AC |
24941 | |
24942 | @subsubheading Example | |
24943 | N.A. | |
24944 | ||
24945 | ||
a2c02241 NR |
24946 | @subheading The @code{-symbol-locate} Command |
24947 | @findex -symbol-locate | |
922fbb7b AC |
24948 | |
24949 | @subsubheading Synopsis | |
24950 | ||
24951 | @smallexample | |
a2c02241 | 24952 | -symbol-locate |
922fbb7b AC |
24953 | @end smallexample |
24954 | ||
922fbb7b AC |
24955 | @subsubheading @value{GDBN} Command |
24956 | ||
a2c02241 | 24957 | @samp{gdb_loc} in @code{gdbtk}. |
922fbb7b AC |
24958 | |
24959 | @subsubheading Example | |
24960 | N.A. | |
24961 | ||
24962 | ||
a2c02241 NR |
24963 | @subheading The @code{-symbol-type} Command |
24964 | @findex -symbol-type | |
922fbb7b AC |
24965 | |
24966 | @subsubheading Synopsis | |
24967 | ||
24968 | @smallexample | |
a2c02241 | 24969 | -symbol-type @var{variable} |
922fbb7b AC |
24970 | @end smallexample |
24971 | ||
a2c02241 | 24972 | Show type of @var{variable}. |
922fbb7b | 24973 | |
a2c02241 | 24974 | @subsubheading @value{GDBN} Command |
922fbb7b | 24975 | |
a2c02241 NR |
24976 | The corresponding @value{GDBN} command is @samp{ptype}, @code{gdbtk} has |
24977 | @samp{gdb_obj_variable}. | |
24978 | ||
24979 | @subsubheading Example | |
24980 | N.A. | |
9901a55b | 24981 | @end ignore |
a2c02241 NR |
24982 | |
24983 | ||
24984 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% | |
24985 | @node GDB/MI File Commands | |
24986 | @section @sc{gdb/mi} File Commands | |
24987 | ||
24988 | This section describes the GDB/MI commands to specify executable file names | |
24989 | and to read in and obtain symbol table information. | |
24990 | ||
24991 | @subheading The @code{-file-exec-and-symbols} Command | |
24992 | @findex -file-exec-and-symbols | |
24993 | ||
24994 | @subsubheading Synopsis | |
922fbb7b AC |
24995 | |
24996 | @smallexample | |
a2c02241 | 24997 | -file-exec-and-symbols @var{file} |
922fbb7b AC |
24998 | @end smallexample |
24999 | ||
a2c02241 NR |
25000 | Specify the executable file to be debugged. This file is the one from |
25001 | which the symbol table is also read. If no file is specified, the | |
25002 | command clears the executable and symbol information. If breakpoints | |
25003 | are set when using this command with no arguments, @value{GDBN} will produce | |
25004 | error messages. Otherwise, no output is produced, except a completion | |
25005 | notification. | |
25006 | ||
922fbb7b AC |
25007 | @subsubheading @value{GDBN} Command |
25008 | ||
a2c02241 | 25009 | The corresponding @value{GDBN} command is @samp{file}. |
922fbb7b AC |
25010 | |
25011 | @subsubheading Example | |
25012 | ||
25013 | @smallexample | |
594fe323 | 25014 | (gdb) |
a2c02241 NR |
25015 | -file-exec-and-symbols /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25016 | ^done | |
594fe323 | 25017 | (gdb) |
922fbb7b AC |
25018 | @end smallexample |
25019 | ||
922fbb7b | 25020 | |
a2c02241 NR |
25021 | @subheading The @code{-file-exec-file} Command |
25022 | @findex -file-exec-file | |
922fbb7b AC |
25023 | |
25024 | @subsubheading Synopsis | |
25025 | ||
25026 | @smallexample | |
a2c02241 | 25027 | -file-exec-file @var{file} |
922fbb7b AC |
25028 | @end smallexample |
25029 | ||
a2c02241 NR |
25030 | Specify the executable file to be debugged. Unlike |
25031 | @samp{-file-exec-and-symbols}, the symbol table is @emph{not} read | |
25032 | from this file. If used without argument, @value{GDBN} clears the information | |
25033 | about the executable file. No output is produced, except a completion | |
25034 | notification. | |
922fbb7b | 25035 | |
a2c02241 NR |
25036 | @subsubheading @value{GDBN} Command |
25037 | ||
25038 | The corresponding @value{GDBN} command is @samp{exec-file}. | |
922fbb7b AC |
25039 | |
25040 | @subsubheading Example | |
a2c02241 NR |
25041 | |
25042 | @smallexample | |
594fe323 | 25043 | (gdb) |
a2c02241 NR |
25044 | -file-exec-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25045 | ^done | |
594fe323 | 25046 | (gdb) |
a2c02241 | 25047 | @end smallexample |
922fbb7b AC |
25048 | |
25049 | ||
9901a55b | 25050 | @ignore |
a2c02241 NR |
25051 | @subheading The @code{-file-list-exec-sections} Command |
25052 | @findex -file-list-exec-sections | |
922fbb7b AC |
25053 | |
25054 | @subsubheading Synopsis | |
25055 | ||
25056 | @smallexample | |
a2c02241 | 25057 | -file-list-exec-sections |
922fbb7b AC |
25058 | @end smallexample |
25059 | ||
a2c02241 NR |
25060 | List the sections of the current executable file. |
25061 | ||
922fbb7b AC |
25062 | @subsubheading @value{GDBN} Command |
25063 | ||
a2c02241 NR |
25064 | The @value{GDBN} command @samp{info file} shows, among the rest, the same |
25065 | information as this command. @code{gdbtk} has a corresponding command | |
25066 | @samp{gdb_load_info}. | |
922fbb7b AC |
25067 | |
25068 | @subsubheading Example | |
25069 | N.A. | |
9901a55b | 25070 | @end ignore |
922fbb7b AC |
25071 | |
25072 | ||
a2c02241 NR |
25073 | @subheading The @code{-file-list-exec-source-file} Command |
25074 | @findex -file-list-exec-source-file | |
922fbb7b AC |
25075 | |
25076 | @subsubheading Synopsis | |
25077 | ||
25078 | @smallexample | |
a2c02241 | 25079 | -file-list-exec-source-file |
922fbb7b AC |
25080 | @end smallexample |
25081 | ||
a2c02241 | 25082 | List the line number, the current source file, and the absolute path |
44288b44 NR |
25083 | to the current source file for the current executable. The macro |
25084 | information field has a value of @samp{1} or @samp{0} depending on | |
25085 | whether or not the file includes preprocessor macro information. | |
922fbb7b AC |
25086 | |
25087 | @subsubheading @value{GDBN} Command | |
25088 | ||
a2c02241 | 25089 | The @value{GDBN} equivalent is @samp{info source} |
922fbb7b AC |
25090 | |
25091 | @subsubheading Example | |
25092 | ||
922fbb7b | 25093 | @smallexample |
594fe323 | 25094 | (gdb) |
a2c02241 | 25095 | 123-file-list-exec-source-file |
44288b44 | 25096 | 123^done,line="1",file="foo.c",fullname="/home/bar/foo.c,macro-info="1" |
594fe323 | 25097 | (gdb) |
922fbb7b AC |
25098 | @end smallexample |
25099 | ||
25100 | ||
a2c02241 NR |
25101 | @subheading The @code{-file-list-exec-source-files} Command |
25102 | @findex -file-list-exec-source-files | |
922fbb7b AC |
25103 | |
25104 | @subsubheading Synopsis | |
25105 | ||
25106 | @smallexample | |
a2c02241 | 25107 | -file-list-exec-source-files |
922fbb7b AC |
25108 | @end smallexample |
25109 | ||
a2c02241 NR |
25110 | List the source files for the current executable. |
25111 | ||
3f94c067 BW |
25112 | It will always output the filename, but only when @value{GDBN} can find |
25113 | the absolute file name of a source file, will it output the fullname. | |
922fbb7b AC |
25114 | |
25115 | @subsubheading @value{GDBN} Command | |
25116 | ||
a2c02241 NR |
25117 | The @value{GDBN} equivalent is @samp{info sources}. |
25118 | @code{gdbtk} has an analogous command @samp{gdb_listfiles}. | |
922fbb7b AC |
25119 | |
25120 | @subsubheading Example | |
922fbb7b | 25121 | @smallexample |
594fe323 | 25122 | (gdb) |
a2c02241 NR |
25123 | -file-list-exec-source-files |
25124 | ^done,files=[ | |
25125 | @{file=foo.c,fullname=/home/foo.c@}, | |
25126 | @{file=/home/bar.c,fullname=/home/bar.c@}, | |
25127 | @{file=gdb_could_not_find_fullpath.c@}] | |
594fe323 | 25128 | (gdb) |
922fbb7b AC |
25129 | @end smallexample |
25130 | ||
9901a55b | 25131 | @ignore |
a2c02241 NR |
25132 | @subheading The @code{-file-list-shared-libraries} Command |
25133 | @findex -file-list-shared-libraries | |
922fbb7b | 25134 | |
a2c02241 | 25135 | @subsubheading Synopsis |
922fbb7b | 25136 | |
a2c02241 NR |
25137 | @smallexample |
25138 | -file-list-shared-libraries | |
25139 | @end smallexample | |
922fbb7b | 25140 | |
a2c02241 | 25141 | List the shared libraries in the program. |
922fbb7b | 25142 | |
a2c02241 | 25143 | @subsubheading @value{GDBN} Command |
922fbb7b | 25144 | |
a2c02241 | 25145 | The corresponding @value{GDBN} command is @samp{info shared}. |
922fbb7b | 25146 | |
a2c02241 NR |
25147 | @subsubheading Example |
25148 | N.A. | |
922fbb7b AC |
25149 | |
25150 | ||
a2c02241 NR |
25151 | @subheading The @code{-file-list-symbol-files} Command |
25152 | @findex -file-list-symbol-files | |
922fbb7b | 25153 | |
a2c02241 | 25154 | @subsubheading Synopsis |
922fbb7b | 25155 | |
a2c02241 NR |
25156 | @smallexample |
25157 | -file-list-symbol-files | |
25158 | @end smallexample | |
922fbb7b | 25159 | |
a2c02241 | 25160 | List symbol files. |
922fbb7b | 25161 | |
a2c02241 | 25162 | @subsubheading @value{GDBN} Command |
922fbb7b | 25163 | |
a2c02241 | 25164 | The corresponding @value{GDBN} command is @samp{info file} (part of it). |
922fbb7b | 25165 | |
a2c02241 NR |
25166 | @subsubheading Example |
25167 | N.A. | |
9901a55b | 25168 | @end ignore |
922fbb7b | 25169 | |
922fbb7b | 25170 | |
a2c02241 NR |
25171 | @subheading The @code{-file-symbol-file} Command |
25172 | @findex -file-symbol-file | |
922fbb7b | 25173 | |
a2c02241 | 25174 | @subsubheading Synopsis |
922fbb7b | 25175 | |
a2c02241 NR |
25176 | @smallexample |
25177 | -file-symbol-file @var{file} | |
25178 | @end smallexample | |
922fbb7b | 25179 | |
a2c02241 NR |
25180 | Read symbol table info from the specified @var{file} argument. When |
25181 | used without arguments, clears @value{GDBN}'s symbol table info. No output is | |
25182 | produced, except for a completion notification. | |
922fbb7b | 25183 | |
a2c02241 | 25184 | @subsubheading @value{GDBN} Command |
922fbb7b | 25185 | |
a2c02241 | 25186 | The corresponding @value{GDBN} command is @samp{symbol-file}. |
922fbb7b | 25187 | |
a2c02241 | 25188 | @subsubheading Example |
922fbb7b | 25189 | |
a2c02241 | 25190 | @smallexample |
594fe323 | 25191 | (gdb) |
a2c02241 NR |
25192 | -file-symbol-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx |
25193 | ^done | |
594fe323 | 25194 | (gdb) |
a2c02241 | 25195 | @end smallexample |
922fbb7b | 25196 | |
a2c02241 | 25197 | @ignore |
a2c02241 NR |
25198 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25199 | @node GDB/MI Memory Overlay Commands | |
25200 | @section @sc{gdb/mi} Memory Overlay Commands | |
922fbb7b | 25201 | |
a2c02241 | 25202 | The memory overlay commands are not implemented. |
922fbb7b | 25203 | |
a2c02241 | 25204 | @c @subheading -overlay-auto |
922fbb7b | 25205 | |
a2c02241 | 25206 | @c @subheading -overlay-list-mapping-state |
922fbb7b | 25207 | |
a2c02241 | 25208 | @c @subheading -overlay-list-overlays |
922fbb7b | 25209 | |
a2c02241 | 25210 | @c @subheading -overlay-map |
922fbb7b | 25211 | |
a2c02241 | 25212 | @c @subheading -overlay-off |
922fbb7b | 25213 | |
a2c02241 | 25214 | @c @subheading -overlay-on |
922fbb7b | 25215 | |
a2c02241 | 25216 | @c @subheading -overlay-unmap |
922fbb7b | 25217 | |
a2c02241 NR |
25218 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25219 | @node GDB/MI Signal Handling Commands | |
25220 | @section @sc{gdb/mi} Signal Handling Commands | |
922fbb7b | 25221 | |
a2c02241 | 25222 | Signal handling commands are not implemented. |
922fbb7b | 25223 | |
a2c02241 | 25224 | @c @subheading -signal-handle |
922fbb7b | 25225 | |
a2c02241 | 25226 | @c @subheading -signal-list-handle-actions |
922fbb7b | 25227 | |
a2c02241 NR |
25228 | @c @subheading -signal-list-signal-types |
25229 | @end ignore | |
922fbb7b | 25230 | |
922fbb7b | 25231 | |
a2c02241 NR |
25232 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25233 | @node GDB/MI Target Manipulation | |
25234 | @section @sc{gdb/mi} Target Manipulation Commands | |
922fbb7b AC |
25235 | |
25236 | ||
a2c02241 NR |
25237 | @subheading The @code{-target-attach} Command |
25238 | @findex -target-attach | |
922fbb7b AC |
25239 | |
25240 | @subsubheading Synopsis | |
25241 | ||
25242 | @smallexample | |
c3b108f7 | 25243 | -target-attach @var{pid} | @var{gid} | @var{file} |
922fbb7b AC |
25244 | @end smallexample |
25245 | ||
c3b108f7 VP |
25246 | Attach to a process @var{pid} or a file @var{file} outside of |
25247 | @value{GDBN}, or a thread group @var{gid}. If attaching to a thread | |
25248 | group, the id previously returned by | |
25249 | @samp{-list-thread-groups --available} must be used. | |
922fbb7b | 25250 | |
79a6e687 | 25251 | @subsubheading @value{GDBN} Command |
922fbb7b | 25252 | |
a2c02241 | 25253 | The corresponding @value{GDBN} command is @samp{attach}. |
922fbb7b | 25254 | |
a2c02241 | 25255 | @subsubheading Example |
b56e7235 VP |
25256 | @smallexample |
25257 | (gdb) | |
25258 | -target-attach 34 | |
25259 | =thread-created,id="1" | |
5ae4183a | 25260 | *stopped,thread-id="1",frame=@{addr="0xb7f7e410",func="bar",args=[]@} |
b56e7235 VP |
25261 | ^done |
25262 | (gdb) | |
25263 | @end smallexample | |
a2c02241 | 25264 | |
9901a55b | 25265 | @ignore |
a2c02241 NR |
25266 | @subheading The @code{-target-compare-sections} Command |
25267 | @findex -target-compare-sections | |
922fbb7b AC |
25268 | |
25269 | @subsubheading Synopsis | |
25270 | ||
25271 | @smallexample | |
a2c02241 | 25272 | -target-compare-sections [ @var{section} ] |
922fbb7b AC |
25273 | @end smallexample |
25274 | ||
a2c02241 NR |
25275 | Compare data of section @var{section} on target to the exec file. |
25276 | Without the argument, all sections are compared. | |
922fbb7b | 25277 | |
a2c02241 | 25278 | @subsubheading @value{GDBN} Command |
922fbb7b | 25279 | |
a2c02241 | 25280 | The @value{GDBN} equivalent is @samp{compare-sections}. |
922fbb7b | 25281 | |
a2c02241 NR |
25282 | @subsubheading Example |
25283 | N.A. | |
9901a55b | 25284 | @end ignore |
a2c02241 NR |
25285 | |
25286 | ||
25287 | @subheading The @code{-target-detach} Command | |
25288 | @findex -target-detach | |
922fbb7b AC |
25289 | |
25290 | @subsubheading Synopsis | |
25291 | ||
25292 | @smallexample | |
c3b108f7 | 25293 | -target-detach [ @var{pid} | @var{gid} ] |
922fbb7b AC |
25294 | @end smallexample |
25295 | ||
a2c02241 | 25296 | Detach from the remote target which normally resumes its execution. |
c3b108f7 VP |
25297 | If either @var{pid} or @var{gid} is specified, detaches from either |
25298 | the specified process, or specified thread group. There's no output. | |
a2c02241 | 25299 | |
79a6e687 | 25300 | @subsubheading @value{GDBN} Command |
a2c02241 NR |
25301 | |
25302 | The corresponding @value{GDBN} command is @samp{detach}. | |
25303 | ||
25304 | @subsubheading Example | |
922fbb7b AC |
25305 | |
25306 | @smallexample | |
594fe323 | 25307 | (gdb) |
a2c02241 NR |
25308 | -target-detach |
25309 | ^done | |
594fe323 | 25310 | (gdb) |
922fbb7b AC |
25311 | @end smallexample |
25312 | ||
25313 | ||
a2c02241 NR |
25314 | @subheading The @code{-target-disconnect} Command |
25315 | @findex -target-disconnect | |
922fbb7b AC |
25316 | |
25317 | @subsubheading Synopsis | |
25318 | ||
123dc839 | 25319 | @smallexample |
a2c02241 | 25320 | -target-disconnect |
123dc839 | 25321 | @end smallexample |
922fbb7b | 25322 | |
a2c02241 NR |
25323 | Disconnect from the remote target. There's no output and the target is |
25324 | generally not resumed. | |
25325 | ||
79a6e687 | 25326 | @subsubheading @value{GDBN} Command |
a2c02241 NR |
25327 | |
25328 | The corresponding @value{GDBN} command is @samp{disconnect}. | |
bc8ced35 NR |
25329 | |
25330 | @subsubheading Example | |
922fbb7b AC |
25331 | |
25332 | @smallexample | |
594fe323 | 25333 | (gdb) |
a2c02241 NR |
25334 | -target-disconnect |
25335 | ^done | |
594fe323 | 25336 | (gdb) |
922fbb7b AC |
25337 | @end smallexample |
25338 | ||
25339 | ||
a2c02241 NR |
25340 | @subheading The @code{-target-download} Command |
25341 | @findex -target-download | |
922fbb7b AC |
25342 | |
25343 | @subsubheading Synopsis | |
25344 | ||
25345 | @smallexample | |
a2c02241 | 25346 | -target-download |
922fbb7b AC |
25347 | @end smallexample |
25348 | ||
a2c02241 NR |
25349 | Loads the executable onto the remote target. |
25350 | It prints out an update message every half second, which includes the fields: | |
25351 | ||
25352 | @table @samp | |
25353 | @item section | |
25354 | The name of the section. | |
25355 | @item section-sent | |
25356 | The size of what has been sent so far for that section. | |
25357 | @item section-size | |
25358 | The size of the section. | |
25359 | @item total-sent | |
25360 | The total size of what was sent so far (the current and the previous sections). | |
25361 | @item total-size | |
25362 | The size of the overall executable to download. | |
25363 | @end table | |
25364 | ||
25365 | @noindent | |
25366 | Each message is sent as status record (@pxref{GDB/MI Output Syntax, , | |
25367 | @sc{gdb/mi} Output Syntax}). | |
25368 | ||
25369 | In addition, it prints the name and size of the sections, as they are | |
25370 | downloaded. These messages include the following fields: | |
25371 | ||
25372 | @table @samp | |
25373 | @item section | |
25374 | The name of the section. | |
25375 | @item section-size | |
25376 | The size of the section. | |
25377 | @item total-size | |
25378 | The size of the overall executable to download. | |
25379 | @end table | |
25380 | ||
25381 | @noindent | |
25382 | At the end, a summary is printed. | |
25383 | ||
25384 | @subsubheading @value{GDBN} Command | |
25385 | ||
25386 | The corresponding @value{GDBN} command is @samp{load}. | |
25387 | ||
25388 | @subsubheading Example | |
25389 | ||
25390 | Note: each status message appears on a single line. Here the messages | |
25391 | have been broken down so that they can fit onto a page. | |
922fbb7b AC |
25392 | |
25393 | @smallexample | |
594fe323 | 25394 | (gdb) |
a2c02241 NR |
25395 | -target-download |
25396 | +download,@{section=".text",section-size="6668",total-size="9880"@} | |
25397 | +download,@{section=".text",section-sent="512",section-size="6668", | |
25398 | total-sent="512",total-size="9880"@} | |
25399 | +download,@{section=".text",section-sent="1024",section-size="6668", | |
25400 | total-sent="1024",total-size="9880"@} | |
25401 | +download,@{section=".text",section-sent="1536",section-size="6668", | |
25402 | total-sent="1536",total-size="9880"@} | |
25403 | +download,@{section=".text",section-sent="2048",section-size="6668", | |
25404 | total-sent="2048",total-size="9880"@} | |
25405 | +download,@{section=".text",section-sent="2560",section-size="6668", | |
25406 | total-sent="2560",total-size="9880"@} | |
25407 | +download,@{section=".text",section-sent="3072",section-size="6668", | |
25408 | total-sent="3072",total-size="9880"@} | |
25409 | +download,@{section=".text",section-sent="3584",section-size="6668", | |
25410 | total-sent="3584",total-size="9880"@} | |
25411 | +download,@{section=".text",section-sent="4096",section-size="6668", | |
25412 | total-sent="4096",total-size="9880"@} | |
25413 | +download,@{section=".text",section-sent="4608",section-size="6668", | |
25414 | total-sent="4608",total-size="9880"@} | |
25415 | +download,@{section=".text",section-sent="5120",section-size="6668", | |
25416 | total-sent="5120",total-size="9880"@} | |
25417 | +download,@{section=".text",section-sent="5632",section-size="6668", | |
25418 | total-sent="5632",total-size="9880"@} | |
25419 | +download,@{section=".text",section-sent="6144",section-size="6668", | |
25420 | total-sent="6144",total-size="9880"@} | |
25421 | +download,@{section=".text",section-sent="6656",section-size="6668", | |
25422 | total-sent="6656",total-size="9880"@} | |
25423 | +download,@{section=".init",section-size="28",total-size="9880"@} | |
25424 | +download,@{section=".fini",section-size="28",total-size="9880"@} | |
25425 | +download,@{section=".data",section-size="3156",total-size="9880"@} | |
25426 | +download,@{section=".data",section-sent="512",section-size="3156", | |
25427 | total-sent="7236",total-size="9880"@} | |
25428 | +download,@{section=".data",section-sent="1024",section-size="3156", | |
25429 | total-sent="7748",total-size="9880"@} | |
25430 | +download,@{section=".data",section-sent="1536",section-size="3156", | |
25431 | total-sent="8260",total-size="9880"@} | |
25432 | +download,@{section=".data",section-sent="2048",section-size="3156", | |
25433 | total-sent="8772",total-size="9880"@} | |
25434 | +download,@{section=".data",section-sent="2560",section-size="3156", | |
25435 | total-sent="9284",total-size="9880"@} | |
25436 | +download,@{section=".data",section-sent="3072",section-size="3156", | |
25437 | total-sent="9796",total-size="9880"@} | |
25438 | ^done,address="0x10004",load-size="9880",transfer-rate="6586", | |
25439 | write-rate="429" | |
594fe323 | 25440 | (gdb) |
922fbb7b AC |
25441 | @end smallexample |
25442 | ||
25443 | ||
9901a55b | 25444 | @ignore |
a2c02241 NR |
25445 | @subheading The @code{-target-exec-status} Command |
25446 | @findex -target-exec-status | |
922fbb7b AC |
25447 | |
25448 | @subsubheading Synopsis | |
25449 | ||
25450 | @smallexample | |
a2c02241 | 25451 | -target-exec-status |
922fbb7b AC |
25452 | @end smallexample |
25453 | ||
a2c02241 NR |
25454 | Provide information on the state of the target (whether it is running or |
25455 | not, for instance). | |
922fbb7b | 25456 | |
a2c02241 | 25457 | @subsubheading @value{GDBN} Command |
922fbb7b | 25458 | |
a2c02241 NR |
25459 | There's no equivalent @value{GDBN} command. |
25460 | ||
25461 | @subsubheading Example | |
25462 | N.A. | |
922fbb7b | 25463 | |
a2c02241 NR |
25464 | |
25465 | @subheading The @code{-target-list-available-targets} Command | |
25466 | @findex -target-list-available-targets | |
922fbb7b AC |
25467 | |
25468 | @subsubheading Synopsis | |
25469 | ||
25470 | @smallexample | |
a2c02241 | 25471 | -target-list-available-targets |
922fbb7b AC |
25472 | @end smallexample |
25473 | ||
a2c02241 | 25474 | List the possible targets to connect to. |
922fbb7b | 25475 | |
a2c02241 | 25476 | @subsubheading @value{GDBN} Command |
922fbb7b | 25477 | |
a2c02241 | 25478 | The corresponding @value{GDBN} command is @samp{help target}. |
922fbb7b | 25479 | |
a2c02241 NR |
25480 | @subsubheading Example |
25481 | N.A. | |
25482 | ||
25483 | ||
25484 | @subheading The @code{-target-list-current-targets} Command | |
25485 | @findex -target-list-current-targets | |
922fbb7b AC |
25486 | |
25487 | @subsubheading Synopsis | |
25488 | ||
25489 | @smallexample | |
a2c02241 | 25490 | -target-list-current-targets |
922fbb7b AC |
25491 | @end smallexample |
25492 | ||
a2c02241 | 25493 | Describe the current target. |
922fbb7b | 25494 | |
a2c02241 | 25495 | @subsubheading @value{GDBN} Command |
922fbb7b | 25496 | |
a2c02241 NR |
25497 | The corresponding information is printed by @samp{info file} (among |
25498 | other things). | |
922fbb7b | 25499 | |
a2c02241 NR |
25500 | @subsubheading Example |
25501 | N.A. | |
25502 | ||
25503 | ||
25504 | @subheading The @code{-target-list-parameters} Command | |
25505 | @findex -target-list-parameters | |
922fbb7b AC |
25506 | |
25507 | @subsubheading Synopsis | |
25508 | ||
25509 | @smallexample | |
a2c02241 | 25510 | -target-list-parameters |
922fbb7b AC |
25511 | @end smallexample |
25512 | ||
a2c02241 | 25513 | @c ???? |
9901a55b | 25514 | @end ignore |
a2c02241 NR |
25515 | |
25516 | @subsubheading @value{GDBN} Command | |
25517 | ||
25518 | No equivalent. | |
922fbb7b AC |
25519 | |
25520 | @subsubheading Example | |
a2c02241 NR |
25521 | N.A. |
25522 | ||
25523 | ||
25524 | @subheading The @code{-target-select} Command | |
25525 | @findex -target-select | |
25526 | ||
25527 | @subsubheading Synopsis | |
922fbb7b AC |
25528 | |
25529 | @smallexample | |
a2c02241 | 25530 | -target-select @var{type} @var{parameters @dots{}} |
922fbb7b AC |
25531 | @end smallexample |
25532 | ||
a2c02241 | 25533 | Connect @value{GDBN} to the remote target. This command takes two args: |
922fbb7b | 25534 | |
a2c02241 NR |
25535 | @table @samp |
25536 | @item @var{type} | |
75c99385 | 25537 | The type of target, for instance @samp{remote}, etc. |
a2c02241 NR |
25538 | @item @var{parameters} |
25539 | Device names, host names and the like. @xref{Target Commands, , | |
79a6e687 | 25540 | Commands for Managing Targets}, for more details. |
a2c02241 NR |
25541 | @end table |
25542 | ||
25543 | The output is a connection notification, followed by the address at | |
25544 | which the target program is, in the following form: | |
922fbb7b AC |
25545 | |
25546 | @smallexample | |
a2c02241 NR |
25547 | ^connected,addr="@var{address}",func="@var{function name}", |
25548 | args=[@var{arg list}] | |
922fbb7b AC |
25549 | @end smallexample |
25550 | ||
a2c02241 NR |
25551 | @subsubheading @value{GDBN} Command |
25552 | ||
25553 | The corresponding @value{GDBN} command is @samp{target}. | |
265eeb58 NR |
25554 | |
25555 | @subsubheading Example | |
922fbb7b | 25556 | |
265eeb58 | 25557 | @smallexample |
594fe323 | 25558 | (gdb) |
75c99385 | 25559 | -target-select remote /dev/ttya |
a2c02241 | 25560 | ^connected,addr="0xfe00a300",func="??",args=[] |
594fe323 | 25561 | (gdb) |
265eeb58 | 25562 | @end smallexample |
ef21caaf | 25563 | |
a6b151f1 DJ |
25564 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25565 | @node GDB/MI File Transfer Commands | |
25566 | @section @sc{gdb/mi} File Transfer Commands | |
25567 | ||
25568 | ||
25569 | @subheading The @code{-target-file-put} Command | |
25570 | @findex -target-file-put | |
25571 | ||
25572 | @subsubheading Synopsis | |
25573 | ||
25574 | @smallexample | |
25575 | -target-file-put @var{hostfile} @var{targetfile} | |
25576 | @end smallexample | |
25577 | ||
25578 | Copy file @var{hostfile} from the host system (the machine running | |
25579 | @value{GDBN}) to @var{targetfile} on the target system. | |
25580 | ||
25581 | @subsubheading @value{GDBN} Command | |
25582 | ||
25583 | The corresponding @value{GDBN} command is @samp{remote put}. | |
25584 | ||
25585 | @subsubheading Example | |
25586 | ||
25587 | @smallexample | |
25588 | (gdb) | |
25589 | -target-file-put localfile remotefile | |
25590 | ^done | |
25591 | (gdb) | |
25592 | @end smallexample | |
25593 | ||
25594 | ||
1763a388 | 25595 | @subheading The @code{-target-file-get} Command |
a6b151f1 DJ |
25596 | @findex -target-file-get |
25597 | ||
25598 | @subsubheading Synopsis | |
25599 | ||
25600 | @smallexample | |
25601 | -target-file-get @var{targetfile} @var{hostfile} | |
25602 | @end smallexample | |
25603 | ||
25604 | Copy file @var{targetfile} from the target system to @var{hostfile} | |
25605 | on the host system. | |
25606 | ||
25607 | @subsubheading @value{GDBN} Command | |
25608 | ||
25609 | The corresponding @value{GDBN} command is @samp{remote get}. | |
25610 | ||
25611 | @subsubheading Example | |
25612 | ||
25613 | @smallexample | |
25614 | (gdb) | |
25615 | -target-file-get remotefile localfile | |
25616 | ^done | |
25617 | (gdb) | |
25618 | @end smallexample | |
25619 | ||
25620 | ||
25621 | @subheading The @code{-target-file-delete} Command | |
25622 | @findex -target-file-delete | |
25623 | ||
25624 | @subsubheading Synopsis | |
25625 | ||
25626 | @smallexample | |
25627 | -target-file-delete @var{targetfile} | |
25628 | @end smallexample | |
25629 | ||
25630 | Delete @var{targetfile} from the target system. | |
25631 | ||
25632 | @subsubheading @value{GDBN} Command | |
25633 | ||
25634 | The corresponding @value{GDBN} command is @samp{remote delete}. | |
25635 | ||
25636 | @subsubheading Example | |
25637 | ||
25638 | @smallexample | |
25639 | (gdb) | |
25640 | -target-file-delete remotefile | |
25641 | ^done | |
25642 | (gdb) | |
25643 | @end smallexample | |
25644 | ||
25645 | ||
ef21caaf NR |
25646 | @c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
25647 | @node GDB/MI Miscellaneous Commands | |
25648 | @section Miscellaneous @sc{gdb/mi} Commands | |
25649 | ||
25650 | @c @subheading -gdb-complete | |
25651 | ||
25652 | @subheading The @code{-gdb-exit} Command | |
25653 | @findex -gdb-exit | |
25654 | ||
25655 | @subsubheading Synopsis | |
25656 | ||
25657 | @smallexample | |
25658 | -gdb-exit | |
25659 | @end smallexample | |
25660 | ||
25661 | Exit @value{GDBN} immediately. | |
25662 | ||
25663 | @subsubheading @value{GDBN} Command | |
25664 | ||
25665 | Approximately corresponds to @samp{quit}. | |
25666 | ||
25667 | @subsubheading Example | |
25668 | ||
25669 | @smallexample | |
594fe323 | 25670 | (gdb) |
ef21caaf NR |
25671 | -gdb-exit |
25672 | ^exit | |
25673 | @end smallexample | |
25674 | ||
a2c02241 | 25675 | |
9901a55b | 25676 | @ignore |
a2c02241 NR |
25677 | @subheading The @code{-exec-abort} Command |
25678 | @findex -exec-abort | |
25679 | ||
25680 | @subsubheading Synopsis | |
25681 | ||
25682 | @smallexample | |
25683 | -exec-abort | |
25684 | @end smallexample | |
25685 | ||
25686 | Kill the inferior running program. | |
25687 | ||
25688 | @subsubheading @value{GDBN} Command | |
25689 | ||
25690 | The corresponding @value{GDBN} command is @samp{kill}. | |
25691 | ||
25692 | @subsubheading Example | |
25693 | N.A. | |
9901a55b | 25694 | @end ignore |
a2c02241 NR |
25695 | |
25696 | ||
ef21caaf NR |
25697 | @subheading The @code{-gdb-set} Command |
25698 | @findex -gdb-set | |
25699 | ||
25700 | @subsubheading Synopsis | |
25701 | ||
25702 | @smallexample | |
25703 | -gdb-set | |
25704 | @end smallexample | |
25705 | ||
25706 | Set an internal @value{GDBN} variable. | |
25707 | @c IS THIS A DOLLAR VARIABLE? OR SOMETHING LIKE ANNOTATE ????? | |
25708 | ||
25709 | @subsubheading @value{GDBN} Command | |
25710 | ||
25711 | The corresponding @value{GDBN} command is @samp{set}. | |
25712 | ||
25713 | @subsubheading Example | |
25714 | ||
25715 | @smallexample | |
594fe323 | 25716 | (gdb) |
ef21caaf NR |
25717 | -gdb-set $foo=3 |
25718 | ^done | |
594fe323 | 25719 | (gdb) |
ef21caaf NR |
25720 | @end smallexample |
25721 | ||
25722 | ||
25723 | @subheading The @code{-gdb-show} Command | |
25724 | @findex -gdb-show | |
25725 | ||
25726 | @subsubheading Synopsis | |
25727 | ||
25728 | @smallexample | |
25729 | -gdb-show | |
25730 | @end smallexample | |
25731 | ||
25732 | Show the current value of a @value{GDBN} variable. | |
25733 | ||
79a6e687 | 25734 | @subsubheading @value{GDBN} Command |
ef21caaf NR |
25735 | |
25736 | The corresponding @value{GDBN} command is @samp{show}. | |
25737 | ||
25738 | @subsubheading Example | |
25739 | ||
25740 | @smallexample | |
594fe323 | 25741 | (gdb) |
ef21caaf NR |
25742 | -gdb-show annotate |
25743 | ^done,value="0" | |
594fe323 | 25744 | (gdb) |
ef21caaf NR |
25745 | @end smallexample |
25746 | ||
25747 | @c @subheading -gdb-source | |
25748 | ||
25749 | ||
25750 | @subheading The @code{-gdb-version} Command | |
25751 | @findex -gdb-version | |
25752 | ||
25753 | @subsubheading Synopsis | |
25754 | ||
25755 | @smallexample | |
25756 | -gdb-version | |
25757 | @end smallexample | |
25758 | ||
25759 | Show version information for @value{GDBN}. Used mostly in testing. | |
25760 | ||
25761 | @subsubheading @value{GDBN} Command | |
25762 | ||
25763 | The @value{GDBN} equivalent is @samp{show version}. @value{GDBN} by | |
25764 | default shows this information when you start an interactive session. | |
25765 | ||
25766 | @subsubheading Example | |
25767 | ||
25768 | @c This example modifies the actual output from GDB to avoid overfull | |
25769 | @c box in TeX. | |
25770 | @smallexample | |
594fe323 | 25771 | (gdb) |
ef21caaf NR |
25772 | -gdb-version |
25773 | ~GNU gdb 5.2.1 | |
25774 | ~Copyright 2000 Free Software Foundation, Inc. | |
25775 | ~GDB is free software, covered by the GNU General Public License, and | |
25776 | ~you are welcome to change it and/or distribute copies of it under | |
25777 | ~ certain conditions. | |
25778 | ~Type "show copying" to see the conditions. | |
25779 | ~There is absolutely no warranty for GDB. Type "show warranty" for | |
25780 | ~ details. | |
25781 | ~This GDB was configured as | |
25782 | "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi". | |
25783 | ^done | |
594fe323 | 25784 | (gdb) |
ef21caaf NR |
25785 | @end smallexample |
25786 | ||
084344da VP |
25787 | @subheading The @code{-list-features} Command |
25788 | @findex -list-features | |
25789 | ||
25790 | Returns a list of particular features of the MI protocol that | |
25791 | this version of gdb implements. A feature can be a command, | |
25792 | or a new field in an output of some command, or even an | |
25793 | important bugfix. While a frontend can sometimes detect presence | |
25794 | of a feature at runtime, it is easier to perform detection at debugger | |
25795 | startup. | |
25796 | ||
25797 | The command returns a list of strings, with each string naming an | |
25798 | available feature. Each returned string is just a name, it does not | |
25799 | have any internal structure. The list of possible feature names | |
25800 | is given below. | |
25801 | ||
25802 | Example output: | |
25803 | ||
25804 | @smallexample | |
25805 | (gdb) -list-features | |
25806 | ^done,result=["feature1","feature2"] | |
25807 | @end smallexample | |
25808 | ||
25809 | The current list of features is: | |
25810 | ||
30e026bb VP |
25811 | @table @samp |
25812 | @item frozen-varobjs | |
25813 | Indicates presence of the @code{-var-set-frozen} command, as well | |
25814 | as possible presense of the @code{frozen} field in the output | |
25815 | of @code{-varobj-create}. | |
25816 | @item pending-breakpoints | |
25817 | Indicates presence of the @option{-f} option to the @code{-break-insert} command. | |
b6313243 TT |
25818 | @item python |
25819 | Indicates presence of Python scripting support, Python-based | |
25820 | pretty-printing commands, and possible presence of the | |
25821 | @samp{display_hint} field in the output of @code{-var-list-children} | |
30e026bb VP |
25822 | @item thread-info |
25823 | Indicates presence of the @code{-thread-info} command. | |
8b4ed427 | 25824 | |
30e026bb | 25825 | @end table |
084344da | 25826 | |
c6ebd6cf VP |
25827 | @subheading The @code{-list-target-features} Command |
25828 | @findex -list-target-features | |
25829 | ||
25830 | Returns a list of particular features that are supported by the | |
25831 | target. Those features affect the permitted MI commands, but | |
25832 | unlike the features reported by the @code{-list-features} command, the | |
25833 | features depend on which target GDB is using at the moment. Whenever | |
25834 | a target can change, due to commands such as @code{-target-select}, | |
25835 | @code{-target-attach} or @code{-exec-run}, the list of target features | |
25836 | may change, and the frontend should obtain it again. | |
25837 | Example output: | |
25838 | ||
25839 | @smallexample | |
25840 | (gdb) -list-features | |
25841 | ^done,result=["async"] | |
25842 | @end smallexample | |
25843 | ||
25844 | The current list of features is: | |
25845 | ||
25846 | @table @samp | |
25847 | @item async | |
25848 | Indicates that the target is capable of asynchronous command | |
25849 | execution, which means that @value{GDBN} will accept further commands | |
25850 | while the target is running. | |
25851 | ||
25852 | @end table | |
25853 | ||
c3b108f7 VP |
25854 | @subheading The @code{-list-thread-groups} Command |
25855 | @findex -list-thread-groups | |
25856 | ||
25857 | @subheading Synopsis | |
25858 | ||
25859 | @smallexample | |
25860 | -list-thread-groups [ --available ] [ @var{group} ] | |
25861 | @end smallexample | |
25862 | ||
25863 | When used without the @var{group} parameter, lists top-level thread | |
25864 | groups that are being debugged. When used with the @var{group} | |
25865 | parameter, the children of the specified group are listed. The | |
25866 | children can be either threads, or other groups. At present, | |
25867 | @value{GDBN} will not report both threads and groups as children at | |
25868 | the same time, but it may change in future. | |
25869 | ||
25870 | With the @samp{--available} option, instead of reporting groups that | |
25871 | are been debugged, GDB will report all thread groups available on the | |
25872 | target. Using the @samp{--available} option together with @var{group} | |
25873 | is not allowed. | |
25874 | ||
25875 | @subheading Example | |
25876 | ||
25877 | @smallexample | |
25878 | @value{GDBP} | |
25879 | -list-thread-groups | |
25880 | ^done,groups=[@{id="17",type="process",pid="yyy",num_children="2"@}] | |
25881 | -list-thread-groups 17 | |
25882 | ^done,threads=[@{id="2",target-id="Thread 0xb7e14b90 (LWP 21257)", | |
25883 | frame=@{level="0",addr="0xffffe410",func="__kernel_vsyscall",args=[]@},state="running"@}, | |
25884 | @{id="1",target-id="Thread 0xb7e156b0 (LWP 21254)", | |
25885 | frame=@{level="0",addr="0x0804891f",func="foo",args=[@{name="i",value="10"@}], | |
25886 | file="/tmp/a.c",fullname="/tmp/a.c",line="158"@},state="running"@}]] | |
25887 | @end smallexample | |
c6ebd6cf | 25888 | |
ef21caaf NR |
25889 | @subheading The @code{-interpreter-exec} Command |
25890 | @findex -interpreter-exec | |
25891 | ||
25892 | @subheading Synopsis | |
25893 | ||
25894 | @smallexample | |
25895 | -interpreter-exec @var{interpreter} @var{command} | |
25896 | @end smallexample | |
a2c02241 | 25897 | @anchor{-interpreter-exec} |
ef21caaf NR |
25898 | |
25899 | Execute the specified @var{command} in the given @var{interpreter}. | |
25900 | ||
25901 | @subheading @value{GDBN} Command | |
25902 | ||
25903 | The corresponding @value{GDBN} command is @samp{interpreter-exec}. | |
25904 | ||
25905 | @subheading Example | |
25906 | ||
25907 | @smallexample | |
594fe323 | 25908 | (gdb) |
ef21caaf NR |
25909 | -interpreter-exec console "break main" |
25910 | &"During symbol reading, couldn't parse type; debugger out of date?.\n" | |
25911 | &"During symbol reading, bad structure-type format.\n" | |
25912 | ~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n" | |
25913 | ^done | |
594fe323 | 25914 | (gdb) |
ef21caaf NR |
25915 | @end smallexample |
25916 | ||
25917 | @subheading The @code{-inferior-tty-set} Command | |
25918 | @findex -inferior-tty-set | |
25919 | ||
25920 | @subheading Synopsis | |
25921 | ||
25922 | @smallexample | |
25923 | -inferior-tty-set /dev/pts/1 | |
25924 | @end smallexample | |
25925 | ||
25926 | Set terminal for future runs of the program being debugged. | |
25927 | ||
25928 | @subheading @value{GDBN} Command | |
25929 | ||
25930 | The corresponding @value{GDBN} command is @samp{set inferior-tty} /dev/pts/1. | |
25931 | ||
25932 | @subheading Example | |
25933 | ||
25934 | @smallexample | |
594fe323 | 25935 | (gdb) |
ef21caaf NR |
25936 | -inferior-tty-set /dev/pts/1 |
25937 | ^done | |
594fe323 | 25938 | (gdb) |
ef21caaf NR |
25939 | @end smallexample |
25940 | ||
25941 | @subheading The @code{-inferior-tty-show} Command | |
25942 | @findex -inferior-tty-show | |
25943 | ||
25944 | @subheading Synopsis | |
25945 | ||
25946 | @smallexample | |
25947 | -inferior-tty-show | |
25948 | @end smallexample | |
25949 | ||
25950 | Show terminal for future runs of program being debugged. | |
25951 | ||
25952 | @subheading @value{GDBN} Command | |
25953 | ||
25954 | The corresponding @value{GDBN} command is @samp{show inferior-tty}. | |
25955 | ||
25956 | @subheading Example | |
25957 | ||
25958 | @smallexample | |
594fe323 | 25959 | (gdb) |
ef21caaf NR |
25960 | -inferior-tty-set /dev/pts/1 |
25961 | ^done | |
594fe323 | 25962 | (gdb) |
ef21caaf NR |
25963 | -inferior-tty-show |
25964 | ^done,inferior_tty_terminal="/dev/pts/1" | |
594fe323 | 25965 | (gdb) |
ef21caaf | 25966 | @end smallexample |
922fbb7b | 25967 | |
a4eefcd8 NR |
25968 | @subheading The @code{-enable-timings} Command |
25969 | @findex -enable-timings | |
25970 | ||
25971 | @subheading Synopsis | |
25972 | ||
25973 | @smallexample | |
25974 | -enable-timings [yes | no] | |
25975 | @end smallexample | |
25976 | ||
25977 | Toggle the printing of the wallclock, user and system times for an MI | |
25978 | command as a field in its output. This command is to help frontend | |
25979 | developers optimize the performance of their code. No argument is | |
25980 | equivalent to @samp{yes}. | |
25981 | ||
25982 | @subheading @value{GDBN} Command | |
25983 | ||
25984 | No equivalent. | |
25985 | ||
25986 | @subheading Example | |
25987 | ||
25988 | @smallexample | |
25989 | (gdb) | |
25990 | -enable-timings | |
25991 | ^done | |
25992 | (gdb) | |
25993 | -break-insert main | |
25994 | ^done,bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y", | |
25995 | addr="0x080484ed",func="main",file="myprog.c", | |
25996 | fullname="/home/nickrob/myprog.c",line="73",times="0"@}, | |
25997 | time=@{wallclock="0.05185",user="0.00800",system="0.00000"@} | |
25998 | (gdb) | |
25999 | -enable-timings no | |
26000 | ^done | |
26001 | (gdb) | |
26002 | -exec-run | |
26003 | ^running | |
26004 | (gdb) | |
a47ec5fe | 26005 | *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",thread-id="0", |
a4eefcd8 NR |
26006 | frame=@{addr="0x080484ed",func="main",args=[@{name="argc",value="1"@}, |
26007 | @{name="argv",value="0xbfb60364"@}],file="myprog.c", | |
26008 | fullname="/home/nickrob/myprog.c",line="73"@} | |
26009 | (gdb) | |
26010 | @end smallexample | |
26011 | ||
922fbb7b AC |
26012 | @node Annotations |
26013 | @chapter @value{GDBN} Annotations | |
26014 | ||
086432e2 AC |
26015 | This chapter describes annotations in @value{GDBN}. Annotations were |
26016 | designed to interface @value{GDBN} to graphical user interfaces or other | |
26017 | similar programs which want to interact with @value{GDBN} at a | |
922fbb7b AC |
26018 | relatively high level. |
26019 | ||
d3e8051b | 26020 | The annotation mechanism has largely been superseded by @sc{gdb/mi} |
086432e2 AC |
26021 | (@pxref{GDB/MI}). |
26022 | ||
922fbb7b AC |
26023 | @ignore |
26024 | This is Edition @value{EDITION}, @value{DATE}. | |
26025 | @end ignore | |
26026 | ||
26027 | @menu | |
26028 | * Annotations Overview:: What annotations are; the general syntax. | |
9e6c4bd5 | 26029 | * Server Prefix:: Issuing a command without affecting user state. |
922fbb7b AC |
26030 | * Prompting:: Annotations marking @value{GDBN}'s need for input. |
26031 | * Errors:: Annotations for error messages. | |
922fbb7b AC |
26032 | * Invalidation:: Some annotations describe things now invalid. |
26033 | * Annotations for Running:: | |
26034 | Whether the program is running, how it stopped, etc. | |
26035 | * Source Annotations:: Annotations describing source code. | |
922fbb7b AC |
26036 | @end menu |
26037 | ||
26038 | @node Annotations Overview | |
26039 | @section What is an Annotation? | |
26040 | @cindex annotations | |
26041 | ||
922fbb7b AC |
26042 | Annotations start with a newline character, two @samp{control-z} |
26043 | characters, and the name of the annotation. If there is no additional | |
26044 | information associated with this annotation, the name of the annotation | |
26045 | is followed immediately by a newline. If there is additional | |
26046 | information, the name of the annotation is followed by a space, the | |
26047 | additional information, and a newline. The additional information | |
26048 | cannot contain newline characters. | |
26049 | ||
26050 | Any output not beginning with a newline and two @samp{control-z} | |
26051 | characters denotes literal output from @value{GDBN}. Currently there is | |
26052 | no need for @value{GDBN} to output a newline followed by two | |
26053 | @samp{control-z} characters, but if there was such a need, the | |
26054 | annotations could be extended with an @samp{escape} annotation which | |
26055 | means those three characters as output. | |
26056 | ||
086432e2 AC |
26057 | The annotation @var{level}, which is specified using the |
26058 | @option{--annotate} command line option (@pxref{Mode Options}), controls | |
26059 | how much information @value{GDBN} prints together with its prompt, | |
26060 | values of expressions, source lines, and other types of output. Level 0 | |
d3e8051b | 26061 | is for no annotations, level 1 is for use when @value{GDBN} is run as a |
086432e2 AC |
26062 | subprocess of @sc{gnu} Emacs, level 3 is the maximum annotation suitable |
26063 | for programs that control @value{GDBN}, and level 2 annotations have | |
26064 | been made obsolete (@pxref{Limitations, , Limitations of the Annotation | |
09d4efe1 EZ |
26065 | Interface, annotate, GDB's Obsolete Annotations}). |
26066 | ||
26067 | @table @code | |
26068 | @kindex set annotate | |
26069 | @item set annotate @var{level} | |
e09f16f9 | 26070 | The @value{GDBN} command @code{set annotate} sets the level of |
09d4efe1 | 26071 | annotations to the specified @var{level}. |
9c16f35a EZ |
26072 | |
26073 | @item show annotate | |
26074 | @kindex show annotate | |
26075 | Show the current annotation level. | |
09d4efe1 EZ |
26076 | @end table |
26077 | ||
26078 | This chapter describes level 3 annotations. | |
086432e2 | 26079 | |
922fbb7b AC |
26080 | A simple example of starting up @value{GDBN} with annotations is: |
26081 | ||
26082 | @smallexample | |
086432e2 AC |
26083 | $ @kbd{gdb --annotate=3} |
26084 | GNU gdb 6.0 | |
26085 | Copyright 2003 Free Software Foundation, Inc. | |
922fbb7b AC |
26086 | GDB is free software, covered by the GNU General Public License, |
26087 | and you are welcome to change it and/or distribute copies of it | |
26088 | under certain conditions. | |
26089 | Type "show copying" to see the conditions. | |
26090 | There is absolutely no warranty for GDB. Type "show warranty" | |
26091 | for details. | |
086432e2 | 26092 | This GDB was configured as "i386-pc-linux-gnu" |
922fbb7b AC |
26093 | |
26094 | ^Z^Zpre-prompt | |
f7dc1244 | 26095 | (@value{GDBP}) |
922fbb7b | 26096 | ^Z^Zprompt |
086432e2 | 26097 | @kbd{quit} |
922fbb7b AC |
26098 | |
26099 | ^Z^Zpost-prompt | |
b383017d | 26100 | $ |
922fbb7b AC |
26101 | @end smallexample |
26102 | ||
26103 | Here @samp{quit} is input to @value{GDBN}; the rest is output from | |
26104 | @value{GDBN}. The three lines beginning @samp{^Z^Z} (where @samp{^Z} | |
26105 | denotes a @samp{control-z} character) are annotations; the rest is | |
26106 | output from @value{GDBN}. | |
26107 | ||
9e6c4bd5 NR |
26108 | @node Server Prefix |
26109 | @section The Server Prefix | |
26110 | @cindex server prefix | |
26111 | ||
26112 | If you prefix a command with @samp{server } then it will not affect | |
26113 | the command history, nor will it affect @value{GDBN}'s notion of which | |
26114 | command to repeat if @key{RET} is pressed on a line by itself. This | |
26115 | means that commands can be run behind a user's back by a front-end in | |
26116 | a transparent manner. | |
26117 | ||
d837706a NR |
26118 | The @code{server } prefix does not affect the recording of values into |
26119 | the value history; to print a value without recording it into the | |
26120 | value history, use the @code{output} command instead of the | |
26121 | @code{print} command. | |
26122 | ||
26123 | Using this prefix also disables confirmation requests | |
26124 | (@pxref{confirmation requests}). | |
9e6c4bd5 | 26125 | |
922fbb7b AC |
26126 | @node Prompting |
26127 | @section Annotation for @value{GDBN} Input | |
26128 | ||
26129 | @cindex annotations for prompts | |
26130 | When @value{GDBN} prompts for input, it annotates this fact so it is possible | |
26131 | to know when to send output, when the output from a given command is | |
26132 | over, etc. | |
26133 | ||
26134 | Different kinds of input each have a different @dfn{input type}. Each | |
26135 | input type has three annotations: a @code{pre-} annotation, which | |
26136 | denotes the beginning of any prompt which is being output, a plain | |
26137 | annotation, which denotes the end of the prompt, and then a @code{post-} | |
26138 | annotation which denotes the end of any echo which may (or may not) be | |
26139 | associated with the input. For example, the @code{prompt} input type | |
26140 | features the following annotations: | |
26141 | ||
26142 | @smallexample | |
26143 | ^Z^Zpre-prompt | |
26144 | ^Z^Zprompt | |
26145 | ^Z^Zpost-prompt | |
26146 | @end smallexample | |
26147 | ||
26148 | The input types are | |
26149 | ||
26150 | @table @code | |
e5ac9b53 EZ |
26151 | @findex pre-prompt annotation |
26152 | @findex prompt annotation | |
26153 | @findex post-prompt annotation | |
922fbb7b AC |
26154 | @item prompt |
26155 | When @value{GDBN} is prompting for a command (the main @value{GDBN} prompt). | |
26156 | ||
e5ac9b53 EZ |
26157 | @findex pre-commands annotation |
26158 | @findex commands annotation | |
26159 | @findex post-commands annotation | |
922fbb7b AC |
26160 | @item commands |
26161 | When @value{GDBN} prompts for a set of commands, like in the @code{commands} | |
26162 | command. The annotations are repeated for each command which is input. | |
26163 | ||
e5ac9b53 EZ |
26164 | @findex pre-overload-choice annotation |
26165 | @findex overload-choice annotation | |
26166 | @findex post-overload-choice annotation | |
922fbb7b AC |
26167 | @item overload-choice |
26168 | When @value{GDBN} wants the user to select between various overloaded functions. | |
26169 | ||
e5ac9b53 EZ |
26170 | @findex pre-query annotation |
26171 | @findex query annotation | |
26172 | @findex post-query annotation | |
922fbb7b AC |
26173 | @item query |
26174 | When @value{GDBN} wants the user to confirm a potentially dangerous operation. | |
26175 | ||
e5ac9b53 EZ |
26176 | @findex pre-prompt-for-continue annotation |
26177 | @findex prompt-for-continue annotation | |
26178 | @findex post-prompt-for-continue annotation | |
922fbb7b AC |
26179 | @item prompt-for-continue |
26180 | When @value{GDBN} is asking the user to press return to continue. Note: Don't | |
26181 | expect this to work well; instead use @code{set height 0} to disable | |
26182 | prompting. This is because the counting of lines is buggy in the | |
26183 | presence of annotations. | |
26184 | @end table | |
26185 | ||
26186 | @node Errors | |
26187 | @section Errors | |
26188 | @cindex annotations for errors, warnings and interrupts | |
26189 | ||
e5ac9b53 | 26190 | @findex quit annotation |
922fbb7b AC |
26191 | @smallexample |
26192 | ^Z^Zquit | |
26193 | @end smallexample | |
26194 | ||
26195 | This annotation occurs right before @value{GDBN} responds to an interrupt. | |
26196 | ||
e5ac9b53 | 26197 | @findex error annotation |
922fbb7b AC |
26198 | @smallexample |
26199 | ^Z^Zerror | |
26200 | @end smallexample | |
26201 | ||
26202 | This annotation occurs right before @value{GDBN} responds to an error. | |
26203 | ||
26204 | Quit and error annotations indicate that any annotations which @value{GDBN} was | |
26205 | in the middle of may end abruptly. For example, if a | |
26206 | @code{value-history-begin} annotation is followed by a @code{error}, one | |
26207 | cannot expect to receive the matching @code{value-history-end}. One | |
26208 | cannot expect not to receive it either, however; an error annotation | |
26209 | does not necessarily mean that @value{GDBN} is immediately returning all the way | |
26210 | to the top level. | |
26211 | ||
e5ac9b53 | 26212 | @findex error-begin annotation |
922fbb7b AC |
26213 | A quit or error annotation may be preceded by |
26214 | ||
26215 | @smallexample | |
26216 | ^Z^Zerror-begin | |
26217 | @end smallexample | |
26218 | ||
26219 | Any output between that and the quit or error annotation is the error | |
26220 | message. | |
26221 | ||
26222 | Warning messages are not yet annotated. | |
26223 | @c If we want to change that, need to fix warning(), type_error(), | |
26224 | @c range_error(), and possibly other places. | |
26225 | ||
922fbb7b AC |
26226 | @node Invalidation |
26227 | @section Invalidation Notices | |
26228 | ||
26229 | @cindex annotations for invalidation messages | |
26230 | The following annotations say that certain pieces of state may have | |
26231 | changed. | |
26232 | ||
26233 | @table @code | |
e5ac9b53 | 26234 | @findex frames-invalid annotation |
922fbb7b AC |
26235 | @item ^Z^Zframes-invalid |
26236 | ||
26237 | The frames (for example, output from the @code{backtrace} command) may | |
26238 | have changed. | |
26239 | ||
e5ac9b53 | 26240 | @findex breakpoints-invalid annotation |
922fbb7b AC |
26241 | @item ^Z^Zbreakpoints-invalid |
26242 | ||
26243 | The breakpoints may have changed. For example, the user just added or | |
26244 | deleted a breakpoint. | |
26245 | @end table | |
26246 | ||
26247 | @node Annotations for Running | |
26248 | @section Running the Program | |
26249 | @cindex annotations for running programs | |
26250 | ||
e5ac9b53 EZ |
26251 | @findex starting annotation |
26252 | @findex stopping annotation | |
922fbb7b | 26253 | When the program starts executing due to a @value{GDBN} command such as |
b383017d | 26254 | @code{step} or @code{continue}, |
922fbb7b AC |
26255 | |
26256 | @smallexample | |
26257 | ^Z^Zstarting | |
26258 | @end smallexample | |
26259 | ||
b383017d | 26260 | is output. When the program stops, |
922fbb7b AC |
26261 | |
26262 | @smallexample | |
26263 | ^Z^Zstopped | |
26264 | @end smallexample | |
26265 | ||
26266 | is output. Before the @code{stopped} annotation, a variety of | |
26267 | annotations describe how the program stopped. | |
26268 | ||
26269 | @table @code | |
e5ac9b53 | 26270 | @findex exited annotation |
922fbb7b AC |
26271 | @item ^Z^Zexited @var{exit-status} |
26272 | The program exited, and @var{exit-status} is the exit status (zero for | |
26273 | successful exit, otherwise nonzero). | |
26274 | ||
e5ac9b53 EZ |
26275 | @findex signalled annotation |
26276 | @findex signal-name annotation | |
26277 | @findex signal-name-end annotation | |
26278 | @findex signal-string annotation | |
26279 | @findex signal-string-end annotation | |
922fbb7b AC |
26280 | @item ^Z^Zsignalled |
26281 | The program exited with a signal. After the @code{^Z^Zsignalled}, the | |
26282 | annotation continues: | |
26283 | ||
26284 | @smallexample | |
26285 | @var{intro-text} | |
26286 | ^Z^Zsignal-name | |
26287 | @var{name} | |
26288 | ^Z^Zsignal-name-end | |
26289 | @var{middle-text} | |
26290 | ^Z^Zsignal-string | |
26291 | @var{string} | |
26292 | ^Z^Zsignal-string-end | |
26293 | @var{end-text} | |
26294 | @end smallexample | |
26295 | ||
26296 | @noindent | |
26297 | where @var{name} is the name of the signal, such as @code{SIGILL} or | |
26298 | @code{SIGSEGV}, and @var{string} is the explanation of the signal, such | |
26299 | as @code{Illegal Instruction} or @code{Segmentation fault}. | |
26300 | @var{intro-text}, @var{middle-text}, and @var{end-text} are for the | |
26301 | user's benefit and have no particular format. | |
26302 | ||
e5ac9b53 | 26303 | @findex signal annotation |
922fbb7b AC |
26304 | @item ^Z^Zsignal |
26305 | The syntax of this annotation is just like @code{signalled}, but @value{GDBN} is | |
26306 | just saying that the program received the signal, not that it was | |
26307 | terminated with it. | |
26308 | ||
e5ac9b53 | 26309 | @findex breakpoint annotation |
922fbb7b AC |
26310 | @item ^Z^Zbreakpoint @var{number} |
26311 | The program hit breakpoint number @var{number}. | |
26312 | ||
e5ac9b53 | 26313 | @findex watchpoint annotation |
922fbb7b AC |
26314 | @item ^Z^Zwatchpoint @var{number} |
26315 | The program hit watchpoint number @var{number}. | |
26316 | @end table | |
26317 | ||
26318 | @node Source Annotations | |
26319 | @section Displaying Source | |
26320 | @cindex annotations for source display | |
26321 | ||
e5ac9b53 | 26322 | @findex source annotation |
922fbb7b AC |
26323 | The following annotation is used instead of displaying source code: |
26324 | ||
26325 | @smallexample | |
26326 | ^Z^Zsource @var{filename}:@var{line}:@var{character}:@var{middle}:@var{addr} | |
26327 | @end smallexample | |
26328 | ||
26329 | where @var{filename} is an absolute file name indicating which source | |
26330 | file, @var{line} is the line number within that file (where 1 is the | |
26331 | first line in the file), @var{character} is the character position | |
26332 | within the file (where 0 is the first character in the file) (for most | |
26333 | debug formats this will necessarily point to the beginning of a line), | |
26334 | @var{middle} is @samp{middle} if @var{addr} is in the middle of the | |
26335 | line, or @samp{beg} if @var{addr} is at the beginning of the line, and | |
26336 | @var{addr} is the address in the target program associated with the | |
26337 | source which is being displayed. @var{addr} is in the form @samp{0x} | |
26338 | followed by one or more lowercase hex digits (note that this does not | |
26339 | depend on the language). | |
26340 | ||
4efc6507 DE |
26341 | @node JIT Interface |
26342 | @chapter JIT Compilation Interface | |
26343 | @cindex just-in-time compilation | |
26344 | @cindex JIT compilation interface | |
26345 | ||
26346 | This chapter documents @value{GDBN}'s @dfn{just-in-time} (JIT) compilation | |
26347 | interface. A JIT compiler is a program or library that generates native | |
26348 | executable code at runtime and executes it, usually in order to achieve good | |
26349 | performance while maintaining platform independence. | |
26350 | ||
26351 | Programs that use JIT compilation are normally difficult to debug because | |
26352 | portions of their code are generated at runtime, instead of being loaded from | |
26353 | object files, which is where @value{GDBN} normally finds the program's symbols | |
26354 | and debug information. In order to debug programs that use JIT compilation, | |
26355 | @value{GDBN} has an interface that allows the program to register in-memory | |
26356 | symbol files with @value{GDBN} at runtime. | |
26357 | ||
26358 | If you are using @value{GDBN} to debug a program that uses this interface, then | |
26359 | it should work transparently so long as you have not stripped the binary. If | |
26360 | you are developing a JIT compiler, then the interface is documented in the rest | |
26361 | of this chapter. At this time, the only known client of this interface is the | |
26362 | LLVM JIT. | |
26363 | ||
26364 | Broadly speaking, the JIT interface mirrors the dynamic loader interface. The | |
26365 | JIT compiler communicates with @value{GDBN} by writing data into a global | |
26366 | variable and calling a fuction at a well-known symbol. When @value{GDBN} | |
26367 | attaches, it reads a linked list of symbol files from the global variable to | |
26368 | find existing code, and puts a breakpoint in the function so that it can find | |
26369 | out about additional code. | |
26370 | ||
26371 | @menu | |
26372 | * Declarations:: Relevant C struct declarations | |
26373 | * Registering Code:: Steps to register code | |
26374 | * Unregistering Code:: Steps to unregister code | |
26375 | @end menu | |
26376 | ||
26377 | @node Declarations | |
26378 | @section JIT Declarations | |
26379 | ||
26380 | These are the relevant struct declarations that a C program should include to | |
26381 | implement the interface: | |
26382 | ||
26383 | @smallexample | |
26384 | typedef enum | |
26385 | @{ | |
26386 | JIT_NOACTION = 0, | |
26387 | JIT_REGISTER_FN, | |
26388 | JIT_UNREGISTER_FN | |
26389 | @} jit_actions_t; | |
26390 | ||
26391 | struct jit_code_entry | |
26392 | @{ | |
26393 | struct jit_code_entry *next_entry; | |
26394 | struct jit_code_entry *prev_entry; | |
26395 | const char *symfile_addr; | |
26396 | uint64_t symfile_size; | |
26397 | @}; | |
26398 | ||
26399 | struct jit_descriptor | |
26400 | @{ | |
26401 | uint32_t version; | |
26402 | /* This type should be jit_actions_t, but we use uint32_t | |
26403 | to be explicit about the bitwidth. */ | |
26404 | uint32_t action_flag; | |
26405 | struct jit_code_entry *relevant_entry; | |
26406 | struct jit_code_entry *first_entry; | |
26407 | @}; | |
26408 | ||
26409 | /* GDB puts a breakpoint in this function. */ | |
26410 | void __attribute__((noinline)) __jit_debug_register_code() @{ @}; | |
26411 | ||
26412 | /* Make sure to specify the version statically, because the | |
26413 | debugger may check the version before we can set it. */ | |
26414 | struct jit_descriptor __jit_debug_descriptor = @{ 1, 0, 0, 0 @}; | |
26415 | @end smallexample | |
26416 | ||
26417 | If the JIT is multi-threaded, then it is important that the JIT synchronize any | |
26418 | modifications to this global data properly, which can easily be done by putting | |
26419 | a global mutex around modifications to these structures. | |
26420 | ||
26421 | @node Registering Code | |
26422 | @section Registering Code | |
26423 | ||
26424 | To register code with @value{GDBN}, the JIT should follow this protocol: | |
26425 | ||
26426 | @itemize @bullet | |
26427 | @item | |
26428 | Generate an object file in memory with symbols and other desired debug | |
26429 | information. The file must include the virtual addresses of the sections. | |
26430 | ||
26431 | @item | |
26432 | Create a code entry for the file, which gives the start and size of the symbol | |
26433 | file. | |
26434 | ||
26435 | @item | |
26436 | Add it to the linked list in the JIT descriptor. | |
26437 | ||
26438 | @item | |
26439 | Point the relevant_entry field of the descriptor at the entry. | |
26440 | ||
26441 | @item | |
26442 | Set @code{action_flag} to @code{JIT_REGISTER} and call | |
26443 | @code{__jit_debug_register_code}. | |
26444 | @end itemize | |
26445 | ||
26446 | When @value{GDBN} is attached and the breakpoint fires, @value{GDBN} uses the | |
26447 | @code{relevant_entry} pointer so it doesn't have to walk the list looking for | |
26448 | new code. However, the linked list must still be maintained in order to allow | |
26449 | @value{GDBN} to attach to a running process and still find the symbol files. | |
26450 | ||
26451 | @node Unregistering Code | |
26452 | @section Unregistering Code | |
26453 | ||
26454 | If code is freed, then the JIT should use the following protocol: | |
26455 | ||
26456 | @itemize @bullet | |
26457 | @item | |
26458 | Remove the code entry corresponding to the code from the linked list. | |
26459 | ||
26460 | @item | |
26461 | Point the @code{relevant_entry} field of the descriptor at the code entry. | |
26462 | ||
26463 | @item | |
26464 | Set @code{action_flag} to @code{JIT_UNREGISTER} and call | |
26465 | @code{__jit_debug_register_code}. | |
26466 | @end itemize | |
26467 | ||
26468 | If the JIT frees or recompiles code without unregistering it, then @value{GDBN} | |
26469 | and the JIT will leak the memory used for the associated symbol files. | |
26470 | ||
8e04817f AC |
26471 | @node GDB Bugs |
26472 | @chapter Reporting Bugs in @value{GDBN} | |
26473 | @cindex bugs in @value{GDBN} | |
26474 | @cindex reporting bugs in @value{GDBN} | |
c906108c | 26475 | |
8e04817f | 26476 | Your bug reports play an essential role in making @value{GDBN} reliable. |
c906108c | 26477 | |
8e04817f AC |
26478 | Reporting a bug may help you by bringing a solution to your problem, or it |
26479 | may not. But in any case the principal function of a bug report is to help | |
26480 | the entire community by making the next version of @value{GDBN} work better. Bug | |
26481 | reports are your contribution to the maintenance of @value{GDBN}. | |
c906108c | 26482 | |
8e04817f AC |
26483 | In order for a bug report to serve its purpose, you must include the |
26484 | information that enables us to fix the bug. | |
c4555f82 SC |
26485 | |
26486 | @menu | |
8e04817f AC |
26487 | * Bug Criteria:: Have you found a bug? |
26488 | * Bug Reporting:: How to report bugs | |
c4555f82 SC |
26489 | @end menu |
26490 | ||
8e04817f | 26491 | @node Bug Criteria |
79a6e687 | 26492 | @section Have You Found a Bug? |
8e04817f | 26493 | @cindex bug criteria |
c4555f82 | 26494 | |
8e04817f | 26495 | If you are not sure whether you have found a bug, here are some guidelines: |
c4555f82 SC |
26496 | |
26497 | @itemize @bullet | |
8e04817f AC |
26498 | @cindex fatal signal |
26499 | @cindex debugger crash | |
26500 | @cindex crash of debugger | |
c4555f82 | 26501 | @item |
8e04817f AC |
26502 | If the debugger gets a fatal signal, for any input whatever, that is a |
26503 | @value{GDBN} bug. Reliable debuggers never crash. | |
26504 | ||
26505 | @cindex error on valid input | |
26506 | @item | |
26507 | If @value{GDBN} produces an error message for valid input, that is a | |
26508 | bug. (Note that if you're cross debugging, the problem may also be | |
26509 | somewhere in the connection to the target.) | |
c4555f82 | 26510 | |
8e04817f | 26511 | @cindex invalid input |
c4555f82 | 26512 | @item |
8e04817f AC |
26513 | If @value{GDBN} does not produce an error message for invalid input, |
26514 | that is a bug. However, you should note that your idea of | |
26515 | ``invalid input'' might be our idea of ``an extension'' or ``support | |
26516 | for traditional practice''. | |
26517 | ||
26518 | @item | |
26519 | If you are an experienced user of debugging tools, your suggestions | |
26520 | for improvement of @value{GDBN} are welcome in any case. | |
c4555f82 SC |
26521 | @end itemize |
26522 | ||
8e04817f | 26523 | @node Bug Reporting |
79a6e687 | 26524 | @section How to Report Bugs |
8e04817f AC |
26525 | @cindex bug reports |
26526 | @cindex @value{GDBN} bugs, reporting | |
26527 | ||
26528 | A number of companies and individuals offer support for @sc{gnu} products. | |
26529 | If you obtained @value{GDBN} from a support organization, we recommend you | |
26530 | contact that organization first. | |
26531 | ||
26532 | You can find contact information for many support companies and | |
26533 | individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs | |
26534 | distribution. | |
26535 | @c should add a web page ref... | |
26536 | ||
c16158bc JM |
26537 | @ifset BUGURL |
26538 | @ifset BUGURL_DEFAULT | |
129188f6 | 26539 | In any event, we also recommend that you submit bug reports for |
d3e8051b | 26540 | @value{GDBN}. The preferred method is to submit them directly using |
129188f6 AC |
26541 | @uref{http://www.gnu.org/software/gdb/bugs/, @value{GDBN}'s Bugs web |
26542 | page}. Alternatively, the @email{bug-gdb@@gnu.org, e-mail gateway} can | |
26543 | be used. | |
8e04817f AC |
26544 | |
26545 | @strong{Do not send bug reports to @samp{info-gdb}, or to | |
26546 | @samp{help-gdb}, or to any newsgroups.} Most users of @value{GDBN} do | |
26547 | not want to receive bug reports. Those that do have arranged to receive | |
26548 | @samp{bug-gdb}. | |
26549 | ||
26550 | The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which | |
26551 | serves as a repeater. The mailing list and the newsgroup carry exactly | |
26552 | the same messages. Often people think of posting bug reports to the | |
26553 | newsgroup instead of mailing them. This appears to work, but it has one | |
26554 | problem which can be crucial: a newsgroup posting often lacks a mail | |
26555 | path back to the sender. Thus, if we need to ask for more information, | |
26556 | we may be unable to reach you. For this reason, it is better to send | |
26557 | bug reports to the mailing list. | |
c16158bc JM |
26558 | @end ifset |
26559 | @ifclear BUGURL_DEFAULT | |
26560 | In any event, we also recommend that you submit bug reports for | |
26561 | @value{GDBN} to @value{BUGURL}. | |
26562 | @end ifclear | |
26563 | @end ifset | |
c4555f82 | 26564 | |
8e04817f AC |
26565 | The fundamental principle of reporting bugs usefully is this: |
26566 | @strong{report all the facts}. If you are not sure whether to state a | |
26567 | fact or leave it out, state it! | |
c4555f82 | 26568 | |
8e04817f AC |
26569 | Often people omit facts because they think they know what causes the |
26570 | problem and assume that some details do not matter. Thus, you might | |
26571 | assume that the name of the variable you use in an example does not matter. | |
26572 | Well, probably it does not, but one cannot be sure. Perhaps the bug is a | |
26573 | stray memory reference which happens to fetch from the location where that | |
26574 | name is stored in memory; perhaps, if the name were different, the contents | |
26575 | of that location would fool the debugger into doing the right thing despite | |
26576 | the bug. Play it safe and give a specific, complete example. That is the | |
26577 | easiest thing for you to do, and the most helpful. | |
c4555f82 | 26578 | |
8e04817f AC |
26579 | Keep in mind that the purpose of a bug report is to enable us to fix the |
26580 | bug. It may be that the bug has been reported previously, but neither | |
26581 | you nor we can know that unless your bug report is complete and | |
26582 | self-contained. | |
c4555f82 | 26583 | |
8e04817f AC |
26584 | Sometimes people give a few sketchy facts and ask, ``Does this ring a |
26585 | bell?'' Those bug reports are useless, and we urge everyone to | |
26586 | @emph{refuse to respond to them} except to chide the sender to report | |
26587 | bugs properly. | |
26588 | ||
26589 | To enable us to fix the bug, you should include all these things: | |
c4555f82 SC |
26590 | |
26591 | @itemize @bullet | |
26592 | @item | |
8e04817f AC |
26593 | The version of @value{GDBN}. @value{GDBN} announces it if you start |
26594 | with no arguments; you can also print it at any time using @code{show | |
26595 | version}. | |
c4555f82 | 26596 | |
8e04817f AC |
26597 | Without this, we will not know whether there is any point in looking for |
26598 | the bug in the current version of @value{GDBN}. | |
c4555f82 SC |
26599 | |
26600 | @item | |
8e04817f AC |
26601 | The type of machine you are using, and the operating system name and |
26602 | version number. | |
c4555f82 SC |
26603 | |
26604 | @item | |
c1468174 | 26605 | What compiler (and its version) was used to compile @value{GDBN}---e.g.@: |
8e04817f | 26606 | ``@value{GCC}--2.8.1''. |
c4555f82 SC |
26607 | |
26608 | @item | |
8e04817f | 26609 | What compiler (and its version) was used to compile the program you are |
c1468174 | 26610 | debugging---e.g.@: ``@value{GCC}--2.8.1'', or ``HP92453-01 A.10.32.03 HP |
3f94c067 BW |
26611 | C Compiler''. For @value{NGCC}, you can say @kbd{@value{GCC} --version} |
26612 | to get this information; for other compilers, see the documentation for | |
26613 | those compilers. | |
c4555f82 | 26614 | |
8e04817f AC |
26615 | @item |
26616 | The command arguments you gave the compiler to compile your example and | |
26617 | observe the bug. For example, did you use @samp{-O}? To guarantee | |
26618 | you will not omit something important, list them all. A copy of the | |
26619 | Makefile (or the output from make) is sufficient. | |
c4555f82 | 26620 | |
8e04817f AC |
26621 | If we were to try to guess the arguments, we would probably guess wrong |
26622 | and then we might not encounter the bug. | |
c4555f82 | 26623 | |
8e04817f AC |
26624 | @item |
26625 | A complete input script, and all necessary source files, that will | |
26626 | reproduce the bug. | |
c4555f82 | 26627 | |
8e04817f AC |
26628 | @item |
26629 | A description of what behavior you observe that you believe is | |
26630 | incorrect. For example, ``It gets a fatal signal.'' | |
c4555f82 | 26631 | |
8e04817f AC |
26632 | Of course, if the bug is that @value{GDBN} gets a fatal signal, then we |
26633 | will certainly notice it. But if the bug is incorrect output, we might | |
26634 | not notice unless it is glaringly wrong. You might as well not give us | |
26635 | a chance to make a mistake. | |
c4555f82 | 26636 | |
8e04817f AC |
26637 | Even if the problem you experience is a fatal signal, you should still |
26638 | say so explicitly. Suppose something strange is going on, such as, your | |
26639 | copy of @value{GDBN} is out of synch, or you have encountered a bug in | |
26640 | the C library on your system. (This has happened!) Your copy might | |
26641 | crash and ours would not. If you told us to expect a crash, then when | |
26642 | ours fails to crash, we would know that the bug was not happening for | |
26643 | us. If you had not told us to expect a crash, then we would not be able | |
26644 | to draw any conclusion from our observations. | |
c4555f82 | 26645 | |
e0c07bf0 MC |
26646 | @pindex script |
26647 | @cindex recording a session script | |
26648 | To collect all this information, you can use a session recording program | |
26649 | such as @command{script}, which is available on many Unix systems. | |
26650 | Just run your @value{GDBN} session inside @command{script} and then | |
26651 | include the @file{typescript} file with your bug report. | |
26652 | ||
26653 | Another way to record a @value{GDBN} session is to run @value{GDBN} | |
26654 | inside Emacs and then save the entire buffer to a file. | |
26655 | ||
8e04817f AC |
26656 | @item |
26657 | If you wish to suggest changes to the @value{GDBN} source, send us context | |
26658 | diffs. If you even discuss something in the @value{GDBN} source, refer to | |
26659 | it by context, not by line number. | |
c4555f82 | 26660 | |
8e04817f AC |
26661 | The line numbers in our development sources will not match those in your |
26662 | sources. Your line numbers would convey no useful information to us. | |
c4555f82 | 26663 | |
8e04817f | 26664 | @end itemize |
c4555f82 | 26665 | |
8e04817f | 26666 | Here are some things that are not necessary: |
c4555f82 | 26667 | |
8e04817f AC |
26668 | @itemize @bullet |
26669 | @item | |
26670 | A description of the envelope of the bug. | |
c4555f82 | 26671 | |
8e04817f AC |
26672 | Often people who encounter a bug spend a lot of time investigating |
26673 | which changes to the input file will make the bug go away and which | |
26674 | changes will not affect it. | |
c4555f82 | 26675 | |
8e04817f AC |
26676 | This is often time consuming and not very useful, because the way we |
26677 | will find the bug is by running a single example under the debugger | |
26678 | with breakpoints, not by pure deduction from a series of examples. | |
26679 | We recommend that you save your time for something else. | |
c4555f82 | 26680 | |
8e04817f AC |
26681 | Of course, if you can find a simpler example to report @emph{instead} |
26682 | of the original one, that is a convenience for us. Errors in the | |
26683 | output will be easier to spot, running under the debugger will take | |
26684 | less time, and so on. | |
c4555f82 | 26685 | |
8e04817f AC |
26686 | However, simplification is not vital; if you do not want to do this, |
26687 | report the bug anyway and send us the entire test case you used. | |
c4555f82 | 26688 | |
8e04817f AC |
26689 | @item |
26690 | A patch for the bug. | |
c4555f82 | 26691 | |
8e04817f AC |
26692 | A patch for the bug does help us if it is a good one. But do not omit |
26693 | the necessary information, such as the test case, on the assumption that | |
26694 | a patch is all we need. We might see problems with your patch and decide | |
26695 | to fix the problem another way, or we might not understand it at all. | |
c4555f82 | 26696 | |
8e04817f AC |
26697 | Sometimes with a program as complicated as @value{GDBN} it is very hard to |
26698 | construct an example that will make the program follow a certain path | |
26699 | through the code. If you do not send us the example, we will not be able | |
26700 | to construct one, so we will not be able to verify that the bug is fixed. | |
c4555f82 | 26701 | |
8e04817f AC |
26702 | And if we cannot understand what bug you are trying to fix, or why your |
26703 | patch should be an improvement, we will not install it. A test case will | |
26704 | help us to understand. | |
c4555f82 | 26705 | |
8e04817f AC |
26706 | @item |
26707 | A guess about what the bug is or what it depends on. | |
c4555f82 | 26708 | |
8e04817f AC |
26709 | Such guesses are usually wrong. Even we cannot guess right about such |
26710 | things without first using the debugger to find the facts. | |
26711 | @end itemize | |
c4555f82 | 26712 | |
8e04817f AC |
26713 | @c The readline documentation is distributed with the readline code |
26714 | @c and consists of the two following files: | |
26715 | @c rluser.texinfo | |
26716 | @c inc-hist.texinfo | |
26717 | @c Use -I with makeinfo to point to the appropriate directory, | |
26718 | @c environment var TEXINPUTS with TeX. | |
5bdf8622 | 26719 | @include rluser.texi |
8e04817f | 26720 | @include inc-hist.texinfo |
c4555f82 | 26721 | |
c4555f82 | 26722 | |
8e04817f AC |
26723 | @node Formatting Documentation |
26724 | @appendix Formatting Documentation | |
c4555f82 | 26725 | |
8e04817f AC |
26726 | @cindex @value{GDBN} reference card |
26727 | @cindex reference card | |
26728 | The @value{GDBN} 4 release includes an already-formatted reference card, ready | |
26729 | for printing with PostScript or Ghostscript, in the @file{gdb} | |
26730 | subdirectory of the main source directory@footnote{In | |
26731 | @file{gdb-@value{GDBVN}/gdb/refcard.ps} of the version @value{GDBVN} | |
26732 | release.}. If you can use PostScript or Ghostscript with your printer, | |
26733 | you can print the reference card immediately with @file{refcard.ps}. | |
c4555f82 | 26734 | |
8e04817f AC |
26735 | The release also includes the source for the reference card. You |
26736 | can format it, using @TeX{}, by typing: | |
c4555f82 | 26737 | |
474c8240 | 26738 | @smallexample |
8e04817f | 26739 | make refcard.dvi |
474c8240 | 26740 | @end smallexample |
c4555f82 | 26741 | |
8e04817f AC |
26742 | The @value{GDBN} reference card is designed to print in @dfn{landscape} |
26743 | mode on US ``letter'' size paper; | |
26744 | that is, on a sheet 11 inches wide by 8.5 inches | |
26745 | high. You will need to specify this form of printing as an option to | |
26746 | your @sc{dvi} output program. | |
c4555f82 | 26747 | |
8e04817f | 26748 | @cindex documentation |
c4555f82 | 26749 | |
8e04817f AC |
26750 | All the documentation for @value{GDBN} comes as part of the machine-readable |
26751 | distribution. The documentation is written in Texinfo format, which is | |
26752 | a documentation system that uses a single source file to produce both | |
26753 | on-line information and a printed manual. You can use one of the Info | |
26754 | formatting commands to create the on-line version of the documentation | |
26755 | and @TeX{} (or @code{texi2roff}) to typeset the printed version. | |
c4555f82 | 26756 | |
8e04817f AC |
26757 | @value{GDBN} includes an already formatted copy of the on-line Info |
26758 | version of this manual in the @file{gdb} subdirectory. The main Info | |
26759 | file is @file{gdb-@value{GDBVN}/gdb/gdb.info}, and it refers to | |
26760 | subordinate files matching @samp{gdb.info*} in the same directory. If | |
26761 | necessary, you can print out these files, or read them with any editor; | |
26762 | but they are easier to read using the @code{info} subsystem in @sc{gnu} | |
26763 | Emacs or the standalone @code{info} program, available as part of the | |
26764 | @sc{gnu} Texinfo distribution. | |
c4555f82 | 26765 | |
8e04817f AC |
26766 | If you want to format these Info files yourself, you need one of the |
26767 | Info formatting programs, such as @code{texinfo-format-buffer} or | |
26768 | @code{makeinfo}. | |
c4555f82 | 26769 | |
8e04817f AC |
26770 | If you have @code{makeinfo} installed, and are in the top level |
26771 | @value{GDBN} source directory (@file{gdb-@value{GDBVN}}, in the case of | |
26772 | version @value{GDBVN}), you can make the Info file by typing: | |
c4555f82 | 26773 | |
474c8240 | 26774 | @smallexample |
8e04817f AC |
26775 | cd gdb |
26776 | make gdb.info | |
474c8240 | 26777 | @end smallexample |
c4555f82 | 26778 | |
8e04817f AC |
26779 | If you want to typeset and print copies of this manual, you need @TeX{}, |
26780 | a program to print its @sc{dvi} output files, and @file{texinfo.tex}, the | |
26781 | Texinfo definitions file. | |
c4555f82 | 26782 | |
8e04817f AC |
26783 | @TeX{} is a typesetting program; it does not print files directly, but |
26784 | produces output files called @sc{dvi} files. To print a typeset | |
26785 | document, you need a program to print @sc{dvi} files. If your system | |
26786 | has @TeX{} installed, chances are it has such a program. The precise | |
26787 | command to use depends on your system; @kbd{lpr -d} is common; another | |
26788 | (for PostScript devices) is @kbd{dvips}. The @sc{dvi} print command may | |
26789 | require a file name without any extension or a @samp{.dvi} extension. | |
c4555f82 | 26790 | |
8e04817f AC |
26791 | @TeX{} also requires a macro definitions file called |
26792 | @file{texinfo.tex}. This file tells @TeX{} how to typeset a document | |
26793 | written in Texinfo format. On its own, @TeX{} cannot either read or | |
26794 | typeset a Texinfo file. @file{texinfo.tex} is distributed with GDB | |
26795 | and is located in the @file{gdb-@var{version-number}/texinfo} | |
26796 | directory. | |
c4555f82 | 26797 | |
8e04817f | 26798 | If you have @TeX{} and a @sc{dvi} printer program installed, you can |
d3e8051b | 26799 | typeset and print this manual. First switch to the @file{gdb} |
8e04817f AC |
26800 | subdirectory of the main source directory (for example, to |
26801 | @file{gdb-@value{GDBVN}/gdb}) and type: | |
c4555f82 | 26802 | |
474c8240 | 26803 | @smallexample |
8e04817f | 26804 | make gdb.dvi |
474c8240 | 26805 | @end smallexample |
c4555f82 | 26806 | |
8e04817f | 26807 | Then give @file{gdb.dvi} to your @sc{dvi} printing program. |
c4555f82 | 26808 | |
8e04817f AC |
26809 | @node Installing GDB |
26810 | @appendix Installing @value{GDBN} | |
8e04817f | 26811 | @cindex installation |
c4555f82 | 26812 | |
7fa2210b DJ |
26813 | @menu |
26814 | * Requirements:: Requirements for building @value{GDBN} | |
db2e3e2e | 26815 | * Running Configure:: Invoking the @value{GDBN} @file{configure} script |
7fa2210b DJ |
26816 | * Separate Objdir:: Compiling @value{GDBN} in another directory |
26817 | * Config Names:: Specifying names for hosts and targets | |
26818 | * Configure Options:: Summary of options for configure | |
098b41a6 | 26819 | * System-wide configuration:: Having a system-wide init file |
7fa2210b DJ |
26820 | @end menu |
26821 | ||
26822 | @node Requirements | |
79a6e687 | 26823 | @section Requirements for Building @value{GDBN} |
7fa2210b DJ |
26824 | @cindex building @value{GDBN}, requirements for |
26825 | ||
26826 | Building @value{GDBN} requires various tools and packages to be available. | |
26827 | Other packages will be used only if they are found. | |
26828 | ||
79a6e687 | 26829 | @heading Tools/Packages Necessary for Building @value{GDBN} |
7fa2210b DJ |
26830 | @table @asis |
26831 | @item ISO C90 compiler | |
26832 | @value{GDBN} is written in ISO C90. It should be buildable with any | |
26833 | working C90 compiler, e.g.@: GCC. | |
26834 | ||
26835 | @end table | |
26836 | ||
79a6e687 | 26837 | @heading Tools/Packages Optional for Building @value{GDBN} |
7fa2210b DJ |
26838 | @table @asis |
26839 | @item Expat | |
123dc839 | 26840 | @anchor{Expat} |
7fa2210b DJ |
26841 | @value{GDBN} can use the Expat XML parsing library. This library may be |
26842 | included with your operating system distribution; if it is not, you | |
26843 | can get the latest version from @url{http://expat.sourceforge.net}. | |
db2e3e2e | 26844 | The @file{configure} script will search for this library in several |
7fa2210b DJ |
26845 | standard locations; if it is installed in an unusual path, you can |
26846 | use the @option{--with-libexpat-prefix} option to specify its location. | |
26847 | ||
9cceb671 DJ |
26848 | Expat is used for: |
26849 | ||
26850 | @itemize @bullet | |
26851 | @item | |
26852 | Remote protocol memory maps (@pxref{Memory Map Format}) | |
26853 | @item | |
26854 | Target descriptions (@pxref{Target Descriptions}) | |
26855 | @item | |
26856 | Remote shared library lists (@pxref{Library List Format}) | |
26857 | @item | |
26858 | MS-Windows shared libraries (@pxref{Shared Libraries}) | |
26859 | @end itemize | |
7fa2210b | 26860 | |
31fffb02 CS |
26861 | @item zlib |
26862 | @cindex compressed debug sections | |
26863 | @value{GDBN} will use the @samp{zlib} library, if available, to read | |
26864 | compressed debug sections. Some linkers, such as GNU gold, are capable | |
26865 | of producing binaries with compressed debug sections. If @value{GDBN} | |
26866 | is compiled with @samp{zlib}, it will be able to read the debug | |
26867 | information in such binaries. | |
26868 | ||
26869 | The @samp{zlib} library is likely included with your operating system | |
26870 | distribution; if it is not, you can get the latest version from | |
26871 | @url{http://zlib.net}. | |
26872 | ||
6c7a06a3 TT |
26873 | @item iconv |
26874 | @value{GDBN}'s features related to character sets (@pxref{Character | |
26875 | Sets}) require a functioning @code{iconv} implementation. If you are | |
26876 | on a GNU system, then this is provided by the GNU C Library. Some | |
26877 | other systems also provide a working @code{iconv}. | |
26878 | ||
26879 | On systems with @code{iconv}, you can install GNU Libiconv. If you | |
26880 | have previously installed Libiconv, you can use the | |
26881 | @option{--with-libiconv-prefix} option to configure. | |
26882 | ||
26883 | @value{GDBN}'s top-level @file{configure} and @file{Makefile} will | |
26884 | arrange to build Libiconv if a directory named @file{libiconv} appears | |
26885 | in the top-most source directory. If Libiconv is built this way, and | |
26886 | if the operating system does not provide a suitable @code{iconv} | |
26887 | implementation, then the just-built library will automatically be used | |
26888 | by @value{GDBN}. One easy way to set this up is to download GNU | |
26889 | Libiconv, unpack it, and then rename the directory holding the | |
26890 | Libiconv source code to @samp{libiconv}. | |
7fa2210b DJ |
26891 | @end table |
26892 | ||
26893 | @node Running Configure | |
db2e3e2e | 26894 | @section Invoking the @value{GDBN} @file{configure} Script |
7fa2210b | 26895 | @cindex configuring @value{GDBN} |
db2e3e2e | 26896 | @value{GDBN} comes with a @file{configure} script that automates the process |
8e04817f AC |
26897 | of preparing @value{GDBN} for installation; you can then use @code{make} to |
26898 | build the @code{gdb} program. | |
26899 | @iftex | |
26900 | @c irrelevant in info file; it's as current as the code it lives with. | |
26901 | @footnote{If you have a more recent version of @value{GDBN} than @value{GDBVN}, | |
26902 | look at the @file{README} file in the sources; we may have improved the | |
26903 | installation procedures since publishing this manual.} | |
26904 | @end iftex | |
c4555f82 | 26905 | |
8e04817f AC |
26906 | The @value{GDBN} distribution includes all the source code you need for |
26907 | @value{GDBN} in a single directory, whose name is usually composed by | |
26908 | appending the version number to @samp{gdb}. | |
c4555f82 | 26909 | |
8e04817f AC |
26910 | For example, the @value{GDBN} version @value{GDBVN} distribution is in the |
26911 | @file{gdb-@value{GDBVN}} directory. That directory contains: | |
c4555f82 | 26912 | |
8e04817f AC |
26913 | @table @code |
26914 | @item gdb-@value{GDBVN}/configure @r{(and supporting files)} | |
26915 | script for configuring @value{GDBN} and all its supporting libraries | |
c4555f82 | 26916 | |
8e04817f AC |
26917 | @item gdb-@value{GDBVN}/gdb |
26918 | the source specific to @value{GDBN} itself | |
c4555f82 | 26919 | |
8e04817f AC |
26920 | @item gdb-@value{GDBVN}/bfd |
26921 | source for the Binary File Descriptor library | |
c906108c | 26922 | |
8e04817f AC |
26923 | @item gdb-@value{GDBVN}/include |
26924 | @sc{gnu} include files | |
c906108c | 26925 | |
8e04817f AC |
26926 | @item gdb-@value{GDBVN}/libiberty |
26927 | source for the @samp{-liberty} free software library | |
c906108c | 26928 | |
8e04817f AC |
26929 | @item gdb-@value{GDBVN}/opcodes |
26930 | source for the library of opcode tables and disassemblers | |
c906108c | 26931 | |
8e04817f AC |
26932 | @item gdb-@value{GDBVN}/readline |
26933 | source for the @sc{gnu} command-line interface | |
c906108c | 26934 | |
8e04817f AC |
26935 | @item gdb-@value{GDBVN}/glob |
26936 | source for the @sc{gnu} filename pattern-matching subroutine | |
c906108c | 26937 | |
8e04817f AC |
26938 | @item gdb-@value{GDBVN}/mmalloc |
26939 | source for the @sc{gnu} memory-mapped malloc package | |
26940 | @end table | |
c906108c | 26941 | |
db2e3e2e | 26942 | The simplest way to configure and build @value{GDBN} is to run @file{configure} |
8e04817f AC |
26943 | from the @file{gdb-@var{version-number}} source directory, which in |
26944 | this example is the @file{gdb-@value{GDBVN}} directory. | |
c906108c | 26945 | |
8e04817f | 26946 | First switch to the @file{gdb-@var{version-number}} source directory |
db2e3e2e | 26947 | if you are not already in it; then run @file{configure}. Pass the |
8e04817f AC |
26948 | identifier for the platform on which @value{GDBN} will run as an |
26949 | argument. | |
c906108c | 26950 | |
8e04817f | 26951 | For example: |
c906108c | 26952 | |
474c8240 | 26953 | @smallexample |
8e04817f AC |
26954 | cd gdb-@value{GDBVN} |
26955 | ./configure @var{host} | |
26956 | make | |
474c8240 | 26957 | @end smallexample |
c906108c | 26958 | |
8e04817f AC |
26959 | @noindent |
26960 | where @var{host} is an identifier such as @samp{sun4} or | |
26961 | @samp{decstation}, that identifies the platform where @value{GDBN} will run. | |
db2e3e2e | 26962 | (You can often leave off @var{host}; @file{configure} tries to guess the |
8e04817f | 26963 | correct value by examining your system.) |
c906108c | 26964 | |
8e04817f AC |
26965 | Running @samp{configure @var{host}} and then running @code{make} builds the |
26966 | @file{bfd}, @file{readline}, @file{mmalloc}, and @file{libiberty} | |
26967 | libraries, then @code{gdb} itself. The configured source files, and the | |
26968 | binaries, are left in the corresponding source directories. | |
c906108c | 26969 | |
8e04817f | 26970 | @need 750 |
db2e3e2e | 26971 | @file{configure} is a Bourne-shell (@code{/bin/sh}) script; if your |
8e04817f AC |
26972 | system does not recognize this automatically when you run a different |
26973 | shell, you may need to run @code{sh} on it explicitly: | |
c906108c | 26974 | |
474c8240 | 26975 | @smallexample |
8e04817f | 26976 | sh configure @var{host} |
474c8240 | 26977 | @end smallexample |
c906108c | 26978 | |
db2e3e2e | 26979 | If you run @file{configure} from a directory that contains source |
8e04817f | 26980 | directories for multiple libraries or programs, such as the |
db2e3e2e BW |
26981 | @file{gdb-@value{GDBVN}} source directory for version @value{GDBVN}, |
26982 | @file{configure} | |
8e04817f AC |
26983 | creates configuration files for every directory level underneath (unless |
26984 | you tell it not to, with the @samp{--norecursion} option). | |
26985 | ||
db2e3e2e | 26986 | You should run the @file{configure} script from the top directory in the |
94e91d6d | 26987 | source tree, the @file{gdb-@var{version-number}} directory. If you run |
db2e3e2e | 26988 | @file{configure} from one of the subdirectories, you will configure only |
94e91d6d | 26989 | that subdirectory. That is usually not what you want. In particular, |
db2e3e2e | 26990 | if you run the first @file{configure} from the @file{gdb} subdirectory |
94e91d6d MC |
26991 | of the @file{gdb-@var{version-number}} directory, you will omit the |
26992 | configuration of @file{bfd}, @file{readline}, and other sibling | |
26993 | directories of the @file{gdb} subdirectory. This leads to build errors | |
26994 | about missing include files such as @file{bfd/bfd.h}. | |
c906108c | 26995 | |
8e04817f AC |
26996 | You can install @code{@value{GDBP}} anywhere; it has no hardwired paths. |
26997 | However, you should make sure that the shell on your path (named by | |
26998 | the @samp{SHELL} environment variable) is publicly readable. Remember | |
26999 | that @value{GDBN} uses the shell to start your program---some systems refuse to | |
27000 | let @value{GDBN} debug child processes whose programs are not readable. | |
c906108c | 27001 | |
8e04817f | 27002 | @node Separate Objdir |
79a6e687 | 27003 | @section Compiling @value{GDBN} in Another Directory |
c906108c | 27004 | |
8e04817f AC |
27005 | If you want to run @value{GDBN} versions for several host or target machines, |
27006 | you need a different @code{gdb} compiled for each combination of | |
db2e3e2e | 27007 | host and target. @file{configure} is designed to make this easy by |
8e04817f AC |
27008 | allowing you to generate each configuration in a separate subdirectory, |
27009 | rather than in the source directory. If your @code{make} program | |
27010 | handles the @samp{VPATH} feature (@sc{gnu} @code{make} does), running | |
27011 | @code{make} in each of these directories builds the @code{gdb} | |
27012 | program specified there. | |
c906108c | 27013 | |
db2e3e2e | 27014 | To build @code{gdb} in a separate directory, run @file{configure} |
8e04817f | 27015 | with the @samp{--srcdir} option to specify where to find the source. |
db2e3e2e BW |
27016 | (You also need to specify a path to find @file{configure} |
27017 | itself from your working directory. If the path to @file{configure} | |
8e04817f AC |
27018 | would be the same as the argument to @samp{--srcdir}, you can leave out |
27019 | the @samp{--srcdir} option; it is assumed.) | |
c906108c | 27020 | |
8e04817f AC |
27021 | For example, with version @value{GDBVN}, you can build @value{GDBN} in a |
27022 | separate directory for a Sun 4 like this: | |
c906108c | 27023 | |
474c8240 | 27024 | @smallexample |
8e04817f AC |
27025 | @group |
27026 | cd gdb-@value{GDBVN} | |
27027 | mkdir ../gdb-sun4 | |
27028 | cd ../gdb-sun4 | |
27029 | ../gdb-@value{GDBVN}/configure sun4 | |
27030 | make | |
27031 | @end group | |
474c8240 | 27032 | @end smallexample |
c906108c | 27033 | |
db2e3e2e | 27034 | When @file{configure} builds a configuration using a remote source |
8e04817f AC |
27035 | directory, it creates a tree for the binaries with the same structure |
27036 | (and using the same names) as the tree under the source directory. In | |
27037 | the example, you'd find the Sun 4 library @file{libiberty.a} in the | |
27038 | directory @file{gdb-sun4/libiberty}, and @value{GDBN} itself in | |
27039 | @file{gdb-sun4/gdb}. | |
c906108c | 27040 | |
94e91d6d MC |
27041 | Make sure that your path to the @file{configure} script has just one |
27042 | instance of @file{gdb} in it. If your path to @file{configure} looks | |
27043 | like @file{../gdb-@value{GDBVN}/gdb/configure}, you are configuring only | |
27044 | one subdirectory of @value{GDBN}, not the whole package. This leads to | |
27045 | build errors about missing include files such as @file{bfd/bfd.h}. | |
27046 | ||
8e04817f AC |
27047 | One popular reason to build several @value{GDBN} configurations in separate |
27048 | directories is to configure @value{GDBN} for cross-compiling (where | |
27049 | @value{GDBN} runs on one machine---the @dfn{host}---while debugging | |
27050 | programs that run on another machine---the @dfn{target}). | |
27051 | You specify a cross-debugging target by | |
db2e3e2e | 27052 | giving the @samp{--target=@var{target}} option to @file{configure}. |
c906108c | 27053 | |
8e04817f AC |
27054 | When you run @code{make} to build a program or library, you must run |
27055 | it in a configured directory---whatever directory you were in when you | |
db2e3e2e | 27056 | called @file{configure} (or one of its subdirectories). |
c906108c | 27057 | |
db2e3e2e | 27058 | The @code{Makefile} that @file{configure} generates in each source |
8e04817f AC |
27059 | directory also runs recursively. If you type @code{make} in a source |
27060 | directory such as @file{gdb-@value{GDBVN}} (or in a separate configured | |
27061 | directory configured with @samp{--srcdir=@var{dirname}/gdb-@value{GDBVN}}), you | |
27062 | will build all the required libraries, and then build GDB. | |
c906108c | 27063 | |
8e04817f AC |
27064 | When you have multiple hosts or targets configured in separate |
27065 | directories, you can run @code{make} on them in parallel (for example, | |
27066 | if they are NFS-mounted on each of the hosts); they will not interfere | |
27067 | with each other. | |
c906108c | 27068 | |
8e04817f | 27069 | @node Config Names |
79a6e687 | 27070 | @section Specifying Names for Hosts and Targets |
c906108c | 27071 | |
db2e3e2e | 27072 | The specifications used for hosts and targets in the @file{configure} |
8e04817f AC |
27073 | script are based on a three-part naming scheme, but some short predefined |
27074 | aliases are also supported. The full naming scheme encodes three pieces | |
27075 | of information in the following pattern: | |
c906108c | 27076 | |
474c8240 | 27077 | @smallexample |
8e04817f | 27078 | @var{architecture}-@var{vendor}-@var{os} |
474c8240 | 27079 | @end smallexample |
c906108c | 27080 | |
8e04817f AC |
27081 | For example, you can use the alias @code{sun4} as a @var{host} argument, |
27082 | or as the value for @var{target} in a @code{--target=@var{target}} | |
27083 | option. The equivalent full name is @samp{sparc-sun-sunos4}. | |
c906108c | 27084 | |
db2e3e2e | 27085 | The @file{configure} script accompanying @value{GDBN} does not provide |
8e04817f | 27086 | any query facility to list all supported host and target names or |
db2e3e2e | 27087 | aliases. @file{configure} calls the Bourne shell script |
8e04817f AC |
27088 | @code{config.sub} to map abbreviations to full names; you can read the |
27089 | script, if you wish, or you can use it to test your guesses on | |
27090 | abbreviations---for example: | |
c906108c | 27091 | |
8e04817f AC |
27092 | @smallexample |
27093 | % sh config.sub i386-linux | |
27094 | i386-pc-linux-gnu | |
27095 | % sh config.sub alpha-linux | |
27096 | alpha-unknown-linux-gnu | |
27097 | % sh config.sub hp9k700 | |
27098 | hppa1.1-hp-hpux | |
27099 | % sh config.sub sun4 | |
27100 | sparc-sun-sunos4.1.1 | |
27101 | % sh config.sub sun3 | |
27102 | m68k-sun-sunos4.1.1 | |
27103 | % sh config.sub i986v | |
27104 | Invalid configuration `i986v': machine `i986v' not recognized | |
27105 | @end smallexample | |
c906108c | 27106 | |
8e04817f AC |
27107 | @noindent |
27108 | @code{config.sub} is also distributed in the @value{GDBN} source | |
27109 | directory (@file{gdb-@value{GDBVN}}, for version @value{GDBVN}). | |
d700128c | 27110 | |
8e04817f | 27111 | @node Configure Options |
db2e3e2e | 27112 | @section @file{configure} Options |
c906108c | 27113 | |
db2e3e2e BW |
27114 | Here is a summary of the @file{configure} options and arguments that |
27115 | are most often useful for building @value{GDBN}. @file{configure} also has | |
8e04817f | 27116 | several other options not listed here. @inforef{What Configure |
db2e3e2e | 27117 | Does,,configure.info}, for a full explanation of @file{configure}. |
c906108c | 27118 | |
474c8240 | 27119 | @smallexample |
8e04817f AC |
27120 | configure @r{[}--help@r{]} |
27121 | @r{[}--prefix=@var{dir}@r{]} | |
27122 | @r{[}--exec-prefix=@var{dir}@r{]} | |
27123 | @r{[}--srcdir=@var{dirname}@r{]} | |
27124 | @r{[}--norecursion@r{]} @r{[}--rm@r{]} | |
27125 | @r{[}--target=@var{target}@r{]} | |
27126 | @var{host} | |
474c8240 | 27127 | @end smallexample |
c906108c | 27128 | |
8e04817f AC |
27129 | @noindent |
27130 | You may introduce options with a single @samp{-} rather than | |
27131 | @samp{--} if you prefer; but you may abbreviate option names if you use | |
27132 | @samp{--}. | |
c906108c | 27133 | |
8e04817f AC |
27134 | @table @code |
27135 | @item --help | |
db2e3e2e | 27136 | Display a quick summary of how to invoke @file{configure}. |
c906108c | 27137 | |
8e04817f AC |
27138 | @item --prefix=@var{dir} |
27139 | Configure the source to install programs and files under directory | |
27140 | @file{@var{dir}}. | |
c906108c | 27141 | |
8e04817f AC |
27142 | @item --exec-prefix=@var{dir} |
27143 | Configure the source to install programs under directory | |
27144 | @file{@var{dir}}. | |
c906108c | 27145 | |
8e04817f AC |
27146 | @c avoid splitting the warning from the explanation: |
27147 | @need 2000 | |
27148 | @item --srcdir=@var{dirname} | |
27149 | @strong{Warning: using this option requires @sc{gnu} @code{make}, or another | |
27150 | @code{make} that implements the @code{VPATH} feature.}@* | |
27151 | Use this option to make configurations in directories separate from the | |
27152 | @value{GDBN} source directories. Among other things, you can use this to | |
27153 | build (or maintain) several configurations simultaneously, in separate | |
db2e3e2e | 27154 | directories. @file{configure} writes configuration-specific files in |
8e04817f | 27155 | the current directory, but arranges for them to use the source in the |
db2e3e2e | 27156 | directory @var{dirname}. @file{configure} creates directories under |
8e04817f AC |
27157 | the working directory in parallel to the source directories below |
27158 | @var{dirname}. | |
c906108c | 27159 | |
8e04817f | 27160 | @item --norecursion |
db2e3e2e | 27161 | Configure only the directory level where @file{configure} is executed; do not |
8e04817f | 27162 | propagate configuration to subdirectories. |
c906108c | 27163 | |
8e04817f AC |
27164 | @item --target=@var{target} |
27165 | Configure @value{GDBN} for cross-debugging programs running on the specified | |
27166 | @var{target}. Without this option, @value{GDBN} is configured to debug | |
27167 | programs that run on the same machine (@var{host}) as @value{GDBN} itself. | |
c906108c | 27168 | |
8e04817f | 27169 | There is no convenient way to generate a list of all available targets. |
c906108c | 27170 | |
8e04817f AC |
27171 | @item @var{host} @dots{} |
27172 | Configure @value{GDBN} to run on the specified @var{host}. | |
c906108c | 27173 | |
8e04817f AC |
27174 | There is no convenient way to generate a list of all available hosts. |
27175 | @end table | |
c906108c | 27176 | |
8e04817f AC |
27177 | There are many other options available as well, but they are generally |
27178 | needed for special purposes only. | |
c906108c | 27179 | |
098b41a6 JG |
27180 | @node System-wide configuration |
27181 | @section System-wide configuration and settings | |
27182 | @cindex system-wide init file | |
27183 | ||
27184 | @value{GDBN} can be configured to have a system-wide init file; | |
27185 | this file will be read and executed at startup (@pxref{Startup, , What | |
27186 | @value{GDBN} does during startup}). | |
27187 | ||
27188 | Here is the corresponding configure option: | |
27189 | ||
27190 | @table @code | |
27191 | @item --with-system-gdbinit=@var{file} | |
27192 | Specify that the default location of the system-wide init file is | |
27193 | @var{file}. | |
27194 | @end table | |
27195 | ||
27196 | If @value{GDBN} has been configured with the option @option{--prefix=$prefix}, | |
27197 | it may be subject to relocation. Two possible cases: | |
27198 | ||
27199 | @itemize @bullet | |
27200 | @item | |
27201 | If the default location of this init file contains @file{$prefix}, | |
27202 | it will be subject to relocation. Suppose that the configure options | |
27203 | are @option{--prefix=$prefix --with-system-gdbinit=$prefix/etc/gdbinit}; | |
27204 | if @value{GDBN} is moved from @file{$prefix} to @file{$install}, the system | |
27205 | init file is looked for as @file{$install/etc/gdbinit} instead of | |
27206 | @file{$prefix/etc/gdbinit}. | |
27207 | ||
27208 | @item | |
27209 | By contrast, if the default location does not contain the prefix, | |
27210 | it will not be relocated. E.g.@: if @value{GDBN} has been configured with | |
27211 | @option{--prefix=/usr/local --with-system-gdbinit=/usr/share/gdb/gdbinit}, | |
27212 | then @value{GDBN} will always look for @file{/usr/share/gdb/gdbinit}, | |
27213 | wherever @value{GDBN} is installed. | |
27214 | @end itemize | |
27215 | ||
8e04817f AC |
27216 | @node Maintenance Commands |
27217 | @appendix Maintenance Commands | |
27218 | @cindex maintenance commands | |
27219 | @cindex internal commands | |
c906108c | 27220 | |
8e04817f | 27221 | In addition to commands intended for @value{GDBN} users, @value{GDBN} |
09d4efe1 EZ |
27222 | includes a number of commands intended for @value{GDBN} developers, |
27223 | that are not documented elsewhere in this manual. These commands are | |
da316a69 EZ |
27224 | provided here for reference. (For commands that turn on debugging |
27225 | messages, see @ref{Debugging Output}.) | |
c906108c | 27226 | |
8e04817f | 27227 | @table @code |
09d4efe1 | 27228 | @kindex maint agent |
782b2b07 | 27229 | @kindex maint agent-eval |
09d4efe1 | 27230 | @item maint agent @var{expression} |
782b2b07 | 27231 | @itemx maint agent-eval @var{expression} |
09d4efe1 EZ |
27232 | Translate the given @var{expression} into remote agent bytecodes. |
27233 | This command is useful for debugging the Agent Expression mechanism | |
782b2b07 SS |
27234 | (@pxref{Agent Expressions}). The @samp{agent} version produces an |
27235 | expression useful for data collection, such as by tracepoints, while | |
27236 | @samp{maint agent-eval} produces an expression that evaluates directly | |
27237 | to a result. For instance, a collection expression for @code{globa + | |
27238 | globb} will include bytecodes to record four bytes of memory at each | |
27239 | of the addresses of @code{globa} and @code{globb}, while discarding | |
27240 | the result of the addition, while an evaluation expression will do the | |
27241 | addition and return the sum. | |
09d4efe1 | 27242 | |
8e04817f AC |
27243 | @kindex maint info breakpoints |
27244 | @item @anchor{maint info breakpoints}maint info breakpoints | |
27245 | Using the same format as @samp{info breakpoints}, display both the | |
27246 | breakpoints you've set explicitly, and those @value{GDBN} is using for | |
27247 | internal purposes. Internal breakpoints are shown with negative | |
27248 | breakpoint numbers. The type column identifies what kind of breakpoint | |
27249 | is shown: | |
c906108c | 27250 | |
8e04817f AC |
27251 | @table @code |
27252 | @item breakpoint | |
27253 | Normal, explicitly set breakpoint. | |
c906108c | 27254 | |
8e04817f AC |
27255 | @item watchpoint |
27256 | Normal, explicitly set watchpoint. | |
c906108c | 27257 | |
8e04817f AC |
27258 | @item longjmp |
27259 | Internal breakpoint, used to handle correctly stepping through | |
27260 | @code{longjmp} calls. | |
c906108c | 27261 | |
8e04817f AC |
27262 | @item longjmp resume |
27263 | Internal breakpoint at the target of a @code{longjmp}. | |
c906108c | 27264 | |
8e04817f AC |
27265 | @item until |
27266 | Temporary internal breakpoint used by the @value{GDBN} @code{until} command. | |
c906108c | 27267 | |
8e04817f AC |
27268 | @item finish |
27269 | Temporary internal breakpoint used by the @value{GDBN} @code{finish} command. | |
c906108c | 27270 | |
8e04817f AC |
27271 | @item shlib events |
27272 | Shared library events. | |
c906108c | 27273 | |
8e04817f | 27274 | @end table |
c906108c | 27275 | |
fff08868 HZ |
27276 | @kindex set displaced-stepping |
27277 | @kindex show displaced-stepping | |
237fc4c9 PA |
27278 | @cindex displaced stepping support |
27279 | @cindex out-of-line single-stepping | |
fff08868 HZ |
27280 | @item set displaced-stepping |
27281 | @itemx show displaced-stepping | |
237fc4c9 | 27282 | Control whether or not @value{GDBN} will do @dfn{displaced stepping} |
fff08868 HZ |
27283 | if the target supports it. Displaced stepping is a way to single-step |
27284 | over breakpoints without removing them from the inferior, by executing | |
27285 | an out-of-line copy of the instruction that was originally at the | |
27286 | breakpoint location. It is also known as out-of-line single-stepping. | |
27287 | ||
27288 | @table @code | |
27289 | @item set displaced-stepping on | |
27290 | If the target architecture supports it, @value{GDBN} will use | |
27291 | displaced stepping to step over breakpoints. | |
27292 | ||
27293 | @item set displaced-stepping off | |
27294 | @value{GDBN} will not use displaced stepping to step over breakpoints, | |
27295 | even if such is supported by the target architecture. | |
27296 | ||
27297 | @cindex non-stop mode, and @samp{set displaced-stepping} | |
27298 | @item set displaced-stepping auto | |
27299 | This is the default mode. @value{GDBN} will use displaced stepping | |
27300 | only if non-stop mode is active (@pxref{Non-Stop Mode}) and the target | |
27301 | architecture supports displaced stepping. | |
27302 | @end table | |
237fc4c9 | 27303 | |
09d4efe1 EZ |
27304 | @kindex maint check-symtabs |
27305 | @item maint check-symtabs | |
27306 | Check the consistency of psymtabs and symtabs. | |
27307 | ||
27308 | @kindex maint cplus first_component | |
27309 | @item maint cplus first_component @var{name} | |
27310 | Print the first C@t{++} class/namespace component of @var{name}. | |
27311 | ||
27312 | @kindex maint cplus namespace | |
27313 | @item maint cplus namespace | |
27314 | Print the list of possible C@t{++} namespaces. | |
27315 | ||
27316 | @kindex maint demangle | |
27317 | @item maint demangle @var{name} | |
d3e8051b | 27318 | Demangle a C@t{++} or Objective-C mangled @var{name}. |
09d4efe1 EZ |
27319 | |
27320 | @kindex maint deprecate | |
27321 | @kindex maint undeprecate | |
27322 | @cindex deprecated commands | |
27323 | @item maint deprecate @var{command} @r{[}@var{replacement}@r{]} | |
27324 | @itemx maint undeprecate @var{command} | |
27325 | Deprecate or undeprecate the named @var{command}. Deprecated commands | |
27326 | cause @value{GDBN} to issue a warning when you use them. The optional | |
27327 | argument @var{replacement} says which newer command should be used in | |
27328 | favor of the deprecated one; if it is given, @value{GDBN} will mention | |
27329 | the replacement as part of the warning. | |
27330 | ||
27331 | @kindex maint dump-me | |
27332 | @item maint dump-me | |
721c2651 | 27333 | @cindex @code{SIGQUIT} signal, dump core of @value{GDBN} |
09d4efe1 | 27334 | Cause a fatal signal in the debugger and force it to dump its core. |
721c2651 EZ |
27335 | This is supported only on systems which support aborting a program |
27336 | with the @code{SIGQUIT} signal. | |
09d4efe1 | 27337 | |
8d30a00d AC |
27338 | @kindex maint internal-error |
27339 | @kindex maint internal-warning | |
09d4efe1 EZ |
27340 | @item maint internal-error @r{[}@var{message-text}@r{]} |
27341 | @itemx maint internal-warning @r{[}@var{message-text}@r{]} | |
8d30a00d AC |
27342 | Cause @value{GDBN} to call the internal function @code{internal_error} |
27343 | or @code{internal_warning} and hence behave as though an internal error | |
27344 | or internal warning has been detected. In addition to reporting the | |
27345 | internal problem, these functions give the user the opportunity to | |
27346 | either quit @value{GDBN} or create a core file of the current | |
27347 | @value{GDBN} session. | |
27348 | ||
09d4efe1 EZ |
27349 | These commands take an optional parameter @var{message-text} that is |
27350 | used as the text of the error or warning message. | |
27351 | ||
d3e8051b | 27352 | Here's an example of using @code{internal-error}: |
09d4efe1 | 27353 | |
8d30a00d | 27354 | @smallexample |
f7dc1244 | 27355 | (@value{GDBP}) @kbd{maint internal-error testing, 1, 2} |
8d30a00d AC |
27356 | @dots{}/maint.c:121: internal-error: testing, 1, 2 |
27357 | A problem internal to GDB has been detected. Further | |
27358 | debugging may prove unreliable. | |
27359 | Quit this debugging session? (y or n) @kbd{n} | |
27360 | Create a core file? (y or n) @kbd{n} | |
f7dc1244 | 27361 | (@value{GDBP}) |
8d30a00d AC |
27362 | @end smallexample |
27363 | ||
3c16cced PA |
27364 | @cindex @value{GDBN} internal error |
27365 | @cindex internal errors, control of @value{GDBN} behavior | |
27366 | ||
27367 | @kindex maint set internal-error | |
27368 | @kindex maint show internal-error | |
27369 | @kindex maint set internal-warning | |
27370 | @kindex maint show internal-warning | |
27371 | @item maint set internal-error @var{action} [ask|yes|no] | |
27372 | @itemx maint show internal-error @var{action} | |
27373 | @itemx maint set internal-warning @var{action} [ask|yes|no] | |
27374 | @itemx maint show internal-warning @var{action} | |
27375 | When @value{GDBN} reports an internal problem (error or warning) it | |
27376 | gives the user the opportunity to both quit @value{GDBN} and create a | |
27377 | core file of the current @value{GDBN} session. These commands let you | |
27378 | override the default behaviour for each particular @var{action}, | |
27379 | described in the table below. | |
27380 | ||
27381 | @table @samp | |
27382 | @item quit | |
27383 | You can specify that @value{GDBN} should always (yes) or never (no) | |
27384 | quit. The default is to ask the user what to do. | |
27385 | ||
27386 | @item corefile | |
27387 | You can specify that @value{GDBN} should always (yes) or never (no) | |
27388 | create a core file. The default is to ask the user what to do. | |
27389 | @end table | |
27390 | ||
09d4efe1 EZ |
27391 | @kindex maint packet |
27392 | @item maint packet @var{text} | |
27393 | If @value{GDBN} is talking to an inferior via the serial protocol, | |
27394 | then this command sends the string @var{text} to the inferior, and | |
27395 | displays the response packet. @value{GDBN} supplies the initial | |
27396 | @samp{$} character, the terminating @samp{#} character, and the | |
27397 | checksum. | |
27398 | ||
27399 | @kindex maint print architecture | |
27400 | @item maint print architecture @r{[}@var{file}@r{]} | |
27401 | Print the entire architecture configuration. The optional argument | |
27402 | @var{file} names the file where the output goes. | |
8d30a00d | 27403 | |
81adfced DJ |
27404 | @kindex maint print c-tdesc |
27405 | @item maint print c-tdesc | |
27406 | Print the current target description (@pxref{Target Descriptions}) as | |
27407 | a C source file. The created source file can be used in @value{GDBN} | |
27408 | when an XML parser is not available to parse the description. | |
27409 | ||
00905d52 AC |
27410 | @kindex maint print dummy-frames |
27411 | @item maint print dummy-frames | |
00905d52 AC |
27412 | Prints the contents of @value{GDBN}'s internal dummy-frame stack. |
27413 | ||
27414 | @smallexample | |
f7dc1244 | 27415 | (@value{GDBP}) @kbd{b add} |
00905d52 | 27416 | @dots{} |
f7dc1244 | 27417 | (@value{GDBP}) @kbd{print add(2,3)} |
00905d52 AC |
27418 | Breakpoint 2, add (a=2, b=3) at @dots{} |
27419 | 58 return (a + b); | |
27420 | The program being debugged stopped while in a function called from GDB. | |
27421 | @dots{} | |
f7dc1244 | 27422 | (@value{GDBP}) @kbd{maint print dummy-frames} |
00905d52 AC |
27423 | 0x1a57c80: pc=0x01014068 fp=0x0200bddc sp=0x0200bdd6 |
27424 | top=0x0200bdd4 id=@{stack=0x200bddc,code=0x101405c@} | |
27425 | call_lo=0x01014000 call_hi=0x01014001 | |
f7dc1244 | 27426 | (@value{GDBP}) |
00905d52 AC |
27427 | @end smallexample |
27428 | ||
27429 | Takes an optional file parameter. | |
27430 | ||
0680b120 AC |
27431 | @kindex maint print registers |
27432 | @kindex maint print raw-registers | |
27433 | @kindex maint print cooked-registers | |
617073a9 | 27434 | @kindex maint print register-groups |
09d4efe1 EZ |
27435 | @item maint print registers @r{[}@var{file}@r{]} |
27436 | @itemx maint print raw-registers @r{[}@var{file}@r{]} | |
27437 | @itemx maint print cooked-registers @r{[}@var{file}@r{]} | |
27438 | @itemx maint print register-groups @r{[}@var{file}@r{]} | |
0680b120 AC |
27439 | Print @value{GDBN}'s internal register data structures. |
27440 | ||
617073a9 AC |
27441 | The command @code{maint print raw-registers} includes the contents of |
27442 | the raw register cache; the command @code{maint print cooked-registers} | |
27443 | includes the (cooked) value of all registers; and the command | |
27444 | @code{maint print register-groups} includes the groups that each | |
27445 | register is a member of. @xref{Registers,, Registers, gdbint, | |
27446 | @value{GDBN} Internals}. | |
0680b120 | 27447 | |
09d4efe1 EZ |
27448 | These commands take an optional parameter, a file name to which to |
27449 | write the information. | |
0680b120 | 27450 | |
617073a9 | 27451 | @kindex maint print reggroups |
09d4efe1 EZ |
27452 | @item maint print reggroups @r{[}@var{file}@r{]} |
27453 | Print @value{GDBN}'s internal register group data structures. The | |
27454 | optional argument @var{file} tells to what file to write the | |
27455 | information. | |
617073a9 | 27456 | |
09d4efe1 | 27457 | The register groups info looks like this: |
617073a9 AC |
27458 | |
27459 | @smallexample | |
f7dc1244 | 27460 | (@value{GDBP}) @kbd{maint print reggroups} |
b383017d RM |
27461 | Group Type |
27462 | general user | |
27463 | float user | |
27464 | all user | |
27465 | vector user | |
27466 | system user | |
27467 | save internal | |
27468 | restore internal | |
617073a9 AC |
27469 | @end smallexample |
27470 | ||
09d4efe1 EZ |
27471 | @kindex flushregs |
27472 | @item flushregs | |
27473 | This command forces @value{GDBN} to flush its internal register cache. | |
27474 | ||
27475 | @kindex maint print objfiles | |
27476 | @cindex info for known object files | |
27477 | @item maint print objfiles | |
27478 | Print a dump of all known object files. For each object file, this | |
27479 | command prints its name, address in memory, and all of its psymtabs | |
27480 | and symtabs. | |
27481 | ||
27482 | @kindex maint print statistics | |
27483 | @cindex bcache statistics | |
27484 | @item maint print statistics | |
27485 | This command prints, for each object file in the program, various data | |
27486 | about that object file followed by the byte cache (@dfn{bcache}) | |
27487 | statistics for the object file. The objfile data includes the number | |
d3e8051b | 27488 | of minimal, partial, full, and stabs symbols, the number of types |
09d4efe1 EZ |
27489 | defined by the objfile, the number of as yet unexpanded psym tables, |
27490 | the number of line tables and string tables, and the amount of memory | |
27491 | used by the various tables. The bcache statistics include the counts, | |
27492 | sizes, and counts of duplicates of all and unique objects, max, | |
27493 | average, and median entry size, total memory used and its overhead and | |
27494 | savings, and various measures of the hash table size and chain | |
27495 | lengths. | |
27496 | ||
c7ba131e JB |
27497 | @kindex maint print target-stack |
27498 | @cindex target stack description | |
27499 | @item maint print target-stack | |
27500 | A @dfn{target} is an interface between the debugger and a particular | |
27501 | kind of file or process. Targets can be stacked in @dfn{strata}, | |
27502 | so that more than one target can potentially respond to a request. | |
27503 | In particular, memory accesses will walk down the stack of targets | |
27504 | until they find a target that is interested in handling that particular | |
27505 | address. | |
27506 | ||
27507 | This command prints a short description of each layer that was pushed on | |
27508 | the @dfn{target stack}, starting from the top layer down to the bottom one. | |
27509 | ||
09d4efe1 EZ |
27510 | @kindex maint print type |
27511 | @cindex type chain of a data type | |
27512 | @item maint print type @var{expr} | |
27513 | Print the type chain for a type specified by @var{expr}. The argument | |
27514 | can be either a type name or a symbol. If it is a symbol, the type of | |
27515 | that symbol is described. The type chain produced by this command is | |
27516 | a recursive definition of the data type as stored in @value{GDBN}'s | |
27517 | data structures, including its flags and contained types. | |
27518 | ||
27519 | @kindex maint set dwarf2 max-cache-age | |
27520 | @kindex maint show dwarf2 max-cache-age | |
27521 | @item maint set dwarf2 max-cache-age | |
27522 | @itemx maint show dwarf2 max-cache-age | |
27523 | Control the DWARF 2 compilation unit cache. | |
27524 | ||
27525 | @cindex DWARF 2 compilation units cache | |
27526 | In object files with inter-compilation-unit references, such as those | |
27527 | produced by the GCC option @samp{-feliminate-dwarf2-dups}, the DWARF 2 | |
27528 | reader needs to frequently refer to previously read compilation units. | |
27529 | This setting controls how long a compilation unit will remain in the | |
27530 | cache if it is not referenced. A higher limit means that cached | |
27531 | compilation units will be stored in memory longer, and more total | |
27532 | memory will be used. Setting it to zero disables caching, which will | |
27533 | slow down @value{GDBN} startup, but reduce memory consumption. | |
27534 | ||
e7ba9c65 DJ |
27535 | @kindex maint set profile |
27536 | @kindex maint show profile | |
27537 | @cindex profiling GDB | |
27538 | @item maint set profile | |
27539 | @itemx maint show profile | |
27540 | Control profiling of @value{GDBN}. | |
27541 | ||
27542 | Profiling will be disabled until you use the @samp{maint set profile} | |
27543 | command to enable it. When you enable profiling, the system will begin | |
27544 | collecting timing and execution count data; when you disable profiling or | |
27545 | exit @value{GDBN}, the results will be written to a log file. Remember that | |
27546 | if you use profiling, @value{GDBN} will overwrite the profiling log file | |
27547 | (often called @file{gmon.out}). If you have a record of important profiling | |
27548 | data in a @file{gmon.out} file, be sure to move it to a safe location. | |
27549 | ||
27550 | Configuring with @samp{--enable-profiling} arranges for @value{GDBN} to be | |
b383017d | 27551 | compiled with the @samp{-pg} compiler option. |
e7ba9c65 | 27552 | |
cbe54154 PA |
27553 | @kindex maint set show-debug-regs |
27554 | @kindex maint show show-debug-regs | |
eac35c4e | 27555 | @cindex hardware debug registers |
cbe54154 PA |
27556 | @item maint set show-debug-regs |
27557 | @itemx maint show show-debug-regs | |
eac35c4e | 27558 | Control whether to show variables that mirror the hardware debug |
09d4efe1 | 27559 | registers. Use @code{ON} to enable, @code{OFF} to disable. If |
3f94c067 | 27560 | enabled, the debug registers values are shown when @value{GDBN} inserts or |
09d4efe1 EZ |
27561 | removes a hardware breakpoint or watchpoint, and when the inferior |
27562 | triggers a hardware-assisted breakpoint or watchpoint. | |
27563 | ||
27564 | @kindex maint space | |
27565 | @cindex memory used by commands | |
27566 | @item maint space | |
27567 | Control whether to display memory usage for each command. If set to a | |
27568 | nonzero value, @value{GDBN} will display how much memory each command | |
27569 | took, following the command's own output. This can also be requested | |
27570 | by invoking @value{GDBN} with the @option{--statistics} command-line | |
27571 | switch (@pxref{Mode Options}). | |
27572 | ||
27573 | @kindex maint time | |
27574 | @cindex time of command execution | |
27575 | @item maint time | |
27576 | Control whether to display the execution time for each command. If | |
27577 | set to a nonzero value, @value{GDBN} will display how much time it | |
27578 | took to execute each command, following the command's own output. | |
e2b7ddea VP |
27579 | The time is not printed for the commands that run the target, since |
27580 | there's no mechanism currently to compute how much time was spend | |
27581 | by @value{GDBN} and how much time was spend by the program been debugged. | |
27582 | it's not possibly currently | |
09d4efe1 EZ |
27583 | This can also be requested by invoking @value{GDBN} with the |
27584 | @option{--statistics} command-line switch (@pxref{Mode Options}). | |
27585 | ||
27586 | @kindex maint translate-address | |
27587 | @item maint translate-address @r{[}@var{section}@r{]} @var{addr} | |
27588 | Find the symbol stored at the location specified by the address | |
27589 | @var{addr} and an optional section name @var{section}. If found, | |
27590 | @value{GDBN} prints the name of the closest symbol and an offset from | |
27591 | the symbol's location to the specified address. This is similar to | |
27592 | the @code{info address} command (@pxref{Symbols}), except that this | |
27593 | command also allows to find symbols in other sections. | |
ae038cb0 | 27594 | |
c14c28ba PP |
27595 | If section was not specified, the section in which the symbol was found |
27596 | is also printed. For dynamically linked executables, the name of | |
27597 | executable or shared library containing the symbol is printed as well. | |
27598 | ||
8e04817f | 27599 | @end table |
c906108c | 27600 | |
9c16f35a EZ |
27601 | The following command is useful for non-interactive invocations of |
27602 | @value{GDBN}, such as in the test suite. | |
27603 | ||
27604 | @table @code | |
27605 | @item set watchdog @var{nsec} | |
27606 | @kindex set watchdog | |
27607 | @cindex watchdog timer | |
27608 | @cindex timeout for commands | |
27609 | Set the maximum number of seconds @value{GDBN} will wait for the | |
27610 | target operation to finish. If this time expires, @value{GDBN} | |
27611 | reports and error and the command is aborted. | |
27612 | ||
27613 | @item show watchdog | |
27614 | Show the current setting of the target wait timeout. | |
27615 | @end table | |
c906108c | 27616 | |
e0ce93ac | 27617 | @node Remote Protocol |
8e04817f | 27618 | @appendix @value{GDBN} Remote Serial Protocol |
c906108c | 27619 | |
ee2d5c50 AC |
27620 | @menu |
27621 | * Overview:: | |
27622 | * Packets:: | |
27623 | * Stop Reply Packets:: | |
27624 | * General Query Packets:: | |
27625 | * Register Packet Format:: | |
9d29849a | 27626 | * Tracepoint Packets:: |
a6b151f1 | 27627 | * Host I/O Packets:: |
9a6253be | 27628 | * Interrupts:: |
8b23ecc4 SL |
27629 | * Notification Packets:: |
27630 | * Remote Non-Stop:: | |
a6f3e723 | 27631 | * Packet Acknowledgment:: |
ee2d5c50 | 27632 | * Examples:: |
79a6e687 | 27633 | * File-I/O Remote Protocol Extension:: |
cfa9d6d9 | 27634 | * Library List Format:: |
79a6e687 | 27635 | * Memory Map Format:: |
ee2d5c50 AC |
27636 | @end menu |
27637 | ||
27638 | @node Overview | |
27639 | @section Overview | |
27640 | ||
8e04817f AC |
27641 | There may be occasions when you need to know something about the |
27642 | protocol---for example, if there is only one serial port to your target | |
27643 | machine, you might want your program to do something special if it | |
27644 | recognizes a packet meant for @value{GDBN}. | |
c906108c | 27645 | |
d2c6833e | 27646 | In the examples below, @samp{->} and @samp{<-} are used to indicate |
bf06d120 | 27647 | transmitted and received data, respectively. |
c906108c | 27648 | |
8e04817f AC |
27649 | @cindex protocol, @value{GDBN} remote serial |
27650 | @cindex serial protocol, @value{GDBN} remote | |
27651 | @cindex remote serial protocol | |
8b23ecc4 SL |
27652 | All @value{GDBN} commands and responses (other than acknowledgments |
27653 | and notifications, see @ref{Notification Packets}) are sent as a | |
27654 | @var{packet}. A @var{packet} is introduced with the character | |
8e04817f AC |
27655 | @samp{$}, the actual @var{packet-data}, and the terminating character |
27656 | @samp{#} followed by a two-digit @var{checksum}: | |
c906108c | 27657 | |
474c8240 | 27658 | @smallexample |
8e04817f | 27659 | @code{$}@var{packet-data}@code{#}@var{checksum} |
474c8240 | 27660 | @end smallexample |
8e04817f | 27661 | @noindent |
c906108c | 27662 | |
8e04817f AC |
27663 | @cindex checksum, for @value{GDBN} remote |
27664 | @noindent | |
27665 | The two-digit @var{checksum} is computed as the modulo 256 sum of all | |
27666 | characters between the leading @samp{$} and the trailing @samp{#} (an | |
27667 | eight bit unsigned checksum). | |
c906108c | 27668 | |
8e04817f AC |
27669 | Implementors should note that prior to @value{GDBN} 5.0 the protocol |
27670 | specification also included an optional two-digit @var{sequence-id}: | |
c906108c | 27671 | |
474c8240 | 27672 | @smallexample |
8e04817f | 27673 | @code{$}@var{sequence-id}@code{:}@var{packet-data}@code{#}@var{checksum} |
474c8240 | 27674 | @end smallexample |
c906108c | 27675 | |
8e04817f AC |
27676 | @cindex sequence-id, for @value{GDBN} remote |
27677 | @noindent | |
27678 | That @var{sequence-id} was appended to the acknowledgment. @value{GDBN} | |
27679 | has never output @var{sequence-id}s. Stubs that handle packets added | |
27680 | since @value{GDBN} 5.0 must not accept @var{sequence-id}. | |
c906108c | 27681 | |
8e04817f AC |
27682 | When either the host or the target machine receives a packet, the first |
27683 | response expected is an acknowledgment: either @samp{+} (to indicate | |
27684 | the package was received correctly) or @samp{-} (to request | |
27685 | retransmission): | |
c906108c | 27686 | |
474c8240 | 27687 | @smallexample |
d2c6833e AC |
27688 | -> @code{$}@var{packet-data}@code{#}@var{checksum} |
27689 | <- @code{+} | |
474c8240 | 27690 | @end smallexample |
8e04817f | 27691 | @noindent |
53a5351d | 27692 | |
a6f3e723 SL |
27693 | The @samp{+}/@samp{-} acknowledgments can be disabled |
27694 | once a connection is established. | |
27695 | @xref{Packet Acknowledgment}, for details. | |
27696 | ||
8e04817f AC |
27697 | The host (@value{GDBN}) sends @var{command}s, and the target (the |
27698 | debugging stub incorporated in your program) sends a @var{response}. In | |
27699 | the case of step and continue @var{command}s, the response is only sent | |
8b23ecc4 SL |
27700 | when the operation has completed, and the target has again stopped all |
27701 | threads in all attached processes. This is the default all-stop mode | |
27702 | behavior, but the remote protocol also supports @value{GDBN}'s non-stop | |
27703 | execution mode; see @ref{Remote Non-Stop}, for details. | |
c906108c | 27704 | |
8e04817f AC |
27705 | @var{packet-data} consists of a sequence of characters with the |
27706 | exception of @samp{#} and @samp{$} (see @samp{X} packet for additional | |
27707 | exceptions). | |
c906108c | 27708 | |
ee2d5c50 | 27709 | @cindex remote protocol, field separator |
0876f84a | 27710 | Fields within the packet should be separated using @samp{,} @samp{;} or |
8e04817f | 27711 | @samp{:}. Except where otherwise noted all numbers are represented in |
ee2d5c50 | 27712 | @sc{hex} with leading zeros suppressed. |
c906108c | 27713 | |
8e04817f AC |
27714 | Implementors should note that prior to @value{GDBN} 5.0, the character |
27715 | @samp{:} could not appear as the third character in a packet (as it | |
27716 | would potentially conflict with the @var{sequence-id}). | |
c906108c | 27717 | |
0876f84a DJ |
27718 | @cindex remote protocol, binary data |
27719 | @anchor{Binary Data} | |
27720 | Binary data in most packets is encoded either as two hexadecimal | |
27721 | digits per byte of binary data. This allowed the traditional remote | |
27722 | protocol to work over connections which were only seven-bit clean. | |
27723 | Some packets designed more recently assume an eight-bit clean | |
27724 | connection, and use a more efficient encoding to send and receive | |
27725 | binary data. | |
27726 | ||
27727 | The binary data representation uses @code{7d} (@sc{ascii} @samp{@}}) | |
27728 | as an escape character. Any escaped byte is transmitted as the escape | |
27729 | character followed by the original character XORed with @code{0x20}. | |
27730 | For example, the byte @code{0x7d} would be transmitted as the two | |
27731 | bytes @code{0x7d 0x5d}. The bytes @code{0x23} (@sc{ascii} @samp{#}), | |
27732 | @code{0x24} (@sc{ascii} @samp{$}), and @code{0x7d} (@sc{ascii} | |
27733 | @samp{@}}) must always be escaped. Responses sent by the stub | |
27734 | must also escape @code{0x2a} (@sc{ascii} @samp{*}), so that it | |
27735 | is not interpreted as the start of a run-length encoded sequence | |
27736 | (described next). | |
27737 | ||
1d3811f6 DJ |
27738 | Response @var{data} can be run-length encoded to save space. |
27739 | Run-length encoding replaces runs of identical characters with one | |
27740 | instance of the repeated character, followed by a @samp{*} and a | |
27741 | repeat count. The repeat count is itself sent encoded, to avoid | |
27742 | binary characters in @var{data}: a value of @var{n} is sent as | |
27743 | @code{@var{n}+29}. For a repeat count greater or equal to 3, this | |
27744 | produces a printable @sc{ascii} character, e.g.@: a space (@sc{ascii} | |
27745 | code 32) for a repeat count of 3. (This is because run-length | |
27746 | encoding starts to win for counts 3 or more.) Thus, for example, | |
27747 | @samp{0* } is a run-length encoding of ``0000'': the space character | |
27748 | after @samp{*} means repeat the leading @code{0} @w{@code{32 - 29 = | |
27749 | 3}} more times. | |
27750 | ||
27751 | The printable characters @samp{#} and @samp{$} or with a numeric value | |
27752 | greater than 126 must not be used. Runs of six repeats (@samp{#}) or | |
27753 | seven repeats (@samp{$}) can be expanded using a repeat count of only | |
27754 | five (@samp{"}). For example, @samp{00000000} can be encoded as | |
27755 | @samp{0*"00}. | |
c906108c | 27756 | |
8e04817f AC |
27757 | The error response returned for some packets includes a two character |
27758 | error number. That number is not well defined. | |
c906108c | 27759 | |
f8da2bff | 27760 | @cindex empty response, for unsupported packets |
8e04817f AC |
27761 | For any @var{command} not supported by the stub, an empty response |
27762 | (@samp{$#00}) should be returned. That way it is possible to extend the | |
27763 | protocol. A newer @value{GDBN} can tell if a packet is supported based | |
27764 | on that response. | |
c906108c | 27765 | |
b383017d RM |
27766 | A stub is required to support the @samp{g}, @samp{G}, @samp{m}, @samp{M}, |
27767 | @samp{c}, and @samp{s} @var{command}s. All other @var{command}s are | |
8e04817f | 27768 | optional. |
c906108c | 27769 | |
ee2d5c50 AC |
27770 | @node Packets |
27771 | @section Packets | |
27772 | ||
27773 | The following table provides a complete list of all currently defined | |
27774 | @var{command}s and their corresponding response @var{data}. | |
79a6e687 | 27775 | @xref{File-I/O Remote Protocol Extension}, for details about the File |
9c16f35a | 27776 | I/O extension of the remote protocol. |
ee2d5c50 | 27777 | |
b8ff78ce JB |
27778 | Each packet's description has a template showing the packet's overall |
27779 | syntax, followed by an explanation of the packet's meaning. We | |
27780 | include spaces in some of the templates for clarity; these are not | |
27781 | part of the packet's syntax. No @value{GDBN} packet uses spaces to | |
27782 | separate its components. For example, a template like @samp{foo | |
27783 | @var{bar} @var{baz}} describes a packet beginning with the three ASCII | |
27784 | bytes @samp{foo}, followed by a @var{bar}, followed directly by a | |
3f94c067 | 27785 | @var{baz}. @value{GDBN} does not transmit a space character between the |
b8ff78ce JB |
27786 | @samp{foo} and the @var{bar}, or between the @var{bar} and the |
27787 | @var{baz}. | |
27788 | ||
b90a069a SL |
27789 | @cindex @var{thread-id}, in remote protocol |
27790 | @anchor{thread-id syntax} | |
27791 | Several packets and replies include a @var{thread-id} field to identify | |
27792 | a thread. Normally these are positive numbers with a target-specific | |
27793 | interpretation, formatted as big-endian hex strings. A @var{thread-id} | |
27794 | can also be a literal @samp{-1} to indicate all threads, or @samp{0} to | |
27795 | pick any thread. | |
27796 | ||
27797 | In addition, the remote protocol supports a multiprocess feature in | |
27798 | which the @var{thread-id} syntax is extended to optionally include both | |
27799 | process and thread ID fields, as @samp{p@var{pid}.@var{tid}}. | |
27800 | The @var{pid} (process) and @var{tid} (thread) components each have the | |
27801 | format described above: a positive number with target-specific | |
27802 | interpretation formatted as a big-endian hex string, literal @samp{-1} | |
27803 | to indicate all processes or threads (respectively), or @samp{0} to | |
27804 | indicate an arbitrary process or thread. Specifying just a process, as | |
27805 | @samp{p@var{pid}}, is equivalent to @samp{p@var{pid}.-1}. It is an | |
27806 | error to specify all processes but a specific thread, such as | |
27807 | @samp{p-1.@var{tid}}. Note that the @samp{p} prefix is @emph{not} used | |
27808 | for those packets and replies explicitly documented to include a process | |
27809 | ID, rather than a @var{thread-id}. | |
27810 | ||
27811 | The multiprocess @var{thread-id} syntax extensions are only used if both | |
27812 | @value{GDBN} and the stub report support for the @samp{multiprocess} | |
27813 | feature using @samp{qSupported}. @xref{multiprocess extensions}, for | |
27814 | more information. | |
27815 | ||
8ffe2530 JB |
27816 | Note that all packet forms beginning with an upper- or lower-case |
27817 | letter, other than those described here, are reserved for future use. | |
27818 | ||
b8ff78ce | 27819 | Here are the packet descriptions. |
ee2d5c50 | 27820 | |
b8ff78ce | 27821 | @table @samp |
ee2d5c50 | 27822 | |
b8ff78ce JB |
27823 | @item ! |
27824 | @cindex @samp{!} packet | |
2d717e4f | 27825 | @anchor{extended mode} |
8e04817f AC |
27826 | Enable extended mode. In extended mode, the remote server is made |
27827 | persistent. The @samp{R} packet is used to restart the program being | |
27828 | debugged. | |
ee2d5c50 AC |
27829 | |
27830 | Reply: | |
27831 | @table @samp | |
27832 | @item OK | |
8e04817f | 27833 | The remote target both supports and has enabled extended mode. |
ee2d5c50 | 27834 | @end table |
c906108c | 27835 | |
b8ff78ce JB |
27836 | @item ? |
27837 | @cindex @samp{?} packet | |
ee2d5c50 | 27838 | Indicate the reason the target halted. The reply is the same as for |
8b23ecc4 SL |
27839 | step and continue. This packet has a special interpretation when the |
27840 | target is in non-stop mode; see @ref{Remote Non-Stop}. | |
c906108c | 27841 | |
ee2d5c50 AC |
27842 | Reply: |
27843 | @xref{Stop Reply Packets}, for the reply specifications. | |
27844 | ||
b8ff78ce JB |
27845 | @item A @var{arglen},@var{argnum},@var{arg},@dots{} |
27846 | @cindex @samp{A} packet | |
27847 | Initialized @code{argv[]} array passed into program. @var{arglen} | |
27848 | specifies the number of bytes in the hex encoded byte stream | |
27849 | @var{arg}. See @code{gdbserver} for more details. | |
ee2d5c50 AC |
27850 | |
27851 | Reply: | |
27852 | @table @samp | |
27853 | @item OK | |
b8ff78ce JB |
27854 | The arguments were set. |
27855 | @item E @var{NN} | |
27856 | An error occurred. | |
ee2d5c50 AC |
27857 | @end table |
27858 | ||
b8ff78ce JB |
27859 | @item b @var{baud} |
27860 | @cindex @samp{b} packet | |
27861 | (Don't use this packet; its behavior is not well-defined.) | |
ee2d5c50 AC |
27862 | Change the serial line speed to @var{baud}. |
27863 | ||
27864 | JTC: @emph{When does the transport layer state change? When it's | |
27865 | received, or after the ACK is transmitted. In either case, there are | |
27866 | problems if the command or the acknowledgment packet is dropped.} | |
27867 | ||
27868 | Stan: @emph{If people really wanted to add something like this, and get | |
27869 | it working for the first time, they ought to modify ser-unix.c to send | |
27870 | some kind of out-of-band message to a specially-setup stub and have the | |
27871 | switch happen "in between" packets, so that from remote protocol's point | |
27872 | of view, nothing actually happened.} | |
27873 | ||
b8ff78ce JB |
27874 | @item B @var{addr},@var{mode} |
27875 | @cindex @samp{B} packet | |
8e04817f | 27876 | Set (@var{mode} is @samp{S}) or clear (@var{mode} is @samp{C}) a |
2f870471 AC |
27877 | breakpoint at @var{addr}. |
27878 | ||
b8ff78ce | 27879 | Don't use this packet. Use the @samp{Z} and @samp{z} packets instead |
2f870471 | 27880 | (@pxref{insert breakpoint or watchpoint packet}). |
c906108c | 27881 | |
bacec72f | 27882 | @cindex @samp{bc} packet |
0d772ac9 MS |
27883 | @anchor{bc} |
27884 | @item bc | |
bacec72f MS |
27885 | Backward continue. Execute the target system in reverse. No parameter. |
27886 | @xref{Reverse Execution}, for more information. | |
27887 | ||
27888 | Reply: | |
27889 | @xref{Stop Reply Packets}, for the reply specifications. | |
27890 | ||
bacec72f | 27891 | @cindex @samp{bs} packet |
0d772ac9 MS |
27892 | @anchor{bs} |
27893 | @item bs | |
bacec72f MS |
27894 | Backward single step. Execute one instruction in reverse. No parameter. |
27895 | @xref{Reverse Execution}, for more information. | |
27896 | ||
27897 | Reply: | |
27898 | @xref{Stop Reply Packets}, for the reply specifications. | |
27899 | ||
4f553f88 | 27900 | @item c @r{[}@var{addr}@r{]} |
b8ff78ce JB |
27901 | @cindex @samp{c} packet |
27902 | Continue. @var{addr} is address to resume. If @var{addr} is omitted, | |
27903 | resume at current address. | |
c906108c | 27904 | |
ee2d5c50 AC |
27905 | Reply: |
27906 | @xref{Stop Reply Packets}, for the reply specifications. | |
27907 | ||
4f553f88 | 27908 | @item C @var{sig}@r{[};@var{addr}@r{]} |
b8ff78ce | 27909 | @cindex @samp{C} packet |
8e04817f | 27910 | Continue with signal @var{sig} (hex signal number). If |
b8ff78ce | 27911 | @samp{;@var{addr}} is omitted, resume at same address. |
c906108c | 27912 | |
ee2d5c50 AC |
27913 | Reply: |
27914 | @xref{Stop Reply Packets}, for the reply specifications. | |
c906108c | 27915 | |
b8ff78ce JB |
27916 | @item d |
27917 | @cindex @samp{d} packet | |
ee2d5c50 AC |
27918 | Toggle debug flag. |
27919 | ||
b8ff78ce JB |
27920 | Don't use this packet; instead, define a general set packet |
27921 | (@pxref{General Query Packets}). | |
ee2d5c50 | 27922 | |
b8ff78ce | 27923 | @item D |
b90a069a | 27924 | @itemx D;@var{pid} |
b8ff78ce | 27925 | @cindex @samp{D} packet |
b90a069a SL |
27926 | The first form of the packet is used to detach @value{GDBN} from the |
27927 | remote system. It is sent to the remote target | |
07f31aa6 | 27928 | before @value{GDBN} disconnects via the @code{detach} command. |
ee2d5c50 | 27929 | |
b90a069a SL |
27930 | The second form, including a process ID, is used when multiprocess |
27931 | protocol extensions are enabled (@pxref{multiprocess extensions}), to | |
27932 | detach only a specific process. The @var{pid} is specified as a | |
27933 | big-endian hex string. | |
27934 | ||
ee2d5c50 AC |
27935 | Reply: |
27936 | @table @samp | |
10fac096 NW |
27937 | @item OK |
27938 | for success | |
b8ff78ce | 27939 | @item E @var{NN} |
10fac096 | 27940 | for an error |
ee2d5c50 | 27941 | @end table |
c906108c | 27942 | |
b8ff78ce JB |
27943 | @item F @var{RC},@var{EE},@var{CF};@var{XX} |
27944 | @cindex @samp{F} packet | |
27945 | A reply from @value{GDBN} to an @samp{F} packet sent by the target. | |
27946 | This is part of the File-I/O protocol extension. @xref{File-I/O | |
79a6e687 | 27947 | Remote Protocol Extension}, for the specification. |
ee2d5c50 | 27948 | |
b8ff78ce | 27949 | @item g |
ee2d5c50 | 27950 | @anchor{read registers packet} |
b8ff78ce | 27951 | @cindex @samp{g} packet |
ee2d5c50 AC |
27952 | Read general registers. |
27953 | ||
27954 | Reply: | |
27955 | @table @samp | |
27956 | @item @var{XX@dots{}} | |
8e04817f AC |
27957 | Each byte of register data is described by two hex digits. The bytes |
27958 | with the register are transmitted in target byte order. The size of | |
b8ff78ce | 27959 | each register and their position within the @samp{g} packet are |
4a9bb1df UW |
27960 | determined by the @value{GDBN} internal gdbarch functions |
27961 | @code{DEPRECATED_REGISTER_RAW_SIZE} and @code{gdbarch_register_name}. The | |
b8ff78ce JB |
27962 | specification of several standard @samp{g} packets is specified below. |
27963 | @item E @var{NN} | |
ee2d5c50 AC |
27964 | for an error. |
27965 | @end table | |
c906108c | 27966 | |
b8ff78ce JB |
27967 | @item G @var{XX@dots{}} |
27968 | @cindex @samp{G} packet | |
27969 | Write general registers. @xref{read registers packet}, for a | |
27970 | description of the @var{XX@dots{}} data. | |
ee2d5c50 AC |
27971 | |
27972 | Reply: | |
27973 | @table @samp | |
27974 | @item OK | |
27975 | for success | |
b8ff78ce | 27976 | @item E @var{NN} |
ee2d5c50 AC |
27977 | for an error |
27978 | @end table | |
27979 | ||
b90a069a | 27980 | @item H @var{c} @var{thread-id} |
b8ff78ce | 27981 | @cindex @samp{H} packet |
8e04817f | 27982 | Set thread for subsequent operations (@samp{m}, @samp{M}, @samp{g}, |
ee2d5c50 AC |
27983 | @samp{G}, et.al.). @var{c} depends on the operation to be performed: it |
27984 | should be @samp{c} for step and continue operations, @samp{g} for other | |
b90a069a SL |
27985 | operations. The thread designator @var{thread-id} has the format and |
27986 | interpretation described in @ref{thread-id syntax}. | |
ee2d5c50 AC |
27987 | |
27988 | Reply: | |
27989 | @table @samp | |
27990 | @item OK | |
27991 | for success | |
b8ff78ce | 27992 | @item E @var{NN} |
ee2d5c50 AC |
27993 | for an error |
27994 | @end table | |
c906108c | 27995 | |
8e04817f AC |
27996 | @c FIXME: JTC: |
27997 | @c 'H': How restrictive (or permissive) is the thread model. If a | |
27998 | @c thread is selected and stopped, are other threads allowed | |
27999 | @c to continue to execute? As I mentioned above, I think the | |
28000 | @c semantics of each command when a thread is selected must be | |
28001 | @c described. For example: | |
28002 | @c | |
28003 | @c 'g': If the stub supports threads and a specific thread is | |
28004 | @c selected, returns the register block from that thread; | |
28005 | @c otherwise returns current registers. | |
28006 | @c | |
28007 | @c 'G' If the stub supports threads and a specific thread is | |
28008 | @c selected, sets the registers of the register block of | |
28009 | @c that thread; otherwise sets current registers. | |
c906108c | 28010 | |
b8ff78ce | 28011 | @item i @r{[}@var{addr}@r{[},@var{nnn}@r{]]} |
ee2d5c50 | 28012 | @anchor{cycle step packet} |
b8ff78ce JB |
28013 | @cindex @samp{i} packet |
28014 | Step the remote target by a single clock cycle. If @samp{,@var{nnn}} is | |
8e04817f AC |
28015 | present, cycle step @var{nnn} cycles. If @var{addr} is present, cycle |
28016 | step starting at that address. | |
c906108c | 28017 | |
b8ff78ce JB |
28018 | @item I |
28019 | @cindex @samp{I} packet | |
28020 | Signal, then cycle step. @xref{step with signal packet}. @xref{cycle | |
28021 | step packet}. | |
ee2d5c50 | 28022 | |
b8ff78ce JB |
28023 | @item k |
28024 | @cindex @samp{k} packet | |
28025 | Kill request. | |
c906108c | 28026 | |
ac282366 | 28027 | FIXME: @emph{There is no description of how to operate when a specific |
ee2d5c50 AC |
28028 | thread context has been selected (i.e.@: does 'k' kill only that |
28029 | thread?)}. | |
c906108c | 28030 | |
b8ff78ce JB |
28031 | @item m @var{addr},@var{length} |
28032 | @cindex @samp{m} packet | |
8e04817f | 28033 | Read @var{length} bytes of memory starting at address @var{addr}. |
fb031cdf JB |
28034 | Note that @var{addr} may not be aligned to any particular boundary. |
28035 | ||
28036 | The stub need not use any particular size or alignment when gathering | |
28037 | data from memory for the response; even if @var{addr} is word-aligned | |
28038 | and @var{length} is a multiple of the word size, the stub is free to | |
28039 | use byte accesses, or not. For this reason, this packet may not be | |
28040 | suitable for accessing memory-mapped I/O devices. | |
c43c5473 JB |
28041 | @cindex alignment of remote memory accesses |
28042 | @cindex size of remote memory accesses | |
28043 | @cindex memory, alignment and size of remote accesses | |
c906108c | 28044 | |
ee2d5c50 AC |
28045 | Reply: |
28046 | @table @samp | |
28047 | @item @var{XX@dots{}} | |
599b237a | 28048 | Memory contents; each byte is transmitted as a two-digit hexadecimal |
b8ff78ce JB |
28049 | number. The reply may contain fewer bytes than requested if the |
28050 | server was able to read only part of the region of memory. | |
28051 | @item E @var{NN} | |
ee2d5c50 AC |
28052 | @var{NN} is errno |
28053 | @end table | |
28054 | ||
b8ff78ce JB |
28055 | @item M @var{addr},@var{length}:@var{XX@dots{}} |
28056 | @cindex @samp{M} packet | |
8e04817f | 28057 | Write @var{length} bytes of memory starting at address @var{addr}. |
b8ff78ce | 28058 | @var{XX@dots{}} is the data; each byte is transmitted as a two-digit |
599b237a | 28059 | hexadecimal number. |
ee2d5c50 AC |
28060 | |
28061 | Reply: | |
28062 | @table @samp | |
28063 | @item OK | |
28064 | for success | |
b8ff78ce | 28065 | @item E @var{NN} |
8e04817f AC |
28066 | for an error (this includes the case where only part of the data was |
28067 | written). | |
ee2d5c50 | 28068 | @end table |
c906108c | 28069 | |
b8ff78ce JB |
28070 | @item p @var{n} |
28071 | @cindex @samp{p} packet | |
28072 | Read the value of register @var{n}; @var{n} is in hex. | |
2e868123 AC |
28073 | @xref{read registers packet}, for a description of how the returned |
28074 | register value is encoded. | |
ee2d5c50 AC |
28075 | |
28076 | Reply: | |
28077 | @table @samp | |
2e868123 AC |
28078 | @item @var{XX@dots{}} |
28079 | the register's value | |
b8ff78ce | 28080 | @item E @var{NN} |
2e868123 AC |
28081 | for an error |
28082 | @item | |
28083 | Indicating an unrecognized @var{query}. | |
ee2d5c50 AC |
28084 | @end table |
28085 | ||
b8ff78ce | 28086 | @item P @var{n@dots{}}=@var{r@dots{}} |
ee2d5c50 | 28087 | @anchor{write register packet} |
b8ff78ce JB |
28088 | @cindex @samp{P} packet |
28089 | Write register @var{n@dots{}} with value @var{r@dots{}}. The register | |
599b237a | 28090 | number @var{n} is in hexadecimal, and @var{r@dots{}} contains two hex |
8e04817f | 28091 | digits for each byte in the register (target byte order). |
c906108c | 28092 | |
ee2d5c50 AC |
28093 | Reply: |
28094 | @table @samp | |
28095 | @item OK | |
28096 | for success | |
b8ff78ce | 28097 | @item E @var{NN} |
ee2d5c50 AC |
28098 | for an error |
28099 | @end table | |
28100 | ||
5f3bebba JB |
28101 | @item q @var{name} @var{params}@dots{} |
28102 | @itemx Q @var{name} @var{params}@dots{} | |
b8ff78ce | 28103 | @cindex @samp{q} packet |
b8ff78ce | 28104 | @cindex @samp{Q} packet |
5f3bebba JB |
28105 | General query (@samp{q}) and set (@samp{Q}). These packets are |
28106 | described fully in @ref{General Query Packets}. | |
c906108c | 28107 | |
b8ff78ce JB |
28108 | @item r |
28109 | @cindex @samp{r} packet | |
8e04817f | 28110 | Reset the entire system. |
c906108c | 28111 | |
b8ff78ce | 28112 | Don't use this packet; use the @samp{R} packet instead. |
ee2d5c50 | 28113 | |
b8ff78ce JB |
28114 | @item R @var{XX} |
28115 | @cindex @samp{R} packet | |
8e04817f | 28116 | Restart the program being debugged. @var{XX}, while needed, is ignored. |
2d717e4f | 28117 | This packet is only available in extended mode (@pxref{extended mode}). |
ee2d5c50 | 28118 | |
8e04817f | 28119 | The @samp{R} packet has no reply. |
ee2d5c50 | 28120 | |
4f553f88 | 28121 | @item s @r{[}@var{addr}@r{]} |
b8ff78ce JB |
28122 | @cindex @samp{s} packet |
28123 | Single step. @var{addr} is the address at which to resume. If | |
28124 | @var{addr} is omitted, resume at same address. | |
c906108c | 28125 | |
ee2d5c50 AC |
28126 | Reply: |
28127 | @xref{Stop Reply Packets}, for the reply specifications. | |
28128 | ||
4f553f88 | 28129 | @item S @var{sig}@r{[};@var{addr}@r{]} |
ee2d5c50 | 28130 | @anchor{step with signal packet} |
b8ff78ce JB |
28131 | @cindex @samp{S} packet |
28132 | Step with signal. This is analogous to the @samp{C} packet, but | |
28133 | requests a single-step, rather than a normal resumption of execution. | |
c906108c | 28134 | |
ee2d5c50 AC |
28135 | Reply: |
28136 | @xref{Stop Reply Packets}, for the reply specifications. | |
28137 | ||
b8ff78ce JB |
28138 | @item t @var{addr}:@var{PP},@var{MM} |
28139 | @cindex @samp{t} packet | |
8e04817f | 28140 | Search backwards starting at address @var{addr} for a match with pattern |
ee2d5c50 AC |
28141 | @var{PP} and mask @var{MM}. @var{PP} and @var{MM} are 4 bytes. |
28142 | @var{addr} must be at least 3 digits. | |
c906108c | 28143 | |
b90a069a | 28144 | @item T @var{thread-id} |
b8ff78ce | 28145 | @cindex @samp{T} packet |
b90a069a | 28146 | Find out if the thread @var{thread-id} is alive. @xref{thread-id syntax}. |
c906108c | 28147 | |
ee2d5c50 AC |
28148 | Reply: |
28149 | @table @samp | |
28150 | @item OK | |
28151 | thread is still alive | |
b8ff78ce | 28152 | @item E @var{NN} |
ee2d5c50 AC |
28153 | thread is dead |
28154 | @end table | |
28155 | ||
b8ff78ce JB |
28156 | @item v |
28157 | Packets starting with @samp{v} are identified by a multi-letter name, | |
28158 | up to the first @samp{;} or @samp{?} (or the end of the packet). | |
86d30acc | 28159 | |
2d717e4f DJ |
28160 | @item vAttach;@var{pid} |
28161 | @cindex @samp{vAttach} packet | |
8b23ecc4 SL |
28162 | Attach to a new process with the specified process ID @var{pid}. |
28163 | The process ID is a | |
28164 | hexadecimal integer identifying the process. In all-stop mode, all | |
28165 | threads in the attached process are stopped; in non-stop mode, it may be | |
28166 | attached without being stopped if that is supported by the target. | |
28167 | ||
28168 | @c In non-stop mode, on a successful vAttach, the stub should set the | |
28169 | @c current thread to a thread of the newly-attached process. After | |
28170 | @c attaching, GDB queries for the attached process's thread ID with qC. | |
28171 | @c Also note that, from a user perspective, whether or not the | |
28172 | @c target is stopped on attach in non-stop mode depends on whether you | |
28173 | @c use the foreground or background version of the attach command, not | |
28174 | @c on what vAttach does; GDB does the right thing with respect to either | |
28175 | @c stopping or restarting threads. | |
2d717e4f DJ |
28176 | |
28177 | This packet is only available in extended mode (@pxref{extended mode}). | |
28178 | ||
28179 | Reply: | |
28180 | @table @samp | |
28181 | @item E @var{nn} | |
28182 | for an error | |
28183 | @item @r{Any stop packet} | |
8b23ecc4 SL |
28184 | for success in all-stop mode (@pxref{Stop Reply Packets}) |
28185 | @item OK | |
28186 | for success in non-stop mode (@pxref{Remote Non-Stop}) | |
2d717e4f DJ |
28187 | @end table |
28188 | ||
b90a069a | 28189 | @item vCont@r{[};@var{action}@r{[}:@var{thread-id}@r{]]}@dots{} |
b8ff78ce JB |
28190 | @cindex @samp{vCont} packet |
28191 | Resume the inferior, specifying different actions for each thread. | |
b90a069a | 28192 | If an action is specified with no @var{thread-id}, then it is applied to any |
86d30acc | 28193 | threads that don't have a specific action specified; if no default action is |
8b23ecc4 SL |
28194 | specified then other threads should remain stopped in all-stop mode and |
28195 | in their current state in non-stop mode. | |
28196 | Specifying multiple | |
86d30acc | 28197 | default actions is an error; specifying no actions is also an error. |
b90a069a SL |
28198 | Thread IDs are specified using the syntax described in @ref{thread-id syntax}. |
28199 | ||
28200 | Currently supported actions are: | |
86d30acc | 28201 | |
b8ff78ce | 28202 | @table @samp |
86d30acc DJ |
28203 | @item c |
28204 | Continue. | |
b8ff78ce | 28205 | @item C @var{sig} |
8b23ecc4 | 28206 | Continue with signal @var{sig}. The signal @var{sig} should be two hex digits. |
86d30acc DJ |
28207 | @item s |
28208 | Step. | |
b8ff78ce | 28209 | @item S @var{sig} |
8b23ecc4 SL |
28210 | Step with signal @var{sig}. The signal @var{sig} should be two hex digits. |
28211 | @item t | |
28212 | Stop. | |
28213 | @item T @var{sig} | |
28214 | Stop with signal @var{sig}. The signal @var{sig} should be two hex digits. | |
86d30acc DJ |
28215 | @end table |
28216 | ||
8b23ecc4 SL |
28217 | The optional argument @var{addr} normally associated with the |
28218 | @samp{c}, @samp{C}, @samp{s}, and @samp{S} packets is | |
b8ff78ce | 28219 | not supported in @samp{vCont}. |
86d30acc | 28220 | |
8b23ecc4 SL |
28221 | The @samp{t} and @samp{T} actions are only relevant in non-stop mode |
28222 | (@pxref{Remote Non-Stop}) and may be ignored by the stub otherwise. | |
28223 | A stop reply should be generated for any affected thread not already stopped. | |
28224 | When a thread is stopped by means of a @samp{t} action, | |
28225 | the corresponding stop reply should indicate that the thread has stopped with | |
28226 | signal @samp{0}, regardless of whether the target uses some other signal | |
28227 | as an implementation detail. | |
28228 | ||
86d30acc DJ |
28229 | Reply: |
28230 | @xref{Stop Reply Packets}, for the reply specifications. | |
28231 | ||
b8ff78ce JB |
28232 | @item vCont? |
28233 | @cindex @samp{vCont?} packet | |
d3e8051b | 28234 | Request a list of actions supported by the @samp{vCont} packet. |
86d30acc DJ |
28235 | |
28236 | Reply: | |
28237 | @table @samp | |
b8ff78ce JB |
28238 | @item vCont@r{[};@var{action}@dots{}@r{]} |
28239 | The @samp{vCont} packet is supported. Each @var{action} is a supported | |
28240 | command in the @samp{vCont} packet. | |
86d30acc | 28241 | @item |
b8ff78ce | 28242 | The @samp{vCont} packet is not supported. |
86d30acc | 28243 | @end table |
ee2d5c50 | 28244 | |
a6b151f1 DJ |
28245 | @item vFile:@var{operation}:@var{parameter}@dots{} |
28246 | @cindex @samp{vFile} packet | |
28247 | Perform a file operation on the target system. For details, | |
28248 | see @ref{Host I/O Packets}. | |
28249 | ||
68437a39 DJ |
28250 | @item vFlashErase:@var{addr},@var{length} |
28251 | @cindex @samp{vFlashErase} packet | |
28252 | Direct the stub to erase @var{length} bytes of flash starting at | |
28253 | @var{addr}. The region may enclose any number of flash blocks, but | |
28254 | its start and end must fall on block boundaries, as indicated by the | |
79a6e687 BW |
28255 | flash block size appearing in the memory map (@pxref{Memory Map |
28256 | Format}). @value{GDBN} groups flash memory programming operations | |
68437a39 DJ |
28257 | together, and sends a @samp{vFlashDone} request after each group; the |
28258 | stub is allowed to delay erase operation until the @samp{vFlashDone} | |
28259 | packet is received. | |
28260 | ||
b90a069a SL |
28261 | The stub must support @samp{vCont} if it reports support for |
28262 | multiprocess extensions (@pxref{multiprocess extensions}). Note that in | |
28263 | this case @samp{vCont} actions can be specified to apply to all threads | |
28264 | in a process by using the @samp{p@var{pid}.-1} form of the | |
28265 | @var{thread-id}. | |
28266 | ||
68437a39 DJ |
28267 | Reply: |
28268 | @table @samp | |
28269 | @item OK | |
28270 | for success | |
28271 | @item E @var{NN} | |
28272 | for an error | |
28273 | @end table | |
28274 | ||
28275 | @item vFlashWrite:@var{addr}:@var{XX@dots{}} | |
28276 | @cindex @samp{vFlashWrite} packet | |
28277 | Direct the stub to write data to flash address @var{addr}. The data | |
28278 | is passed in binary form using the same encoding as for the @samp{X} | |
28279 | packet (@pxref{Binary Data}). The memory ranges specified by | |
28280 | @samp{vFlashWrite} packets preceding a @samp{vFlashDone} packet must | |
28281 | not overlap, and must appear in order of increasing addresses | |
28282 | (although @samp{vFlashErase} packets for higher addresses may already | |
28283 | have been received; the ordering is guaranteed only between | |
28284 | @samp{vFlashWrite} packets). If a packet writes to an address that was | |
28285 | neither erased by a preceding @samp{vFlashErase} packet nor by some other | |
28286 | target-specific method, the results are unpredictable. | |
28287 | ||
28288 | ||
28289 | Reply: | |
28290 | @table @samp | |
28291 | @item OK | |
28292 | for success | |
28293 | @item E.memtype | |
28294 | for vFlashWrite addressing non-flash memory | |
28295 | @item E @var{NN} | |
28296 | for an error | |
28297 | @end table | |
28298 | ||
28299 | @item vFlashDone | |
28300 | @cindex @samp{vFlashDone} packet | |
28301 | Indicate to the stub that flash programming operation is finished. | |
28302 | The stub is permitted to delay or batch the effects of a group of | |
28303 | @samp{vFlashErase} and @samp{vFlashWrite} packets until a | |
28304 | @samp{vFlashDone} packet is received. The contents of the affected | |
28305 | regions of flash memory are unpredictable until the @samp{vFlashDone} | |
28306 | request is completed. | |
28307 | ||
b90a069a SL |
28308 | @item vKill;@var{pid} |
28309 | @cindex @samp{vKill} packet | |
28310 | Kill the process with the specified process ID. @var{pid} is a | |
28311 | hexadecimal integer identifying the process. This packet is used in | |
28312 | preference to @samp{k} when multiprocess protocol extensions are | |
28313 | supported; see @ref{multiprocess extensions}. | |
28314 | ||
28315 | Reply: | |
28316 | @table @samp | |
28317 | @item E @var{nn} | |
28318 | for an error | |
28319 | @item OK | |
28320 | for success | |
28321 | @end table | |
28322 | ||
2d717e4f DJ |
28323 | @item vRun;@var{filename}@r{[};@var{argument}@r{]}@dots{} |
28324 | @cindex @samp{vRun} packet | |
28325 | Run the program @var{filename}, passing it each @var{argument} on its | |
28326 | command line. The file and arguments are hex-encoded strings. If | |
28327 | @var{filename} is an empty string, the stub may use a default program | |
28328 | (e.g.@: the last program run). The program is created in the stopped | |
9b562ab8 | 28329 | state. |
2d717e4f | 28330 | |
8b23ecc4 SL |
28331 | @c FIXME: What about non-stop mode? |
28332 | ||
2d717e4f DJ |
28333 | This packet is only available in extended mode (@pxref{extended mode}). |
28334 | ||
28335 | Reply: | |
28336 | @table @samp | |
28337 | @item E @var{nn} | |
28338 | for an error | |
28339 | @item @r{Any stop packet} | |
28340 | for success (@pxref{Stop Reply Packets}) | |
28341 | @end table | |
28342 | ||
8b23ecc4 SL |
28343 | @item vStopped |
28344 | @anchor{vStopped packet} | |
28345 | @cindex @samp{vStopped} packet | |
28346 | ||
28347 | In non-stop mode (@pxref{Remote Non-Stop}), acknowledge a previous stop | |
28348 | reply and prompt for the stub to report another one. | |
28349 | ||
28350 | Reply: | |
28351 | @table @samp | |
28352 | @item @r{Any stop packet} | |
28353 | if there is another unreported stop event (@pxref{Stop Reply Packets}) | |
28354 | @item OK | |
28355 | if there are no unreported stop events | |
28356 | @end table | |
28357 | ||
b8ff78ce | 28358 | @item X @var{addr},@var{length}:@var{XX@dots{}} |
9a6253be | 28359 | @anchor{X packet} |
b8ff78ce JB |
28360 | @cindex @samp{X} packet |
28361 | Write data to memory, where the data is transmitted in binary. | |
28362 | @var{addr} is address, @var{length} is number of bytes, | |
0876f84a | 28363 | @samp{@var{XX}@dots{}} is binary data (@pxref{Binary Data}). |
c906108c | 28364 | |
ee2d5c50 AC |
28365 | Reply: |
28366 | @table @samp | |
28367 | @item OK | |
28368 | for success | |
b8ff78ce | 28369 | @item E @var{NN} |
ee2d5c50 AC |
28370 | for an error |
28371 | @end table | |
28372 | ||
b8ff78ce JB |
28373 | @item z @var{type},@var{addr},@var{length} |
28374 | @itemx Z @var{type},@var{addr},@var{length} | |
2f870471 | 28375 | @anchor{insert breakpoint or watchpoint packet} |
b8ff78ce JB |
28376 | @cindex @samp{z} packet |
28377 | @cindex @samp{Z} packets | |
28378 | Insert (@samp{Z}) or remove (@samp{z}) a @var{type} breakpoint or | |
2f870471 AC |
28379 | watchpoint starting at address @var{address} and covering the next |
28380 | @var{length} bytes. | |
ee2d5c50 | 28381 | |
2f870471 AC |
28382 | Each breakpoint and watchpoint packet @var{type} is documented |
28383 | separately. | |
28384 | ||
512217c7 AC |
28385 | @emph{Implementation notes: A remote target shall return an empty string |
28386 | for an unrecognized breakpoint or watchpoint packet @var{type}. A | |
28387 | remote target shall support either both or neither of a given | |
b8ff78ce | 28388 | @samp{Z@var{type}@dots{}} and @samp{z@var{type}@dots{}} packet pair. To |
2f870471 AC |
28389 | avoid potential problems with duplicate packets, the operations should |
28390 | be implemented in an idempotent way.} | |
28391 | ||
b8ff78ce JB |
28392 | @item z0,@var{addr},@var{length} |
28393 | @itemx Z0,@var{addr},@var{length} | |
28394 | @cindex @samp{z0} packet | |
28395 | @cindex @samp{Z0} packet | |
28396 | Insert (@samp{Z0}) or remove (@samp{z0}) a memory breakpoint at address | |
28397 | @var{addr} of size @var{length}. | |
2f870471 AC |
28398 | |
28399 | A memory breakpoint is implemented by replacing the instruction at | |
28400 | @var{addr} with a software breakpoint or trap instruction. The | |
b8ff78ce | 28401 | @var{length} is used by targets that indicates the size of the |
2f870471 AC |
28402 | breakpoint (in bytes) that should be inserted (e.g., the @sc{arm} and |
28403 | @sc{mips} can insert either a 2 or 4 byte breakpoint). | |
c906108c | 28404 | |
2f870471 AC |
28405 | @emph{Implementation note: It is possible for a target to copy or move |
28406 | code that contains memory breakpoints (e.g., when implementing | |
28407 | overlays). The behavior of this packet, in the presence of such a | |
28408 | target, is not defined.} | |
c906108c | 28409 | |
ee2d5c50 AC |
28410 | Reply: |
28411 | @table @samp | |
2f870471 AC |
28412 | @item OK |
28413 | success | |
28414 | @item | |
28415 | not supported | |
b8ff78ce | 28416 | @item E @var{NN} |
ee2d5c50 | 28417 | for an error |
2f870471 AC |
28418 | @end table |
28419 | ||
b8ff78ce JB |
28420 | @item z1,@var{addr},@var{length} |
28421 | @itemx Z1,@var{addr},@var{length} | |
28422 | @cindex @samp{z1} packet | |
28423 | @cindex @samp{Z1} packet | |
28424 | Insert (@samp{Z1}) or remove (@samp{z1}) a hardware breakpoint at | |
28425 | address @var{addr} of size @var{length}. | |
2f870471 AC |
28426 | |
28427 | A hardware breakpoint is implemented using a mechanism that is not | |
28428 | dependant on being able to modify the target's memory. | |
28429 | ||
28430 | @emph{Implementation note: A hardware breakpoint is not affected by code | |
28431 | movement.} | |
28432 | ||
28433 | Reply: | |
28434 | @table @samp | |
ee2d5c50 | 28435 | @item OK |
2f870471 AC |
28436 | success |
28437 | @item | |
28438 | not supported | |
b8ff78ce | 28439 | @item E @var{NN} |
2f870471 AC |
28440 | for an error |
28441 | @end table | |
28442 | ||
b8ff78ce JB |
28443 | @item z2,@var{addr},@var{length} |
28444 | @itemx Z2,@var{addr},@var{length} | |
28445 | @cindex @samp{z2} packet | |
28446 | @cindex @samp{Z2} packet | |
28447 | Insert (@samp{Z2}) or remove (@samp{z2}) a write watchpoint. | |
2f870471 AC |
28448 | |
28449 | Reply: | |
28450 | @table @samp | |
28451 | @item OK | |
28452 | success | |
28453 | @item | |
28454 | not supported | |
b8ff78ce | 28455 | @item E @var{NN} |
2f870471 AC |
28456 | for an error |
28457 | @end table | |
28458 | ||
b8ff78ce JB |
28459 | @item z3,@var{addr},@var{length} |
28460 | @itemx Z3,@var{addr},@var{length} | |
28461 | @cindex @samp{z3} packet | |
28462 | @cindex @samp{Z3} packet | |
28463 | Insert (@samp{Z3}) or remove (@samp{z3}) a read watchpoint. | |
2f870471 AC |
28464 | |
28465 | Reply: | |
28466 | @table @samp | |
28467 | @item OK | |
28468 | success | |
28469 | @item | |
28470 | not supported | |
b8ff78ce | 28471 | @item E @var{NN} |
2f870471 AC |
28472 | for an error |
28473 | @end table | |
28474 | ||
b8ff78ce JB |
28475 | @item z4,@var{addr},@var{length} |
28476 | @itemx Z4,@var{addr},@var{length} | |
28477 | @cindex @samp{z4} packet | |
28478 | @cindex @samp{Z4} packet | |
28479 | Insert (@samp{Z4}) or remove (@samp{z4}) an access watchpoint. | |
2f870471 AC |
28480 | |
28481 | Reply: | |
28482 | @table @samp | |
28483 | @item OK | |
28484 | success | |
28485 | @item | |
28486 | not supported | |
b8ff78ce | 28487 | @item E @var{NN} |
2f870471 | 28488 | for an error |
ee2d5c50 AC |
28489 | @end table |
28490 | ||
28491 | @end table | |
c906108c | 28492 | |
ee2d5c50 AC |
28493 | @node Stop Reply Packets |
28494 | @section Stop Reply Packets | |
28495 | @cindex stop reply packets | |
c906108c | 28496 | |
8b23ecc4 SL |
28497 | The @samp{C}, @samp{c}, @samp{S}, @samp{s}, @samp{vCont}, |
28498 | @samp{vAttach}, @samp{vRun}, @samp{vStopped}, and @samp{?} packets can | |
28499 | receive any of the below as a reply. Except for @samp{?} | |
28500 | and @samp{vStopped}, that reply is only returned | |
b8ff78ce | 28501 | when the target halts. In the below the exact meaning of @dfn{signal |
89be2091 DJ |
28502 | number} is defined by the header @file{include/gdb/signals.h} in the |
28503 | @value{GDBN} source code. | |
c906108c | 28504 | |
b8ff78ce JB |
28505 | As in the description of request packets, we include spaces in the |
28506 | reply templates for clarity; these are not part of the reply packet's | |
28507 | syntax. No @value{GDBN} stop reply packet uses spaces to separate its | |
28508 | components. | |
c906108c | 28509 | |
b8ff78ce | 28510 | @table @samp |
ee2d5c50 | 28511 | |
b8ff78ce | 28512 | @item S @var{AA} |
599b237a | 28513 | The program received signal number @var{AA} (a two-digit hexadecimal |
940178d3 JB |
28514 | number). This is equivalent to a @samp{T} response with no |
28515 | @var{n}:@var{r} pairs. | |
c906108c | 28516 | |
b8ff78ce JB |
28517 | @item T @var{AA} @var{n1}:@var{r1};@var{n2}:@var{r2};@dots{} |
28518 | @cindex @samp{T} packet reply | |
599b237a | 28519 | The program received signal number @var{AA} (a two-digit hexadecimal |
940178d3 JB |
28520 | number). This is equivalent to an @samp{S} response, except that the |
28521 | @samp{@var{n}:@var{r}} pairs can carry values of important registers | |
28522 | and other information directly in the stop reply packet, reducing | |
28523 | round-trip latency. Single-step and breakpoint traps are reported | |
28524 | this way. Each @samp{@var{n}:@var{r}} pair is interpreted as follows: | |
cfa9d6d9 DJ |
28525 | |
28526 | @itemize @bullet | |
b8ff78ce | 28527 | @item |
599b237a | 28528 | If @var{n} is a hexadecimal number, it is a register number, and the |
b8ff78ce JB |
28529 | corresponding @var{r} gives that register's value. @var{r} is a |
28530 | series of bytes in target byte order, with each byte given by a | |
28531 | two-digit hex number. | |
cfa9d6d9 | 28532 | |
b8ff78ce | 28533 | @item |
b90a069a SL |
28534 | If @var{n} is @samp{thread}, then @var{r} is the @var{thread-id} of |
28535 | the stopped thread, as specified in @ref{thread-id syntax}. | |
cfa9d6d9 | 28536 | |
b8ff78ce | 28537 | @item |
cfa9d6d9 DJ |
28538 | If @var{n} is a recognized @dfn{stop reason}, it describes a more |
28539 | specific event that stopped the target. The currently defined stop | |
28540 | reasons are listed below. @var{aa} should be @samp{05}, the trap | |
28541 | signal. At most one stop reason should be present. | |
28542 | ||
b8ff78ce JB |
28543 | @item |
28544 | Otherwise, @value{GDBN} should ignore this @samp{@var{n}:@var{r}} pair | |
28545 | and go on to the next; this allows us to extend the protocol in the | |
28546 | future. | |
cfa9d6d9 DJ |
28547 | @end itemize |
28548 | ||
28549 | The currently defined stop reasons are: | |
28550 | ||
28551 | @table @samp | |
28552 | @item watch | |
28553 | @itemx rwatch | |
28554 | @itemx awatch | |
28555 | The packet indicates a watchpoint hit, and @var{r} is the data address, in | |
28556 | hex. | |
28557 | ||
28558 | @cindex shared library events, remote reply | |
28559 | @item library | |
28560 | The packet indicates that the loaded libraries have changed. | |
28561 | @value{GDBN} should use @samp{qXfer:libraries:read} to fetch a new | |
28562 | list of loaded libraries. @var{r} is ignored. | |
bacec72f MS |
28563 | |
28564 | @cindex replay log events, remote reply | |
28565 | @item replaylog | |
28566 | The packet indicates that the target cannot continue replaying | |
28567 | logged execution events, because it has reached the end (or the | |
28568 | beginning when executing backward) of the log. The value of @var{r} | |
28569 | will be either @samp{begin} or @samp{end}. @xref{Reverse Execution}, | |
28570 | for more information. | |
28571 | ||
28572 | ||
cfa9d6d9 | 28573 | @end table |
ee2d5c50 | 28574 | |
b8ff78ce | 28575 | @item W @var{AA} |
b90a069a | 28576 | @itemx W @var{AA} ; process:@var{pid} |
8e04817f | 28577 | The process exited, and @var{AA} is the exit status. This is only |
ee2d5c50 AC |
28578 | applicable to certain targets. |
28579 | ||
b90a069a SL |
28580 | The second form of the response, including the process ID of the exited |
28581 | process, can be used only when @value{GDBN} has reported support for | |
28582 | multiprocess protocol extensions; see @ref{multiprocess extensions}. | |
28583 | The @var{pid} is formatted as a big-endian hex string. | |
28584 | ||
b8ff78ce | 28585 | @item X @var{AA} |
b90a069a | 28586 | @itemx X @var{AA} ; process:@var{pid} |
8e04817f | 28587 | The process terminated with signal @var{AA}. |
c906108c | 28588 | |
b90a069a SL |
28589 | The second form of the response, including the process ID of the |
28590 | terminated process, can be used only when @value{GDBN} has reported | |
28591 | support for multiprocess protocol extensions; see @ref{multiprocess | |
28592 | extensions}. The @var{pid} is formatted as a big-endian hex string. | |
28593 | ||
b8ff78ce JB |
28594 | @item O @var{XX}@dots{} |
28595 | @samp{@var{XX}@dots{}} is hex encoding of @sc{ascii} data, to be | |
28596 | written as the program's console output. This can happen at any time | |
28597 | while the program is running and the debugger should continue to wait | |
8b23ecc4 | 28598 | for @samp{W}, @samp{T}, etc. This reply is not permitted in non-stop mode. |
0ce1b118 | 28599 | |
b8ff78ce | 28600 | @item F @var{call-id},@var{parameter}@dots{} |
0ce1b118 CV |
28601 | @var{call-id} is the identifier which says which host system call should |
28602 | be called. This is just the name of the function. Translation into the | |
28603 | correct system call is only applicable as it's defined in @value{GDBN}. | |
79a6e687 | 28604 | @xref{File-I/O Remote Protocol Extension}, for a list of implemented |
0ce1b118 CV |
28605 | system calls. |
28606 | ||
b8ff78ce JB |
28607 | @samp{@var{parameter}@dots{}} is a list of parameters as defined for |
28608 | this very system call. | |
0ce1b118 | 28609 | |
b8ff78ce JB |
28610 | The target replies with this packet when it expects @value{GDBN} to |
28611 | call a host system call on behalf of the target. @value{GDBN} replies | |
28612 | with an appropriate @samp{F} packet and keeps up waiting for the next | |
28613 | reply packet from the target. The latest @samp{C}, @samp{c}, @samp{S} | |
79a6e687 BW |
28614 | or @samp{s} action is expected to be continued. @xref{File-I/O Remote |
28615 | Protocol Extension}, for more details. | |
0ce1b118 | 28616 | |
ee2d5c50 AC |
28617 | @end table |
28618 | ||
28619 | @node General Query Packets | |
28620 | @section General Query Packets | |
9c16f35a | 28621 | @cindex remote query requests |
c906108c | 28622 | |
5f3bebba JB |
28623 | Packets starting with @samp{q} are @dfn{general query packets}; |
28624 | packets starting with @samp{Q} are @dfn{general set packets}. General | |
28625 | query and set packets are a semi-unified form for retrieving and | |
28626 | sending information to and from the stub. | |
28627 | ||
28628 | The initial letter of a query or set packet is followed by a name | |
28629 | indicating what sort of thing the packet applies to. For example, | |
28630 | @value{GDBN} may use a @samp{qSymbol} packet to exchange symbol | |
28631 | definitions with the stub. These packet names follow some | |
28632 | conventions: | |
28633 | ||
28634 | @itemize @bullet | |
28635 | @item | |
28636 | The name must not contain commas, colons or semicolons. | |
28637 | @item | |
28638 | Most @value{GDBN} query and set packets have a leading upper case | |
28639 | letter. | |
28640 | @item | |
28641 | The names of custom vendor packets should use a company prefix, in | |
28642 | lower case, followed by a period. For example, packets designed at | |
28643 | the Acme Corporation might begin with @samp{qacme.foo} (for querying | |
28644 | foos) or @samp{Qacme.bar} (for setting bars). | |
28645 | @end itemize | |
28646 | ||
aa56d27a JB |
28647 | The name of a query or set packet should be separated from any |
28648 | parameters by a @samp{:}; the parameters themselves should be | |
28649 | separated by @samp{,} or @samp{;}. Stubs must be careful to match the | |
369af7bd DJ |
28650 | full packet name, and check for a separator or the end of the packet, |
28651 | in case two packet names share a common prefix. New packets should not begin | |
28652 | with @samp{qC}, @samp{qP}, or @samp{qL}@footnote{The @samp{qP} and @samp{qL} | |
28653 | packets predate these conventions, and have arguments without any terminator | |
28654 | for the packet name; we suspect they are in widespread use in places that | |
28655 | are difficult to upgrade. The @samp{qC} packet has no arguments, but some | |
28656 | existing stubs (e.g.@: RedBoot) are known to not check for the end of the | |
28657 | packet.}. | |
c906108c | 28658 | |
b8ff78ce JB |
28659 | Like the descriptions of the other packets, each description here |
28660 | has a template showing the packet's overall syntax, followed by an | |
28661 | explanation of the packet's meaning. We include spaces in some of the | |
28662 | templates for clarity; these are not part of the packet's syntax. No | |
28663 | @value{GDBN} packet uses spaces to separate its components. | |
28664 | ||
5f3bebba JB |
28665 | Here are the currently defined query and set packets: |
28666 | ||
b8ff78ce | 28667 | @table @samp |
c906108c | 28668 | |
b8ff78ce | 28669 | @item qC |
9c16f35a | 28670 | @cindex current thread, remote request |
b8ff78ce | 28671 | @cindex @samp{qC} packet |
b90a069a | 28672 | Return the current thread ID. |
ee2d5c50 AC |
28673 | |
28674 | Reply: | |
28675 | @table @samp | |
b90a069a SL |
28676 | @item QC @var{thread-id} |
28677 | Where @var{thread-id} is a thread ID as documented in | |
28678 | @ref{thread-id syntax}. | |
b8ff78ce | 28679 | @item @r{(anything else)} |
b90a069a | 28680 | Any other reply implies the old thread ID. |
ee2d5c50 AC |
28681 | @end table |
28682 | ||
b8ff78ce | 28683 | @item qCRC:@var{addr},@var{length} |
ff2587ec | 28684 | @cindex CRC of memory block, remote request |
b8ff78ce | 28685 | @cindex @samp{qCRC} packet |
99e008fe EZ |
28686 | Compute the CRC checksum of a block of memory using CRC-32 defined in |
28687 | IEEE 802.3. The CRC is computed byte at a time, taking the most | |
28688 | significant bit of each byte first. The initial pattern code | |
28689 | @code{0xffffffff} is used to ensure leading zeros affect the CRC. | |
28690 | ||
28691 | @emph{Note:} This is the same CRC used in validating separate debug | |
28692 | files (@pxref{Separate Debug Files, , Debugging Information in Separate | |
28693 | Files}). However the algorithm is slightly different. When validating | |
28694 | separate debug files, the CRC is computed taking the @emph{least} | |
28695 | significant bit of each byte first, and the final result is inverted to | |
28696 | detect trailing zeros. | |
28697 | ||
ff2587ec WZ |
28698 | Reply: |
28699 | @table @samp | |
b8ff78ce | 28700 | @item E @var{NN} |
ff2587ec | 28701 | An error (such as memory fault) |
b8ff78ce JB |
28702 | @item C @var{crc32} |
28703 | The specified memory region's checksum is @var{crc32}. | |
ff2587ec WZ |
28704 | @end table |
28705 | ||
b8ff78ce JB |
28706 | @item qfThreadInfo |
28707 | @itemx qsThreadInfo | |
9c16f35a | 28708 | @cindex list active threads, remote request |
b8ff78ce JB |
28709 | @cindex @samp{qfThreadInfo} packet |
28710 | @cindex @samp{qsThreadInfo} packet | |
b90a069a | 28711 | Obtain a list of all active thread IDs from the target (OS). Since there |
8e04817f AC |
28712 | may be too many active threads to fit into one reply packet, this query |
28713 | works iteratively: it may require more than one query/reply sequence to | |
28714 | obtain the entire list of threads. The first query of the sequence will | |
b8ff78ce JB |
28715 | be the @samp{qfThreadInfo} query; subsequent queries in the |
28716 | sequence will be the @samp{qsThreadInfo} query. | |
ee2d5c50 | 28717 | |
b8ff78ce | 28718 | NOTE: This packet replaces the @samp{qL} query (see below). |
ee2d5c50 AC |
28719 | |
28720 | Reply: | |
28721 | @table @samp | |
b90a069a SL |
28722 | @item m @var{thread-id} |
28723 | A single thread ID | |
28724 | @item m @var{thread-id},@var{thread-id}@dots{} | |
28725 | a comma-separated list of thread IDs | |
b8ff78ce JB |
28726 | @item l |
28727 | (lower case letter @samp{L}) denotes end of list. | |
ee2d5c50 AC |
28728 | @end table |
28729 | ||
28730 | In response to each query, the target will reply with a list of one or | |
b90a069a | 28731 | more thread IDs, separated by commas. |
e1aac25b | 28732 | @value{GDBN} will respond to each reply with a request for more thread |
b8ff78ce | 28733 | ids (using the @samp{qs} form of the query), until the target responds |
b90a069a SL |
28734 | with @samp{l} (lower-case el, for @dfn{last}). |
28735 | Refer to @ref{thread-id syntax}, for the format of the @var{thread-id} | |
28736 | fields. | |
c906108c | 28737 | |
b8ff78ce | 28738 | @item qGetTLSAddr:@var{thread-id},@var{offset},@var{lm} |
ff2587ec | 28739 | @cindex get thread-local storage address, remote request |
b8ff78ce | 28740 | @cindex @samp{qGetTLSAddr} packet |
ff2587ec WZ |
28741 | Fetch the address associated with thread local storage specified |
28742 | by @var{thread-id}, @var{offset}, and @var{lm}. | |
28743 | ||
b90a069a SL |
28744 | @var{thread-id} is the thread ID associated with the |
28745 | thread for which to fetch the TLS address. @xref{thread-id syntax}. | |
ff2587ec WZ |
28746 | |
28747 | @var{offset} is the (big endian, hex encoded) offset associated with the | |
28748 | thread local variable. (This offset is obtained from the debug | |
28749 | information associated with the variable.) | |
28750 | ||
db2e3e2e | 28751 | @var{lm} is the (big endian, hex encoded) OS/ABI-specific encoding of the |
ff2587ec WZ |
28752 | the load module associated with the thread local storage. For example, |
28753 | a @sc{gnu}/Linux system will pass the link map address of the shared | |
28754 | object associated with the thread local storage under consideration. | |
28755 | Other operating environments may choose to represent the load module | |
28756 | differently, so the precise meaning of this parameter will vary. | |
ee2d5c50 AC |
28757 | |
28758 | Reply: | |
b8ff78ce JB |
28759 | @table @samp |
28760 | @item @var{XX}@dots{} | |
ff2587ec WZ |
28761 | Hex encoded (big endian) bytes representing the address of the thread |
28762 | local storage requested. | |
28763 | ||
b8ff78ce JB |
28764 | @item E @var{nn} |
28765 | An error occurred. @var{nn} are hex digits. | |
ff2587ec | 28766 | |
b8ff78ce JB |
28767 | @item |
28768 | An empty reply indicates that @samp{qGetTLSAddr} is not supported by the stub. | |
ee2d5c50 AC |
28769 | @end table |
28770 | ||
b8ff78ce | 28771 | @item qL @var{startflag} @var{threadcount} @var{nextthread} |
8e04817f AC |
28772 | Obtain thread information from RTOS. Where: @var{startflag} (one hex |
28773 | digit) is one to indicate the first query and zero to indicate a | |
28774 | subsequent query; @var{threadcount} (two hex digits) is the maximum | |
28775 | number of threads the response packet can contain; and @var{nextthread} | |
28776 | (eight hex digits), for subsequent queries (@var{startflag} is zero), is | |
28777 | returned in the response as @var{argthread}. | |
ee2d5c50 | 28778 | |
b8ff78ce | 28779 | Don't use this packet; use the @samp{qfThreadInfo} query instead (see above). |
ee2d5c50 AC |
28780 | |
28781 | Reply: | |
28782 | @table @samp | |
b8ff78ce | 28783 | @item qM @var{count} @var{done} @var{argthread} @var{thread}@dots{} |
8e04817f AC |
28784 | Where: @var{count} (two hex digits) is the number of threads being |
28785 | returned; @var{done} (one hex digit) is zero to indicate more threads | |
28786 | and one indicates no further threads; @var{argthreadid} (eight hex | |
b8ff78ce | 28787 | digits) is @var{nextthread} from the request packet; @var{thread}@dots{} |
ee2d5c50 | 28788 | is a sequence of thread IDs from the target. @var{threadid} (eight hex |
8e04817f | 28789 | digits). See @code{remote.c:parse_threadlist_response()}. |
ee2d5c50 | 28790 | @end table |
c906108c | 28791 | |
b8ff78ce | 28792 | @item qOffsets |
9c16f35a | 28793 | @cindex section offsets, remote request |
b8ff78ce | 28794 | @cindex @samp{qOffsets} packet |
31d99776 DJ |
28795 | Get section offsets that the target used when relocating the downloaded |
28796 | image. | |
c906108c | 28797 | |
ee2d5c50 AC |
28798 | Reply: |
28799 | @table @samp | |
31d99776 DJ |
28800 | @item Text=@var{xxx};Data=@var{yyy}@r{[};Bss=@var{zzz}@r{]} |
28801 | Relocate the @code{Text} section by @var{xxx} from its original address. | |
28802 | Relocate the @code{Data} section by @var{yyy} from its original address. | |
28803 | If the object file format provides segment information (e.g.@: @sc{elf} | |
28804 | @samp{PT_LOAD} program headers), @value{GDBN} will relocate entire | |
28805 | segments by the supplied offsets. | |
28806 | ||
28807 | @emph{Note: while a @code{Bss} offset may be included in the response, | |
28808 | @value{GDBN} ignores this and instead applies the @code{Data} offset | |
28809 | to the @code{Bss} section.} | |
28810 | ||
28811 | @item TextSeg=@var{xxx}@r{[};DataSeg=@var{yyy}@r{]} | |
28812 | Relocate the first segment of the object file, which conventionally | |
28813 | contains program code, to a starting address of @var{xxx}. If | |
28814 | @samp{DataSeg} is specified, relocate the second segment, which | |
28815 | conventionally contains modifiable data, to a starting address of | |
28816 | @var{yyy}. @value{GDBN} will report an error if the object file | |
28817 | does not contain segment information, or does not contain at least | |
28818 | as many segments as mentioned in the reply. Extra segments are | |
28819 | kept at fixed offsets relative to the last relocated segment. | |
ee2d5c50 AC |
28820 | @end table |
28821 | ||
b90a069a | 28822 | @item qP @var{mode} @var{thread-id} |
9c16f35a | 28823 | @cindex thread information, remote request |
b8ff78ce | 28824 | @cindex @samp{qP} packet |
b90a069a SL |
28825 | Returns information on @var{thread-id}. Where: @var{mode} is a hex |
28826 | encoded 32 bit mode; @var{thread-id} is a thread ID | |
28827 | (@pxref{thread-id syntax}). | |
ee2d5c50 | 28828 | |
aa56d27a JB |
28829 | Don't use this packet; use the @samp{qThreadExtraInfo} query instead |
28830 | (see below). | |
28831 | ||
b8ff78ce | 28832 | Reply: see @code{remote.c:remote_unpack_thread_info_response()}. |
c906108c | 28833 | |
8b23ecc4 SL |
28834 | @item QNonStop:1 |
28835 | @item QNonStop:0 | |
28836 | @cindex non-stop mode, remote request | |
28837 | @cindex @samp{QNonStop} packet | |
28838 | @anchor{QNonStop} | |
28839 | Enter non-stop (@samp{QNonStop:1}) or all-stop (@samp{QNonStop:0}) mode. | |
28840 | @xref{Remote Non-Stop}, for more information. | |
28841 | ||
28842 | Reply: | |
28843 | @table @samp | |
28844 | @item OK | |
28845 | The request succeeded. | |
28846 | ||
28847 | @item E @var{nn} | |
28848 | An error occurred. @var{nn} are hex digits. | |
28849 | ||
28850 | @item | |
28851 | An empty reply indicates that @samp{QNonStop} is not supported by | |
28852 | the stub. | |
28853 | @end table | |
28854 | ||
28855 | This packet is not probed by default; the remote stub must request it, | |
28856 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
28857 | Use of this packet is controlled by the @code{set non-stop} command; | |
28858 | @pxref{Non-Stop Mode}. | |
28859 | ||
89be2091 DJ |
28860 | @item QPassSignals: @var{signal} @r{[};@var{signal}@r{]}@dots{} |
28861 | @cindex pass signals to inferior, remote request | |
28862 | @cindex @samp{QPassSignals} packet | |
23181151 | 28863 | @anchor{QPassSignals} |
89be2091 DJ |
28864 | Each listed @var{signal} should be passed directly to the inferior process. |
28865 | Signals are numbered identically to continue packets and stop replies | |
28866 | (@pxref{Stop Reply Packets}). Each @var{signal} list item should be | |
28867 | strictly greater than the previous item. These signals do not need to stop | |
28868 | the inferior, or be reported to @value{GDBN}. All other signals should be | |
28869 | reported to @value{GDBN}. Multiple @samp{QPassSignals} packets do not | |
28870 | combine; any earlier @samp{QPassSignals} list is completely replaced by the | |
28871 | new list. This packet improves performance when using @samp{handle | |
28872 | @var{signal} nostop noprint pass}. | |
28873 | ||
28874 | Reply: | |
28875 | @table @samp | |
28876 | @item OK | |
28877 | The request succeeded. | |
28878 | ||
28879 | @item E @var{nn} | |
28880 | An error occurred. @var{nn} are hex digits. | |
28881 | ||
28882 | @item | |
28883 | An empty reply indicates that @samp{QPassSignals} is not supported by | |
28884 | the stub. | |
28885 | @end table | |
28886 | ||
28887 | Use of this packet is controlled by the @code{set remote pass-signals} | |
79a6e687 | 28888 | command (@pxref{Remote Configuration, set remote pass-signals}). |
89be2091 DJ |
28889 | This packet is not probed by default; the remote stub must request it, |
28890 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
28891 | ||
b8ff78ce | 28892 | @item qRcmd,@var{command} |
ff2587ec | 28893 | @cindex execute remote command, remote request |
b8ff78ce | 28894 | @cindex @samp{qRcmd} packet |
ff2587ec | 28895 | @var{command} (hex encoded) is passed to the local interpreter for |
b8ff78ce JB |
28896 | execution. Invalid commands should be reported using the output |
28897 | string. Before the final result packet, the target may also respond | |
28898 | with a number of intermediate @samp{O@var{output}} console output | |
28899 | packets. @emph{Implementors should note that providing access to a | |
28900 | stubs's interpreter may have security implications}. | |
fa93a9d8 | 28901 | |
ff2587ec WZ |
28902 | Reply: |
28903 | @table @samp | |
28904 | @item OK | |
28905 | A command response with no output. | |
28906 | @item @var{OUTPUT} | |
28907 | A command response with the hex encoded output string @var{OUTPUT}. | |
b8ff78ce | 28908 | @item E @var{NN} |
ff2587ec | 28909 | Indicate a badly formed request. |
b8ff78ce JB |
28910 | @item |
28911 | An empty reply indicates that @samp{qRcmd} is not recognized. | |
ff2587ec | 28912 | @end table |
fa93a9d8 | 28913 | |
aa56d27a JB |
28914 | (Note that the @code{qRcmd} packet's name is separated from the |
28915 | command by a @samp{,}, not a @samp{:}, contrary to the naming | |
28916 | conventions above. Please don't use this packet as a model for new | |
28917 | packets.) | |
28918 | ||
08388c79 DE |
28919 | @item qSearch:memory:@var{address};@var{length};@var{search-pattern} |
28920 | @cindex searching memory, in remote debugging | |
28921 | @cindex @samp{qSearch:memory} packet | |
28922 | @anchor{qSearch memory} | |
28923 | Search @var{length} bytes at @var{address} for @var{search-pattern}. | |
28924 | @var{address} and @var{length} are encoded in hex. | |
28925 | @var{search-pattern} is a sequence of bytes, hex encoded. | |
28926 | ||
28927 | Reply: | |
28928 | @table @samp | |
28929 | @item 0 | |
28930 | The pattern was not found. | |
28931 | @item 1,address | |
28932 | The pattern was found at @var{address}. | |
28933 | @item E @var{NN} | |
28934 | A badly formed request or an error was encountered while searching memory. | |
28935 | @item | |
28936 | An empty reply indicates that @samp{qSearch:memory} is not recognized. | |
28937 | @end table | |
28938 | ||
a6f3e723 SL |
28939 | @item QStartNoAckMode |
28940 | @cindex @samp{QStartNoAckMode} packet | |
28941 | @anchor{QStartNoAckMode} | |
28942 | Request that the remote stub disable the normal @samp{+}/@samp{-} | |
28943 | protocol acknowledgments (@pxref{Packet Acknowledgment}). | |
28944 | ||
28945 | Reply: | |
28946 | @table @samp | |
28947 | @item OK | |
28948 | The stub has switched to no-acknowledgment mode. | |
28949 | @value{GDBN} acknowledges this reponse, | |
28950 | but neither the stub nor @value{GDBN} shall send or expect further | |
28951 | @samp{+}/@samp{-} acknowledgments in the current connection. | |
28952 | @item | |
28953 | An empty reply indicates that the stub does not support no-acknowledgment mode. | |
28954 | @end table | |
28955 | ||
be2a5f71 DJ |
28956 | @item qSupported @r{[}:@var{gdbfeature} @r{[};@var{gdbfeature}@r{]}@dots{} @r{]} |
28957 | @cindex supported packets, remote query | |
28958 | @cindex features of the remote protocol | |
28959 | @cindex @samp{qSupported} packet | |
0876f84a | 28960 | @anchor{qSupported} |
be2a5f71 DJ |
28961 | Tell the remote stub about features supported by @value{GDBN}, and |
28962 | query the stub for features it supports. This packet allows | |
28963 | @value{GDBN} and the remote stub to take advantage of each others' | |
28964 | features. @samp{qSupported} also consolidates multiple feature probes | |
28965 | at startup, to improve @value{GDBN} performance---a single larger | |
28966 | packet performs better than multiple smaller probe packets on | |
28967 | high-latency links. Some features may enable behavior which must not | |
28968 | be on by default, e.g.@: because it would confuse older clients or | |
28969 | stubs. Other features may describe packets which could be | |
28970 | automatically probed for, but are not. These features must be | |
28971 | reported before @value{GDBN} will use them. This ``default | |
28972 | unsupported'' behavior is not appropriate for all packets, but it | |
28973 | helps to keep the initial connection time under control with new | |
28974 | versions of @value{GDBN} which support increasing numbers of packets. | |
28975 | ||
28976 | Reply: | |
28977 | @table @samp | |
28978 | @item @var{stubfeature} @r{[};@var{stubfeature}@r{]}@dots{} | |
28979 | The stub supports or does not support each returned @var{stubfeature}, | |
28980 | depending on the form of each @var{stubfeature} (see below for the | |
28981 | possible forms). | |
28982 | @item | |
28983 | An empty reply indicates that @samp{qSupported} is not recognized, | |
28984 | or that no features needed to be reported to @value{GDBN}. | |
28985 | @end table | |
28986 | ||
28987 | The allowed forms for each feature (either a @var{gdbfeature} in the | |
28988 | @samp{qSupported} packet, or a @var{stubfeature} in the response) | |
28989 | are: | |
28990 | ||
28991 | @table @samp | |
28992 | @item @var{name}=@var{value} | |
28993 | The remote protocol feature @var{name} is supported, and associated | |
28994 | with the specified @var{value}. The format of @var{value} depends | |
28995 | on the feature, but it must not include a semicolon. | |
28996 | @item @var{name}+ | |
28997 | The remote protocol feature @var{name} is supported, and does not | |
28998 | need an associated value. | |
28999 | @item @var{name}- | |
29000 | The remote protocol feature @var{name} is not supported. | |
29001 | @item @var{name}? | |
29002 | The remote protocol feature @var{name} may be supported, and | |
29003 | @value{GDBN} should auto-detect support in some other way when it is | |
29004 | needed. This form will not be used for @var{gdbfeature} notifications, | |
29005 | but may be used for @var{stubfeature} responses. | |
29006 | @end table | |
29007 | ||
29008 | Whenever the stub receives a @samp{qSupported} request, the | |
29009 | supplied set of @value{GDBN} features should override any previous | |
29010 | request. This allows @value{GDBN} to put the stub in a known | |
29011 | state, even if the stub had previously been communicating with | |
29012 | a different version of @value{GDBN}. | |
29013 | ||
b90a069a SL |
29014 | The following values of @var{gdbfeature} (for the packet sent by @value{GDBN}) |
29015 | are defined: | |
29016 | ||
29017 | @table @samp | |
29018 | @item multiprocess | |
29019 | This feature indicates whether @value{GDBN} supports multiprocess | |
29020 | extensions to the remote protocol. @value{GDBN} does not use such | |
29021 | extensions unless the stub also reports that it supports them by | |
29022 | including @samp{multiprocess+} in its @samp{qSupported} reply. | |
29023 | @xref{multiprocess extensions}, for details. | |
29024 | @end table | |
29025 | ||
29026 | Stubs should ignore any unknown values for | |
be2a5f71 DJ |
29027 | @var{gdbfeature}. Any @value{GDBN} which sends a @samp{qSupported} |
29028 | packet supports receiving packets of unlimited length (earlier | |
b90a069a | 29029 | versions of @value{GDBN} may reject overly long responses). Additional values |
be2a5f71 DJ |
29030 | for @var{gdbfeature} may be defined in the future to let the stub take |
29031 | advantage of new features in @value{GDBN}, e.g.@: incompatible | |
b90a069a SL |
29032 | improvements in the remote protocol---the @samp{multiprocess} feature is |
29033 | an example of such a feature. The stub's reply should be independent | |
be2a5f71 DJ |
29034 | of the @var{gdbfeature} entries sent by @value{GDBN}; first @value{GDBN} |
29035 | describes all the features it supports, and then the stub replies with | |
29036 | all the features it supports. | |
29037 | ||
29038 | Similarly, @value{GDBN} will silently ignore unrecognized stub feature | |
29039 | responses, as long as each response uses one of the standard forms. | |
29040 | ||
29041 | Some features are flags. A stub which supports a flag feature | |
29042 | should respond with a @samp{+} form response. Other features | |
29043 | require values, and the stub should respond with an @samp{=} | |
29044 | form response. | |
29045 | ||
29046 | Each feature has a default value, which @value{GDBN} will use if | |
29047 | @samp{qSupported} is not available or if the feature is not mentioned | |
29048 | in the @samp{qSupported} response. The default values are fixed; a | |
29049 | stub is free to omit any feature responses that match the defaults. | |
29050 | ||
29051 | Not all features can be probed, but for those which can, the probing | |
29052 | mechanism is useful: in some cases, a stub's internal | |
29053 | architecture may not allow the protocol layer to know some information | |
29054 | about the underlying target in advance. This is especially common in | |
29055 | stubs which may be configured for multiple targets. | |
29056 | ||
29057 | These are the currently defined stub features and their properties: | |
29058 | ||
cfa9d6d9 | 29059 | @multitable @columnfractions 0.35 0.2 0.12 0.2 |
be2a5f71 DJ |
29060 | @c NOTE: The first row should be @headitem, but we do not yet require |
29061 | @c a new enough version of Texinfo (4.7) to use @headitem. | |
0876f84a | 29062 | @item Feature Name |
be2a5f71 DJ |
29063 | @tab Value Required |
29064 | @tab Default | |
29065 | @tab Probe Allowed | |
29066 | ||
29067 | @item @samp{PacketSize} | |
29068 | @tab Yes | |
29069 | @tab @samp{-} | |
29070 | @tab No | |
29071 | ||
0876f84a DJ |
29072 | @item @samp{qXfer:auxv:read} |
29073 | @tab No | |
29074 | @tab @samp{-} | |
29075 | @tab Yes | |
29076 | ||
23181151 DJ |
29077 | @item @samp{qXfer:features:read} |
29078 | @tab No | |
29079 | @tab @samp{-} | |
29080 | @tab Yes | |
29081 | ||
cfa9d6d9 DJ |
29082 | @item @samp{qXfer:libraries:read} |
29083 | @tab No | |
29084 | @tab @samp{-} | |
29085 | @tab Yes | |
29086 | ||
68437a39 DJ |
29087 | @item @samp{qXfer:memory-map:read} |
29088 | @tab No | |
29089 | @tab @samp{-} | |
29090 | @tab Yes | |
29091 | ||
0e7f50da UW |
29092 | @item @samp{qXfer:spu:read} |
29093 | @tab No | |
29094 | @tab @samp{-} | |
29095 | @tab Yes | |
29096 | ||
29097 | @item @samp{qXfer:spu:write} | |
29098 | @tab No | |
29099 | @tab @samp{-} | |
29100 | @tab Yes | |
29101 | ||
4aa995e1 PA |
29102 | @item @samp{qXfer:siginfo:read} |
29103 | @tab No | |
29104 | @tab @samp{-} | |
29105 | @tab Yes | |
29106 | ||
29107 | @item @samp{qXfer:siginfo:write} | |
29108 | @tab No | |
29109 | @tab @samp{-} | |
29110 | @tab Yes | |
29111 | ||
8b23ecc4 SL |
29112 | @item @samp{QNonStop} |
29113 | @tab No | |
29114 | @tab @samp{-} | |
29115 | @tab Yes | |
29116 | ||
89be2091 DJ |
29117 | @item @samp{QPassSignals} |
29118 | @tab No | |
29119 | @tab @samp{-} | |
29120 | @tab Yes | |
29121 | ||
a6f3e723 SL |
29122 | @item @samp{QStartNoAckMode} |
29123 | @tab No | |
29124 | @tab @samp{-} | |
29125 | @tab Yes | |
29126 | ||
b90a069a SL |
29127 | @item @samp{multiprocess} |
29128 | @tab No | |
29129 | @tab @samp{-} | |
29130 | @tab No | |
29131 | ||
782b2b07 SS |
29132 | @item @samp{ConditionalTracepoints} |
29133 | @tab No | |
29134 | @tab @samp{-} | |
29135 | @tab No | |
29136 | ||
0d772ac9 MS |
29137 | @item @samp{ReverseContinue} |
29138 | @tab No | |
29139 | @tab @samp{+} | |
29140 | @tab No | |
29141 | ||
29142 | @item @samp{ReverseStep} | |
29143 | @tab No | |
29144 | @tab @samp{+} | |
29145 | @tab No | |
29146 | ||
be2a5f71 DJ |
29147 | @end multitable |
29148 | ||
29149 | These are the currently defined stub features, in more detail: | |
29150 | ||
29151 | @table @samp | |
29152 | @cindex packet size, remote protocol | |
29153 | @item PacketSize=@var{bytes} | |
29154 | The remote stub can accept packets up to at least @var{bytes} in | |
29155 | length. @value{GDBN} will send packets up to this size for bulk | |
29156 | transfers, and will never send larger packets. This is a limit on the | |
29157 | data characters in the packet, including the frame and checksum. | |
29158 | There is no trailing NUL byte in a remote protocol packet; if the stub | |
29159 | stores packets in a NUL-terminated format, it should allow an extra | |
29160 | byte in its buffer for the NUL. If this stub feature is not supported, | |
29161 | @value{GDBN} guesses based on the size of the @samp{g} packet response. | |
29162 | ||
0876f84a DJ |
29163 | @item qXfer:auxv:read |
29164 | The remote stub understands the @samp{qXfer:auxv:read} packet | |
29165 | (@pxref{qXfer auxiliary vector read}). | |
29166 | ||
23181151 DJ |
29167 | @item qXfer:features:read |
29168 | The remote stub understands the @samp{qXfer:features:read} packet | |
29169 | (@pxref{qXfer target description read}). | |
29170 | ||
cfa9d6d9 DJ |
29171 | @item qXfer:libraries:read |
29172 | The remote stub understands the @samp{qXfer:libraries:read} packet | |
29173 | (@pxref{qXfer library list read}). | |
29174 | ||
23181151 DJ |
29175 | @item qXfer:memory-map:read |
29176 | The remote stub understands the @samp{qXfer:memory-map:read} packet | |
29177 | (@pxref{qXfer memory map read}). | |
29178 | ||
0e7f50da UW |
29179 | @item qXfer:spu:read |
29180 | The remote stub understands the @samp{qXfer:spu:read} packet | |
29181 | (@pxref{qXfer spu read}). | |
29182 | ||
29183 | @item qXfer:spu:write | |
29184 | The remote stub understands the @samp{qXfer:spu:write} packet | |
29185 | (@pxref{qXfer spu write}). | |
29186 | ||
4aa995e1 PA |
29187 | @item qXfer:siginfo:read |
29188 | The remote stub understands the @samp{qXfer:siginfo:read} packet | |
29189 | (@pxref{qXfer siginfo read}). | |
29190 | ||
29191 | @item qXfer:siginfo:write | |
29192 | The remote stub understands the @samp{qXfer:siginfo:write} packet | |
29193 | (@pxref{qXfer siginfo write}). | |
29194 | ||
8b23ecc4 SL |
29195 | @item QNonStop |
29196 | The remote stub understands the @samp{QNonStop} packet | |
29197 | (@pxref{QNonStop}). | |
29198 | ||
23181151 DJ |
29199 | @item QPassSignals |
29200 | The remote stub understands the @samp{QPassSignals} packet | |
29201 | (@pxref{QPassSignals}). | |
29202 | ||
a6f3e723 SL |
29203 | @item QStartNoAckMode |
29204 | The remote stub understands the @samp{QStartNoAckMode} packet and | |
29205 | prefers to operate in no-acknowledgment mode. @xref{Packet Acknowledgment}. | |
29206 | ||
b90a069a SL |
29207 | @item multiprocess |
29208 | @anchor{multiprocess extensions} | |
29209 | @cindex multiprocess extensions, in remote protocol | |
29210 | The remote stub understands the multiprocess extensions to the remote | |
29211 | protocol syntax. The multiprocess extensions affect the syntax of | |
29212 | thread IDs in both packets and replies (@pxref{thread-id syntax}), and | |
29213 | add process IDs to the @samp{D} packet and @samp{W} and @samp{X} | |
29214 | replies. Note that reporting this feature indicates support for the | |
29215 | syntactic extensions only, not that the stub necessarily supports | |
29216 | debugging of more than one process at a time. The stub must not use | |
29217 | multiprocess extensions in packet replies unless @value{GDBN} has also | |
29218 | indicated it supports them in its @samp{qSupported} request. | |
29219 | ||
07e059b5 VP |
29220 | @item qXfer:osdata:read |
29221 | The remote stub understands the @samp{qXfer:osdata:read} packet | |
29222 | ((@pxref{qXfer osdata read}). | |
29223 | ||
782b2b07 SS |
29224 | @item ConditionalTracepoints |
29225 | The remote stub accepts and implements conditional expressions defined | |
29226 | for tracepoints (@pxref{Tracepoint Conditions}). | |
29227 | ||
0d772ac9 MS |
29228 | @item ReverseContinue |
29229 | The remote stub accepts and implements the reverse continue packet | |
29230 | (@pxref{bc}). | |
29231 | ||
29232 | @item ReverseStep | |
29233 | The remote stub accepts and implements the reverse step packet | |
29234 | (@pxref{bs}). | |
29235 | ||
be2a5f71 DJ |
29236 | @end table |
29237 | ||
b8ff78ce | 29238 | @item qSymbol:: |
ff2587ec | 29239 | @cindex symbol lookup, remote request |
b8ff78ce | 29240 | @cindex @samp{qSymbol} packet |
ff2587ec WZ |
29241 | Notify the target that @value{GDBN} is prepared to serve symbol lookup |
29242 | requests. Accept requests from the target for the values of symbols. | |
fa93a9d8 JB |
29243 | |
29244 | Reply: | |
ff2587ec | 29245 | @table @samp |
b8ff78ce | 29246 | @item OK |
ff2587ec | 29247 | The target does not need to look up any (more) symbols. |
b8ff78ce | 29248 | @item qSymbol:@var{sym_name} |
ff2587ec WZ |
29249 | The target requests the value of symbol @var{sym_name} (hex encoded). |
29250 | @value{GDBN} may provide the value by using the | |
b8ff78ce JB |
29251 | @samp{qSymbol:@var{sym_value}:@var{sym_name}} message, described |
29252 | below. | |
ff2587ec | 29253 | @end table |
83761cbd | 29254 | |
b8ff78ce | 29255 | @item qSymbol:@var{sym_value}:@var{sym_name} |
ff2587ec WZ |
29256 | Set the value of @var{sym_name} to @var{sym_value}. |
29257 | ||
29258 | @var{sym_name} (hex encoded) is the name of a symbol whose value the | |
29259 | target has previously requested. | |
29260 | ||
29261 | @var{sym_value} (hex) is the value for symbol @var{sym_name}. If | |
29262 | @value{GDBN} cannot supply a value for @var{sym_name}, then this field | |
29263 | will be empty. | |
29264 | ||
29265 | Reply: | |
29266 | @table @samp | |
b8ff78ce | 29267 | @item OK |
ff2587ec | 29268 | The target does not need to look up any (more) symbols. |
b8ff78ce | 29269 | @item qSymbol:@var{sym_name} |
ff2587ec WZ |
29270 | The target requests the value of a new symbol @var{sym_name} (hex |
29271 | encoded). @value{GDBN} will continue to supply the values of symbols | |
29272 | (if available), until the target ceases to request them. | |
fa93a9d8 | 29273 | @end table |
0abb7bc7 | 29274 | |
9d29849a JB |
29275 | @item QTDP |
29276 | @itemx QTFrame | |
29277 | @xref{Tracepoint Packets}. | |
29278 | ||
b90a069a | 29279 | @item qThreadExtraInfo,@var{thread-id} |
ff2587ec | 29280 | @cindex thread attributes info, remote request |
b8ff78ce JB |
29281 | @cindex @samp{qThreadExtraInfo} packet |
29282 | Obtain a printable string description of a thread's attributes from | |
b90a069a SL |
29283 | the target OS. @var{thread-id} is a thread ID; |
29284 | see @ref{thread-id syntax}. This | |
b8ff78ce JB |
29285 | string may contain anything that the target OS thinks is interesting |
29286 | for @value{GDBN} to tell the user about the thread. The string is | |
29287 | displayed in @value{GDBN}'s @code{info threads} display. Some | |
29288 | examples of possible thread extra info strings are @samp{Runnable}, or | |
29289 | @samp{Blocked on Mutex}. | |
ff2587ec WZ |
29290 | |
29291 | Reply: | |
29292 | @table @samp | |
b8ff78ce JB |
29293 | @item @var{XX}@dots{} |
29294 | Where @samp{@var{XX}@dots{}} is a hex encoding of @sc{ascii} data, | |
29295 | comprising the printable string containing the extra information about | |
29296 | the thread's attributes. | |
ff2587ec | 29297 | @end table |
814e32d7 | 29298 | |
aa56d27a JB |
29299 | (Note that the @code{qThreadExtraInfo} packet's name is separated from |
29300 | the command by a @samp{,}, not a @samp{:}, contrary to the naming | |
29301 | conventions above. Please don't use this packet as a model for new | |
29302 | packets.) | |
29303 | ||
9d29849a JB |
29304 | @item QTStart |
29305 | @itemx QTStop | |
29306 | @itemx QTinit | |
29307 | @itemx QTro | |
29308 | @itemx qTStatus | |
29309 | @xref{Tracepoint Packets}. | |
29310 | ||
0876f84a DJ |
29311 | @item qXfer:@var{object}:read:@var{annex}:@var{offset},@var{length} |
29312 | @cindex read special object, remote request | |
29313 | @cindex @samp{qXfer} packet | |
68437a39 | 29314 | @anchor{qXfer read} |
0876f84a DJ |
29315 | Read uninterpreted bytes from the target's special data area |
29316 | identified by the keyword @var{object}. Request @var{length} bytes | |
29317 | starting at @var{offset} bytes into the data. The content and | |
0e7f50da | 29318 | encoding of @var{annex} is specific to @var{object}; it can supply |
0876f84a DJ |
29319 | additional details about what data to access. |
29320 | ||
29321 | Here are the specific requests of this form defined so far. All | |
29322 | @samp{qXfer:@var{object}:read:@dots{}} requests use the same reply | |
29323 | formats, listed below. | |
29324 | ||
29325 | @table @samp | |
29326 | @item qXfer:auxv:read::@var{offset},@var{length} | |
29327 | @anchor{qXfer auxiliary vector read} | |
29328 | Access the target's @dfn{auxiliary vector}. @xref{OS Information, | |
427c3a89 | 29329 | auxiliary vector}. Note @var{annex} must be empty. |
0876f84a DJ |
29330 | |
29331 | This packet is not probed by default; the remote stub must request it, | |
89be2091 | 29332 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). |
0876f84a | 29333 | |
23181151 DJ |
29334 | @item qXfer:features:read:@var{annex}:@var{offset},@var{length} |
29335 | @anchor{qXfer target description read} | |
29336 | Access the @dfn{target description}. @xref{Target Descriptions}. The | |
29337 | annex specifies which XML document to access. The main description is | |
29338 | always loaded from the @samp{target.xml} annex. | |
29339 | ||
29340 | This packet is not probed by default; the remote stub must request it, | |
29341 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29342 | ||
cfa9d6d9 DJ |
29343 | @item qXfer:libraries:read:@var{annex}:@var{offset},@var{length} |
29344 | @anchor{qXfer library list read} | |
29345 | Access the target's list of loaded libraries. @xref{Library List Format}. | |
29346 | The annex part of the generic @samp{qXfer} packet must be empty | |
29347 | (@pxref{qXfer read}). | |
29348 | ||
29349 | Targets which maintain a list of libraries in the program's memory do | |
29350 | not need to implement this packet; it is designed for platforms where | |
29351 | the operating system manages the list of loaded libraries. | |
29352 | ||
29353 | This packet is not probed by default; the remote stub must request it, | |
29354 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29355 | ||
68437a39 DJ |
29356 | @item qXfer:memory-map:read::@var{offset},@var{length} |
29357 | @anchor{qXfer memory map read} | |
79a6e687 | 29358 | Access the target's @dfn{memory-map}. @xref{Memory Map Format}. The |
68437a39 DJ |
29359 | annex part of the generic @samp{qXfer} packet must be empty |
29360 | (@pxref{qXfer read}). | |
29361 | ||
0e7f50da UW |
29362 | This packet is not probed by default; the remote stub must request it, |
29363 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29364 | ||
4aa995e1 PA |
29365 | @item qXfer:siginfo:read::@var{offset},@var{length} |
29366 | @anchor{qXfer siginfo read} | |
29367 | Read contents of the extra signal information on the target | |
29368 | system. The annex part of the generic @samp{qXfer} packet must be | |
29369 | empty (@pxref{qXfer read}). | |
29370 | ||
29371 | This packet is not probed by default; the remote stub must request it, | |
29372 | by supplying an appropriate @samp{qSupported} response | |
29373 | (@pxref{qSupported}). | |
29374 | ||
0e7f50da UW |
29375 | @item qXfer:spu:read:@var{annex}:@var{offset},@var{length} |
29376 | @anchor{qXfer spu read} | |
29377 | Read contents of an @code{spufs} file on the target system. The | |
29378 | annex specifies which file to read; it must be of the form | |
29379 | @file{@var{id}/@var{name}}, where @var{id} specifies an SPU context ID | |
29380 | in the target process, and @var{name} identifes the @code{spufs} file | |
29381 | in that context to be accessed. | |
29382 | ||
68437a39 | 29383 | This packet is not probed by default; the remote stub must request it, |
07e059b5 VP |
29384 | by supplying an appropriate @samp{qSupported} response |
29385 | (@pxref{qSupported}). | |
29386 | ||
29387 | @item qXfer:osdata:read::@var{offset},@var{length} | |
29388 | @anchor{qXfer osdata read} | |
29389 | Access the target's @dfn{operating system information}. | |
29390 | @xref{Operating System Information}. | |
29391 | ||
68437a39 DJ |
29392 | @end table |
29393 | ||
0876f84a DJ |
29394 | Reply: |
29395 | @table @samp | |
29396 | @item m @var{data} | |
29397 | Data @var{data} (@pxref{Binary Data}) has been read from the | |
29398 | target. There may be more data at a higher address (although | |
29399 | it is permitted to return @samp{m} even for the last valid | |
29400 | block of data, as long as at least one byte of data was read). | |
29401 | @var{data} may have fewer bytes than the @var{length} in the | |
29402 | request. | |
29403 | ||
29404 | @item l @var{data} | |
29405 | Data @var{data} (@pxref{Binary Data}) has been read from the target. | |
29406 | There is no more data to be read. @var{data} may have fewer bytes | |
29407 | than the @var{length} in the request. | |
29408 | ||
29409 | @item l | |
29410 | The @var{offset} in the request is at the end of the data. | |
29411 | There is no more data to be read. | |
29412 | ||
29413 | @item E00 | |
29414 | The request was malformed, or @var{annex} was invalid. | |
29415 | ||
29416 | @item E @var{nn} | |
29417 | The offset was invalid, or there was an error encountered reading the data. | |
29418 | @var{nn} is a hex-encoded @code{errno} value. | |
29419 | ||
29420 | @item | |
29421 | An empty reply indicates the @var{object} string was not recognized by | |
29422 | the stub, or that the object does not support reading. | |
29423 | @end table | |
29424 | ||
29425 | @item qXfer:@var{object}:write:@var{annex}:@var{offset}:@var{data}@dots{} | |
29426 | @cindex write data into object, remote request | |
4aa995e1 | 29427 | @anchor{qXfer write} |
0876f84a DJ |
29428 | Write uninterpreted bytes into the target's special data area |
29429 | identified by the keyword @var{object}, starting at @var{offset} bytes | |
0e7f50da | 29430 | into the data. @var{data}@dots{} is the binary-encoded data |
0876f84a | 29431 | (@pxref{Binary Data}) to be written. The content and encoding of @var{annex} |
0e7f50da | 29432 | is specific to @var{object}; it can supply additional details about what data |
0876f84a DJ |
29433 | to access. |
29434 | ||
0e7f50da UW |
29435 | Here are the specific requests of this form defined so far. All |
29436 | @samp{qXfer:@var{object}:write:@dots{}} requests use the same reply | |
29437 | formats, listed below. | |
29438 | ||
29439 | @table @samp | |
4aa995e1 PA |
29440 | @item qXfer:siginfo:write::@var{offset}:@var{data}@dots{} |
29441 | @anchor{qXfer siginfo write} | |
29442 | Write @var{data} to the extra signal information on the target system. | |
29443 | The annex part of the generic @samp{qXfer} packet must be | |
29444 | empty (@pxref{qXfer write}). | |
29445 | ||
29446 | This packet is not probed by default; the remote stub must request it, | |
29447 | by supplying an appropriate @samp{qSupported} response | |
29448 | (@pxref{qSupported}). | |
29449 | ||
84fcdf95 | 29450 | @item qXfer:spu:write:@var{annex}:@var{offset}:@var{data}@dots{} |
0e7f50da UW |
29451 | @anchor{qXfer spu write} |
29452 | Write @var{data} to an @code{spufs} file on the target system. The | |
29453 | annex specifies which file to write; it must be of the form | |
29454 | @file{@var{id}/@var{name}}, where @var{id} specifies an SPU context ID | |
29455 | in the target process, and @var{name} identifes the @code{spufs} file | |
29456 | in that context to be accessed. | |
29457 | ||
29458 | This packet is not probed by default; the remote stub must request it, | |
29459 | by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}). | |
29460 | @end table | |
0876f84a DJ |
29461 | |
29462 | Reply: | |
29463 | @table @samp | |
29464 | @item @var{nn} | |
29465 | @var{nn} (hex encoded) is the number of bytes written. | |
29466 | This may be fewer bytes than supplied in the request. | |
29467 | ||
29468 | @item E00 | |
29469 | The request was malformed, or @var{annex} was invalid. | |
29470 | ||
29471 | @item E @var{nn} | |
29472 | The offset was invalid, or there was an error encountered writing the data. | |
29473 | @var{nn} is a hex-encoded @code{errno} value. | |
29474 | ||
29475 | @item | |
29476 | An empty reply indicates the @var{object} string was not | |
29477 | recognized by the stub, or that the object does not support writing. | |
29478 | @end table | |
29479 | ||
29480 | @item qXfer:@var{object}:@var{operation}:@dots{} | |
29481 | Requests of this form may be added in the future. When a stub does | |
29482 | not recognize the @var{object} keyword, or its support for | |
29483 | @var{object} does not recognize the @var{operation} keyword, the stub | |
29484 | must respond with an empty packet. | |
29485 | ||
0b16c5cf PA |
29486 | @item qAttached:@var{pid} |
29487 | @cindex query attached, remote request | |
29488 | @cindex @samp{qAttached} packet | |
29489 | Return an indication of whether the remote server attached to an | |
29490 | existing process or created a new process. When the multiprocess | |
29491 | protocol extensions are supported (@pxref{multiprocess extensions}), | |
29492 | @var{pid} is an integer in hexadecimal format identifying the target | |
29493 | process. Otherwise, @value{GDBN} will omit the @var{pid} field and | |
29494 | the query packet will be simplified as @samp{qAttached}. | |
29495 | ||
29496 | This query is used, for example, to know whether the remote process | |
29497 | should be detached or killed when a @value{GDBN} session is ended with | |
29498 | the @code{quit} command. | |
29499 | ||
29500 | Reply: | |
29501 | @table @samp | |
29502 | @item 1 | |
29503 | The remote server attached to an existing process. | |
29504 | @item 0 | |
29505 | The remote server created a new process. | |
29506 | @item E @var{NN} | |
29507 | A badly formed request or an error was encountered. | |
29508 | @end table | |
29509 | ||
ee2d5c50 AC |
29510 | @end table |
29511 | ||
29512 | @node Register Packet Format | |
29513 | @section Register Packet Format | |
eb12ee30 | 29514 | |
b8ff78ce | 29515 | The following @code{g}/@code{G} packets have previously been defined. |
ee2d5c50 AC |
29516 | In the below, some thirty-two bit registers are transferred as |
29517 | sixty-four bits. Those registers should be zero/sign extended (which?) | |
599b237a BW |
29518 | to fill the space allocated. Register bytes are transferred in target |
29519 | byte order. The two nibbles within a register byte are transferred | |
ee2d5c50 | 29520 | most-significant - least-significant. |
eb12ee30 | 29521 | |
ee2d5c50 | 29522 | @table @r |
eb12ee30 | 29523 | |
8e04817f | 29524 | @item MIPS32 |
ee2d5c50 | 29525 | |
599b237a | 29526 | All registers are transferred as thirty-two bit quantities in the order: |
8e04817f AC |
29527 | 32 general-purpose; sr; lo; hi; bad; cause; pc; 32 floating-point |
29528 | registers; fsr; fir; fp. | |
eb12ee30 | 29529 | |
8e04817f | 29530 | @item MIPS64 |
ee2d5c50 | 29531 | |
599b237a | 29532 | All registers are transferred as sixty-four bit quantities (including |
8e04817f AC |
29533 | thirty-two bit registers such as @code{sr}). The ordering is the same |
29534 | as @code{MIPS32}. | |
eb12ee30 | 29535 | |
ee2d5c50 AC |
29536 | @end table |
29537 | ||
9d29849a JB |
29538 | @node Tracepoint Packets |
29539 | @section Tracepoint Packets | |
29540 | @cindex tracepoint packets | |
29541 | @cindex packets, tracepoint | |
29542 | ||
29543 | Here we describe the packets @value{GDBN} uses to implement | |
29544 | tracepoints (@pxref{Tracepoints}). | |
29545 | ||
29546 | @table @samp | |
29547 | ||
782b2b07 | 29548 | @item QTDP:@var{n}:@var{addr}:@var{ena}:@var{step}:@var{pass}[:X@var{len},@var{bytes}]@r{[}-@r{]} |
9d29849a JB |
29549 | Create a new tracepoint, number @var{n}, at @var{addr}. If @var{ena} |
29550 | is @samp{E}, then the tracepoint is enabled; if it is @samp{D}, then | |
29551 | the tracepoint is disabled. @var{step} is the tracepoint's step | |
782b2b07 SS |
29552 | count, and @var{pass} is its pass count. If an @samp{X} is present, |
29553 | it introduces a tracepoint condition, which consists of a hexadecimal | |
29554 | length, followed by a comma and hex-encoded bytes, in a manner similar | |
29555 | to action encodings as described below. If the trailing @samp{-} is | |
9d29849a JB |
29556 | present, further @samp{QTDP} packets will follow to specify this |
29557 | tracepoint's actions. | |
29558 | ||
29559 | Replies: | |
29560 | @table @samp | |
29561 | @item OK | |
29562 | The packet was understood and carried out. | |
29563 | @item | |
29564 | The packet was not recognized. | |
29565 | @end table | |
29566 | ||
29567 | @item QTDP:-@var{n}:@var{addr}:@r{[}S@r{]}@var{action}@dots{}@r{[}-@r{]} | |
29568 | Define actions to be taken when a tracepoint is hit. @var{n} and | |
29569 | @var{addr} must be the same as in the initial @samp{QTDP} packet for | |
29570 | this tracepoint. This packet may only be sent immediately after | |
29571 | another @samp{QTDP} packet that ended with a @samp{-}. If the | |
29572 | trailing @samp{-} is present, further @samp{QTDP} packets will follow, | |
29573 | specifying more actions for this tracepoint. | |
29574 | ||
29575 | In the series of action packets for a given tracepoint, at most one | |
29576 | can have an @samp{S} before its first @var{action}. If such a packet | |
29577 | is sent, it and the following packets define ``while-stepping'' | |
29578 | actions. Any prior packets define ordinary actions --- that is, those | |
29579 | taken when the tracepoint is first hit. If no action packet has an | |
29580 | @samp{S}, then all the packets in the series specify ordinary | |
29581 | tracepoint actions. | |
29582 | ||
29583 | The @samp{@var{action}@dots{}} portion of the packet is a series of | |
29584 | actions, concatenated without separators. Each action has one of the | |
29585 | following forms: | |
29586 | ||
29587 | @table @samp | |
29588 | ||
29589 | @item R @var{mask} | |
29590 | Collect the registers whose bits are set in @var{mask}. @var{mask} is | |
599b237a | 29591 | a hexadecimal number whose @var{i}'th bit is set if register number |
9d29849a JB |
29592 | @var{i} should be collected. (The least significant bit is numbered |
29593 | zero.) Note that @var{mask} may be any number of digits long; it may | |
29594 | not fit in a 32-bit word. | |
29595 | ||
29596 | @item M @var{basereg},@var{offset},@var{len} | |
29597 | Collect @var{len} bytes of memory starting at the address in register | |
29598 | number @var{basereg}, plus @var{offset}. If @var{basereg} is | |
29599 | @samp{-1}, then the range has a fixed address: @var{offset} is the | |
29600 | address of the lowest byte to collect. The @var{basereg}, | |
599b237a | 29601 | @var{offset}, and @var{len} parameters are all unsigned hexadecimal |
9d29849a JB |
29602 | values (the @samp{-1} value for @var{basereg} is a special case). |
29603 | ||
29604 | @item X @var{len},@var{expr} | |
29605 | Evaluate @var{expr}, whose length is @var{len}, and collect memory as | |
29606 | it directs. @var{expr} is an agent expression, as described in | |
29607 | @ref{Agent Expressions}. Each byte of the expression is encoded as a | |
29608 | two-digit hex number in the packet; @var{len} is the number of bytes | |
29609 | in the expression (and thus one-half the number of hex digits in the | |
29610 | packet). | |
29611 | ||
29612 | @end table | |
29613 | ||
29614 | Any number of actions may be packed together in a single @samp{QTDP} | |
29615 | packet, as long as the packet does not exceed the maximum packet | |
c1947b85 JB |
29616 | length (400 bytes, for many stubs). There may be only one @samp{R} |
29617 | action per tracepoint, and it must precede any @samp{M} or @samp{X} | |
29618 | actions. Any registers referred to by @samp{M} and @samp{X} actions | |
29619 | must be collected by a preceding @samp{R} action. (The | |
29620 | ``while-stepping'' actions are treated as if they were attached to a | |
29621 | separate tracepoint, as far as these restrictions are concerned.) | |
9d29849a JB |
29622 | |
29623 | Replies: | |
29624 | @table @samp | |
29625 | @item OK | |
29626 | The packet was understood and carried out. | |
29627 | @item | |
29628 | The packet was not recognized. | |
29629 | @end table | |
29630 | ||
29631 | @item QTFrame:@var{n} | |
29632 | Select the @var{n}'th tracepoint frame from the buffer, and use the | |
29633 | register and memory contents recorded there to answer subsequent | |
29634 | request packets from @value{GDBN}. | |
29635 | ||
29636 | A successful reply from the stub indicates that the stub has found the | |
29637 | requested frame. The response is a series of parts, concatenated | |
29638 | without separators, describing the frame we selected. Each part has | |
29639 | one of the following forms: | |
29640 | ||
29641 | @table @samp | |
29642 | @item F @var{f} | |
29643 | The selected frame is number @var{n} in the trace frame buffer; | |
599b237a | 29644 | @var{f} is a hexadecimal number. If @var{f} is @samp{-1}, then there |
9d29849a JB |
29645 | was no frame matching the criteria in the request packet. |
29646 | ||
29647 | @item T @var{t} | |
29648 | The selected trace frame records a hit of tracepoint number @var{t}; | |
599b237a | 29649 | @var{t} is a hexadecimal number. |
9d29849a JB |
29650 | |
29651 | @end table | |
29652 | ||
29653 | @item QTFrame:pc:@var{addr} | |
29654 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
29655 | currently selected frame whose PC is @var{addr}; | |
599b237a | 29656 | @var{addr} is a hexadecimal number. |
9d29849a JB |
29657 | |
29658 | @item QTFrame:tdp:@var{t} | |
29659 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
29660 | currently selected frame that is a hit of tracepoint @var{t}; @var{t} | |
599b237a | 29661 | is a hexadecimal number. |
9d29849a JB |
29662 | |
29663 | @item QTFrame:range:@var{start}:@var{end} | |
29664 | Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the | |
29665 | currently selected frame whose PC is between @var{start} (inclusive) | |
599b237a | 29666 | and @var{end} (exclusive); @var{start} and @var{end} are hexadecimal |
9d29849a JB |
29667 | numbers. |
29668 | ||
29669 | @item QTFrame:outside:@var{start}:@var{end} | |
29670 | Like @samp{QTFrame:range:@var{start}:@var{end}}, but select the first | |
29671 | frame @emph{outside} the given range of addresses. | |
29672 | ||
29673 | @item QTStart | |
29674 | Begin the tracepoint experiment. Begin collecting data from tracepoint | |
29675 | hits in the trace frame buffer. | |
29676 | ||
29677 | @item QTStop | |
29678 | End the tracepoint experiment. Stop collecting trace frames. | |
29679 | ||
29680 | @item QTinit | |
29681 | Clear the table of tracepoints, and empty the trace frame buffer. | |
29682 | ||
29683 | @item QTro:@var{start1},@var{end1}:@var{start2},@var{end2}:@dots{} | |
29684 | Establish the given ranges of memory as ``transparent''. The stub | |
29685 | will answer requests for these ranges from memory's current contents, | |
29686 | if they were not collected as part of the tracepoint hit. | |
29687 | ||
29688 | @value{GDBN} uses this to mark read-only regions of memory, like those | |
29689 | containing program code. Since these areas never change, they should | |
29690 | still have the same contents they did when the tracepoint was hit, so | |
29691 | there's no reason for the stub to refuse to provide their contents. | |
29692 | ||
29693 | @item qTStatus | |
29694 | Ask the stub if there is a trace experiment running right now. | |
29695 | ||
29696 | Replies: | |
29697 | @table @samp | |
29698 | @item T0 | |
29699 | There is no trace experiment running. | |
29700 | @item T1 | |
29701 | There is a trace experiment running. | |
29702 | @end table | |
29703 | ||
29704 | @end table | |
29705 | ||
29706 | ||
a6b151f1 DJ |
29707 | @node Host I/O Packets |
29708 | @section Host I/O Packets | |
29709 | @cindex Host I/O, remote protocol | |
29710 | @cindex file transfer, remote protocol | |
29711 | ||
29712 | The @dfn{Host I/O} packets allow @value{GDBN} to perform I/O | |
29713 | operations on the far side of a remote link. For example, Host I/O is | |
29714 | used to upload and download files to a remote target with its own | |
29715 | filesystem. Host I/O uses the same constant values and data structure | |
29716 | layout as the target-initiated File-I/O protocol. However, the | |
29717 | Host I/O packets are structured differently. The target-initiated | |
29718 | protocol relies on target memory to store parameters and buffers. | |
29719 | Host I/O requests are initiated by @value{GDBN}, and the | |
29720 | target's memory is not involved. @xref{File-I/O Remote Protocol | |
29721 | Extension}, for more details on the target-initiated protocol. | |
29722 | ||
29723 | The Host I/O request packets all encode a single operation along with | |
29724 | its arguments. They have this format: | |
29725 | ||
29726 | @table @samp | |
29727 | ||
29728 | @item vFile:@var{operation}: @var{parameter}@dots{} | |
29729 | @var{operation} is the name of the particular request; the target | |
29730 | should compare the entire packet name up to the second colon when checking | |
29731 | for a supported operation. The format of @var{parameter} depends on | |
29732 | the operation. Numbers are always passed in hexadecimal. Negative | |
29733 | numbers have an explicit minus sign (i.e.@: two's complement is not | |
29734 | used). Strings (e.g.@: filenames) are encoded as a series of | |
29735 | hexadecimal bytes. The last argument to a system call may be a | |
29736 | buffer of escaped binary data (@pxref{Binary Data}). | |
29737 | ||
29738 | @end table | |
29739 | ||
29740 | The valid responses to Host I/O packets are: | |
29741 | ||
29742 | @table @samp | |
29743 | ||
29744 | @item F @var{result} [, @var{errno}] [; @var{attachment}] | |
29745 | @var{result} is the integer value returned by this operation, usually | |
29746 | non-negative for success and -1 for errors. If an error has occured, | |
29747 | @var{errno} will be included in the result. @var{errno} will have a | |
29748 | value defined by the File-I/O protocol (@pxref{Errno Values}). For | |
29749 | operations which return data, @var{attachment} supplies the data as a | |
29750 | binary buffer. Binary buffers in response packets are escaped in the | |
29751 | normal way (@pxref{Binary Data}). See the individual packet | |
29752 | documentation for the interpretation of @var{result} and | |
29753 | @var{attachment}. | |
29754 | ||
29755 | @item | |
29756 | An empty response indicates that this operation is not recognized. | |
29757 | ||
29758 | @end table | |
29759 | ||
29760 | These are the supported Host I/O operations: | |
29761 | ||
29762 | @table @samp | |
29763 | @item vFile:open: @var{pathname}, @var{flags}, @var{mode} | |
29764 | Open a file at @var{pathname} and return a file descriptor for it, or | |
29765 | return -1 if an error occurs. @var{pathname} is a string, | |
29766 | @var{flags} is an integer indicating a mask of open flags | |
29767 | (@pxref{Open Flags}), and @var{mode} is an integer indicating a mask | |
29768 | of mode bits to use if the file is created (@pxref{mode_t Values}). | |
c1c25a1a | 29769 | @xref{open}, for details of the open flags and mode values. |
a6b151f1 DJ |
29770 | |
29771 | @item vFile:close: @var{fd} | |
29772 | Close the open file corresponding to @var{fd} and return 0, or | |
29773 | -1 if an error occurs. | |
29774 | ||
29775 | @item vFile:pread: @var{fd}, @var{count}, @var{offset} | |
29776 | Read data from the open file corresponding to @var{fd}. Up to | |
29777 | @var{count} bytes will be read from the file, starting at @var{offset} | |
29778 | relative to the start of the file. The target may read fewer bytes; | |
29779 | common reasons include packet size limits and an end-of-file | |
29780 | condition. The number of bytes read is returned. Zero should only be | |
29781 | returned for a successful read at the end of the file, or if | |
29782 | @var{count} was zero. | |
29783 | ||
29784 | The data read should be returned as a binary attachment on success. | |
29785 | If zero bytes were read, the response should include an empty binary | |
29786 | attachment (i.e.@: a trailing semicolon). The return value is the | |
29787 | number of target bytes read; the binary attachment may be longer if | |
29788 | some characters were escaped. | |
29789 | ||
29790 | @item vFile:pwrite: @var{fd}, @var{offset}, @var{data} | |
29791 | Write @var{data} (a binary buffer) to the open file corresponding | |
29792 | to @var{fd}. Start the write at @var{offset} from the start of the | |
29793 | file. Unlike many @code{write} system calls, there is no | |
29794 | separate @var{count} argument; the length of @var{data} in the | |
29795 | packet is used. @samp{vFile:write} returns the number of bytes written, | |
29796 | which may be shorter than the length of @var{data}, or -1 if an | |
29797 | error occurred. | |
29798 | ||
29799 | @item vFile:unlink: @var{pathname} | |
29800 | Delete the file at @var{pathname} on the target. Return 0, | |
29801 | or -1 if an error occurs. @var{pathname} is a string. | |
29802 | ||
29803 | @end table | |
29804 | ||
9a6253be KB |
29805 | @node Interrupts |
29806 | @section Interrupts | |
29807 | @cindex interrupts (remote protocol) | |
29808 | ||
29809 | When a program on the remote target is running, @value{GDBN} may | |
29810 | attempt to interrupt it by sending a @samp{Ctrl-C} or a @code{BREAK}, | |
29811 | control of which is specified via @value{GDBN}'s @samp{remotebreak} | |
29812 | setting (@pxref{set remotebreak}). | |
29813 | ||
29814 | The precise meaning of @code{BREAK} is defined by the transport | |
8775bb90 MS |
29815 | mechanism and may, in fact, be undefined. @value{GDBN} does not |
29816 | currently define a @code{BREAK} mechanism for any of the network | |
29817 | interfaces except for TCP, in which case @value{GDBN} sends the | |
29818 | @code{telnet} BREAK sequence. | |
9a6253be KB |
29819 | |
29820 | @samp{Ctrl-C}, on the other hand, is defined and implemented for all | |
29821 | transport mechanisms. It is represented by sending the single byte | |
29822 | @code{0x03} without any of the usual packet overhead described in | |
29823 | the Overview section (@pxref{Overview}). When a @code{0x03} byte is | |
29824 | transmitted as part of a packet, it is considered to be packet data | |
29825 | and does @emph{not} represent an interrupt. E.g., an @samp{X} packet | |
0876f84a | 29826 | (@pxref{X packet}), used for binary downloads, may include an unescaped |
9a6253be KB |
29827 | @code{0x03} as part of its packet. |
29828 | ||
29829 | Stubs are not required to recognize these interrupt mechanisms and the | |
29830 | precise meaning associated with receipt of the interrupt is | |
8b23ecc4 SL |
29831 | implementation defined. If the target supports debugging of multiple |
29832 | threads and/or processes, it should attempt to interrupt all | |
29833 | currently-executing threads and processes. | |
29834 | If the stub is successful at interrupting the | |
29835 | running program, it should send one of the stop | |
29836 | reply packets (@pxref{Stop Reply Packets}) to @value{GDBN} as a result | |
29837 | of successfully stopping the program in all-stop mode, and a stop reply | |
29838 | for each stopped thread in non-stop mode. | |
29839 | Interrupts received while the | |
29840 | program is stopped are discarded. | |
29841 | ||
29842 | @node Notification Packets | |
29843 | @section Notification Packets | |
29844 | @cindex notification packets | |
29845 | @cindex packets, notification | |
29846 | ||
29847 | The @value{GDBN} remote serial protocol includes @dfn{notifications}, | |
29848 | packets that require no acknowledgment. Both the GDB and the stub | |
29849 | may send notifications (although the only notifications defined at | |
29850 | present are sent by the stub). Notifications carry information | |
29851 | without incurring the round-trip latency of an acknowledgment, and so | |
29852 | are useful for low-impact communications where occasional packet loss | |
29853 | is not a problem. | |
29854 | ||
29855 | A notification packet has the form @samp{% @var{data} # | |
29856 | @var{checksum}}, where @var{data} is the content of the notification, | |
29857 | and @var{checksum} is a checksum of @var{data}, computed and formatted | |
29858 | as for ordinary @value{GDBN} packets. A notification's @var{data} | |
29859 | never contains @samp{$}, @samp{%} or @samp{#} characters. Upon | |
29860 | receiving a notification, the recipient sends no @samp{+} or @samp{-} | |
29861 | to acknowledge the notification's receipt or to report its corruption. | |
29862 | ||
29863 | Every notification's @var{data} begins with a name, which contains no | |
29864 | colon characters, followed by a colon character. | |
29865 | ||
29866 | Recipients should silently ignore corrupted notifications and | |
29867 | notifications they do not understand. Recipients should restart | |
29868 | timeout periods on receipt of a well-formed notification, whether or | |
29869 | not they understand it. | |
29870 | ||
29871 | Senders should only send the notifications described here when this | |
29872 | protocol description specifies that they are permitted. In the | |
29873 | future, we may extend the protocol to permit existing notifications in | |
29874 | new contexts; this rule helps older senders avoid confusing newer | |
29875 | recipients. | |
29876 | ||
29877 | (Older versions of @value{GDBN} ignore bytes received until they see | |
29878 | the @samp{$} byte that begins an ordinary packet, so new stubs may | |
29879 | transmit notifications without fear of confusing older clients. There | |
29880 | are no notifications defined for @value{GDBN} to send at the moment, but we | |
29881 | assume that most older stubs would ignore them, as well.) | |
29882 | ||
29883 | The following notification packets from the stub to @value{GDBN} are | |
29884 | defined: | |
29885 | ||
29886 | @table @samp | |
29887 | @item Stop: @var{reply} | |
29888 | Report an asynchronous stop event in non-stop mode. | |
29889 | The @var{reply} has the form of a stop reply, as | |
29890 | described in @ref{Stop Reply Packets}. Refer to @ref{Remote Non-Stop}, | |
29891 | for information on how these notifications are acknowledged by | |
29892 | @value{GDBN}. | |
29893 | @end table | |
29894 | ||
29895 | @node Remote Non-Stop | |
29896 | @section Remote Protocol Support for Non-Stop Mode | |
29897 | ||
29898 | @value{GDBN}'s remote protocol supports non-stop debugging of | |
29899 | multi-threaded programs, as described in @ref{Non-Stop Mode}. If the stub | |
29900 | supports non-stop mode, it should report that to @value{GDBN} by including | |
29901 | @samp{QNonStop+} in its @samp{qSupported} response (@pxref{qSupported}). | |
29902 | ||
29903 | @value{GDBN} typically sends a @samp{QNonStop} packet only when | |
29904 | establishing a new connection with the stub. Entering non-stop mode | |
29905 | does not alter the state of any currently-running threads, but targets | |
29906 | must stop all threads in any already-attached processes when entering | |
29907 | all-stop mode. @value{GDBN} uses the @samp{?} packet as necessary to | |
29908 | probe the target state after a mode change. | |
29909 | ||
29910 | In non-stop mode, when an attached process encounters an event that | |
29911 | would otherwise be reported with a stop reply, it uses the | |
29912 | asynchronous notification mechanism (@pxref{Notification Packets}) to | |
29913 | inform @value{GDBN}. In contrast to all-stop mode, where all threads | |
29914 | in all processes are stopped when a stop reply is sent, in non-stop | |
29915 | mode only the thread reporting the stop event is stopped. That is, | |
29916 | when reporting a @samp{S} or @samp{T} response to indicate completion | |
29917 | of a step operation, hitting a breakpoint, or a fault, only the | |
29918 | affected thread is stopped; any other still-running threads continue | |
29919 | to run. When reporting a @samp{W} or @samp{X} response, all running | |
29920 | threads belonging to other attached processes continue to run. | |
29921 | ||
29922 | Only one stop reply notification at a time may be pending; if | |
29923 | additional stop events occur before @value{GDBN} has acknowledged the | |
29924 | previous notification, they must be queued by the stub for later | |
29925 | synchronous transmission in response to @samp{vStopped} packets from | |
29926 | @value{GDBN}. Because the notification mechanism is unreliable, | |
29927 | the stub is permitted to resend a stop reply notification | |
29928 | if it believes @value{GDBN} may not have received it. @value{GDBN} | |
29929 | ignores additional stop reply notifications received before it has | |
29930 | finished processing a previous notification and the stub has completed | |
29931 | sending any queued stop events. | |
29932 | ||
29933 | Otherwise, @value{GDBN} must be prepared to receive a stop reply | |
29934 | notification at any time. Specifically, they may appear when | |
29935 | @value{GDBN} is not otherwise reading input from the stub, or when | |
29936 | @value{GDBN} is expecting to read a normal synchronous response or a | |
29937 | @samp{+}/@samp{-} acknowledgment to a packet it has sent. | |
29938 | Notification packets are distinct from any other communication from | |
29939 | the stub so there is no ambiguity. | |
29940 | ||
29941 | After receiving a stop reply notification, @value{GDBN} shall | |
29942 | acknowledge it by sending a @samp{vStopped} packet (@pxref{vStopped packet}) | |
29943 | as a regular, synchronous request to the stub. Such acknowledgment | |
29944 | is not required to happen immediately, as @value{GDBN} is permitted to | |
29945 | send other, unrelated packets to the stub first, which the stub should | |
29946 | process normally. | |
29947 | ||
29948 | Upon receiving a @samp{vStopped} packet, if the stub has other queued | |
29949 | stop events to report to @value{GDBN}, it shall respond by sending a | |
29950 | normal stop reply response. @value{GDBN} shall then send another | |
29951 | @samp{vStopped} packet to solicit further responses; again, it is | |
29952 | permitted to send other, unrelated packets as well which the stub | |
29953 | should process normally. | |
29954 | ||
29955 | If the stub receives a @samp{vStopped} packet and there are no | |
29956 | additional stop events to report, the stub shall return an @samp{OK} | |
29957 | response. At this point, if further stop events occur, the stub shall | |
29958 | send a new stop reply notification, @value{GDBN} shall accept the | |
29959 | notification, and the process shall be repeated. | |
29960 | ||
29961 | In non-stop mode, the target shall respond to the @samp{?} packet as | |
29962 | follows. First, any incomplete stop reply notification/@samp{vStopped} | |
29963 | sequence in progress is abandoned. The target must begin a new | |
29964 | sequence reporting stop events for all stopped threads, whether or not | |
29965 | it has previously reported those events to @value{GDBN}. The first | |
29966 | stop reply is sent as a synchronous reply to the @samp{?} packet, and | |
29967 | subsequent stop replies are sent as responses to @samp{vStopped} packets | |
29968 | using the mechanism described above. The target must not send | |
29969 | asynchronous stop reply notifications until the sequence is complete. | |
29970 | If all threads are running when the target receives the @samp{?} packet, | |
29971 | or if the target is not attached to any process, it shall respond | |
29972 | @samp{OK}. | |
9a6253be | 29973 | |
a6f3e723 SL |
29974 | @node Packet Acknowledgment |
29975 | @section Packet Acknowledgment | |
29976 | ||
29977 | @cindex acknowledgment, for @value{GDBN} remote | |
29978 | @cindex packet acknowledgment, for @value{GDBN} remote | |
29979 | By default, when either the host or the target machine receives a packet, | |
29980 | the first response expected is an acknowledgment: either @samp{+} (to indicate | |
29981 | the package was received correctly) or @samp{-} (to request retransmission). | |
29982 | This mechanism allows the @value{GDBN} remote protocol to operate over | |
29983 | unreliable transport mechanisms, such as a serial line. | |
29984 | ||
29985 | In cases where the transport mechanism is itself reliable (such as a pipe or | |
29986 | TCP connection), the @samp{+}/@samp{-} acknowledgments are redundant. | |
29987 | It may be desirable to disable them in that case to reduce communication | |
29988 | overhead, or for other reasons. This can be accomplished by means of the | |
29989 | @samp{QStartNoAckMode} packet; @pxref{QStartNoAckMode}. | |
29990 | ||
29991 | When in no-acknowledgment mode, neither the stub nor @value{GDBN} shall send or | |
29992 | expect @samp{+}/@samp{-} protocol acknowledgments. The packet | |
29993 | and response format still includes the normal checksum, as described in | |
29994 | @ref{Overview}, but the checksum may be ignored by the receiver. | |
29995 | ||
29996 | If the stub supports @samp{QStartNoAckMode} and prefers to operate in | |
29997 | no-acknowledgment mode, it should report that to @value{GDBN} | |
29998 | by including @samp{QStartNoAckMode+} in its response to @samp{qSupported}; | |
29999 | @pxref{qSupported}. | |
30000 | If @value{GDBN} also supports @samp{QStartNoAckMode} and it has not been | |
30001 | disabled via the @code{set remote noack-packet off} command | |
30002 | (@pxref{Remote Configuration}), | |
30003 | @value{GDBN} may then send a @samp{QStartNoAckMode} packet to the stub. | |
30004 | Only then may the stub actually turn off packet acknowledgments. | |
30005 | @value{GDBN} sends a final @samp{+} acknowledgment of the stub's @samp{OK} | |
30006 | response, which can be safely ignored by the stub. | |
30007 | ||
30008 | Note that @code{set remote noack-packet} command only affects negotiation | |
30009 | between @value{GDBN} and the stub when subsequent connections are made; | |
30010 | it does not affect the protocol acknowledgment state for any current | |
30011 | connection. | |
30012 | Since @samp{+}/@samp{-} acknowledgments are enabled by default when a | |
30013 | new connection is established, | |
30014 | there is also no protocol request to re-enable the acknowledgments | |
30015 | for the current connection, once disabled. | |
30016 | ||
ee2d5c50 AC |
30017 | @node Examples |
30018 | @section Examples | |
eb12ee30 | 30019 | |
8e04817f AC |
30020 | Example sequence of a target being re-started. Notice how the restart |
30021 | does not get any direct output: | |
eb12ee30 | 30022 | |
474c8240 | 30023 | @smallexample |
d2c6833e AC |
30024 | -> @code{R00} |
30025 | <- @code{+} | |
8e04817f | 30026 | @emph{target restarts} |
d2c6833e | 30027 | -> @code{?} |
8e04817f | 30028 | <- @code{+} |
d2c6833e AC |
30029 | <- @code{T001:1234123412341234} |
30030 | -> @code{+} | |
474c8240 | 30031 | @end smallexample |
eb12ee30 | 30032 | |
8e04817f | 30033 | Example sequence of a target being stepped by a single instruction: |
eb12ee30 | 30034 | |
474c8240 | 30035 | @smallexample |
d2c6833e | 30036 | -> @code{G1445@dots{}} |
8e04817f | 30037 | <- @code{+} |
d2c6833e AC |
30038 | -> @code{s} |
30039 | <- @code{+} | |
30040 | @emph{time passes} | |
30041 | <- @code{T001:1234123412341234} | |
8e04817f | 30042 | -> @code{+} |
d2c6833e | 30043 | -> @code{g} |
8e04817f | 30044 | <- @code{+} |
d2c6833e AC |
30045 | <- @code{1455@dots{}} |
30046 | -> @code{+} | |
474c8240 | 30047 | @end smallexample |
eb12ee30 | 30048 | |
79a6e687 BW |
30049 | @node File-I/O Remote Protocol Extension |
30050 | @section File-I/O Remote Protocol Extension | |
0ce1b118 CV |
30051 | @cindex File-I/O remote protocol extension |
30052 | ||
30053 | @menu | |
30054 | * File-I/O Overview:: | |
79a6e687 BW |
30055 | * Protocol Basics:: |
30056 | * The F Request Packet:: | |
30057 | * The F Reply Packet:: | |
30058 | * The Ctrl-C Message:: | |
0ce1b118 | 30059 | * Console I/O:: |
79a6e687 | 30060 | * List of Supported Calls:: |
db2e3e2e | 30061 | * Protocol-specific Representation of Datatypes:: |
0ce1b118 CV |
30062 | * Constants:: |
30063 | * File-I/O Examples:: | |
30064 | @end menu | |
30065 | ||
30066 | @node File-I/O Overview | |
30067 | @subsection File-I/O Overview | |
30068 | @cindex file-i/o overview | |
30069 | ||
9c16f35a | 30070 | The @dfn{File I/O remote protocol extension} (short: File-I/O) allows the |
fc320d37 | 30071 | target to use the host's file system and console I/O to perform various |
0ce1b118 | 30072 | system calls. System calls on the target system are translated into a |
fc320d37 SL |
30073 | remote protocol packet to the host system, which then performs the needed |
30074 | actions and returns a response packet to the target system. | |
0ce1b118 CV |
30075 | This simulates file system operations even on targets that lack file systems. |
30076 | ||
fc320d37 SL |
30077 | The protocol is defined to be independent of both the host and target systems. |
30078 | It uses its own internal representation of datatypes and values. Both | |
0ce1b118 | 30079 | @value{GDBN} and the target's @value{GDBN} stub are responsible for |
fc320d37 SL |
30080 | translating the system-dependent value representations into the internal |
30081 | protocol representations when data is transmitted. | |
0ce1b118 | 30082 | |
fc320d37 SL |
30083 | The communication is synchronous. A system call is possible only when |
30084 | @value{GDBN} is waiting for a response from the @samp{C}, @samp{c}, @samp{S} | |
30085 | or @samp{s} packets. While @value{GDBN} handles the request for a system call, | |
0ce1b118 | 30086 | the target is stopped to allow deterministic access to the target's |
fc320d37 SL |
30087 | memory. Therefore File-I/O is not interruptible by target signals. On |
30088 | the other hand, it is possible to interrupt File-I/O by a user interrupt | |
c8aa23ab | 30089 | (@samp{Ctrl-C}) within @value{GDBN}. |
0ce1b118 CV |
30090 | |
30091 | The target's request to perform a host system call does not finish | |
30092 | the latest @samp{C}, @samp{c}, @samp{S} or @samp{s} action. That means, | |
30093 | after finishing the system call, the target returns to continuing the | |
30094 | previous activity (continue, step). No additional continue or step | |
30095 | request from @value{GDBN} is required. | |
30096 | ||
30097 | @smallexample | |
f7dc1244 | 30098 | (@value{GDBP}) continue |
0ce1b118 CV |
30099 | <- target requests 'system call X' |
30100 | target is stopped, @value{GDBN} executes system call | |
3f94c067 BW |
30101 | -> @value{GDBN} returns result |
30102 | ... target continues, @value{GDBN} returns to wait for the target | |
0ce1b118 CV |
30103 | <- target hits breakpoint and sends a Txx packet |
30104 | @end smallexample | |
30105 | ||
fc320d37 SL |
30106 | The protocol only supports I/O on the console and to regular files on |
30107 | the host file system. Character or block special devices, pipes, | |
30108 | named pipes, sockets or any other communication method on the host | |
0ce1b118 CV |
30109 | system are not supported by this protocol. |
30110 | ||
8b23ecc4 SL |
30111 | File I/O is not supported in non-stop mode. |
30112 | ||
79a6e687 BW |
30113 | @node Protocol Basics |
30114 | @subsection Protocol Basics | |
0ce1b118 CV |
30115 | @cindex protocol basics, file-i/o |
30116 | ||
fc320d37 SL |
30117 | The File-I/O protocol uses the @code{F} packet as the request as well |
30118 | as reply packet. Since a File-I/O system call can only occur when | |
30119 | @value{GDBN} is waiting for a response from the continuing or stepping target, | |
30120 | the File-I/O request is a reply that @value{GDBN} has to expect as a result | |
30121 | of a previous @samp{C}, @samp{c}, @samp{S} or @samp{s} packet. | |
0ce1b118 CV |
30122 | This @code{F} packet contains all information needed to allow @value{GDBN} |
30123 | to call the appropriate host system call: | |
30124 | ||
30125 | @itemize @bullet | |
b383017d | 30126 | @item |
0ce1b118 CV |
30127 | A unique identifier for the requested system call. |
30128 | ||
30129 | @item | |
30130 | All parameters to the system call. Pointers are given as addresses | |
30131 | in the target memory address space. Pointers to strings are given as | |
b383017d | 30132 | pointer/length pair. Numerical values are given as they are. |
db2e3e2e | 30133 | Numerical control flags are given in a protocol-specific representation. |
0ce1b118 CV |
30134 | |
30135 | @end itemize | |
30136 | ||
fc320d37 | 30137 | At this point, @value{GDBN} has to perform the following actions. |
0ce1b118 CV |
30138 | |
30139 | @itemize @bullet | |
b383017d | 30140 | @item |
fc320d37 SL |
30141 | If the parameters include pointer values to data needed as input to a |
30142 | system call, @value{GDBN} requests this data from the target with a | |
0ce1b118 CV |
30143 | standard @code{m} packet request. This additional communication has to be |
30144 | expected by the target implementation and is handled as any other @code{m} | |
30145 | packet. | |
30146 | ||
30147 | @item | |
30148 | @value{GDBN} translates all value from protocol representation to host | |
30149 | representation as needed. Datatypes are coerced into the host types. | |
30150 | ||
30151 | @item | |
fc320d37 | 30152 | @value{GDBN} calls the system call. |
0ce1b118 CV |
30153 | |
30154 | @item | |
30155 | It then coerces datatypes back to protocol representation. | |
30156 | ||
30157 | @item | |
fc320d37 SL |
30158 | If the system call is expected to return data in buffer space specified |
30159 | by pointer parameters to the call, the data is transmitted to the | |
0ce1b118 CV |
30160 | target using a @code{M} or @code{X} packet. This packet has to be expected |
30161 | by the target implementation and is handled as any other @code{M} or @code{X} | |
30162 | packet. | |
30163 | ||
30164 | @end itemize | |
30165 | ||
30166 | Eventually @value{GDBN} replies with another @code{F} packet which contains all | |
30167 | necessary information for the target to continue. This at least contains | |
30168 | ||
30169 | @itemize @bullet | |
30170 | @item | |
30171 | Return value. | |
30172 | ||
30173 | @item | |
30174 | @code{errno}, if has been changed by the system call. | |
30175 | ||
30176 | @item | |
30177 | ``Ctrl-C'' flag. | |
30178 | ||
30179 | @end itemize | |
30180 | ||
30181 | After having done the needed type and value coercion, the target continues | |
30182 | the latest continue or step action. | |
30183 | ||
79a6e687 BW |
30184 | @node The F Request Packet |
30185 | @subsection The @code{F} Request Packet | |
0ce1b118 CV |
30186 | @cindex file-i/o request packet |
30187 | @cindex @code{F} request packet | |
30188 | ||
30189 | The @code{F} request packet has the following format: | |
30190 | ||
30191 | @table @samp | |
fc320d37 | 30192 | @item F@var{call-id},@var{parameter@dots{}} |
0ce1b118 CV |
30193 | |
30194 | @var{call-id} is the identifier to indicate the host system call to be called. | |
30195 | This is just the name of the function. | |
30196 | ||
fc320d37 SL |
30197 | @var{parameter@dots{}} are the parameters to the system call. |
30198 | Parameters are hexadecimal integer values, either the actual values in case | |
30199 | of scalar datatypes, pointers to target buffer space in case of compound | |
30200 | datatypes and unspecified memory areas, or pointer/length pairs in case | |
30201 | of string parameters. These are appended to the @var{call-id} as a | |
30202 | comma-delimited list. All values are transmitted in ASCII | |
30203 | string representation, pointer/length pairs separated by a slash. | |
0ce1b118 | 30204 | |
b383017d | 30205 | @end table |
0ce1b118 | 30206 | |
fc320d37 | 30207 | |
0ce1b118 | 30208 | |
79a6e687 BW |
30209 | @node The F Reply Packet |
30210 | @subsection The @code{F} Reply Packet | |
0ce1b118 CV |
30211 | @cindex file-i/o reply packet |
30212 | @cindex @code{F} reply packet | |
30213 | ||
30214 | The @code{F} reply packet has the following format: | |
30215 | ||
30216 | @table @samp | |
30217 | ||
d3bdde98 | 30218 | @item F@var{retcode},@var{errno},@var{Ctrl-C flag};@var{call-specific attachment} |
0ce1b118 CV |
30219 | |
30220 | @var{retcode} is the return code of the system call as hexadecimal value. | |
30221 | ||
db2e3e2e BW |
30222 | @var{errno} is the @code{errno} set by the call, in protocol-specific |
30223 | representation. | |
0ce1b118 CV |
30224 | This parameter can be omitted if the call was successful. |
30225 | ||
fc320d37 SL |
30226 | @var{Ctrl-C flag} is only sent if the user requested a break. In this |
30227 | case, @var{errno} must be sent as well, even if the call was successful. | |
30228 | The @var{Ctrl-C flag} itself consists of the character @samp{C}: | |
0ce1b118 CV |
30229 | |
30230 | @smallexample | |
30231 | F0,0,C | |
30232 | @end smallexample | |
30233 | ||
30234 | @noindent | |
fc320d37 | 30235 | or, if the call was interrupted before the host call has been performed: |
0ce1b118 CV |
30236 | |
30237 | @smallexample | |
30238 | F-1,4,C | |
30239 | @end smallexample | |
30240 | ||
30241 | @noindent | |
db2e3e2e | 30242 | assuming 4 is the protocol-specific representation of @code{EINTR}. |
0ce1b118 CV |
30243 | |
30244 | @end table | |
30245 | ||
0ce1b118 | 30246 | |
79a6e687 BW |
30247 | @node The Ctrl-C Message |
30248 | @subsection The @samp{Ctrl-C} Message | |
0ce1b118 CV |
30249 | @cindex ctrl-c message, in file-i/o protocol |
30250 | ||
c8aa23ab | 30251 | If the @samp{Ctrl-C} flag is set in the @value{GDBN} |
79a6e687 | 30252 | reply packet (@pxref{The F Reply Packet}), |
fc320d37 | 30253 | the target should behave as if it had |
0ce1b118 | 30254 | gotten a break message. The meaning for the target is ``system call |
fc320d37 | 30255 | interrupted by @code{SIGINT}''. Consequentially, the target should actually stop |
0ce1b118 | 30256 | (as with a break message) and return to @value{GDBN} with a @code{T02} |
c8aa23ab | 30257 | packet. |
fc320d37 SL |
30258 | |
30259 | It's important for the target to know in which | |
30260 | state the system call was interrupted. There are two possible cases: | |
0ce1b118 CV |
30261 | |
30262 | @itemize @bullet | |
30263 | @item | |
30264 | The system call hasn't been performed on the host yet. | |
30265 | ||
30266 | @item | |
30267 | The system call on the host has been finished. | |
30268 | ||
30269 | @end itemize | |
30270 | ||
30271 | These two states can be distinguished by the target by the value of the | |
30272 | returned @code{errno}. If it's the protocol representation of @code{EINTR}, the system | |
30273 | call hasn't been performed. This is equivalent to the @code{EINTR} handling | |
30274 | on POSIX systems. In any other case, the target may presume that the | |
fc320d37 | 30275 | system call has been finished --- successfully or not --- and should behave |
0ce1b118 CV |
30276 | as if the break message arrived right after the system call. |
30277 | ||
fc320d37 | 30278 | @value{GDBN} must behave reliably. If the system call has not been called |
0ce1b118 CV |
30279 | yet, @value{GDBN} may send the @code{F} reply immediately, setting @code{EINTR} as |
30280 | @code{errno} in the packet. If the system call on the host has been finished | |
fc320d37 SL |
30281 | before the user requests a break, the full action must be finished by |
30282 | @value{GDBN}. This requires sending @code{M} or @code{X} packets as necessary. | |
30283 | The @code{F} packet may only be sent when either nothing has happened | |
0ce1b118 CV |
30284 | or the full action has been completed. |
30285 | ||
30286 | @node Console I/O | |
30287 | @subsection Console I/O | |
30288 | @cindex console i/o as part of file-i/o | |
30289 | ||
d3e8051b | 30290 | By default and if not explicitly closed by the target system, the file |
0ce1b118 CV |
30291 | descriptors 0, 1 and 2 are connected to the @value{GDBN} console. Output |
30292 | on the @value{GDBN} console is handled as any other file output operation | |
30293 | (@code{write(1, @dots{})} or @code{write(2, @dots{})}). Console input is handled | |
30294 | by @value{GDBN} so that after the target read request from file descriptor | |
30295 | 0 all following typing is buffered until either one of the following | |
30296 | conditions is met: | |
30297 | ||
30298 | @itemize @bullet | |
30299 | @item | |
c8aa23ab | 30300 | The user types @kbd{Ctrl-c}. The behaviour is as explained above, and the |
0ce1b118 CV |
30301 | @code{read} |
30302 | system call is treated as finished. | |
30303 | ||
30304 | @item | |
7f9087cb | 30305 | The user presses @key{RET}. This is treated as end of input with a trailing |
fc320d37 | 30306 | newline. |
0ce1b118 CV |
30307 | |
30308 | @item | |
c8aa23ab EZ |
30309 | The user types @kbd{Ctrl-d}. This is treated as end of input. No trailing |
30310 | character (neither newline nor @samp{Ctrl-D}) is appended to the input. | |
0ce1b118 CV |
30311 | |
30312 | @end itemize | |
30313 | ||
fc320d37 SL |
30314 | If the user has typed more characters than fit in the buffer given to |
30315 | the @code{read} call, the trailing characters are buffered in @value{GDBN} until | |
30316 | either another @code{read(0, @dots{})} is requested by the target, or debugging | |
30317 | is stopped at the user's request. | |
0ce1b118 | 30318 | |
0ce1b118 | 30319 | |
79a6e687 BW |
30320 | @node List of Supported Calls |
30321 | @subsection List of Supported Calls | |
0ce1b118 CV |
30322 | @cindex list of supported file-i/o calls |
30323 | ||
30324 | @menu | |
30325 | * open:: | |
30326 | * close:: | |
30327 | * read:: | |
30328 | * write:: | |
30329 | * lseek:: | |
30330 | * rename:: | |
30331 | * unlink:: | |
30332 | * stat/fstat:: | |
30333 | * gettimeofday:: | |
30334 | * isatty:: | |
30335 | * system:: | |
30336 | @end menu | |
30337 | ||
30338 | @node open | |
30339 | @unnumberedsubsubsec open | |
30340 | @cindex open, file-i/o system call | |
30341 | ||
fc320d37 SL |
30342 | @table @asis |
30343 | @item Synopsis: | |
0ce1b118 | 30344 | @smallexample |
0ce1b118 CV |
30345 | int open(const char *pathname, int flags); |
30346 | int open(const char *pathname, int flags, mode_t mode); | |
0ce1b118 CV |
30347 | @end smallexample |
30348 | ||
fc320d37 SL |
30349 | @item Request: |
30350 | @samp{Fopen,@var{pathptr}/@var{len},@var{flags},@var{mode}} | |
30351 | ||
0ce1b118 | 30352 | @noindent |
fc320d37 | 30353 | @var{flags} is the bitwise @code{OR} of the following values: |
0ce1b118 CV |
30354 | |
30355 | @table @code | |
b383017d | 30356 | @item O_CREAT |
0ce1b118 CV |
30357 | If the file does not exist it will be created. The host |
30358 | rules apply as far as file ownership and time stamps | |
30359 | are concerned. | |
30360 | ||
b383017d | 30361 | @item O_EXCL |
fc320d37 | 30362 | When used with @code{O_CREAT}, if the file already exists it is |
0ce1b118 CV |
30363 | an error and open() fails. |
30364 | ||
b383017d | 30365 | @item O_TRUNC |
0ce1b118 | 30366 | If the file already exists and the open mode allows |
fc320d37 SL |
30367 | writing (@code{O_RDWR} or @code{O_WRONLY} is given) it will be |
30368 | truncated to zero length. | |
0ce1b118 | 30369 | |
b383017d | 30370 | @item O_APPEND |
0ce1b118 CV |
30371 | The file is opened in append mode. |
30372 | ||
b383017d | 30373 | @item O_RDONLY |
0ce1b118 CV |
30374 | The file is opened for reading only. |
30375 | ||
b383017d | 30376 | @item O_WRONLY |
0ce1b118 CV |
30377 | The file is opened for writing only. |
30378 | ||
b383017d | 30379 | @item O_RDWR |
0ce1b118 | 30380 | The file is opened for reading and writing. |
fc320d37 | 30381 | @end table |
0ce1b118 CV |
30382 | |
30383 | @noindent | |
fc320d37 | 30384 | Other bits are silently ignored. |
0ce1b118 | 30385 | |
0ce1b118 CV |
30386 | |
30387 | @noindent | |
fc320d37 | 30388 | @var{mode} is the bitwise @code{OR} of the following values: |
0ce1b118 CV |
30389 | |
30390 | @table @code | |
b383017d | 30391 | @item S_IRUSR |
0ce1b118 CV |
30392 | User has read permission. |
30393 | ||
b383017d | 30394 | @item S_IWUSR |
0ce1b118 CV |
30395 | User has write permission. |
30396 | ||
b383017d | 30397 | @item S_IRGRP |
0ce1b118 CV |
30398 | Group has read permission. |
30399 | ||
b383017d | 30400 | @item S_IWGRP |
0ce1b118 CV |
30401 | Group has write permission. |
30402 | ||
b383017d | 30403 | @item S_IROTH |
0ce1b118 CV |
30404 | Others have read permission. |
30405 | ||
b383017d | 30406 | @item S_IWOTH |
0ce1b118 | 30407 | Others have write permission. |
fc320d37 | 30408 | @end table |
0ce1b118 CV |
30409 | |
30410 | @noindent | |
fc320d37 | 30411 | Other bits are silently ignored. |
0ce1b118 | 30412 | |
0ce1b118 | 30413 | |
fc320d37 SL |
30414 | @item Return value: |
30415 | @code{open} returns the new file descriptor or -1 if an error | |
30416 | occurred. | |
0ce1b118 | 30417 | |
fc320d37 | 30418 | @item Errors: |
0ce1b118 CV |
30419 | |
30420 | @table @code | |
b383017d | 30421 | @item EEXIST |
fc320d37 | 30422 | @var{pathname} already exists and @code{O_CREAT} and @code{O_EXCL} were used. |
0ce1b118 | 30423 | |
b383017d | 30424 | @item EISDIR |
fc320d37 | 30425 | @var{pathname} refers to a directory. |
0ce1b118 | 30426 | |
b383017d | 30427 | @item EACCES |
0ce1b118 CV |
30428 | The requested access is not allowed. |
30429 | ||
30430 | @item ENAMETOOLONG | |
fc320d37 | 30431 | @var{pathname} was too long. |
0ce1b118 | 30432 | |
b383017d | 30433 | @item ENOENT |
fc320d37 | 30434 | A directory component in @var{pathname} does not exist. |
0ce1b118 | 30435 | |
b383017d | 30436 | @item ENODEV |
fc320d37 | 30437 | @var{pathname} refers to a device, pipe, named pipe or socket. |
0ce1b118 | 30438 | |
b383017d | 30439 | @item EROFS |
fc320d37 | 30440 | @var{pathname} refers to a file on a read-only filesystem and |
0ce1b118 CV |
30441 | write access was requested. |
30442 | ||
b383017d | 30443 | @item EFAULT |
fc320d37 | 30444 | @var{pathname} is an invalid pointer value. |
0ce1b118 | 30445 | |
b383017d | 30446 | @item ENOSPC |
0ce1b118 CV |
30447 | No space on device to create the file. |
30448 | ||
b383017d | 30449 | @item EMFILE |
0ce1b118 CV |
30450 | The process already has the maximum number of files open. |
30451 | ||
b383017d | 30452 | @item ENFILE |
0ce1b118 CV |
30453 | The limit on the total number of files open on the system |
30454 | has been reached. | |
30455 | ||
b383017d | 30456 | @item EINTR |
0ce1b118 CV |
30457 | The call was interrupted by the user. |
30458 | @end table | |
30459 | ||
fc320d37 SL |
30460 | @end table |
30461 | ||
0ce1b118 CV |
30462 | @node close |
30463 | @unnumberedsubsubsec close | |
30464 | @cindex close, file-i/o system call | |
30465 | ||
fc320d37 SL |
30466 | @table @asis |
30467 | @item Synopsis: | |
0ce1b118 | 30468 | @smallexample |
0ce1b118 | 30469 | int close(int fd); |
fc320d37 | 30470 | @end smallexample |
0ce1b118 | 30471 | |
fc320d37 SL |
30472 | @item Request: |
30473 | @samp{Fclose,@var{fd}} | |
0ce1b118 | 30474 | |
fc320d37 SL |
30475 | @item Return value: |
30476 | @code{close} returns zero on success, or -1 if an error occurred. | |
0ce1b118 | 30477 | |
fc320d37 | 30478 | @item Errors: |
0ce1b118 CV |
30479 | |
30480 | @table @code | |
b383017d | 30481 | @item EBADF |
fc320d37 | 30482 | @var{fd} isn't a valid open file descriptor. |
0ce1b118 | 30483 | |
b383017d | 30484 | @item EINTR |
0ce1b118 CV |
30485 | The call was interrupted by the user. |
30486 | @end table | |
30487 | ||
fc320d37 SL |
30488 | @end table |
30489 | ||
0ce1b118 CV |
30490 | @node read |
30491 | @unnumberedsubsubsec read | |
30492 | @cindex read, file-i/o system call | |
30493 | ||
fc320d37 SL |
30494 | @table @asis |
30495 | @item Synopsis: | |
0ce1b118 | 30496 | @smallexample |
0ce1b118 | 30497 | int read(int fd, void *buf, unsigned int count); |
fc320d37 | 30498 | @end smallexample |
0ce1b118 | 30499 | |
fc320d37 SL |
30500 | @item Request: |
30501 | @samp{Fread,@var{fd},@var{bufptr},@var{count}} | |
0ce1b118 | 30502 | |
fc320d37 | 30503 | @item Return value: |
0ce1b118 CV |
30504 | On success, the number of bytes read is returned. |
30505 | Zero indicates end of file. If count is zero, read | |
b383017d | 30506 | returns zero as well. On error, -1 is returned. |
0ce1b118 | 30507 | |
fc320d37 | 30508 | @item Errors: |
0ce1b118 CV |
30509 | |
30510 | @table @code | |
b383017d | 30511 | @item EBADF |
fc320d37 | 30512 | @var{fd} is not a valid file descriptor or is not open for |
0ce1b118 CV |
30513 | reading. |
30514 | ||
b383017d | 30515 | @item EFAULT |
fc320d37 | 30516 | @var{bufptr} is an invalid pointer value. |
0ce1b118 | 30517 | |
b383017d | 30518 | @item EINTR |
0ce1b118 CV |
30519 | The call was interrupted by the user. |
30520 | @end table | |
30521 | ||
fc320d37 SL |
30522 | @end table |
30523 | ||
0ce1b118 CV |
30524 | @node write |
30525 | @unnumberedsubsubsec write | |
30526 | @cindex write, file-i/o system call | |
30527 | ||
fc320d37 SL |
30528 | @table @asis |
30529 | @item Synopsis: | |
0ce1b118 | 30530 | @smallexample |
0ce1b118 | 30531 | int write(int fd, const void *buf, unsigned int count); |
fc320d37 | 30532 | @end smallexample |
0ce1b118 | 30533 | |
fc320d37 SL |
30534 | @item Request: |
30535 | @samp{Fwrite,@var{fd},@var{bufptr},@var{count}} | |
0ce1b118 | 30536 | |
fc320d37 | 30537 | @item Return value: |
0ce1b118 CV |
30538 | On success, the number of bytes written are returned. |
30539 | Zero indicates nothing was written. On error, -1 | |
30540 | is returned. | |
30541 | ||
fc320d37 | 30542 | @item Errors: |
0ce1b118 CV |
30543 | |
30544 | @table @code | |
b383017d | 30545 | @item EBADF |
fc320d37 | 30546 | @var{fd} is not a valid file descriptor or is not open for |
0ce1b118 CV |
30547 | writing. |
30548 | ||
b383017d | 30549 | @item EFAULT |
fc320d37 | 30550 | @var{bufptr} is an invalid pointer value. |
0ce1b118 | 30551 | |
b383017d | 30552 | @item EFBIG |
0ce1b118 | 30553 | An attempt was made to write a file that exceeds the |
db2e3e2e | 30554 | host-specific maximum file size allowed. |
0ce1b118 | 30555 | |
b383017d | 30556 | @item ENOSPC |
0ce1b118 CV |
30557 | No space on device to write the data. |
30558 | ||
b383017d | 30559 | @item EINTR |
0ce1b118 CV |
30560 | The call was interrupted by the user. |
30561 | @end table | |
30562 | ||
fc320d37 SL |
30563 | @end table |
30564 | ||
0ce1b118 CV |
30565 | @node lseek |
30566 | @unnumberedsubsubsec lseek | |
30567 | @cindex lseek, file-i/o system call | |
30568 | ||
fc320d37 SL |
30569 | @table @asis |
30570 | @item Synopsis: | |
0ce1b118 | 30571 | @smallexample |
0ce1b118 | 30572 | long lseek (int fd, long offset, int flag); |
0ce1b118 CV |
30573 | @end smallexample |
30574 | ||
fc320d37 SL |
30575 | @item Request: |
30576 | @samp{Flseek,@var{fd},@var{offset},@var{flag}} | |
30577 | ||
30578 | @var{flag} is one of: | |
0ce1b118 CV |
30579 | |
30580 | @table @code | |
b383017d | 30581 | @item SEEK_SET |
fc320d37 | 30582 | The offset is set to @var{offset} bytes. |
0ce1b118 | 30583 | |
b383017d | 30584 | @item SEEK_CUR |
fc320d37 | 30585 | The offset is set to its current location plus @var{offset} |
0ce1b118 CV |
30586 | bytes. |
30587 | ||
b383017d | 30588 | @item SEEK_END |
fc320d37 | 30589 | The offset is set to the size of the file plus @var{offset} |
0ce1b118 CV |
30590 | bytes. |
30591 | @end table | |
30592 | ||
fc320d37 | 30593 | @item Return value: |
0ce1b118 CV |
30594 | On success, the resulting unsigned offset in bytes from |
30595 | the beginning of the file is returned. Otherwise, a | |
30596 | value of -1 is returned. | |
30597 | ||
fc320d37 | 30598 | @item Errors: |
0ce1b118 CV |
30599 | |
30600 | @table @code | |
b383017d | 30601 | @item EBADF |
fc320d37 | 30602 | @var{fd} is not a valid open file descriptor. |
0ce1b118 | 30603 | |
b383017d | 30604 | @item ESPIPE |
fc320d37 | 30605 | @var{fd} is associated with the @value{GDBN} console. |
0ce1b118 | 30606 | |
b383017d | 30607 | @item EINVAL |
fc320d37 | 30608 | @var{flag} is not a proper value. |
0ce1b118 | 30609 | |
b383017d | 30610 | @item EINTR |
0ce1b118 CV |
30611 | The call was interrupted by the user. |
30612 | @end table | |
30613 | ||
fc320d37 SL |
30614 | @end table |
30615 | ||
0ce1b118 CV |
30616 | @node rename |
30617 | @unnumberedsubsubsec rename | |
30618 | @cindex rename, file-i/o system call | |
30619 | ||
fc320d37 SL |
30620 | @table @asis |
30621 | @item Synopsis: | |
0ce1b118 | 30622 | @smallexample |
0ce1b118 | 30623 | int rename(const char *oldpath, const char *newpath); |
fc320d37 | 30624 | @end smallexample |
0ce1b118 | 30625 | |
fc320d37 SL |
30626 | @item Request: |
30627 | @samp{Frename,@var{oldpathptr}/@var{len},@var{newpathptr}/@var{len}} | |
0ce1b118 | 30628 | |
fc320d37 | 30629 | @item Return value: |
0ce1b118 CV |
30630 | On success, zero is returned. On error, -1 is returned. |
30631 | ||
fc320d37 | 30632 | @item Errors: |
0ce1b118 CV |
30633 | |
30634 | @table @code | |
b383017d | 30635 | @item EISDIR |
fc320d37 | 30636 | @var{newpath} is an existing directory, but @var{oldpath} is not a |
0ce1b118 CV |
30637 | directory. |
30638 | ||
b383017d | 30639 | @item EEXIST |
fc320d37 | 30640 | @var{newpath} is a non-empty directory. |
0ce1b118 | 30641 | |
b383017d | 30642 | @item EBUSY |
fc320d37 | 30643 | @var{oldpath} or @var{newpath} is a directory that is in use by some |
0ce1b118 CV |
30644 | process. |
30645 | ||
b383017d | 30646 | @item EINVAL |
0ce1b118 CV |
30647 | An attempt was made to make a directory a subdirectory |
30648 | of itself. | |
30649 | ||
b383017d | 30650 | @item ENOTDIR |
fc320d37 SL |
30651 | A component used as a directory in @var{oldpath} or new |
30652 | path is not a directory. Or @var{oldpath} is a directory | |
30653 | and @var{newpath} exists but is not a directory. | |
0ce1b118 | 30654 | |
b383017d | 30655 | @item EFAULT |
fc320d37 | 30656 | @var{oldpathptr} or @var{newpathptr} are invalid pointer values. |
0ce1b118 | 30657 | |
b383017d | 30658 | @item EACCES |
0ce1b118 CV |
30659 | No access to the file or the path of the file. |
30660 | ||
30661 | @item ENAMETOOLONG | |
b383017d | 30662 | |
fc320d37 | 30663 | @var{oldpath} or @var{newpath} was too long. |
0ce1b118 | 30664 | |
b383017d | 30665 | @item ENOENT |
fc320d37 | 30666 | A directory component in @var{oldpath} or @var{newpath} does not exist. |
0ce1b118 | 30667 | |
b383017d | 30668 | @item EROFS |
0ce1b118 CV |
30669 | The file is on a read-only filesystem. |
30670 | ||
b383017d | 30671 | @item ENOSPC |
0ce1b118 CV |
30672 | The device containing the file has no room for the new |
30673 | directory entry. | |
30674 | ||
b383017d | 30675 | @item EINTR |
0ce1b118 CV |
30676 | The call was interrupted by the user. |
30677 | @end table | |
30678 | ||
fc320d37 SL |
30679 | @end table |
30680 | ||
0ce1b118 CV |
30681 | @node unlink |
30682 | @unnumberedsubsubsec unlink | |
30683 | @cindex unlink, file-i/o system call | |
30684 | ||
fc320d37 SL |
30685 | @table @asis |
30686 | @item Synopsis: | |
0ce1b118 | 30687 | @smallexample |
0ce1b118 | 30688 | int unlink(const char *pathname); |
fc320d37 | 30689 | @end smallexample |
0ce1b118 | 30690 | |
fc320d37 SL |
30691 | @item Request: |
30692 | @samp{Funlink,@var{pathnameptr}/@var{len}} | |
0ce1b118 | 30693 | |
fc320d37 | 30694 | @item Return value: |
0ce1b118 CV |
30695 | On success, zero is returned. On error, -1 is returned. |
30696 | ||
fc320d37 | 30697 | @item Errors: |
0ce1b118 CV |
30698 | |
30699 | @table @code | |
b383017d | 30700 | @item EACCES |
0ce1b118 CV |
30701 | No access to the file or the path of the file. |
30702 | ||
b383017d | 30703 | @item EPERM |
0ce1b118 CV |
30704 | The system does not allow unlinking of directories. |
30705 | ||
b383017d | 30706 | @item EBUSY |
fc320d37 | 30707 | The file @var{pathname} cannot be unlinked because it's |
0ce1b118 CV |
30708 | being used by another process. |
30709 | ||
b383017d | 30710 | @item EFAULT |
fc320d37 | 30711 | @var{pathnameptr} is an invalid pointer value. |
0ce1b118 CV |
30712 | |
30713 | @item ENAMETOOLONG | |
fc320d37 | 30714 | @var{pathname} was too long. |
0ce1b118 | 30715 | |
b383017d | 30716 | @item ENOENT |
fc320d37 | 30717 | A directory component in @var{pathname} does not exist. |
0ce1b118 | 30718 | |
b383017d | 30719 | @item ENOTDIR |
0ce1b118 CV |
30720 | A component of the path is not a directory. |
30721 | ||
b383017d | 30722 | @item EROFS |
0ce1b118 CV |
30723 | The file is on a read-only filesystem. |
30724 | ||
b383017d | 30725 | @item EINTR |
0ce1b118 CV |
30726 | The call was interrupted by the user. |
30727 | @end table | |
30728 | ||
fc320d37 SL |
30729 | @end table |
30730 | ||
0ce1b118 CV |
30731 | @node stat/fstat |
30732 | @unnumberedsubsubsec stat/fstat | |
30733 | @cindex fstat, file-i/o system call | |
30734 | @cindex stat, file-i/o system call | |
30735 | ||
fc320d37 SL |
30736 | @table @asis |
30737 | @item Synopsis: | |
0ce1b118 | 30738 | @smallexample |
0ce1b118 CV |
30739 | int stat(const char *pathname, struct stat *buf); |
30740 | int fstat(int fd, struct stat *buf); | |
fc320d37 | 30741 | @end smallexample |
0ce1b118 | 30742 | |
fc320d37 SL |
30743 | @item Request: |
30744 | @samp{Fstat,@var{pathnameptr}/@var{len},@var{bufptr}}@* | |
30745 | @samp{Ffstat,@var{fd},@var{bufptr}} | |
0ce1b118 | 30746 | |
fc320d37 | 30747 | @item Return value: |
0ce1b118 CV |
30748 | On success, zero is returned. On error, -1 is returned. |
30749 | ||
fc320d37 | 30750 | @item Errors: |
0ce1b118 CV |
30751 | |
30752 | @table @code | |
b383017d | 30753 | @item EBADF |
fc320d37 | 30754 | @var{fd} is not a valid open file. |
0ce1b118 | 30755 | |
b383017d | 30756 | @item ENOENT |
fc320d37 | 30757 | A directory component in @var{pathname} does not exist or the |
0ce1b118 CV |
30758 | path is an empty string. |
30759 | ||
b383017d | 30760 | @item ENOTDIR |
0ce1b118 CV |
30761 | A component of the path is not a directory. |
30762 | ||
b383017d | 30763 | @item EFAULT |
fc320d37 | 30764 | @var{pathnameptr} is an invalid pointer value. |
0ce1b118 | 30765 | |
b383017d | 30766 | @item EACCES |
0ce1b118 CV |
30767 | No access to the file or the path of the file. |
30768 | ||
30769 | @item ENAMETOOLONG | |
fc320d37 | 30770 | @var{pathname} was too long. |
0ce1b118 | 30771 | |
b383017d | 30772 | @item EINTR |
0ce1b118 CV |
30773 | The call was interrupted by the user. |
30774 | @end table | |
30775 | ||
fc320d37 SL |
30776 | @end table |
30777 | ||
0ce1b118 CV |
30778 | @node gettimeofday |
30779 | @unnumberedsubsubsec gettimeofday | |
30780 | @cindex gettimeofday, file-i/o system call | |
30781 | ||
fc320d37 SL |
30782 | @table @asis |
30783 | @item Synopsis: | |
0ce1b118 | 30784 | @smallexample |
0ce1b118 | 30785 | int gettimeofday(struct timeval *tv, void *tz); |
fc320d37 | 30786 | @end smallexample |
0ce1b118 | 30787 | |
fc320d37 SL |
30788 | @item Request: |
30789 | @samp{Fgettimeofday,@var{tvptr},@var{tzptr}} | |
0ce1b118 | 30790 | |
fc320d37 | 30791 | @item Return value: |
0ce1b118 CV |
30792 | On success, 0 is returned, -1 otherwise. |
30793 | ||
fc320d37 | 30794 | @item Errors: |
0ce1b118 CV |
30795 | |
30796 | @table @code | |
b383017d | 30797 | @item EINVAL |
fc320d37 | 30798 | @var{tz} is a non-NULL pointer. |
0ce1b118 | 30799 | |
b383017d | 30800 | @item EFAULT |
fc320d37 SL |
30801 | @var{tvptr} and/or @var{tzptr} is an invalid pointer value. |
30802 | @end table | |
30803 | ||
0ce1b118 CV |
30804 | @end table |
30805 | ||
30806 | @node isatty | |
30807 | @unnumberedsubsubsec isatty | |
30808 | @cindex isatty, file-i/o system call | |
30809 | ||
fc320d37 SL |
30810 | @table @asis |
30811 | @item Synopsis: | |
0ce1b118 | 30812 | @smallexample |
0ce1b118 | 30813 | int isatty(int fd); |
fc320d37 | 30814 | @end smallexample |
0ce1b118 | 30815 | |
fc320d37 SL |
30816 | @item Request: |
30817 | @samp{Fisatty,@var{fd}} | |
0ce1b118 | 30818 | |
fc320d37 SL |
30819 | @item Return value: |
30820 | Returns 1 if @var{fd} refers to the @value{GDBN} console, 0 otherwise. | |
0ce1b118 | 30821 | |
fc320d37 | 30822 | @item Errors: |
0ce1b118 CV |
30823 | |
30824 | @table @code | |
b383017d | 30825 | @item EINTR |
0ce1b118 CV |
30826 | The call was interrupted by the user. |
30827 | @end table | |
30828 | ||
fc320d37 SL |
30829 | @end table |
30830 | ||
30831 | Note that the @code{isatty} call is treated as a special case: it returns | |
30832 | 1 to the target if the file descriptor is attached | |
30833 | to the @value{GDBN} console, 0 otherwise. Implementing through system calls | |
30834 | would require implementing @code{ioctl} and would be more complex than | |
30835 | needed. | |
30836 | ||
30837 | ||
0ce1b118 CV |
30838 | @node system |
30839 | @unnumberedsubsubsec system | |
30840 | @cindex system, file-i/o system call | |
30841 | ||
fc320d37 SL |
30842 | @table @asis |
30843 | @item Synopsis: | |
0ce1b118 | 30844 | @smallexample |
0ce1b118 | 30845 | int system(const char *command); |
fc320d37 | 30846 | @end smallexample |
0ce1b118 | 30847 | |
fc320d37 SL |
30848 | @item Request: |
30849 | @samp{Fsystem,@var{commandptr}/@var{len}} | |
0ce1b118 | 30850 | |
fc320d37 | 30851 | @item Return value: |
5600ea19 NS |
30852 | If @var{len} is zero, the return value indicates whether a shell is |
30853 | available. A zero return value indicates a shell is not available. | |
30854 | For non-zero @var{len}, the value returned is -1 on error and the | |
30855 | return status of the command otherwise. Only the exit status of the | |
30856 | command is returned, which is extracted from the host's @code{system} | |
30857 | return value by calling @code{WEXITSTATUS(retval)}. In case | |
30858 | @file{/bin/sh} could not be executed, 127 is returned. | |
0ce1b118 | 30859 | |
fc320d37 | 30860 | @item Errors: |
0ce1b118 CV |
30861 | |
30862 | @table @code | |
b383017d | 30863 | @item EINTR |
0ce1b118 CV |
30864 | The call was interrupted by the user. |
30865 | @end table | |
30866 | ||
fc320d37 SL |
30867 | @end table |
30868 | ||
30869 | @value{GDBN} takes over the full task of calling the necessary host calls | |
30870 | to perform the @code{system} call. The return value of @code{system} on | |
30871 | the host is simplified before it's returned | |
30872 | to the target. Any termination signal information from the child process | |
30873 | is discarded, and the return value consists | |
30874 | entirely of the exit status of the called command. | |
30875 | ||
30876 | Due to security concerns, the @code{system} call is by default refused | |
30877 | by @value{GDBN}. The user has to allow this call explicitly with the | |
30878 | @code{set remote system-call-allowed 1} command. | |
30879 | ||
30880 | @table @code | |
30881 | @item set remote system-call-allowed | |
30882 | @kindex set remote system-call-allowed | |
30883 | Control whether to allow the @code{system} calls in the File I/O | |
30884 | protocol for the remote target. The default is zero (disabled). | |
30885 | ||
30886 | @item show remote system-call-allowed | |
30887 | @kindex show remote system-call-allowed | |
30888 | Show whether the @code{system} calls are allowed in the File I/O | |
30889 | protocol. | |
30890 | @end table | |
30891 | ||
db2e3e2e BW |
30892 | @node Protocol-specific Representation of Datatypes |
30893 | @subsection Protocol-specific Representation of Datatypes | |
30894 | @cindex protocol-specific representation of datatypes, in file-i/o protocol | |
0ce1b118 CV |
30895 | |
30896 | @menu | |
79a6e687 BW |
30897 | * Integral Datatypes:: |
30898 | * Pointer Values:: | |
30899 | * Memory Transfer:: | |
0ce1b118 CV |
30900 | * struct stat:: |
30901 | * struct timeval:: | |
30902 | @end menu | |
30903 | ||
79a6e687 BW |
30904 | @node Integral Datatypes |
30905 | @unnumberedsubsubsec Integral Datatypes | |
0ce1b118 CV |
30906 | @cindex integral datatypes, in file-i/o protocol |
30907 | ||
fc320d37 SL |
30908 | The integral datatypes used in the system calls are @code{int}, |
30909 | @code{unsigned int}, @code{long}, @code{unsigned long}, | |
30910 | @code{mode_t}, and @code{time_t}. | |
0ce1b118 | 30911 | |
fc320d37 | 30912 | @code{int}, @code{unsigned int}, @code{mode_t} and @code{time_t} are |
0ce1b118 CV |
30913 | implemented as 32 bit values in this protocol. |
30914 | ||
fc320d37 | 30915 | @code{long} and @code{unsigned long} are implemented as 64 bit types. |
b383017d | 30916 | |
0ce1b118 CV |
30917 | @xref{Limits}, for corresponding MIN and MAX values (similar to those |
30918 | in @file{limits.h}) to allow range checking on host and target. | |
30919 | ||
30920 | @code{time_t} datatypes are defined as seconds since the Epoch. | |
30921 | ||
30922 | All integral datatypes transferred as part of a memory read or write of a | |
30923 | structured datatype e.g.@: a @code{struct stat} have to be given in big endian | |
30924 | byte order. | |
30925 | ||
79a6e687 BW |
30926 | @node Pointer Values |
30927 | @unnumberedsubsubsec Pointer Values | |
0ce1b118 CV |
30928 | @cindex pointer values, in file-i/o protocol |
30929 | ||
30930 | Pointers to target data are transmitted as they are. An exception | |
30931 | is made for pointers to buffers for which the length isn't | |
30932 | transmitted as part of the function call, namely strings. Strings | |
30933 | are transmitted as a pointer/length pair, both as hex values, e.g.@: | |
30934 | ||
30935 | @smallexample | |
30936 | @code{1aaf/12} | |
30937 | @end smallexample | |
30938 | ||
30939 | @noindent | |
30940 | which is a pointer to data of length 18 bytes at position 0x1aaf. | |
30941 | The length is defined as the full string length in bytes, including | |
fc320d37 SL |
30942 | the trailing null byte. For example, the string @code{"hello world"} |
30943 | at address 0x123456 is transmitted as | |
0ce1b118 CV |
30944 | |
30945 | @smallexample | |
fc320d37 | 30946 | @code{123456/d} |
0ce1b118 CV |
30947 | @end smallexample |
30948 | ||
79a6e687 BW |
30949 | @node Memory Transfer |
30950 | @unnumberedsubsubsec Memory Transfer | |
fc320d37 SL |
30951 | @cindex memory transfer, in file-i/o protocol |
30952 | ||
30953 | Structured data which is transferred using a memory read or write (for | |
db2e3e2e | 30954 | example, a @code{struct stat}) is expected to be in a protocol-specific format |
fc320d37 SL |
30955 | with all scalar multibyte datatypes being big endian. Translation to |
30956 | this representation needs to be done both by the target before the @code{F} | |
30957 | packet is sent, and by @value{GDBN} before | |
30958 | it transfers memory to the target. Transferred pointers to structured | |
30959 | data should point to the already-coerced data at any time. | |
0ce1b118 | 30960 | |
0ce1b118 CV |
30961 | |
30962 | @node struct stat | |
30963 | @unnumberedsubsubsec struct stat | |
30964 | @cindex struct stat, in file-i/o protocol | |
30965 | ||
fc320d37 SL |
30966 | The buffer of type @code{struct stat} used by the target and @value{GDBN} |
30967 | is defined as follows: | |
0ce1b118 CV |
30968 | |
30969 | @smallexample | |
30970 | struct stat @{ | |
30971 | unsigned int st_dev; /* device */ | |
30972 | unsigned int st_ino; /* inode */ | |
30973 | mode_t st_mode; /* protection */ | |
30974 | unsigned int st_nlink; /* number of hard links */ | |
30975 | unsigned int st_uid; /* user ID of owner */ | |
30976 | unsigned int st_gid; /* group ID of owner */ | |
30977 | unsigned int st_rdev; /* device type (if inode device) */ | |
30978 | unsigned long st_size; /* total size, in bytes */ | |
30979 | unsigned long st_blksize; /* blocksize for filesystem I/O */ | |
30980 | unsigned long st_blocks; /* number of blocks allocated */ | |
30981 | time_t st_atime; /* time of last access */ | |
30982 | time_t st_mtime; /* time of last modification */ | |
30983 | time_t st_ctime; /* time of last change */ | |
30984 | @}; | |
30985 | @end smallexample | |
30986 | ||
fc320d37 | 30987 | The integral datatypes conform to the definitions given in the |
79a6e687 | 30988 | appropriate section (see @ref{Integral Datatypes}, for details) so this |
0ce1b118 CV |
30989 | structure is of size 64 bytes. |
30990 | ||
30991 | The values of several fields have a restricted meaning and/or | |
30992 | range of values. | |
30993 | ||
fc320d37 | 30994 | @table @code |
0ce1b118 | 30995 | |
fc320d37 SL |
30996 | @item st_dev |
30997 | A value of 0 represents a file, 1 the console. | |
0ce1b118 | 30998 | |
fc320d37 SL |
30999 | @item st_ino |
31000 | No valid meaning for the target. Transmitted unchanged. | |
0ce1b118 | 31001 | |
fc320d37 SL |
31002 | @item st_mode |
31003 | Valid mode bits are described in @ref{Constants}. Any other | |
31004 | bits have currently no meaning for the target. | |
0ce1b118 | 31005 | |
fc320d37 SL |
31006 | @item st_uid |
31007 | @itemx st_gid | |
31008 | @itemx st_rdev | |
31009 | No valid meaning for the target. Transmitted unchanged. | |
0ce1b118 | 31010 | |
fc320d37 SL |
31011 | @item st_atime |
31012 | @itemx st_mtime | |
31013 | @itemx st_ctime | |
31014 | These values have a host and file system dependent | |
31015 | accuracy. Especially on Windows hosts, the file system may not | |
31016 | support exact timing values. | |
31017 | @end table | |
0ce1b118 | 31018 | |
fc320d37 SL |
31019 | The target gets a @code{struct stat} of the above representation and is |
31020 | responsible for coercing it to the target representation before | |
0ce1b118 CV |
31021 | continuing. |
31022 | ||
fc320d37 SL |
31023 | Note that due to size differences between the host, target, and protocol |
31024 | representations of @code{struct stat} members, these members could eventually | |
0ce1b118 CV |
31025 | get truncated on the target. |
31026 | ||
31027 | @node struct timeval | |
31028 | @unnumberedsubsubsec struct timeval | |
31029 | @cindex struct timeval, in file-i/o protocol | |
31030 | ||
fc320d37 | 31031 | The buffer of type @code{struct timeval} used by the File-I/O protocol |
0ce1b118 CV |
31032 | is defined as follows: |
31033 | ||
31034 | @smallexample | |
b383017d | 31035 | struct timeval @{ |
0ce1b118 CV |
31036 | time_t tv_sec; /* second */ |
31037 | long tv_usec; /* microsecond */ | |
31038 | @}; | |
31039 | @end smallexample | |
31040 | ||
fc320d37 | 31041 | The integral datatypes conform to the definitions given in the |
79a6e687 | 31042 | appropriate section (see @ref{Integral Datatypes}, for details) so this |
0ce1b118 CV |
31043 | structure is of size 8 bytes. |
31044 | ||
31045 | @node Constants | |
31046 | @subsection Constants | |
31047 | @cindex constants, in file-i/o protocol | |
31048 | ||
31049 | The following values are used for the constants inside of the | |
fc320d37 | 31050 | protocol. @value{GDBN} and target are responsible for translating these |
0ce1b118 CV |
31051 | values before and after the call as needed. |
31052 | ||
31053 | @menu | |
79a6e687 BW |
31054 | * Open Flags:: |
31055 | * mode_t Values:: | |
31056 | * Errno Values:: | |
31057 | * Lseek Flags:: | |
0ce1b118 CV |
31058 | * Limits:: |
31059 | @end menu | |
31060 | ||
79a6e687 BW |
31061 | @node Open Flags |
31062 | @unnumberedsubsubsec Open Flags | |
0ce1b118 CV |
31063 | @cindex open flags, in file-i/o protocol |
31064 | ||
31065 | All values are given in hexadecimal representation. | |
31066 | ||
31067 | @smallexample | |
31068 | O_RDONLY 0x0 | |
31069 | O_WRONLY 0x1 | |
31070 | O_RDWR 0x2 | |
31071 | O_APPEND 0x8 | |
31072 | O_CREAT 0x200 | |
31073 | O_TRUNC 0x400 | |
31074 | O_EXCL 0x800 | |
31075 | @end smallexample | |
31076 | ||
79a6e687 BW |
31077 | @node mode_t Values |
31078 | @unnumberedsubsubsec mode_t Values | |
0ce1b118 CV |
31079 | @cindex mode_t values, in file-i/o protocol |
31080 | ||
31081 | All values are given in octal representation. | |
31082 | ||
31083 | @smallexample | |
31084 | S_IFREG 0100000 | |
31085 | S_IFDIR 040000 | |
31086 | S_IRUSR 0400 | |
31087 | S_IWUSR 0200 | |
31088 | S_IXUSR 0100 | |
31089 | S_IRGRP 040 | |
31090 | S_IWGRP 020 | |
31091 | S_IXGRP 010 | |
31092 | S_IROTH 04 | |
31093 | S_IWOTH 02 | |
31094 | S_IXOTH 01 | |
31095 | @end smallexample | |
31096 | ||
79a6e687 BW |
31097 | @node Errno Values |
31098 | @unnumberedsubsubsec Errno Values | |
0ce1b118 CV |
31099 | @cindex errno values, in file-i/o protocol |
31100 | ||
31101 | All values are given in decimal representation. | |
31102 | ||
31103 | @smallexample | |
31104 | EPERM 1 | |
31105 | ENOENT 2 | |
31106 | EINTR 4 | |
31107 | EBADF 9 | |
31108 | EACCES 13 | |
31109 | EFAULT 14 | |
31110 | EBUSY 16 | |
31111 | EEXIST 17 | |
31112 | ENODEV 19 | |
31113 | ENOTDIR 20 | |
31114 | EISDIR 21 | |
31115 | EINVAL 22 | |
31116 | ENFILE 23 | |
31117 | EMFILE 24 | |
31118 | EFBIG 27 | |
31119 | ENOSPC 28 | |
31120 | ESPIPE 29 | |
31121 | EROFS 30 | |
31122 | ENAMETOOLONG 91 | |
31123 | EUNKNOWN 9999 | |
31124 | @end smallexample | |
31125 | ||
fc320d37 | 31126 | @code{EUNKNOWN} is used as a fallback error value if a host system returns |
0ce1b118 CV |
31127 | any error value not in the list of supported error numbers. |
31128 | ||
79a6e687 BW |
31129 | @node Lseek Flags |
31130 | @unnumberedsubsubsec Lseek Flags | |
0ce1b118 CV |
31131 | @cindex lseek flags, in file-i/o protocol |
31132 | ||
31133 | @smallexample | |
31134 | SEEK_SET 0 | |
31135 | SEEK_CUR 1 | |
31136 | SEEK_END 2 | |
31137 | @end smallexample | |
31138 | ||
31139 | @node Limits | |
31140 | @unnumberedsubsubsec Limits | |
31141 | @cindex limits, in file-i/o protocol | |
31142 | ||
31143 | All values are given in decimal representation. | |
31144 | ||
31145 | @smallexample | |
31146 | INT_MIN -2147483648 | |
31147 | INT_MAX 2147483647 | |
31148 | UINT_MAX 4294967295 | |
31149 | LONG_MIN -9223372036854775808 | |
31150 | LONG_MAX 9223372036854775807 | |
31151 | ULONG_MAX 18446744073709551615 | |
31152 | @end smallexample | |
31153 | ||
31154 | @node File-I/O Examples | |
31155 | @subsection File-I/O Examples | |
31156 | @cindex file-i/o examples | |
31157 | ||
31158 | Example sequence of a write call, file descriptor 3, buffer is at target | |
31159 | address 0x1234, 6 bytes should be written: | |
31160 | ||
31161 | @smallexample | |
31162 | <- @code{Fwrite,3,1234,6} | |
31163 | @emph{request memory read from target} | |
31164 | -> @code{m1234,6} | |
31165 | <- XXXXXX | |
31166 | @emph{return "6 bytes written"} | |
31167 | -> @code{F6} | |
31168 | @end smallexample | |
31169 | ||
31170 | Example sequence of a read call, file descriptor 3, buffer is at target | |
31171 | address 0x1234, 6 bytes should be read: | |
31172 | ||
31173 | @smallexample | |
31174 | <- @code{Fread,3,1234,6} | |
31175 | @emph{request memory write to target} | |
31176 | -> @code{X1234,6:XXXXXX} | |
31177 | @emph{return "6 bytes read"} | |
31178 | -> @code{F6} | |
31179 | @end smallexample | |
31180 | ||
31181 | Example sequence of a read call, call fails on the host due to invalid | |
fc320d37 | 31182 | file descriptor (@code{EBADF}): |
0ce1b118 CV |
31183 | |
31184 | @smallexample | |
31185 | <- @code{Fread,3,1234,6} | |
31186 | -> @code{F-1,9} | |
31187 | @end smallexample | |
31188 | ||
c8aa23ab | 31189 | Example sequence of a read call, user presses @kbd{Ctrl-c} before syscall on |
0ce1b118 CV |
31190 | host is called: |
31191 | ||
31192 | @smallexample | |
31193 | <- @code{Fread,3,1234,6} | |
31194 | -> @code{F-1,4,C} | |
31195 | <- @code{T02} | |
31196 | @end smallexample | |
31197 | ||
c8aa23ab | 31198 | Example sequence of a read call, user presses @kbd{Ctrl-c} after syscall on |
0ce1b118 CV |
31199 | host is called: |
31200 | ||
31201 | @smallexample | |
31202 | <- @code{Fread,3,1234,6} | |
31203 | -> @code{X1234,6:XXXXXX} | |
31204 | <- @code{T02} | |
31205 | @end smallexample | |
31206 | ||
cfa9d6d9 DJ |
31207 | @node Library List Format |
31208 | @section Library List Format | |
31209 | @cindex library list format, remote protocol | |
31210 | ||
31211 | On some platforms, a dynamic loader (e.g.@: @file{ld.so}) runs in the | |
31212 | same process as your application to manage libraries. In this case, | |
31213 | @value{GDBN} can use the loader's symbol table and normal memory | |
31214 | operations to maintain a list of shared libraries. On other | |
31215 | platforms, the operating system manages loaded libraries. | |
31216 | @value{GDBN} can not retrieve the list of currently loaded libraries | |
31217 | through memory operations, so it uses the @samp{qXfer:libraries:read} | |
31218 | packet (@pxref{qXfer library list read}) instead. The remote stub | |
31219 | queries the target's operating system and reports which libraries | |
31220 | are loaded. | |
31221 | ||
31222 | The @samp{qXfer:libraries:read} packet returns an XML document which | |
31223 | lists loaded libraries and their offsets. Each library has an | |
1fddbabb PA |
31224 | associated name and one or more segment or section base addresses, |
31225 | which report where the library was loaded in memory. | |
31226 | ||
31227 | For the common case of libraries that are fully linked binaries, the | |
31228 | library should have a list of segments. If the target supports | |
31229 | dynamic linking of a relocatable object file, its library XML element | |
31230 | should instead include a list of allocated sections. The segment or | |
31231 | section bases are start addresses, not relocation offsets; they do not | |
31232 | depend on the library's link-time base addresses. | |
cfa9d6d9 | 31233 | |
9cceb671 DJ |
31234 | @value{GDBN} must be linked with the Expat library to support XML |
31235 | library lists. @xref{Expat}. | |
31236 | ||
cfa9d6d9 DJ |
31237 | A simple memory map, with one loaded library relocated by a single |
31238 | offset, looks like this: | |
31239 | ||
31240 | @smallexample | |
31241 | <library-list> | |
31242 | <library name="/lib/libc.so.6"> | |
31243 | <segment address="0x10000000"/> | |
31244 | </library> | |
31245 | </library-list> | |
31246 | @end smallexample | |
31247 | ||
1fddbabb PA |
31248 | Another simple memory map, with one loaded library with three |
31249 | allocated sections (.text, .data, .bss), looks like this: | |
31250 | ||
31251 | @smallexample | |
31252 | <library-list> | |
31253 | <library name="sharedlib.o"> | |
31254 | <section address="0x10000000"/> | |
31255 | <section address="0x20000000"/> | |
31256 | <section address="0x30000000"/> | |
31257 | </library> | |
31258 | </library-list> | |
31259 | @end smallexample | |
31260 | ||
cfa9d6d9 DJ |
31261 | The format of a library list is described by this DTD: |
31262 | ||
31263 | @smallexample | |
31264 | <!-- library-list: Root element with versioning --> | |
31265 | <!ELEMENT library-list (library)*> | |
31266 | <!ATTLIST library-list version CDATA #FIXED "1.0"> | |
1fddbabb | 31267 | <!ELEMENT library (segment*, section*)> |
cfa9d6d9 DJ |
31268 | <!ATTLIST library name CDATA #REQUIRED> |
31269 | <!ELEMENT segment EMPTY> | |
31270 | <!ATTLIST segment address CDATA #REQUIRED> | |
1fddbabb PA |
31271 | <!ELEMENT section EMPTY> |
31272 | <!ATTLIST section address CDATA #REQUIRED> | |
cfa9d6d9 DJ |
31273 | @end smallexample |
31274 | ||
1fddbabb PA |
31275 | In addition, segments and section descriptors cannot be mixed within a |
31276 | single library element, and you must supply at least one segment or | |
31277 | section for each library. | |
31278 | ||
79a6e687 BW |
31279 | @node Memory Map Format |
31280 | @section Memory Map Format | |
68437a39 DJ |
31281 | @cindex memory map format |
31282 | ||
31283 | To be able to write into flash memory, @value{GDBN} needs to obtain a | |
31284 | memory map from the target. This section describes the format of the | |
31285 | memory map. | |
31286 | ||
31287 | The memory map is obtained using the @samp{qXfer:memory-map:read} | |
31288 | (@pxref{qXfer memory map read}) packet and is an XML document that | |
9cceb671 DJ |
31289 | lists memory regions. |
31290 | ||
31291 | @value{GDBN} must be linked with the Expat library to support XML | |
31292 | memory maps. @xref{Expat}. | |
31293 | ||
31294 | The top-level structure of the document is shown below: | |
68437a39 DJ |
31295 | |
31296 | @smallexample | |
31297 | <?xml version="1.0"?> | |
31298 | <!DOCTYPE memory-map | |
31299 | PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN" | |
31300 | "http://sourceware.org/gdb/gdb-memory-map.dtd"> | |
31301 | <memory-map> | |
31302 | region... | |
31303 | </memory-map> | |
31304 | @end smallexample | |
31305 | ||
31306 | Each region can be either: | |
31307 | ||
31308 | @itemize | |
31309 | ||
31310 | @item | |
31311 | A region of RAM starting at @var{addr} and extending for @var{length} | |
31312 | bytes from there: | |
31313 | ||
31314 | @smallexample | |
31315 | <memory type="ram" start="@var{addr}" length="@var{length}"/> | |
31316 | @end smallexample | |
31317 | ||
31318 | ||
31319 | @item | |
31320 | A region of read-only memory: | |
31321 | ||
31322 | @smallexample | |
31323 | <memory type="rom" start="@var{addr}" length="@var{length}"/> | |
31324 | @end smallexample | |
31325 | ||
31326 | ||
31327 | @item | |
31328 | A region of flash memory, with erasure blocks @var{blocksize} | |
31329 | bytes in length: | |
31330 | ||
31331 | @smallexample | |
31332 | <memory type="flash" start="@var{addr}" length="@var{length}"> | |
31333 | <property name="blocksize">@var{blocksize}</property> | |
31334 | </memory> | |
31335 | @end smallexample | |
31336 | ||
31337 | @end itemize | |
31338 | ||
31339 | Regions must not overlap. @value{GDBN} assumes that areas of memory not covered | |
31340 | by the memory map are RAM, and uses the ordinary @samp{M} and @samp{X} | |
31341 | packets to write to addresses in such ranges. | |
31342 | ||
31343 | The formal DTD for memory map format is given below: | |
31344 | ||
31345 | @smallexample | |
31346 | <!-- ................................................... --> | |
31347 | <!-- Memory Map XML DTD ................................ --> | |
31348 | <!-- File: memory-map.dtd .............................. --> | |
31349 | <!-- .................................... .............. --> | |
31350 | <!-- memory-map.dtd --> | |
31351 | <!-- memory-map: Root element with versioning --> | |
31352 | <!ELEMENT memory-map (memory | property)> | |
31353 | <!ATTLIST memory-map version CDATA #FIXED "1.0.0"> | |
31354 | <!ELEMENT memory (property)> | |
31355 | <!-- memory: Specifies a memory region, | |
31356 | and its type, or device. --> | |
31357 | <!ATTLIST memory type CDATA #REQUIRED | |
31358 | start CDATA #REQUIRED | |
31359 | length CDATA #REQUIRED | |
31360 | device CDATA #IMPLIED> | |
31361 | <!-- property: Generic attribute tag --> | |
31362 | <!ELEMENT property (#PCDATA | property)*> | |
31363 | <!ATTLIST property name CDATA #REQUIRED> | |
31364 | @end smallexample | |
31365 | ||
f418dd93 DJ |
31366 | @include agentexpr.texi |
31367 | ||
23181151 DJ |
31368 | @node Target Descriptions |
31369 | @appendix Target Descriptions | |
31370 | @cindex target descriptions | |
31371 | ||
31372 | @strong{Warning:} target descriptions are still under active development, | |
31373 | and the contents and format may change between @value{GDBN} releases. | |
31374 | The format is expected to stabilize in the future. | |
31375 | ||
31376 | One of the challenges of using @value{GDBN} to debug embedded systems | |
31377 | is that there are so many minor variants of each processor | |
31378 | architecture in use. It is common practice for vendors to start with | |
31379 | a standard processor core --- ARM, PowerPC, or MIPS, for example --- | |
31380 | and then make changes to adapt it to a particular market niche. Some | |
31381 | architectures have hundreds of variants, available from dozens of | |
31382 | vendors. This leads to a number of problems: | |
31383 | ||
31384 | @itemize @bullet | |
31385 | @item | |
31386 | With so many different customized processors, it is difficult for | |
31387 | the @value{GDBN} maintainers to keep up with the changes. | |
31388 | @item | |
31389 | Since individual variants may have short lifetimes or limited | |
31390 | audiences, it may not be worthwhile to carry information about every | |
31391 | variant in the @value{GDBN} source tree. | |
31392 | @item | |
31393 | When @value{GDBN} does support the architecture of the embedded system | |
31394 | at hand, the task of finding the correct architecture name to give the | |
31395 | @command{set architecture} command can be error-prone. | |
31396 | @end itemize | |
31397 | ||
31398 | To address these problems, the @value{GDBN} remote protocol allows a | |
31399 | target system to not only identify itself to @value{GDBN}, but to | |
31400 | actually describe its own features. This lets @value{GDBN} support | |
31401 | processor variants it has never seen before --- to the extent that the | |
31402 | descriptions are accurate, and that @value{GDBN} understands them. | |
31403 | ||
9cceb671 DJ |
31404 | @value{GDBN} must be linked with the Expat library to support XML |
31405 | target descriptions. @xref{Expat}. | |
123dc839 | 31406 | |
23181151 DJ |
31407 | @menu |
31408 | * Retrieving Descriptions:: How descriptions are fetched from a target. | |
31409 | * Target Description Format:: The contents of a target description. | |
123dc839 DJ |
31410 | * Predefined Target Types:: Standard types available for target |
31411 | descriptions. | |
31412 | * Standard Target Features:: Features @value{GDBN} knows about. | |
23181151 DJ |
31413 | @end menu |
31414 | ||
31415 | @node Retrieving Descriptions | |
31416 | @section Retrieving Descriptions | |
31417 | ||
31418 | Target descriptions can be read from the target automatically, or | |
31419 | specified by the user manually. The default behavior is to read the | |
31420 | description from the target. @value{GDBN} retrieves it via the remote | |
31421 | protocol using @samp{qXfer} requests (@pxref{General Query Packets, | |
31422 | qXfer}). The @var{annex} in the @samp{qXfer} packet will be | |
31423 | @samp{target.xml}. The contents of the @samp{target.xml} annex are an | |
31424 | XML document, of the form described in @ref{Target Description | |
31425 | Format}. | |
31426 | ||
31427 | Alternatively, you can specify a file to read for the target description. | |
31428 | If a file is set, the target will not be queried. The commands to | |
31429 | specify a file are: | |
31430 | ||
31431 | @table @code | |
31432 | @cindex set tdesc filename | |
31433 | @item set tdesc filename @var{path} | |
31434 | Read the target description from @var{path}. | |
31435 | ||
31436 | @cindex unset tdesc filename | |
31437 | @item unset tdesc filename | |
31438 | Do not read the XML target description from a file. @value{GDBN} | |
31439 | will use the description supplied by the current target. | |
31440 | ||
31441 | @cindex show tdesc filename | |
31442 | @item show tdesc filename | |
31443 | Show the filename to read for a target description, if any. | |
31444 | @end table | |
31445 | ||
31446 | ||
31447 | @node Target Description Format | |
31448 | @section Target Description Format | |
31449 | @cindex target descriptions, XML format | |
31450 | ||
31451 | A target description annex is an @uref{http://www.w3.org/XML/, XML} | |
31452 | document which complies with the Document Type Definition provided in | |
31453 | the @value{GDBN} sources in @file{gdb/features/gdb-target.dtd}. This | |
31454 | means you can use generally available tools like @command{xmllint} to | |
31455 | check that your feature descriptions are well-formed and valid. | |
31456 | However, to help people unfamiliar with XML write descriptions for | |
31457 | their targets, we also describe the grammar here. | |
31458 | ||
123dc839 DJ |
31459 | Target descriptions can identify the architecture of the remote target |
31460 | and (for some architectures) provide information about custom register | |
08d16641 PA |
31461 | sets. They can also identify the OS ABI of the remote target. |
31462 | @value{GDBN} can use this information to autoconfigure for your | |
123dc839 | 31463 | target, or to warn you if you connect to an unsupported target. |
23181151 DJ |
31464 | |
31465 | Here is a simple target description: | |
31466 | ||
123dc839 | 31467 | @smallexample |
1780a0ed | 31468 | <target version="1.0"> |
23181151 DJ |
31469 | <architecture>i386:x86-64</architecture> |
31470 | </target> | |
123dc839 | 31471 | @end smallexample |
23181151 DJ |
31472 | |
31473 | @noindent | |
31474 | This minimal description only says that the target uses | |
31475 | the x86-64 architecture. | |
31476 | ||
123dc839 DJ |
31477 | A target description has the following overall form, with [ ] marking |
31478 | optional elements and @dots{} marking repeatable elements. The elements | |
31479 | are explained further below. | |
23181151 | 31480 | |
123dc839 | 31481 | @smallexample |
23181151 DJ |
31482 | <?xml version="1.0"?> |
31483 | <!DOCTYPE target SYSTEM "gdb-target.dtd"> | |
1780a0ed | 31484 | <target version="1.0"> |
123dc839 | 31485 | @r{[}@var{architecture}@r{]} |
08d16641 | 31486 | @r{[}@var{osabi}@r{]} |
e35359c5 | 31487 | @r{[}@var{compatible}@r{]} |
123dc839 | 31488 | @r{[}@var{feature}@dots{}@r{]} |
23181151 | 31489 | </target> |
123dc839 | 31490 | @end smallexample |
23181151 DJ |
31491 | |
31492 | @noindent | |
31493 | The description is generally insensitive to whitespace and line | |
31494 | breaks, under the usual common-sense rules. The XML version | |
31495 | declaration and document type declaration can generally be omitted | |
31496 | (@value{GDBN} does not require them), but specifying them may be | |
1780a0ed DJ |
31497 | useful for XML validation tools. The @samp{version} attribute for |
31498 | @samp{<target>} may also be omitted, but we recommend | |
31499 | including it; if future versions of @value{GDBN} use an incompatible | |
31500 | revision of @file{gdb-target.dtd}, they will detect and report | |
31501 | the version mismatch. | |
23181151 | 31502 | |
108546a0 DJ |
31503 | @subsection Inclusion |
31504 | @cindex target descriptions, inclusion | |
31505 | @cindex XInclude | |
31506 | @ifnotinfo | |
31507 | @cindex <xi:include> | |
31508 | @end ifnotinfo | |
31509 | ||
31510 | It can sometimes be valuable to split a target description up into | |
31511 | several different annexes, either for organizational purposes, or to | |
31512 | share files between different possible target descriptions. You can | |
31513 | divide a description into multiple files by replacing any element of | |
31514 | the target description with an inclusion directive of the form: | |
31515 | ||
123dc839 | 31516 | @smallexample |
108546a0 | 31517 | <xi:include href="@var{document}"/> |
123dc839 | 31518 | @end smallexample |
108546a0 DJ |
31519 | |
31520 | @noindent | |
31521 | When @value{GDBN} encounters an element of this form, it will retrieve | |
31522 | the named XML @var{document}, and replace the inclusion directive with | |
31523 | the contents of that document. If the current description was read | |
31524 | using @samp{qXfer}, then so will be the included document; | |
31525 | @var{document} will be interpreted as the name of an annex. If the | |
31526 | current description was read from a file, @value{GDBN} will look for | |
31527 | @var{document} as a file in the same directory where it found the | |
31528 | original description. | |
31529 | ||
123dc839 DJ |
31530 | @subsection Architecture |
31531 | @cindex <architecture> | |
31532 | ||
31533 | An @samp{<architecture>} element has this form: | |
31534 | ||
31535 | @smallexample | |
31536 | <architecture>@var{arch}</architecture> | |
31537 | @end smallexample | |
31538 | ||
e35359c5 UW |
31539 | @var{arch} is one of the architectures from the set accepted by |
31540 | @code{set architecture} (@pxref{Targets, ,Specifying a Debugging Target}). | |
123dc839 | 31541 | |
08d16641 PA |
31542 | @subsection OS ABI |
31543 | @cindex @code{<osabi>} | |
31544 | ||
31545 | This optional field was introduced in @value{GDBN} version 7.0. | |
31546 | Previous versions of @value{GDBN} ignore it. | |
31547 | ||
31548 | An @samp{<osabi>} element has this form: | |
31549 | ||
31550 | @smallexample | |
31551 | <osabi>@var{abi-name}</osabi> | |
31552 | @end smallexample | |
31553 | ||
31554 | @var{abi-name} is an OS ABI name from the same selection accepted by | |
31555 | @w{@code{set osabi}} (@pxref{ABI, ,Configuring the Current ABI}). | |
31556 | ||
e35359c5 UW |
31557 | @subsection Compatible Architecture |
31558 | @cindex @code{<compatible>} | |
31559 | ||
31560 | This optional field was introduced in @value{GDBN} version 7.0. | |
31561 | Previous versions of @value{GDBN} ignore it. | |
31562 | ||
31563 | A @samp{<compatible>} element has this form: | |
31564 | ||
31565 | @smallexample | |
31566 | <compatible>@var{arch}</compatible> | |
31567 | @end smallexample | |
31568 | ||
31569 | @var{arch} is one of the architectures from the set accepted by | |
31570 | @code{set architecture} (@pxref{Targets, ,Specifying a Debugging Target}). | |
31571 | ||
31572 | A @samp{<compatible>} element is used to specify that the target | |
31573 | is able to run binaries in some other than the main target architecture | |
31574 | given by the @samp{<architecture>} element. For example, on the | |
31575 | Cell Broadband Engine, the main architecture is @code{powerpc:common} | |
31576 | or @code{powerpc:common64}, but the system is able to run binaries | |
31577 | in the @code{spu} architecture as well. The way to describe this | |
31578 | capability with @samp{<compatible>} is as follows: | |
31579 | ||
31580 | @smallexample | |
31581 | <architecture>powerpc:common</architecture> | |
31582 | <compatible>spu</compatible> | |
31583 | @end smallexample | |
31584 | ||
123dc839 DJ |
31585 | @subsection Features |
31586 | @cindex <feature> | |
31587 | ||
31588 | Each @samp{<feature>} describes some logical portion of the target | |
31589 | system. Features are currently used to describe available CPU | |
31590 | registers and the types of their contents. A @samp{<feature>} element | |
31591 | has this form: | |
31592 | ||
31593 | @smallexample | |
31594 | <feature name="@var{name}"> | |
31595 | @r{[}@var{type}@dots{}@r{]} | |
31596 | @var{reg}@dots{} | |
31597 | </feature> | |
31598 | @end smallexample | |
31599 | ||
31600 | @noindent | |
31601 | Each feature's name should be unique within the description. The name | |
31602 | of a feature does not matter unless @value{GDBN} has some special | |
31603 | knowledge of the contents of that feature; if it does, the feature | |
31604 | should have its standard name. @xref{Standard Target Features}. | |
31605 | ||
31606 | @subsection Types | |
31607 | ||
31608 | Any register's value is a collection of bits which @value{GDBN} must | |
31609 | interpret. The default interpretation is a two's complement integer, | |
31610 | but other types can be requested by name in the register description. | |
31611 | Some predefined types are provided by @value{GDBN} (@pxref{Predefined | |
31612 | Target Types}), and the description can define additional composite types. | |
31613 | ||
31614 | Each type element must have an @samp{id} attribute, which gives | |
31615 | a unique (within the containing @samp{<feature>}) name to the type. | |
31616 | Types must be defined before they are used. | |
31617 | ||
31618 | @cindex <vector> | |
31619 | Some targets offer vector registers, which can be treated as arrays | |
31620 | of scalar elements. These types are written as @samp{<vector>} elements, | |
31621 | specifying the array element type, @var{type}, and the number of elements, | |
31622 | @var{count}: | |
31623 | ||
31624 | @smallexample | |
31625 | <vector id="@var{id}" type="@var{type}" count="@var{count}"/> | |
31626 | @end smallexample | |
31627 | ||
31628 | @cindex <union> | |
31629 | If a register's value is usefully viewed in multiple ways, define it | |
31630 | with a union type containing the useful representations. The | |
31631 | @samp{<union>} element contains one or more @samp{<field>} elements, | |
31632 | each of which has a @var{name} and a @var{type}: | |
31633 | ||
31634 | @smallexample | |
31635 | <union id="@var{id}"> | |
31636 | <field name="@var{name}" type="@var{type}"/> | |
31637 | @dots{} | |
31638 | </union> | |
31639 | @end smallexample | |
31640 | ||
31641 | @subsection Registers | |
31642 | @cindex <reg> | |
31643 | ||
31644 | Each register is represented as an element with this form: | |
31645 | ||
31646 | @smallexample | |
31647 | <reg name="@var{name}" | |
31648 | bitsize="@var{size}" | |
31649 | @r{[}regnum="@var{num}"@r{]} | |
31650 | @r{[}save-restore="@var{save-restore}"@r{]} | |
31651 | @r{[}type="@var{type}"@r{]} | |
31652 | @r{[}group="@var{group}"@r{]}/> | |
31653 | @end smallexample | |
31654 | ||
31655 | @noindent | |
31656 | The components are as follows: | |
31657 | ||
31658 | @table @var | |
31659 | ||
31660 | @item name | |
31661 | The register's name; it must be unique within the target description. | |
31662 | ||
31663 | @item bitsize | |
31664 | The register's size, in bits. | |
31665 | ||
31666 | @item regnum | |
31667 | The register's number. If omitted, a register's number is one greater | |
31668 | than that of the previous register (either in the current feature or in | |
31669 | a preceeding feature); the first register in the target description | |
31670 | defaults to zero. This register number is used to read or write | |
31671 | the register; e.g.@: it is used in the remote @code{p} and @code{P} | |
31672 | packets, and registers appear in the @code{g} and @code{G} packets | |
31673 | in order of increasing register number. | |
31674 | ||
31675 | @item save-restore | |
31676 | Whether the register should be preserved across inferior function | |
31677 | calls; this must be either @code{yes} or @code{no}. The default is | |
31678 | @code{yes}, which is appropriate for most registers except for | |
31679 | some system control registers; this is not related to the target's | |
31680 | ABI. | |
31681 | ||
31682 | @item type | |
31683 | The type of the register. @var{type} may be a predefined type, a type | |
31684 | defined in the current feature, or one of the special types @code{int} | |
31685 | and @code{float}. @code{int} is an integer type of the correct size | |
31686 | for @var{bitsize}, and @code{float} is a floating point type (in the | |
31687 | architecture's normal floating point format) of the correct size for | |
31688 | @var{bitsize}. The default is @code{int}. | |
31689 | ||
31690 | @item group | |
31691 | The register group to which this register belongs. @var{group} must | |
31692 | be either @code{general}, @code{float}, or @code{vector}. If no | |
31693 | @var{group} is specified, @value{GDBN} will not display the register | |
31694 | in @code{info registers}. | |
31695 | ||
31696 | @end table | |
31697 | ||
31698 | @node Predefined Target Types | |
31699 | @section Predefined Target Types | |
31700 | @cindex target descriptions, predefined types | |
31701 | ||
31702 | Type definitions in the self-description can build up composite types | |
31703 | from basic building blocks, but can not define fundamental types. Instead, | |
31704 | standard identifiers are provided by @value{GDBN} for the fundamental | |
31705 | types. The currently supported types are: | |
31706 | ||
31707 | @table @code | |
31708 | ||
31709 | @item int8 | |
31710 | @itemx int16 | |
31711 | @itemx int32 | |
31712 | @itemx int64 | |
7cc46491 | 31713 | @itemx int128 |
123dc839 DJ |
31714 | Signed integer types holding the specified number of bits. |
31715 | ||
31716 | @item uint8 | |
31717 | @itemx uint16 | |
31718 | @itemx uint32 | |
31719 | @itemx uint64 | |
7cc46491 | 31720 | @itemx uint128 |
123dc839 DJ |
31721 | Unsigned integer types holding the specified number of bits. |
31722 | ||
31723 | @item code_ptr | |
31724 | @itemx data_ptr | |
31725 | Pointers to unspecified code and data. The program counter and | |
31726 | any dedicated return address register may be marked as code | |
31727 | pointers; printing a code pointer converts it into a symbolic | |
31728 | address. The stack pointer and any dedicated address registers | |
31729 | may be marked as data pointers. | |
31730 | ||
6e3bbd1a PB |
31731 | @item ieee_single |
31732 | Single precision IEEE floating point. | |
31733 | ||
31734 | @item ieee_double | |
31735 | Double precision IEEE floating point. | |
31736 | ||
123dc839 DJ |
31737 | @item arm_fpa_ext |
31738 | The 12-byte extended precision format used by ARM FPA registers. | |
31739 | ||
31740 | @end table | |
31741 | ||
31742 | @node Standard Target Features | |
31743 | @section Standard Target Features | |
31744 | @cindex target descriptions, standard features | |
31745 | ||
31746 | A target description must contain either no registers or all the | |
31747 | target's registers. If the description contains no registers, then | |
31748 | @value{GDBN} will assume a default register layout, selected based on | |
31749 | the architecture. If the description contains any registers, the | |
31750 | default layout will not be used; the standard registers must be | |
31751 | described in the target description, in such a way that @value{GDBN} | |
31752 | can recognize them. | |
31753 | ||
31754 | This is accomplished by giving specific names to feature elements | |
31755 | which contain standard registers. @value{GDBN} will look for features | |
31756 | with those names and verify that they contain the expected registers; | |
31757 | if any known feature is missing required registers, or if any required | |
31758 | feature is missing, @value{GDBN} will reject the target | |
31759 | description. You can add additional registers to any of the | |
31760 | standard features --- @value{GDBN} will display them just as if | |
31761 | they were added to an unrecognized feature. | |
31762 | ||
31763 | This section lists the known features and their expected contents. | |
31764 | Sample XML documents for these features are included in the | |
31765 | @value{GDBN} source tree, in the directory @file{gdb/features}. | |
31766 | ||
31767 | Names recognized by @value{GDBN} should include the name of the | |
31768 | company or organization which selected the name, and the overall | |
31769 | architecture to which the feature applies; so e.g.@: the feature | |
31770 | containing ARM core registers is named @samp{org.gnu.gdb.arm.core}. | |
31771 | ||
ff6f572f DJ |
31772 | The names of registers are not case sensitive for the purpose |
31773 | of recognizing standard features, but @value{GDBN} will only display | |
31774 | registers using the capitalization used in the description. | |
31775 | ||
e9c17194 VP |
31776 | @menu |
31777 | * ARM Features:: | |
1e26b4f8 | 31778 | * MIPS Features:: |
e9c17194 | 31779 | * M68K Features:: |
1e26b4f8 | 31780 | * PowerPC Features:: |
e9c17194 VP |
31781 | @end menu |
31782 | ||
31783 | ||
31784 | @node ARM Features | |
123dc839 DJ |
31785 | @subsection ARM Features |
31786 | @cindex target descriptions, ARM features | |
31787 | ||
31788 | The @samp{org.gnu.gdb.arm.core} feature is required for ARM targets. | |
31789 | It should contain registers @samp{r0} through @samp{r13}, @samp{sp}, | |
31790 | @samp{lr}, @samp{pc}, and @samp{cpsr}. | |
31791 | ||
31792 | The @samp{org.gnu.gdb.arm.fpa} feature is optional. If present, it | |
31793 | should contain registers @samp{f0} through @samp{f7} and @samp{fps}. | |
31794 | ||
ff6f572f DJ |
31795 | The @samp{org.gnu.gdb.xscale.iwmmxt} feature is optional. If present, |
31796 | it should contain at least registers @samp{wR0} through @samp{wR15} and | |
31797 | @samp{wCGR0} through @samp{wCGR3}. The @samp{wCID}, @samp{wCon}, | |
31798 | @samp{wCSSF}, and @samp{wCASF} registers are optional. | |
23181151 | 31799 | |
58d6951d DJ |
31800 | The @samp{org.gnu.gdb.arm.vfp} feature is optional. If present, it |
31801 | should contain at least registers @samp{d0} through @samp{d15}. If | |
31802 | they are present, @samp{d16} through @samp{d31} should also be included. | |
31803 | @value{GDBN} will synthesize the single-precision registers from | |
31804 | halves of the double-precision registers. | |
31805 | ||
31806 | The @samp{org.gnu.gdb.arm.neon} feature is optional. It does not | |
31807 | need to contain registers; it instructs @value{GDBN} to display the | |
31808 | VFP double-precision registers as vectors and to synthesize the | |
31809 | quad-precision registers from pairs of double-precision registers. | |
31810 | If this feature is present, @samp{org.gnu.gdb.arm.vfp} must also | |
31811 | be present and include 32 double-precision registers. | |
31812 | ||
1e26b4f8 | 31813 | @node MIPS Features |
f8b73d13 DJ |
31814 | @subsection MIPS Features |
31815 | @cindex target descriptions, MIPS features | |
31816 | ||
31817 | The @samp{org.gnu.gdb.mips.cpu} feature is required for MIPS targets. | |
31818 | It should contain registers @samp{r0} through @samp{r31}, @samp{lo}, | |
31819 | @samp{hi}, and @samp{pc}. They may be 32-bit or 64-bit depending | |
31820 | on the target. | |
31821 | ||
31822 | The @samp{org.gnu.gdb.mips.cp0} feature is also required. It should | |
31823 | contain at least the @samp{status}, @samp{badvaddr}, and @samp{cause} | |
31824 | registers. They may be 32-bit or 64-bit depending on the target. | |
31825 | ||
31826 | The @samp{org.gnu.gdb.mips.fpu} feature is currently required, though | |
31827 | it may be optional in a future version of @value{GDBN}. It should | |
31828 | contain registers @samp{f0} through @samp{f31}, @samp{fcsr}, and | |
31829 | @samp{fir}. They may be 32-bit or 64-bit depending on the target. | |
31830 | ||
822b6570 DJ |
31831 | The @samp{org.gnu.gdb.mips.linux} feature is optional. It should |
31832 | contain a single register, @samp{restart}, which is used by the | |
31833 | Linux kernel to control restartable syscalls. | |
31834 | ||
e9c17194 VP |
31835 | @node M68K Features |
31836 | @subsection M68K Features | |
31837 | @cindex target descriptions, M68K features | |
31838 | ||
31839 | @table @code | |
31840 | @item @samp{org.gnu.gdb.m68k.core} | |
31841 | @itemx @samp{org.gnu.gdb.coldfire.core} | |
31842 | @itemx @samp{org.gnu.gdb.fido.core} | |
31843 | One of those features must be always present. | |
249e1128 | 31844 | The feature that is present determines which flavor of m68k is |
e9c17194 VP |
31845 | used. The feature that is present should contain registers |
31846 | @samp{d0} through @samp{d7}, @samp{a0} through @samp{a5}, @samp{fp}, | |
31847 | @samp{sp}, @samp{ps} and @samp{pc}. | |
31848 | ||
31849 | @item @samp{org.gnu.gdb.coldfire.fp} | |
31850 | This feature is optional. If present, it should contain registers | |
31851 | @samp{fp0} through @samp{fp7}, @samp{fpcontrol}, @samp{fpstatus} and | |
31852 | @samp{fpiaddr}. | |
31853 | @end table | |
31854 | ||
1e26b4f8 | 31855 | @node PowerPC Features |
7cc46491 DJ |
31856 | @subsection PowerPC Features |
31857 | @cindex target descriptions, PowerPC features | |
31858 | ||
31859 | The @samp{org.gnu.gdb.power.core} feature is required for PowerPC | |
31860 | targets. It should contain registers @samp{r0} through @samp{r31}, | |
31861 | @samp{pc}, @samp{msr}, @samp{cr}, @samp{lr}, @samp{ctr}, and | |
31862 | @samp{xer}. They may be 32-bit or 64-bit depending on the target. | |
31863 | ||
31864 | The @samp{org.gnu.gdb.power.fpu} feature is optional. It should | |
31865 | contain registers @samp{f0} through @samp{f31} and @samp{fpscr}. | |
31866 | ||
31867 | The @samp{org.gnu.gdb.power.altivec} feature is optional. It should | |
31868 | contain registers @samp{vr0} through @samp{vr31}, @samp{vscr}, | |
31869 | and @samp{vrsave}. | |
31870 | ||
677c5bb1 LM |
31871 | The @samp{org.gnu.gdb.power.vsx} feature is optional. It should |
31872 | contain registers @samp{vs0h} through @samp{vs31h}. @value{GDBN} | |
31873 | will combine these registers with the floating point registers | |
31874 | (@samp{f0} through @samp{f31}) and the altivec registers (@samp{vr0} | |
aeac0ff9 | 31875 | through @samp{vr31}) to present the 128-bit wide registers @samp{vs0} |
677c5bb1 LM |
31876 | through @samp{vs63}, the set of vector registers for POWER7. |
31877 | ||
7cc46491 DJ |
31878 | The @samp{org.gnu.gdb.power.spe} feature is optional. It should |
31879 | contain registers @samp{ev0h} through @samp{ev31h}, @samp{acc}, and | |
31880 | @samp{spefscr}. SPE targets should provide 32-bit registers in | |
31881 | @samp{org.gnu.gdb.power.core} and provide the upper halves in | |
31882 | @samp{ev0h} through @samp{ev31h}. @value{GDBN} will combine | |
31883 | these to present registers @samp{ev0} through @samp{ev31} to the | |
31884 | user. | |
31885 | ||
07e059b5 VP |
31886 | @node Operating System Information |
31887 | @appendix Operating System Information | |
31888 | @cindex operating system information | |
31889 | ||
31890 | @menu | |
31891 | * Process list:: | |
31892 | @end menu | |
31893 | ||
31894 | Users of @value{GDBN} often wish to obtain information about the state of | |
31895 | the operating system running on the target---for example the list of | |
31896 | processes, or the list of open files. This section describes the | |
31897 | mechanism that makes it possible. This mechanism is similar to the | |
31898 | target features mechanism (@pxref{Target Descriptions}), but focuses | |
31899 | on a different aspect of target. | |
31900 | ||
31901 | Operating system information is retrived from the target via the | |
31902 | remote protocol, using @samp{qXfer} requests (@pxref{qXfer osdata | |
31903 | read}). The object name in the request should be @samp{osdata}, and | |
31904 | the @var{annex} identifies the data to be fetched. | |
31905 | ||
31906 | @node Process list | |
31907 | @appendixsection Process list | |
31908 | @cindex operating system information, process list | |
31909 | ||
31910 | When requesting the process list, the @var{annex} field in the | |
31911 | @samp{qXfer} request should be @samp{processes}. The returned data is | |
31912 | an XML document. The formal syntax of this document is defined in | |
31913 | @file{gdb/features/osdata.dtd}. | |
31914 | ||
31915 | An example document is: | |
31916 | ||
31917 | @smallexample | |
31918 | <?xml version="1.0"?> | |
31919 | <!DOCTYPE target SYSTEM "osdata.dtd"> | |
31920 | <osdata type="processes"> | |
31921 | <item> | |
31922 | <column name="pid">1</column> | |
31923 | <column name="user">root</column> | |
31924 | <column name="command">/sbin/init</column> | |
31925 | </item> | |
31926 | </osdata> | |
31927 | @end smallexample | |
31928 | ||
31929 | Each item should include a column whose name is @samp{pid}. The value | |
31930 | of that column should identify the process on the target. The | |
31931 | @samp{user} and @samp{command} columns are optional, and will be | |
31932 | displayed by @value{GDBN}. Target may provide additional columns, | |
31933 | which @value{GDBN} currently ignores. | |
31934 | ||
aab4e0ec | 31935 | @include gpl.texi |
eb12ee30 | 31936 | |
2154891a | 31937 | @raisesections |
6826cf00 | 31938 | @include fdl.texi |
2154891a | 31939 | @lowersections |
6826cf00 | 31940 | |
6d2ebf8b | 31941 | @node Index |
c906108c SS |
31942 | @unnumbered Index |
31943 | ||
31944 | @printindex cp | |
31945 | ||
31946 | @tex | |
31947 | % I think something like @colophon should be in texinfo. In the | |
31948 | % meantime: | |
31949 | \long\def\colophon{\hbox to0pt{}\vfill | |
31950 | \centerline{The body of this manual is set in} | |
31951 | \centerline{\fontname\tenrm,} | |
31952 | \centerline{with headings in {\bf\fontname\tenbf}} | |
31953 | \centerline{and examples in {\tt\fontname\tentt}.} | |
31954 | \centerline{{\it\fontname\tenit\/},} | |
31955 | \centerline{{\bf\fontname\tenbf}, and} | |
31956 | \centerline{{\sl\fontname\tensl\/}} | |
31957 | \centerline{are used for emphasis.}\vfill} | |
31958 | \page\colophon | |
31959 | % Blame: doc@cygnus.com, 1991. | |
31960 | @end tex | |
31961 | ||
c906108c | 31962 | @bye |