Fix last change.
[deliverable/binutils-gdb.git] / gdb / doc / gdb.texinfo
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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,
7d51c7de 3@c 1999, 2000, 2001, 2002, 2003, 2004, 2005
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4@c Free Software Foundation, Inc.
5@c
5d161b24 6@c %**start of header
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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}
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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
24
41afff9a 25@c readline appendices use @vindex, @findex and @ftable,
48e934c6 26@c annotate.texi and gdbmi use @findex.
c906108c 27@syncodeindex vr cp
41afff9a 28@syncodeindex fn cp
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29
30@c !!set GDB manual's edition---not the same as GDB version!
9fe8321b 31@c This is updated by GNU Press.
e9c75b65 32@set EDITION Ninth
c906108c 33
87885426
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34@c !!set GDB edit command default editor
35@set EDITOR /bin/ex
c906108c 36
6c0e9fb3 37@c THIS MANUAL REQUIRES TEXINFO 4.0 OR LATER.
c906108c 38
c906108c 39@c This is a dir.info fragment to support semi-automated addition of
6d2ebf8b 40@c manuals to an info tree.
03727ca6 41@dircategory Software development
96a2c332 42@direntry
03727ca6 43* Gdb: (gdb). The GNU debugger.
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44@end direntry
45
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46@ifinfo
47This file documents the @sc{gnu} debugger @value{GDBN}.
48
49
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50This is the @value{EDITION} Edition, of @cite{Debugging with
51@value{GDBN}: the @sc{gnu} Source-Level Debugger} for @value{GDBN}
52Version @value{GDBVN}.
c906108c 53
8a037dd7 54Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998,@*
7d51c7de
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55 1999, 2000, 2001, 2002, 2003, 2004, 2005@*
56 Free Software Foundation, Inc.
c906108c 57
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58Permission is granted to copy, distribute and/or modify this document
59under the terms of the GNU Free Documentation License, Version 1.1 or
60any later version published by the Free Software Foundation; with the
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61Invariant Sections being ``Free Software'' and ``Free Software Needs
62Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
63and with the Back-Cover Texts as in (a) below.
c906108c 64
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65(a) The Free Software Foundation's Back-Cover Text is: ``You have
66freedom to copy and modify this GNU Manual, like GNU software. Copies
67published by the Free Software Foundation raise funds for GNU
68development.''
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69@end ifinfo
70
71@titlepage
72@title Debugging with @value{GDBN}
73@subtitle The @sc{gnu} Source-Level Debugger
c906108c 74@sp 1
c906108c 75@subtitle @value{EDITION} Edition, for @value{GDBN} version @value{GDBVN}
9e9c5ae7 76@author Richard Stallman, Roland Pesch, Stan Shebs, et al.
c906108c 77@page
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78@tex
79{\parskip=0pt
53a5351d 80\hfill (Send bugs and comments on @value{GDBN} to bug-gdb\@gnu.org.)\par
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81\hfill {\it Debugging with @value{GDBN}}\par
82\hfill \TeX{}info \texinfoversion\par
83}
84@end tex
53a5351d 85
c906108c 86@vskip 0pt plus 1filll
8a037dd7 87Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
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881996, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
89Free Software Foundation, Inc.
c906108c 90@sp 2
c906108c 91Published by the Free Software Foundation @*
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9251 Franklin Street, Fifth Floor,
93Boston, MA 02110-1301, USA@*
6d2ebf8b 94ISBN 1-882114-77-9 @*
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95
96Permission is granted to copy, distribute and/or modify this document
97under the terms of the GNU Free Documentation License, Version 1.1 or
98any later version published by the Free Software Foundation; with the
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99Invariant Sections being ``Free Software'' and ``Free Software Needs
100Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,''
101and with the Back-Cover Texts as in (a) below.
e9c75b65 102
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103(a) The Free Software Foundation's Back-Cover Text is: ``You have
104freedom to copy and modify this GNU Manual, like GNU software. Copies
105published by the Free Software Foundation raise funds for GNU
106development.''
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107@end titlepage
108@page
109
6c0e9fb3 110@ifnottex
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111@node Top, Summary, (dir), (dir)
112
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113@top Debugging with @value{GDBN}
114
115This file describes @value{GDBN}, the @sc{gnu} symbolic debugger.
116
9fe8321b 117This is the @value{EDITION} Edition, for @value{GDBN} Version
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118@value{GDBVN}.
119
7d51c7de 120Copyright (C) 1988-2005 Free Software Foundation, Inc.
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121
122@menu
123* Summary:: Summary of @value{GDBN}
124* Sample Session:: A sample @value{GDBN} session
125
126* Invocation:: Getting in and out of @value{GDBN}
127* Commands:: @value{GDBN} commands
128* Running:: Running programs under @value{GDBN}
129* Stopping:: Stopping and continuing
130* Stack:: Examining the stack
131* Source:: Examining source files
132* Data:: Examining data
e2e0bcd1 133* Macros:: Preprocessor Macros
b37052ae 134* Tracepoints:: Debugging remote targets non-intrusively
df0cd8c5 135* Overlays:: Debugging programs that use overlays
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136
137* Languages:: Using @value{GDBN} with different languages
138
139* Symbols:: Examining the symbol table
140* Altering:: Altering execution
141* GDB Files:: @value{GDBN} files
142* Targets:: Specifying a debugging target
6b2f586d 143* Remote Debugging:: Debugging remote programs
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144* Configurations:: Configuration-specific information
145* Controlling GDB:: Controlling @value{GDBN}
146* Sequences:: Canned sequences of commands
c4555f82 147* TUI:: @value{GDBN} Text User Interface
21c294e6 148* Interpreters:: Command Interpreters
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149* Emacs:: Using @value{GDBN} under @sc{gnu} Emacs
150* Annotations:: @value{GDBN}'s annotation interface.
7162c0ca 151* GDB/MI:: @value{GDBN}'s Machine Interface.
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152
153* GDB Bugs:: Reporting bugs in @value{GDBN}
154* Formatting Documentation:: How to format and print @value{GDBN} documentation
155
156* Command Line Editing:: Command Line Editing
157* Using History Interactively:: Using History Interactively
158* Installing GDB:: Installing GDB
eb12ee30 159* Maintenance Commands:: Maintenance Commands
e0ce93ac 160* Remote Protocol:: GDB Remote Serial Protocol
f418dd93 161* Agent Expressions:: The GDB Agent Expression Mechanism
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162* Copying:: GNU General Public License says
163 how you can copy and share GDB
6826cf00 164* GNU Free Documentation License:: The license for this documentation
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165* Index:: Index
166@end menu
167
6c0e9fb3 168@end ifnottex
c906108c 169
449f3b6c 170@contents
449f3b6c 171
6d2ebf8b 172@node Summary
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173@unnumbered Summary of @value{GDBN}
174
175The purpose of a debugger such as @value{GDBN} is to allow you to see what is
176going on ``inside'' another program while it executes---or what another
177program was doing at the moment it crashed.
178
179@value{GDBN} can do four main kinds of things (plus other things in support of
180these) to help you catch bugs in the act:
181
182@itemize @bullet
183@item
184Start your program, specifying anything that might affect its behavior.
185
186@item
187Make your program stop on specified conditions.
188
189@item
190Examine what has happened, when your program has stopped.
191
192@item
193Change things in your program, so you can experiment with correcting the
194effects of one bug and go on to learn about another.
195@end itemize
196
49efadf5 197You can use @value{GDBN} to debug programs written in C and C@t{++}.
9c16f35a 198For more information, see @ref{Supported languages,,Supported languages}.
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199For more information, see @ref{C,,C and C++}.
200
cce74817 201@cindex Modula-2
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202Support for Modula-2 is partial. For information on Modula-2, see
203@ref{Modula-2,,Modula-2}.
c906108c 204
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205@cindex Pascal
206Debugging Pascal programs which use sets, subranges, file variables, or
207nested functions does not currently work. @value{GDBN} does not support
208entering expressions, printing values, or similar features using Pascal
209syntax.
c906108c 210
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211@cindex Fortran
212@value{GDBN} can be used to debug programs written in Fortran, although
53a5351d 213it may be necessary to refer to some variables with a trailing
cce74817 214underscore.
c906108c 215
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216@value{GDBN} can be used to debug programs written in Objective-C,
217using either the Apple/NeXT or the GNU Objective-C runtime.
218
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219@menu
220* Free Software:: Freely redistributable software
221* Contributors:: Contributors to GDB
222@end menu
223
6d2ebf8b 224@node Free Software
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225@unnumberedsec Free software
226
5d161b24 227@value{GDBN} is @dfn{free software}, protected by the @sc{gnu}
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228General Public License
229(GPL). The GPL gives you the freedom to copy or adapt a licensed
230program---but every person getting a copy also gets with it the
231freedom to modify that copy (which means that they must get access to
232the source code), and the freedom to distribute further copies.
233Typical software companies use copyrights to limit your freedoms; the
234Free Software Foundation uses the GPL to preserve these freedoms.
235
236Fundamentally, the General Public License is a license which says that
237you have these freedoms and that you cannot take these freedoms away
238from anyone else.
239
2666264b 240@unnumberedsec Free Software Needs Free Documentation
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241
242The biggest deficiency in the free software community today is not in
243the software---it is the lack of good free documentation that we can
244include with the free software. Many of our most important
245programs do not come with free reference manuals and free introductory
246texts. Documentation is an essential part of any software package;
247when an important free software package does not come with a free
248manual and a free tutorial, that is a major gap. We have many such
249gaps today.
250
251Consider Perl, for instance. The tutorial manuals that people
252normally use are non-free. How did this come about? Because the
253authors of those manuals published them with restrictive terms---no
254copying, no modification, source files not available---which exclude
255them from the free software world.
256
257That wasn't the first time this sort of thing happened, and it was far
258from the last. Many times we have heard a GNU user eagerly describe a
259manual that he is writing, his intended contribution to the community,
260only to learn that he had ruined everything by signing a publication
261contract to make it non-free.
262
263Free documentation, like free software, is a matter of freedom, not
264price. The problem with the non-free manual is not that publishers
265charge a price for printed copies---that in itself is fine. (The Free
266Software Foundation sells printed copies of manuals, too.) The
267problem is the restrictions on the use of the manual. Free manuals
268are available in source code form, and give you permission to copy and
269modify. Non-free manuals do not allow this.
270
271The criteria of freedom for a free manual are roughly the same as for
272free software. Redistribution (including the normal kinds of
273commercial redistribution) must be permitted, so that the manual can
274accompany every copy of the program, both on-line and on paper.
275
276Permission for modification of the technical content is crucial too.
277When people modify the software, adding or changing features, if they
278are conscientious they will change the manual too---so they can
279provide accurate and clear documentation for the modified program. A
280manual that leaves you no choice but to write a new manual to document
281a changed version of the program is not really available to our
282community.
283
284Some kinds of limits on the way modification is handled are
285acceptable. For example, requirements to preserve the original
286author's copyright notice, the distribution terms, or the list of
287authors, are ok. It is also no problem to require modified versions
288to include notice that they were modified. Even entire sections that
289may not be deleted or changed are acceptable, as long as they deal
290with nontechnical topics (like this one). These kinds of restrictions
291are acceptable because they don't obstruct the community's normal use
292of the manual.
293
294However, it must be possible to modify all the @emph{technical}
295content of the manual, and then distribute the result in all the usual
296media, through all the usual channels. Otherwise, the restrictions
297obstruct the use of the manual, it is not free, and we need another
298manual to replace it.
299
300Please spread the word about this issue. Our community continues to
301lose manuals to proprietary publishing. If we spread the word that
302free software needs free reference manuals and free tutorials, perhaps
303the next person who wants to contribute by writing documentation will
304realize, before it is too late, that only free manuals contribute to
305the free software community.
306
307If you are writing documentation, please insist on publishing it under
308the GNU Free Documentation License or another free documentation
309license. Remember that this decision requires your approval---you
310don't have to let the publisher decide. Some commercial publishers
311will use a free license if you insist, but they will not propose the
312option; it is up to you to raise the issue and say firmly that this is
313what you want. If the publisher you are dealing with refuses, please
314try other publishers. If you're not sure whether a proposed license
42584a72 315is free, write to @email{licensing@@gnu.org}.
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316
317You can encourage commercial publishers to sell more free, copylefted
318manuals and tutorials by buying them, and particularly by buying
319copies from the publishers that paid for their writing or for major
320improvements. Meanwhile, try to avoid buying non-free documentation
321at all. Check the distribution terms of a manual before you buy it,
322and insist that whoever seeks your business must respect your freedom.
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323Check the history of the book, and try to reward the publishers that
324have paid or pay the authors to work on it.
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325
326The Free Software Foundation maintains a list of free documentation
327published by other publishers, at
328@url{http://www.fsf.org/doc/other-free-books.html}.
329
6d2ebf8b 330@node Contributors
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331@unnumberedsec Contributors to @value{GDBN}
332
333Richard Stallman was the original author of @value{GDBN}, and of many
334other @sc{gnu} programs. Many others have contributed to its
335development. This section attempts to credit major contributors. One
336of the virtues of free software is that everyone is free to contribute
337to it; with regret, we cannot actually acknowledge everyone here. The
338file @file{ChangeLog} in the @value{GDBN} distribution approximates a
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339blow-by-blow account.
340
341Changes much prior to version 2.0 are lost in the mists of time.
342
343@quotation
344@emph{Plea:} Additions to this section are particularly welcome. If you
345or your friends (or enemies, to be evenhanded) have been unfairly
346omitted from this list, we would like to add your names!
347@end quotation
348
349So that they may not regard their many labors as thankless, we
350particularly thank those who shepherded @value{GDBN} through major
351releases:
7ba3cf9c 352Andrew Cagney (releases 6.3, 6.2, 6.1, 6.0, 5.3, 5.2, 5.1 and 5.0);
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353Jim Blandy (release 4.18);
354Jason Molenda (release 4.17);
355Stan Shebs (release 4.14);
356Fred Fish (releases 4.16, 4.15, 4.13, 4.12, 4.11, 4.10, and 4.9);
357Stu Grossman and John Gilmore (releases 4.8, 4.7, 4.6, 4.5, and 4.4);
358John Gilmore (releases 4.3, 4.2, 4.1, 4.0, and 3.9);
359Jim Kingdon (releases 3.5, 3.4, and 3.3);
360and Randy Smith (releases 3.2, 3.1, and 3.0).
361
362Richard Stallman, assisted at various times by Peter TerMaat, Chris
363Hanson, and Richard Mlynarik, handled releases through 2.8.
364
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365Michael Tiemann is the author of most of the @sc{gnu} C@t{++} support
366in @value{GDBN}, with significant additional contributions from Per
367Bothner and Daniel Berlin. James Clark wrote the @sc{gnu} C@t{++}
368demangler. Early work on C@t{++} was by Peter TerMaat (who also did
369much general update work leading to release 3.0).
c906108c 370
b37052ae 371@value{GDBN} uses the BFD subroutine library to examine multiple
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372object-file formats; BFD was a joint project of David V.
373Henkel-Wallace, Rich Pixley, Steve Chamberlain, and John Gilmore.
374
375David Johnson wrote the original COFF support; Pace Willison did
376the original support for encapsulated COFF.
377
0179ffac 378Brent Benson of Harris Computer Systems contributed DWARF 2 support.
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379
380Adam de Boor and Bradley Davis contributed the ISI Optimum V support.
381Per Bothner, Noboyuki Hikichi, and Alessandro Forin contributed MIPS
382support.
383Jean-Daniel Fekete contributed Sun 386i support.
384Chris Hanson improved the HP9000 support.
385Noboyuki Hikichi and Tomoyuki Hasei contributed Sony/News OS 3 support.
386David Johnson contributed Encore Umax support.
387Jyrki Kuoppala contributed Altos 3068 support.
388Jeff Law contributed HP PA and SOM support.
389Keith Packard contributed NS32K support.
390Doug Rabson contributed Acorn Risc Machine support.
391Bob Rusk contributed Harris Nighthawk CX-UX support.
392Chris Smith contributed Convex support (and Fortran debugging).
393Jonathan Stone contributed Pyramid support.
394Michael Tiemann contributed SPARC support.
395Tim Tucker contributed support for the Gould NP1 and Gould Powernode.
396Pace Willison contributed Intel 386 support.
397Jay Vosburgh contributed Symmetry support.
a37295f9 398Marko Mlinar contributed OpenRISC 1000 support.
c906108c 399
1104b9e7 400Andreas Schwab contributed M68K @sc{gnu}/Linux support.
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401
402Rich Schaefer and Peter Schauer helped with support of SunOS shared
403libraries.
404
405Jay Fenlason and Roland McGrath ensured that @value{GDBN} and GAS agree
406about several machine instruction sets.
407
408Patrick Duval, Ted Goldstein, Vikram Koka and Glenn Engel helped develop
409remote debugging. Intel Corporation, Wind River Systems, AMD, and ARM
410contributed remote debugging modules for the i960, VxWorks, A29K UDI,
411and RDI targets, respectively.
412
413Brian Fox is the author of the readline libraries providing
414command-line editing and command history.
415
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416Andrew Beers of SUNY Buffalo wrote the language-switching code, the
417Modula-2 support, and contributed the Languages chapter of this manual.
c906108c 418
5d161b24 419Fred Fish wrote most of the support for Unix System Vr4.
b37052ae 420He also enhanced the command-completion support to cover C@t{++} overloaded
c906108c 421symbols.
c906108c 422
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423Hitachi America (now Renesas America), Ltd. sponsored the support for
424H8/300, H8/500, and Super-H processors.
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425
426NEC sponsored the support for the v850, Vr4xxx, and Vr5xxx processors.
427
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428Mitsubishi (now Renesas) sponsored the support for D10V, D30V, and M32R/D
429processors.
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430
431Toshiba sponsored the support for the TX39 Mips processor.
432
433Matsushita sponsored the support for the MN10200 and MN10300 processors.
434
96a2c332 435Fujitsu sponsored the support for SPARClite and FR30 processors.
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436
437Kung Hsu, Jeff Law, and Rick Sladkey added support for hardware
438watchpoints.
439
440Michael Snyder added support for tracepoints.
441
442Stu Grossman wrote gdbserver.
443
444Jim Kingdon, Peter Schauer, Ian Taylor, and Stu Grossman made
96a2c332 445nearly innumerable bug fixes and cleanups throughout @value{GDBN}.
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446
447The following people at the Hewlett-Packard Company contributed
448support for the PA-RISC 2.0 architecture, HP-UX 10.20, 10.30, and 11.0
b37052ae 449(narrow mode), HP's implementation of kernel threads, HP's aC@t{++}
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450compiler, and the Text User Interface (nee Terminal User Interface):
451Ben Krepp, Richard Title, John Bishop, Susan Macchia, Kathy Mann,
452Satish Pai, India Paul, Steve Rehrauer, and Elena Zannoni. Kim Haase
453provided HP-specific information in this manual.
c906108c 454
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455DJ Delorie ported @value{GDBN} to MS-DOS, for the DJGPP project.
456Robert Hoehne made significant contributions to the DJGPP port.
457
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458Cygnus Solutions has sponsored @value{GDBN} maintenance and much of its
459development since 1991. Cygnus engineers who have worked on @value{GDBN}
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460fulltime include Mark Alexander, Jim Blandy, Per Bothner, Kevin
461Buettner, Edith Epstein, Chris Faylor, Fred Fish, Martin Hunt, Jim
462Ingham, John Gilmore, Stu Grossman, Kung Hsu, Jim Kingdon, John Metzler,
463Fernando Nasser, Geoffrey Noer, Dawn Perchik, Rich Pixley, Zdenek
464Radouch, Keith Seitz, Stan Shebs, David Taylor, and Elena Zannoni. In
465addition, Dave Brolley, Ian Carmichael, Steve Chamberlain, Nick Clifton,
466JT Conklin, Stan Cox, DJ Delorie, Ulrich Drepper, Frank Eigler, Doug
467Evans, Sean Fagan, David Henkel-Wallace, Richard Henderson, Jeff
468Holcomb, Jeff Law, Jim Lemke, Tom Lord, Bob Manson, Michael Meissner,
469Jason Merrill, Catherine Moore, Drew Moseley, Ken Raeburn, Gavin
470Romig-Koch, Rob Savoye, Jamie Smith, Mike Stump, Ian Taylor, Angela
471Thomas, Michael Tiemann, Tom Tromey, Ron Unrau, Jim Wilson, and David
472Zuhn have made contributions both large and small.
c906108c 473
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474Andrew Cagney, Fernando Nasser, and Elena Zannoni, while working for
475Cygnus Solutions, implemented the original @sc{gdb/mi} interface.
476
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477Jim Blandy added support for preprocessor macros, while working for Red
478Hat.
c906108c 479
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480Andrew Cagney designed @value{GDBN}'s architecture vector. Many
481people including Andrew Cagney, Stephane Carrez, Randolph Chung, Nick
482Duffek, Richard Henderson, Mark Kettenis, Grace Sainsbury, Kei
483Sakamoto, Yoshinori Sato, Michael Snyder, Andreas Schwab, Jason
484Thorpe, Corinna Vinschen, Ulrich Weigand, and Elena Zannoni, helped
485with the migration of old architectures to this new framework.
486
6d2ebf8b 487@node Sample Session
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488@chapter A Sample @value{GDBN} Session
489
490You can use this manual at your leisure to read all about @value{GDBN}.
491However, a handful of commands are enough to get started using the
492debugger. This chapter illustrates those commands.
493
494@iftex
495In this sample session, we emphasize user input like this: @b{input},
496to make it easier to pick out from the surrounding output.
497@end iftex
498
499@c FIXME: this example may not be appropriate for some configs, where
500@c FIXME...primary interest is in remote use.
501
502One of the preliminary versions of @sc{gnu} @code{m4} (a generic macro
503processor) exhibits the following bug: sometimes, when we change its
504quote strings from the default, the commands used to capture one macro
505definition within another stop working. In the following short @code{m4}
506session, we define a macro @code{foo} which expands to @code{0000}; we
507then use the @code{m4} built-in @code{defn} to define @code{bar} as the
508same thing. However, when we change the open quote string to
509@code{<QUOTE>} and the close quote string to @code{<UNQUOTE>}, the same
510procedure fails to define a new synonym @code{baz}:
511
512@smallexample
513$ @b{cd gnu/m4}
514$ @b{./m4}
515@b{define(foo,0000)}
516
517@b{foo}
5180000
519@b{define(bar,defn(`foo'))}
520
521@b{bar}
5220000
523@b{changequote(<QUOTE>,<UNQUOTE>)}
524
525@b{define(baz,defn(<QUOTE>foo<UNQUOTE>))}
526@b{baz}
527@b{C-d}
528m4: End of input: 0: fatal error: EOF in string
529@end smallexample
530
531@noindent
532Let us use @value{GDBN} to try to see what is going on.
533
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534@smallexample
535$ @b{@value{GDBP} m4}
536@c FIXME: this falsifies the exact text played out, to permit smallbook
537@c FIXME... format to come out better.
538@value{GDBN} is free software and you are welcome to distribute copies
5d161b24 539 of it under certain conditions; type "show copying" to see
c906108c 540 the conditions.
5d161b24 541There is absolutely no warranty for @value{GDBN}; type "show warranty"
c906108c
SS
542 for details.
543
544@value{GDBN} @value{GDBVN}, Copyright 1999 Free Software Foundation, Inc...
545(@value{GDBP})
546@end smallexample
c906108c
SS
547
548@noindent
549@value{GDBN} reads only enough symbol data to know where to find the
550rest when needed; as a result, the first prompt comes up very quickly.
551We now tell @value{GDBN} to use a narrower display width than usual, so
552that examples fit in this manual.
553
554@smallexample
555(@value{GDBP}) @b{set width 70}
556@end smallexample
557
558@noindent
559We need to see how the @code{m4} built-in @code{changequote} works.
560Having looked at the source, we know the relevant subroutine is
561@code{m4_changequote}, so we set a breakpoint there with the @value{GDBN}
562@code{break} command.
563
564@smallexample
565(@value{GDBP}) @b{break m4_changequote}
566Breakpoint 1 at 0x62f4: file builtin.c, line 879.
567@end smallexample
568
569@noindent
570Using the @code{run} command, we start @code{m4} running under @value{GDBN}
571control; as long as control does not reach the @code{m4_changequote}
572subroutine, the program runs as usual:
573
574@smallexample
575(@value{GDBP}) @b{run}
576Starting program: /work/Editorial/gdb/gnu/m4/m4
577@b{define(foo,0000)}
578
579@b{foo}
5800000
581@end smallexample
582
583@noindent
584To trigger the breakpoint, we call @code{changequote}. @value{GDBN}
585suspends execution of @code{m4}, displaying information about the
586context where it stops.
587
588@smallexample
589@b{changequote(<QUOTE>,<UNQUOTE>)}
590
5d161b24 591Breakpoint 1, m4_changequote (argc=3, argv=0x33c70)
c906108c
SS
592 at builtin.c:879
593879 if (bad_argc(TOKEN_DATA_TEXT(argv[0]),argc,1,3))
594@end smallexample
595
596@noindent
597Now we use the command @code{n} (@code{next}) to advance execution to
598the next line of the current function.
599
600@smallexample
601(@value{GDBP}) @b{n}
602882 set_quotes((argc >= 2) ? TOKEN_DATA_TEXT(argv[1])\
603 : nil,
604@end smallexample
605
606@noindent
607@code{set_quotes} looks like a promising subroutine. We can go into it
608by using the command @code{s} (@code{step}) instead of @code{next}.
609@code{step} goes to the next line to be executed in @emph{any}
610subroutine, so it steps into @code{set_quotes}.
611
612@smallexample
613(@value{GDBP}) @b{s}
614set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>")
615 at input.c:530
616530 if (lquote != def_lquote)
617@end smallexample
618
619@noindent
620The display that shows the subroutine where @code{m4} is now
621suspended (and its arguments) is called a stack frame display. It
622shows a summary of the stack. We can use the @code{backtrace}
623command (which can also be spelled @code{bt}), to see where we are
624in the stack as a whole: the @code{backtrace} command displays a
625stack frame for each active subroutine.
626
627@smallexample
628(@value{GDBP}) @b{bt}
629#0 set_quotes (lq=0x34c78 "<QUOTE>", rq=0x34c88 "<UNQUOTE>")
630 at input.c:530
5d161b24 631#1 0x6344 in m4_changequote (argc=3, argv=0x33c70)
c906108c
SS
632 at builtin.c:882
633#2 0x8174 in expand_macro (sym=0x33320) at macro.c:242
634#3 0x7a88 in expand_token (obs=0x0, t=209696, td=0xf7fffa30)
635 at macro.c:71
636#4 0x79dc in expand_input () at macro.c:40
637#5 0x2930 in main (argc=0, argv=0xf7fffb20) at m4.c:195
638@end smallexample
639
640@noindent
641We step through a few more lines to see what happens. The first two
642times, we can use @samp{s}; the next two times we use @code{n} to avoid
643falling into the @code{xstrdup} subroutine.
644
645@smallexample
646(@value{GDBP}) @b{s}
6470x3b5c 532 if (rquote != def_rquote)
648(@value{GDBP}) @b{s}
6490x3b80 535 lquote = (lq == nil || *lq == '\0') ? \
650def_lquote : xstrdup(lq);
651(@value{GDBP}) @b{n}
652536 rquote = (rq == nil || *rq == '\0') ? def_rquote\
653 : xstrdup(rq);
654(@value{GDBP}) @b{n}
655538 len_lquote = strlen(rquote);
656@end smallexample
657
658@noindent
659The last line displayed looks a little odd; we can examine the variables
660@code{lquote} and @code{rquote} to see if they are in fact the new left
661and right quotes we specified. We use the command @code{p}
662(@code{print}) to see their values.
663
664@smallexample
665(@value{GDBP}) @b{p lquote}
666$1 = 0x35d40 "<QUOTE>"
667(@value{GDBP}) @b{p rquote}
668$2 = 0x35d50 "<UNQUOTE>"
669@end smallexample
670
671@noindent
672@code{lquote} and @code{rquote} are indeed the new left and right quotes.
673To look at some context, we can display ten lines of source
674surrounding the current line with the @code{l} (@code{list}) command.
675
676@smallexample
677(@value{GDBP}) @b{l}
678533 xfree(rquote);
679534
680535 lquote = (lq == nil || *lq == '\0') ? def_lquote\
681 : xstrdup (lq);
682536 rquote = (rq == nil || *rq == '\0') ? def_rquote\
683 : xstrdup (rq);
684537
685538 len_lquote = strlen(rquote);
686539 len_rquote = strlen(lquote);
687540 @}
688541
689542 void
690@end smallexample
691
692@noindent
693Let us step past the two lines that set @code{len_lquote} and
694@code{len_rquote}, and then examine the values of those variables.
695
696@smallexample
697(@value{GDBP}) @b{n}
698539 len_rquote = strlen(lquote);
699(@value{GDBP}) @b{n}
700540 @}
701(@value{GDBP}) @b{p len_lquote}
702$3 = 9
703(@value{GDBP}) @b{p len_rquote}
704$4 = 7
705@end smallexample
706
707@noindent
708That certainly looks wrong, assuming @code{len_lquote} and
709@code{len_rquote} are meant to be the lengths of @code{lquote} and
710@code{rquote} respectively. We can set them to better values using
711the @code{p} command, since it can print the value of
712any expression---and that expression can include subroutine calls and
713assignments.
714
715@smallexample
716(@value{GDBP}) @b{p len_lquote=strlen(lquote)}
717$5 = 7
718(@value{GDBP}) @b{p len_rquote=strlen(rquote)}
719$6 = 9
720@end smallexample
721
722@noindent
723Is that enough to fix the problem of using the new quotes with the
724@code{m4} built-in @code{defn}? We can allow @code{m4} to continue
725executing with the @code{c} (@code{continue}) command, and then try the
726example that caused trouble initially:
727
728@smallexample
729(@value{GDBP}) @b{c}
730Continuing.
731
732@b{define(baz,defn(<QUOTE>foo<UNQUOTE>))}
733
734baz
7350000
736@end smallexample
737
738@noindent
739Success! The new quotes now work just as well as the default ones. The
740problem seems to have been just the two typos defining the wrong
741lengths. We allow @code{m4} exit by giving it an EOF as input:
742
743@smallexample
744@b{C-d}
745Program exited normally.
746@end smallexample
747
748@noindent
749The message @samp{Program exited normally.} is from @value{GDBN}; it
750indicates @code{m4} has finished executing. We can end our @value{GDBN}
751session with the @value{GDBN} @code{quit} command.
752
753@smallexample
754(@value{GDBP}) @b{quit}
755@end smallexample
c906108c 756
6d2ebf8b 757@node Invocation
c906108c
SS
758@chapter Getting In and Out of @value{GDBN}
759
760This chapter discusses how to start @value{GDBN}, and how to get out of it.
5d161b24 761The essentials are:
c906108c 762@itemize @bullet
5d161b24 763@item
53a5351d 764type @samp{@value{GDBP}} to start @value{GDBN}.
5d161b24 765@item
c906108c
SS
766type @kbd{quit} or @kbd{C-d} to exit.
767@end itemize
768
769@menu
770* Invoking GDB:: How to start @value{GDBN}
771* Quitting GDB:: How to quit @value{GDBN}
772* Shell Commands:: How to use shell commands inside @value{GDBN}
0fac0b41 773* Logging output:: How to log @value{GDBN}'s output to a file
c906108c
SS
774@end menu
775
6d2ebf8b 776@node Invoking GDB
c906108c
SS
777@section Invoking @value{GDBN}
778
c906108c
SS
779Invoke @value{GDBN} by running the program @code{@value{GDBP}}. Once started,
780@value{GDBN} reads commands from the terminal until you tell it to exit.
781
782You can also run @code{@value{GDBP}} with a variety of arguments and options,
783to specify more of your debugging environment at the outset.
784
c906108c
SS
785The command-line options described here are designed
786to cover a variety of situations; in some environments, some of these
5d161b24 787options may effectively be unavailable.
c906108c
SS
788
789The most usual way to start @value{GDBN} is with one argument,
790specifying an executable program:
791
474c8240 792@smallexample
c906108c 793@value{GDBP} @var{program}
474c8240 794@end smallexample
c906108c 795
c906108c
SS
796@noindent
797You can also start with both an executable program and a core file
798specified:
799
474c8240 800@smallexample
c906108c 801@value{GDBP} @var{program} @var{core}
474c8240 802@end smallexample
c906108c
SS
803
804You can, instead, specify a process ID as a second argument, if you want
805to debug a running process:
806
474c8240 807@smallexample
c906108c 808@value{GDBP} @var{program} 1234
474c8240 809@end smallexample
c906108c
SS
810
811@noindent
812would attach @value{GDBN} to process @code{1234} (unless you also have a file
813named @file{1234}; @value{GDBN} does check for a core file first).
814
c906108c 815Taking advantage of the second command-line argument requires a fairly
2df3850c
JM
816complete operating system; when you use @value{GDBN} as a remote
817debugger attached to a bare board, there may not be any notion of
818``process'', and there is often no way to get a core dump. @value{GDBN}
819will warn you if it is unable to attach or to read core dumps.
c906108c 820
aa26fa3a
TT
821You can optionally have @code{@value{GDBP}} pass any arguments after the
822executable file to the inferior using @code{--args}. This option stops
823option processing.
474c8240 824@smallexample
aa26fa3a 825gdb --args gcc -O2 -c foo.c
474c8240 826@end smallexample
aa26fa3a
TT
827This will cause @code{@value{GDBP}} to debug @code{gcc}, and to set
828@code{gcc}'s command-line arguments (@pxref{Arguments}) to @samp{-O2 -c foo.c}.
829
96a2c332 830You can run @code{@value{GDBP}} without printing the front material, which describes
c906108c
SS
831@value{GDBN}'s non-warranty, by specifying @code{-silent}:
832
833@smallexample
834@value{GDBP} -silent
835@end smallexample
836
837@noindent
838You can further control how @value{GDBN} starts up by using command-line
839options. @value{GDBN} itself can remind you of the options available.
840
841@noindent
842Type
843
474c8240 844@smallexample
c906108c 845@value{GDBP} -help
474c8240 846@end smallexample
c906108c
SS
847
848@noindent
849to display all available options and briefly describe their use
850(@samp{@value{GDBP} -h} is a shorter equivalent).
851
852All options and command line arguments you give are processed
853in sequential order. The order makes a difference when the
854@samp{-x} option is used.
855
856
857@menu
c906108c
SS
858* File Options:: Choosing files
859* Mode Options:: Choosing modes
6fc08d32 860* Startup:: What @value{GDBN} does during startup
c906108c
SS
861@end menu
862
6d2ebf8b 863@node File Options
c906108c
SS
864@subsection Choosing files
865
2df3850c 866When @value{GDBN} starts, it reads any arguments other than options as
c906108c
SS
867specifying an executable file and core file (or process ID). This is
868the same as if the arguments were specified by the @samp{-se} and
19837790
MS
869@samp{-c} (or @samp{-p} options respectively. (@value{GDBN} reads the
870first argument that does not have an associated option flag as
871equivalent to the @samp{-se} option followed by that argument; and the
872second argument that does not have an associated option flag, if any, as
873equivalent to the @samp{-c}/@samp{-p} option followed by that argument.)
874If the second argument begins with a decimal digit, @value{GDBN} will
875first attempt to attach to it as a process, and if that fails, attempt
876to open it as a corefile. If you have a corefile whose name begins with
b383017d 877a digit, you can prevent @value{GDBN} from treating it as a pid by
c1468174 878prefixing it with @file{./}, e.g.@: @file{./12345}.
7a292a7a
SS
879
880If @value{GDBN} has not been configured to included core file support,
881such as for most embedded targets, then it will complain about a second
882argument and ignore it.
c906108c
SS
883
884Many options have both long and short forms; both are shown in the
885following list. @value{GDBN} also recognizes the long forms if you truncate
886them, so long as enough of the option is present to be unambiguous.
887(If you prefer, you can flag option arguments with @samp{--} rather
888than @samp{-}, though we illustrate the more usual convention.)
889
d700128c
EZ
890@c NOTE: the @cindex entries here use double dashes ON PURPOSE. This
891@c way, both those who look for -foo and --foo in the index, will find
892@c it.
893
c906108c
SS
894@table @code
895@item -symbols @var{file}
896@itemx -s @var{file}
d700128c
EZ
897@cindex @code{--symbols}
898@cindex @code{-s}
c906108c
SS
899Read symbol table from file @var{file}.
900
901@item -exec @var{file}
902@itemx -e @var{file}
d700128c
EZ
903@cindex @code{--exec}
904@cindex @code{-e}
7a292a7a
SS
905Use file @var{file} as the executable file to execute when appropriate,
906and for examining pure data in conjunction with a core dump.
c906108c
SS
907
908@item -se @var{file}
d700128c 909@cindex @code{--se}
c906108c
SS
910Read symbol table from file @var{file} and use it as the executable
911file.
912
c906108c
SS
913@item -core @var{file}
914@itemx -c @var{file}
d700128c
EZ
915@cindex @code{--core}
916@cindex @code{-c}
b383017d 917Use file @var{file} as a core dump to examine.
c906108c
SS
918
919@item -c @var{number}
19837790
MS
920@item -pid @var{number}
921@itemx -p @var{number}
922@cindex @code{--pid}
923@cindex @code{-p}
924Connect to process ID @var{number}, as with the @code{attach} command.
925If there is no such process, @value{GDBN} will attempt to open a core
926file named @var{number}.
c906108c
SS
927
928@item -command @var{file}
929@itemx -x @var{file}
d700128c
EZ
930@cindex @code{--command}
931@cindex @code{-x}
c906108c
SS
932Execute @value{GDBN} commands from file @var{file}. @xref{Command
933Files,, Command files}.
934
8a5a3c82
AS
935@item -eval-command @var{command}
936@itemx -ex @var{command}
937@cindex @code{--eval-command}
938@cindex @code{-ex}
939Execute a single @value{GDBN} command.
940
941This option may be used multiple times to call multiple commands. It may
942also be interleaved with @samp{-command} as required.
943
944@smallexample
945@value{GDBP} -ex 'target sim' -ex 'load' \
946 -x setbreakpoints -ex 'run' a.out
947@end smallexample
948
c906108c
SS
949@item -directory @var{directory}
950@itemx -d @var{directory}
d700128c
EZ
951@cindex @code{--directory}
952@cindex @code{-d}
4b505b12 953Add @var{directory} to the path to search for source and script files.
c906108c 954
c906108c
SS
955@item -r
956@itemx -readnow
d700128c
EZ
957@cindex @code{--readnow}
958@cindex @code{-r}
c906108c
SS
959Read each symbol file's entire symbol table immediately, rather than
960the default, which is to read it incrementally as it is needed.
961This makes startup slower, but makes future operations faster.
53a5351d 962
c906108c
SS
963@end table
964
6d2ebf8b 965@node Mode Options
c906108c
SS
966@subsection Choosing modes
967
968You can run @value{GDBN} in various alternative modes---for example, in
969batch mode or quiet mode.
970
971@table @code
972@item -nx
973@itemx -n
d700128c
EZ
974@cindex @code{--nx}
975@cindex @code{-n}
96565e91 976Do not execute commands found in any initialization files. Normally,
2df3850c
JM
977@value{GDBN} executes the commands in these files after all the command
978options and arguments have been processed. @xref{Command Files,,Command
979files}.
c906108c
SS
980
981@item -quiet
d700128c 982@itemx -silent
c906108c 983@itemx -q
d700128c
EZ
984@cindex @code{--quiet}
985@cindex @code{--silent}
986@cindex @code{-q}
c906108c
SS
987``Quiet''. Do not print the introductory and copyright messages. These
988messages are also suppressed in batch mode.
989
990@item -batch
d700128c 991@cindex @code{--batch}
c906108c
SS
992Run in batch mode. Exit with status @code{0} after processing all the
993command files specified with @samp{-x} (and all commands from
994initialization files, if not inhibited with @samp{-n}). Exit with
995nonzero status if an error occurs in executing the @value{GDBN} commands
996in the command files.
997
2df3850c
JM
998Batch mode may be useful for running @value{GDBN} as a filter, for
999example to download and run a program on another computer; in order to
1000make this more useful, the message
c906108c 1001
474c8240 1002@smallexample
c906108c 1003Program exited normally.
474c8240 1004@end smallexample
c906108c
SS
1005
1006@noindent
2df3850c
JM
1007(which is ordinarily issued whenever a program running under
1008@value{GDBN} control terminates) is not issued when running in batch
1009mode.
1010
1a088d06
AS
1011@item -batch-silent
1012@cindex @code{--batch-silent}
1013Run in batch mode exactly like @samp{-batch}, but totally silently. All
1014@value{GDBN} output to @code{stdout} is prevented (@code{stderr} is
1015unaffected). This is much quieter than @samp{-silent} and would be useless
1016for an interactive session.
1017
1018This is particularly useful when using targets that give @samp{Loading section}
1019messages, for example.
1020
1021Note that targets that give their output via @value{GDBN}, as opposed to
1022writing directly to @code{stdout}, will also be made silent.
1023
4b0ad762
AS
1024@item -return-child-result
1025@cindex @code{--return-child-result}
1026The return code from @value{GDBN} will be the return code from the child
1027process (the process being debugged), with the following exceptions:
1028
1029@itemize @bullet
1030@item
1031@value{GDBN} exits abnormally. E.g., due to an incorrect argument or an
1032internal error. In this case the exit code is the same as it would have been
1033without @samp{-return-child-result}.
1034@item
1035The user quits with an explicit value. E.g., @samp{quit 1}.
1036@item
1037The child process never runs, or is not allowed to terminate, in which case
1038the exit code will be -1.
1039@end itemize
1040
1041This option is useful in conjunction with @samp{-batch} or @samp{-batch-silent},
1042when @value{GDBN} is being used as a remote program loader or simulator
1043interface.
1044
2df3850c
JM
1045@item -nowindows
1046@itemx -nw
d700128c
EZ
1047@cindex @code{--nowindows}
1048@cindex @code{-nw}
2df3850c 1049``No windows''. If @value{GDBN} comes with a graphical user interface
96a2c332 1050(GUI) built in, then this option tells @value{GDBN} to only use the command-line
2df3850c
JM
1051interface. If no GUI is available, this option has no effect.
1052
1053@item -windows
1054@itemx -w
d700128c
EZ
1055@cindex @code{--windows}
1056@cindex @code{-w}
2df3850c
JM
1057If @value{GDBN} includes a GUI, then this option requires it to be
1058used if possible.
c906108c
SS
1059
1060@item -cd @var{directory}
d700128c 1061@cindex @code{--cd}
c906108c
SS
1062Run @value{GDBN} using @var{directory} as its working directory,
1063instead of the current directory.
1064
c906108c
SS
1065@item -fullname
1066@itemx -f
d700128c
EZ
1067@cindex @code{--fullname}
1068@cindex @code{-f}
7a292a7a
SS
1069@sc{gnu} Emacs sets this option when it runs @value{GDBN} as a
1070subprocess. It tells @value{GDBN} to output the full file name and line
1071number in a standard, recognizable fashion each time a stack frame is
1072displayed (which includes each time your program stops). This
1073recognizable format looks like two @samp{\032} characters, followed by
1074the file name, line number and character position separated by colons,
1075and a newline. The Emacs-to-@value{GDBN} interface program uses the two
1076@samp{\032} characters as a signal to display the source code for the
1077frame.
c906108c 1078
d700128c
EZ
1079@item -epoch
1080@cindex @code{--epoch}
1081The Epoch Emacs-@value{GDBN} interface sets this option when it runs
1082@value{GDBN} as a subprocess. It tells @value{GDBN} to modify its print
1083routines so as to allow Epoch to display values of expressions in a
1084separate window.
1085
1086@item -annotate @var{level}
1087@cindex @code{--annotate}
1088This option sets the @dfn{annotation level} inside @value{GDBN}. Its
1089effect is identical to using @samp{set annotate @var{level}}
086432e2
AC
1090(@pxref{Annotations}). The annotation @var{level} controls how much
1091information @value{GDBN} prints together with its prompt, values of
1092expressions, source lines, and other types of output. Level 0 is the
1093normal, level 1 is for use when @value{GDBN} is run as a subprocess of
1094@sc{gnu} Emacs, level 3 is the maximum annotation suitable for programs
1095that control @value{GDBN}, and level 2 has been deprecated.
1096
265eeb58 1097The annotation mechanism has largely been superseded by @sc{gdb/mi}
086432e2 1098(@pxref{GDB/MI}).
d700128c 1099
aa26fa3a
TT
1100@item --args
1101@cindex @code{--args}
1102Change interpretation of command line so that arguments following the
1103executable file are passed as command line arguments to the inferior.
1104This option stops option processing.
1105
2df3850c
JM
1106@item -baud @var{bps}
1107@itemx -b @var{bps}
d700128c
EZ
1108@cindex @code{--baud}
1109@cindex @code{-b}
c906108c
SS
1110Set the line speed (baud rate or bits per second) of any serial
1111interface used by @value{GDBN} for remote debugging.
c906108c 1112
f47b1503
AS
1113@item -l @var{timeout}
1114@cindex @code{-l}
1115Set the timeout (in seconds) of any communication used by @value{GDBN}
1116for remote debugging.
1117
c906108c 1118@item -tty @var{device}
d700128c
EZ
1119@itemx -t @var{device}
1120@cindex @code{--tty}
1121@cindex @code{-t}
c906108c
SS
1122Run using @var{device} for your program's standard input and output.
1123@c FIXME: kingdon thinks there is more to -tty. Investigate.
c906108c 1124
53a5351d 1125@c resolve the situation of these eventually
c4555f82
SC
1126@item -tui
1127@cindex @code{--tui}
d0d5df6f
AC
1128Activate the @dfn{Text User Interface} when starting. The Text User
1129Interface manages several text windows on the terminal, showing
1130source, assembly, registers and @value{GDBN} command outputs
1131(@pxref{TUI, ,@value{GDBN} Text User Interface}). Alternatively, the
1132Text User Interface can be enabled by invoking the program
1133@samp{gdbtui}. Do not use this option if you run @value{GDBN} from
1134Emacs (@pxref{Emacs, ,Using @value{GDBN} under @sc{gnu} Emacs}).
53a5351d
JM
1135
1136@c @item -xdb
d700128c 1137@c @cindex @code{--xdb}
53a5351d
JM
1138@c Run in XDB compatibility mode, allowing the use of certain XDB commands.
1139@c For information, see the file @file{xdb_trans.html}, which is usually
1140@c installed in the directory @code{/opt/langtools/wdb/doc} on HP-UX
1141@c systems.
1142
d700128c
EZ
1143@item -interpreter @var{interp}
1144@cindex @code{--interpreter}
1145Use the interpreter @var{interp} for interface with the controlling
1146program or device. This option is meant to be set by programs which
94bbb2c0 1147communicate with @value{GDBN} using it as a back end.
21c294e6 1148@xref{Interpreters, , Command Interpreters}.
94bbb2c0 1149
da0f9dcd 1150@samp{--interpreter=mi} (or @samp{--interpreter=mi2}) causes
2fcf52f0 1151@value{GDBN} to use the @dfn{@sc{gdb/mi} interface} (@pxref{GDB/MI, ,
6b5e8c01 1152The @sc{gdb/mi} Interface}) included since @value{GDBN} version 6.0. The
6c74ac8b
AC
1153previous @sc{gdb/mi} interface, included in @value{GDBN} version 5.3 and
1154selected with @samp{--interpreter=mi1}, is deprecated. Earlier
1155@sc{gdb/mi} interfaces are no longer supported.
d700128c
EZ
1156
1157@item -write
1158@cindex @code{--write}
1159Open the executable and core files for both reading and writing. This
1160is equivalent to the @samp{set write on} command inside @value{GDBN}
1161(@pxref{Patching}).
1162
1163@item -statistics
1164@cindex @code{--statistics}
1165This option causes @value{GDBN} to print statistics about time and
1166memory usage after it completes each command and returns to the prompt.
1167
1168@item -version
1169@cindex @code{--version}
1170This option causes @value{GDBN} to print its version number and
1171no-warranty blurb, and exit.
1172
c906108c
SS
1173@end table
1174
6fc08d32
EZ
1175@node Startup
1176@subsection What @value{GDBN} does during startup
1177@cindex @value{GDBN} startup
1178
1179Here's the description of what @value{GDBN} does during session startup:
1180
1181@enumerate
1182@item
1183Sets up the command interpreter as specified by the command line
1184(@pxref{Mode Options, interpreter}).
1185
1186@item
1187@cindex init file
1188Reads the @dfn{init file} (if any) in your home directory@footnote{On
1189DOS/Windows systems, the home directory is the one pointed to by the
1190@code{HOME} environment variable.} and executes all the commands in
1191that file.
1192
1193@item
1194Processes command line options and operands.
1195
1196@item
1197Reads and executes the commands from init file (if any) in the current
119b882a
EZ
1198working directory. This is only done if the current directory is
1199different from your home directory. Thus, you can have more than one
1200init file, one generic in your home directory, and another, specific
1201to the program you are debugging, in the directory where you invoke
6fc08d32
EZ
1202@value{GDBN}.
1203
1204@item
1205Reads command files specified by the @samp{-x} option. @xref{Command
1206Files}, for more details about @value{GDBN} command files.
1207
1208@item
1209Reads the command history recorded in the @dfn{history file}.
d620b259 1210@xref{Command History}, for more details about the command history and the
6fc08d32
EZ
1211files where @value{GDBN} records it.
1212@end enumerate
1213
1214Init files use the same syntax as @dfn{command files} (@pxref{Command
1215Files}) and are processed by @value{GDBN} in the same way. The init
1216file in your home directory can set options (such as @samp{set
1217complaints}) that affect subsequent processing of command line options
1218and operands. Init files are not executed if you use the @samp{-nx}
1219option (@pxref{Mode Options, ,Choosing modes}).
1220
1221@cindex init file name
1222@cindex @file{.gdbinit}
119b882a 1223The @value{GDBN} init files are normally called @file{.gdbinit}.
6fc08d32
EZ
1224On some configurations of @value{GDBN}, the init file is known by a
1225different name (these are typically environments where a specialized
1226form of @value{GDBN} may need to coexist with other forms, hence a
1227different name for the specialized version's init file). These are the
1228environments with special init file names:
1229
6fc08d32 1230@itemize @bullet
119b882a
EZ
1231@cindex @file{gdb.ini}
1232@item
1233The DJGPP port of @value{GDBN} uses the name @file{gdb.ini}, due to
1234the limitations of file names imposed by DOS filesystems. The Windows
1235ports of @value{GDBN} use the standard name, but if they find a
1236@file{gdb.ini} file, they warn you about that and suggest to rename
1237the file to the standard name.
1238
1239@cindex @file{.vxgdbinit}
6fc08d32
EZ
1240@item
1241VxWorks (Wind River Systems real-time OS): @file{.vxgdbinit}
1242
1243@cindex @file{.os68gdbinit}
1244@item
1245OS68K (Enea Data Systems real-time OS): @file{.os68gdbinit}
1246
1247@cindex @file{.esgdbinit}
1248@item
1249ES-1800 (Ericsson Telecom AB M68000 emulator): @file{.esgdbinit}
1250
1251@item
1252CISCO 68k: @file{.cisco-gdbinit}
1253@end itemize
1254
1255
6d2ebf8b 1256@node Quitting GDB
c906108c
SS
1257@section Quitting @value{GDBN}
1258@cindex exiting @value{GDBN}
1259@cindex leaving @value{GDBN}
1260
1261@table @code
1262@kindex quit @r{[}@var{expression}@r{]}
41afff9a 1263@kindex q @r{(@code{quit})}
96a2c332
SS
1264@item quit @r{[}@var{expression}@r{]}
1265@itemx q
1266To exit @value{GDBN}, use the @code{quit} command (abbreviated
1267@code{q}), or type an end-of-file character (usually @kbd{C-d}). If you
1268do not supply @var{expression}, @value{GDBN} will terminate normally;
1269otherwise it will terminate using the result of @var{expression} as the
1270error code.
c906108c
SS
1271@end table
1272
1273@cindex interrupt
1274An interrupt (often @kbd{C-c}) does not exit from @value{GDBN}, but rather
1275terminates the action of any @value{GDBN} command that is in progress and
1276returns to @value{GDBN} command level. It is safe to type the interrupt
1277character at any time because @value{GDBN} does not allow it to take effect
1278until a time when it is safe.
1279
c906108c
SS
1280If you have been using @value{GDBN} to control an attached process or
1281device, you can release it with the @code{detach} command
1282(@pxref{Attach, ,Debugging an already-running process}).
c906108c 1283
6d2ebf8b 1284@node Shell Commands
c906108c
SS
1285@section Shell commands
1286
1287If you need to execute occasional shell commands during your
1288debugging session, there is no need to leave or suspend @value{GDBN}; you can
1289just use the @code{shell} command.
1290
1291@table @code
1292@kindex shell
1293@cindex shell escape
1294@item shell @var{command string}
1295Invoke a standard shell to execute @var{command string}.
c906108c 1296If it exists, the environment variable @code{SHELL} determines which
d4f3574e
SS
1297shell to run. Otherwise @value{GDBN} uses the default shell
1298(@file{/bin/sh} on Unix systems, @file{COMMAND.COM} on MS-DOS, etc.).
c906108c
SS
1299@end table
1300
1301The utility @code{make} is often needed in development environments.
1302You do not have to use the @code{shell} command for this purpose in
1303@value{GDBN}:
1304
1305@table @code
1306@kindex make
1307@cindex calling make
1308@item make @var{make-args}
1309Execute the @code{make} program with the specified
1310arguments. This is equivalent to @samp{shell make @var{make-args}}.
1311@end table
1312
0fac0b41
DJ
1313@node Logging output
1314@section Logging output
1315@cindex logging @value{GDBN} output
9c16f35a 1316@cindex save @value{GDBN} output to a file
0fac0b41
DJ
1317
1318You may want to save the output of @value{GDBN} commands to a file.
1319There are several commands to control @value{GDBN}'s logging.
1320
1321@table @code
1322@kindex set logging
1323@item set logging on
1324Enable logging.
1325@item set logging off
1326Disable logging.
9c16f35a 1327@cindex logging file name
0fac0b41
DJ
1328@item set logging file @var{file}
1329Change the name of the current logfile. The default logfile is @file{gdb.txt}.
1330@item set logging overwrite [on|off]
1331By default, @value{GDBN} will append to the logfile. Set @code{overwrite} if
1332you want @code{set logging on} to overwrite the logfile instead.
1333@item set logging redirect [on|off]
1334By default, @value{GDBN} output will go to both the terminal and the logfile.
1335Set @code{redirect} if you want output to go only to the log file.
1336@kindex show logging
1337@item show logging
1338Show the current values of the logging settings.
1339@end table
1340
6d2ebf8b 1341@node Commands
c906108c
SS
1342@chapter @value{GDBN} Commands
1343
1344You can abbreviate a @value{GDBN} command to the first few letters of the command
1345name, if that abbreviation is unambiguous; and you can repeat certain
1346@value{GDBN} commands by typing just @key{RET}. You can also use the @key{TAB}
1347key to get @value{GDBN} to fill out the rest of a word in a command (or to
1348show you the alternatives available, if there is more than one possibility).
1349
1350@menu
1351* Command Syntax:: How to give commands to @value{GDBN}
1352* Completion:: Command completion
1353* Help:: How to ask @value{GDBN} for help
1354@end menu
1355
6d2ebf8b 1356@node Command Syntax
c906108c
SS
1357@section Command syntax
1358
1359A @value{GDBN} command is a single line of input. There is no limit on
1360how long it can be. It starts with a command name, which is followed by
1361arguments whose meaning depends on the command name. For example, the
1362command @code{step} accepts an argument which is the number of times to
1363step, as in @samp{step 5}. You can also use the @code{step} command
96a2c332 1364with no arguments. Some commands do not allow any arguments.
c906108c
SS
1365
1366@cindex abbreviation
1367@value{GDBN} command names may always be truncated if that abbreviation is
1368unambiguous. Other possible command abbreviations are listed in the
1369documentation for individual commands. In some cases, even ambiguous
1370abbreviations are allowed; for example, @code{s} is specially defined as
1371equivalent to @code{step} even though there are other commands whose
1372names start with @code{s}. You can test abbreviations by using them as
1373arguments to the @code{help} command.
1374
1375@cindex repeating commands
41afff9a 1376@kindex RET @r{(repeat last command)}
c906108c 1377A blank line as input to @value{GDBN} (typing just @key{RET}) means to
96a2c332 1378repeat the previous command. Certain commands (for example, @code{run})
c906108c
SS
1379will not repeat this way; these are commands whose unintentional
1380repetition might cause trouble and which you are unlikely to want to
c45da7e6
EZ
1381repeat. User-defined commands can disable this feature; see
1382@ref{Define, dont-repeat}.
c906108c
SS
1383
1384The @code{list} and @code{x} commands, when you repeat them with
1385@key{RET}, construct new arguments rather than repeating
1386exactly as typed. This permits easy scanning of source or memory.
1387
1388@value{GDBN} can also use @key{RET} in another way: to partition lengthy
1389output, in a way similar to the common utility @code{more}
1390(@pxref{Screen Size,,Screen size}). Since it is easy to press one
1391@key{RET} too many in this situation, @value{GDBN} disables command
1392repetition after any command that generates this sort of display.
1393
41afff9a 1394@kindex # @r{(a comment)}
c906108c
SS
1395@cindex comment
1396Any text from a @kbd{#} to the end of the line is a comment; it does
1397nothing. This is useful mainly in command files (@pxref{Command
1398Files,,Command files}).
1399
88118b3a
TT
1400@cindex repeating command sequences
1401@kindex C-o @r{(operate-and-get-next)}
1402The @kbd{C-o} binding is useful for repeating a complex sequence of
1403commands. This command accepts the current line, like @kbd{RET}, and
1404then fetches the next line relative to the current line from the history
1405for editing.
1406
6d2ebf8b 1407@node Completion
c906108c
SS
1408@section Command completion
1409
1410@cindex completion
1411@cindex word completion
1412@value{GDBN} can fill in the rest of a word in a command for you, if there is
1413only one possibility; it can also show you what the valid possibilities
1414are for the next word in a command, at any time. This works for @value{GDBN}
1415commands, @value{GDBN} subcommands, and the names of symbols in your program.
1416
1417Press the @key{TAB} key whenever you want @value{GDBN} to fill out the rest
1418of a word. If there is only one possibility, @value{GDBN} fills in the
1419word, and waits for you to finish the command (or press @key{RET} to
1420enter it). For example, if you type
1421
1422@c FIXME "@key" does not distinguish its argument sufficiently to permit
1423@c complete accuracy in these examples; space introduced for clarity.
1424@c If texinfo enhancements make it unnecessary, it would be nice to
1425@c replace " @key" by "@key" in the following...
474c8240 1426@smallexample
c906108c 1427(@value{GDBP}) info bre @key{TAB}
474c8240 1428@end smallexample
c906108c
SS
1429
1430@noindent
1431@value{GDBN} fills in the rest of the word @samp{breakpoints}, since that is
1432the only @code{info} subcommand beginning with @samp{bre}:
1433
474c8240 1434@smallexample
c906108c 1435(@value{GDBP}) info breakpoints
474c8240 1436@end smallexample
c906108c
SS
1437
1438@noindent
1439You can either press @key{RET} at this point, to run the @code{info
1440breakpoints} command, or backspace and enter something else, if
1441@samp{breakpoints} does not look like the command you expected. (If you
1442were sure you wanted @code{info breakpoints} in the first place, you
1443might as well just type @key{RET} immediately after @samp{info bre},
1444to exploit command abbreviations rather than command completion).
1445
1446If there is more than one possibility for the next word when you press
1447@key{TAB}, @value{GDBN} sounds a bell. You can either supply more
1448characters and try again, or just press @key{TAB} a second time;
1449@value{GDBN} displays all the possible completions for that word. For
1450example, you might want to set a breakpoint on a subroutine whose name
1451begins with @samp{make_}, but when you type @kbd{b make_@key{TAB}} @value{GDBN}
1452just sounds the bell. Typing @key{TAB} again displays all the
1453function names in your program that begin with those characters, for
1454example:
1455
474c8240 1456@smallexample
c906108c
SS
1457(@value{GDBP}) b make_ @key{TAB}
1458@exdent @value{GDBN} sounds bell; press @key{TAB} again, to see:
5d161b24
DB
1459make_a_section_from_file make_environ
1460make_abs_section make_function_type
1461make_blockvector make_pointer_type
1462make_cleanup make_reference_type
c906108c
SS
1463make_command make_symbol_completion_list
1464(@value{GDBP}) b make_
474c8240 1465@end smallexample
c906108c
SS
1466
1467@noindent
1468After displaying the available possibilities, @value{GDBN} copies your
1469partial input (@samp{b make_} in the example) so you can finish the
1470command.
1471
1472If you just want to see the list of alternatives in the first place, you
b37052ae 1473can press @kbd{M-?} rather than pressing @key{TAB} twice. @kbd{M-?}
7a292a7a 1474means @kbd{@key{META} ?}. You can type this either by holding down a
c906108c 1475key designated as the @key{META} shift on your keyboard (if there is
7a292a7a 1476one) while typing @kbd{?}, or as @key{ESC} followed by @kbd{?}.
c906108c
SS
1477
1478@cindex quotes in commands
1479@cindex completion of quoted strings
1480Sometimes the string you need, while logically a ``word'', may contain
7a292a7a
SS
1481parentheses or other characters that @value{GDBN} normally excludes from
1482its notion of a word. To permit word completion to work in this
1483situation, you may enclose words in @code{'} (single quote marks) in
1484@value{GDBN} commands.
c906108c 1485
c906108c 1486The most likely situation where you might need this is in typing the
b37052ae
EZ
1487name of a C@t{++} function. This is because C@t{++} allows function
1488overloading (multiple definitions of the same function, distinguished
1489by argument type). For example, when you want to set a breakpoint you
1490may need to distinguish whether you mean the version of @code{name}
1491that takes an @code{int} parameter, @code{name(int)}, or the version
1492that takes a @code{float} parameter, @code{name(float)}. To use the
1493word-completion facilities in this situation, type a single quote
1494@code{'} at the beginning of the function name. This alerts
1495@value{GDBN} that it may need to consider more information than usual
1496when you press @key{TAB} or @kbd{M-?} to request word completion:
c906108c 1497
474c8240 1498@smallexample
96a2c332 1499(@value{GDBP}) b 'bubble( @kbd{M-?}
c906108c
SS
1500bubble(double,double) bubble(int,int)
1501(@value{GDBP}) b 'bubble(
474c8240 1502@end smallexample
c906108c
SS
1503
1504In some cases, @value{GDBN} can tell that completing a name requires using
1505quotes. When this happens, @value{GDBN} inserts the quote for you (while
1506completing as much as it can) if you do not type the quote in the first
1507place:
1508
474c8240 1509@smallexample
c906108c
SS
1510(@value{GDBP}) b bub @key{TAB}
1511@exdent @value{GDBN} alters your input line to the following, and rings a bell:
1512(@value{GDBP}) b 'bubble(
474c8240 1513@end smallexample
c906108c
SS
1514
1515@noindent
1516In general, @value{GDBN} can tell that a quote is needed (and inserts it) if
1517you have not yet started typing the argument list when you ask for
1518completion on an overloaded symbol.
1519
d4f3574e 1520For more information about overloaded functions, see @ref{C plus plus
b37052ae 1521expressions, ,C@t{++} expressions}. You can use the command @code{set
c906108c 1522overload-resolution off} to disable overload resolution;
b37052ae 1523see @ref{Debugging C plus plus, ,@value{GDBN} features for C@t{++}}.
c906108c
SS
1524
1525
6d2ebf8b 1526@node Help
c906108c
SS
1527@section Getting help
1528@cindex online documentation
1529@kindex help
1530
5d161b24 1531You can always ask @value{GDBN} itself for information on its commands,
c906108c
SS
1532using the command @code{help}.
1533
1534@table @code
41afff9a 1535@kindex h @r{(@code{help})}
c906108c
SS
1536@item help
1537@itemx h
1538You can use @code{help} (abbreviated @code{h}) with no arguments to
1539display a short list of named classes of commands:
1540
1541@smallexample
1542(@value{GDBP}) help
1543List of classes of commands:
1544
2df3850c 1545aliases -- Aliases of other commands
c906108c 1546breakpoints -- Making program stop at certain points
2df3850c 1547data -- Examining data
c906108c 1548files -- Specifying and examining files
2df3850c
JM
1549internals -- Maintenance commands
1550obscure -- Obscure features
1551running -- Running the program
1552stack -- Examining the stack
c906108c
SS
1553status -- Status inquiries
1554support -- Support facilities
96a2c332
SS
1555tracepoints -- Tracing of program execution without@*
1556 stopping the program
c906108c 1557user-defined -- User-defined commands
c906108c 1558
5d161b24 1559Type "help" followed by a class name for a list of
c906108c 1560commands in that class.
5d161b24 1561Type "help" followed by command name for full
c906108c
SS
1562documentation.
1563Command name abbreviations are allowed if unambiguous.
1564(@value{GDBP})
1565@end smallexample
96a2c332 1566@c the above line break eliminates huge line overfull...
c906108c
SS
1567
1568@item help @var{class}
1569Using one of the general help classes as an argument, you can get a
1570list of the individual commands in that class. For example, here is the
1571help display for the class @code{status}:
1572
1573@smallexample
1574(@value{GDBP}) help status
1575Status inquiries.
1576
1577List of commands:
1578
1579@c Line break in "show" line falsifies real output, but needed
1580@c to fit in smallbook page size.
2df3850c
JM
1581info -- Generic command for showing things
1582 about the program being debugged
1583show -- Generic command for showing things
1584 about the debugger
c906108c 1585
5d161b24 1586Type "help" followed by command name for full
c906108c
SS
1587documentation.
1588Command name abbreviations are allowed if unambiguous.
1589(@value{GDBP})
1590@end smallexample
1591
1592@item help @var{command}
1593With a command name as @code{help} argument, @value{GDBN} displays a
1594short paragraph on how to use that command.
1595
6837a0a2
DB
1596@kindex apropos
1597@item apropos @var{args}
09d4efe1 1598The @code{apropos} command searches through all of the @value{GDBN}
6837a0a2
DB
1599commands, and their documentation, for the regular expression specified in
1600@var{args}. It prints out all matches found. For example:
1601
1602@smallexample
1603apropos reload
1604@end smallexample
1605
b37052ae
EZ
1606@noindent
1607results in:
6837a0a2
DB
1608
1609@smallexample
6d2ebf8b
SS
1610@c @group
1611set symbol-reloading -- Set dynamic symbol table reloading
1612 multiple times in one run
1613show symbol-reloading -- Show dynamic symbol table reloading
1614 multiple times in one run
1615@c @end group
6837a0a2
DB
1616@end smallexample
1617
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SS
1618@kindex complete
1619@item complete @var{args}
1620The @code{complete @var{args}} command lists all the possible completions
1621for the beginning of a command. Use @var{args} to specify the beginning of the
1622command you want completed. For example:
1623
1624@smallexample
1625complete i
1626@end smallexample
1627
1628@noindent results in:
1629
1630@smallexample
1631@group
2df3850c
JM
1632if
1633ignore
c906108c
SS
1634info
1635inspect
c906108c
SS
1636@end group
1637@end smallexample
1638
1639@noindent This is intended for use by @sc{gnu} Emacs.
1640@end table
1641
1642In addition to @code{help}, you can use the @value{GDBN} commands @code{info}
1643and @code{show} to inquire about the state of your program, or the state
1644of @value{GDBN} itself. Each command supports many topics of inquiry; this
1645manual introduces each of them in the appropriate context. The listings
1646under @code{info} and under @code{show} in the Index point to
1647all the sub-commands. @xref{Index}.
1648
1649@c @group
1650@table @code
1651@kindex info
41afff9a 1652@kindex i @r{(@code{info})}
c906108c
SS
1653@item info
1654This command (abbreviated @code{i}) is for describing the state of your
1655program. For example, you can list the arguments given to your program
1656with @code{info args}, list the registers currently in use with @code{info
1657registers}, or list the breakpoints you have set with @code{info breakpoints}.
1658You can get a complete list of the @code{info} sub-commands with
1659@w{@code{help info}}.
1660
1661@kindex set
1662@item set
5d161b24 1663You can assign the result of an expression to an environment variable with
c906108c
SS
1664@code{set}. For example, you can set the @value{GDBN} prompt to a $-sign with
1665@code{set prompt $}.
1666
1667@kindex show
1668@item show
5d161b24 1669In contrast to @code{info}, @code{show} is for describing the state of
c906108c
SS
1670@value{GDBN} itself.
1671You can change most of the things you can @code{show}, by using the
1672related command @code{set}; for example, you can control what number
1673system is used for displays with @code{set radix}, or simply inquire
1674which is currently in use with @code{show radix}.
1675
1676@kindex info set
1677To display all the settable parameters and their current
1678values, you can use @code{show} with no arguments; you may also use
1679@code{info set}. Both commands produce the same display.
1680@c FIXME: "info set" violates the rule that "info" is for state of
1681@c FIXME...program. Ck w/ GNU: "info set" to be called something else,
1682@c FIXME...or change desc of rule---eg "state of prog and debugging session"?
1683@end table
1684@c @end group
1685
1686Here are three miscellaneous @code{show} subcommands, all of which are
1687exceptional in lacking corresponding @code{set} commands:
1688
1689@table @code
1690@kindex show version
9c16f35a 1691@cindex @value{GDBN} version number
c906108c
SS
1692@item show version
1693Show what version of @value{GDBN} is running. You should include this
2df3850c
JM
1694information in @value{GDBN} bug-reports. If multiple versions of
1695@value{GDBN} are in use at your site, you may need to determine which
1696version of @value{GDBN} you are running; as @value{GDBN} evolves, new
1697commands are introduced, and old ones may wither away. Also, many
1698system vendors ship variant versions of @value{GDBN}, and there are
96a2c332 1699variant versions of @value{GDBN} in @sc{gnu}/Linux distributions as well.
2df3850c
JM
1700The version number is the same as the one announced when you start
1701@value{GDBN}.
c906108c
SS
1702
1703@kindex show copying
09d4efe1 1704@kindex info copying
9c16f35a 1705@cindex display @value{GDBN} copyright
c906108c 1706@item show copying
09d4efe1 1707@itemx info copying
c906108c
SS
1708Display information about permission for copying @value{GDBN}.
1709
1710@kindex show warranty
09d4efe1 1711@kindex info warranty
c906108c 1712@item show warranty
09d4efe1 1713@itemx info warranty
2df3850c 1714Display the @sc{gnu} ``NO WARRANTY'' statement, or a warranty,
96a2c332 1715if your version of @value{GDBN} comes with one.
2df3850c 1716
c906108c
SS
1717@end table
1718
6d2ebf8b 1719@node Running
c906108c
SS
1720@chapter Running Programs Under @value{GDBN}
1721
1722When you run a program under @value{GDBN}, you must first generate
1723debugging information when you compile it.
7a292a7a
SS
1724
1725You may start @value{GDBN} with its arguments, if any, in an environment
1726of your choice. If you are doing native debugging, you may redirect
1727your program's input and output, debug an already running process, or
1728kill a child process.
c906108c
SS
1729
1730@menu
1731* Compilation:: Compiling for debugging
1732* Starting:: Starting your program
c906108c
SS
1733* Arguments:: Your program's arguments
1734* Environment:: Your program's environment
c906108c
SS
1735
1736* Working Directory:: Your program's working directory
1737* Input/Output:: Your program's input and output
1738* Attach:: Debugging an already-running process
1739* Kill Process:: Killing the child process
c906108c
SS
1740
1741* Threads:: Debugging programs with multiple threads
1742* Processes:: Debugging programs with multiple processes
5c95884b 1743* Checkpoint/Restart:: Setting a @emph{bookmark} to return to later
c906108c
SS
1744@end menu
1745
6d2ebf8b 1746@node Compilation
c906108c
SS
1747@section Compiling for debugging
1748
1749In order to debug a program effectively, you need to generate
1750debugging information when you compile it. This debugging information
1751is stored in the object file; it describes the data type of each
1752variable or function and the correspondence between source line numbers
1753and addresses in the executable code.
1754
1755To request debugging information, specify the @samp{-g} option when you run
1756the compiler.
1757
514c4d71
EZ
1758Programs that are to be shipped to your customers are compiled with
1759optimizations, using the @samp{-O} compiler option. However, many
1760compilers are unable to handle the @samp{-g} and @samp{-O} options
1761together. Using those compilers, you cannot generate optimized
c906108c
SS
1762executables containing debugging information.
1763
514c4d71 1764@value{NGCC}, the @sc{gnu} C/C@t{++} compiler, supports @samp{-g} with or
53a5351d
JM
1765without @samp{-O}, making it possible to debug optimized code. We
1766recommend that you @emph{always} use @samp{-g} whenever you compile a
1767program. You may think your program is correct, but there is no sense
1768in pushing your luck.
c906108c
SS
1769
1770@cindex optimized code, debugging
1771@cindex debugging optimized code
1772When you debug a program compiled with @samp{-g -O}, remember that the
1773optimizer is rearranging your code; the debugger shows you what is
1774really there. Do not be too surprised when the execution path does not
1775exactly match your source file! An extreme example: if you define a
1776variable, but never use it, @value{GDBN} never sees that
1777variable---because the compiler optimizes it out of existence.
1778
1779Some things do not work as well with @samp{-g -O} as with just
1780@samp{-g}, particularly on machines with instruction scheduling. If in
1781doubt, recompile with @samp{-g} alone, and if this fixes the problem,
1782please report it to us as a bug (including a test case!).
15387254 1783@xref{Variables}, for more information about debugging optimized code.
c906108c
SS
1784
1785Older versions of the @sc{gnu} C compiler permitted a variant option
1786@w{@samp{-gg}} for debugging information. @value{GDBN} no longer supports this
1787format; if your @sc{gnu} C compiler has this option, do not use it.
1788
514c4d71
EZ
1789@value{GDBN} knows about preprocessor macros and can show you their
1790expansion (@pxref{Macros}). Most compilers do not include information
1791about preprocessor macros in the debugging information if you specify
1792the @option{-g} flag alone, because this information is rather large.
1793Version 3.1 and later of @value{NGCC}, the @sc{gnu} C compiler,
1794provides macro information if you specify the options
1795@option{-gdwarf-2} and @option{-g3}; the former option requests
1796debugging information in the Dwarf 2 format, and the latter requests
1797``extra information''. In the future, we hope to find more compact
1798ways to represent macro information, so that it can be included with
1799@option{-g} alone.
1800
c906108c 1801@need 2000
6d2ebf8b 1802@node Starting
c906108c
SS
1803@section Starting your program
1804@cindex starting
1805@cindex running
1806
1807@table @code
1808@kindex run
41afff9a 1809@kindex r @r{(@code{run})}
c906108c
SS
1810@item run
1811@itemx r
7a292a7a
SS
1812Use the @code{run} command to start your program under @value{GDBN}.
1813You must first specify the program name (except on VxWorks) with an
1814argument to @value{GDBN} (@pxref{Invocation, ,Getting In and Out of
1815@value{GDBN}}), or by using the @code{file} or @code{exec-file} command
1816(@pxref{Files, ,Commands to specify files}).
c906108c
SS
1817
1818@end table
1819
c906108c
SS
1820If you are running your program in an execution environment that
1821supports processes, @code{run} creates an inferior process and makes
1822that process run your program. (In environments without processes,
1823@code{run} jumps to the start of your program.)
1824
1825The execution of a program is affected by certain information it
1826receives from its superior. @value{GDBN} provides ways to specify this
1827information, which you must do @emph{before} starting your program. (You
1828can change it after starting your program, but such changes only affect
1829your program the next time you start it.) This information may be
1830divided into four categories:
1831
1832@table @asis
1833@item The @emph{arguments.}
1834Specify the arguments to give your program as the arguments of the
1835@code{run} command. If a shell is available on your target, the shell
1836is used to pass the arguments, so that you may use normal conventions
1837(such as wildcard expansion or variable substitution) in describing
1838the arguments.
1839In Unix systems, you can control which shell is used with the
1840@code{SHELL} environment variable.
1841@xref{Arguments, ,Your program's arguments}.
1842
1843@item The @emph{environment.}
1844Your program normally inherits its environment from @value{GDBN}, but you can
1845use the @value{GDBN} commands @code{set environment} and @code{unset
1846environment} to change parts of the environment that affect
1847your program. @xref{Environment, ,Your program's environment}.
1848
1849@item The @emph{working directory.}
1850Your program inherits its working directory from @value{GDBN}. You can set
1851the @value{GDBN} working directory with the @code{cd} command in @value{GDBN}.
1852@xref{Working Directory, ,Your program's working directory}.
1853
1854@item The @emph{standard input and output.}
1855Your program normally uses the same device for standard input and
1856standard output as @value{GDBN} is using. You can redirect input and output
1857in the @code{run} command line, or you can use the @code{tty} command to
1858set a different device for your program.
1859@xref{Input/Output, ,Your program's input and output}.
1860
1861@cindex pipes
1862@emph{Warning:} While input and output redirection work, you cannot use
1863pipes to pass the output of the program you are debugging to another
1864program; if you attempt this, @value{GDBN} is likely to wind up debugging the
1865wrong program.
1866@end table
c906108c
SS
1867
1868When you issue the @code{run} command, your program begins to execute
1869immediately. @xref{Stopping, ,Stopping and continuing}, for discussion
1870of how to arrange for your program to stop. Once your program has
1871stopped, you may call functions in your program, using the @code{print}
1872or @code{call} commands. @xref{Data, ,Examining Data}.
1873
1874If the modification time of your symbol file has changed since the last
1875time @value{GDBN} read its symbols, @value{GDBN} discards its symbol
1876table, and reads it again. When it does this, @value{GDBN} tries to retain
1877your current breakpoints.
1878
4e8b0763
JB
1879@table @code
1880@kindex start
1881@item start
1882@cindex run to main procedure
1883The name of the main procedure can vary from language to language.
1884With C or C@t{++}, the main procedure name is always @code{main}, but
1885other languages such as Ada do not require a specific name for their
1886main procedure. The debugger provides a convenient way to start the
1887execution of the program and to stop at the beginning of the main
1888procedure, depending on the language used.
1889
1890The @samp{start} command does the equivalent of setting a temporary
1891breakpoint at the beginning of the main procedure and then invoking
1892the @samp{run} command.
1893
f018e82f
EZ
1894@cindex elaboration phase
1895Some programs contain an @dfn{elaboration} phase where some startup code is
1896executed before the main procedure is called. This depends on the
1897languages used to write your program. In C@t{++}, for instance,
4e8b0763
JB
1898constructors for static and global objects are executed before
1899@code{main} is called. It is therefore possible that the debugger stops
1900before reaching the main procedure. However, the temporary breakpoint
1901will remain to halt execution.
1902
1903Specify the arguments to give to your program as arguments to the
1904@samp{start} command. These arguments will be given verbatim to the
1905underlying @samp{run} command. Note that the same arguments will be
1906reused if no argument is provided during subsequent calls to
1907@samp{start} or @samp{run}.
1908
1909It is sometimes necessary to debug the program during elaboration. In
1910these cases, using the @code{start} command would stop the execution of
1911your program too late, as the program would have already completed the
1912elaboration phase. Under these circumstances, insert breakpoints in your
1913elaboration code before running your program.
1914@end table
1915
6d2ebf8b 1916@node Arguments
c906108c
SS
1917@section Your program's arguments
1918
1919@cindex arguments (to your program)
1920The arguments to your program can be specified by the arguments of the
5d161b24 1921@code{run} command.
c906108c
SS
1922They are passed to a shell, which expands wildcard characters and
1923performs redirection of I/O, and thence to your program. Your
1924@code{SHELL} environment variable (if it exists) specifies what shell
1925@value{GDBN} uses. If you do not define @code{SHELL}, @value{GDBN} uses
d4f3574e
SS
1926the default shell (@file{/bin/sh} on Unix).
1927
1928On non-Unix systems, the program is usually invoked directly by
1929@value{GDBN}, which emulates I/O redirection via the appropriate system
1930calls, and the wildcard characters are expanded by the startup code of
1931the program, not by the shell.
c906108c
SS
1932
1933@code{run} with no arguments uses the same arguments used by the previous
1934@code{run}, or those set by the @code{set args} command.
1935
c906108c 1936@table @code
41afff9a 1937@kindex set args
c906108c
SS
1938@item set args
1939Specify the arguments to be used the next time your program is run. If
1940@code{set args} has no arguments, @code{run} executes your program
1941with no arguments. Once you have run your program with arguments,
1942using @code{set args} before the next @code{run} is the only way to run
1943it again without arguments.
1944
1945@kindex show args
1946@item show args
1947Show the arguments to give your program when it is started.
1948@end table
1949
6d2ebf8b 1950@node Environment
c906108c
SS
1951@section Your program's environment
1952
1953@cindex environment (of your program)
1954The @dfn{environment} consists of a set of environment variables and
1955their values. Environment variables conventionally record such things as
1956your user name, your home directory, your terminal type, and your search
1957path for programs to run. Usually you set up environment variables with
1958the shell and they are inherited by all the other programs you run. When
1959debugging, it can be useful to try running your program with a modified
1960environment without having to start @value{GDBN} over again.
1961
1962@table @code
1963@kindex path
1964@item path @var{directory}
1965Add @var{directory} to the front of the @code{PATH} environment variable
17cc6a06
EZ
1966(the search path for executables) that will be passed to your program.
1967The value of @code{PATH} used by @value{GDBN} does not change.
d4f3574e
SS
1968You may specify several directory names, separated by whitespace or by a
1969system-dependent separator character (@samp{:} on Unix, @samp{;} on
1970MS-DOS and MS-Windows). If @var{directory} is already in the path, it
1971is moved to the front, so it is searched sooner.
c906108c
SS
1972
1973You can use the string @samp{$cwd} to refer to whatever is the current
1974working directory at the time @value{GDBN} searches the path. If you
1975use @samp{.} instead, it refers to the directory where you executed the
1976@code{path} command. @value{GDBN} replaces @samp{.} in the
1977@var{directory} argument (with the current path) before adding
1978@var{directory} to the search path.
1979@c 'path' is explicitly nonrepeatable, but RMS points out it is silly to
1980@c document that, since repeating it would be a no-op.
1981
1982@kindex show paths
1983@item show paths
1984Display the list of search paths for executables (the @code{PATH}
1985environment variable).
1986
1987@kindex show environment
1988@item show environment @r{[}@var{varname}@r{]}
1989Print the value of environment variable @var{varname} to be given to
1990your program when it starts. If you do not supply @var{varname},
1991print the names and values of all environment variables to be given to
1992your program. You can abbreviate @code{environment} as @code{env}.
1993
1994@kindex set environment
53a5351d 1995@item set environment @var{varname} @r{[}=@var{value}@r{]}
c906108c
SS
1996Set environment variable @var{varname} to @var{value}. The value
1997changes for your program only, not for @value{GDBN} itself. @var{value} may
1998be any string; the values of environment variables are just strings, and
1999any interpretation is supplied by your program itself. The @var{value}
2000parameter is optional; if it is eliminated, the variable is set to a
2001null value.
2002@c "any string" here does not include leading, trailing
2003@c blanks. Gnu asks: does anyone care?
2004
2005For example, this command:
2006
474c8240 2007@smallexample
c906108c 2008set env USER = foo
474c8240 2009@end smallexample
c906108c
SS
2010
2011@noindent
d4f3574e 2012tells the debugged program, when subsequently run, that its user is named
c906108c
SS
2013@samp{foo}. (The spaces around @samp{=} are used for clarity here; they
2014are not actually required.)
2015
2016@kindex unset environment
2017@item unset environment @var{varname}
2018Remove variable @var{varname} from the environment to be passed to your
2019program. This is different from @samp{set env @var{varname} =};
2020@code{unset environment} removes the variable from the environment,
2021rather than assigning it an empty value.
2022@end table
2023
d4f3574e
SS
2024@emph{Warning:} On Unix systems, @value{GDBN} runs your program using
2025the shell indicated
c906108c
SS
2026by your @code{SHELL} environment variable if it exists (or
2027@code{/bin/sh} if not). If your @code{SHELL} variable names a shell
2028that runs an initialization file---such as @file{.cshrc} for C-shell, or
2029@file{.bashrc} for BASH---any variables you set in that file affect
2030your program. You may wish to move setting of environment variables to
2031files that are only run when you sign on, such as @file{.login} or
2032@file{.profile}.
2033
6d2ebf8b 2034@node Working Directory
c906108c
SS
2035@section Your program's working directory
2036
2037@cindex working directory (of your program)
2038Each time you start your program with @code{run}, it inherits its
2039working directory from the current working directory of @value{GDBN}.
2040The @value{GDBN} working directory is initially whatever it inherited
2041from its parent process (typically the shell), but you can specify a new
2042working directory in @value{GDBN} with the @code{cd} command.
2043
2044The @value{GDBN} working directory also serves as a default for the commands
2045that specify files for @value{GDBN} to operate on. @xref{Files, ,Commands to
2046specify files}.
2047
2048@table @code
2049@kindex cd
721c2651 2050@cindex change working directory
c906108c
SS
2051@item cd @var{directory}
2052Set the @value{GDBN} working directory to @var{directory}.
2053
2054@kindex pwd
2055@item pwd
2056Print the @value{GDBN} working directory.
2057@end table
2058
60bf7e09
EZ
2059It is generally impossible to find the current working directory of
2060the process being debugged (since a program can change its directory
2061during its run). If you work on a system where @value{GDBN} is
2062configured with the @file{/proc} support, you can use the @code{info
2063proc} command (@pxref{SVR4 Process Information}) to find out the
2064current working directory of the debuggee.
2065
6d2ebf8b 2066@node Input/Output
c906108c
SS
2067@section Your program's input and output
2068
2069@cindex redirection
2070@cindex i/o
2071@cindex terminal
2072By default, the program you run under @value{GDBN} does input and output to
5d161b24 2073the same terminal that @value{GDBN} uses. @value{GDBN} switches the terminal
c906108c
SS
2074to its own terminal modes to interact with you, but it records the terminal
2075modes your program was using and switches back to them when you continue
2076running your program.
2077
2078@table @code
2079@kindex info terminal
2080@item info terminal
2081Displays information recorded by @value{GDBN} about the terminal modes your
2082program is using.
2083@end table
2084
2085You can redirect your program's input and/or output using shell
2086redirection with the @code{run} command. For example,
2087
474c8240 2088@smallexample
c906108c 2089run > outfile
474c8240 2090@end smallexample
c906108c
SS
2091
2092@noindent
2093starts your program, diverting its output to the file @file{outfile}.
2094
2095@kindex tty
2096@cindex controlling terminal
2097Another way to specify where your program should do input and output is
2098with the @code{tty} command. This command accepts a file name as
2099argument, and causes this file to be the default for future @code{run}
2100commands. It also resets the controlling terminal for the child
2101process, for future @code{run} commands. For example,
2102
474c8240 2103@smallexample
c906108c 2104tty /dev/ttyb
474c8240 2105@end smallexample
c906108c
SS
2106
2107@noindent
2108directs that processes started with subsequent @code{run} commands
2109default to do input and output on the terminal @file{/dev/ttyb} and have
2110that as their controlling terminal.
2111
2112An explicit redirection in @code{run} overrides the @code{tty} command's
2113effect on the input/output device, but not its effect on the controlling
2114terminal.
2115
2116When you use the @code{tty} command or redirect input in the @code{run}
2117command, only the input @emph{for your program} is affected. The input
3cb3b8df
BR
2118for @value{GDBN} still comes from your terminal. @code{tty} is an alias
2119for @code{set inferior-tty}.
2120
2121@cindex inferior tty
2122@cindex set inferior controlling terminal
2123You can use the @code{show inferior-tty} command to tell @value{GDBN} to
2124display the name of the terminal that will be used for future runs of your
2125program.
2126
2127@table @code
2128@item set inferior-tty /dev/ttyb
2129@kindex set inferior-tty
2130Set the tty for the program being debugged to /dev/ttyb.
2131
2132@item show inferior-tty
2133@kindex show inferior-tty
2134Show the current tty for the program being debugged.
2135@end table
c906108c 2136
6d2ebf8b 2137@node Attach
c906108c
SS
2138@section Debugging an already-running process
2139@kindex attach
2140@cindex attach
2141
2142@table @code
2143@item attach @var{process-id}
2144This command attaches to a running process---one that was started
2145outside @value{GDBN}. (@code{info files} shows your active
2146targets.) The command takes as argument a process ID. The usual way to
09d4efe1 2147find out the @var{process-id} of a Unix process is with the @code{ps} utility,
c906108c
SS
2148or with the @samp{jobs -l} shell command.
2149
2150@code{attach} does not repeat if you press @key{RET} a second time after
2151executing the command.
2152@end table
2153
2154To use @code{attach}, your program must be running in an environment
2155which supports processes; for example, @code{attach} does not work for
2156programs on bare-board targets that lack an operating system. You must
2157also have permission to send the process a signal.
2158
2159When you use @code{attach}, the debugger finds the program running in
2160the process first by looking in the current working directory, then (if
2161the program is not found) by using the source file search path
2162(@pxref{Source Path, ,Specifying source directories}). You can also use
2163the @code{file} command to load the program. @xref{Files, ,Commands to
2164Specify Files}.
2165
2166The first thing @value{GDBN} does after arranging to debug the specified
2167process is to stop it. You can examine and modify an attached process
53a5351d
JM
2168with all the @value{GDBN} commands that are ordinarily available when
2169you start processes with @code{run}. You can insert breakpoints; you
2170can step and continue; you can modify storage. If you would rather the
2171process continue running, you may use the @code{continue} command after
c906108c
SS
2172attaching @value{GDBN} to the process.
2173
2174@table @code
2175@kindex detach
2176@item detach
2177When you have finished debugging the attached process, you can use the
2178@code{detach} command to release it from @value{GDBN} control. Detaching
2179the process continues its execution. After the @code{detach} command,
2180that process and @value{GDBN} become completely independent once more, and you
2181are ready to @code{attach} another process or start one with @code{run}.
2182@code{detach} does not repeat if you press @key{RET} again after
2183executing the command.
2184@end table
2185
2186If you exit @value{GDBN} or use the @code{run} command while you have an
2187attached process, you kill that process. By default, @value{GDBN} asks
2188for confirmation if you try to do either of these things; you can
2189control whether or not you need to confirm by using the @code{set
2190confirm} command (@pxref{Messages/Warnings, ,Optional warnings and
2191messages}).
2192
6d2ebf8b 2193@node Kill Process
c906108c 2194@section Killing the child process
c906108c
SS
2195
2196@table @code
2197@kindex kill
2198@item kill
2199Kill the child process in which your program is running under @value{GDBN}.
2200@end table
2201
2202This command is useful if you wish to debug a core dump instead of a
2203running process. @value{GDBN} ignores any core dump file while your program
2204is running.
2205
2206On some operating systems, a program cannot be executed outside @value{GDBN}
2207while you have breakpoints set on it inside @value{GDBN}. You can use the
2208@code{kill} command in this situation to permit running your program
2209outside the debugger.
2210
2211The @code{kill} command is also useful if you wish to recompile and
2212relink your program, since on many systems it is impossible to modify an
2213executable file while it is running in a process. In this case, when you
2214next type @code{run}, @value{GDBN} notices that the file has changed, and
2215reads the symbol table again (while trying to preserve your current
2216breakpoint settings).
2217
6d2ebf8b 2218@node Threads
c906108c 2219@section Debugging programs with multiple threads
c906108c
SS
2220
2221@cindex threads of execution
2222@cindex multiple threads
2223@cindex switching threads
2224In some operating systems, such as HP-UX and Solaris, a single program
2225may have more than one @dfn{thread} of execution. The precise semantics
2226of threads differ from one operating system to another, but in general
2227the threads of a single program are akin to multiple processes---except
2228that they share one address space (that is, they can all examine and
2229modify the same variables). On the other hand, each thread has its own
2230registers and execution stack, and perhaps private memory.
2231
2232@value{GDBN} provides these facilities for debugging multi-thread
2233programs:
2234
2235@itemize @bullet
2236@item automatic notification of new threads
2237@item @samp{thread @var{threadno}}, a command to switch among threads
2238@item @samp{info threads}, a command to inquire about existing threads
5d161b24 2239@item @samp{thread apply [@var{threadno}] [@var{all}] @var{args}},
c906108c
SS
2240a command to apply a command to a list of threads
2241@item thread-specific breakpoints
2242@end itemize
2243
c906108c
SS
2244@quotation
2245@emph{Warning:} These facilities are not yet available on every
2246@value{GDBN} configuration where the operating system supports threads.
2247If your @value{GDBN} does not support threads, these commands have no
2248effect. For example, a system without thread support shows no output
2249from @samp{info threads}, and always rejects the @code{thread} command,
2250like this:
2251
2252@smallexample
2253(@value{GDBP}) info threads
2254(@value{GDBP}) thread 1
2255Thread ID 1 not known. Use the "info threads" command to
2256see the IDs of currently known threads.
2257@end smallexample
2258@c FIXME to implementors: how hard would it be to say "sorry, this GDB
2259@c doesn't support threads"?
2260@end quotation
c906108c
SS
2261
2262@cindex focus of debugging
2263@cindex current thread
2264The @value{GDBN} thread debugging facility allows you to observe all
2265threads while your program runs---but whenever @value{GDBN} takes
2266control, one thread in particular is always the focus of debugging.
2267This thread is called the @dfn{current thread}. Debugging commands show
2268program information from the perspective of the current thread.
2269
41afff9a 2270@cindex @code{New} @var{systag} message
c906108c
SS
2271@cindex thread identifier (system)
2272@c FIXME-implementors!! It would be more helpful if the [New...] message
2273@c included GDB's numeric thread handle, so you could just go to that
2274@c thread without first checking `info threads'.
2275Whenever @value{GDBN} detects a new thread in your program, it displays
2276the target system's identification for the thread with a message in the
2277form @samp{[New @var{systag}]}. @var{systag} is a thread identifier
2278whose form varies depending on the particular system. For example, on
2279LynxOS, you might see
2280
474c8240 2281@smallexample
c906108c 2282[New process 35 thread 27]
474c8240 2283@end smallexample
c906108c
SS
2284
2285@noindent
2286when @value{GDBN} notices a new thread. In contrast, on an SGI system,
2287the @var{systag} is simply something like @samp{process 368}, with no
2288further qualifier.
2289
2290@c FIXME!! (1) Does the [New...] message appear even for the very first
2291@c thread of a program, or does it only appear for the
6ca652b0 2292@c second---i.e.@: when it becomes obvious we have a multithread
c906108c
SS
2293@c program?
2294@c (2) *Is* there necessarily a first thread always? Or do some
2295@c multithread systems permit starting a program with multiple
5d161b24 2296@c threads ab initio?
c906108c
SS
2297
2298@cindex thread number
2299@cindex thread identifier (GDB)
2300For debugging purposes, @value{GDBN} associates its own thread
2301number---always a single integer---with each thread in your program.
2302
2303@table @code
2304@kindex info threads
2305@item info threads
2306Display a summary of all threads currently in your
2307program. @value{GDBN} displays for each thread (in this order):
2308
2309@enumerate
09d4efe1
EZ
2310@item
2311the thread number assigned by @value{GDBN}
c906108c 2312
09d4efe1
EZ
2313@item
2314the target system's thread identifier (@var{systag})
c906108c 2315
09d4efe1
EZ
2316@item
2317the current stack frame summary for that thread
c906108c
SS
2318@end enumerate
2319
2320@noindent
2321An asterisk @samp{*} to the left of the @value{GDBN} thread number
2322indicates the current thread.
2323
5d161b24 2324For example,
c906108c
SS
2325@end table
2326@c end table here to get a little more width for example
2327
2328@smallexample
2329(@value{GDBP}) info threads
2330 3 process 35 thread 27 0x34e5 in sigpause ()
2331 2 process 35 thread 23 0x34e5 in sigpause ()
2332* 1 process 35 thread 13 main (argc=1, argv=0x7ffffff8)
2333 at threadtest.c:68
2334@end smallexample
53a5351d
JM
2335
2336On HP-UX systems:
c906108c 2337
4644b6e3
EZ
2338@cindex debugging multithreaded programs (on HP-UX)
2339@cindex thread identifier (GDB), on HP-UX
c906108c
SS
2340For debugging purposes, @value{GDBN} associates its own thread
2341number---a small integer assigned in thread-creation order---with each
2342thread in your program.
2343
41afff9a
EZ
2344@cindex @code{New} @var{systag} message, on HP-UX
2345@cindex thread identifier (system), on HP-UX
c906108c
SS
2346@c FIXME-implementors!! It would be more helpful if the [New...] message
2347@c included GDB's numeric thread handle, so you could just go to that
2348@c thread without first checking `info threads'.
2349Whenever @value{GDBN} detects a new thread in your program, it displays
2350both @value{GDBN}'s thread number and the target system's identification for the thread with a message in the
2351form @samp{[New @var{systag}]}. @var{systag} is a thread identifier
2352whose form varies depending on the particular system. For example, on
2353HP-UX, you see
2354
474c8240 2355@smallexample
c906108c 2356[New thread 2 (system thread 26594)]
474c8240 2357@end smallexample
c906108c
SS
2358
2359@noindent
5d161b24 2360when @value{GDBN} notices a new thread.
c906108c
SS
2361
2362@table @code
4644b6e3 2363@kindex info threads (HP-UX)
c906108c
SS
2364@item info threads
2365Display a summary of all threads currently in your
2366program. @value{GDBN} displays for each thread (in this order):
2367
2368@enumerate
2369@item the thread number assigned by @value{GDBN}
2370
2371@item the target system's thread identifier (@var{systag})
2372
2373@item the current stack frame summary for that thread
2374@end enumerate
2375
2376@noindent
2377An asterisk @samp{*} to the left of the @value{GDBN} thread number
2378indicates the current thread.
2379
5d161b24 2380For example,
c906108c
SS
2381@end table
2382@c end table here to get a little more width for example
2383
474c8240 2384@smallexample
c906108c 2385(@value{GDBP}) info threads
6d2ebf8b
SS
2386 * 3 system thread 26607 worker (wptr=0x7b09c318 "@@") \@*
2387 at quicksort.c:137
2388 2 system thread 26606 0x7b0030d8 in __ksleep () \@*
2389 from /usr/lib/libc.2
2390 1 system thread 27905 0x7b003498 in _brk () \@*
2391 from /usr/lib/libc.2
474c8240 2392@end smallexample
c906108c 2393
c45da7e6
EZ
2394On Solaris, you can display more information about user threads with a
2395Solaris-specific command:
2396
2397@table @code
2398@item maint info sol-threads
2399@kindex maint info sol-threads
2400@cindex thread info (Solaris)
2401Display info on Solaris user threads.
2402@end table
2403
c906108c
SS
2404@table @code
2405@kindex thread @var{threadno}
2406@item thread @var{threadno}
2407Make thread number @var{threadno} the current thread. The command
2408argument @var{threadno} is the internal @value{GDBN} thread number, as
2409shown in the first field of the @samp{info threads} display.
2410@value{GDBN} responds by displaying the system identifier of the thread
2411you selected, and its current stack frame summary:
2412
2413@smallexample
2414@c FIXME!! This example made up; find a @value{GDBN} w/threads and get real one
2415(@value{GDBP}) thread 2
c906108c 2416[Switching to process 35 thread 23]
c906108c
SS
24170x34e5 in sigpause ()
2418@end smallexample
2419
2420@noindent
2421As with the @samp{[New @dots{}]} message, the form of the text after
2422@samp{Switching to} depends on your system's conventions for identifying
5d161b24 2423threads.
c906108c 2424
9c16f35a 2425@kindex thread apply
638ac427 2426@cindex apply command to several threads
839c27b7
EZ
2427@item thread apply [@var{threadno}] [@var{all}] @var{command}
2428The @code{thread apply} command allows you to apply the named
2429@var{command} to one or more threads. Specify the numbers of the
2430threads that you want affected with the command argument
2431@var{threadno}. It can be a single thread number, one of the numbers
2432shown in the first field of the @samp{info threads} display; or it
2433could be a range of thread numbers, as in @code{2-4}. To apply a
2434command to all threads, type @kbd{thread apply all @var{command}}.
c906108c
SS
2435@end table
2436
2437@cindex automatic thread selection
2438@cindex switching threads automatically
2439@cindex threads, automatic switching
2440Whenever @value{GDBN} stops your program, due to a breakpoint or a
2441signal, it automatically selects the thread where that breakpoint or
2442signal happened. @value{GDBN} alerts you to the context switch with a
2443message of the form @samp{[Switching to @var{systag}]} to identify the
2444thread.
2445
2446@xref{Thread Stops,,Stopping and starting multi-thread programs}, for
2447more information about how @value{GDBN} behaves when you stop and start
2448programs with multiple threads.
2449
2450@xref{Set Watchpoints,,Setting watchpoints}, for information about
2451watchpoints in programs with multiple threads.
c906108c 2452
6d2ebf8b 2453@node Processes
c906108c
SS
2454@section Debugging programs with multiple processes
2455
2456@cindex fork, debugging programs which call
2457@cindex multiple processes
2458@cindex processes, multiple
53a5351d
JM
2459On most systems, @value{GDBN} has no special support for debugging
2460programs which create additional processes using the @code{fork}
2461function. When a program forks, @value{GDBN} will continue to debug the
2462parent process and the child process will run unimpeded. If you have
2463set a breakpoint in any code which the child then executes, the child
2464will get a @code{SIGTRAP} signal which (unless it catches the signal)
2465will cause it to terminate.
c906108c
SS
2466
2467However, if you want to debug the child process there is a workaround
2468which isn't too painful. Put a call to @code{sleep} in the code which
2469the child process executes after the fork. It may be useful to sleep
2470only if a certain environment variable is set, or a certain file exists,
2471so that the delay need not occur when you don't want to run @value{GDBN}
2472on the child. While the child is sleeping, use the @code{ps} program to
2473get its process ID. Then tell @value{GDBN} (a new invocation of
2474@value{GDBN} if you are also debugging the parent process) to attach to
d4f3574e 2475the child process (@pxref{Attach}). From that point on you can debug
c906108c 2476the child process just like any other process which you attached to.
c906108c 2477
b51970ac
DJ
2478On some systems, @value{GDBN} provides support for debugging programs that
2479create additional processes using the @code{fork} or @code{vfork} functions.
2480Currently, the only platforms with this feature are HP-UX (11.x and later
2481only?) and GNU/Linux (kernel version 2.5.60 and later).
c906108c
SS
2482
2483By default, when a program forks, @value{GDBN} will continue to debug
2484the parent process and the child process will run unimpeded.
2485
2486If you want to follow the child process instead of the parent process,
2487use the command @w{@code{set follow-fork-mode}}.
2488
2489@table @code
2490@kindex set follow-fork-mode
2491@item set follow-fork-mode @var{mode}
2492Set the debugger response to a program call of @code{fork} or
2493@code{vfork}. A call to @code{fork} or @code{vfork} creates a new
9c16f35a 2494process. The @var{mode} argument can be:
c906108c
SS
2495
2496@table @code
2497@item parent
2498The original process is debugged after a fork. The child process runs
2df3850c 2499unimpeded. This is the default.
c906108c
SS
2500
2501@item child
2502The new process is debugged after a fork. The parent process runs
2503unimpeded.
2504
c906108c
SS
2505@end table
2506
9c16f35a 2507@kindex show follow-fork-mode
c906108c 2508@item show follow-fork-mode
2df3850c 2509Display the current debugger response to a @code{fork} or @code{vfork} call.
c906108c
SS
2510@end table
2511
5c95884b
MS
2512@cindex debugging multiple processes
2513On Linux, if you want to debug both the parent and child processes, use the
2514command @w{@code{set detach-on-fork}}.
2515
2516@table @code
2517@kindex set detach-on-fork
2518@item set detach-on-fork @var{mode}
2519Tells gdb whether to detach one of the processes after a fork, or
2520retain debugger control over them both.
2521
2522@table @code
2523@item on
2524The child process (or parent process, depending on the value of
2525@code{follow-fork-mode}) will be detached and allowed to run
2526independently. This is the default.
2527
2528@item off
2529Both processes will be held under the control of @value{GDBN}.
2530One process (child or parent, depending on the value of
2531@code{follow-fork-mode}) is debugged as usual, while the other
2532is held suspended.
2533
2534@end table
2535
2536@kindex show detach-on-follow
2537@item show detach-on-follow
2538Show whether detach-on-follow mode is on/off.
2539@end table
2540
2541If you choose to set @var{detach-on-follow} mode off, then
2542@value{GDBN} will retain control of all forked processes (including
2543nested forks). You can list the forked processes under the control of
2544@value{GDBN} by using the @w{@code{info forks}} command, and switch
2545from one fork to another by using the @w{@code{fork}} command.
2546
2547@table @code
2548@kindex info forks
2549@item info forks
2550Print a list of all forked processes under the control of @value{GDBN}.
2551The listing will include a fork id, a process id, and the current
2552position (program counter) of the process.
2553
2554
2555@kindex fork @var{fork-id}
2556@item fork @var{fork-id}
2557Make fork number @var{fork-id} the current process. The argument
2558@var{fork-id} is the internal fork number assigned by @value{GDBN},
2559as shown in the first field of the @samp{info forks} display.
2560
2561@end table
2562
2563To quit debugging one of the forked processes, you can either detach
2564from it by using the @w{@code{detach-fork}} command (allowing it to
2565run independently), or delete (and kill) it using the
2566@w{@code{delete-fork}} command.
2567
2568@table @code
2569@kindex detach-fork @var{fork-id}
2570@item detach-fork @var{fork-id}
2571Detach from the process identified by @value{GDBN} fork number
2572@var{fork-id}, and remove it from the fork list. The process will be
2573allowed to run independently.
2574
2575@kindex delete-fork @var{fork-id}
2576@item delete-fork @var{fork-id}
2577Kill the process identified by @value{GDBN} fork number @var{fork-id},
2578and remove it from the fork list.
2579
2580@end table
2581
c906108c
SS
2582If you ask to debug a child process and a @code{vfork} is followed by an
2583@code{exec}, @value{GDBN} executes the new target up to the first
2584breakpoint in the new target. If you have a breakpoint set on
2585@code{main} in your original program, the breakpoint will also be set on
2586the child process's @code{main}.
2587
2588When a child process is spawned by @code{vfork}, you cannot debug the
2589child or parent until an @code{exec} call completes.
2590
2591If you issue a @code{run} command to @value{GDBN} after an @code{exec}
2592call executes, the new target restarts. To restart the parent process,
2593use the @code{file} command with the parent executable name as its
2594argument.
2595
2596You can use the @code{catch} command to make @value{GDBN} stop whenever
2597a @code{fork}, @code{vfork}, or @code{exec} call is made. @xref{Set
2598Catchpoints, ,Setting catchpoints}.
c906108c 2599
5c95884b
MS
2600@node Checkpoint/Restart
2601@section Setting a @emph{bookmark} to return to later
2602
2603@cindex checkpoint
2604@cindex restart
2605@cindex bookmark
2606@cindex snapshot of a process
2607@cindex rewind program state
2608
2609On certain operating systems@footnote{Currently, only
2610@sc{gnu}/Linux.}, @value{GDBN} is able to save a @dfn{snapshot} of a
2611program's state, called a @dfn{checkpoint}, and come back to it
2612later.
2613
2614Returning to a checkpoint effectively undoes everything that has
2615happened in the program since the @code{checkpoint} was saved. This
2616includes changes in memory, registers, and even (within some limits)
2617system state. Effectively, it is like going back in time to the
2618moment when the checkpoint was saved.
2619
2620Thus, if you're stepping thru a program and you think you're
2621getting close to the point where things go wrong, you can save
2622a checkpoint. Then, if you accidentally go too far and miss
2623the critical statement, instead of having to restart your program
2624from the beginning, you can just go back to the checkpoint and
2625start again from there.
2626
2627This can be especially useful if it takes a lot of time or
2628steps to reach the point where you think the bug occurs.
2629
2630To use the @code{checkpoint}/@code{restart} method of debugging:
2631
2632@table @code
2633@kindex checkpoint
2634@item checkpoint
2635Save a snapshot of the debugged program's current execution state.
2636The @code{checkpoint} command takes no arguments, but each checkpoint
2637is assigned a small integer id, similar to a breakpoint id.
2638
2639@kindex info checkpoints
2640@item info checkpoints
2641List the checkpoints that have been saved in the current debugging
2642session. For each checkpoint, the following information will be
2643listed:
2644
2645@table @code
2646@item Checkpoint ID
2647@item Process ID
2648@item Code Address
2649@item Source line, or label
2650@end table
2651
2652@kindex restart @var{checkpoint-id}
2653@item restart @var{checkpoint-id}
2654Restore the program state that was saved as checkpoint number
2655@var{checkpoint-id}. All program variables, registers, stack frames
2656etc.@: will be returned to the values that they had when the checkpoint
2657was saved. In essence, gdb will ``wind back the clock'' to the point
2658in time when the checkpoint was saved.
2659
2660Note that breakpoints, @value{GDBN} variables, command history etc.
2661are not affected by restoring a checkpoint. In general, a checkpoint
2662only restores things that reside in the program being debugged, not in
2663the debugger.
2664
2665@kindex delete-checkpoint @var{checkpoint-id}
2666@item delete-checkpoint @var{checkpoint-id}
2667Delete the previously-saved checkpoint identified by @var{checkpoint-id}.
2668
2669@end table
2670
2671Returning to a previously saved checkpoint will restore the user state
2672of the program being debugged, plus a significant subset of the system
2673(OS) state, including file pointers. It won't ``un-write'' data from
2674a file, but it will rewind the file pointer to the previous location,
2675so that the previously written data can be overwritten. For files
2676opened in read mode, the pointer will also be restored so that the
2677previously read data can be read again.
2678
2679Of course, characters that have been sent to a printer (or other
2680external device) cannot be ``snatched back'', and characters received
2681from eg.@: a serial device can be removed from internal program buffers,
2682but they cannot be ``pushed back'' into the serial pipeline, ready to
2683be received again. Similarly, the actual contents of files that have
2684been changed cannot be restored (at this time).
2685
2686However, within those constraints, you actually can ``rewind'' your
2687program to a previously saved point in time, and begin debugging it
2688again --- and you can change the course of events so as to debug a
2689different execution path this time.
2690
2691@cindex checkpoints and process id
2692Finally, there is one bit of internal program state that will be
2693different when you return to a checkpoint --- the program's process
2694id. Each checkpoint will have a unique process id (or @var{pid}),
2695and each will be different from the program's original @var{pid}.
2696If your program has saved a local copy of its process id, this could
2697potentially pose a problem.
2698
2699@subsection A non-obvious benefit of using checkpoints
2700
2701On some systems such as @sc{gnu}/Linux, address space randomization
2702is performed on new processes for security reasons. This makes it
2703difficult or impossible to set a breakpoint, or watchpoint, on an
2704absolute address if you have to restart the program, since the
2705absolute location of a symbol will change from one execution to the
2706next.
2707
2708A checkpoint, however, is an @emph{identical} copy of a process.
2709Therefore if you create a checkpoint at (eg.@:) the start of main,
2710and simply return to that checkpoint instead of restarting the
2711process, you can avoid the effects of address randomization and
2712your symbols will all stay in the same place.
2713
6d2ebf8b 2714@node Stopping
c906108c
SS
2715@chapter Stopping and Continuing
2716
2717The principal purposes of using a debugger are so that you can stop your
2718program before it terminates; or so that, if your program runs into
2719trouble, you can investigate and find out why.
2720
7a292a7a
SS
2721Inside @value{GDBN}, your program may stop for any of several reasons,
2722such as a signal, a breakpoint, or reaching a new line after a
2723@value{GDBN} command such as @code{step}. You may then examine and
2724change variables, set new breakpoints or remove old ones, and then
2725continue execution. Usually, the messages shown by @value{GDBN} provide
2726ample explanation of the status of your program---but you can also
2727explicitly request this information at any time.
c906108c
SS
2728
2729@table @code
2730@kindex info program
2731@item info program
2732Display information about the status of your program: whether it is
7a292a7a 2733running or not, what process it is, and why it stopped.
c906108c
SS
2734@end table
2735
2736@menu
2737* Breakpoints:: Breakpoints, watchpoints, and catchpoints
2738* Continuing and Stepping:: Resuming execution
c906108c 2739* Signals:: Signals
c906108c 2740* Thread Stops:: Stopping and starting multi-thread programs
c906108c
SS
2741@end menu
2742
6d2ebf8b 2743@node Breakpoints
c906108c
SS
2744@section Breakpoints, watchpoints, and catchpoints
2745
2746@cindex breakpoints
2747A @dfn{breakpoint} makes your program stop whenever a certain point in
2748the program is reached. For each breakpoint, you can add conditions to
2749control in finer detail whether your program stops. You can set
2750breakpoints with the @code{break} command and its variants (@pxref{Set
2751Breaks, ,Setting breakpoints}), to specify the place where your program
2752should stop by line number, function name or exact address in the
2753program.
2754
09d4efe1
EZ
2755On some systems, you can set breakpoints in shared libraries before
2756the executable is run. There is a minor limitation on HP-UX systems:
2757you must wait until the executable is run in order to set breakpoints
2758in shared library routines that are not called directly by the program
2759(for example, routines that are arguments in a @code{pthread_create}
2760call).
c906108c
SS
2761
2762@cindex watchpoints
2763@cindex memory tracing
2764@cindex breakpoint on memory address
2765@cindex breakpoint on variable modification
2766A @dfn{watchpoint} is a special breakpoint that stops your program
2767when the value of an expression changes. You must use a different
2768command to set watchpoints (@pxref{Set Watchpoints, ,Setting
2769watchpoints}), but aside from that, you can manage a watchpoint like
2770any other breakpoint: you enable, disable, and delete both breakpoints
2771and watchpoints using the same commands.
2772
2773You can arrange to have values from your program displayed automatically
2774whenever @value{GDBN} stops at a breakpoint. @xref{Auto Display,,
2775Automatic display}.
2776
2777@cindex catchpoints
2778@cindex breakpoint on events
2779A @dfn{catchpoint} is another special breakpoint that stops your program
b37052ae 2780when a certain kind of event occurs, such as the throwing of a C@t{++}
c906108c
SS
2781exception or the loading of a library. As with watchpoints, you use a
2782different command to set a catchpoint (@pxref{Set Catchpoints, ,Setting
2783catchpoints}), but aside from that, you can manage a catchpoint like any
2784other breakpoint. (To stop when your program receives a signal, use the
d4f3574e 2785@code{handle} command; see @ref{Signals, ,Signals}.)
c906108c
SS
2786
2787@cindex breakpoint numbers
2788@cindex numbers for breakpoints
2789@value{GDBN} assigns a number to each breakpoint, watchpoint, or
2790catchpoint when you create it; these numbers are successive integers
2791starting with one. In many of the commands for controlling various
2792features of breakpoints you use the breakpoint number to say which
2793breakpoint you want to change. Each breakpoint may be @dfn{enabled} or
2794@dfn{disabled}; if disabled, it has no effect on your program until you
2795enable it again.
2796
c5394b80
JM
2797@cindex breakpoint ranges
2798@cindex ranges of breakpoints
2799Some @value{GDBN} commands accept a range of breakpoints on which to
2800operate. A breakpoint range is either a single breakpoint number, like
2801@samp{5}, or two such numbers, in increasing order, separated by a
2802hyphen, like @samp{5-7}. When a breakpoint range is given to a command,
2803all breakpoint in that range are operated on.
2804
c906108c
SS
2805@menu
2806* Set Breaks:: Setting breakpoints
2807* Set Watchpoints:: Setting watchpoints
2808* Set Catchpoints:: Setting catchpoints
2809* Delete Breaks:: Deleting breakpoints
2810* Disabling:: Disabling breakpoints
2811* Conditions:: Break conditions
2812* Break Commands:: Breakpoint command lists
c906108c 2813* Breakpoint Menus:: Breakpoint menus
d4f3574e 2814* Error in Breakpoints:: ``Cannot insert breakpoints''
e4d5f7e1 2815* Breakpoint related warnings:: ``Breakpoint address adjusted...''
c906108c
SS
2816@end menu
2817
6d2ebf8b 2818@node Set Breaks
c906108c
SS
2819@subsection Setting breakpoints
2820
5d161b24 2821@c FIXME LMB what does GDB do if no code on line of breakpt?
c906108c
SS
2822@c consider in particular declaration with/without initialization.
2823@c
2824@c FIXME 2 is there stuff on this already? break at fun start, already init?
2825
2826@kindex break
41afff9a
EZ
2827@kindex b @r{(@code{break})}
2828@vindex $bpnum@r{, convenience variable}
c906108c
SS
2829@cindex latest breakpoint
2830Breakpoints are set with the @code{break} command (abbreviated
5d161b24 2831@code{b}). The debugger convenience variable @samp{$bpnum} records the
f3b28801 2832number of the breakpoint you've set most recently; see @ref{Convenience
c906108c
SS
2833Vars,, Convenience variables}, for a discussion of what you can do with
2834convenience variables.
2835
2836You have several ways to say where the breakpoint should go.
2837
2838@table @code
2839@item break @var{function}
5d161b24 2840Set a breakpoint at entry to function @var{function}.
c906108c 2841When using source languages that permit overloading of symbols, such as
b37052ae 2842C@t{++}, @var{function} may refer to more than one possible place to break.
c906108c 2843@xref{Breakpoint Menus,,Breakpoint menus}, for a discussion of that situation.
c906108c
SS
2844
2845@item break +@var{offset}
2846@itemx break -@var{offset}
2847Set a breakpoint some number of lines forward or back from the position
d4f3574e 2848at which execution stopped in the currently selected @dfn{stack frame}.
2df3850c 2849(@xref{Frames, ,Frames}, for a description of stack frames.)
c906108c
SS
2850
2851@item break @var{linenum}
2852Set a breakpoint at line @var{linenum} in the current source file.
d4f3574e
SS
2853The current source file is the last file whose source text was printed.
2854The breakpoint will stop your program just before it executes any of the
c906108c
SS
2855code on that line.
2856
2857@item break @var{filename}:@var{linenum}
2858Set a breakpoint at line @var{linenum} in source file @var{filename}.
2859
2860@item break @var{filename}:@var{function}
2861Set a breakpoint at entry to function @var{function} found in file
2862@var{filename}. Specifying a file name as well as a function name is
2863superfluous except when multiple files contain similarly named
2864functions.
2865
2866@item break *@var{address}
2867Set a breakpoint at address @var{address}. You can use this to set
2868breakpoints in parts of your program which do not have debugging
2869information or source files.
2870
2871@item break
2872When called without any arguments, @code{break} sets a breakpoint at
2873the next instruction to be executed in the selected stack frame
2874(@pxref{Stack, ,Examining the Stack}). In any selected frame but the
2875innermost, this makes your program stop as soon as control
2876returns to that frame. This is similar to the effect of a
2877@code{finish} command in the frame inside the selected frame---except
2878that @code{finish} does not leave an active breakpoint. If you use
2879@code{break} without an argument in the innermost frame, @value{GDBN} stops
2880the next time it reaches the current location; this may be useful
2881inside loops.
2882
2883@value{GDBN} normally ignores breakpoints when it resumes execution, until at
2884least one instruction has been executed. If it did not do this, you
2885would be unable to proceed past a breakpoint without first disabling the
2886breakpoint. This rule applies whether or not the breakpoint already
2887existed when your program stopped.
2888
2889@item break @dots{} if @var{cond}
2890Set a breakpoint with condition @var{cond}; evaluate the expression
2891@var{cond} each time the breakpoint is reached, and stop only if the
2892value is nonzero---that is, if @var{cond} evaluates as true.
2893@samp{@dots{}} stands for one of the possible arguments described
2894above (or no argument) specifying where to break. @xref{Conditions,
2895,Break conditions}, for more information on breakpoint conditions.
2896
2897@kindex tbreak
2898@item tbreak @var{args}
2899Set a breakpoint enabled only for one stop. @var{args} are the
2900same as for the @code{break} command, and the breakpoint is set in the same
2901way, but the breakpoint is automatically deleted after the first time your
2902program stops there. @xref{Disabling, ,Disabling breakpoints}.
2903
c906108c 2904@kindex hbreak
ba04e063 2905@cindex hardware breakpoints
c906108c 2906@item hbreak @var{args}
d4f3574e
SS
2907Set a hardware-assisted breakpoint. @var{args} are the same as for the
2908@code{break} command and the breakpoint is set in the same way, but the
c906108c
SS
2909breakpoint requires hardware support and some target hardware may not
2910have this support. The main purpose of this is EPROM/ROM code
d4f3574e
SS
2911debugging, so you can set a breakpoint at an instruction without
2912changing the instruction. This can be used with the new trap-generation
09d4efe1 2913provided by SPARClite DSU and most x86-based targets. These targets
d4f3574e
SS
2914will generate traps when a program accesses some data or instruction
2915address that is assigned to the debug registers. However the hardware
2916breakpoint registers can take a limited number of breakpoints. For
2917example, on the DSU, only two data breakpoints can be set at a time, and
2918@value{GDBN} will reject this command if more than two are used. Delete
2919or disable unused hardware breakpoints before setting new ones
2920(@pxref{Disabling, ,Disabling}). @xref{Conditions, ,Break conditions}.
9c16f35a
EZ
2921For remote targets, you can restrict the number of hardware
2922breakpoints @value{GDBN} will use, see @ref{set remote
2923hardware-breakpoint-limit}.
501eef12 2924
c906108c
SS
2925
2926@kindex thbreak
2927@item thbreak @var{args}
2928Set a hardware-assisted breakpoint enabled only for one stop. @var{args}
2929are the same as for the @code{hbreak} command and the breakpoint is set in
5d161b24 2930the same way. However, like the @code{tbreak} command,
c906108c
SS
2931the breakpoint is automatically deleted after the
2932first time your program stops there. Also, like the @code{hbreak}
5d161b24
DB
2933command, the breakpoint requires hardware support and some target hardware
2934may not have this support. @xref{Disabling, ,Disabling breakpoints}.
d4f3574e 2935See also @ref{Conditions, ,Break conditions}.
c906108c
SS
2936
2937@kindex rbreak
2938@cindex regular expression
c45da7e6
EZ
2939@cindex breakpoints in functions matching a regexp
2940@cindex set breakpoints in many functions
c906108c 2941@item rbreak @var{regex}
c906108c 2942Set breakpoints on all functions matching the regular expression
11cf8741
JM
2943@var{regex}. This command sets an unconditional breakpoint on all
2944matches, printing a list of all breakpoints it set. Once these
2945breakpoints are set, they are treated just like the breakpoints set with
2946the @code{break} command. You can delete them, disable them, or make
2947them conditional the same way as any other breakpoint.
2948
2949The syntax of the regular expression is the standard one used with tools
2950like @file{grep}. Note that this is different from the syntax used by
2951shells, so for instance @code{foo*} matches all functions that include
2952an @code{fo} followed by zero or more @code{o}s. There is an implicit
2953@code{.*} leading and trailing the regular expression you supply, so to
2954match only functions that begin with @code{foo}, use @code{^foo}.
c906108c 2955
f7dc1244 2956@cindex non-member C@t{++} functions, set breakpoint in
b37052ae 2957When debugging C@t{++} programs, @code{rbreak} is useful for setting
c906108c
SS
2958breakpoints on overloaded functions that are not members of any special
2959classes.
c906108c 2960
f7dc1244
EZ
2961@cindex set breakpoints on all functions
2962The @code{rbreak} command can be used to set breakpoints in
2963@strong{all} the functions in a program, like this:
2964
2965@smallexample
2966(@value{GDBP}) rbreak .
2967@end smallexample
2968
c906108c
SS
2969@kindex info breakpoints
2970@cindex @code{$_} and @code{info breakpoints}
2971@item info breakpoints @r{[}@var{n}@r{]}
2972@itemx info break @r{[}@var{n}@r{]}
2973@itemx info watchpoints @r{[}@var{n}@r{]}
2974Print a table of all breakpoints, watchpoints, and catchpoints set and
2975not deleted, with the following columns for each breakpoint:
2976
2977@table @emph
2978@item Breakpoint Numbers
2979@item Type
2980Breakpoint, watchpoint, or catchpoint.
2981@item Disposition
2982Whether the breakpoint is marked to be disabled or deleted when hit.
2983@item Enabled or Disabled
2984Enabled breakpoints are marked with @samp{y}. @samp{n} marks breakpoints
2985that are not enabled.
2986@item Address
2650777c
JJ
2987Where the breakpoint is in your program, as a memory address. If the
2988breakpoint is pending (see below for details) on a future load of a shared library, the address
2989will be listed as @samp{<PENDING>}.
c906108c
SS
2990@item What
2991Where the breakpoint is in the source for your program, as a file and
2650777c
JJ
2992line number. For a pending breakpoint, the original string passed to
2993the breakpoint command will be listed as it cannot be resolved until
2994the appropriate shared library is loaded in the future.
c906108c
SS
2995@end table
2996
2997@noindent
2998If a breakpoint is conditional, @code{info break} shows the condition on
2999the line following the affected breakpoint; breakpoint commands, if any,
2650777c
JJ
3000are listed after that. A pending breakpoint is allowed to have a condition
3001specified for it. The condition is not parsed for validity until a shared
3002library is loaded that allows the pending breakpoint to resolve to a
3003valid location.
c906108c
SS
3004
3005@noindent
3006@code{info break} with a breakpoint
3007number @var{n} as argument lists only that breakpoint. The
3008convenience variable @code{$_} and the default examining-address for
3009the @code{x} command are set to the address of the last breakpoint
5d161b24 3010listed (@pxref{Memory, ,Examining memory}).
c906108c
SS
3011
3012@noindent
3013@code{info break} displays a count of the number of times the breakpoint
3014has been hit. This is especially useful in conjunction with the
3015@code{ignore} command. You can ignore a large number of breakpoint
3016hits, look at the breakpoint info to see how many times the breakpoint
3017was hit, and then run again, ignoring one less than that number. This
3018will get you quickly to the last hit of that breakpoint.
3019@end table
3020
3021@value{GDBN} allows you to set any number of breakpoints at the same place in
3022your program. There is nothing silly or meaningless about this. When
3023the breakpoints are conditional, this is even useful
3024(@pxref{Conditions, ,Break conditions}).
3025
2650777c 3026@cindex pending breakpoints
dd79a6cf
JJ
3027If a specified breakpoint location cannot be found, it may be due to the fact
3028that the location is in a shared library that is yet to be loaded. In such
3029a case, you may want @value{GDBN} to create a special breakpoint (known as
3030a @dfn{pending breakpoint}) that
3031attempts to resolve itself in the future when an appropriate shared library
3032gets loaded.
3033
3034Pending breakpoints are useful to set at the start of your
2650777c
JJ
3035@value{GDBN} session for locations that you know will be dynamically loaded
3036later by the program being debugged. When shared libraries are loaded,
dd79a6cf
JJ
3037a check is made to see if the load resolves any pending breakpoint locations.
3038If a pending breakpoint location gets resolved,
3039a regular breakpoint is created and the original pending breakpoint is removed.
3040
3041@value{GDBN} provides some additional commands for controlling pending
3042breakpoint support:
3043
3044@kindex set breakpoint pending
3045@kindex show breakpoint pending
3046@table @code
3047@item set breakpoint pending auto
3048This is the default behavior. When @value{GDBN} cannot find the breakpoint
3049location, it queries you whether a pending breakpoint should be created.
3050
3051@item set breakpoint pending on
3052This indicates that an unrecognized breakpoint location should automatically
3053result in a pending breakpoint being created.
3054
3055@item set breakpoint pending off
3056This indicates that pending breakpoints are not to be created. Any
3057unrecognized breakpoint location results in an error. This setting does
3058not affect any pending breakpoints previously created.
3059
3060@item show breakpoint pending
3061Show the current behavior setting for creating pending breakpoints.
3062@end table
2650777c 3063
649e03f6
RM
3064@cindex operations allowed on pending breakpoints
3065Normal breakpoint operations apply to pending breakpoints as well. You may
3066specify a condition for a pending breakpoint and/or commands to run when the
2650777c
JJ
3067breakpoint is reached. You can also enable or disable
3068the pending breakpoint. When you specify a condition for a pending breakpoint,
3069the parsing of the condition will be deferred until the point where the
3070pending breakpoint location is resolved. Disabling a pending breakpoint
3071tells @value{GDBN} to not attempt to resolve the breakpoint on any subsequent
3072shared library load. When a pending breakpoint is re-enabled,
649e03f6 3073@value{GDBN} checks to see if the location is already resolved.
2650777c
JJ
3074This is done because any number of shared library loads could have
3075occurred since the time the breakpoint was disabled and one or more
3076of these loads could resolve the location.
3077
c906108c
SS
3078@cindex negative breakpoint numbers
3079@cindex internal @value{GDBN} breakpoints
eb12ee30
AC
3080@value{GDBN} itself sometimes sets breakpoints in your program for
3081special purposes, such as proper handling of @code{longjmp} (in C
3082programs). These internal breakpoints are assigned negative numbers,
3083starting with @code{-1}; @samp{info breakpoints} does not display them.
c906108c 3084You can see these breakpoints with the @value{GDBN} maintenance command
eb12ee30 3085@samp{maint info breakpoints} (@pxref{maint info breakpoints}).
c906108c
SS
3086
3087
6d2ebf8b 3088@node Set Watchpoints
c906108c
SS
3089@subsection Setting watchpoints
3090
3091@cindex setting watchpoints
c906108c
SS
3092You can use a watchpoint to stop execution whenever the value of an
3093expression changes, without having to predict a particular place where
3094this may happen.
3095
82f2d802
EZ
3096@cindex software watchpoints
3097@cindex hardware watchpoints
c906108c 3098Depending on your system, watchpoints may be implemented in software or
2df3850c 3099hardware. @value{GDBN} does software watchpointing by single-stepping your
c906108c
SS
3100program and testing the variable's value each time, which is hundreds of
3101times slower than normal execution. (But this may still be worth it, to
3102catch errors where you have no clue what part of your program is the
3103culprit.)
3104
82f2d802
EZ
3105On some systems, such as HP-UX, @sc{gnu}/Linux and most other
3106x86-based targets, @value{GDBN} includes support for hardware
3107watchpoints, which do not slow down the running of your program.
c906108c
SS
3108
3109@table @code
3110@kindex watch
3111@item watch @var{expr}
3112Set a watchpoint for an expression. @value{GDBN} will break when @var{expr}
3113is written into by the program and its value changes.
3114
3115@kindex rwatch
3116@item rwatch @var{expr}
09d4efe1
EZ
3117Set a watchpoint that will break when the value of @var{expr} is read
3118by the program.
c906108c
SS
3119
3120@kindex awatch
3121@item awatch @var{expr}
09d4efe1
EZ
3122Set a watchpoint that will break when @var{expr} is either read from
3123or written into by the program.
c906108c
SS
3124
3125@kindex info watchpoints
3126@item info watchpoints
3127This command prints a list of watchpoints, breakpoints, and catchpoints;
09d4efe1 3128it is the same as @code{info break} (@pxref{Set Breaks}).
c906108c
SS
3129@end table
3130
3131@value{GDBN} sets a @dfn{hardware watchpoint} if possible. Hardware
3132watchpoints execute very quickly, and the debugger reports a change in
3133value at the exact instruction where the change occurs. If @value{GDBN}
3134cannot set a hardware watchpoint, it sets a software watchpoint, which
3135executes more slowly and reports the change in value at the next
82f2d802
EZ
3136@emph{statement}, not the instruction, after the change occurs.
3137
82f2d802
EZ
3138@cindex use only software watchpoints
3139You can force @value{GDBN} to use only software watchpoints with the
3140@kbd{set can-use-hw-watchpoints 0} command. With this variable set to
3141zero, @value{GDBN} will never try to use hardware watchpoints, even if
3142the underlying system supports them. (Note that hardware-assisted
3143watchpoints that were set @emph{before} setting
3144@code{can-use-hw-watchpoints} to zero will still use the hardware
3145mechanism of watching expressiion values.)
c906108c 3146
9c16f35a
EZ
3147@table @code
3148@item set can-use-hw-watchpoints
3149@kindex set can-use-hw-watchpoints
3150Set whether or not to use hardware watchpoints.
3151
3152@item show can-use-hw-watchpoints
3153@kindex show can-use-hw-watchpoints
3154Show the current mode of using hardware watchpoints.
3155@end table
3156
3157For remote targets, you can restrict the number of hardware
3158watchpoints @value{GDBN} will use, see @ref{set remote
3159hardware-breakpoint-limit}.
3160
c906108c
SS
3161When you issue the @code{watch} command, @value{GDBN} reports
3162
474c8240 3163@smallexample
c906108c 3164Hardware watchpoint @var{num}: @var{expr}
474c8240 3165@end smallexample
c906108c
SS
3166
3167@noindent
3168if it was able to set a hardware watchpoint.
3169
7be570e7
JM
3170Currently, the @code{awatch} and @code{rwatch} commands can only set
3171hardware watchpoints, because accesses to data that don't change the
3172value of the watched expression cannot be detected without examining
3173every instruction as it is being executed, and @value{GDBN} does not do
3174that currently. If @value{GDBN} finds that it is unable to set a
3175hardware breakpoint with the @code{awatch} or @code{rwatch} command, it
3176will print a message like this:
3177
3178@smallexample
3179Expression cannot be implemented with read/access watchpoint.
3180@end smallexample
3181
3182Sometimes, @value{GDBN} cannot set a hardware watchpoint because the
3183data type of the watched expression is wider than what a hardware
3184watchpoint on the target machine can handle. For example, some systems
3185can only watch regions that are up to 4 bytes wide; on such systems you
3186cannot set hardware watchpoints for an expression that yields a
3187double-precision floating-point number (which is typically 8 bytes
3188wide). As a work-around, it might be possible to break the large region
3189into a series of smaller ones and watch them with separate watchpoints.
3190
3191If you set too many hardware watchpoints, @value{GDBN} might be unable
3192to insert all of them when you resume the execution of your program.
3193Since the precise number of active watchpoints is unknown until such
3194time as the program is about to be resumed, @value{GDBN} might not be
3195able to warn you about this when you set the watchpoints, and the
3196warning will be printed only when the program is resumed:
3197
3198@smallexample
3199Hardware watchpoint @var{num}: Could not insert watchpoint
3200@end smallexample
3201
3202@noindent
3203If this happens, delete or disable some of the watchpoints.
3204
3205The SPARClite DSU will generate traps when a program accesses some data
3206or instruction address that is assigned to the debug registers. For the
3207data addresses, DSU facilitates the @code{watch} command. However the
3208hardware breakpoint registers can only take two data watchpoints, and
3209both watchpoints must be the same kind. For example, you can set two
3210watchpoints with @code{watch} commands, two with @code{rwatch} commands,
3211@strong{or} two with @code{awatch} commands, but you cannot set one
3212watchpoint with one command and the other with a different command.
c906108c
SS
3213@value{GDBN} will reject the command if you try to mix watchpoints.
3214Delete or disable unused watchpoint commands before setting new ones.
3215
3216If you call a function interactively using @code{print} or @code{call},
2df3850c 3217any watchpoints you have set will be inactive until @value{GDBN} reaches another
c906108c
SS
3218kind of breakpoint or the call completes.
3219
7be570e7
JM
3220@value{GDBN} automatically deletes watchpoints that watch local
3221(automatic) variables, or expressions that involve such variables, when
3222they go out of scope, that is, when the execution leaves the block in
3223which these variables were defined. In particular, when the program
3224being debugged terminates, @emph{all} local variables go out of scope,
3225and so only watchpoints that watch global variables remain set. If you
3226rerun the program, you will need to set all such watchpoints again. One
3227way of doing that would be to set a code breakpoint at the entry to the
3228@code{main} function and when it breaks, set all the watchpoints.
3229
c906108c
SS
3230@quotation
3231@cindex watchpoints and threads
3232@cindex threads and watchpoints
c906108c
SS
3233@emph{Warning:} In multi-thread programs, watchpoints have only limited
3234usefulness. With the current watchpoint implementation, @value{GDBN}
3235can only watch the value of an expression @emph{in a single thread}. If
3236you are confident that the expression can only change due to the current
3237thread's activity (and if you are also confident that no other thread
3238can become current), then you can use watchpoints as usual. However,
3239@value{GDBN} may not notice when a non-current thread's activity changes
3240the expression.
53a5351d 3241
d4f3574e 3242@c FIXME: this is almost identical to the previous paragraph.
53a5351d
JM
3243@emph{HP-UX Warning:} In multi-thread programs, software watchpoints
3244have only limited usefulness. If @value{GDBN} creates a software
3245watchpoint, it can only watch the value of an expression @emph{in a
3246single thread}. If you are confident that the expression can only
3247change due to the current thread's activity (and if you are also
3248confident that no other thread can become current), then you can use
3249software watchpoints as usual. However, @value{GDBN} may not notice
3250when a non-current thread's activity changes the expression. (Hardware
3251watchpoints, in contrast, watch an expression in all threads.)
c906108c 3252@end quotation
c906108c 3253
501eef12
AC
3254@xref{set remote hardware-watchpoint-limit}.
3255
6d2ebf8b 3256@node Set Catchpoints
c906108c 3257@subsection Setting catchpoints
d4f3574e 3258@cindex catchpoints, setting
c906108c
SS
3259@cindex exception handlers
3260@cindex event handling
3261
3262You can use @dfn{catchpoints} to cause the debugger to stop for certain
b37052ae 3263kinds of program events, such as C@t{++} exceptions or the loading of a
c906108c
SS
3264shared library. Use the @code{catch} command to set a catchpoint.
3265
3266@table @code
3267@kindex catch
3268@item catch @var{event}
3269Stop when @var{event} occurs. @var{event} can be any of the following:
3270@table @code
3271@item throw
4644b6e3 3272@cindex stop on C@t{++} exceptions
b37052ae 3273The throwing of a C@t{++} exception.
c906108c
SS
3274
3275@item catch
b37052ae 3276The catching of a C@t{++} exception.
c906108c
SS
3277
3278@item exec
4644b6e3 3279@cindex break on fork/exec
c906108c
SS
3280A call to @code{exec}. This is currently only available for HP-UX.
3281
3282@item fork
c906108c
SS
3283A call to @code{fork}. This is currently only available for HP-UX.
3284
3285@item vfork
c906108c
SS
3286A call to @code{vfork}. This is currently only available for HP-UX.
3287
3288@item load
3289@itemx load @var{libname}
4644b6e3 3290@cindex break on load/unload of shared library
c906108c
SS
3291The dynamic loading of any shared library, or the loading of the library
3292@var{libname}. This is currently only available for HP-UX.
3293
3294@item unload
3295@itemx unload @var{libname}
c906108c
SS
3296The unloading of any dynamically loaded shared library, or the unloading
3297of the library @var{libname}. This is currently only available for HP-UX.
3298@end table
3299
3300@item tcatch @var{event}
3301Set a catchpoint that is enabled only for one stop. The catchpoint is
3302automatically deleted after the first time the event is caught.
3303
3304@end table
3305
3306Use the @code{info break} command to list the current catchpoints.
3307
b37052ae 3308There are currently some limitations to C@t{++} exception handling
c906108c
SS
3309(@code{catch throw} and @code{catch catch}) in @value{GDBN}:
3310
3311@itemize @bullet
3312@item
3313If you call a function interactively, @value{GDBN} normally returns
3314control to you when the function has finished executing. If the call
3315raises an exception, however, the call may bypass the mechanism that
3316returns control to you and cause your program either to abort or to
3317simply continue running until it hits a breakpoint, catches a signal
3318that @value{GDBN} is listening for, or exits. This is the case even if
3319you set a catchpoint for the exception; catchpoints on exceptions are
3320disabled within interactive calls.
3321
3322@item
3323You cannot raise an exception interactively.
3324
3325@item
3326You cannot install an exception handler interactively.
3327@end itemize
3328
3329@cindex raise exceptions
3330Sometimes @code{catch} is not the best way to debug exception handling:
3331if you need to know exactly where an exception is raised, it is better to
3332stop @emph{before} the exception handler is called, since that way you
3333can see the stack before any unwinding takes place. If you set a
3334breakpoint in an exception handler instead, it may not be easy to find
3335out where the exception was raised.
3336
3337To stop just before an exception handler is called, you need some
b37052ae 3338knowledge of the implementation. In the case of @sc{gnu} C@t{++}, exceptions are
c906108c
SS
3339raised by calling a library function named @code{__raise_exception}
3340which has the following ANSI C interface:
3341
474c8240 3342@smallexample
c906108c 3343 /* @var{addr} is where the exception identifier is stored.
d4f3574e
SS
3344 @var{id} is the exception identifier. */
3345 void __raise_exception (void **addr, void *id);
474c8240 3346@end smallexample
c906108c
SS
3347
3348@noindent
3349To make the debugger catch all exceptions before any stack
3350unwinding takes place, set a breakpoint on @code{__raise_exception}
3351(@pxref{Breakpoints, ,Breakpoints; watchpoints; and exceptions}).
3352
3353With a conditional breakpoint (@pxref{Conditions, ,Break conditions})
3354that depends on the value of @var{id}, you can stop your program when
3355a specific exception is raised. You can use multiple conditional
3356breakpoints to stop your program when any of a number of exceptions are
3357raised.
3358
3359
6d2ebf8b 3360@node Delete Breaks
c906108c
SS
3361@subsection Deleting breakpoints
3362
3363@cindex clearing breakpoints, watchpoints, catchpoints
3364@cindex deleting breakpoints, watchpoints, catchpoints
3365It is often necessary to eliminate a breakpoint, watchpoint, or
3366catchpoint once it has done its job and you no longer want your program
3367to stop there. This is called @dfn{deleting} the breakpoint. A
3368breakpoint that has been deleted no longer exists; it is forgotten.
3369
3370With the @code{clear} command you can delete breakpoints according to
3371where they are in your program. With the @code{delete} command you can
3372delete individual breakpoints, watchpoints, or catchpoints by specifying
3373their breakpoint numbers.
3374
3375It is not necessary to delete a breakpoint to proceed past it. @value{GDBN}
3376automatically ignores breakpoints on the first instruction to be executed
3377when you continue execution without changing the execution address.
3378
3379@table @code
3380@kindex clear
3381@item clear
3382Delete any breakpoints at the next instruction to be executed in the
3383selected stack frame (@pxref{Selection, ,Selecting a frame}). When
3384the innermost frame is selected, this is a good way to delete a
3385breakpoint where your program just stopped.
3386
3387@item clear @var{function}
3388@itemx clear @var{filename}:@var{function}
09d4efe1 3389Delete any breakpoints set at entry to the named @var{function}.
c906108c
SS
3390
3391@item clear @var{linenum}
3392@itemx clear @var{filename}:@var{linenum}
09d4efe1
EZ
3393Delete any breakpoints set at or within the code of the specified
3394@var{linenum} of the specified @var{filename}.
c906108c
SS
3395
3396@cindex delete breakpoints
3397@kindex delete
41afff9a 3398@kindex d @r{(@code{delete})}
c5394b80
JM
3399@item delete @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]}
3400Delete the breakpoints, watchpoints, or catchpoints of the breakpoint
3401ranges specified as arguments. If no argument is specified, delete all
c906108c
SS
3402breakpoints (@value{GDBN} asks confirmation, unless you have @code{set
3403confirm off}). You can abbreviate this command as @code{d}.
3404@end table
3405
6d2ebf8b 3406@node Disabling
c906108c
SS
3407@subsection Disabling breakpoints
3408
4644b6e3 3409@cindex enable/disable a breakpoint
c906108c
SS
3410Rather than deleting a breakpoint, watchpoint, or catchpoint, you might
3411prefer to @dfn{disable} it. This makes the breakpoint inoperative as if
3412it had been deleted, but remembers the information on the breakpoint so
3413that you can @dfn{enable} it again later.
3414
3415You disable and enable breakpoints, watchpoints, and catchpoints with
3416the @code{enable} and @code{disable} commands, optionally specifying one
3417or more breakpoint numbers as arguments. Use @code{info break} or
3418@code{info watch} to print a list of breakpoints, watchpoints, and
3419catchpoints if you do not know which numbers to use.
3420
3421A breakpoint, watchpoint, or catchpoint can have any of four different
3422states of enablement:
3423
3424@itemize @bullet
3425@item
3426Enabled. The breakpoint stops your program. A breakpoint set
3427with the @code{break} command starts out in this state.
3428@item
3429Disabled. The breakpoint has no effect on your program.
3430@item
3431Enabled once. The breakpoint stops your program, but then becomes
d4f3574e 3432disabled.
c906108c
SS
3433@item
3434Enabled for deletion. The breakpoint stops your program, but
d4f3574e
SS
3435immediately after it does so it is deleted permanently. A breakpoint
3436set with the @code{tbreak} command starts out in this state.
c906108c
SS
3437@end itemize
3438
3439You can use the following commands to enable or disable breakpoints,
3440watchpoints, and catchpoints:
3441
3442@table @code
c906108c 3443@kindex disable
41afff9a 3444@kindex dis @r{(@code{disable})}
c5394b80 3445@item disable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]}
c906108c
SS
3446Disable the specified breakpoints---or all breakpoints, if none are
3447listed. A disabled breakpoint has no effect but is not forgotten. All
3448options such as ignore-counts, conditions and commands are remembered in
3449case the breakpoint is enabled again later. You may abbreviate
3450@code{disable} as @code{dis}.
3451
c906108c 3452@kindex enable
c5394b80 3453@item enable @r{[}breakpoints@r{]} @r{[}@var{range}@dots{}@r{]}
c906108c
SS
3454Enable the specified breakpoints (or all defined breakpoints). They
3455become effective once again in stopping your program.
3456
c5394b80 3457@item enable @r{[}breakpoints@r{]} once @var{range}@dots{}
c906108c
SS
3458Enable the specified breakpoints temporarily. @value{GDBN} disables any
3459of these breakpoints immediately after stopping your program.
3460
c5394b80 3461@item enable @r{[}breakpoints@r{]} delete @var{range}@dots{}
c906108c
SS
3462Enable the specified breakpoints to work once, then die. @value{GDBN}
3463deletes any of these breakpoints as soon as your program stops there.
09d4efe1 3464Breakpoints set by the @code{tbreak} command start out in this state.
c906108c
SS
3465@end table
3466
d4f3574e
SS
3467@c FIXME: I think the following ``Except for [...] @code{tbreak}'' is
3468@c confusing: tbreak is also initially enabled.
c906108c
SS
3469Except for a breakpoint set with @code{tbreak} (@pxref{Set Breaks,
3470,Setting breakpoints}), breakpoints that you set are initially enabled;
3471subsequently, they become disabled or enabled only when you use one of
3472the commands above. (The command @code{until} can set and delete a
3473breakpoint of its own, but it does not change the state of your other
3474breakpoints; see @ref{Continuing and Stepping, ,Continuing and
3475stepping}.)
3476
6d2ebf8b 3477@node Conditions
c906108c
SS
3478@subsection Break conditions
3479@cindex conditional breakpoints
3480@cindex breakpoint conditions
3481
3482@c FIXME what is scope of break condition expr? Context where wanted?
5d161b24 3483@c in particular for a watchpoint?
c906108c
SS
3484The simplest sort of breakpoint breaks every time your program reaches a
3485specified place. You can also specify a @dfn{condition} for a
3486breakpoint. A condition is just a Boolean expression in your
3487programming language (@pxref{Expressions, ,Expressions}). A breakpoint with
3488a condition evaluates the expression each time your program reaches it,
3489and your program stops only if the condition is @emph{true}.
3490
3491This is the converse of using assertions for program validation; in that
3492situation, you want to stop when the assertion is violated---that is,
3493when the condition is false. In C, if you want to test an assertion expressed
3494by the condition @var{assert}, you should set the condition
3495@samp{! @var{assert}} on the appropriate breakpoint.
3496
3497Conditions are also accepted for watchpoints; you may not need them,
3498since a watchpoint is inspecting the value of an expression anyhow---but
3499it might be simpler, say, to just set a watchpoint on a variable name,
3500and specify a condition that tests whether the new value is an interesting
3501one.
3502
3503Break conditions can have side effects, and may even call functions in
3504your program. This can be useful, for example, to activate functions
3505that log program progress, or to use your own print functions to
3506format special data structures. The effects are completely predictable
3507unless there is another enabled breakpoint at the same address. (In
3508that case, @value{GDBN} might see the other breakpoint first and stop your
3509program without checking the condition of this one.) Note that
d4f3574e
SS
3510breakpoint commands are usually more convenient and flexible than break
3511conditions for the
c906108c
SS
3512purpose of performing side effects when a breakpoint is reached
3513(@pxref{Break Commands, ,Breakpoint command lists}).
3514
3515Break conditions can be specified when a breakpoint is set, by using
3516@samp{if} in the arguments to the @code{break} command. @xref{Set
3517Breaks, ,Setting breakpoints}. They can also be changed at any time
3518with the @code{condition} command.
53a5351d 3519
c906108c
SS
3520You can also use the @code{if} keyword with the @code{watch} command.
3521The @code{catch} command does not recognize the @code{if} keyword;
3522@code{condition} is the only way to impose a further condition on a
3523catchpoint.
c906108c
SS
3524
3525@table @code
3526@kindex condition
3527@item condition @var{bnum} @var{expression}
3528Specify @var{expression} as the break condition for breakpoint,
3529watchpoint, or catchpoint number @var{bnum}. After you set a condition,
3530breakpoint @var{bnum} stops your program only if the value of
3531@var{expression} is true (nonzero, in C). When you use
3532@code{condition}, @value{GDBN} checks @var{expression} immediately for
3533syntactic correctness, and to determine whether symbols in it have
d4f3574e
SS
3534referents in the context of your breakpoint. If @var{expression} uses
3535symbols not referenced in the context of the breakpoint, @value{GDBN}
3536prints an error message:
3537
474c8240 3538@smallexample
d4f3574e 3539No symbol "foo" in current context.
474c8240 3540@end smallexample
d4f3574e
SS
3541
3542@noindent
c906108c
SS
3543@value{GDBN} does
3544not actually evaluate @var{expression} at the time the @code{condition}
d4f3574e
SS
3545command (or a command that sets a breakpoint with a condition, like
3546@code{break if @dots{}}) is given, however. @xref{Expressions, ,Expressions}.
c906108c
SS
3547
3548@item condition @var{bnum}
3549Remove the condition from breakpoint number @var{bnum}. It becomes
3550an ordinary unconditional breakpoint.
3551@end table
3552
3553@cindex ignore count (of breakpoint)
3554A special case of a breakpoint condition is to stop only when the
3555breakpoint has been reached a certain number of times. This is so
3556useful that there is a special way to do it, using the @dfn{ignore
3557count} of the breakpoint. Every breakpoint has an ignore count, which
3558is an integer. Most of the time, the ignore count is zero, and
3559therefore has no effect. But if your program reaches a breakpoint whose
3560ignore count is positive, then instead of stopping, it just decrements
3561the ignore count by one and continues. As a result, if the ignore count
3562value is @var{n}, the breakpoint does not stop the next @var{n} times
3563your program reaches it.
3564
3565@table @code
3566@kindex ignore
3567@item ignore @var{bnum} @var{count}
3568Set the ignore count of breakpoint number @var{bnum} to @var{count}.
3569The next @var{count} times the breakpoint is reached, your program's
3570execution does not stop; other than to decrement the ignore count, @value{GDBN}
3571takes no action.
3572
3573To make the breakpoint stop the next time it is reached, specify
3574a count of zero.
3575
3576When you use @code{continue} to resume execution of your program from a
3577breakpoint, you can specify an ignore count directly as an argument to
3578@code{continue}, rather than using @code{ignore}. @xref{Continuing and
3579Stepping,,Continuing and stepping}.
3580
3581If a breakpoint has a positive ignore count and a condition, the
3582condition is not checked. Once the ignore count reaches zero,
3583@value{GDBN} resumes checking the condition.
3584
3585You could achieve the effect of the ignore count with a condition such
3586as @w{@samp{$foo-- <= 0}} using a debugger convenience variable that
3587is decremented each time. @xref{Convenience Vars, ,Convenience
3588variables}.
3589@end table
3590
3591Ignore counts apply to breakpoints, watchpoints, and catchpoints.
3592
3593
6d2ebf8b 3594@node Break Commands
c906108c
SS
3595@subsection Breakpoint command lists
3596
3597@cindex breakpoint commands
3598You can give any breakpoint (or watchpoint or catchpoint) a series of
3599commands to execute when your program stops due to that breakpoint. For
3600example, you might want to print the values of certain expressions, or
3601enable other breakpoints.
3602
3603@table @code
3604@kindex commands
ca91424e 3605@kindex end@r{ (breakpoint commands)}
c906108c
SS
3606@item commands @r{[}@var{bnum}@r{]}
3607@itemx @dots{} @var{command-list} @dots{}
3608@itemx end
3609Specify a list of commands for breakpoint number @var{bnum}. The commands
3610themselves appear on the following lines. Type a line containing just
3611@code{end} to terminate the commands.
3612
3613To remove all commands from a breakpoint, type @code{commands} and
3614follow it immediately with @code{end}; that is, give no commands.
3615
3616With no @var{bnum} argument, @code{commands} refers to the last
3617breakpoint, watchpoint, or catchpoint set (not to the breakpoint most
3618recently encountered).
3619@end table
3620
3621Pressing @key{RET} as a means of repeating the last @value{GDBN} command is
3622disabled within a @var{command-list}.
3623
3624You can use breakpoint commands to start your program up again. Simply
3625use the @code{continue} command, or @code{step}, or any other command
3626that resumes execution.
3627
3628Any other commands in the command list, after a command that resumes
3629execution, are ignored. This is because any time you resume execution
3630(even with a simple @code{next} or @code{step}), you may encounter
3631another breakpoint---which could have its own command list, leading to
3632ambiguities about which list to execute.
3633
3634@kindex silent
3635If the first command you specify in a command list is @code{silent}, the
3636usual message about stopping at a breakpoint is not printed. This may
3637be desirable for breakpoints that are to print a specific message and
3638then continue. If none of the remaining commands print anything, you
3639see no sign that the breakpoint was reached. @code{silent} is
3640meaningful only at the beginning of a breakpoint command list.
3641
3642The commands @code{echo}, @code{output}, and @code{printf} allow you to
3643print precisely controlled output, and are often useful in silent
3644breakpoints. @xref{Output, ,Commands for controlled output}.
3645
3646For example, here is how you could use breakpoint commands to print the
3647value of @code{x} at entry to @code{foo} whenever @code{x} is positive.
3648
474c8240 3649@smallexample
c906108c
SS
3650break foo if x>0
3651commands
3652silent
3653printf "x is %d\n",x
3654cont
3655end
474c8240 3656@end smallexample
c906108c
SS
3657
3658One application for breakpoint commands is to compensate for one bug so
3659you can test for another. Put a breakpoint just after the erroneous line
3660of code, give it a condition to detect the case in which something
3661erroneous has been done, and give it commands to assign correct values
3662to any variables that need them. End with the @code{continue} command
3663so that your program does not stop, and start with the @code{silent}
3664command so that no output is produced. Here is an example:
3665
474c8240 3666@smallexample
c906108c
SS
3667break 403
3668commands
3669silent
3670set x = y + 4
3671cont
3672end
474c8240 3673@end smallexample
c906108c 3674
6d2ebf8b 3675@node Breakpoint Menus
c906108c
SS
3676@subsection Breakpoint menus
3677@cindex overloading
3678@cindex symbol overloading
3679
b383017d 3680Some programming languages (notably C@t{++} and Objective-C) permit a
b37303ee 3681single function name
c906108c
SS
3682to be defined several times, for application in different contexts.
3683This is called @dfn{overloading}. When a function name is overloaded,
3684@samp{break @var{function}} is not enough to tell @value{GDBN} where you want
3685a breakpoint. If you realize this is a problem, you can use
3686something like @samp{break @var{function}(@var{types})} to specify which
3687particular version of the function you want. Otherwise, @value{GDBN} offers
3688you a menu of numbered choices for different possible breakpoints, and
3689waits for your selection with the prompt @samp{>}. The first two
3690options are always @samp{[0] cancel} and @samp{[1] all}. Typing @kbd{1}
3691sets a breakpoint at each definition of @var{function}, and typing
3692@kbd{0} aborts the @code{break} command without setting any new
3693breakpoints.
3694
3695For example, the following session excerpt shows an attempt to set a
3696breakpoint at the overloaded symbol @code{String::after}.
3697We choose three particular definitions of that function name:
3698
3699@c FIXME! This is likely to change to show arg type lists, at least
3700@smallexample
3701@group
3702(@value{GDBP}) b String::after
3703[0] cancel
3704[1] all
3705[2] file:String.cc; line number:867
3706[3] file:String.cc; line number:860
3707[4] file:String.cc; line number:875
3708[5] file:String.cc; line number:853
3709[6] file:String.cc; line number:846
3710[7] file:String.cc; line number:735
3711> 2 4 6
3712Breakpoint 1 at 0xb26c: file String.cc, line 867.
3713Breakpoint 2 at 0xb344: file String.cc, line 875.
3714Breakpoint 3 at 0xafcc: file String.cc, line 846.
3715Multiple breakpoints were set.
3716Use the "delete" command to delete unwanted
3717 breakpoints.
3718(@value{GDBP})
3719@end group
3720@end smallexample
c906108c
SS
3721
3722@c @ifclear BARETARGET
6d2ebf8b 3723@node Error in Breakpoints
d4f3574e 3724@subsection ``Cannot insert breakpoints''
c906108c
SS
3725@c
3726@c FIXME!! 14/6/95 Is there a real example of this? Let's use it.
3727@c
d4f3574e
SS
3728Under some operating systems, breakpoints cannot be used in a program if
3729any other process is running that program. In this situation,
5d161b24 3730attempting to run or continue a program with a breakpoint causes
d4f3574e
SS
3731@value{GDBN} to print an error message:
3732
474c8240 3733@smallexample
d4f3574e
SS
3734Cannot insert breakpoints.
3735The same program may be running in another process.
474c8240 3736@end smallexample
d4f3574e
SS
3737
3738When this happens, you have three ways to proceed:
3739
3740@enumerate
3741@item
3742Remove or disable the breakpoints, then continue.
3743
3744@item
5d161b24 3745Suspend @value{GDBN}, and copy the file containing your program to a new
d4f3574e 3746name. Resume @value{GDBN} and use the @code{exec-file} command to specify
5d161b24 3747that @value{GDBN} should run your program under that name.
d4f3574e
SS
3748Then start your program again.
3749
3750@item
3751Relink your program so that the text segment is nonsharable, using the
3752linker option @samp{-N}. The operating system limitation may not apply
3753to nonsharable executables.
3754@end enumerate
c906108c
SS
3755@c @end ifclear
3756
d4f3574e
SS
3757A similar message can be printed if you request too many active
3758hardware-assisted breakpoints and watchpoints:
3759
3760@c FIXME: the precise wording of this message may change; the relevant
3761@c source change is not committed yet (Sep 3, 1999).
3762@smallexample
3763Stopped; cannot insert breakpoints.
3764You may have requested too many hardware breakpoints and watchpoints.
3765@end smallexample
3766
3767@noindent
3768This message is printed when you attempt to resume the program, since
3769only then @value{GDBN} knows exactly how many hardware breakpoints and
3770watchpoints it needs to insert.
3771
3772When this message is printed, you need to disable or remove some of the
3773hardware-assisted breakpoints and watchpoints, and then continue.
3774
1485d690
KB
3775@node Breakpoint related warnings
3776@subsection ``Breakpoint address adjusted...''
3777@cindex breakpoint address adjusted
3778
3779Some processor architectures place constraints on the addresses at
3780which breakpoints may be placed. For architectures thus constrained,
3781@value{GDBN} will attempt to adjust the breakpoint's address to comply
3782with the constraints dictated by the architecture.
3783
3784One example of such an architecture is the Fujitsu FR-V. The FR-V is
3785a VLIW architecture in which a number of RISC-like instructions may be
3786bundled together for parallel execution. The FR-V architecture
3787constrains the location of a breakpoint instruction within such a
3788bundle to the instruction with the lowest address. @value{GDBN}
3789honors this constraint by adjusting a breakpoint's address to the
3790first in the bundle.
3791
3792It is not uncommon for optimized code to have bundles which contain
3793instructions from different source statements, thus it may happen that
3794a breakpoint's address will be adjusted from one source statement to
3795another. Since this adjustment may significantly alter @value{GDBN}'s
3796breakpoint related behavior from what the user expects, a warning is
3797printed when the breakpoint is first set and also when the breakpoint
3798is hit.
3799
3800A warning like the one below is printed when setting a breakpoint
3801that's been subject to address adjustment:
3802
3803@smallexample
3804warning: Breakpoint address adjusted from 0x00010414 to 0x00010410.
3805@end smallexample
3806
3807Such warnings are printed both for user settable and @value{GDBN}'s
3808internal breakpoints. If you see one of these warnings, you should
3809verify that a breakpoint set at the adjusted address will have the
3810desired affect. If not, the breakpoint in question may be removed and
b383017d 3811other breakpoints may be set which will have the desired behavior.
1485d690
KB
3812E.g., it may be sufficient to place the breakpoint at a later
3813instruction. A conditional breakpoint may also be useful in some
3814cases to prevent the breakpoint from triggering too often.
3815
3816@value{GDBN} will also issue a warning when stopping at one of these
3817adjusted breakpoints:
3818
3819@smallexample
3820warning: Breakpoint 1 address previously adjusted from 0x00010414
3821to 0x00010410.
3822@end smallexample
3823
3824When this warning is encountered, it may be too late to take remedial
3825action except in cases where the breakpoint is hit earlier or more
3826frequently than expected.
d4f3574e 3827
6d2ebf8b 3828@node Continuing and Stepping
c906108c
SS
3829@section Continuing and stepping
3830
3831@cindex stepping
3832@cindex continuing
3833@cindex resuming execution
3834@dfn{Continuing} means resuming program execution until your program
3835completes normally. In contrast, @dfn{stepping} means executing just
3836one more ``step'' of your program, where ``step'' may mean either one
3837line of source code, or one machine instruction (depending on what
7a292a7a
SS
3838particular command you use). Either when continuing or when stepping,
3839your program may stop even sooner, due to a breakpoint or a signal. (If
d4f3574e
SS
3840it stops due to a signal, you may want to use @code{handle}, or use
3841@samp{signal 0} to resume execution. @xref{Signals, ,Signals}.)
c906108c
SS
3842
3843@table @code
3844@kindex continue
41afff9a
EZ
3845@kindex c @r{(@code{continue})}
3846@kindex fg @r{(resume foreground execution)}
c906108c
SS
3847@item continue @r{[}@var{ignore-count}@r{]}
3848@itemx c @r{[}@var{ignore-count}@r{]}
3849@itemx fg @r{[}@var{ignore-count}@r{]}
3850Resume program execution, at the address where your program last stopped;
3851any breakpoints set at that address are bypassed. The optional argument
3852@var{ignore-count} allows you to specify a further number of times to
3853ignore a breakpoint at this location; its effect is like that of
3854@code{ignore} (@pxref{Conditions, ,Break conditions}).
3855
3856The argument @var{ignore-count} is meaningful only when your program
3857stopped due to a breakpoint. At other times, the argument to
3858@code{continue} is ignored.
3859
d4f3574e
SS
3860The synonyms @code{c} and @code{fg} (for @dfn{foreground}, as the
3861debugged program is deemed to be the foreground program) are provided
3862purely for convenience, and have exactly the same behavior as
3863@code{continue}.
c906108c
SS
3864@end table
3865
3866To resume execution at a different place, you can use @code{return}
3867(@pxref{Returning, ,Returning from a function}) to go back to the
3868calling function; or @code{jump} (@pxref{Jumping, ,Continuing at a
3869different address}) to go to an arbitrary location in your program.
3870
3871A typical technique for using stepping is to set a breakpoint
3872(@pxref{Breakpoints, ,Breakpoints; watchpoints; and catchpoints}) at the
3873beginning of the function or the section of your program where a problem
3874is believed to lie, run your program until it stops at that breakpoint,
3875and then step through the suspect area, examining the variables that are
3876interesting, until you see the problem happen.
3877
3878@table @code
3879@kindex step
41afff9a 3880@kindex s @r{(@code{step})}
c906108c
SS
3881@item step
3882Continue running your program until control reaches a different source
3883line, then stop it and return control to @value{GDBN}. This command is
3884abbreviated @code{s}.
3885
3886@quotation
3887@c "without debugging information" is imprecise; actually "without line
3888@c numbers in the debugging information". (gcc -g1 has debugging info but
3889@c not line numbers). But it seems complex to try to make that
3890@c distinction here.
3891@emph{Warning:} If you use the @code{step} command while control is
3892within a function that was compiled without debugging information,
3893execution proceeds until control reaches a function that does have
3894debugging information. Likewise, it will not step into a function which
3895is compiled without debugging information. To step through functions
3896without debugging information, use the @code{stepi} command, described
3897below.
3898@end quotation
3899
4a92d011
EZ
3900The @code{step} command only stops at the first instruction of a source
3901line. This prevents the multiple stops that could otherwise occur in
3902@code{switch} statements, @code{for} loops, etc. @code{step} continues
3903to stop if a function that has debugging information is called within
3904the line. In other words, @code{step} @emph{steps inside} any functions
3905called within the line.
c906108c 3906
d4f3574e
SS
3907Also, the @code{step} command only enters a function if there is line
3908number information for the function. Otherwise it acts like the
5d161b24 3909@code{next} command. This avoids problems when using @code{cc -gl}
c906108c 3910on MIPS machines. Previously, @code{step} entered subroutines if there
5d161b24 3911was any debugging information about the routine.
c906108c
SS
3912
3913@item step @var{count}
3914Continue running as in @code{step}, but do so @var{count} times. If a
7a292a7a
SS
3915breakpoint is reached, or a signal not related to stepping occurs before
3916@var{count} steps, stepping stops right away.
c906108c
SS
3917
3918@kindex next
41afff9a 3919@kindex n @r{(@code{next})}
c906108c
SS
3920@item next @r{[}@var{count}@r{]}
3921Continue to the next source line in the current (innermost) stack frame.
7a292a7a
SS
3922This is similar to @code{step}, but function calls that appear within
3923the line of code are executed without stopping. Execution stops when
3924control reaches a different line of code at the original stack level
3925that was executing when you gave the @code{next} command. This command
3926is abbreviated @code{n}.
c906108c
SS
3927
3928An argument @var{count} is a repeat count, as for @code{step}.
3929
3930
3931@c FIX ME!! Do we delete this, or is there a way it fits in with
3932@c the following paragraph? --- Vctoria
3933@c
3934@c @code{next} within a function that lacks debugging information acts like
3935@c @code{step}, but any function calls appearing within the code of the
3936@c function are executed without stopping.
3937
d4f3574e
SS
3938The @code{next} command only stops at the first instruction of a
3939source line. This prevents multiple stops that could otherwise occur in
4a92d011 3940@code{switch} statements, @code{for} loops, etc.
c906108c 3941
b90a5f51
CF
3942@kindex set step-mode
3943@item set step-mode
3944@cindex functions without line info, and stepping
3945@cindex stepping into functions with no line info
3946@itemx set step-mode on
4a92d011 3947The @code{set step-mode on} command causes the @code{step} command to
b90a5f51
CF
3948stop at the first instruction of a function which contains no debug line
3949information rather than stepping over it.
3950
4a92d011
EZ
3951This is useful in cases where you may be interested in inspecting the
3952machine instructions of a function which has no symbolic info and do not
3953want @value{GDBN} to automatically skip over this function.
b90a5f51
CF
3954
3955@item set step-mode off
4a92d011 3956Causes the @code{step} command to step over any functions which contains no
b90a5f51
CF
3957debug information. This is the default.
3958
9c16f35a
EZ
3959@item show step-mode
3960Show whether @value{GDBN} will stop in or step over functions without
3961source line debug information.
3962
c906108c
SS
3963@kindex finish
3964@item finish
3965Continue running until just after function in the selected stack frame
3966returns. Print the returned value (if any).
3967
3968Contrast this with the @code{return} command (@pxref{Returning,
3969,Returning from a function}).
3970
3971@kindex until
41afff9a 3972@kindex u @r{(@code{until})}
09d4efe1 3973@cindex run until specified location
c906108c
SS
3974@item until
3975@itemx u
3976Continue running until a source line past the current line, in the
3977current stack frame, is reached. This command is used to avoid single
3978stepping through a loop more than once. It is like the @code{next}
3979command, except that when @code{until} encounters a jump, it
3980automatically continues execution until the program counter is greater
3981than the address of the jump.
3982
3983This means that when you reach the end of a loop after single stepping
3984though it, @code{until} makes your program continue execution until it
3985exits the loop. In contrast, a @code{next} command at the end of a loop
3986simply steps back to the beginning of the loop, which forces you to step
3987through the next iteration.
3988
3989@code{until} always stops your program if it attempts to exit the current
3990stack frame.
3991
3992@code{until} may produce somewhat counterintuitive results if the order
3993of machine code does not match the order of the source lines. For
3994example, in the following excerpt from a debugging session, the @code{f}
3995(@code{frame}) command shows that execution is stopped at line
3996@code{206}; yet when we use @code{until}, we get to line @code{195}:
3997
474c8240 3998@smallexample
c906108c
SS
3999(@value{GDBP}) f
4000#0 main (argc=4, argv=0xf7fffae8) at m4.c:206
4001206 expand_input();
4002(@value{GDBP}) until
4003195 for ( ; argc > 0; NEXTARG) @{
474c8240 4004@end smallexample
c906108c
SS
4005
4006This happened because, for execution efficiency, the compiler had
4007generated code for the loop closure test at the end, rather than the
4008start, of the loop---even though the test in a C @code{for}-loop is
4009written before the body of the loop. The @code{until} command appeared
4010to step back to the beginning of the loop when it advanced to this
4011expression; however, it has not really gone to an earlier
4012statement---not in terms of the actual machine code.
4013
4014@code{until} with no argument works by means of single
4015instruction stepping, and hence is slower than @code{until} with an
4016argument.
4017
4018@item until @var{location}
4019@itemx u @var{location}
4020Continue running your program until either the specified location is
4021reached, or the current stack frame returns. @var{location} is any of
4022the forms of argument acceptable to @code{break} (@pxref{Set Breaks,
c60eb6f1
EZ
4023,Setting breakpoints}). This form of the command uses breakpoints, and
4024hence is quicker than @code{until} without an argument. The specified
4025location is actually reached only if it is in the current frame. This
4026implies that @code{until} can be used to skip over recursive function
4027invocations. For instance in the code below, if the current location is
4028line @code{96}, issuing @code{until 99} will execute the program up to
4029line @code{99} in the same invocation of factorial, i.e. after the inner
4030invocations have returned.
4031
4032@smallexample
403394 int factorial (int value)
403495 @{
403596 if (value > 1) @{
403697 value *= factorial (value - 1);
403798 @}
403899 return (value);
4039100 @}
4040@end smallexample
4041
4042
4043@kindex advance @var{location}
4044@itemx advance @var{location}
09d4efe1
EZ
4045Continue running the program up to the given @var{location}. An argument is
4046required, which should be of the same form as arguments for the @code{break}
c60eb6f1
EZ
4047command. Execution will also stop upon exit from the current stack
4048frame. This command is similar to @code{until}, but @code{advance} will
4049not skip over recursive function calls, and the target location doesn't
4050have to be in the same frame as the current one.
4051
c906108c
SS
4052
4053@kindex stepi
41afff9a 4054@kindex si @r{(@code{stepi})}
c906108c 4055@item stepi
96a2c332 4056@itemx stepi @var{arg}
c906108c
SS
4057@itemx si
4058Execute one machine instruction, then stop and return to the debugger.
4059
4060It is often useful to do @samp{display/i $pc} when stepping by machine
4061instructions. This makes @value{GDBN} automatically display the next
4062instruction to be executed, each time your program stops. @xref{Auto
4063Display,, Automatic display}.
4064
4065An argument is a repeat count, as in @code{step}.
4066
4067@need 750
4068@kindex nexti
41afff9a 4069@kindex ni @r{(@code{nexti})}
c906108c 4070@item nexti
96a2c332 4071@itemx nexti @var{arg}
c906108c
SS
4072@itemx ni
4073Execute one machine instruction, but if it is a function call,
4074proceed until the function returns.
4075
4076An argument is a repeat count, as in @code{next}.
4077@end table
4078
6d2ebf8b 4079@node Signals
c906108c
SS
4080@section Signals
4081@cindex signals
4082
4083A signal is an asynchronous event that can happen in a program. The
4084operating system defines the possible kinds of signals, and gives each
4085kind a name and a number. For example, in Unix @code{SIGINT} is the
d4f3574e 4086signal a program gets when you type an interrupt character (often @kbd{C-c});
c906108c
SS
4087@code{SIGSEGV} is the signal a program gets from referencing a place in
4088memory far away from all the areas in use; @code{SIGALRM} occurs when
4089the alarm clock timer goes off (which happens only if your program has
4090requested an alarm).
4091
4092@cindex fatal signals
4093Some signals, including @code{SIGALRM}, are a normal part of the
4094functioning of your program. Others, such as @code{SIGSEGV}, indicate
d4f3574e 4095errors; these signals are @dfn{fatal} (they kill your program immediately) if the
c906108c
SS
4096program has not specified in advance some other way to handle the signal.
4097@code{SIGINT} does not indicate an error in your program, but it is normally
4098fatal so it can carry out the purpose of the interrupt: to kill the program.
4099
4100@value{GDBN} has the ability to detect any occurrence of a signal in your
4101program. You can tell @value{GDBN} in advance what to do for each kind of
4102signal.
4103
4104@cindex handling signals
24f93129
EZ
4105Normally, @value{GDBN} is set up to let the non-erroneous signals like
4106@code{SIGALRM} be silently passed to your program
4107(so as not to interfere with their role in the program's functioning)
c906108c
SS
4108but to stop your program immediately whenever an error signal happens.
4109You can change these settings with the @code{handle} command.
4110
4111@table @code
4112@kindex info signals
09d4efe1 4113@kindex info handle
c906108c 4114@item info signals
96a2c332 4115@itemx info handle
c906108c
SS
4116Print a table of all the kinds of signals and how @value{GDBN} has been told to
4117handle each one. You can use this to see the signal numbers of all
4118the defined types of signals.
4119
d4f3574e 4120@code{info handle} is an alias for @code{info signals}.
c906108c
SS
4121
4122@kindex handle
4123@item handle @var{signal} @var{keywords}@dots{}
5ece1a18
EZ
4124Change the way @value{GDBN} handles signal @var{signal}. @var{signal}
4125can be the number of a signal or its name (with or without the
24f93129 4126@samp{SIG} at the beginning); a list of signal numbers of the form
5ece1a18
EZ
4127@samp{@var{low}-@var{high}}; or the word @samp{all}, meaning all the
4128known signals. The @var{keywords} say what change to make.
c906108c
SS
4129@end table
4130
4131@c @group
4132The keywords allowed by the @code{handle} command can be abbreviated.
4133Their full names are:
4134
4135@table @code
4136@item nostop
4137@value{GDBN} should not stop your program when this signal happens. It may
4138still print a message telling you that the signal has come in.
4139
4140@item stop
4141@value{GDBN} should stop your program when this signal happens. This implies
4142the @code{print} keyword as well.
4143
4144@item print
4145@value{GDBN} should print a message when this signal happens.
4146
4147@item noprint
4148@value{GDBN} should not mention the occurrence of the signal at all. This
4149implies the @code{nostop} keyword as well.
4150
4151@item pass
5ece1a18 4152@itemx noignore
c906108c
SS
4153@value{GDBN} should allow your program to see this signal; your program
4154can handle the signal, or else it may terminate if the signal is fatal
5ece1a18 4155and not handled. @code{pass} and @code{noignore} are synonyms.
c906108c
SS
4156
4157@item nopass
5ece1a18 4158@itemx ignore
c906108c 4159@value{GDBN} should not allow your program to see this signal.
5ece1a18 4160@code{nopass} and @code{ignore} are synonyms.
c906108c
SS
4161@end table
4162@c @end group
4163
d4f3574e
SS
4164When a signal stops your program, the signal is not visible to the
4165program until you
c906108c
SS
4166continue. Your program sees the signal then, if @code{pass} is in
4167effect for the signal in question @emph{at that time}. In other words,
4168after @value{GDBN} reports a signal, you can use the @code{handle}
4169command with @code{pass} or @code{nopass} to control whether your
4170program sees that signal when you continue.
4171
24f93129
EZ
4172The default is set to @code{nostop}, @code{noprint}, @code{pass} for
4173non-erroneous signals such as @code{SIGALRM}, @code{SIGWINCH} and
4174@code{SIGCHLD}, and to @code{stop}, @code{print}, @code{pass} for the
4175erroneous signals.
4176
c906108c
SS
4177You can also use the @code{signal} command to prevent your program from
4178seeing a signal, or cause it to see a signal it normally would not see,
4179or to give it any signal at any time. For example, if your program stopped
4180due to some sort of memory reference error, you might store correct
4181values into the erroneous variables and continue, hoping to see more
4182execution; but your program would probably terminate immediately as
4183a result of the fatal signal once it saw the signal. To prevent this,
4184you can continue with @samp{signal 0}. @xref{Signaling, ,Giving your
5d161b24 4185program a signal}.
c906108c 4186
6d2ebf8b 4187@node Thread Stops
c906108c
SS
4188@section Stopping and starting multi-thread programs
4189
4190When your program has multiple threads (@pxref{Threads,, Debugging
4191programs with multiple threads}), you can choose whether to set
4192breakpoints on all threads, or on a particular thread.
4193
4194@table @code
4195@cindex breakpoints and threads
4196@cindex thread breakpoints
4197@kindex break @dots{} thread @var{threadno}
4198@item break @var{linespec} thread @var{threadno}
4199@itemx break @var{linespec} thread @var{threadno} if @dots{}
4200@var{linespec} specifies source lines; there are several ways of
4201writing them, but the effect is always to specify some source line.
4202
4203Use the qualifier @samp{thread @var{threadno}} with a breakpoint command
4204to specify that you only want @value{GDBN} to stop the program when a
4205particular thread reaches this breakpoint. @var{threadno} is one of the
4206numeric thread identifiers assigned by @value{GDBN}, shown in the first
4207column of the @samp{info threads} display.
4208
4209If you do not specify @samp{thread @var{threadno}} when you set a
4210breakpoint, the breakpoint applies to @emph{all} threads of your
4211program.
4212
4213You can use the @code{thread} qualifier on conditional breakpoints as
4214well; in this case, place @samp{thread @var{threadno}} before the
4215breakpoint condition, like this:
4216
4217@smallexample
2df3850c 4218(@value{GDBP}) break frik.c:13 thread 28 if bartab > lim
c906108c
SS
4219@end smallexample
4220
4221@end table
4222
4223@cindex stopped threads
4224@cindex threads, stopped
4225Whenever your program stops under @value{GDBN} for any reason,
4226@emph{all} threads of execution stop, not just the current thread. This
4227allows you to examine the overall state of the program, including
4228switching between threads, without worrying that things may change
4229underfoot.
4230
36d86913
MC
4231@cindex thread breakpoints and system calls
4232@cindex system calls and thread breakpoints
4233@cindex premature return from system calls
4234There is an unfortunate side effect. If one thread stops for a
4235breakpoint, or for some other reason, and another thread is blocked in a
4236system call, then the system call may return prematurely. This is a
4237consequence of the interaction between multiple threads and the signals
4238that @value{GDBN} uses to implement breakpoints and other events that
4239stop execution.
4240
4241To handle this problem, your program should check the return value of
4242each system call and react appropriately. This is good programming
4243style anyways.
4244
4245For example, do not write code like this:
4246
4247@smallexample
4248 sleep (10);
4249@end smallexample
4250
4251The call to @code{sleep} will return early if a different thread stops
4252at a breakpoint or for some other reason.
4253
4254Instead, write this:
4255
4256@smallexample
4257 int unslept = 10;
4258 while (unslept > 0)
4259 unslept = sleep (unslept);
4260@end smallexample
4261
4262A system call is allowed to return early, so the system is still
4263conforming to its specification. But @value{GDBN} does cause your
4264multi-threaded program to behave differently than it would without
4265@value{GDBN}.
4266
4267Also, @value{GDBN} uses internal breakpoints in the thread library to
4268monitor certain events such as thread creation and thread destruction.
4269When such an event happens, a system call in another thread may return
4270prematurely, even though your program does not appear to stop.
4271
c906108c
SS
4272@cindex continuing threads
4273@cindex threads, continuing
4274Conversely, whenever you restart the program, @emph{all} threads start
4275executing. @emph{This is true even when single-stepping} with commands
5d161b24 4276like @code{step} or @code{next}.
c906108c
SS
4277
4278In particular, @value{GDBN} cannot single-step all threads in lockstep.
4279Since thread scheduling is up to your debugging target's operating
4280system (not controlled by @value{GDBN}), other threads may
4281execute more than one statement while the current thread completes a
4282single step. Moreover, in general other threads stop in the middle of a
4283statement, rather than at a clean statement boundary, when the program
4284stops.
4285
4286You might even find your program stopped in another thread after
4287continuing or even single-stepping. This happens whenever some other
4288thread runs into a breakpoint, a signal, or an exception before the
4289first thread completes whatever you requested.
4290
4291On some OSes, you can lock the OS scheduler and thus allow only a single
4292thread to run.
4293
4294@table @code
4295@item set scheduler-locking @var{mode}
9c16f35a
EZ
4296@cindex scheduler locking mode
4297@cindex lock scheduler
c906108c
SS
4298Set the scheduler locking mode. If it is @code{off}, then there is no
4299locking and any thread may run at any time. If @code{on}, then only the
4300current thread may run when the inferior is resumed. The @code{step}
4301mode optimizes for single-stepping. It stops other threads from
4302``seizing the prompt'' by preempting the current thread while you are
4303stepping. Other threads will only rarely (or never) get a chance to run
d4f3574e 4304when you step. They are more likely to run when you @samp{next} over a
c906108c 4305function call, and they are completely free to run when you use commands
d4f3574e 4306like @samp{continue}, @samp{until}, or @samp{finish}. However, unless another
c906108c 4307thread hits a breakpoint during its timeslice, they will never steal the
2df3850c 4308@value{GDBN} prompt away from the thread that you are debugging.
c906108c
SS
4309
4310@item show scheduler-locking
4311Display the current scheduler locking mode.
4312@end table
4313
c906108c 4314
6d2ebf8b 4315@node Stack
c906108c
SS
4316@chapter Examining the Stack
4317
4318When your program has stopped, the first thing you need to know is where it
4319stopped and how it got there.
4320
4321@cindex call stack
5d161b24
DB
4322Each time your program performs a function call, information about the call
4323is generated.
4324That information includes the location of the call in your program,
4325the arguments of the call,
c906108c 4326and the local variables of the function being called.
5d161b24 4327The information is saved in a block of data called a @dfn{stack frame}.
c906108c
SS
4328The stack frames are allocated in a region of memory called the @dfn{call
4329stack}.
4330
4331When your program stops, the @value{GDBN} commands for examining the
4332stack allow you to see all of this information.
4333
4334@cindex selected frame
4335One of the stack frames is @dfn{selected} by @value{GDBN} and many
4336@value{GDBN} commands refer implicitly to the selected frame. In
4337particular, whenever you ask @value{GDBN} for the value of a variable in
4338your program, the value is found in the selected frame. There are
4339special @value{GDBN} commands to select whichever frame you are
4340interested in. @xref{Selection, ,Selecting a frame}.
4341
4342When your program stops, @value{GDBN} automatically selects the
5d161b24 4343currently executing frame and describes it briefly, similar to the
c906108c
SS
4344@code{frame} command (@pxref{Frame Info, ,Information about a frame}).
4345
4346@menu
4347* Frames:: Stack frames
4348* Backtrace:: Backtraces
4349* Selection:: Selecting a frame
4350* Frame Info:: Information on a frame
c906108c
SS
4351
4352@end menu
4353
6d2ebf8b 4354@node Frames
c906108c
SS
4355@section Stack frames
4356
d4f3574e 4357@cindex frame, definition
c906108c
SS
4358@cindex stack frame
4359The call stack is divided up into contiguous pieces called @dfn{stack
4360frames}, or @dfn{frames} for short; each frame is the data associated
4361with one call to one function. The frame contains the arguments given
4362to the function, the function's local variables, and the address at
4363which the function is executing.
4364
4365@cindex initial frame
4366@cindex outermost frame
4367@cindex innermost frame
4368When your program is started, the stack has only one frame, that of the
4369function @code{main}. This is called the @dfn{initial} frame or the
4370@dfn{outermost} frame. Each time a function is called, a new frame is
4371made. Each time a function returns, the frame for that function invocation
4372is eliminated. If a function is recursive, there can be many frames for
4373the same function. The frame for the function in which execution is
4374actually occurring is called the @dfn{innermost} frame. This is the most
4375recently created of all the stack frames that still exist.
4376
4377@cindex frame pointer
4378Inside your program, stack frames are identified by their addresses. A
4379stack frame consists of many bytes, each of which has its own address; each
4380kind of computer has a convention for choosing one byte whose
4381address serves as the address of the frame. Usually this address is kept
e09f16f9
EZ
4382in a register called the @dfn{frame pointer register}
4383(@pxref{Registers, $fp}) while execution is going on in that frame.
c906108c
SS
4384
4385@cindex frame number
4386@value{GDBN} assigns numbers to all existing stack frames, starting with
4387zero for the innermost frame, one for the frame that called it,
4388and so on upward. These numbers do not really exist in your program;
4389they are assigned by @value{GDBN} to give you a way of designating stack
4390frames in @value{GDBN} commands.
4391
6d2ebf8b
SS
4392@c The -fomit-frame-pointer below perennially causes hbox overflow
4393@c underflow problems.
c906108c
SS
4394@cindex frameless execution
4395Some compilers provide a way to compile functions so that they operate
6d2ebf8b 4396without stack frames. (For example, the @value{GCC} option
474c8240 4397@smallexample
6d2ebf8b 4398@samp{-fomit-frame-pointer}
474c8240 4399@end smallexample
6d2ebf8b 4400generates functions without a frame.)
c906108c
SS
4401This is occasionally done with heavily used library functions to save
4402the frame setup time. @value{GDBN} has limited facilities for dealing
4403with these function invocations. If the innermost function invocation
4404has no stack frame, @value{GDBN} nevertheless regards it as though
4405it had a separate frame, which is numbered zero as usual, allowing
4406correct tracing of the function call chain. However, @value{GDBN} has
4407no provision for frameless functions elsewhere in the stack.
4408
4409@table @code
d4f3574e 4410@kindex frame@r{, command}
41afff9a 4411@cindex current stack frame
c906108c 4412@item frame @var{args}
5d161b24 4413The @code{frame} command allows you to move from one stack frame to another,
c906108c 4414and to print the stack frame you select. @var{args} may be either the
5d161b24
DB
4415address of the frame or the stack frame number. Without an argument,
4416@code{frame} prints the current stack frame.
c906108c
SS
4417
4418@kindex select-frame
41afff9a 4419@cindex selecting frame silently
c906108c
SS
4420@item select-frame
4421The @code{select-frame} command allows you to move from one stack frame
4422to another without printing the frame. This is the silent version of
4423@code{frame}.
4424@end table
4425
6d2ebf8b 4426@node Backtrace
c906108c
SS
4427@section Backtraces
4428
09d4efe1
EZ
4429@cindex traceback
4430@cindex call stack traces
c906108c
SS
4431A backtrace is a summary of how your program got where it is. It shows one
4432line per frame, for many frames, starting with the currently executing
4433frame (frame zero), followed by its caller (frame one), and on up the
4434stack.
4435
4436@table @code
4437@kindex backtrace
41afff9a 4438@kindex bt @r{(@code{backtrace})}
c906108c
SS
4439@item backtrace
4440@itemx bt
4441Print a backtrace of the entire stack: one line per frame for all
4442frames in the stack.
4443
4444You can stop the backtrace at any time by typing the system interrupt
4445character, normally @kbd{C-c}.
4446
4447@item backtrace @var{n}
4448@itemx bt @var{n}
4449Similar, but print only the innermost @var{n} frames.
4450
4451@item backtrace -@var{n}
4452@itemx bt -@var{n}
4453Similar, but print only the outermost @var{n} frames.
0f061b69
NR
4454
4455@item backtrace full
4456Print the values of the local variables also.
4457@itemx bt full
c906108c
SS
4458@end table
4459
4460@kindex where
4461@kindex info stack
c906108c
SS
4462The names @code{where} and @code{info stack} (abbreviated @code{info s})
4463are additional aliases for @code{backtrace}.
4464
839c27b7
EZ
4465@cindex multiple threads, backtrace
4466In a multi-threaded program, @value{GDBN} by default shows the
4467backtrace only for the current thread. To display the backtrace for
4468several or all of the threads, use the command @code{thread apply}
4469(@pxref{Threads, thread apply}). For example, if you type @kbd{thread
4470apply all backtrace}, @value{GDBN} will display the backtrace for all
4471the threads; this is handy when you debug a core dump of a
4472multi-threaded program.
4473
c906108c
SS
4474Each line in the backtrace shows the frame number and the function name.
4475The program counter value is also shown---unless you use @code{set
4476print address off}. The backtrace also shows the source file name and
4477line number, as well as the arguments to the function. The program
4478counter value is omitted if it is at the beginning of the code for that
4479line number.
4480
4481Here is an example of a backtrace. It was made with the command
4482@samp{bt 3}, so it shows the innermost three frames.
4483
4484@smallexample
4485@group
5d161b24 4486#0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8)
c906108c
SS
4487 at builtin.c:993
4488#1 0x6e38 in expand_macro (sym=0x2b600) at macro.c:242
4489#2 0x6840 in expand_token (obs=0x0, t=177664, td=0xf7fffb08)
4490 at macro.c:71
4491(More stack frames follow...)
4492@end group
4493@end smallexample
4494
4495@noindent
4496The display for frame zero does not begin with a program counter
4497value, indicating that your program has stopped at the beginning of the
4498code for line @code{993} of @code{builtin.c}.
4499
18999be5
EZ
4500@cindex value optimized out, in backtrace
4501@cindex function call arguments, optimized out
4502If your program was compiled with optimizations, some compilers will
4503optimize away arguments passed to functions if those arguments are
4504never used after the call. Such optimizations generate code that
4505passes arguments through registers, but doesn't store those arguments
4506in the stack frame. @value{GDBN} has no way of displaying such
4507arguments in stack frames other than the innermost one. Here's what
4508such a backtrace might look like:
4509
4510@smallexample
4511@group
4512#0 m4_traceon (obs=0x24eb0, argc=1, argv=0x2b8c8)
4513 at builtin.c:993
4514#1 0x6e38 in expand_macro (sym=<value optimized out>) at macro.c:242
4515#2 0x6840 in expand_token (obs=0x0, t=<value optimized out>, td=0xf7fffb08)
4516 at macro.c:71
4517(More stack frames follow...)
4518@end group
4519@end smallexample
4520
4521@noindent
4522The values of arguments that were not saved in their stack frames are
4523shown as @samp{<value optimized out>}.
4524
4525If you need to display the values of such optimized-out arguments,
4526either deduce that from other variables whose values depend on the one
4527you are interested in, or recompile without optimizations.
4528
a8f24a35
EZ
4529@cindex backtrace beyond @code{main} function
4530@cindex program entry point
4531@cindex startup code, and backtrace
25d29d70
AC
4532Most programs have a standard user entry point---a place where system
4533libraries and startup code transition into user code. For C this is
d416eeec
EZ
4534@code{main}@footnote{
4535Note that embedded programs (the so-called ``free-standing''
4536environment) are not required to have a @code{main} function as the
4537entry point. They could even have multiple entry points.}.
4538When @value{GDBN} finds the entry function in a backtrace
25d29d70
AC
4539it will terminate the backtrace, to avoid tracing into highly
4540system-specific (and generally uninteresting) code.
4541
4542If you need to examine the startup code, or limit the number of levels
4543in a backtrace, you can change this behavior:
95f90d25
DJ
4544
4545@table @code
25d29d70
AC
4546@item set backtrace past-main
4547@itemx set backtrace past-main on
4644b6e3 4548@kindex set backtrace
25d29d70
AC
4549Backtraces will continue past the user entry point.
4550
4551@item set backtrace past-main off
95f90d25
DJ
4552Backtraces will stop when they encounter the user entry point. This is the
4553default.
4554
25d29d70 4555@item show backtrace past-main
4644b6e3 4556@kindex show backtrace
25d29d70
AC
4557Display the current user entry point backtrace policy.
4558
2315ffec
RC
4559@item set backtrace past-entry
4560@itemx set backtrace past-entry on
a8f24a35 4561Backtraces will continue past the internal entry point of an application.
2315ffec
RC
4562This entry point is encoded by the linker when the application is built,
4563and is likely before the user entry point @code{main} (or equivalent) is called.
4564
4565@item set backtrace past-entry off
4566Backtraces will stop when they encouter the internal entry point of an
4567application. This is the default.
4568
4569@item show backtrace past-entry
4570Display the current internal entry point backtrace policy.
4571
25d29d70
AC
4572@item set backtrace limit @var{n}
4573@itemx set backtrace limit 0
4574@cindex backtrace limit
4575Limit the backtrace to @var{n} levels. A value of zero means
4576unlimited.
95f90d25 4577
25d29d70
AC
4578@item show backtrace limit
4579Display the current limit on backtrace levels.
95f90d25
DJ
4580@end table
4581
6d2ebf8b 4582@node Selection
c906108c
SS
4583@section Selecting a frame
4584
4585Most commands for examining the stack and other data in your program work on
4586whichever stack frame is selected at the moment. Here are the commands for
4587selecting a stack frame; all of them finish by printing a brief description
4588of the stack frame just selected.
4589
4590@table @code
d4f3574e 4591@kindex frame@r{, selecting}
41afff9a 4592@kindex f @r{(@code{frame})}
c906108c
SS
4593@item frame @var{n}
4594@itemx f @var{n}
4595Select frame number @var{n}. Recall that frame zero is the innermost
4596(currently executing) frame, frame one is the frame that called the
4597innermost one, and so on. The highest-numbered frame is the one for
4598@code{main}.
4599
4600@item frame @var{addr}
4601@itemx f @var{addr}
4602Select the frame at address @var{addr}. This is useful mainly if the
4603chaining of stack frames has been damaged by a bug, making it
4604impossible for @value{GDBN} to assign numbers properly to all frames. In
4605addition, this can be useful when your program has multiple stacks and
4606switches between them.
4607
c906108c
SS
4608On the SPARC architecture, @code{frame} needs two addresses to
4609select an arbitrary frame: a frame pointer and a stack pointer.
4610
4611On the MIPS and Alpha architecture, it needs two addresses: a stack
4612pointer and a program counter.
4613
4614On the 29k architecture, it needs three addresses: a register stack
4615pointer, a program counter, and a memory stack pointer.
c906108c
SS
4616
4617@kindex up
4618@item up @var{n}
4619Move @var{n} frames up the stack. For positive numbers @var{n}, this
4620advances toward the outermost frame, to higher frame numbers, to frames
4621that have existed longer. @var{n} defaults to one.
4622
4623@kindex down
41afff9a 4624@kindex do @r{(@code{down})}
c906108c
SS
4625@item down @var{n}
4626Move @var{n} frames down the stack. For positive numbers @var{n}, this
4627advances toward the innermost frame, to lower frame numbers, to frames
4628that were created more recently. @var{n} defaults to one. You may
4629abbreviate @code{down} as @code{do}.
4630@end table
4631
4632All of these commands end by printing two lines of output describing the
4633frame. The first line shows the frame number, the function name, the
4634arguments, and the source file and line number of execution in that
5d161b24 4635frame. The second line shows the text of that source line.
c906108c
SS
4636
4637@need 1000
4638For example:
4639
4640@smallexample
4641@group
4642(@value{GDBP}) up
4643#1 0x22f0 in main (argc=1, argv=0xf7fffbf4, env=0xf7fffbfc)
4644 at env.c:10
464510 read_input_file (argv[i]);
4646@end group
4647@end smallexample
4648
4649After such a printout, the @code{list} command with no arguments
4650prints ten lines centered on the point of execution in the frame.
87885426
FN
4651You can also edit the program at the point of execution with your favorite
4652editing program by typing @code{edit}.
4653@xref{List, ,Printing source lines},
4654for details.
c906108c
SS
4655
4656@table @code
4657@kindex down-silently
4658@kindex up-silently
4659@item up-silently @var{n}
4660@itemx down-silently @var{n}
4661These two commands are variants of @code{up} and @code{down},
4662respectively; they differ in that they do their work silently, without
4663causing display of the new frame. They are intended primarily for use
4664in @value{GDBN} command scripts, where the output might be unnecessary and
4665distracting.
4666@end table
4667
6d2ebf8b 4668@node Frame Info
c906108c
SS
4669@section Information about a frame
4670
4671There are several other commands to print information about the selected
4672stack frame.
4673
4674@table @code
4675@item frame
4676@itemx f
4677When used without any argument, this command does not change which
4678frame is selected, but prints a brief description of the currently
4679selected stack frame. It can be abbreviated @code{f}. With an
4680argument, this command is used to select a stack frame.
4681@xref{Selection, ,Selecting a frame}.
4682
4683@kindex info frame
41afff9a 4684@kindex info f @r{(@code{info frame})}
c906108c
SS
4685@item info frame
4686@itemx info f
4687This command prints a verbose description of the selected stack frame,
4688including:
4689
4690@itemize @bullet
5d161b24
DB
4691@item
4692the address of the frame
c906108c
SS
4693@item
4694the address of the next frame down (called by this frame)
4695@item
4696the address of the next frame up (caller of this frame)
4697@item
4698the language in which the source code corresponding to this frame is written
4699@item
4700the address of the frame's arguments
4701@item
d4f3574e
SS
4702the address of the frame's local variables
4703@item
c906108c
SS
4704the program counter saved in it (the address of execution in the caller frame)
4705@item
4706which registers were saved in the frame
4707@end itemize
4708
4709@noindent The verbose description is useful when
4710something has gone wrong that has made the stack format fail to fit
4711the usual conventions.
4712
4713@item info frame @var{addr}
4714@itemx info f @var{addr}
4715Print a verbose description of the frame at address @var{addr}, without
4716selecting that frame. The selected frame remains unchanged by this
4717command. This requires the same kind of address (more than one for some
4718architectures) that you specify in the @code{frame} command.
4719@xref{Selection, ,Selecting a frame}.
4720
4721@kindex info args
4722@item info args
4723Print the arguments of the selected frame, each on a separate line.
4724
4725@item info locals
4726@kindex info locals
4727Print the local variables of the selected frame, each on a separate
4728line. These are all variables (declared either static or automatic)
4729accessible at the point of execution of the selected frame.
4730
c906108c 4731@kindex info catch
d4f3574e
SS
4732@cindex catch exceptions, list active handlers
4733@cindex exception handlers, how to list
c906108c
SS
4734@item info catch
4735Print a list of all the exception handlers that are active in the
4736current stack frame at the current point of execution. To see other
4737exception handlers, visit the associated frame (using the @code{up},
4738@code{down}, or @code{frame} commands); then type @code{info catch}.
4739@xref{Set Catchpoints, , Setting catchpoints}.
53a5351d 4740
c906108c
SS
4741@end table
4742
c906108c 4743
6d2ebf8b 4744@node Source
c906108c
SS
4745@chapter Examining Source Files
4746
4747@value{GDBN} can print parts of your program's source, since the debugging
4748information recorded in the program tells @value{GDBN} what source files were
4749used to build it. When your program stops, @value{GDBN} spontaneously prints
4750the line where it stopped. Likewise, when you select a stack frame
4751(@pxref{Selection, ,Selecting a frame}), @value{GDBN} prints the line where
4752execution in that frame has stopped. You can print other portions of
4753source files by explicit command.
4754
7a292a7a 4755If you use @value{GDBN} through its @sc{gnu} Emacs interface, you may
d4f3574e 4756prefer to use Emacs facilities to view source; see @ref{Emacs, ,Using
7a292a7a 4757@value{GDBN} under @sc{gnu} Emacs}.
c906108c
SS
4758
4759@menu
4760* List:: Printing source lines
87885426 4761* Edit:: Editing source files
c906108c 4762* Search:: Searching source files
c906108c
SS
4763* Source Path:: Specifying source directories
4764* Machine Code:: Source and machine code
4765@end menu
4766
6d2ebf8b 4767@node List
c906108c
SS
4768@section Printing source lines
4769
4770@kindex list
41afff9a 4771@kindex l @r{(@code{list})}
c906108c 4772To print lines from a source file, use the @code{list} command
5d161b24 4773(abbreviated @code{l}). By default, ten lines are printed.
c906108c
SS
4774There are several ways to specify what part of the file you want to print.
4775
4776Here are the forms of the @code{list} command most commonly used:
4777
4778@table @code
4779@item list @var{linenum}
4780Print lines centered around line number @var{linenum} in the
4781current source file.
4782
4783@item list @var{function}
4784Print lines centered around the beginning of function
4785@var{function}.
4786
4787@item list
4788Print more lines. If the last lines printed were printed with a
4789@code{list} command, this prints lines following the last lines
4790printed; however, if the last line printed was a solitary line printed
4791as part of displaying a stack frame (@pxref{Stack, ,Examining the
4792Stack}), this prints lines centered around that line.
4793
4794@item list -
4795Print lines just before the lines last printed.
4796@end table
4797
9c16f35a 4798@cindex @code{list}, how many lines to display
c906108c
SS
4799By default, @value{GDBN} prints ten source lines with any of these forms of
4800the @code{list} command. You can change this using @code{set listsize}:
4801
4802@table @code
4803@kindex set listsize
4804@item set listsize @var{count}
4805Make the @code{list} command display @var{count} source lines (unless
4806the @code{list} argument explicitly specifies some other number).
4807
4808@kindex show listsize
4809@item show listsize
4810Display the number of lines that @code{list} prints.
4811@end table
4812
4813Repeating a @code{list} command with @key{RET} discards the argument,
4814so it is equivalent to typing just @code{list}. This is more useful
4815than listing the same lines again. An exception is made for an
4816argument of @samp{-}; that argument is preserved in repetition so that
4817each repetition moves up in the source file.
4818
4819@cindex linespec
4820In general, the @code{list} command expects you to supply zero, one or two
4821@dfn{linespecs}. Linespecs specify source lines; there are several ways
d4f3574e 4822of writing them, but the effect is always to specify some source line.
c906108c
SS
4823Here is a complete description of the possible arguments for @code{list}:
4824
4825@table @code
4826@item list @var{linespec}
4827Print lines centered around the line specified by @var{linespec}.
4828
4829@item list @var{first},@var{last}
4830Print lines from @var{first} to @var{last}. Both arguments are
4831linespecs.
4832
4833@item list ,@var{last}
4834Print lines ending with @var{last}.
4835
4836@item list @var{first},
4837Print lines starting with @var{first}.
4838
4839@item list +
4840Print lines just after the lines last printed.
4841
4842@item list -
4843Print lines just before the lines last printed.
4844
4845@item list
4846As described in the preceding table.
4847@end table
4848
4849Here are the ways of specifying a single source line---all the
4850kinds of linespec.
4851
4852@table @code
4853@item @var{number}
4854Specifies line @var{number} of the current source file.
4855When a @code{list} command has two linespecs, this refers to
4856the same source file as the first linespec.
4857
4858@item +@var{offset}
4859Specifies the line @var{offset} lines after the last line printed.
4860When used as the second linespec in a @code{list} command that has
4861two, this specifies the line @var{offset} lines down from the
4862first linespec.
4863
4864@item -@var{offset}
4865Specifies the line @var{offset} lines before the last line printed.
4866
4867@item @var{filename}:@var{number}
4868Specifies line @var{number} in the source file @var{filename}.
4869
4870@item @var{function}
4871Specifies the line that begins the body of the function @var{function}.
4872For example: in C, this is the line with the open brace.
4873
4874@item @var{filename}:@var{function}
4875Specifies the line of the open-brace that begins the body of the
4876function @var{function} in the file @var{filename}. You only need the
4877file name with a function name to avoid ambiguity when there are
4878identically named functions in different source files.
4879
4880@item *@var{address}
4881Specifies the line containing the program address @var{address}.
4882@var{address} may be any expression.
4883@end table
4884
87885426
FN
4885@node Edit
4886@section Editing source files
4887@cindex editing source files
4888
4889@kindex edit
4890@kindex e @r{(@code{edit})}
4891To edit the lines in a source file, use the @code{edit} command.
4892The editing program of your choice
4893is invoked with the current line set to
4894the active line in the program.
4895Alternatively, there are several ways to specify what part of the file you
4896want to print if you want to see other parts of the program.
4897
4898Here are the forms of the @code{edit} command most commonly used:
4899
4900@table @code
4901@item edit
4902Edit the current source file at the active line number in the program.
4903
4904@item edit @var{number}
4905Edit the current source file with @var{number} as the active line number.
4906
4907@item edit @var{function}
4908Edit the file containing @var{function} at the beginning of its definition.
4909
4910@item edit @var{filename}:@var{number}
4911Specifies line @var{number} in the source file @var{filename}.
4912
4913@item edit @var{filename}:@var{function}
4914Specifies the line that begins the body of the
4915function @var{function} in the file @var{filename}. You only need the
4916file name with a function name to avoid ambiguity when there are
4917identically named functions in different source files.
4918
4919@item edit *@var{address}
4920Specifies the line containing the program address @var{address}.
4921@var{address} may be any expression.
4922@end table
4923
4924@subsection Choosing your editor
4925You can customize @value{GDBN} to use any editor you want
4926@footnote{
4927The only restriction is that your editor (say @code{ex}), recognizes the
4928following command-line syntax:
10998722 4929@smallexample
87885426 4930ex +@var{number} file
10998722 4931@end smallexample
15387254
EZ
4932The optional numeric value +@var{number} specifies the number of the line in
4933the file where to start editing.}.
4934By default, it is @file{@value{EDITOR}}, but you can change this
10998722
AC
4935by setting the environment variable @code{EDITOR} before using
4936@value{GDBN}. For example, to configure @value{GDBN} to use the
4937@code{vi} editor, you could use these commands with the @code{sh} shell:
4938@smallexample
87885426
FN
4939EDITOR=/usr/bin/vi
4940export EDITOR
15387254 4941gdb @dots{}
10998722 4942@end smallexample
87885426 4943or in the @code{csh} shell,
10998722 4944@smallexample
87885426 4945setenv EDITOR /usr/bin/vi
15387254 4946gdb @dots{}
10998722 4947@end smallexample
87885426 4948
6d2ebf8b 4949@node Search
c906108c 4950@section Searching source files
15387254 4951@cindex searching source files
c906108c
SS
4952
4953There are two commands for searching through the current source file for a
4954regular expression.
4955
4956@table @code
4957@kindex search
4958@kindex forward-search
4959@item forward-search @var{regexp}
4960@itemx search @var{regexp}
4961The command @samp{forward-search @var{regexp}} checks each line,
4962starting with the one following the last line listed, for a match for
5d161b24 4963@var{regexp}. It lists the line that is found. You can use the
c906108c
SS
4964synonym @samp{search @var{regexp}} or abbreviate the command name as
4965@code{fo}.
4966
09d4efe1 4967@kindex reverse-search
c906108c
SS
4968@item reverse-search @var{regexp}
4969The command @samp{reverse-search @var{regexp}} checks each line, starting
4970with the one before the last line listed and going backward, for a match
4971for @var{regexp}. It lists the line that is found. You can abbreviate
4972this command as @code{rev}.
4973@end table
c906108c 4974
6d2ebf8b 4975@node Source Path
c906108c
SS
4976@section Specifying source directories
4977
4978@cindex source path
4979@cindex directories for source files
4980Executable programs sometimes do not record the directories of the source
4981files from which they were compiled, just the names. Even when they do,
4982the directories could be moved between the compilation and your debugging
4983session. @value{GDBN} has a list of directories to search for source files;
4984this is called the @dfn{source path}. Each time @value{GDBN} wants a source file,
4985it tries all the directories in the list, in the order they are present
0b66e38c
EZ
4986in the list, until it finds a file with the desired name.
4987
4988For example, suppose an executable references the file
4989@file{/usr/src/foo-1.0/lib/foo.c}, and our source path is
4990@file{/mnt/cross}. The file is first looked up literally; if this
4991fails, @file{/mnt/cross/usr/src/foo-1.0/lib/foo.c} is tried; if this
4992fails, @file{/mnt/cross/foo.c} is opened; if this fails, an error
4993message is printed. @value{GDBN} does not look up the parts of the
4994source file name, such as @file{/mnt/cross/src/foo-1.0/lib/foo.c}.
4995Likewise, the subdirectories of the source path are not searched: if
4996the source path is @file{/mnt/cross}, and the binary refers to
4997@file{foo.c}, @value{GDBN} would not find it under
4998@file{/mnt/cross/usr/src/foo-1.0/lib}.
4999
5000Plain file names, relative file names with leading directories, file
5001names containing dots, etc.@: are all treated as described above; for
5002instance, if the source path is @file{/mnt/cross}, and the source file
5003is recorded as @file{../lib/foo.c}, @value{GDBN} would first try
5004@file{../lib/foo.c}, then @file{/mnt/cross/../lib/foo.c}, and after
5005that---@file{/mnt/cross/foo.c}.
5006
5007Note that the executable search path is @emph{not} used to locate the
5008source files. Neither is the current working directory, unless it
5009happens to be in the source path.
c906108c
SS
5010
5011Whenever you reset or rearrange the source path, @value{GDBN} clears out
5012any information it has cached about where source files are found and where
5013each line is in the file.
5014
5015@kindex directory
5016@kindex dir
d4f3574e
SS
5017When you start @value{GDBN}, its source path includes only @samp{cdir}
5018and @samp{cwd}, in that order.
c906108c
SS
5019To add other directories, use the @code{directory} command.
5020
4b505b12
AS
5021The search path is used to find both program source files and @value{GDBN}
5022script files (read using the @samp{-command} option and @samp{source} command).
5023
c906108c
SS
5024@table @code
5025@item directory @var{dirname} @dots{}
5026@item dir @var{dirname} @dots{}
5027Add directory @var{dirname} to the front of the source path. Several
d4f3574e
SS
5028directory names may be given to this command, separated by @samp{:}
5029(@samp{;} on MS-DOS and MS-Windows, where @samp{:} usually appears as
5030part of absolute file names) or
c906108c
SS
5031whitespace. You may specify a directory that is already in the source
5032path; this moves it forward, so @value{GDBN} searches it sooner.
5033
5034@kindex cdir
5035@kindex cwd
41afff9a
EZ
5036@vindex $cdir@r{, convenience variable}
5037@vindex $cwdr@r{, convenience variable}
c906108c
SS
5038@cindex compilation directory
5039@cindex current directory
5040@cindex working directory
5041@cindex directory, current
5042@cindex directory, compilation
5043You can use the string @samp{$cdir} to refer to the compilation
5044directory (if one is recorded), and @samp{$cwd} to refer to the current
5045working directory. @samp{$cwd} is not the same as @samp{.}---the former
5046tracks the current working directory as it changes during your @value{GDBN}
5047session, while the latter is immediately expanded to the current
5048directory at the time you add an entry to the source path.
5049
5050@item directory
5051Reset the source path to empty again. This requires confirmation.
5052
5053@c RET-repeat for @code{directory} is explicitly disabled, but since
5054@c repeating it would be a no-op we do not say that. (thanks to RMS)
5055
5056@item show directories
5057@kindex show directories
5058Print the source path: show which directories it contains.
5059@end table
5060
5061If your source path is cluttered with directories that are no longer of
5062interest, @value{GDBN} may sometimes cause confusion by finding the wrong
5063versions of source. You can correct the situation as follows:
5064
5065@enumerate
5066@item
5067Use @code{directory} with no argument to reset the source path to empty.
5068
5069@item
5070Use @code{directory} with suitable arguments to reinstall the
5071directories you want in the source path. You can add all the
5072directories in one command.
5073@end enumerate
5074
6d2ebf8b 5075@node Machine Code
c906108c 5076@section Source and machine code
15387254 5077@cindex source line and its code address
c906108c
SS
5078
5079You can use the command @code{info line} to map source lines to program
5080addresses (and vice versa), and the command @code{disassemble} to display
5081a range of addresses as machine instructions. When run under @sc{gnu} Emacs
d4f3574e 5082mode, the @code{info line} command causes the arrow to point to the
5d161b24 5083line specified. Also, @code{info line} prints addresses in symbolic form as
c906108c
SS
5084well as hex.
5085
5086@table @code
5087@kindex info line
5088@item info line @var{linespec}
5089Print the starting and ending addresses of the compiled code for
5090source line @var{linespec}. You can specify source lines in any of
5091the ways understood by the @code{list} command (@pxref{List, ,Printing
5092source lines}).
5093@end table
5094
5095For example, we can use @code{info line} to discover the location of
5096the object code for the first line of function
5097@code{m4_changequote}:
5098
d4f3574e
SS
5099@c FIXME: I think this example should also show the addresses in
5100@c symbolic form, as they usually would be displayed.
c906108c 5101@smallexample
96a2c332 5102(@value{GDBP}) info line m4_changequote
c906108c
SS
5103Line 895 of "builtin.c" starts at pc 0x634c and ends at 0x6350.
5104@end smallexample
5105
5106@noindent
15387254 5107@cindex code address and its source line
c906108c
SS
5108We can also inquire (using @code{*@var{addr}} as the form for
5109@var{linespec}) what source line covers a particular address:
5110@smallexample
5111(@value{GDBP}) info line *0x63ff
5112Line 926 of "builtin.c" starts at pc 0x63e4 and ends at 0x6404.
5113@end smallexample
5114
5115@cindex @code{$_} and @code{info line}
15387254 5116@cindex @code{x} command, default address
41afff9a 5117@kindex x@r{(examine), and} info line
c906108c
SS
5118After @code{info line}, the default address for the @code{x} command
5119is changed to the starting address of the line, so that @samp{x/i} is
5120sufficient to begin examining the machine code (@pxref{Memory,
5121,Examining memory}). Also, this address is saved as the value of the
5122convenience variable @code{$_} (@pxref{Convenience Vars, ,Convenience
5123variables}).
5124
5125@table @code
5126@kindex disassemble
5127@cindex assembly instructions
5128@cindex instructions, assembly
5129@cindex machine instructions
5130@cindex listing machine instructions
5131@item disassemble
5132This specialized command dumps a range of memory as machine
5133instructions. The default memory range is the function surrounding the
5134program counter of the selected frame. A single argument to this
5135command is a program counter value; @value{GDBN} dumps the function
5136surrounding this value. Two arguments specify a range of addresses
5137(first inclusive, second exclusive) to dump.
5138@end table
5139
c906108c
SS
5140The following example shows the disassembly of a range of addresses of
5141HP PA-RISC 2.0 code:
5142
5143@smallexample
5144(@value{GDBP}) disas 0x32c4 0x32e4
5145Dump of assembler code from 0x32c4 to 0x32e4:
51460x32c4 <main+204>: addil 0,dp
51470x32c8 <main+208>: ldw 0x22c(sr0,r1),r26
51480x32cc <main+212>: ldil 0x3000,r31
51490x32d0 <main+216>: ble 0x3f8(sr4,r31)
51500x32d4 <main+220>: ldo 0(r31),rp
51510x32d8 <main+224>: addil -0x800,dp
51520x32dc <main+228>: ldo 0x588(r1),r26
51530x32e0 <main+232>: ldil 0x3000,r31
5154End of assembler dump.
5155@end smallexample
c906108c
SS
5156
5157Some architectures have more than one commonly-used set of instruction
5158mnemonics or other syntax.
5159
76d17f34
EZ
5160For programs that were dynamically linked and use shared libraries,
5161instructions that call functions or branch to locations in the shared
5162libraries might show a seemingly bogus location---it's actually a
5163location of the relocation table. On some architectures, @value{GDBN}
5164might be able to resolve these to actual function names.
5165
c906108c 5166@table @code
d4f3574e 5167@kindex set disassembly-flavor
d4f3574e
SS
5168@cindex Intel disassembly flavor
5169@cindex AT&T disassembly flavor
5170@item set disassembly-flavor @var{instruction-set}
c906108c
SS
5171Select the instruction set to use when disassembling the
5172program via the @code{disassemble} or @code{x/i} commands.
5173
5174Currently this command is only defined for the Intel x86 family. You
d4f3574e
SS
5175can set @var{instruction-set} to either @code{intel} or @code{att}.
5176The default is @code{att}, the AT&T flavor used by default by Unix
5177assemblers for x86-based targets.
9c16f35a
EZ
5178
5179@kindex show disassembly-flavor
5180@item show disassembly-flavor
5181Show the current setting of the disassembly flavor.
c906108c
SS
5182@end table
5183
5184
6d2ebf8b 5185@node Data
c906108c
SS
5186@chapter Examining Data
5187
5188@cindex printing data
5189@cindex examining data
5190@kindex print
5191@kindex inspect
5192@c "inspect" is not quite a synonym if you are using Epoch, which we do not
5193@c document because it is nonstandard... Under Epoch it displays in a
5194@c different window or something like that.
5195The usual way to examine data in your program is with the @code{print}
7a292a7a
SS
5196command (abbreviated @code{p}), or its synonym @code{inspect}. It
5197evaluates and prints the value of an expression of the language your
5198program is written in (@pxref{Languages, ,Using @value{GDBN} with
5199Different Languages}).
c906108c
SS
5200
5201@table @code
d4f3574e
SS
5202@item print @var{expr}
5203@itemx print /@var{f} @var{expr}
5204@var{expr} is an expression (in the source language). By default the
5205value of @var{expr} is printed in a format appropriate to its data type;
c906108c 5206you can choose a different format by specifying @samp{/@var{f}}, where
d4f3574e 5207@var{f} is a letter specifying the format; see @ref{Output Formats,,Output
c906108c
SS
5208formats}.
5209
5210@item print
5211@itemx print /@var{f}
15387254 5212@cindex reprint the last value
d4f3574e 5213If you omit @var{expr}, @value{GDBN} displays the last value again (from the
c906108c
SS
5214@dfn{value history}; @pxref{Value History, ,Value history}). This allows you to
5215conveniently inspect the same value in an alternative format.
5216@end table
5217
5218A more low-level way of examining data is with the @code{x} command.
5219It examines data in memory at a specified address and prints it in a
5220specified format. @xref{Memory, ,Examining memory}.
5221
7a292a7a 5222If you are interested in information about types, or about how the
d4f3574e
SS
5223fields of a struct or a class are declared, use the @code{ptype @var{exp}}
5224command rather than @code{print}. @xref{Symbols, ,Examining the Symbol
7a292a7a 5225Table}.
c906108c
SS
5226
5227@menu
5228* Expressions:: Expressions
5229* Variables:: Program variables
5230* Arrays:: Artificial arrays
5231* Output Formats:: Output formats
5232* Memory:: Examining memory
5233* Auto Display:: Automatic display
5234* Print Settings:: Print settings
5235* Value History:: Value history
5236* Convenience Vars:: Convenience variables
5237* Registers:: Registers
c906108c 5238* Floating Point Hardware:: Floating point hardware
53c69bd7 5239* Vector Unit:: Vector Unit
721c2651 5240* OS Information:: Auxiliary data provided by operating system
29e57380 5241* Memory Region Attributes:: Memory region attributes
16d9dec6 5242* Dump/Restore Files:: Copy between memory and a file
384ee23f 5243* Core File Generation:: Cause a program dump its core
a0eb71c5
KB
5244* Character Sets:: Debugging programs that use a different
5245 character set than GDB does
09d4efe1 5246* Caching Remote Data:: Data caching for remote targets
c906108c
SS
5247@end menu
5248
6d2ebf8b 5249@node Expressions
c906108c
SS
5250@section Expressions
5251
5252@cindex expressions
5253@code{print} and many other @value{GDBN} commands accept an expression and
5254compute its value. Any kind of constant, variable or operator defined
5255by the programming language you are using is valid in an expression in
e2e0bcd1
JB
5256@value{GDBN}. This includes conditional expressions, function calls,
5257casts, and string constants. It also includes preprocessor macros, if
5258you compiled your program to include this information; see
5259@ref{Compilation}.
c906108c 5260
15387254 5261@cindex arrays in expressions
d4f3574e
SS
5262@value{GDBN} supports array constants in expressions input by
5263the user. The syntax is @{@var{element}, @var{element}@dots{}@}. For example,
5d161b24 5264you can use the command @code{print @{1, 2, 3@}} to build up an array in
d4f3574e 5265memory that is @code{malloc}ed in the target program.
c906108c 5266
c906108c
SS
5267Because C is so widespread, most of the expressions shown in examples in
5268this manual are in C. @xref{Languages, , Using @value{GDBN} with Different
5269Languages}, for information on how to use expressions in other
5270languages.
5271
5272In this section, we discuss operators that you can use in @value{GDBN}
5273expressions regardless of your programming language.
5274
15387254 5275@cindex casts, in expressions
c906108c
SS
5276Casts are supported in all languages, not just in C, because it is so
5277useful to cast a number into a pointer in order to examine a structure
5278at that address in memory.
5279@c FIXME: casts supported---Mod2 true?
c906108c
SS
5280
5281@value{GDBN} supports these operators, in addition to those common
5282to programming languages:
5283
5284@table @code
5285@item @@
5286@samp{@@} is a binary operator for treating parts of memory as arrays.
5287@xref{Arrays, ,Artificial arrays}, for more information.
5288
5289@item ::
5290@samp{::} allows you to specify a variable in terms of the file or
5291function where it is defined. @xref{Variables, ,Program variables}.
5292
5293@cindex @{@var{type}@}
5294@cindex type casting memory
5295@cindex memory, viewing as typed object
5296@cindex casts, to view memory
5297@item @{@var{type}@} @var{addr}
5298Refers to an object of type @var{type} stored at address @var{addr} in
5299memory. @var{addr} may be any expression whose value is an integer or
5300pointer (but parentheses are required around binary operators, just as in
5301a cast). This construct is allowed regardless of what kind of data is
5302normally supposed to reside at @var{addr}.
5303@end table
5304
6d2ebf8b 5305@node Variables
c906108c
SS
5306@section Program variables
5307
5308The most common kind of expression to use is the name of a variable
5309in your program.
5310
5311Variables in expressions are understood in the selected stack frame
5312(@pxref{Selection, ,Selecting a frame}); they must be either:
5313
5314@itemize @bullet
5315@item
5316global (or file-static)
5317@end itemize
5318
5d161b24 5319@noindent or
c906108c
SS
5320
5321@itemize @bullet
5322@item
5323visible according to the scope rules of the
5324programming language from the point of execution in that frame
5d161b24 5325@end itemize
c906108c
SS
5326
5327@noindent This means that in the function
5328
474c8240 5329@smallexample
c906108c
SS
5330foo (a)
5331 int a;
5332@{
5333 bar (a);
5334 @{
5335 int b = test ();
5336 bar (b);
5337 @}
5338@}
474c8240 5339@end smallexample
c906108c
SS
5340
5341@noindent
5342you can examine and use the variable @code{a} whenever your program is
5343executing within the function @code{foo}, but you can only use or
5344examine the variable @code{b} while your program is executing inside
5345the block where @code{b} is declared.
5346
5347@cindex variable name conflict
5348There is an exception: you can refer to a variable or function whose
5349scope is a single source file even if the current execution point is not
5350in this file. But it is possible to have more than one such variable or
5351function with the same name (in different source files). If that
5352happens, referring to that name has unpredictable effects. If you wish,
5353you can specify a static variable in a particular function or file,
15387254 5354using the colon-colon (@code{::}) notation:
c906108c 5355
d4f3574e 5356@cindex colon-colon, context for variables/functions
c906108c
SS
5357@iftex
5358@c info cannot cope with a :: index entry, but why deprive hard copy readers?
41afff9a 5359@cindex @code{::}, context for variables/functions
c906108c 5360@end iftex
474c8240 5361@smallexample
c906108c
SS
5362@var{file}::@var{variable}
5363@var{function}::@var{variable}
474c8240 5364@end smallexample
c906108c
SS
5365
5366@noindent
5367Here @var{file} or @var{function} is the name of the context for the
5368static @var{variable}. In the case of file names, you can use quotes to
5369make sure @value{GDBN} parses the file name as a single word---for example,
5370to print a global value of @code{x} defined in @file{f2.c}:
5371
474c8240 5372@smallexample
c906108c 5373(@value{GDBP}) p 'f2.c'::x
474c8240 5374@end smallexample
c906108c 5375
b37052ae 5376@cindex C@t{++} scope resolution
c906108c 5377This use of @samp{::} is very rarely in conflict with the very similar
b37052ae 5378use of the same notation in C@t{++}. @value{GDBN} also supports use of the C@t{++}
c906108c
SS
5379scope resolution operator in @value{GDBN} expressions.
5380@c FIXME: Um, so what happens in one of those rare cases where it's in
5381@c conflict?? --mew
c906108c
SS
5382
5383@cindex wrong values
5384@cindex variable values, wrong
15387254
EZ
5385@cindex function entry/exit, wrong values of variables
5386@cindex optimized code, wrong values of variables
c906108c
SS
5387@quotation
5388@emph{Warning:} Occasionally, a local variable may appear to have the
5389wrong value at certain points in a function---just after entry to a new
5390scope, and just before exit.
5391@end quotation
5392You may see this problem when you are stepping by machine instructions.
5393This is because, on most machines, it takes more than one instruction to
5394set up a stack frame (including local variable definitions); if you are
5395stepping by machine instructions, variables may appear to have the wrong
5396values until the stack frame is completely built. On exit, it usually
5397also takes more than one machine instruction to destroy a stack frame;
5398after you begin stepping through that group of instructions, local
5399variable definitions may be gone.
5400
5401This may also happen when the compiler does significant optimizations.
5402To be sure of always seeing accurate values, turn off all optimization
5403when compiling.
5404
d4f3574e
SS
5405@cindex ``No symbol "foo" in current context''
5406Another possible effect of compiler optimizations is to optimize
5407unused variables out of existence, or assign variables to registers (as
5408opposed to memory addresses). Depending on the support for such cases
5409offered by the debug info format used by the compiler, @value{GDBN}
5410might not be able to display values for such local variables. If that
5411happens, @value{GDBN} will print a message like this:
5412
474c8240 5413@smallexample
d4f3574e 5414No symbol "foo" in current context.
474c8240 5415@end smallexample
d4f3574e
SS
5416
5417To solve such problems, either recompile without optimizations, or use a
5418different debug info format, if the compiler supports several such
15387254 5419formats. For example, @value{NGCC}, the @sc{gnu} C/C@t{++} compiler,
0179ffac
DC
5420usually supports the @option{-gstabs+} option. @option{-gstabs+}
5421produces debug info in a format that is superior to formats such as
5422COFF. You may be able to use DWARF 2 (@option{-gdwarf-2}), which is also
5423an effective form for debug info. @xref{Debugging Options,,Options
5424for Debugging Your Program or @sc{gnu} CC, gcc.info, Using @sc{gnu} CC}.
15387254
EZ
5425@xref{C, , Debugging C++}, for more info about debug info formats
5426that are best suited to C@t{++} programs.
d4f3574e 5427
ab1adacd
EZ
5428If you ask to print an object whose contents are unknown to
5429@value{GDBN}, e.g., because its data type is not completely specified
5430by the debug information, @value{GDBN} will say @samp{<incomplete
5431type>}. @xref{Symbols, incomplete type}, for more about this.
5432
6d2ebf8b 5433@node Arrays
c906108c
SS
5434@section Artificial arrays
5435
5436@cindex artificial array
15387254 5437@cindex arrays
41afff9a 5438@kindex @@@r{, referencing memory as an array}
c906108c
SS
5439It is often useful to print out several successive objects of the
5440same type in memory; a section of an array, or an array of
5441dynamically determined size for which only a pointer exists in the
5442program.
5443
5444You can do this by referring to a contiguous span of memory as an
5445@dfn{artificial array}, using the binary operator @samp{@@}. The left
5446operand of @samp{@@} should be the first element of the desired array
5447and be an individual object. The right operand should be the desired length
5448of the array. The result is an array value whose elements are all of
5449the type of the left argument. The first element is actually the left
5450argument; the second element comes from bytes of memory immediately
5451following those that hold the first element, and so on. Here is an
5452example. If a program says
5453
474c8240 5454@smallexample
c906108c 5455int *array = (int *) malloc (len * sizeof (int));
474c8240 5456@end smallexample
c906108c
SS
5457
5458@noindent
5459you can print the contents of @code{array} with
5460
474c8240 5461@smallexample
c906108c 5462p *array@@len
474c8240 5463@end smallexample
c906108c
SS
5464
5465The left operand of @samp{@@} must reside in memory. Array values made
5466with @samp{@@} in this way behave just like other arrays in terms of
5467subscripting, and are coerced to pointers when used in expressions.
5468Artificial arrays most often appear in expressions via the value history
5469(@pxref{Value History, ,Value history}), after printing one out.
5470
5471Another way to create an artificial array is to use a cast.
5472This re-interprets a value as if it were an array.
5473The value need not be in memory:
474c8240 5474@smallexample
c906108c
SS
5475(@value{GDBP}) p/x (short[2])0x12345678
5476$1 = @{0x1234, 0x5678@}
474c8240 5477@end smallexample
c906108c
SS
5478
5479As a convenience, if you leave the array length out (as in
c3f6f71d 5480@samp{(@var{type}[])@var{value}}) @value{GDBN} calculates the size to fill
c906108c 5481the value (as @samp{sizeof(@var{value})/sizeof(@var{type})}:
474c8240 5482@smallexample
c906108c
SS
5483(@value{GDBP}) p/x (short[])0x12345678
5484$2 = @{0x1234, 0x5678@}
474c8240 5485@end smallexample
c906108c
SS
5486
5487Sometimes the artificial array mechanism is not quite enough; in
5488moderately complex data structures, the elements of interest may not
5489actually be adjacent---for example, if you are interested in the values
5490of pointers in an array. One useful work-around in this situation is
5491to use a convenience variable (@pxref{Convenience Vars, ,Convenience
5492variables}) as a counter in an expression that prints the first
5493interesting value, and then repeat that expression via @key{RET}. For
5494instance, suppose you have an array @code{dtab} of pointers to
5495structures, and you are interested in the values of a field @code{fv}
5496in each structure. Here is an example of what you might type:
5497
474c8240 5498@smallexample
c906108c
SS
5499set $i = 0
5500p dtab[$i++]->fv
5501@key{RET}
5502@key{RET}
5503@dots{}
474c8240 5504@end smallexample
c906108c 5505
6d2ebf8b 5506@node Output Formats
c906108c
SS
5507@section Output formats
5508
5509@cindex formatted output
5510@cindex output formats
5511By default, @value{GDBN} prints a value according to its data type. Sometimes
5512this is not what you want. For example, you might want to print a number
5513in hex, or a pointer in decimal. Or you might want to view data in memory
5514at a certain address as a character string or as an instruction. To do
5515these things, specify an @dfn{output format} when you print a value.
5516
5517The simplest use of output formats is to say how to print a value
5518already computed. This is done by starting the arguments of the
5519@code{print} command with a slash and a format letter. The format
5520letters supported are:
5521
5522@table @code
5523@item x
5524Regard the bits of the value as an integer, and print the integer in
5525hexadecimal.
5526
5527@item d
5528Print as integer in signed decimal.
5529
5530@item u
5531Print as integer in unsigned decimal.
5532
5533@item o
5534Print as integer in octal.
5535
5536@item t
5537Print as integer in binary. The letter @samp{t} stands for ``two''.
5538@footnote{@samp{b} cannot be used because these format letters are also
5539used with the @code{x} command, where @samp{b} stands for ``byte'';
d4f3574e 5540see @ref{Memory,,Examining memory}.}
c906108c
SS
5541
5542@item a
5543@cindex unknown address, locating
3d67e040 5544@cindex locate address
c906108c
SS
5545Print as an address, both absolute in hexadecimal and as an offset from
5546the nearest preceding symbol. You can use this format used to discover
5547where (in what function) an unknown address is located:
5548
474c8240 5549@smallexample
c906108c
SS
5550(@value{GDBP}) p/a 0x54320
5551$3 = 0x54320 <_initialize_vx+396>
474c8240 5552@end smallexample
c906108c 5553
3d67e040
EZ
5554@noindent
5555The command @code{info symbol 0x54320} yields similar results.
5556@xref{Symbols, info symbol}.
5557
c906108c 5558@item c
51274035
EZ
5559Regard as an integer and print it as a character constant. This
5560prints both the numerical value and its character representation. The
5561character representation is replaced with the octal escape @samp{\nnn}
5562for characters outside the 7-bit @sc{ascii} range.
c906108c
SS
5563
5564@item f
5565Regard the bits of the value as a floating point number and print
5566using typical floating point syntax.
5567@end table
5568
5569For example, to print the program counter in hex (@pxref{Registers}), type
5570
474c8240 5571@smallexample
c906108c 5572p/x $pc
474c8240 5573@end smallexample
c906108c
SS
5574
5575@noindent
5576Note that no space is required before the slash; this is because command
5577names in @value{GDBN} cannot contain a slash.
5578
5579To reprint the last value in the value history with a different format,
5580you can use the @code{print} command with just a format and no
5581expression. For example, @samp{p/x} reprints the last value in hex.
5582
6d2ebf8b 5583@node Memory
c906108c
SS
5584@section Examining memory
5585
5586You can use the command @code{x} (for ``examine'') to examine memory in
5587any of several formats, independently of your program's data types.
5588
5589@cindex examining memory
5590@table @code
41afff9a 5591@kindex x @r{(examine memory)}
c906108c
SS
5592@item x/@var{nfu} @var{addr}
5593@itemx x @var{addr}
5594@itemx x
5595Use the @code{x} command to examine memory.
5596@end table
5597
5598@var{n}, @var{f}, and @var{u} are all optional parameters that specify how
5599much memory to display and how to format it; @var{addr} is an
5600expression giving the address where you want to start displaying memory.
5601If you use defaults for @var{nfu}, you need not type the slash @samp{/}.
5602Several commands set convenient defaults for @var{addr}.
5603
5604@table @r
5605@item @var{n}, the repeat count
5606The repeat count is a decimal integer; the default is 1. It specifies
5607how much memory (counting by units @var{u}) to display.
5608@c This really is **decimal**; unaffected by 'set radix' as of GDB
5609@c 4.1.2.
5610
5611@item @var{f}, the display format
51274035
EZ
5612The display format is one of the formats used by @code{print}
5613(@samp{x}, @samp{d}, @samp{u}, @samp{o}, @samp{t}, @samp{a}, @samp{c},
5614@samp{f}), and in addition @samp{s} (for null-terminated strings) and
5615@samp{i} (for machine instructions). The default is @samp{x}
5616(hexadecimal) initially. The default changes each time you use either
5617@code{x} or @code{print}.
c906108c
SS
5618
5619@item @var{u}, the unit size
5620The unit size is any of
5621
5622@table @code
5623@item b
5624Bytes.
5625@item h
5626Halfwords (two bytes).
5627@item w
5628Words (four bytes). This is the initial default.
5629@item g
5630Giant words (eight bytes).
5631@end table
5632
5633Each time you specify a unit size with @code{x}, that size becomes the
5634default unit the next time you use @code{x}. (For the @samp{s} and
5635@samp{i} formats, the unit size is ignored and is normally not written.)
5636
5637@item @var{addr}, starting display address
5638@var{addr} is the address where you want @value{GDBN} to begin displaying
5639memory. The expression need not have a pointer value (though it may);
5640it is always interpreted as an integer address of a byte of memory.
5641@xref{Expressions, ,Expressions}, for more information on expressions. The default for
5642@var{addr} is usually just after the last address examined---but several
5643other commands also set the default address: @code{info breakpoints} (to
5644the address of the last breakpoint listed), @code{info line} (to the
5645starting address of a line), and @code{print} (if you use it to display
5646a value from memory).
5647@end table
5648
5649For example, @samp{x/3uh 0x54320} is a request to display three halfwords
5650(@code{h}) of memory, formatted as unsigned decimal integers (@samp{u}),
5651starting at address @code{0x54320}. @samp{x/4xw $sp} prints the four
5652words (@samp{w}) of memory above the stack pointer (here, @samp{$sp};
d4f3574e 5653@pxref{Registers, ,Registers}) in hexadecimal (@samp{x}).
c906108c
SS
5654
5655Since the letters indicating unit sizes are all distinct from the
5656letters specifying output formats, you do not have to remember whether
5657unit size or format comes first; either order works. The output
5658specifications @samp{4xw} and @samp{4wx} mean exactly the same thing.
5659(However, the count @var{n} must come first; @samp{wx4} does not work.)
5660
5661Even though the unit size @var{u} is ignored for the formats @samp{s}
5662and @samp{i}, you might still want to use a count @var{n}; for example,
5663@samp{3i} specifies that you want to see three machine instructions,
5664including any operands. The command @code{disassemble} gives an
d4f3574e 5665alternative way of inspecting machine instructions; see @ref{Machine
c906108c
SS
5666Code,,Source and machine code}.
5667
5668All the defaults for the arguments to @code{x} are designed to make it
5669easy to continue scanning memory with minimal specifications each time
5670you use @code{x}. For example, after you have inspected three machine
5671instructions with @samp{x/3i @var{addr}}, you can inspect the next seven
5672with just @samp{x/7}. If you use @key{RET} to repeat the @code{x} command,
5673the repeat count @var{n} is used again; the other arguments default as
5674for successive uses of @code{x}.
5675
5676@cindex @code{$_}, @code{$__}, and value history
5677The addresses and contents printed by the @code{x} command are not saved
5678in the value history because there is often too much of them and they
5679would get in the way. Instead, @value{GDBN} makes these values available for
5680subsequent use in expressions as values of the convenience variables
5681@code{$_} and @code{$__}. After an @code{x} command, the last address
5682examined is available for use in expressions in the convenience variable
5683@code{$_}. The contents of that address, as examined, are available in
5684the convenience variable @code{$__}.
5685
5686If the @code{x} command has a repeat count, the address and contents saved
5687are from the last memory unit printed; this is not the same as the last
5688address printed if several units were printed on the last line of output.
5689
09d4efe1
EZ
5690@cindex remote memory comparison
5691@cindex verify remote memory image
5692When you are debugging a program running on a remote target machine
5693(@pxref{Remote}), you may wish to verify the program's image in the
5694remote machine's memory against the executable file you downloaded to
5695the target. The @code{compare-sections} command is provided for such
5696situations.
5697
5698@table @code
5699@kindex compare-sections
5700@item compare-sections @r{[}@var{section-name}@r{]}
5701Compare the data of a loadable section @var{section-name} in the
5702executable file of the program being debugged with the same section in
5703the remote machine's memory, and report any mismatches. With no
5704arguments, compares all loadable sections. This command's
5705availability depends on the target's support for the @code{"qCRC"}
5706remote request.
5707@end table
5708
6d2ebf8b 5709@node Auto Display
c906108c
SS
5710@section Automatic display
5711@cindex automatic display
5712@cindex display of expressions
5713
5714If you find that you want to print the value of an expression frequently
5715(to see how it changes), you might want to add it to the @dfn{automatic
5716display list} so that @value{GDBN} prints its value each time your program stops.
5717Each expression added to the list is given a number to identify it;
5718to remove an expression from the list, you specify that number.
5719The automatic display looks like this:
5720
474c8240 5721@smallexample
c906108c
SS
57222: foo = 38
57233: bar[5] = (struct hack *) 0x3804
474c8240 5724@end smallexample
c906108c
SS
5725
5726@noindent
5727This display shows item numbers, expressions and their current values. As with
5728displays you request manually using @code{x} or @code{print}, you can
5729specify the output format you prefer; in fact, @code{display} decides
5730whether to use @code{print} or @code{x} depending on how elaborate your
5731format specification is---it uses @code{x} if you specify a unit size,
5732or one of the two formats (@samp{i} and @samp{s}) that are only
5733supported by @code{x}; otherwise it uses @code{print}.
5734
5735@table @code
5736@kindex display
d4f3574e
SS
5737@item display @var{expr}
5738Add the expression @var{expr} to the list of expressions to display
c906108c
SS
5739each time your program stops. @xref{Expressions, ,Expressions}.
5740
5741@code{display} does not repeat if you press @key{RET} again after using it.
5742
d4f3574e 5743@item display/@var{fmt} @var{expr}
c906108c 5744For @var{fmt} specifying only a display format and not a size or
d4f3574e 5745count, add the expression @var{expr} to the auto-display list but
c906108c
SS
5746arrange to display it each time in the specified format @var{fmt}.
5747@xref{Output Formats,,Output formats}.
5748
5749@item display/@var{fmt} @var{addr}
5750For @var{fmt} @samp{i} or @samp{s}, or including a unit-size or a
5751number of units, add the expression @var{addr} as a memory address to
5752be examined each time your program stops. Examining means in effect
5753doing @samp{x/@var{fmt} @var{addr}}. @xref{Memory, ,Examining memory}.
5754@end table
5755
5756For example, @samp{display/i $pc} can be helpful, to see the machine
5757instruction about to be executed each time execution stops (@samp{$pc}
d4f3574e 5758is a common name for the program counter; @pxref{Registers, ,Registers}).
c906108c
SS
5759
5760@table @code
5761@kindex delete display
5762@kindex undisplay
5763@item undisplay @var{dnums}@dots{}
5764@itemx delete display @var{dnums}@dots{}
5765Remove item numbers @var{dnums} from the list of expressions to display.
5766
5767@code{undisplay} does not repeat if you press @key{RET} after using it.
5768(Otherwise you would just get the error @samp{No display number @dots{}}.)
5769
5770@kindex disable display
5771@item disable display @var{dnums}@dots{}
5772Disable the display of item numbers @var{dnums}. A disabled display
5773item is not printed automatically, but is not forgotten. It may be
5774enabled again later.
5775
5776@kindex enable display
5777@item enable display @var{dnums}@dots{}
5778Enable display of item numbers @var{dnums}. It becomes effective once
5779again in auto display of its expression, until you specify otherwise.
5780
5781@item display
5782Display the current values of the expressions on the list, just as is
5783done when your program stops.
5784
5785@kindex info display
5786@item info display
5787Print the list of expressions previously set up to display
5788automatically, each one with its item number, but without showing the
5789values. This includes disabled expressions, which are marked as such.
5790It also includes expressions which would not be displayed right now
5791because they refer to automatic variables not currently available.
5792@end table
5793
15387254 5794@cindex display disabled out of scope
c906108c
SS
5795If a display expression refers to local variables, then it does not make
5796sense outside the lexical context for which it was set up. Such an
5797expression is disabled when execution enters a context where one of its
5798variables is not defined. For example, if you give the command
5799@code{display last_char} while inside a function with an argument
5800@code{last_char}, @value{GDBN} displays this argument while your program
5801continues to stop inside that function. When it stops elsewhere---where
5802there is no variable @code{last_char}---the display is disabled
5803automatically. The next time your program stops where @code{last_char}
5804is meaningful, you can enable the display expression once again.
5805
6d2ebf8b 5806@node Print Settings
c906108c
SS
5807@section Print settings
5808
5809@cindex format options
5810@cindex print settings
5811@value{GDBN} provides the following ways to control how arrays, structures,
5812and symbols are printed.
5813
5814@noindent
5815These settings are useful for debugging programs in any language:
5816
5817@table @code
4644b6e3 5818@kindex set print
c906108c
SS
5819@item set print address
5820@itemx set print address on
4644b6e3 5821@cindex print/don't print memory addresses
c906108c
SS
5822@value{GDBN} prints memory addresses showing the location of stack
5823traces, structure values, pointer values, breakpoints, and so forth,
5824even when it also displays the contents of those addresses. The default
5825is @code{on}. For example, this is what a stack frame display looks like with
5826@code{set print address on}:
5827
5828@smallexample
5829@group
5830(@value{GDBP}) f
5831#0 set_quotes (lq=0x34c78 "<<", rq=0x34c88 ">>")
5832 at input.c:530
5833530 if (lquote != def_lquote)
5834@end group
5835@end smallexample
5836
5837@item set print address off
5838Do not print addresses when displaying their contents. For example,
5839this is the same stack frame displayed with @code{set print address off}:
5840
5841@smallexample
5842@group
5843(@value{GDBP}) set print addr off
5844(@value{GDBP}) f
5845#0 set_quotes (lq="<<", rq=">>") at input.c:530
5846530 if (lquote != def_lquote)
5847@end group
5848@end smallexample
5849
5850You can use @samp{set print address off} to eliminate all machine
5851dependent displays from the @value{GDBN} interface. For example, with
5852@code{print address off}, you should get the same text for backtraces on
5853all machines---whether or not they involve pointer arguments.
5854
4644b6e3 5855@kindex show print
c906108c
SS
5856@item show print address
5857Show whether or not addresses are to be printed.
5858@end table
5859
5860When @value{GDBN} prints a symbolic address, it normally prints the
5861closest earlier symbol plus an offset. If that symbol does not uniquely
5862identify the address (for example, it is a name whose scope is a single
5863source file), you may need to clarify. One way to do this is with
5864@code{info line}, for example @samp{info line *0x4537}. Alternately,
5865you can set @value{GDBN} to print the source file and line number when
5866it prints a symbolic address:
5867
5868@table @code
c906108c 5869@item set print symbol-filename on
9c16f35a
EZ
5870@cindex source file and line of a symbol
5871@cindex symbol, source file and line
c906108c
SS
5872Tell @value{GDBN} to print the source file name and line number of a
5873symbol in the symbolic form of an address.
5874
5875@item set print symbol-filename off
5876Do not print source file name and line number of a symbol. This is the
5877default.
5878
c906108c
SS
5879@item show print symbol-filename
5880Show whether or not @value{GDBN} will print the source file name and
5881line number of a symbol in the symbolic form of an address.
5882@end table
5883
5884Another situation where it is helpful to show symbol filenames and line
5885numbers is when disassembling code; @value{GDBN} shows you the line
5886number and source file that corresponds to each instruction.
5887
5888Also, you may wish to see the symbolic form only if the address being
5889printed is reasonably close to the closest earlier symbol:
5890
5891@table @code
c906108c 5892@item set print max-symbolic-offset @var{max-offset}
4644b6e3 5893@cindex maximum value for offset of closest symbol
c906108c
SS
5894Tell @value{GDBN} to only display the symbolic form of an address if the
5895offset between the closest earlier symbol and the address is less than
5d161b24 5896@var{max-offset}. The default is 0, which tells @value{GDBN}
c906108c
SS
5897to always print the symbolic form of an address if any symbol precedes it.
5898
c906108c
SS
5899@item show print max-symbolic-offset
5900Ask how large the maximum offset is that @value{GDBN} prints in a
5901symbolic address.
5902@end table
5903
5904@cindex wild pointer, interpreting
5905@cindex pointer, finding referent
5906If you have a pointer and you are not sure where it points, try
5907@samp{set print symbol-filename on}. Then you can determine the name
5908and source file location of the variable where it points, using
5909@samp{p/a @var{pointer}}. This interprets the address in symbolic form.
5910For example, here @value{GDBN} shows that a variable @code{ptt} points
5911at another variable @code{t}, defined in @file{hi2.c}:
5912
474c8240 5913@smallexample
c906108c
SS
5914(@value{GDBP}) set print symbol-filename on
5915(@value{GDBP}) p/a ptt
5916$4 = 0xe008 <t in hi2.c>
474c8240 5917@end smallexample
c906108c
SS
5918
5919@quotation
5920@emph{Warning:} For pointers that point to a local variable, @samp{p/a}
5921does not show the symbol name and filename of the referent, even with
5922the appropriate @code{set print} options turned on.
5923@end quotation
5924
5925Other settings control how different kinds of objects are printed:
5926
5927@table @code
c906108c
SS
5928@item set print array
5929@itemx set print array on
4644b6e3 5930@cindex pretty print arrays
c906108c
SS
5931Pretty print arrays. This format is more convenient to read,
5932but uses more space. The default is off.
5933
5934@item set print array off
5935Return to compressed format for arrays.
5936
c906108c
SS
5937@item show print array
5938Show whether compressed or pretty format is selected for displaying
5939arrays.
5940
3c9c013a
JB
5941@cindex print array indexes
5942@item set print array-indexes
5943@itemx set print array-indexes on
5944Print the index of each element when displaying arrays. May be more
5945convenient to locate a given element in the array or quickly find the
5946index of a given element in that printed array. The default is off.
5947
5948@item set print array-indexes off
5949Stop printing element indexes when displaying arrays.
5950
5951@item show print array-indexes
5952Show whether the index of each element is printed when displaying
5953arrays.
5954
c906108c 5955@item set print elements @var{number-of-elements}
4644b6e3 5956@cindex number of array elements to print
9c16f35a 5957@cindex limit on number of printed array elements
c906108c
SS
5958Set a limit on how many elements of an array @value{GDBN} will print.
5959If @value{GDBN} is printing a large array, it stops printing after it has
5960printed the number of elements set by the @code{set print elements} command.
5961This limit also applies to the display of strings.
d4f3574e 5962When @value{GDBN} starts, this limit is set to 200.
c906108c
SS
5963Setting @var{number-of-elements} to zero means that the printing is unlimited.
5964
c906108c
SS
5965@item show print elements
5966Display the number of elements of a large array that @value{GDBN} will print.
5967If the number is 0, then the printing is unlimited.
5968
9c16f35a
EZ
5969@item set print repeats
5970@cindex repeated array elements
5971Set the threshold for suppressing display of repeated array
5972elelments. When the number of consecutive identical elements of an
5973array exceeds the threshold, @value{GDBN} prints the string
5974@code{"<repeats @var{n} times>"}, where @var{n} is the number of
5975identical repetitions, instead of displaying the identical elements
5976themselves. Setting the threshold to zero will cause all elements to
5977be individually printed. The default threshold is 10.
5978
5979@item show print repeats
5980Display the current threshold for printing repeated identical
5981elements.
5982
c906108c 5983@item set print null-stop
4644b6e3 5984@cindex @sc{null} elements in arrays
c906108c 5985Cause @value{GDBN} to stop printing the characters of an array when the first
d4f3574e 5986@sc{null} is encountered. This is useful when large arrays actually
c906108c 5987contain only short strings.
d4f3574e 5988The default is off.
c906108c 5989
9c16f35a
EZ
5990@item show print null-stop
5991Show whether @value{GDBN} stops printing an array on the first
5992@sc{null} character.
5993
c906108c 5994@item set print pretty on
9c16f35a
EZ
5995@cindex print structures in indented form
5996@cindex indentation in structure display
5d161b24 5997Cause @value{GDBN} to print structures in an indented format with one member
c906108c
SS
5998per line, like this:
5999
6000@smallexample
6001@group
6002$1 = @{
6003 next = 0x0,
6004 flags = @{
6005 sweet = 1,
6006 sour = 1
6007 @},
6008 meat = 0x54 "Pork"
6009@}
6010@end group
6011@end smallexample
6012
6013@item set print pretty off
6014Cause @value{GDBN} to print structures in a compact format, like this:
6015
6016@smallexample
6017@group
6018$1 = @{next = 0x0, flags = @{sweet = 1, sour = 1@}, \
6019meat = 0x54 "Pork"@}
6020@end group
6021@end smallexample
6022
6023@noindent
6024This is the default format.
6025
c906108c
SS
6026@item show print pretty
6027Show which format @value{GDBN} is using to print structures.
6028
c906108c 6029@item set print sevenbit-strings on
4644b6e3
EZ
6030@cindex eight-bit characters in strings
6031@cindex octal escapes in strings
c906108c
SS
6032Print using only seven-bit characters; if this option is set,
6033@value{GDBN} displays any eight-bit characters (in strings or
6034character values) using the notation @code{\}@var{nnn}. This setting is
6035best if you are working in English (@sc{ascii}) and you use the
6036high-order bit of characters as a marker or ``meta'' bit.
6037
6038@item set print sevenbit-strings off
6039Print full eight-bit characters. This allows the use of more
6040international character sets, and is the default.
6041
c906108c
SS
6042@item show print sevenbit-strings
6043Show whether or not @value{GDBN} is printing only seven-bit characters.
6044
c906108c 6045@item set print union on
4644b6e3 6046@cindex unions in structures, printing
9c16f35a
EZ
6047Tell @value{GDBN} to print unions which are contained in structures
6048and other unions. This is the default setting.
c906108c
SS
6049
6050@item set print union off
9c16f35a
EZ
6051Tell @value{GDBN} not to print unions which are contained in
6052structures and other unions. @value{GDBN} will print @code{"@{...@}"}
6053instead.
c906108c 6054
c906108c
SS
6055@item show print union
6056Ask @value{GDBN} whether or not it will print unions which are contained in
9c16f35a 6057structures and other unions.
c906108c
SS
6058
6059For example, given the declarations
6060
6061@smallexample
6062typedef enum @{Tree, Bug@} Species;
6063typedef enum @{Big_tree, Acorn, Seedling@} Tree_forms;
5d161b24 6064typedef enum @{Caterpillar, Cocoon, Butterfly@}
c906108c
SS
6065 Bug_forms;
6066
6067struct thing @{
6068 Species it;
6069 union @{
6070 Tree_forms tree;
6071 Bug_forms bug;
6072 @} form;
6073@};
6074
6075struct thing foo = @{Tree, @{Acorn@}@};
6076@end smallexample
6077
6078@noindent
6079with @code{set print union on} in effect @samp{p foo} would print
6080
6081@smallexample
6082$1 = @{it = Tree, form = @{tree = Acorn, bug = Cocoon@}@}
6083@end smallexample
6084
6085@noindent
6086and with @code{set print union off} in effect it would print
6087
6088@smallexample
6089$1 = @{it = Tree, form = @{...@}@}
6090@end smallexample
9c16f35a
EZ
6091
6092@noindent
6093@code{set print union} affects programs written in C-like languages
6094and in Pascal.
c906108c
SS
6095@end table
6096
c906108c
SS
6097@need 1000
6098@noindent
b37052ae 6099These settings are of interest when debugging C@t{++} programs:
c906108c
SS
6100
6101@table @code
4644b6e3 6102@cindex demangling C@t{++} names
c906108c
SS
6103@item set print demangle
6104@itemx set print demangle on
b37052ae 6105Print C@t{++} names in their source form rather than in the encoded
c906108c 6106(``mangled'') form passed to the assembler and linker for type-safe
d4f3574e 6107linkage. The default is on.
c906108c 6108
c906108c 6109@item show print demangle
b37052ae 6110Show whether C@t{++} names are printed in mangled or demangled form.
c906108c 6111
c906108c
SS
6112@item set print asm-demangle
6113@itemx set print asm-demangle on
b37052ae 6114Print C@t{++} names in their source form rather than their mangled form, even
c906108c
SS
6115in assembler code printouts such as instruction disassemblies.
6116The default is off.
6117
c906108c 6118@item show print asm-demangle
b37052ae 6119Show whether C@t{++} names in assembly listings are printed in mangled
c906108c
SS
6120or demangled form.
6121
b37052ae
EZ
6122@cindex C@t{++} symbol decoding style
6123@cindex symbol decoding style, C@t{++}
a8f24a35 6124@kindex set demangle-style
c906108c
SS
6125@item set demangle-style @var{style}
6126Choose among several encoding schemes used by different compilers to
b37052ae 6127represent C@t{++} names. The choices for @var{style} are currently:
c906108c
SS
6128
6129@table @code
6130@item auto
6131Allow @value{GDBN} to choose a decoding style by inspecting your program.
6132
6133@item gnu
b37052ae 6134Decode based on the @sc{gnu} C@t{++} compiler (@code{g++}) encoding algorithm.
c906108c 6135This is the default.
c906108c
SS
6136
6137@item hp
b37052ae 6138Decode based on the HP ANSI C@t{++} (@code{aCC}) encoding algorithm.
c906108c
SS
6139
6140@item lucid
b37052ae 6141Decode based on the Lucid C@t{++} compiler (@code{lcc}) encoding algorithm.
c906108c
SS
6142
6143@item arm
b37052ae 6144Decode using the algorithm in the @cite{C@t{++} Annotated Reference Manual}.
c906108c
SS
6145@strong{Warning:} this setting alone is not sufficient to allow
6146debugging @code{cfront}-generated executables. @value{GDBN} would
6147require further enhancement to permit that.
6148
6149@end table
6150If you omit @var{style}, you will see a list of possible formats.
6151
c906108c 6152@item show demangle-style
b37052ae 6153Display the encoding style currently in use for decoding C@t{++} symbols.
c906108c 6154
c906108c
SS
6155@item set print object
6156@itemx set print object on
4644b6e3 6157@cindex derived type of an object, printing
9c16f35a 6158@cindex display derived types
c906108c
SS
6159When displaying a pointer to an object, identify the @emph{actual}
6160(derived) type of the object rather than the @emph{declared} type, using
6161the virtual function table.
6162
6163@item set print object off
6164Display only the declared type of objects, without reference to the
6165virtual function table. This is the default setting.
6166
c906108c
SS
6167@item show print object
6168Show whether actual, or declared, object types are displayed.
6169
c906108c
SS
6170@item set print static-members
6171@itemx set print static-members on
4644b6e3 6172@cindex static members of C@t{++} objects
b37052ae 6173Print static members when displaying a C@t{++} object. The default is on.
c906108c
SS
6174
6175@item set print static-members off
b37052ae 6176Do not print static members when displaying a C@t{++} object.
c906108c 6177
c906108c 6178@item show print static-members
9c16f35a
EZ
6179Show whether C@t{++} static members are printed or not.
6180
6181@item set print pascal_static-members
6182@itemx set print pascal_static-members on
6183@cindex static members of Pacal objects
6184@cindex Pacal objects, static members display
6185Print static members when displaying a Pascal object. The default is on.
6186
6187@item set print pascal_static-members off
6188Do not print static members when displaying a Pascal object.
6189
6190@item show print pascal_static-members
6191Show whether Pascal static members are printed or not.
c906108c
SS
6192
6193@c These don't work with HP ANSI C++ yet.
c906108c
SS
6194@item set print vtbl
6195@itemx set print vtbl on
4644b6e3 6196@cindex pretty print C@t{++} virtual function tables
9c16f35a
EZ
6197@cindex virtual functions (C@t{++}) display
6198@cindex VTBL display
b37052ae 6199Pretty print C@t{++} virtual function tables. The default is off.
c906108c 6200(The @code{vtbl} commands do not work on programs compiled with the HP
b37052ae 6201ANSI C@t{++} compiler (@code{aCC}).)
c906108c
SS
6202
6203@item set print vtbl off
b37052ae 6204Do not pretty print C@t{++} virtual function tables.
c906108c 6205
c906108c 6206@item show print vtbl
b37052ae 6207Show whether C@t{++} virtual function tables are pretty printed, or not.
c906108c 6208@end table
c906108c 6209
6d2ebf8b 6210@node Value History
c906108c
SS
6211@section Value history
6212
6213@cindex value history
9c16f35a 6214@cindex history of values printed by @value{GDBN}
5d161b24
DB
6215Values printed by the @code{print} command are saved in the @value{GDBN}
6216@dfn{value history}. This allows you to refer to them in other expressions.
6217Values are kept until the symbol table is re-read or discarded
6218(for example with the @code{file} or @code{symbol-file} commands).
6219When the symbol table changes, the value history is discarded,
6220since the values may contain pointers back to the types defined in the
c906108c
SS
6221symbol table.
6222
6223@cindex @code{$}
6224@cindex @code{$$}
6225@cindex history number
6226The values printed are given @dfn{history numbers} by which you can
6227refer to them. These are successive integers starting with one.
6228@code{print} shows you the history number assigned to a value by
6229printing @samp{$@var{num} = } before the value; here @var{num} is the
6230history number.
6231
6232To refer to any previous value, use @samp{$} followed by the value's
6233history number. The way @code{print} labels its output is designed to
6234remind you of this. Just @code{$} refers to the most recent value in
6235the history, and @code{$$} refers to the value before that.
6236@code{$$@var{n}} refers to the @var{n}th value from the end; @code{$$2}
6237is the value just prior to @code{$$}, @code{$$1} is equivalent to
6238@code{$$}, and @code{$$0} is equivalent to @code{$}.
6239
6240For example, suppose you have just printed a pointer to a structure and
6241want to see the contents of the structure. It suffices to type
6242
474c8240 6243@smallexample
c906108c 6244p *$
474c8240 6245@end smallexample
c906108c
SS
6246
6247If you have a chain of structures where the component @code{next} points
6248to the next one, you can print the contents of the next one with this:
6249
474c8240 6250@smallexample
c906108c 6251p *$.next
474c8240 6252@end smallexample
c906108c
SS
6253
6254@noindent
6255You can print successive links in the chain by repeating this
6256command---which you can do by just typing @key{RET}.
6257
6258Note that the history records values, not expressions. If the value of
6259@code{x} is 4 and you type these commands:
6260
474c8240 6261@smallexample
c906108c
SS
6262print x
6263set x=5
474c8240 6264@end smallexample
c906108c
SS
6265
6266@noindent
6267then the value recorded in the value history by the @code{print} command
6268remains 4 even though the value of @code{x} has changed.
6269
6270@table @code
6271@kindex show values
6272@item show values
6273Print the last ten values in the value history, with their item numbers.
6274This is like @samp{p@ $$9} repeated ten times, except that @code{show
6275values} does not change the history.
6276
6277@item show values @var{n}
6278Print ten history values centered on history item number @var{n}.
6279
6280@item show values +
6281Print ten history values just after the values last printed. If no more
6282values are available, @code{show values +} produces no display.
6283@end table
6284
6285Pressing @key{RET} to repeat @code{show values @var{n}} has exactly the
6286same effect as @samp{show values +}.
6287
6d2ebf8b 6288@node Convenience Vars
c906108c
SS
6289@section Convenience variables
6290
6291@cindex convenience variables
9c16f35a 6292@cindex user-defined variables
c906108c
SS
6293@value{GDBN} provides @dfn{convenience variables} that you can use within
6294@value{GDBN} to hold on to a value and refer to it later. These variables
6295exist entirely within @value{GDBN}; they are not part of your program, and
6296setting a convenience variable has no direct effect on further execution
6297of your program. That is why you can use them freely.
6298
6299Convenience variables are prefixed with @samp{$}. Any name preceded by
6300@samp{$} can be used for a convenience variable, unless it is one of
d4f3574e 6301the predefined machine-specific register names (@pxref{Registers, ,Registers}).
c906108c
SS
6302(Value history references, in contrast, are @emph{numbers} preceded
6303by @samp{$}. @xref{Value History, ,Value history}.)
6304
6305You can save a value in a convenience variable with an assignment
6306expression, just as you would set a variable in your program.
6307For example:
6308
474c8240 6309@smallexample
c906108c 6310set $foo = *object_ptr
474c8240 6311@end smallexample
c906108c
SS
6312
6313@noindent
6314would save in @code{$foo} the value contained in the object pointed to by
6315@code{object_ptr}.
6316
6317Using a convenience variable for the first time creates it, but its
6318value is @code{void} until you assign a new value. You can alter the
6319value with another assignment at any time.
6320
6321Convenience variables have no fixed types. You can assign a convenience
6322variable any type of value, including structures and arrays, even if
6323that variable already has a value of a different type. The convenience
6324variable, when used as an expression, has the type of its current value.
6325
6326@table @code
6327@kindex show convenience
9c16f35a 6328@cindex show all user variables
c906108c
SS
6329@item show convenience
6330Print a list of convenience variables used so far, and their values.
d4f3574e 6331Abbreviated @code{show conv}.
53e5f3cf
AS
6332
6333@kindex init-if-undefined
6334@cindex convenience variables, initializing
6335@item init-if-undefined $@var{variable} = @var{expression}
6336Set a convenience variable if it has not already been set. This is useful
6337for user-defined commands that keep some state. It is similar, in concept,
6338to using local static variables with initializers in C (except that
6339convenience variables are global). It can also be used to allow users to
6340override default values used in a command script.
6341
6342If the variable is already defined then the expression is not evaluated so
6343any side-effects do not occur.
c906108c
SS
6344@end table
6345
6346One of the ways to use a convenience variable is as a counter to be
6347incremented or a pointer to be advanced. For example, to print
6348a field from successive elements of an array of structures:
6349
474c8240 6350@smallexample
c906108c
SS
6351set $i = 0
6352print bar[$i++]->contents
474c8240 6353@end smallexample
c906108c 6354
d4f3574e
SS
6355@noindent
6356Repeat that command by typing @key{RET}.
c906108c
SS
6357
6358Some convenience variables are created automatically by @value{GDBN} and given
6359values likely to be useful.
6360
6361@table @code
41afff9a 6362@vindex $_@r{, convenience variable}
c906108c
SS
6363@item $_
6364The variable @code{$_} is automatically set by the @code{x} command to
6365the last address examined (@pxref{Memory, ,Examining memory}). Other
6366commands which provide a default address for @code{x} to examine also
6367set @code{$_} to that address; these commands include @code{info line}
6368and @code{info breakpoint}. The type of @code{$_} is @code{void *}
6369except when set by the @code{x} command, in which case it is a pointer
6370to the type of @code{$__}.
6371
41afff9a 6372@vindex $__@r{, convenience variable}
c906108c
SS
6373@item $__
6374The variable @code{$__} is automatically set by the @code{x} command
6375to the value found in the last address examined. Its type is chosen
6376to match the format in which the data was printed.
6377
6378@item $_exitcode
41afff9a 6379@vindex $_exitcode@r{, convenience variable}
c906108c
SS
6380The variable @code{$_exitcode} is automatically set to the exit code when
6381the program being debugged terminates.
6382@end table
6383
53a5351d
JM
6384On HP-UX systems, if you refer to a function or variable name that
6385begins with a dollar sign, @value{GDBN} searches for a user or system
6386name first, before it searches for a convenience variable.
c906108c 6387
6d2ebf8b 6388@node Registers
c906108c
SS
6389@section Registers
6390
6391@cindex registers
6392You can refer to machine register contents, in expressions, as variables
6393with names starting with @samp{$}. The names of registers are different
6394for each machine; use @code{info registers} to see the names used on
6395your machine.
6396
6397@table @code
6398@kindex info registers
6399@item info registers
6400Print the names and values of all registers except floating-point
c85508ee 6401and vector registers (in the selected stack frame).
c906108c
SS
6402
6403@kindex info all-registers
6404@cindex floating point registers
6405@item info all-registers
6406Print the names and values of all registers, including floating-point
c85508ee 6407and vector registers (in the selected stack frame).
c906108c
SS
6408
6409@item info registers @var{regname} @dots{}
6410Print the @dfn{relativized} value of each specified register @var{regname}.
5d161b24
DB
6411As discussed in detail below, register values are normally relative to
6412the selected stack frame. @var{regname} may be any register name valid on
c906108c
SS
6413the machine you are using, with or without the initial @samp{$}.
6414@end table
6415
e09f16f9
EZ
6416@cindex stack pointer register
6417@cindex program counter register
6418@cindex process status register
6419@cindex frame pointer register
6420@cindex standard registers
c906108c
SS
6421@value{GDBN} has four ``standard'' register names that are available (in
6422expressions) on most machines---whenever they do not conflict with an
6423architecture's canonical mnemonics for registers. The register names
6424@code{$pc} and @code{$sp} are used for the program counter register and
6425the stack pointer. @code{$fp} is used for a register that contains a
6426pointer to the current stack frame, and @code{$ps} is used for a
6427register that contains the processor status. For example,
6428you could print the program counter in hex with
6429
474c8240 6430@smallexample
c906108c 6431p/x $pc
474c8240 6432@end smallexample
c906108c
SS
6433
6434@noindent
6435or print the instruction to be executed next with
6436
474c8240 6437@smallexample
c906108c 6438x/i $pc
474c8240 6439@end smallexample
c906108c
SS
6440
6441@noindent
6442or add four to the stack pointer@footnote{This is a way of removing
6443one word from the stack, on machines where stacks grow downward in
6444memory (most machines, nowadays). This assumes that the innermost
6445stack frame is selected; setting @code{$sp} is not allowed when other
6446stack frames are selected. To pop entire frames off the stack,
6447regardless of machine architecture, use @code{return};
d4f3574e 6448see @ref{Returning, ,Returning from a function}.} with
c906108c 6449
474c8240 6450@smallexample
c906108c 6451set $sp += 4
474c8240 6452@end smallexample
c906108c
SS
6453
6454Whenever possible, these four standard register names are available on
6455your machine even though the machine has different canonical mnemonics,
6456so long as there is no conflict. The @code{info registers} command
6457shows the canonical names. For example, on the SPARC, @code{info
6458registers} displays the processor status register as @code{$psr} but you
d4f3574e
SS
6459can also refer to it as @code{$ps}; and on x86-based machines @code{$ps}
6460is an alias for the @sc{eflags} register.
c906108c
SS
6461
6462@value{GDBN} always considers the contents of an ordinary register as an
6463integer when the register is examined in this way. Some machines have
6464special registers which can hold nothing but floating point; these
6465registers are considered to have floating point values. There is no way
6466to refer to the contents of an ordinary register as floating point value
6467(although you can @emph{print} it as a floating point value with
6468@samp{print/f $@var{regname}}).
6469
6470Some registers have distinct ``raw'' and ``virtual'' data formats. This
6471means that the data format in which the register contents are saved by
6472the operating system is not the same one that your program normally
6473sees. For example, the registers of the 68881 floating point
6474coprocessor are always saved in ``extended'' (raw) format, but all C
6475programs expect to work with ``double'' (virtual) format. In such
5d161b24 6476cases, @value{GDBN} normally works with the virtual format only (the format
c906108c
SS
6477that makes sense for your program), but the @code{info registers} command
6478prints the data in both formats.
6479
36b80e65
EZ
6480@cindex SSE registers (x86)
6481@cindex MMX registers (x86)
6482Some machines have special registers whose contents can be interpreted
6483in several different ways. For example, modern x86-based machines
6484have SSE and MMX registers that can hold several values packed
6485together in several different formats. @value{GDBN} refers to such
6486registers in @code{struct} notation:
6487
6488@smallexample
6489(@value{GDBP}) print $xmm1
6490$1 = @{
6491 v4_float = @{0, 3.43859137e-038, 1.54142831e-044, 1.821688e-044@},
6492 v2_double = @{9.92129282474342e-303, 2.7585945287983262e-313@},
6493 v16_int8 = "\000\000\000\000\3706;\001\v\000\000\000\r\000\000",
6494 v8_int16 = @{0, 0, 14072, 315, 11, 0, 13, 0@},
6495 v4_int32 = @{0, 20657912, 11, 13@},
6496 v2_int64 = @{88725056443645952, 55834574859@},
6497 uint128 = 0x0000000d0000000b013b36f800000000
6498@}
6499@end smallexample
6500
6501@noindent
6502To set values of such registers, you need to tell @value{GDBN} which
6503view of the register you wish to change, as if you were assigning
6504value to a @code{struct} member:
6505
6506@smallexample
6507 (@value{GDBP}) set $xmm1.uint128 = 0x000000000000000000000000FFFFFFFF
6508@end smallexample
6509
c906108c
SS
6510Normally, register values are relative to the selected stack frame
6511(@pxref{Selection, ,Selecting a frame}). This means that you get the
6512value that the register would contain if all stack frames farther in
6513were exited and their saved registers restored. In order to see the
6514true contents of hardware registers, you must select the innermost
6515frame (with @samp{frame 0}).
6516
6517However, @value{GDBN} must deduce where registers are saved, from the machine
6518code generated by your compiler. If some registers are not saved, or if
6519@value{GDBN} is unable to locate the saved registers, the selected stack
6520frame makes no difference.
6521
6d2ebf8b 6522@node Floating Point Hardware
c906108c
SS
6523@section Floating point hardware
6524@cindex floating point
6525
6526Depending on the configuration, @value{GDBN} may be able to give
6527you more information about the status of the floating point hardware.
6528
6529@table @code
6530@kindex info float
6531@item info float
6532Display hardware-dependent information about the floating
6533point unit. The exact contents and layout vary depending on the
6534floating point chip. Currently, @samp{info float} is supported on
6535the ARM and x86 machines.
6536@end table
c906108c 6537
e76f1f2e
AC
6538@node Vector Unit
6539@section Vector Unit
6540@cindex vector unit
6541
6542Depending on the configuration, @value{GDBN} may be able to give you
6543more information about the status of the vector unit.
6544
6545@table @code
6546@kindex info vector
6547@item info vector
6548Display information about the vector unit. The exact contents and
6549layout vary depending on the hardware.
6550@end table
6551
721c2651
EZ
6552@node OS Information
6553@section Operating system auxiliary information
6554@cindex OS information
6555
6556@value{GDBN} provides interfaces to useful OS facilities that can help
6557you debug your program.
6558
6559@cindex @code{ptrace} system call
6560@cindex @code{struct user} contents
6561When @value{GDBN} runs on a @dfn{Posix system} (such as GNU or Unix
6562machines), it interfaces with the inferior via the @code{ptrace}
6563system call. The operating system creates a special sata structure,
6564called @code{struct user}, for this interface. You can use the
6565command @code{info udot} to display the contents of this data
6566structure.
6567
6568@table @code
6569@item info udot
6570@kindex info udot
6571Display the contents of the @code{struct user} maintained by the OS
6572kernel for the program being debugged. @value{GDBN} displays the
6573contents of @code{struct user} as a list of hex numbers, similar to
6574the @code{examine} command.
6575@end table
6576
b383017d
RM
6577@cindex auxiliary vector
6578@cindex vector, auxiliary
b383017d
RM
6579Some operating systems supply an @dfn{auxiliary vector} to programs at
6580startup. This is akin to the arguments and environment that you
6581specify for a program, but contains a system-dependent variety of
6582binary values that tell system libraries important details about the
6583hardware, operating system, and process. Each value's purpose is
6584identified by an integer tag; the meanings are well-known but system-specific.
6585Depending on the configuration and operating system facilities,
9c16f35a
EZ
6586@value{GDBN} may be able to show you this information. For remote
6587targets, this functionality may further depend on the remote stub's
6588support of the @samp{qPart:auxv:read} packet, see @ref{Remote
6589configuration, auxiliary vector}.
b383017d
RM
6590
6591@table @code
6592@kindex info auxv
6593@item info auxv
6594Display the auxiliary vector of the inferior, which can be either a
e4937fc1 6595live process or a core dump file. @value{GDBN} prints each tag value
b383017d
RM
6596numerically, and also shows names and text descriptions for recognized
6597tags. Some values in the vector are numbers, some bit masks, and some
e4937fc1 6598pointers to strings or other data. @value{GDBN} displays each value in the
b383017d
RM
6599most appropriate form for a recognized tag, and in hexadecimal for
6600an unrecognized tag.
6601@end table
6602
721c2651 6603
29e57380 6604@node Memory Region Attributes
b383017d 6605@section Memory region attributes
29e57380
C
6606@cindex memory region attributes
6607
b383017d
RM
6608@dfn{Memory region attributes} allow you to describe special handling
6609required by regions of your target's memory. @value{GDBN} uses attributes
29e57380
C
6610to determine whether to allow certain types of memory accesses; whether to
6611use specific width accesses; and whether to cache target memory.
6612
6613Defined memory regions can be individually enabled and disabled. When a
6614memory region is disabled, @value{GDBN} uses the default attributes when
6615accessing memory in that region. Similarly, if no memory regions have
6616been defined, @value{GDBN} uses the default attributes when accessing
6617all memory.
6618
b383017d 6619When a memory region is defined, it is given a number to identify it;
29e57380
C
6620to enable, disable, or remove a memory region, you specify that number.
6621
6622@table @code
6623@kindex mem
bfac230e 6624@item mem @var{lower} @var{upper} @var{attributes}@dots{}
09d4efe1
EZ
6625Define a memory region bounded by @var{lower} and @var{upper} with
6626attributes @var{attributes}@dots{}, and add it to the list of regions
6627monitored by @value{GDBN}. Note that @var{upper} == 0 is a special
6628case: it is treated as the the target's maximum memory address.
bfac230e 6629(0xffff on 16 bit targets, 0xffffffff on 32 bit targets, etc.)
29e57380
C
6630
6631@kindex delete mem
6632@item delete mem @var{nums}@dots{}
09d4efe1
EZ
6633Remove memory regions @var{nums}@dots{} from the list of regions
6634monitored by @value{GDBN}.
29e57380
C
6635
6636@kindex disable mem
6637@item disable mem @var{nums}@dots{}
09d4efe1 6638Disable monitoring of memory regions @var{nums}@dots{}.
b383017d 6639A disabled memory region is not forgotten.
29e57380
C
6640It may be enabled again later.
6641
6642@kindex enable mem
6643@item enable mem @var{nums}@dots{}
09d4efe1 6644Enable monitoring of memory regions @var{nums}@dots{}.
29e57380
C
6645
6646@kindex info mem
6647@item info mem
6648Print a table of all defined memory regions, with the following columns
09d4efe1 6649for each region:
29e57380
C
6650
6651@table @emph
6652@item Memory Region Number
6653@item Enabled or Disabled.
b383017d 6654Enabled memory regions are marked with @samp{y}.
29e57380
C
6655Disabled memory regions are marked with @samp{n}.
6656
6657@item Lo Address
6658The address defining the inclusive lower bound of the memory region.
6659
6660@item Hi Address
6661The address defining the exclusive upper bound of the memory region.
6662
6663@item Attributes
6664The list of attributes set for this memory region.
6665@end table
6666@end table
6667
6668
6669@subsection Attributes
6670
b383017d 6671@subsubsection Memory Access Mode
29e57380
C
6672The access mode attributes set whether @value{GDBN} may make read or
6673write accesses to a memory region.
6674
6675While these attributes prevent @value{GDBN} from performing invalid
6676memory accesses, they do nothing to prevent the target system, I/O DMA,
359df76b 6677etc.@: from accessing memory.
29e57380
C
6678
6679@table @code
6680@item ro
6681Memory is read only.
6682@item wo
6683Memory is write only.
6684@item rw
6ca652b0 6685Memory is read/write. This is the default.
29e57380
C
6686@end table
6687
6688@subsubsection Memory Access Size
6689The acccess size attributes tells @value{GDBN} to use specific sized
6690accesses in the memory region. Often memory mapped device registers
6691require specific sized accesses. If no access size attribute is
6692specified, @value{GDBN} may use accesses of any size.
6693
6694@table @code
6695@item 8
6696Use 8 bit memory accesses.
6697@item 16
6698Use 16 bit memory accesses.
6699@item 32
6700Use 32 bit memory accesses.
6701@item 64
6702Use 64 bit memory accesses.
6703@end table
6704
6705@c @subsubsection Hardware/Software Breakpoints
6706@c The hardware/software breakpoint attributes set whether @value{GDBN}
6707@c will use hardware or software breakpoints for the internal breakpoints
6708@c used by the step, next, finish, until, etc. commands.
6709@c
6710@c @table @code
6711@c @item hwbreak
b383017d 6712@c Always use hardware breakpoints
29e57380
C
6713@c @item swbreak (default)
6714@c @end table
6715
6716@subsubsection Data Cache
6717The data cache attributes set whether @value{GDBN} will cache target
6718memory. While this generally improves performance by reducing debug
6719protocol overhead, it can lead to incorrect results because @value{GDBN}
6720does not know about volatile variables or memory mapped device
6721registers.
6722
6723@table @code
6724@item cache
b383017d 6725Enable @value{GDBN} to cache target memory.
6ca652b0
EZ
6726@item nocache
6727Disable @value{GDBN} from caching target memory. This is the default.
29e57380
C
6728@end table
6729
6730@c @subsubsection Memory Write Verification
b383017d 6731@c The memory write verification attributes set whether @value{GDBN}
29e57380
C
6732@c will re-reads data after each write to verify the write was successful.
6733@c
6734@c @table @code
6735@c @item verify
6736@c @item noverify (default)
6737@c @end table
6738
16d9dec6
MS
6739@node Dump/Restore Files
6740@section Copy between memory and a file
6741@cindex dump/restore files
6742@cindex append data to a file
6743@cindex dump data to a file
6744@cindex restore data from a file
16d9dec6 6745
df5215a6
JB
6746You can use the commands @code{dump}, @code{append}, and
6747@code{restore} to copy data between target memory and a file. The
6748@code{dump} and @code{append} commands write data to a file, and the
6749@code{restore} command reads data from a file back into the inferior's
6750memory. Files may be in binary, Motorola S-record, Intel hex, or
6751Tektronix Hex format; however, @value{GDBN} can only append to binary
6752files.
6753
6754@table @code
6755
6756@kindex dump
6757@item dump @r{[}@var{format}@r{]} memory @var{filename} @var{start_addr} @var{end_addr}
6758@itemx dump @r{[}@var{format}@r{]} value @var{filename} @var{expr}
6759Dump the contents of memory from @var{start_addr} to @var{end_addr},
6760or the value of @var{expr}, to @var{filename} in the given format.
16d9dec6 6761
df5215a6 6762The @var{format} parameter may be any one of:
16d9dec6 6763@table @code
df5215a6
JB
6764@item binary
6765Raw binary form.
6766@item ihex
6767Intel hex format.
6768@item srec
6769Motorola S-record format.
6770@item tekhex
6771Tektronix Hex format.
6772@end table
6773
6774@value{GDBN} uses the same definitions of these formats as the
6775@sc{gnu} binary utilities, like @samp{objdump} and @samp{objcopy}. If
6776@var{format} is omitted, @value{GDBN} dumps the data in raw binary
6777form.
6778
6779@kindex append
6780@item append @r{[}binary@r{]} memory @var{filename} @var{start_addr} @var{end_addr}
6781@itemx append @r{[}binary@r{]} value @var{filename} @var{expr}
6782Append the contents of memory from @var{start_addr} to @var{end_addr},
09d4efe1 6783or the value of @var{expr}, to the file @var{filename}, in raw binary form.
df5215a6
JB
6784(@value{GDBN} can only append data to files in raw binary form.)
6785
6786@kindex restore
6787@item restore @var{filename} @r{[}binary@r{]} @var{bias} @var{start} @var{end}
6788Restore the contents of file @var{filename} into memory. The
6789@code{restore} command can automatically recognize any known @sc{bfd}
6790file format, except for raw binary. To restore a raw binary file you
6791must specify the optional keyword @code{binary} after the filename.
16d9dec6 6792
b383017d 6793If @var{bias} is non-zero, its value will be added to the addresses
16d9dec6
MS
6794contained in the file. Binary files always start at address zero, so
6795they will be restored at address @var{bias}. Other bfd files have
6796a built-in location; they will be restored at offset @var{bias}
6797from that location.
6798
6799If @var{start} and/or @var{end} are non-zero, then only data between
6800file offset @var{start} and file offset @var{end} will be restored.
b383017d 6801These offsets are relative to the addresses in the file, before
16d9dec6
MS
6802the @var{bias} argument is applied.
6803
6804@end table
6805
384ee23f
EZ
6806@node Core File Generation
6807@section How to Produce a Core File from Your Program
6808@cindex dump core from inferior
6809
6810A @dfn{core file} or @dfn{core dump} is a file that records the memory
6811image of a running process and its process status (register values
6812etc.). Its primary use is post-mortem debugging of a program that
6813crashed while it ran outside a debugger. A program that crashes
6814automatically produces a core file, unless this feature is disabled by
6815the user. @xref{Files}, for information on invoking @value{GDBN} in
6816the post-mortem debugging mode.
6817
6818Occasionally, you may wish to produce a core file of the program you
6819are debugging in order to preserve a snapshot of its state.
6820@value{GDBN} has a special command for that.
6821
6822@table @code
6823@kindex gcore
6824@kindex generate-core-file
6825@item generate-core-file [@var{file}]
6826@itemx gcore [@var{file}]
6827Produce a core dump of the inferior process. The optional argument
6828@var{file} specifies the file name where to put the core dump. If not
6829specified, the file name defaults to @file{core.@var{pid}}, where
6830@var{pid} is the inferior process ID.
6831
6832Note that this command is implemented only for some systems (as of
6833this writing, @sc{gnu}/Linux, FreeBSD, Solaris, Unixware, and S390).
6834@end table
6835
a0eb71c5
KB
6836@node Character Sets
6837@section Character Sets
6838@cindex character sets
6839@cindex charset
6840@cindex translating between character sets
6841@cindex host character set
6842@cindex target character set
6843
6844If the program you are debugging uses a different character set to
6845represent characters and strings than the one @value{GDBN} uses itself,
6846@value{GDBN} can automatically translate between the character sets for
6847you. The character set @value{GDBN} uses we call the @dfn{host
6848character set}; the one the inferior program uses we call the
6849@dfn{target character set}.
6850
6851For example, if you are running @value{GDBN} on a @sc{gnu}/Linux system, which
6852uses the ISO Latin 1 character set, but you are using @value{GDBN}'s
6853remote protocol (@pxref{Remote,Remote Debugging}) to debug a program
6854running on an IBM mainframe, which uses the @sc{ebcdic} character set,
6855then the host character set is Latin-1, and the target character set is
6856@sc{ebcdic}. If you give @value{GDBN} the command @code{set
e33d66ec 6857target-charset EBCDIC-US}, then @value{GDBN} translates between
a0eb71c5
KB
6858@sc{ebcdic} and Latin 1 as you print character or string values, or use
6859character and string literals in expressions.
6860
6861@value{GDBN} has no way to automatically recognize which character set
6862the inferior program uses; you must tell it, using the @code{set
6863target-charset} command, described below.
6864
6865Here are the commands for controlling @value{GDBN}'s character set
6866support:
6867
6868@table @code
6869@item set target-charset @var{charset}
6870@kindex set target-charset
6871Set the current target character set to @var{charset}. We list the
e33d66ec
EZ
6872character set names @value{GDBN} recognizes below, but if you type
6873@code{set target-charset} followed by @key{TAB}@key{TAB}, @value{GDBN} will
6874list the target character sets it supports.
a0eb71c5
KB
6875@end table
6876
6877@table @code
6878@item set host-charset @var{charset}
6879@kindex set host-charset
6880Set the current host character set to @var{charset}.
6881
6882By default, @value{GDBN} uses a host character set appropriate to the
6883system it is running on; you can override that default using the
6884@code{set host-charset} command.
6885
6886@value{GDBN} can only use certain character sets as its host character
6887set. We list the character set names @value{GDBN} recognizes below, and
e33d66ec
EZ
6888indicate which can be host character sets, but if you type
6889@code{set target-charset} followed by @key{TAB}@key{TAB}, @value{GDBN} will
6890list the host character sets it supports.
a0eb71c5
KB
6891
6892@item set charset @var{charset}
6893@kindex set charset
e33d66ec
EZ
6894Set the current host and target character sets to @var{charset}. As
6895above, if you type @code{set charset} followed by @key{TAB}@key{TAB},
6896@value{GDBN} will list the name of the character sets that can be used
6897for both host and target.
6898
a0eb71c5
KB
6899
6900@item show charset
a0eb71c5 6901@kindex show charset
b383017d 6902Show the names of the current host and target charsets.
e33d66ec
EZ
6903
6904@itemx show host-charset
a0eb71c5 6905@kindex show host-charset
b383017d 6906Show the name of the current host charset.
e33d66ec
EZ
6907
6908@itemx show target-charset
a0eb71c5 6909@kindex show target-charset
b383017d 6910Show the name of the current target charset.
a0eb71c5
KB
6911
6912@end table
6913
6914@value{GDBN} currently includes support for the following character
6915sets:
6916
6917@table @code
6918
6919@item ASCII
6920@cindex ASCII character set
6921Seven-bit U.S. @sc{ascii}. @value{GDBN} can use this as its host
6922character set.
6923
6924@item ISO-8859-1
6925@cindex ISO 8859-1 character set
6926@cindex ISO Latin 1 character set
e33d66ec 6927The ISO Latin 1 character set. This extends @sc{ascii} with accented
a0eb71c5
KB
6928characters needed for French, German, and Spanish. @value{GDBN} can use
6929this as its host character set.
6930
6931@item EBCDIC-US
6932@itemx IBM1047
6933@cindex EBCDIC character set
6934@cindex IBM1047 character set
6935Variants of the @sc{ebcdic} character set, used on some of IBM's
6936mainframe operating systems. (@sc{gnu}/Linux on the S/390 uses U.S. @sc{ascii}.)
6937@value{GDBN} cannot use these as its host character set.
6938
6939@end table
6940
6941Note that these are all single-byte character sets. More work inside
6942GDB is needed to support multi-byte or variable-width character
6943encodings, like the UTF-8 and UCS-2 encodings of Unicode.
6944
6945Here is an example of @value{GDBN}'s character set support in action.
6946Assume that the following source code has been placed in the file
6947@file{charset-test.c}:
6948
6949@smallexample
6950#include <stdio.h>
6951
6952char ascii_hello[]
6953 = @{72, 101, 108, 108, 111, 44, 32, 119,
6954 111, 114, 108, 100, 33, 10, 0@};
6955char ibm1047_hello[]
6956 = @{200, 133, 147, 147, 150, 107, 64, 166,
6957 150, 153, 147, 132, 90, 37, 0@};
6958
6959main ()
6960@{
6961 printf ("Hello, world!\n");
6962@}
10998722 6963@end smallexample
a0eb71c5
KB
6964
6965In this program, @code{ascii_hello} and @code{ibm1047_hello} are arrays
6966containing the string @samp{Hello, world!} followed by a newline,
6967encoded in the @sc{ascii} and @sc{ibm1047} character sets.
6968
6969We compile the program, and invoke the debugger on it:
6970
6971@smallexample
6972$ gcc -g charset-test.c -o charset-test
6973$ gdb -nw charset-test
6974GNU gdb 2001-12-19-cvs
6975Copyright 2001 Free Software Foundation, Inc.
6976@dots{}
f7dc1244 6977(@value{GDBP})
10998722 6978@end smallexample
a0eb71c5
KB
6979
6980We can use the @code{show charset} command to see what character sets
6981@value{GDBN} is currently using to interpret and display characters and
6982strings:
6983
6984@smallexample
f7dc1244 6985(@value{GDBP}) show charset
e33d66ec 6986The current host and target character set is `ISO-8859-1'.
f7dc1244 6987(@value{GDBP})
10998722 6988@end smallexample
a0eb71c5
KB
6989
6990For the sake of printing this manual, let's use @sc{ascii} as our
6991initial character set:
6992@smallexample
f7dc1244
EZ
6993(@value{GDBP}) set charset ASCII
6994(@value{GDBP}) show charset
e33d66ec 6995The current host and target character set is `ASCII'.
f7dc1244 6996(@value{GDBP})
10998722 6997@end smallexample
a0eb71c5
KB
6998
6999Let's assume that @sc{ascii} is indeed the correct character set for our
7000host system --- in other words, let's assume that if @value{GDBN} prints
7001characters using the @sc{ascii} character set, our terminal will display
7002them properly. Since our current target character set is also
7003@sc{ascii}, the contents of @code{ascii_hello} print legibly:
7004
7005@smallexample
f7dc1244 7006(@value{GDBP}) print ascii_hello
a0eb71c5 7007$1 = 0x401698 "Hello, world!\n"
f7dc1244 7008(@value{GDBP}) print ascii_hello[0]
a0eb71c5 7009$2 = 72 'H'
f7dc1244 7010(@value{GDBP})
10998722 7011@end smallexample
a0eb71c5
KB
7012
7013@value{GDBN} uses the target character set for character and string
7014literals you use in expressions:
7015
7016@smallexample
f7dc1244 7017(@value{GDBP}) print '+'
a0eb71c5 7018$3 = 43 '+'
f7dc1244 7019(@value{GDBP})
10998722 7020@end smallexample
a0eb71c5
KB
7021
7022The @sc{ascii} character set uses the number 43 to encode the @samp{+}
7023character.
7024
7025@value{GDBN} relies on the user to tell it which character set the
7026target program uses. If we print @code{ibm1047_hello} while our target
7027character set is still @sc{ascii}, we get jibberish:
7028
7029@smallexample
f7dc1244 7030(@value{GDBP}) print ibm1047_hello
a0eb71c5 7031$4 = 0x4016a8 "\310\205\223\223\226k@@\246\226\231\223\204Z%"
f7dc1244 7032(@value{GDBP}) print ibm1047_hello[0]
a0eb71c5 7033$5 = 200 '\310'
f7dc1244 7034(@value{GDBP})
10998722 7035@end smallexample
a0eb71c5 7036
e33d66ec 7037If we invoke the @code{set target-charset} followed by @key{TAB}@key{TAB},
a0eb71c5
KB
7038@value{GDBN} tells us the character sets it supports:
7039
7040@smallexample
f7dc1244 7041(@value{GDBP}) set target-charset
b383017d 7042ASCII EBCDIC-US IBM1047 ISO-8859-1
f7dc1244 7043(@value{GDBP}) set target-charset
10998722 7044@end smallexample
a0eb71c5
KB
7045
7046We can select @sc{ibm1047} as our target character set, and examine the
7047program's strings again. Now the @sc{ascii} string is wrong, but
7048@value{GDBN} translates the contents of @code{ibm1047_hello} from the
7049target character set, @sc{ibm1047}, to the host character set,
7050@sc{ascii}, and they display correctly:
7051
7052@smallexample
f7dc1244
EZ
7053(@value{GDBP}) set target-charset IBM1047
7054(@value{GDBP}) show charset
e33d66ec
EZ
7055The current host character set is `ASCII'.
7056The current target character set is `IBM1047'.
f7dc1244 7057(@value{GDBP}) print ascii_hello
a0eb71c5 7058$6 = 0x401698 "\110\145%%?\054\040\167?\162%\144\041\012"
f7dc1244 7059(@value{GDBP}) print ascii_hello[0]
a0eb71c5 7060$7 = 72 '\110'
f7dc1244 7061(@value{GDBP}) print ibm1047_hello
a0eb71c5 7062$8 = 0x4016a8 "Hello, world!\n"
f7dc1244 7063(@value{GDBP}) print ibm1047_hello[0]
a0eb71c5 7064$9 = 200 'H'
f7dc1244 7065(@value{GDBP})
10998722 7066@end smallexample
a0eb71c5
KB
7067
7068As above, @value{GDBN} uses the target character set for character and
7069string literals you use in expressions:
7070
7071@smallexample
f7dc1244 7072(@value{GDBP}) print '+'
a0eb71c5 7073$10 = 78 '+'
f7dc1244 7074(@value{GDBP})
10998722 7075@end smallexample
a0eb71c5 7076
e33d66ec 7077The @sc{ibm1047} character set uses the number 78 to encode the @samp{+}
a0eb71c5
KB
7078character.
7079
09d4efe1
EZ
7080@node Caching Remote Data
7081@section Caching Data of Remote Targets
7082@cindex caching data of remote targets
7083
7084@value{GDBN} can cache data exchanged between the debugger and a
7085remote target (@pxref{Remote}). Such caching generally improves
7086performance, because it reduces the overhead of the remote protocol by
7087bundling memory reads and writes into large chunks. Unfortunately,
7088@value{GDBN} does not currently know anything about volatile
7089registers, and thus data caching will produce incorrect results when
7090volatile registers are in use.
7091
7092@table @code
7093@kindex set remotecache
7094@item set remotecache on
7095@itemx set remotecache off
7096Set caching state for remote targets. When @code{ON}, use data
7097caching. By default, this option is @code{OFF}.
7098
7099@kindex show remotecache
7100@item show remotecache
7101Show the current state of data caching for remote targets.
7102
7103@kindex info dcache
7104@item info dcache
7105Print the information about the data cache performance. The
7106information displayed includes: the dcache width and depth; and for
7107each cache line, how many times it was referenced, and its data and
7108state (dirty, bad, ok, etc.). This command is useful for debugging
7109the data cache operation.
7110@end table
7111
a0eb71c5 7112
e2e0bcd1
JB
7113@node Macros
7114@chapter C Preprocessor Macros
7115
49efadf5 7116Some languages, such as C and C@t{++}, provide a way to define and invoke
e2e0bcd1
JB
7117``preprocessor macros'' which expand into strings of tokens.
7118@value{GDBN} can evaluate expressions containing macro invocations, show
7119the result of macro expansion, and show a macro's definition, including
7120where it was defined.
7121
7122You may need to compile your program specially to provide @value{GDBN}
7123with information about preprocessor macros. Most compilers do not
7124include macros in their debugging information, even when you compile
7125with the @option{-g} flag. @xref{Compilation}.
7126
7127A program may define a macro at one point, remove that definition later,
7128and then provide a different definition after that. Thus, at different
7129points in the program, a macro may have different definitions, or have
7130no definition at all. If there is a current stack frame, @value{GDBN}
7131uses the macros in scope at that frame's source code line. Otherwise,
7132@value{GDBN} uses the macros in scope at the current listing location;
7133see @ref{List}.
7134
7135At the moment, @value{GDBN} does not support the @code{##}
7136token-splicing operator, the @code{#} stringification operator, or
7137variable-arity macros.
7138
7139Whenever @value{GDBN} evaluates an expression, it always expands any
7140macro invocations present in the expression. @value{GDBN} also provides
7141the following commands for working with macros explicitly.
7142
7143@table @code
7144
7145@kindex macro expand
7146@cindex macro expansion, showing the results of preprocessor
7147@cindex preprocessor macro expansion, showing the results of
7148@cindex expanding preprocessor macros
7149@item macro expand @var{expression}
7150@itemx macro exp @var{expression}
7151Show the results of expanding all preprocessor macro invocations in
7152@var{expression}. Since @value{GDBN} simply expands macros, but does
7153not parse the result, @var{expression} need not be a valid expression;
7154it can be any string of tokens.
7155
09d4efe1 7156@kindex macro exp1
e2e0bcd1
JB
7157@item macro expand-once @var{expression}
7158@itemx macro exp1 @var{expression}
4644b6e3 7159@cindex expand macro once
e2e0bcd1
JB
7160@i{(This command is not yet implemented.)} Show the results of
7161expanding those preprocessor macro invocations that appear explicitly in
7162@var{expression}. Macro invocations appearing in that expansion are
7163left unchanged. This command allows you to see the effect of a
7164particular macro more clearly, without being confused by further
7165expansions. Since @value{GDBN} simply expands macros, but does not
7166parse the result, @var{expression} need not be a valid expression; it
7167can be any string of tokens.
7168
475b0867 7169@kindex info macro
e2e0bcd1
JB
7170@cindex macro definition, showing
7171@cindex definition, showing a macro's
475b0867 7172@item info macro @var{macro}
e2e0bcd1
JB
7173Show the definition of the macro named @var{macro}, and describe the
7174source location where that definition was established.
7175
7176@kindex macro define
7177@cindex user-defined macros
7178@cindex defining macros interactively
7179@cindex macros, user-defined
7180@item macro define @var{macro} @var{replacement-list}
7181@itemx macro define @var{macro}(@var{arglist}) @var{replacement-list}
7182@i{(This command is not yet implemented.)} Introduce a definition for a
7183preprocessor macro named @var{macro}, invocations of which are replaced
7184by the tokens given in @var{replacement-list}. The first form of this
7185command defines an ``object-like'' macro, which takes no arguments; the
7186second form defines a ``function-like'' macro, which takes the arguments
7187given in @var{arglist}.
7188
7189A definition introduced by this command is in scope in every expression
7190evaluated in @value{GDBN}, until it is removed with the @command{macro
7191undef} command, described below. The definition overrides all
7192definitions for @var{macro} present in the program being debugged, as
7193well as any previous user-supplied definition.
7194
7195@kindex macro undef
7196@item macro undef @var{macro}
7197@i{(This command is not yet implemented.)} Remove any user-supplied
7198definition for the macro named @var{macro}. This command only affects
7199definitions provided with the @command{macro define} command, described
7200above; it cannot remove definitions present in the program being
7201debugged.
7202
09d4efe1
EZ
7203@kindex macro list
7204@item macro list
7205@i{(This command is not yet implemented.)} List all the macros
7206defined using the @code{macro define} command.
e2e0bcd1
JB
7207@end table
7208
7209@cindex macros, example of debugging with
7210Here is a transcript showing the above commands in action. First, we
7211show our source files:
7212
7213@smallexample
7214$ cat sample.c
7215#include <stdio.h>
7216#include "sample.h"
7217
7218#define M 42
7219#define ADD(x) (M + x)
7220
7221main ()
7222@{
7223#define N 28
7224 printf ("Hello, world!\n");
7225#undef N
7226 printf ("We're so creative.\n");
7227#define N 1729
7228 printf ("Goodbye, world!\n");
7229@}
7230$ cat sample.h
7231#define Q <
7232$
7233@end smallexample
7234
7235Now, we compile the program using the @sc{gnu} C compiler, @value{NGCC}.
7236We pass the @option{-gdwarf-2} and @option{-g3} flags to ensure the
7237compiler includes information about preprocessor macros in the debugging
7238information.
7239
7240@smallexample
7241$ gcc -gdwarf-2 -g3 sample.c -o sample
7242$
7243@end smallexample
7244
7245Now, we start @value{GDBN} on our sample program:
7246
7247@smallexample
7248$ gdb -nw sample
7249GNU gdb 2002-05-06-cvs
7250Copyright 2002 Free Software Foundation, Inc.
7251GDB is free software, @dots{}
f7dc1244 7252(@value{GDBP})
e2e0bcd1
JB
7253@end smallexample
7254
7255We can expand macros and examine their definitions, even when the
7256program is not running. @value{GDBN} uses the current listing position
7257to decide which macro definitions are in scope:
7258
7259@smallexample
f7dc1244 7260(@value{GDBP}) list main
e2e0bcd1
JB
72613
72624 #define M 42
72635 #define ADD(x) (M + x)
72646
72657 main ()
72668 @{
72679 #define N 28
726810 printf ("Hello, world!\n");
726911 #undef N
727012 printf ("We're so creative.\n");
f7dc1244 7271(@value{GDBP}) info macro ADD
e2e0bcd1
JB
7272Defined at /home/jimb/gdb/macros/play/sample.c:5
7273#define ADD(x) (M + x)
f7dc1244 7274(@value{GDBP}) info macro Q
e2e0bcd1
JB
7275Defined at /home/jimb/gdb/macros/play/sample.h:1
7276 included at /home/jimb/gdb/macros/play/sample.c:2
7277#define Q <
f7dc1244 7278(@value{GDBP}) macro expand ADD(1)
e2e0bcd1 7279expands to: (42 + 1)
f7dc1244 7280(@value{GDBP}) macro expand-once ADD(1)
e2e0bcd1 7281expands to: once (M + 1)
f7dc1244 7282(@value{GDBP})
e2e0bcd1
JB
7283@end smallexample
7284
7285In the example above, note that @command{macro expand-once} expands only
7286the macro invocation explicit in the original text --- the invocation of
7287@code{ADD} --- but does not expand the invocation of the macro @code{M},
7288which was introduced by @code{ADD}.
7289
7290Once the program is running, GDB uses the macro definitions in force at
7291the source line of the current stack frame:
7292
7293@smallexample
f7dc1244 7294(@value{GDBP}) break main
e2e0bcd1 7295Breakpoint 1 at 0x8048370: file sample.c, line 10.
f7dc1244 7296(@value{GDBP}) run
b383017d 7297Starting program: /home/jimb/gdb/macros/play/sample
e2e0bcd1
JB
7298
7299Breakpoint 1, main () at sample.c:10
730010 printf ("Hello, world!\n");
f7dc1244 7301(@value{GDBP})
e2e0bcd1
JB
7302@end smallexample
7303
7304At line 10, the definition of the macro @code{N} at line 9 is in force:
7305
7306@smallexample
f7dc1244 7307(@value{GDBP}) info macro N
e2e0bcd1
JB
7308Defined at /home/jimb/gdb/macros/play/sample.c:9
7309#define N 28
f7dc1244 7310(@value{GDBP}) macro expand N Q M
e2e0bcd1 7311expands to: 28 < 42
f7dc1244 7312(@value{GDBP}) print N Q M
e2e0bcd1 7313$1 = 1
f7dc1244 7314(@value{GDBP})
e2e0bcd1
JB
7315@end smallexample
7316
7317As we step over directives that remove @code{N}'s definition, and then
7318give it a new definition, @value{GDBN} finds the definition (or lack
7319thereof) in force at each point:
7320
7321@smallexample
f7dc1244 7322(@value{GDBP}) next
e2e0bcd1
JB
7323Hello, world!
732412 printf ("We're so creative.\n");
f7dc1244 7325(@value{GDBP}) info macro N
e2e0bcd1
JB
7326The symbol `N' has no definition as a C/C++ preprocessor macro
7327at /home/jimb/gdb/macros/play/sample.c:12
f7dc1244 7328(@value{GDBP}) next
e2e0bcd1
JB
7329We're so creative.
733014 printf ("Goodbye, world!\n");
f7dc1244 7331(@value{GDBP}) info macro N
e2e0bcd1
JB
7332Defined at /home/jimb/gdb/macros/play/sample.c:13
7333#define N 1729
f7dc1244 7334(@value{GDBP}) macro expand N Q M
e2e0bcd1 7335expands to: 1729 < 42
f7dc1244 7336(@value{GDBP}) print N Q M
e2e0bcd1 7337$2 = 0
f7dc1244 7338(@value{GDBP})
e2e0bcd1
JB
7339@end smallexample
7340
7341
b37052ae
EZ
7342@node Tracepoints
7343@chapter Tracepoints
7344@c This chapter is based on the documentation written by Michael
7345@c Snyder, David Taylor, Jim Blandy, and Elena Zannoni.
7346
7347@cindex tracepoints
7348In some applications, it is not feasible for the debugger to interrupt
7349the program's execution long enough for the developer to learn
7350anything helpful about its behavior. If the program's correctness
7351depends on its real-time behavior, delays introduced by a debugger
7352might cause the program to change its behavior drastically, or perhaps
7353fail, even when the code itself is correct. It is useful to be able
7354to observe the program's behavior without interrupting it.
7355
7356Using @value{GDBN}'s @code{trace} and @code{collect} commands, you can
7357specify locations in the program, called @dfn{tracepoints}, and
7358arbitrary expressions to evaluate when those tracepoints are reached.
7359Later, using the @code{tfind} command, you can examine the values
7360those expressions had when the program hit the tracepoints. The
7361expressions may also denote objects in memory---structures or arrays,
7362for example---whose values @value{GDBN} should record; while visiting
7363a particular tracepoint, you may inspect those objects as if they were
7364in memory at that moment. However, because @value{GDBN} records these
7365values without interacting with you, it can do so quickly and
7366unobtrusively, hopefully not disturbing the program's behavior.
7367
7368The tracepoint facility is currently available only for remote
9d29849a
JB
7369targets. @xref{Targets}. In addition, your remote target must know
7370how to collect trace data. This functionality is implemented in the
7371remote stub; however, none of the stubs distributed with @value{GDBN}
7372support tracepoints as of this writing. The format of the remote
7373packets used to implement tracepoints are described in @ref{Tracepoint
7374Packets}.
b37052ae
EZ
7375
7376This chapter describes the tracepoint commands and features.
7377
7378@menu
b383017d
RM
7379* Set Tracepoints::
7380* Analyze Collected Data::
7381* Tracepoint Variables::
b37052ae
EZ
7382@end menu
7383
7384@node Set Tracepoints
7385@section Commands to Set Tracepoints
7386
7387Before running such a @dfn{trace experiment}, an arbitrary number of
7388tracepoints can be set. Like a breakpoint (@pxref{Set Breaks}), a
7389tracepoint has a number assigned to it by @value{GDBN}. Like with
7390breakpoints, tracepoint numbers are successive integers starting from
7391one. Many of the commands associated with tracepoints take the
7392tracepoint number as their argument, to identify which tracepoint to
7393work on.
7394
7395For each tracepoint, you can specify, in advance, some arbitrary set
7396of data that you want the target to collect in the trace buffer when
7397it hits that tracepoint. The collected data can include registers,
7398local variables, or global data. Later, you can use @value{GDBN}
7399commands to examine the values these data had at the time the
7400tracepoint was hit.
7401
7402This section describes commands to set tracepoints and associated
7403conditions and actions.
7404
7405@menu
b383017d
RM
7406* Create and Delete Tracepoints::
7407* Enable and Disable Tracepoints::
7408* Tracepoint Passcounts::
7409* Tracepoint Actions::
7410* Listing Tracepoints::
7411* Starting and Stopping Trace Experiment::
b37052ae
EZ
7412@end menu
7413
7414@node Create and Delete Tracepoints
7415@subsection Create and Delete Tracepoints
7416
7417@table @code
7418@cindex set tracepoint
7419@kindex trace
7420@item trace
7421The @code{trace} command is very similar to the @code{break} command.
7422Its argument can be a source line, a function name, or an address in
7423the target program. @xref{Set Breaks}. The @code{trace} command
7424defines a tracepoint, which is a point in the target program where the
7425debugger will briefly stop, collect some data, and then allow the
7426program to continue. Setting a tracepoint or changing its commands
7427doesn't take effect until the next @code{tstart} command; thus, you
7428cannot change the tracepoint attributes once a trace experiment is
7429running.
7430
7431Here are some examples of using the @code{trace} command:
7432
7433@smallexample
7434(@value{GDBP}) @b{trace foo.c:121} // a source file and line number
7435
7436(@value{GDBP}) @b{trace +2} // 2 lines forward
7437
7438(@value{GDBP}) @b{trace my_function} // first source line of function
7439
7440(@value{GDBP}) @b{trace *my_function} // EXACT start address of function
7441
7442(@value{GDBP}) @b{trace *0x2117c4} // an address
7443@end smallexample
7444
7445@noindent
7446You can abbreviate @code{trace} as @code{tr}.
7447
7448@vindex $tpnum
7449@cindex last tracepoint number
7450@cindex recent tracepoint number
7451@cindex tracepoint number
7452The convenience variable @code{$tpnum} records the tracepoint number
7453of the most recently set tracepoint.
7454
7455@kindex delete tracepoint
7456@cindex tracepoint deletion
7457@item delete tracepoint @r{[}@var{num}@r{]}
7458Permanently delete one or more tracepoints. With no argument, the
7459default is to delete all tracepoints.
7460
7461Examples:
7462
7463@smallexample
7464(@value{GDBP}) @b{delete trace 1 2 3} // remove three tracepoints
7465
7466(@value{GDBP}) @b{delete trace} // remove all tracepoints
7467@end smallexample
7468
7469@noindent
7470You can abbreviate this command as @code{del tr}.
7471@end table
7472
7473@node Enable and Disable Tracepoints
7474@subsection Enable and Disable Tracepoints
7475
7476@table @code
7477@kindex disable tracepoint
7478@item disable tracepoint @r{[}@var{num}@r{]}
7479Disable tracepoint @var{num}, or all tracepoints if no argument
7480@var{num} is given. A disabled tracepoint will have no effect during
7481the next trace experiment, but it is not forgotten. You can re-enable
7482a disabled tracepoint using the @code{enable tracepoint} command.
7483
7484@kindex enable tracepoint
7485@item enable tracepoint @r{[}@var{num}@r{]}
7486Enable tracepoint @var{num}, or all tracepoints. The enabled
7487tracepoints will become effective the next time a trace experiment is
7488run.
7489@end table
7490
7491@node Tracepoint Passcounts
7492@subsection Tracepoint Passcounts
7493
7494@table @code
7495@kindex passcount
7496@cindex tracepoint pass count
7497@item passcount @r{[}@var{n} @r{[}@var{num}@r{]]}
7498Set the @dfn{passcount} of a tracepoint. The passcount is a way to
7499automatically stop a trace experiment. If a tracepoint's passcount is
7500@var{n}, then the trace experiment will be automatically stopped on
7501the @var{n}'th time that tracepoint is hit. If the tracepoint number
7502@var{num} is not specified, the @code{passcount} command sets the
7503passcount of the most recently defined tracepoint. If no passcount is
7504given, the trace experiment will run until stopped explicitly by the
7505user.
7506
7507Examples:
7508
7509@smallexample
b383017d 7510(@value{GDBP}) @b{passcount 5 2} // Stop on the 5th execution of
6826cf00 7511@exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// tracepoint 2}
b37052ae
EZ
7512
7513(@value{GDBP}) @b{passcount 12} // Stop on the 12th execution of the
6826cf00 7514@exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// most recently defined tracepoint.}
b37052ae
EZ
7515(@value{GDBP}) @b{trace foo}
7516(@value{GDBP}) @b{pass 3}
7517(@value{GDBP}) @b{trace bar}
7518(@value{GDBP}) @b{pass 2}
7519(@value{GDBP}) @b{trace baz}
7520(@value{GDBP}) @b{pass 1} // Stop tracing when foo has been
6826cf00
EZ
7521@exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// executed 3 times OR when bar has}
7522@exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// been executed 2 times}
7523@exdent @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @code{// OR when baz has been executed 1 time.}
b37052ae
EZ
7524@end smallexample
7525@end table
7526
7527@node Tracepoint Actions
7528@subsection Tracepoint Action Lists
7529
7530@table @code
7531@kindex actions
7532@cindex tracepoint actions
7533@item actions @r{[}@var{num}@r{]}
7534This command will prompt for a list of actions to be taken when the
7535tracepoint is hit. If the tracepoint number @var{num} is not
7536specified, this command sets the actions for the one that was most
7537recently defined (so that you can define a tracepoint and then say
7538@code{actions} without bothering about its number). You specify the
7539actions themselves on the following lines, one action at a time, and
7540terminate the actions list with a line containing just @code{end}. So
7541far, the only defined actions are @code{collect} and
7542@code{while-stepping}.
7543
7544@cindex remove actions from a tracepoint
7545To remove all actions from a tracepoint, type @samp{actions @var{num}}
7546and follow it immediately with @samp{end}.
7547
7548@smallexample
7549(@value{GDBP}) @b{collect @var{data}} // collect some data
7550
6826cf00 7551(@value{GDBP}) @b{while-stepping 5} // single-step 5 times, collect data
b37052ae 7552
6826cf00 7553(@value{GDBP}) @b{end} // signals the end of actions.
b37052ae
EZ
7554@end smallexample
7555
7556In the following example, the action list begins with @code{collect}
7557commands indicating the things to be collected when the tracepoint is
7558hit. Then, in order to single-step and collect additional data
7559following the tracepoint, a @code{while-stepping} command is used,
7560followed by the list of things to be collected while stepping. The
7561@code{while-stepping} command is terminated by its own separate
7562@code{end} command. Lastly, the action list is terminated by an
7563@code{end} command.
7564
7565@smallexample
7566(@value{GDBP}) @b{trace foo}
7567(@value{GDBP}) @b{actions}
7568Enter actions for tracepoint 1, one per line:
7569> collect bar,baz
7570> collect $regs
7571> while-stepping 12
7572 > collect $fp, $sp
7573 > end
7574end
7575@end smallexample
7576
7577@kindex collect @r{(tracepoints)}
7578@item collect @var{expr1}, @var{expr2}, @dots{}
7579Collect values of the given expressions when the tracepoint is hit.
7580This command accepts a comma-separated list of any valid expressions.
7581In addition to global, static, or local variables, the following
7582special arguments are supported:
7583
7584@table @code
7585@item $regs
7586collect all registers
7587
7588@item $args
7589collect all function arguments
7590
7591@item $locals
7592collect all local variables.
7593@end table
7594
7595You can give several consecutive @code{collect} commands, each one
7596with a single argument, or one @code{collect} command with several
7597arguments separated by commas: the effect is the same.
7598
f5c37c66
EZ
7599The command @code{info scope} (@pxref{Symbols, info scope}) is
7600particularly useful for figuring out what data to collect.
7601
b37052ae
EZ
7602@kindex while-stepping @r{(tracepoints)}
7603@item while-stepping @var{n}
7604Perform @var{n} single-step traces after the tracepoint, collecting
7605new data at each step. The @code{while-stepping} command is
7606followed by the list of what to collect while stepping (followed by
7607its own @code{end} command):
7608
7609@smallexample
7610> while-stepping 12
7611 > collect $regs, myglobal
7612 > end
7613>
7614@end smallexample
7615
7616@noindent
7617You may abbreviate @code{while-stepping} as @code{ws} or
7618@code{stepping}.
7619@end table
7620
7621@node Listing Tracepoints
7622@subsection Listing Tracepoints
7623
7624@table @code
7625@kindex info tracepoints
09d4efe1 7626@kindex info tp
b37052ae
EZ
7627@cindex information about tracepoints
7628@item info tracepoints @r{[}@var{num}@r{]}
8a037dd7 7629Display information about the tracepoint @var{num}. If you don't specify
798c8bc6 7630a tracepoint number, displays information about all the tracepoints
b37052ae
EZ
7631defined so far. For each tracepoint, the following information is
7632shown:
7633
7634@itemize @bullet
7635@item
7636its number
7637@item
7638whether it is enabled or disabled
7639@item
7640its address
7641@item
7642its passcount as given by the @code{passcount @var{n}} command
7643@item
7644its step count as given by the @code{while-stepping @var{n}} command
7645@item
7646where in the source files is the tracepoint set
7647@item
7648its action list as given by the @code{actions} command
7649@end itemize
7650
7651@smallexample
7652(@value{GDBP}) @b{info trace}
7653Num Enb Address PassC StepC What
76541 y 0x002117c4 0 0 <gdb_asm>
6826cf00
EZ
76552 y 0x0020dc64 0 0 in g_test at g_test.c:1375
76563 y 0x0020b1f4 0 0 in get_data at ../foo.c:41
b37052ae
EZ
7657(@value{GDBP})
7658@end smallexample
7659
7660@noindent
7661This command can be abbreviated @code{info tp}.
7662@end table
7663
7664@node Starting and Stopping Trace Experiment
7665@subsection Starting and Stopping Trace Experiment
7666
7667@table @code
7668@kindex tstart
7669@cindex start a new trace experiment
7670@cindex collected data discarded
7671@item tstart
7672This command takes no arguments. It starts the trace experiment, and
7673begins collecting data. This has the side effect of discarding all
7674the data collected in the trace buffer during the previous trace
7675experiment.
7676
7677@kindex tstop
7678@cindex stop a running trace experiment
7679@item tstop
7680This command takes no arguments. It ends the trace experiment, and
7681stops collecting data.
7682
68c71a2e 7683@strong{Note}: a trace experiment and data collection may stop
b37052ae
EZ
7684automatically if any tracepoint's passcount is reached
7685(@pxref{Tracepoint Passcounts}), or if the trace buffer becomes full.
7686
7687@kindex tstatus
7688@cindex status of trace data collection
7689@cindex trace experiment, status of
7690@item tstatus
7691This command displays the status of the current trace data
7692collection.
7693@end table
7694
7695Here is an example of the commands we described so far:
7696
7697@smallexample
7698(@value{GDBP}) @b{trace gdb_c_test}
7699(@value{GDBP}) @b{actions}
7700Enter actions for tracepoint #1, one per line.
7701> collect $regs,$locals,$args
7702> while-stepping 11
7703 > collect $regs
7704 > end
7705> end
7706(@value{GDBP}) @b{tstart}
7707 [time passes @dots{}]
7708(@value{GDBP}) @b{tstop}
7709@end smallexample
7710
7711
7712@node Analyze Collected Data
7713@section Using the collected data
7714
7715After the tracepoint experiment ends, you use @value{GDBN} commands
7716for examining the trace data. The basic idea is that each tracepoint
7717collects a trace @dfn{snapshot} every time it is hit and another
7718snapshot every time it single-steps. All these snapshots are
7719consecutively numbered from zero and go into a buffer, and you can
7720examine them later. The way you examine them is to @dfn{focus} on a
7721specific trace snapshot. When the remote stub is focused on a trace
7722snapshot, it will respond to all @value{GDBN} requests for memory and
7723registers by reading from the buffer which belongs to that snapshot,
7724rather than from @emph{real} memory or registers of the program being
7725debugged. This means that @strong{all} @value{GDBN} commands
7726(@code{print}, @code{info registers}, @code{backtrace}, etc.) will
7727behave as if we were currently debugging the program state as it was
7728when the tracepoint occurred. Any requests for data that are not in
7729the buffer will fail.
7730
7731@menu
7732* tfind:: How to select a trace snapshot
7733* tdump:: How to display all data for a snapshot
7734* save-tracepoints:: How to save tracepoints for a future run
7735@end menu
7736
7737@node tfind
7738@subsection @code{tfind @var{n}}
7739
7740@kindex tfind
7741@cindex select trace snapshot
7742@cindex find trace snapshot
7743The basic command for selecting a trace snapshot from the buffer is
7744@code{tfind @var{n}}, which finds trace snapshot number @var{n},
7745counting from zero. If no argument @var{n} is given, the next
7746snapshot is selected.
7747
7748Here are the various forms of using the @code{tfind} command.
7749
7750@table @code
7751@item tfind start
7752Find the first snapshot in the buffer. This is a synonym for
7753@code{tfind 0} (since 0 is the number of the first snapshot).
7754
7755@item tfind none
7756Stop debugging trace snapshots, resume @emph{live} debugging.
7757
7758@item tfind end
7759Same as @samp{tfind none}.
7760
7761@item tfind
7762No argument means find the next trace snapshot.
7763
7764@item tfind -
7765Find the previous trace snapshot before the current one. This permits
7766retracing earlier steps.
7767
7768@item tfind tracepoint @var{num}
7769Find the next snapshot associated with tracepoint @var{num}. Search
7770proceeds forward from the last examined trace snapshot. If no
7771argument @var{num} is given, it means find the next snapshot collected
7772for the same tracepoint as the current snapshot.
7773
7774@item tfind pc @var{addr}
7775Find the next snapshot associated with the value @var{addr} of the
7776program counter. Search proceeds forward from the last examined trace
7777snapshot. If no argument @var{addr} is given, it means find the next
7778snapshot with the same value of PC as the current snapshot.
7779
7780@item tfind outside @var{addr1}, @var{addr2}
7781Find the next snapshot whose PC is outside the given range of
7782addresses.
7783
7784@item tfind range @var{addr1}, @var{addr2}
7785Find the next snapshot whose PC is between @var{addr1} and
7786@var{addr2}. @c FIXME: Is the range inclusive or exclusive?
7787
7788@item tfind line @r{[}@var{file}:@r{]}@var{n}
7789Find the next snapshot associated with the source line @var{n}. If
7790the optional argument @var{file} is given, refer to line @var{n} in
7791that source file. Search proceeds forward from the last examined
7792trace snapshot. If no argument @var{n} is given, it means find the
7793next line other than the one currently being examined; thus saying
7794@code{tfind line} repeatedly can appear to have the same effect as
7795stepping from line to line in a @emph{live} debugging session.
7796@end table
7797
7798The default arguments for the @code{tfind} commands are specifically
7799designed to make it easy to scan through the trace buffer. For
7800instance, @code{tfind} with no argument selects the next trace
7801snapshot, and @code{tfind -} with no argument selects the previous
7802trace snapshot. So, by giving one @code{tfind} command, and then
7803simply hitting @key{RET} repeatedly you can examine all the trace
7804snapshots in order. Or, by saying @code{tfind -} and then hitting
7805@key{RET} repeatedly you can examine the snapshots in reverse order.
7806The @code{tfind line} command with no argument selects the snapshot
7807for the next source line executed. The @code{tfind pc} command with
7808no argument selects the next snapshot with the same program counter
7809(PC) as the current frame. The @code{tfind tracepoint} command with
7810no argument selects the next trace snapshot collected by the same
7811tracepoint as the current one.
7812
7813In addition to letting you scan through the trace buffer manually,
7814these commands make it easy to construct @value{GDBN} scripts that
7815scan through the trace buffer and print out whatever collected data
7816you are interested in. Thus, if we want to examine the PC, FP, and SP
7817registers from each trace frame in the buffer, we can say this:
7818
7819@smallexample
7820(@value{GDBP}) @b{tfind start}
7821(@value{GDBP}) @b{while ($trace_frame != -1)}
7822> printf "Frame %d, PC = %08X, SP = %08X, FP = %08X\n", \
7823 $trace_frame, $pc, $sp, $fp
7824> tfind
7825> end
7826
7827Frame 0, PC = 0020DC64, SP = 0030BF3C, FP = 0030BF44
7828Frame 1, PC = 0020DC6C, SP = 0030BF38, FP = 0030BF44
7829Frame 2, PC = 0020DC70, SP = 0030BF34, FP = 0030BF44
7830Frame 3, PC = 0020DC74, SP = 0030BF30, FP = 0030BF44
7831Frame 4, PC = 0020DC78, SP = 0030BF2C, FP = 0030BF44
7832Frame 5, PC = 0020DC7C, SP = 0030BF28, FP = 0030BF44
7833Frame 6, PC = 0020DC80, SP = 0030BF24, FP = 0030BF44
7834Frame 7, PC = 0020DC84, SP = 0030BF20, FP = 0030BF44
7835Frame 8, PC = 0020DC88, SP = 0030BF1C, FP = 0030BF44
7836Frame 9, PC = 0020DC8E, SP = 0030BF18, FP = 0030BF44
7837Frame 10, PC = 00203F6C, SP = 0030BE3C, FP = 0030BF14
7838@end smallexample
7839
7840Or, if we want to examine the variable @code{X} at each source line in
7841the buffer:
7842
7843@smallexample
7844(@value{GDBP}) @b{tfind start}
7845(@value{GDBP}) @b{while ($trace_frame != -1)}
7846> printf "Frame %d, X == %d\n", $trace_frame, X
7847> tfind line
7848> end
7849
7850Frame 0, X = 1
7851Frame 7, X = 2
7852Frame 13, X = 255
7853@end smallexample
7854
7855@node tdump
7856@subsection @code{tdump}
7857@kindex tdump
7858@cindex dump all data collected at tracepoint
7859@cindex tracepoint data, display
7860
7861This command takes no arguments. It prints all the data collected at
7862the current trace snapshot.
7863
7864@smallexample
7865(@value{GDBP}) @b{trace 444}
7866(@value{GDBP}) @b{actions}
7867Enter actions for tracepoint #2, one per line:
7868> collect $regs, $locals, $args, gdb_long_test
7869> end
7870
7871(@value{GDBP}) @b{tstart}
7872
7873(@value{GDBP}) @b{tfind line 444}
7874#0 gdb_test (p1=0x11, p2=0x22, p3=0x33, p4=0x44, p5=0x55, p6=0x66)
7875at gdb_test.c:444
7876444 printp( "%s: arguments = 0x%X 0x%X 0x%X 0x%X 0x%X 0x%X\n", )
7877
7878(@value{GDBP}) @b{tdump}
7879Data collected at tracepoint 2, trace frame 1:
7880d0 0xc4aa0085 -995491707
7881d1 0x18 24
7882d2 0x80 128
7883d3 0x33 51
7884d4 0x71aea3d 119204413
7885d5 0x22 34
7886d6 0xe0 224
7887d7 0x380035 3670069
7888a0 0x19e24a 1696330
7889a1 0x3000668 50333288
7890a2 0x100 256
7891a3 0x322000 3284992
7892a4 0x3000698 50333336
7893a5 0x1ad3cc 1758156
7894fp 0x30bf3c 0x30bf3c
7895sp 0x30bf34 0x30bf34
7896ps 0x0 0
7897pc 0x20b2c8 0x20b2c8
7898fpcontrol 0x0 0
7899fpstatus 0x0 0
7900fpiaddr 0x0 0
7901p = 0x20e5b4 "gdb-test"
7902p1 = (void *) 0x11
7903p2 = (void *) 0x22
7904p3 = (void *) 0x33
7905p4 = (void *) 0x44
7906p5 = (void *) 0x55
7907p6 = (void *) 0x66
7908gdb_long_test = 17 '\021'
7909
7910(@value{GDBP})
7911@end smallexample
7912
7913@node save-tracepoints
7914@subsection @code{save-tracepoints @var{filename}}
7915@kindex save-tracepoints
7916@cindex save tracepoints for future sessions
7917
7918This command saves all current tracepoint definitions together with
7919their actions and passcounts, into a file @file{@var{filename}}
7920suitable for use in a later debugging session. To read the saved
7921tracepoint definitions, use the @code{source} command (@pxref{Command
7922Files}).
7923
7924@node Tracepoint Variables
7925@section Convenience Variables for Tracepoints
7926@cindex tracepoint variables
7927@cindex convenience variables for tracepoints
7928
7929@table @code
7930@vindex $trace_frame
7931@item (int) $trace_frame
7932The current trace snapshot (a.k.a.@: @dfn{frame}) number, or -1 if no
7933snapshot is selected.
7934
7935@vindex $tracepoint
7936@item (int) $tracepoint
7937The tracepoint for the current trace snapshot.
7938
7939@vindex $trace_line
7940@item (int) $trace_line
7941The line number for the current trace snapshot.
7942
7943@vindex $trace_file
7944@item (char []) $trace_file
7945The source file for the current trace snapshot.
7946
7947@vindex $trace_func
7948@item (char []) $trace_func
7949The name of the function containing @code{$tracepoint}.
7950@end table
7951
7952Note: @code{$trace_file} is not suitable for use in @code{printf},
7953use @code{output} instead.
7954
7955Here's a simple example of using these convenience variables for
7956stepping through all the trace snapshots and printing some of their
7957data.
7958
7959@smallexample
7960(@value{GDBP}) @b{tfind start}
7961
7962(@value{GDBP}) @b{while $trace_frame != -1}
7963> output $trace_file
7964> printf ", line %d (tracepoint #%d)\n", $trace_line, $tracepoint
7965> tfind
7966> end
7967@end smallexample
7968
df0cd8c5
JB
7969@node Overlays
7970@chapter Debugging Programs That Use Overlays
7971@cindex overlays
7972
7973If your program is too large to fit completely in your target system's
7974memory, you can sometimes use @dfn{overlays} to work around this
7975problem. @value{GDBN} provides some support for debugging programs that
7976use overlays.
7977
7978@menu
7979* How Overlays Work:: A general explanation of overlays.
7980* Overlay Commands:: Managing overlays in @value{GDBN}.
7981* Automatic Overlay Debugging:: @value{GDBN} can find out which overlays are
7982 mapped by asking the inferior.
7983* Overlay Sample Program:: A sample program using overlays.
7984@end menu
7985
7986@node How Overlays Work
7987@section How Overlays Work
7988@cindex mapped overlays
7989@cindex unmapped overlays
7990@cindex load address, overlay's
7991@cindex mapped address
7992@cindex overlay area
7993
7994Suppose you have a computer whose instruction address space is only 64
7995kilobytes long, but which has much more memory which can be accessed by
7996other means: special instructions, segment registers, or memory
7997management hardware, for example. Suppose further that you want to
7998adapt a program which is larger than 64 kilobytes to run on this system.
7999
8000One solution is to identify modules of your program which are relatively
8001independent, and need not call each other directly; call these modules
8002@dfn{overlays}. Separate the overlays from the main program, and place
8003their machine code in the larger memory. Place your main program in
8004instruction memory, but leave at least enough space there to hold the
8005largest overlay as well.
8006
8007Now, to call a function located in an overlay, you must first copy that
8008overlay's machine code from the large memory into the space set aside
8009for it in the instruction memory, and then jump to its entry point
8010there.
8011
c928edc0
AC
8012@c NB: In the below the mapped area's size is greater or equal to the
8013@c size of all overlays. This is intentional to remind the developer
8014@c that overlays don't necessarily need to be the same size.
8015
474c8240 8016@smallexample
df0cd8c5 8017@group
c928edc0
AC
8018 Data Instruction Larger
8019Address Space Address Space Address Space
8020+-----------+ +-----------+ +-----------+
8021| | | | | |
8022+-----------+ +-----------+ +-----------+<-- overlay 1
8023| program | | main | .----| overlay 1 | load address
8024| variables | | program | | +-----------+
8025| and heap | | | | | |
8026+-----------+ | | | +-----------+<-- overlay 2
8027| | +-----------+ | | | load address
8028+-----------+ | | | .-| overlay 2 |
8029 | | | | | |
8030 mapped --->+-----------+ | | +-----------+
8031 address | | | | | |
8032 | overlay | <-' | | |
8033 | area | <---' +-----------+<-- overlay 3
8034 | | <---. | | load address
8035 +-----------+ `--| overlay 3 |
8036 | | | |
8037 +-----------+ | |
8038 +-----------+
8039 | |
8040 +-----------+
8041
8042 @anchor{A code overlay}A code overlay
df0cd8c5 8043@end group
474c8240 8044@end smallexample
df0cd8c5 8045
c928edc0
AC
8046The diagram (@pxref{A code overlay}) shows a system with separate data
8047and instruction address spaces. To map an overlay, the program copies
8048its code from the larger address space to the instruction address space.
8049Since the overlays shown here all use the same mapped address, only one
8050may be mapped at a time. For a system with a single address space for
8051data and instructions, the diagram would be similar, except that the
8052program variables and heap would share an address space with the main
8053program and the overlay area.
df0cd8c5
JB
8054
8055An overlay loaded into instruction memory and ready for use is called a
8056@dfn{mapped} overlay; its @dfn{mapped address} is its address in the
8057instruction memory. An overlay not present (or only partially present)
8058in instruction memory is called @dfn{unmapped}; its @dfn{load address}
8059is its address in the larger memory. The mapped address is also called
8060the @dfn{virtual memory address}, or @dfn{VMA}; the load address is also
8061called the @dfn{load memory address}, or @dfn{LMA}.
8062
8063Unfortunately, overlays are not a completely transparent way to adapt a
8064program to limited instruction memory. They introduce a new set of
8065global constraints you must keep in mind as you design your program:
8066
8067@itemize @bullet
8068
8069@item
8070Before calling or returning to a function in an overlay, your program
8071must make sure that overlay is actually mapped. Otherwise, the call or
8072return will transfer control to the right address, but in the wrong
8073overlay, and your program will probably crash.
8074
8075@item
8076If the process of mapping an overlay is expensive on your system, you
8077will need to choose your overlays carefully to minimize their effect on
8078your program's performance.
8079
8080@item
8081The executable file you load onto your system must contain each
8082overlay's instructions, appearing at the overlay's load address, not its
8083mapped address. However, each overlay's instructions must be relocated
8084and its symbols defined as if the overlay were at its mapped address.
8085You can use GNU linker scripts to specify different load and relocation
8086addresses for pieces of your program; see @ref{Overlay Description,,,
8087ld.info, Using ld: the GNU linker}.
8088
8089@item
8090The procedure for loading executable files onto your system must be able
8091to load their contents into the larger address space as well as the
8092instruction and data spaces.
8093
8094@end itemize
8095
8096The overlay system described above is rather simple, and could be
8097improved in many ways:
8098
8099@itemize @bullet
8100
8101@item
8102If your system has suitable bank switch registers or memory management
8103hardware, you could use those facilities to make an overlay's load area
8104contents simply appear at their mapped address in instruction space.
8105This would probably be faster than copying the overlay to its mapped
8106area in the usual way.
8107
8108@item
8109If your overlays are small enough, you could set aside more than one
8110overlay area, and have more than one overlay mapped at a time.
8111
8112@item
8113You can use overlays to manage data, as well as instructions. In
8114general, data overlays are even less transparent to your design than
8115code overlays: whereas code overlays only require care when you call or
8116return to functions, data overlays require care every time you access
8117the data. Also, if you change the contents of a data overlay, you
8118must copy its contents back out to its load address before you can copy a
8119different data overlay into the same mapped area.
8120
8121@end itemize
8122
8123
8124@node Overlay Commands
8125@section Overlay Commands
8126
8127To use @value{GDBN}'s overlay support, each overlay in your program must
8128correspond to a separate section of the executable file. The section's
8129virtual memory address and load memory address must be the overlay's
8130mapped and load addresses. Identifying overlays with sections allows
8131@value{GDBN} to determine the appropriate address of a function or
8132variable, depending on whether the overlay is mapped or not.
8133
8134@value{GDBN}'s overlay commands all start with the word @code{overlay};
8135you can abbreviate this as @code{ov} or @code{ovly}. The commands are:
8136
8137@table @code
8138@item overlay off
4644b6e3 8139@kindex overlay
df0cd8c5
JB
8140Disable @value{GDBN}'s overlay support. When overlay support is
8141disabled, @value{GDBN} assumes that all functions and variables are
8142always present at their mapped addresses. By default, @value{GDBN}'s
8143overlay support is disabled.
8144
8145@item overlay manual
df0cd8c5
JB
8146@cindex manual overlay debugging
8147Enable @dfn{manual} overlay debugging. In this mode, @value{GDBN}
8148relies on you to tell it which overlays are mapped, and which are not,
8149using the @code{overlay map-overlay} and @code{overlay unmap-overlay}
8150commands described below.
8151
8152@item overlay map-overlay @var{overlay}
8153@itemx overlay map @var{overlay}
df0cd8c5
JB
8154@cindex map an overlay
8155Tell @value{GDBN} that @var{overlay} is now mapped; @var{overlay} must
8156be the name of the object file section containing the overlay. When an
8157overlay is mapped, @value{GDBN} assumes it can find the overlay's
8158functions and variables at their mapped addresses. @value{GDBN} assumes
8159that any other overlays whose mapped ranges overlap that of
8160@var{overlay} are now unmapped.
8161
8162@item overlay unmap-overlay @var{overlay}
8163@itemx overlay unmap @var{overlay}
df0cd8c5
JB
8164@cindex unmap an overlay
8165Tell @value{GDBN} that @var{overlay} is no longer mapped; @var{overlay}
8166must be the name of the object file section containing the overlay.
8167When an overlay is unmapped, @value{GDBN} assumes it can find the
8168overlay's functions and variables at their load addresses.
8169
8170@item overlay auto
df0cd8c5
JB
8171Enable @dfn{automatic} overlay debugging. In this mode, @value{GDBN}
8172consults a data structure the overlay manager maintains in the inferior
8173to see which overlays are mapped. For details, see @ref{Automatic
8174Overlay Debugging}.
8175
8176@item overlay load-target
8177@itemx overlay load
df0cd8c5
JB
8178@cindex reloading the overlay table
8179Re-read the overlay table from the inferior. Normally, @value{GDBN}
8180re-reads the table @value{GDBN} automatically each time the inferior
8181stops, so this command should only be necessary if you have changed the
8182overlay mapping yourself using @value{GDBN}. This command is only
8183useful when using automatic overlay debugging.
8184
8185@item overlay list-overlays
8186@itemx overlay list
8187@cindex listing mapped overlays
8188Display a list of the overlays currently mapped, along with their mapped
8189addresses, load addresses, and sizes.
8190
8191@end table
8192
8193Normally, when @value{GDBN} prints a code address, it includes the name
8194of the function the address falls in:
8195
474c8240 8196@smallexample
f7dc1244 8197(@value{GDBP}) print main
df0cd8c5 8198$3 = @{int ()@} 0x11a0 <main>
474c8240 8199@end smallexample
df0cd8c5
JB
8200@noindent
8201When overlay debugging is enabled, @value{GDBN} recognizes code in
8202unmapped overlays, and prints the names of unmapped functions with
8203asterisks around them. For example, if @code{foo} is a function in an
8204unmapped overlay, @value{GDBN} prints it this way:
8205
474c8240 8206@smallexample
f7dc1244 8207(@value{GDBP}) overlay list
df0cd8c5 8208No sections are mapped.
f7dc1244 8209(@value{GDBP}) print foo
df0cd8c5 8210$5 = @{int (int)@} 0x100000 <*foo*>
474c8240 8211@end smallexample
df0cd8c5
JB
8212@noindent
8213When @code{foo}'s overlay is mapped, @value{GDBN} prints the function's
8214name normally:
8215
474c8240 8216@smallexample
f7dc1244 8217(@value{GDBP}) overlay list
b383017d 8218Section .ov.foo.text, loaded at 0x100000 - 0x100034,
df0cd8c5 8219 mapped at 0x1016 - 0x104a
f7dc1244 8220(@value{GDBP}) print foo
df0cd8c5 8221$6 = @{int (int)@} 0x1016 <foo>
474c8240 8222@end smallexample
df0cd8c5
JB
8223
8224When overlay debugging is enabled, @value{GDBN} can find the correct
8225address for functions and variables in an overlay, whether or not the
8226overlay is mapped. This allows most @value{GDBN} commands, like
8227@code{break} and @code{disassemble}, to work normally, even on unmapped
8228code. However, @value{GDBN}'s breakpoint support has some limitations:
8229
8230@itemize @bullet
8231@item
8232@cindex breakpoints in overlays
8233@cindex overlays, setting breakpoints in
8234You can set breakpoints in functions in unmapped overlays, as long as
8235@value{GDBN} can write to the overlay at its load address.
8236@item
8237@value{GDBN} can not set hardware or simulator-based breakpoints in
8238unmapped overlays. However, if you set a breakpoint at the end of your
8239overlay manager (and tell @value{GDBN} which overlays are now mapped, if
8240you are using manual overlay management), @value{GDBN} will re-set its
8241breakpoints properly.
8242@end itemize
8243
8244
8245@node Automatic Overlay Debugging
8246@section Automatic Overlay Debugging
8247@cindex automatic overlay debugging
8248
8249@value{GDBN} can automatically track which overlays are mapped and which
8250are not, given some simple co-operation from the overlay manager in the
8251inferior. If you enable automatic overlay debugging with the
8252@code{overlay auto} command (@pxref{Overlay Commands}), @value{GDBN}
8253looks in the inferior's memory for certain variables describing the
8254current state of the overlays.
8255
8256Here are the variables your overlay manager must define to support
8257@value{GDBN}'s automatic overlay debugging:
8258
8259@table @asis
8260
8261@item @code{_ovly_table}:
8262This variable must be an array of the following structures:
8263
474c8240 8264@smallexample
df0cd8c5
JB
8265struct
8266@{
8267 /* The overlay's mapped address. */
8268 unsigned long vma;
8269
8270 /* The size of the overlay, in bytes. */
8271 unsigned long size;
8272
8273 /* The overlay's load address. */
8274 unsigned long lma;
8275
8276 /* Non-zero if the overlay is currently mapped;
8277 zero otherwise. */
8278 unsigned long mapped;
8279@}
474c8240 8280@end smallexample
df0cd8c5
JB
8281
8282@item @code{_novlys}:
8283This variable must be a four-byte signed integer, holding the total
8284number of elements in @code{_ovly_table}.
8285
8286@end table
8287
8288To decide whether a particular overlay is mapped or not, @value{GDBN}
8289looks for an entry in @w{@code{_ovly_table}} whose @code{vma} and
8290@code{lma} members equal the VMA and LMA of the overlay's section in the
8291executable file. When @value{GDBN} finds a matching entry, it consults
8292the entry's @code{mapped} member to determine whether the overlay is
8293currently mapped.
8294
81d46470 8295In addition, your overlay manager may define a function called
def71bfa 8296@code{_ovly_debug_event}. If this function is defined, @value{GDBN}
81d46470
MS
8297will silently set a breakpoint there. If the overlay manager then
8298calls this function whenever it has changed the overlay table, this
8299will enable @value{GDBN} to accurately keep track of which overlays
8300are in program memory, and update any breakpoints that may be set
b383017d 8301in overlays. This will allow breakpoints to work even if the
81d46470
MS
8302overlays are kept in ROM or other non-writable memory while they
8303are not being executed.
df0cd8c5
JB
8304
8305@node Overlay Sample Program
8306@section Overlay Sample Program
8307@cindex overlay example program
8308
8309When linking a program which uses overlays, you must place the overlays
8310at their load addresses, while relocating them to run at their mapped
8311addresses. To do this, you must write a linker script (@pxref{Overlay
8312Description,,, ld.info, Using ld: the GNU linker}). Unfortunately,
8313since linker scripts are specific to a particular host system, target
8314architecture, and target memory layout, this manual cannot provide
8315portable sample code demonstrating @value{GDBN}'s overlay support.
8316
8317However, the @value{GDBN} source distribution does contain an overlaid
8318program, with linker scripts for a few systems, as part of its test
8319suite. The program consists of the following files from
8320@file{gdb/testsuite/gdb.base}:
8321
8322@table @file
8323@item overlays.c
8324The main program file.
8325@item ovlymgr.c
8326A simple overlay manager, used by @file{overlays.c}.
8327@item foo.c
8328@itemx bar.c
8329@itemx baz.c
8330@itemx grbx.c
8331Overlay modules, loaded and used by @file{overlays.c}.
8332@item d10v.ld
8333@itemx m32r.ld
8334Linker scripts for linking the test program on the @code{d10v-elf}
8335and @code{m32r-elf} targets.
8336@end table
8337
8338You can build the test program using the @code{d10v-elf} GCC
8339cross-compiler like this:
8340
474c8240 8341@smallexample
df0cd8c5
JB
8342$ d10v-elf-gcc -g -c overlays.c
8343$ d10v-elf-gcc -g -c ovlymgr.c
8344$ d10v-elf-gcc -g -c foo.c
8345$ d10v-elf-gcc -g -c bar.c
8346$ d10v-elf-gcc -g -c baz.c
8347$ d10v-elf-gcc -g -c grbx.c
8348$ d10v-elf-gcc -g overlays.o ovlymgr.o foo.o bar.o \
8349 baz.o grbx.o -Wl,-Td10v.ld -o overlays
474c8240 8350@end smallexample
df0cd8c5
JB
8351
8352The build process is identical for any other architecture, except that
8353you must substitute the appropriate compiler and linker script for the
8354target system for @code{d10v-elf-gcc} and @code{d10v.ld}.
8355
8356
6d2ebf8b 8357@node Languages
c906108c
SS
8358@chapter Using @value{GDBN} with Different Languages
8359@cindex languages
8360
c906108c
SS
8361Although programming languages generally have common aspects, they are
8362rarely expressed in the same manner. For instance, in ANSI C,
8363dereferencing a pointer @code{p} is accomplished by @code{*p}, but in
8364Modula-2, it is accomplished by @code{p^}. Values can also be
5d161b24 8365represented (and displayed) differently. Hex numbers in C appear as
c906108c 8366@samp{0x1ae}, while in Modula-2 they appear as @samp{1AEH}.
c906108c
SS
8367
8368@cindex working language
8369Language-specific information is built into @value{GDBN} for some languages,
8370allowing you to express operations like the above in your program's
8371native language, and allowing @value{GDBN} to output values in a manner
8372consistent with the syntax of your program's native language. The
8373language you use to build expressions is called the @dfn{working
8374language}.
8375
8376@menu
8377* Setting:: Switching between source languages
8378* Show:: Displaying the language
c906108c 8379* Checks:: Type and range checks
9c16f35a 8380* Supported languages:: Supported languages
4e562065 8381* Unsupported languages:: Unsupported languages
c906108c
SS
8382@end menu
8383
6d2ebf8b 8384@node Setting
c906108c
SS
8385@section Switching between source languages
8386
8387There are two ways to control the working language---either have @value{GDBN}
8388set it automatically, or select it manually yourself. You can use the
8389@code{set language} command for either purpose. On startup, @value{GDBN}
8390defaults to setting the language automatically. The working language is
8391used to determine how expressions you type are interpreted, how values
8392are printed, etc.
8393
8394In addition to the working language, every source file that
8395@value{GDBN} knows about has its own working language. For some object
8396file formats, the compiler might indicate which language a particular
8397source file is in. However, most of the time @value{GDBN} infers the
8398language from the name of the file. The language of a source file
b37052ae 8399controls whether C@t{++} names are demangled---this way @code{backtrace} can
c906108c 8400show each frame appropriately for its own language. There is no way to
d4f3574e
SS
8401set the language of a source file from within @value{GDBN}, but you can
8402set the language associated with a filename extension. @xref{Show, ,
8403Displaying the language}.
c906108c
SS
8404
8405This is most commonly a problem when you use a program, such
5d161b24 8406as @code{cfront} or @code{f2c}, that generates C but is written in
c906108c
SS
8407another language. In that case, make the
8408program use @code{#line} directives in its C output; that way
8409@value{GDBN} will know the correct language of the source code of the original
8410program, and will display that source code, not the generated C code.
8411
8412@menu
8413* Filenames:: Filename extensions and languages.
8414* Manually:: Setting the working language manually
8415* Automatically:: Having @value{GDBN} infer the source language
8416@end menu
8417
6d2ebf8b 8418@node Filenames
c906108c
SS
8419@subsection List of filename extensions and languages
8420
8421If a source file name ends in one of the following extensions, then
8422@value{GDBN} infers that its language is the one indicated.
8423
8424@table @file
e07c999f
PH
8425@item .ada
8426@itemx .ads
8427@itemx .adb
8428@itemx .a
8429Ada source file.
c906108c
SS
8430
8431@item .c
8432C source file
8433
8434@item .C
8435@itemx .cc
8436@itemx .cp
8437@itemx .cpp
8438@itemx .cxx
8439@itemx .c++
b37052ae 8440C@t{++} source file
c906108c 8441
b37303ee
AF
8442@item .m
8443Objective-C source file
8444
c906108c
SS
8445@item .f
8446@itemx .F
8447Fortran source file
8448
c906108c
SS
8449@item .mod
8450Modula-2 source file
c906108c
SS
8451
8452@item .s
8453@itemx .S
8454Assembler source file. This actually behaves almost like C, but
8455@value{GDBN} does not skip over function prologues when stepping.
8456@end table
8457
8458In addition, you may set the language associated with a filename
8459extension. @xref{Show, , Displaying the language}.
8460
6d2ebf8b 8461@node Manually
c906108c
SS
8462@subsection Setting the working language
8463
8464If you allow @value{GDBN} to set the language automatically,
8465expressions are interpreted the same way in your debugging session and
8466your program.
8467
8468@kindex set language
8469If you wish, you may set the language manually. To do this, issue the
8470command @samp{set language @var{lang}}, where @var{lang} is the name of
5d161b24 8471a language, such as
c906108c 8472@code{c} or @code{modula-2}.
c906108c
SS
8473For a list of the supported languages, type @samp{set language}.
8474
c906108c
SS
8475Setting the language manually prevents @value{GDBN} from updating the working
8476language automatically. This can lead to confusion if you try
8477to debug a program when the working language is not the same as the
8478source language, when an expression is acceptable to both
8479languages---but means different things. For instance, if the current
8480source file were written in C, and @value{GDBN} was parsing Modula-2, a
8481command such as:
8482
474c8240 8483@smallexample
c906108c 8484print a = b + c
474c8240 8485@end smallexample
c906108c
SS
8486
8487@noindent
8488might not have the effect you intended. In C, this means to add
8489@code{b} and @code{c} and place the result in @code{a}. The result
8490printed would be the value of @code{a}. In Modula-2, this means to compare
8491@code{a} to the result of @code{b+c}, yielding a @code{BOOLEAN} value.
c906108c 8492
6d2ebf8b 8493@node Automatically
c906108c
SS
8494@subsection Having @value{GDBN} infer the source language
8495
8496To have @value{GDBN} set the working language automatically, use
8497@samp{set language local} or @samp{set language auto}. @value{GDBN}
8498then infers the working language. That is, when your program stops in a
8499frame (usually by encountering a breakpoint), @value{GDBN} sets the
8500working language to the language recorded for the function in that
8501frame. If the language for a frame is unknown (that is, if the function
8502or block corresponding to the frame was defined in a source file that
8503does not have a recognized extension), the current working language is
8504not changed, and @value{GDBN} issues a warning.
8505
8506This may not seem necessary for most programs, which are written
8507entirely in one source language. However, program modules and libraries
8508written in one source language can be used by a main program written in
8509a different source language. Using @samp{set language auto} in this
8510case frees you from having to set the working language manually.
8511
6d2ebf8b 8512@node Show
c906108c 8513@section Displaying the language
c906108c
SS
8514
8515The following commands help you find out which language is the
8516working language, and also what language source files were written in.
8517
c906108c
SS
8518@table @code
8519@item show language
9c16f35a 8520@kindex show language
c906108c
SS
8521Display the current working language. This is the
8522language you can use with commands such as @code{print} to
8523build and compute expressions that may involve variables in your program.
8524
8525@item info frame
4644b6e3 8526@kindex info frame@r{, show the source language}
5d161b24 8527Display the source language for this frame. This language becomes the
c906108c 8528working language if you use an identifier from this frame.
5d161b24 8529@xref{Frame Info, ,Information about a frame}, to identify the other
c906108c
SS
8530information listed here.
8531
8532@item info source
4644b6e3 8533@kindex info source@r{, show the source language}
c906108c 8534Display the source language of this source file.
5d161b24 8535@xref{Symbols, ,Examining the Symbol Table}, to identify the other
c906108c
SS
8536information listed here.
8537@end table
8538
8539In unusual circumstances, you may have source files with extensions
8540not in the standard list. You can then set the extension associated
8541with a language explicitly:
8542
c906108c 8543@table @code
09d4efe1 8544@item set extension-language @var{ext} @var{language}
9c16f35a 8545@kindex set extension-language
09d4efe1
EZ
8546Tell @value{GDBN} that source files with extension @var{ext} are to be
8547assumed as written in the source language @var{language}.
c906108c
SS
8548
8549@item info extensions
9c16f35a 8550@kindex info extensions
c906108c
SS
8551List all the filename extensions and the associated languages.
8552@end table
8553
6d2ebf8b 8554@node Checks
c906108c
SS
8555@section Type and range checking
8556
8557@quotation
8558@emph{Warning:} In this release, the @value{GDBN} commands for type and range
8559checking are included, but they do not yet have any effect. This
8560section documents the intended facilities.
8561@end quotation
8562@c FIXME remove warning when type/range code added
8563
8564Some languages are designed to guard you against making seemingly common
8565errors through a series of compile- and run-time checks. These include
8566checking the type of arguments to functions and operators, and making
8567sure mathematical overflows are caught at run time. Checks such as
8568these help to ensure a program's correctness once it has been compiled
8569by eliminating type mismatches, and providing active checks for range
8570errors when your program is running.
8571
8572@value{GDBN} can check for conditions like the above if you wish.
9c16f35a
EZ
8573Although @value{GDBN} does not check the statements in your program,
8574it can check expressions entered directly into @value{GDBN} for
8575evaluation via the @code{print} command, for example. As with the
8576working language, @value{GDBN} can also decide whether or not to check
8577automatically based on your program's source language.
8578@xref{Supported languages, ,Supported languages}, for the default
8579settings of supported languages.
c906108c
SS
8580
8581@menu
8582* Type Checking:: An overview of type checking
8583* Range Checking:: An overview of range checking
8584@end menu
8585
8586@cindex type checking
8587@cindex checks, type
6d2ebf8b 8588@node Type Checking
c906108c
SS
8589@subsection An overview of type checking
8590
8591Some languages, such as Modula-2, are strongly typed, meaning that the
8592arguments to operators and functions have to be of the correct type,
8593otherwise an error occurs. These checks prevent type mismatch
8594errors from ever causing any run-time problems. For example,
8595
8596@smallexample
85971 + 2 @result{} 3
8598@exdent but
8599@error{} 1 + 2.3
8600@end smallexample
8601
8602The second example fails because the @code{CARDINAL} 1 is not
8603type-compatible with the @code{REAL} 2.3.
8604
5d161b24
DB
8605For the expressions you use in @value{GDBN} commands, you can tell the
8606@value{GDBN} type checker to skip checking;
8607to treat any mismatches as errors and abandon the expression;
8608or to only issue warnings when type mismatches occur,
c906108c
SS
8609but evaluate the expression anyway. When you choose the last of
8610these, @value{GDBN} evaluates expressions like the second example above, but
8611also issues a warning.
8612
5d161b24
DB
8613Even if you turn type checking off, there may be other reasons
8614related to type that prevent @value{GDBN} from evaluating an expression.
8615For instance, @value{GDBN} does not know how to add an @code{int} and
8616a @code{struct foo}. These particular type errors have nothing to do
8617with the language in use, and usually arise from expressions, such as
c906108c
SS
8618the one described above, which make little sense to evaluate anyway.
8619
8620Each language defines to what degree it is strict about type. For
8621instance, both Modula-2 and C require the arguments to arithmetical
8622operators to be numbers. In C, enumerated types and pointers can be
8623represented as numbers, so that they are valid arguments to mathematical
9c16f35a 8624operators. @xref{Supported languages, ,Supported languages}, for further
c906108c
SS
8625details on specific languages.
8626
8627@value{GDBN} provides some additional commands for controlling the type checker:
8628
c906108c
SS
8629@kindex set check type
8630@kindex show check type
8631@table @code
8632@item set check type auto
8633Set type checking on or off based on the current working language.
9c16f35a 8634@xref{Supported languages, ,Supported languages}, for the default settings for
c906108c
SS
8635each language.
8636
8637@item set check type on
8638@itemx set check type off
8639Set type checking on or off, overriding the default setting for the
8640current working language. Issue a warning if the setting does not
8641match the language default. If any type mismatches occur in
d4f3574e 8642evaluating an expression while type checking is on, @value{GDBN} prints a
c906108c
SS
8643message and aborts evaluation of the expression.
8644
8645@item set check type warn
8646Cause the type checker to issue warnings, but to always attempt to
8647evaluate the expression. Evaluating the expression may still
8648be impossible for other reasons. For example, @value{GDBN} cannot add
8649numbers and structures.
8650
8651@item show type
5d161b24 8652Show the current setting of the type checker, and whether or not @value{GDBN}
c906108c
SS
8653is setting it automatically.
8654@end table
8655
8656@cindex range checking
8657@cindex checks, range
6d2ebf8b 8658@node Range Checking
c906108c
SS
8659@subsection An overview of range checking
8660
8661In some languages (such as Modula-2), it is an error to exceed the
8662bounds of a type; this is enforced with run-time checks. Such range
8663checking is meant to ensure program correctness by making sure
8664computations do not overflow, or indices on an array element access do
8665not exceed the bounds of the array.
8666
8667For expressions you use in @value{GDBN} commands, you can tell
8668@value{GDBN} to treat range errors in one of three ways: ignore them,
8669always treat them as errors and abandon the expression, or issue
8670warnings but evaluate the expression anyway.
8671
8672A range error can result from numerical overflow, from exceeding an
8673array index bound, or when you type a constant that is not a member
8674of any type. Some languages, however, do not treat overflows as an
8675error. In many implementations of C, mathematical overflow causes the
8676result to ``wrap around'' to lower values---for example, if @var{m} is
8677the largest integer value, and @var{s} is the smallest, then
8678
474c8240 8679@smallexample
c906108c 8680@var{m} + 1 @result{} @var{s}
474c8240 8681@end smallexample
c906108c
SS
8682
8683This, too, is specific to individual languages, and in some cases
9c16f35a 8684specific to individual compilers or machines. @xref{Supported languages, ,
c906108c
SS
8685Supported languages}, for further details on specific languages.
8686
8687@value{GDBN} provides some additional commands for controlling the range checker:
8688
c906108c
SS
8689@kindex set check range
8690@kindex show check range
8691@table @code
8692@item set check range auto
8693Set range checking on or off based on the current working language.
9c16f35a 8694@xref{Supported languages, ,Supported languages}, for the default settings for
c906108c
SS
8695each language.
8696
8697@item set check range on
8698@itemx set check range off
8699Set range checking on or off, overriding the default setting for the
8700current working language. A warning is issued if the setting does not
c3f6f71d
JM
8701match the language default. If a range error occurs and range checking is on,
8702then a message is printed and evaluation of the expression is aborted.
c906108c
SS
8703
8704@item set check range warn
8705Output messages when the @value{GDBN} range checker detects a range error,
8706but attempt to evaluate the expression anyway. Evaluating the
8707expression may still be impossible for other reasons, such as accessing
8708memory that the process does not own (a typical example from many Unix
8709systems).
8710
8711@item show range
8712Show the current setting of the range checker, and whether or not it is
8713being set automatically by @value{GDBN}.
8714@end table
c906108c 8715
9c16f35a 8716@node Supported languages
c906108c 8717@section Supported languages
c906108c 8718
9c16f35a
EZ
8719@value{GDBN} supports C, C@t{++}, Objective-C, Fortran, Java, Pascal,
8720assembly, Modula-2, and Ada.
cce74817 8721@c This is false ...
c906108c
SS
8722Some @value{GDBN} features may be used in expressions regardless of the
8723language you use: the @value{GDBN} @code{@@} and @code{::} operators,
8724and the @samp{@{type@}addr} construct (@pxref{Expressions,
8725,Expressions}) can be used with the constructs of any supported
8726language.
8727
8728The following sections detail to what degree each source language is
8729supported by @value{GDBN}. These sections are not meant to be language
8730tutorials or references, but serve only as a reference guide to what the
8731@value{GDBN} expression parser accepts, and what input and output
8732formats should look like for different languages. There are many good
8733books written on each of these languages; please look to these for a
8734language reference or tutorial.
8735
c906108c 8736@menu
b37303ee 8737* C:: C and C@t{++}
b383017d 8738* Objective-C:: Objective-C
09d4efe1 8739* Fortran:: Fortran
9c16f35a 8740* Pascal:: Pascal
b37303ee 8741* Modula-2:: Modula-2
e07c999f 8742* Ada:: Ada
c906108c
SS
8743@end menu
8744
6d2ebf8b 8745@node C
b37052ae 8746@subsection C and C@t{++}
7a292a7a 8747
b37052ae
EZ
8748@cindex C and C@t{++}
8749@cindex expressions in C or C@t{++}
c906108c 8750
b37052ae 8751Since C and C@t{++} are so closely related, many features of @value{GDBN} apply
c906108c
SS
8752to both languages. Whenever this is the case, we discuss those languages
8753together.
8754
41afff9a
EZ
8755@cindex C@t{++}
8756@cindex @code{g++}, @sc{gnu} C@t{++} compiler
b37052ae
EZ
8757@cindex @sc{gnu} C@t{++}
8758The C@t{++} debugging facilities are jointly implemented by the C@t{++}
8759compiler and @value{GDBN}. Therefore, to debug your C@t{++} code
8760effectively, you must compile your C@t{++} programs with a supported
8761C@t{++} compiler, such as @sc{gnu} @code{g++}, or the HP ANSI C@t{++}
c906108c
SS
8762compiler (@code{aCC}).
8763
0179ffac
DC
8764For best results when using @sc{gnu} C@t{++}, use the DWARF 2 debugging
8765format; if it doesn't work on your system, try the stabs+ debugging
8766format. You can select those formats explicitly with the @code{g++}
8767command-line options @option{-gdwarf-2} and @option{-gstabs+}.
8768@xref{Debugging Options,,Options for Debugging Your Program or @sc{gnu}
8769CC, gcc.info, Using @sc{gnu} CC}.
c906108c 8770
c906108c 8771@menu
b37052ae
EZ
8772* C Operators:: C and C@t{++} operators
8773* C Constants:: C and C@t{++} constants
8774* C plus plus expressions:: C@t{++} expressions
8775* C Defaults:: Default settings for C and C@t{++}
8776* C Checks:: C and C@t{++} type and range checks
c906108c 8777* Debugging C:: @value{GDBN} and C
b37052ae 8778* Debugging C plus plus:: @value{GDBN} features for C@t{++}
c906108c 8779@end menu
c906108c 8780
6d2ebf8b 8781@node C Operators
b37052ae 8782@subsubsection C and C@t{++} operators
7a292a7a 8783
b37052ae 8784@cindex C and C@t{++} operators
c906108c
SS
8785
8786Operators must be defined on values of specific types. For instance,
8787@code{+} is defined on numbers, but not on structures. Operators are
5d161b24 8788often defined on groups of types.
c906108c 8789
b37052ae 8790For the purposes of C and C@t{++}, the following definitions hold:
c906108c
SS
8791
8792@itemize @bullet
53a5351d 8793
c906108c 8794@item
c906108c 8795@emph{Integral types} include @code{int} with any of its storage-class
b37052ae 8796specifiers; @code{char}; @code{enum}; and, for C@t{++}, @code{bool}.
c906108c
SS
8797
8798@item
d4f3574e
SS
8799@emph{Floating-point types} include @code{float}, @code{double}, and
8800@code{long double} (if supported by the target platform).
c906108c
SS
8801
8802@item
53a5351d 8803@emph{Pointer types} include all types defined as @code{(@var{type} *)}.
c906108c
SS
8804
8805@item
8806@emph{Scalar types} include all of the above.
53a5351d 8807
c906108c
SS
8808@end itemize
8809
8810@noindent
8811The following operators are supported. They are listed here
8812in order of increasing precedence:
8813
8814@table @code
8815@item ,
8816The comma or sequencing operator. Expressions in a comma-separated list
8817are evaluated from left to right, with the result of the entire
8818expression being the last expression evaluated.
8819
8820@item =
8821Assignment. The value of an assignment expression is the value
8822assigned. Defined on scalar types.
8823
8824@item @var{op}=
8825Used in an expression of the form @w{@code{@var{a} @var{op}= @var{b}}},
8826and translated to @w{@code{@var{a} = @var{a op b}}}.
d4f3574e 8827@w{@code{@var{op}=}} and @code{=} have the same precedence.
c906108c
SS
8828@var{op} is any one of the operators @code{|}, @code{^}, @code{&},
8829@code{<<}, @code{>>}, @code{+}, @code{-}, @code{*}, @code{/}, @code{%}.
8830
8831@item ?:
8832The ternary operator. @code{@var{a} ? @var{b} : @var{c}} can be thought
8833of as: if @var{a} then @var{b} else @var{c}. @var{a} should be of an
8834integral type.
8835
8836@item ||
8837Logical @sc{or}. Defined on integral types.
8838
8839@item &&
8840Logical @sc{and}. Defined on integral types.
8841
8842@item |
8843Bitwise @sc{or}. Defined on integral types.
8844
8845@item ^
8846Bitwise exclusive-@sc{or}. Defined on integral types.
8847
8848@item &
8849Bitwise @sc{and}. Defined on integral types.
8850
8851@item ==@r{, }!=
8852Equality and inequality. Defined on scalar types. The value of these
8853expressions is 0 for false and non-zero for true.
8854
8855@item <@r{, }>@r{, }<=@r{, }>=
8856Less than, greater than, less than or equal, greater than or equal.
8857Defined on scalar types. The value of these expressions is 0 for false
8858and non-zero for true.
8859
8860@item <<@r{, }>>
8861left shift, and right shift. Defined on integral types.
8862
8863@item @@
8864The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}).
8865
8866@item +@r{, }-
8867Addition and subtraction. Defined on integral types, floating-point types and
8868pointer types.
8869
8870@item *@r{, }/@r{, }%
8871Multiplication, division, and modulus. Multiplication and division are
8872defined on integral and floating-point types. Modulus is defined on
8873integral types.
8874
8875@item ++@r{, }--
8876Increment and decrement. When appearing before a variable, the
8877operation is performed before the variable is used in an expression;
8878when appearing after it, the variable's value is used before the
8879operation takes place.
8880
8881@item *
8882Pointer dereferencing. Defined on pointer types. Same precedence as
8883@code{++}.
8884
8885@item &
8886Address operator. Defined on variables. Same precedence as @code{++}.
8887
b37052ae
EZ
8888For debugging C@t{++}, @value{GDBN} implements a use of @samp{&} beyond what is
8889allowed in the C@t{++} language itself: you can use @samp{&(&@var{ref})}
c906108c 8890(or, if you prefer, simply @samp{&&@var{ref}}) to examine the address
b37052ae 8891where a C@t{++} reference variable (declared with @samp{&@var{ref}}) is
c906108c 8892stored.
c906108c
SS
8893
8894@item -
8895Negative. Defined on integral and floating-point types. Same
8896precedence as @code{++}.
8897
8898@item !
8899Logical negation. Defined on integral types. Same precedence as
8900@code{++}.
8901
8902@item ~
8903Bitwise complement operator. Defined on integral types. Same precedence as
8904@code{++}.
8905
8906
8907@item .@r{, }->
8908Structure member, and pointer-to-structure member. For convenience,
8909@value{GDBN} regards the two as equivalent, choosing whether to dereference a
8910pointer based on the stored type information.
8911Defined on @code{struct} and @code{union} data.
8912
c906108c
SS
8913@item .*@r{, }->*
8914Dereferences of pointers to members.
c906108c
SS
8915
8916@item []
8917Array indexing. @code{@var{a}[@var{i}]} is defined as
8918@code{*(@var{a}+@var{i})}. Same precedence as @code{->}.
8919
8920@item ()
8921Function parameter list. Same precedence as @code{->}.
8922
c906108c 8923@item ::
b37052ae 8924C@t{++} scope resolution operator. Defined on @code{struct}, @code{union},
7a292a7a 8925and @code{class} types.
c906108c
SS
8926
8927@item ::
7a292a7a
SS
8928Doubled colons also represent the @value{GDBN} scope operator
8929(@pxref{Expressions, ,Expressions}). Same precedence as @code{::},
8930above.
c906108c
SS
8931@end table
8932
c906108c
SS
8933If an operator is redefined in the user code, @value{GDBN} usually
8934attempts to invoke the redefined version instead of using the operator's
8935predefined meaning.
c906108c 8936
c906108c 8937@menu
5d161b24 8938* C Constants::
c906108c
SS
8939@end menu
8940
6d2ebf8b 8941@node C Constants
b37052ae 8942@subsubsection C and C@t{++} constants
c906108c 8943
b37052ae 8944@cindex C and C@t{++} constants
c906108c 8945
b37052ae 8946@value{GDBN} allows you to express the constants of C and C@t{++} in the
c906108c 8947following ways:
c906108c
SS
8948
8949@itemize @bullet
8950@item
8951Integer constants are a sequence of digits. Octal constants are
6ca652b0
EZ
8952specified by a leading @samp{0} (i.e.@: zero), and hexadecimal constants
8953by a leading @samp{0x} or @samp{0X}. Constants may also end with a letter
c906108c
SS
8954@samp{l}, specifying that the constant should be treated as a
8955@code{long} value.
8956
8957@item
8958Floating point constants are a sequence of digits, followed by a decimal
8959point, followed by a sequence of digits, and optionally followed by an
8960exponent. An exponent is of the form:
8961@samp{@w{e@r{[[}+@r{]|}-@r{]}@var{nnn}}}, where @var{nnn} is another
8962sequence of digits. The @samp{+} is optional for positive exponents.
d4f3574e
SS
8963A floating-point constant may also end with a letter @samp{f} or
8964@samp{F}, specifying that the constant should be treated as being of
8965the @code{float} (as opposed to the default @code{double}) type; or with
8966a letter @samp{l} or @samp{L}, which specifies a @code{long double}
8967constant.
c906108c
SS
8968
8969@item
8970Enumerated constants consist of enumerated identifiers, or their
8971integral equivalents.
8972
8973@item
8974Character constants are a single character surrounded by single quotes
8975(@code{'}), or a number---the ordinal value of the corresponding character
d4f3574e 8976(usually its @sc{ascii} value). Within quotes, the single character may
c906108c
SS
8977be represented by a letter or by @dfn{escape sequences}, which are of
8978the form @samp{\@var{nnn}}, where @var{nnn} is the octal representation
8979of the character's ordinal value; or of the form @samp{\@var{x}}, where
8980@samp{@var{x}} is a predefined special character---for example,
8981@samp{\n} for newline.
8982
8983@item
96a2c332
SS
8984String constants are a sequence of character constants surrounded by
8985double quotes (@code{"}). Any valid character constant (as described
8986above) may appear. Double quotes within the string must be preceded by
8987a backslash, so for instance @samp{"a\"b'c"} is a string of five
8988characters.
c906108c
SS
8989
8990@item
8991Pointer constants are an integral value. You can also write pointers
8992to constants using the C operator @samp{&}.
8993
8994@item
8995Array constants are comma-separated lists surrounded by braces @samp{@{}
8996and @samp{@}}; for example, @samp{@{1,2,3@}} is a three-element array of
8997integers, @samp{@{@{1,2@}, @{3,4@}, @{5,6@}@}} is a three-by-two array,
8998and @samp{@{&"hi", &"there", &"fred"@}} is a three-element array of pointers.
8999@end itemize
9000
c906108c 9001@menu
5d161b24
DB
9002* C plus plus expressions::
9003* C Defaults::
9004* C Checks::
c906108c 9005
5d161b24 9006* Debugging C::
c906108c
SS
9007@end menu
9008
6d2ebf8b 9009@node C plus plus expressions
b37052ae
EZ
9010@subsubsection C@t{++} expressions
9011
9012@cindex expressions in C@t{++}
9013@value{GDBN} expression handling can interpret most C@t{++} expressions.
9014
0179ffac
DC
9015@cindex debugging C@t{++} programs
9016@cindex C@t{++} compilers
9017@cindex debug formats and C@t{++}
9018@cindex @value{NGCC} and C@t{++}
c906108c 9019@quotation
b37052ae 9020@emph{Warning:} @value{GDBN} can only debug C@t{++} code if you use the
0179ffac
DC
9021proper compiler and the proper debug format. Currently, @value{GDBN}
9022works best when debugging C@t{++} code that is compiled with
9023@value{NGCC} 2.95.3 or with @value{NGCC} 3.1 or newer, using the options
9024@option{-gdwarf-2} or @option{-gstabs+}. DWARF 2 is preferred over
9025stabs+. Most configurations of @value{NGCC} emit either DWARF 2 or
9026stabs+ as their default debug format, so you usually don't need to
9027specify a debug format explicitly. Other compilers and/or debug formats
9028are likely to work badly or not at all when using @value{GDBN} to debug
9029C@t{++} code.
c906108c 9030@end quotation
c906108c
SS
9031
9032@enumerate
9033
9034@cindex member functions
9035@item
9036Member function calls are allowed; you can use expressions like
9037
474c8240 9038@smallexample
c906108c 9039count = aml->GetOriginal(x, y)
474c8240 9040@end smallexample
c906108c 9041
41afff9a 9042@vindex this@r{, inside C@t{++} member functions}
b37052ae 9043@cindex namespace in C@t{++}
c906108c
SS
9044@item
9045While a member function is active (in the selected stack frame), your
9046expressions have the same namespace available as the member function;
9047that is, @value{GDBN} allows implicit references to the class instance
b37052ae 9048pointer @code{this} following the same rules as C@t{++}.
c906108c 9049
c906108c 9050@cindex call overloaded functions
d4f3574e 9051@cindex overloaded functions, calling
b37052ae 9052@cindex type conversions in C@t{++}
c906108c
SS
9053@item
9054You can call overloaded functions; @value{GDBN} resolves the function
d4f3574e 9055call to the right definition, with some restrictions. @value{GDBN} does not
c906108c
SS
9056perform overload resolution involving user-defined type conversions,
9057calls to constructors, or instantiations of templates that do not exist
9058in the program. It also cannot handle ellipsis argument lists or
9059default arguments.
9060
9061It does perform integral conversions and promotions, floating-point
9062promotions, arithmetic conversions, pointer conversions, conversions of
9063class objects to base classes, and standard conversions such as those of
9064functions or arrays to pointers; it requires an exact match on the
9065number of function arguments.
9066
9067Overload resolution is always performed, unless you have specified
9068@code{set overload-resolution off}. @xref{Debugging C plus plus,
b37052ae 9069,@value{GDBN} features for C@t{++}}.
c906108c 9070
d4f3574e 9071You must specify @code{set overload-resolution off} in order to use an
c906108c
SS
9072explicit function signature to call an overloaded function, as in
9073@smallexample
9074p 'foo(char,int)'('x', 13)
9075@end smallexample
d4f3574e 9076
c906108c 9077The @value{GDBN} command-completion facility can simplify this;
d4f3574e 9078see @ref{Completion, ,Command completion}.
c906108c 9079
c906108c
SS
9080@cindex reference declarations
9081@item
b37052ae
EZ
9082@value{GDBN} understands variables declared as C@t{++} references; you can use
9083them in expressions just as you do in C@t{++} source---they are automatically
c906108c
SS
9084dereferenced.
9085
9086In the parameter list shown when @value{GDBN} displays a frame, the values of
9087reference variables are not displayed (unlike other variables); this
9088avoids clutter, since references are often used for large structures.
9089The @emph{address} of a reference variable is always shown, unless
9090you have specified @samp{set print address off}.
9091
9092@item
b37052ae 9093@value{GDBN} supports the C@t{++} name resolution operator @code{::}---your
c906108c
SS
9094expressions can use it just as expressions in your program do. Since
9095one scope may be defined in another, you can use @code{::} repeatedly if
9096necessary, for example in an expression like
9097@samp{@var{scope1}::@var{scope2}::@var{name}}. @value{GDBN} also allows
b37052ae 9098resolving name scope by reference to source files, in both C and C@t{++}
c906108c
SS
9099debugging (@pxref{Variables, ,Program variables}).
9100@end enumerate
9101
b37052ae 9102In addition, when used with HP's C@t{++} compiler, @value{GDBN} supports
53a5351d
JM
9103calling virtual functions correctly, printing out virtual bases of
9104objects, calling functions in a base subobject, casting objects, and
9105invoking user-defined operators.
c906108c 9106
6d2ebf8b 9107@node C Defaults
b37052ae 9108@subsubsection C and C@t{++} defaults
7a292a7a 9109
b37052ae 9110@cindex C and C@t{++} defaults
c906108c 9111
c906108c
SS
9112If you allow @value{GDBN} to set type and range checking automatically, they
9113both default to @code{off} whenever the working language changes to
b37052ae 9114C or C@t{++}. This happens regardless of whether you or @value{GDBN}
c906108c 9115selects the working language.
c906108c
SS
9116
9117If you allow @value{GDBN} to set the language automatically, it
9118recognizes source files whose names end with @file{.c}, @file{.C}, or
9119@file{.cc}, etc, and when @value{GDBN} enters code compiled from one of
b37052ae 9120these files, it sets the working language to C or C@t{++}.
c906108c
SS
9121@xref{Automatically, ,Having @value{GDBN} infer the source language},
9122for further details.
9123
c906108c
SS
9124@c Type checking is (a) primarily motivated by Modula-2, and (b)
9125@c unimplemented. If (b) changes, it might make sense to let this node
9126@c appear even if Mod-2 does not, but meanwhile ignore it. roland 16jul93.
7a292a7a 9127
6d2ebf8b 9128@node C Checks
b37052ae 9129@subsubsection C and C@t{++} type and range checks
7a292a7a 9130
b37052ae 9131@cindex C and C@t{++} checks
c906108c 9132
b37052ae 9133By default, when @value{GDBN} parses C or C@t{++} expressions, type checking
c906108c
SS
9134is not used. However, if you turn type checking on, @value{GDBN}
9135considers two variables type equivalent if:
9136
9137@itemize @bullet
9138@item
9139The two variables are structured and have the same structure, union, or
9140enumerated tag.
9141
9142@item
9143The two variables have the same type name, or types that have been
9144declared equivalent through @code{typedef}.
9145
9146@ignore
9147@c leaving this out because neither J Gilmore nor R Pesch understand it.
9148@c FIXME--beers?
9149@item
9150The two @code{struct}, @code{union}, or @code{enum} variables are
9151declared in the same declaration. (Note: this may not be true for all C
9152compilers.)
9153@end ignore
9154@end itemize
9155
9156Range checking, if turned on, is done on mathematical operations. Array
9157indices are not checked, since they are often used to index a pointer
9158that is not itself an array.
c906108c 9159
6d2ebf8b 9160@node Debugging C
c906108c 9161@subsubsection @value{GDBN} and C
c906108c
SS
9162
9163The @code{set print union} and @code{show print union} commands apply to
9164the @code{union} type. When set to @samp{on}, any @code{union} that is
7a292a7a
SS
9165inside a @code{struct} or @code{class} is also printed. Otherwise, it
9166appears as @samp{@{...@}}.
c906108c
SS
9167
9168The @code{@@} operator aids in the debugging of dynamic arrays, formed
9169with pointers and a memory allocation function. @xref{Expressions,
9170,Expressions}.
9171
c906108c 9172@menu
5d161b24 9173* Debugging C plus plus::
c906108c
SS
9174@end menu
9175
6d2ebf8b 9176@node Debugging C plus plus
b37052ae 9177@subsubsection @value{GDBN} features for C@t{++}
c906108c 9178
b37052ae 9179@cindex commands for C@t{++}
7a292a7a 9180
b37052ae
EZ
9181Some @value{GDBN} commands are particularly useful with C@t{++}, and some are
9182designed specifically for use with C@t{++}. Here is a summary:
c906108c
SS
9183
9184@table @code
9185@cindex break in overloaded functions
9186@item @r{breakpoint menus}
9187When you want a breakpoint in a function whose name is overloaded,
9188@value{GDBN} breakpoint menus help you specify which function definition
9189you want. @xref{Breakpoint Menus,,Breakpoint menus}.
9190
b37052ae 9191@cindex overloading in C@t{++}
c906108c
SS
9192@item rbreak @var{regex}
9193Setting breakpoints using regular expressions is helpful for setting
9194breakpoints on overloaded functions that are not members of any special
9195classes.
9196@xref{Set Breaks, ,Setting breakpoints}.
9197
b37052ae 9198@cindex C@t{++} exception handling
c906108c
SS
9199@item catch throw
9200@itemx catch catch
b37052ae 9201Debug C@t{++} exception handling using these commands. @xref{Set
c906108c
SS
9202Catchpoints, , Setting catchpoints}.
9203
9204@cindex inheritance
9205@item ptype @var{typename}
9206Print inheritance relationships as well as other information for type
9207@var{typename}.
9208@xref{Symbols, ,Examining the Symbol Table}.
9209
b37052ae 9210@cindex C@t{++} symbol display
c906108c
SS
9211@item set print demangle
9212@itemx show print demangle
9213@itemx set print asm-demangle
9214@itemx show print asm-demangle
b37052ae
EZ
9215Control whether C@t{++} symbols display in their source form, both when
9216displaying code as C@t{++} source and when displaying disassemblies.
c906108c
SS
9217@xref{Print Settings, ,Print settings}.
9218
9219@item set print object
9220@itemx show print object
9221Choose whether to print derived (actual) or declared types of objects.
9222@xref{Print Settings, ,Print settings}.
9223
9224@item set print vtbl
9225@itemx show print vtbl
9226Control the format for printing virtual function tables.
9227@xref{Print Settings, ,Print settings}.
c906108c 9228(The @code{vtbl} commands do not work on programs compiled with the HP
b37052ae 9229ANSI C@t{++} compiler (@code{aCC}).)
c906108c
SS
9230
9231@kindex set overload-resolution
d4f3574e 9232@cindex overloaded functions, overload resolution
c906108c 9233@item set overload-resolution on
b37052ae 9234Enable overload resolution for C@t{++} expression evaluation. The default
c906108c
SS
9235is on. For overloaded functions, @value{GDBN} evaluates the arguments
9236and searches for a function whose signature matches the argument types,
b37052ae 9237using the standard C@t{++} conversion rules (see @ref{C plus plus expressions, ,C@t{++}
d4f3574e 9238expressions}, for details). If it cannot find a match, it emits a
c906108c
SS
9239message.
9240
9241@item set overload-resolution off
b37052ae 9242Disable overload resolution for C@t{++} expression evaluation. For
c906108c
SS
9243overloaded functions that are not class member functions, @value{GDBN}
9244chooses the first function of the specified name that it finds in the
9245symbol table, whether or not its arguments are of the correct type. For
9246overloaded functions that are class member functions, @value{GDBN}
9247searches for a function whose signature @emph{exactly} matches the
9248argument types.
c906108c 9249
9c16f35a
EZ
9250@kindex show overload-resolution
9251@item show overload-resolution
9252Show the current setting of overload resolution.
9253
c906108c
SS
9254@item @r{Overloaded symbol names}
9255You can specify a particular definition of an overloaded symbol, using
b37052ae 9256the same notation that is used to declare such symbols in C@t{++}: type
c906108c
SS
9257@code{@var{symbol}(@var{types})} rather than just @var{symbol}. You can
9258also use the @value{GDBN} command-line word completion facilities to list the
9259available choices, or to finish the type list for you.
9260@xref{Completion,, Command completion}, for details on how to do this.
9261@end table
c906108c 9262
b37303ee
AF
9263@node Objective-C
9264@subsection Objective-C
9265
9266@cindex Objective-C
9267This section provides information about some commands and command
721c2651
EZ
9268options that are useful for debugging Objective-C code. See also
9269@ref{Symbols, info classes}, and @ref{Symbols, info selectors}, for a
9270few more commands specific to Objective-C support.
b37303ee
AF
9271
9272@menu
b383017d
RM
9273* Method Names in Commands::
9274* The Print Command with Objective-C::
b37303ee
AF
9275@end menu
9276
9277@node Method Names in Commands, The Print Command with Objective-C, Objective-C, Objective-C
9278@subsubsection Method Names in Commands
9279
9280The following commands have been extended to accept Objective-C method
9281names as line specifications:
9282
9283@kindex clear@r{, and Objective-C}
9284@kindex break@r{, and Objective-C}
9285@kindex info line@r{, and Objective-C}
9286@kindex jump@r{, and Objective-C}
9287@kindex list@r{, and Objective-C}
9288@itemize
9289@item @code{clear}
9290@item @code{break}
9291@item @code{info line}
9292@item @code{jump}
9293@item @code{list}
9294@end itemize
9295
9296A fully qualified Objective-C method name is specified as
9297
9298@smallexample
9299-[@var{Class} @var{methodName}]
9300@end smallexample
9301
c552b3bb
JM
9302where the minus sign is used to indicate an instance method and a
9303plus sign (not shown) is used to indicate a class method. The class
9304name @var{Class} and method name @var{methodName} are enclosed in
9305brackets, similar to the way messages are specified in Objective-C
9306source code. For example, to set a breakpoint at the @code{create}
9307instance method of class @code{Fruit} in the program currently being
9308debugged, enter:
b37303ee
AF
9309
9310@smallexample
9311break -[Fruit create]
9312@end smallexample
9313
9314To list ten program lines around the @code{initialize} class method,
9315enter:
9316
9317@smallexample
9318list +[NSText initialize]
9319@end smallexample
9320
c552b3bb
JM
9321In the current version of @value{GDBN}, the plus or minus sign is
9322required. In future versions of @value{GDBN}, the plus or minus
9323sign will be optional, but you can use it to narrow the search. It
9324is also possible to specify just a method name:
b37303ee
AF
9325
9326@smallexample
9327break create
9328@end smallexample
9329
9330You must specify the complete method name, including any colons. If
9331your program's source files contain more than one @code{create} method,
9332you'll be presented with a numbered list of classes that implement that
9333method. Indicate your choice by number, or type @samp{0} to exit if
9334none apply.
9335
9336As another example, to clear a breakpoint established at the
9337@code{makeKeyAndOrderFront:} method of the @code{NSWindow} class, enter:
9338
9339@smallexample
9340clear -[NSWindow makeKeyAndOrderFront:]
9341@end smallexample
9342
9343@node The Print Command with Objective-C
9344@subsubsection The Print Command With Objective-C
721c2651 9345@cindex Objective-C, print objects
c552b3bb
JM
9346@kindex print-object
9347@kindex po @r{(@code{print-object})}
b37303ee 9348
c552b3bb 9349The print command has also been extended to accept methods. For example:
b37303ee
AF
9350
9351@smallexample
c552b3bb 9352print -[@var{object} hash]
b37303ee
AF
9353@end smallexample
9354
9355@cindex print an Objective-C object description
c552b3bb
JM
9356@cindex @code{_NSPrintForDebugger}, and printing Objective-C objects
9357@noindent
9358will tell @value{GDBN} to send the @code{hash} message to @var{object}
9359and print the result. Also, an additional command has been added,
9360@code{print-object} or @code{po} for short, which is meant to print
9361the description of an object. However, this command may only work
9362with certain Objective-C libraries that have a particular hook
9363function, @code{_NSPrintForDebugger}, defined.
b37303ee 9364
09d4efe1
EZ
9365@node Fortran
9366@subsection Fortran
9367@cindex Fortran-specific support in @value{GDBN}
9368
814e32d7
WZ
9369@value{GDBN} can be used to debug programs written in Fortran, but it
9370currently supports only the features of Fortran 77 language.
9371
9372@cindex trailing underscore, in Fortran symbols
9373Some Fortran compilers (@sc{gnu} Fortran 77 and Fortran 95 compilers
9374among them) append an underscore to the names of variables and
9375functions. When you debug programs compiled by those compilers, you
9376will need to refer to variables and functions with a trailing
9377underscore.
9378
9379@menu
9380* Fortran Operators:: Fortran operators and expressions
9381* Fortran Defaults:: Default settings for Fortran
9382* Special Fortran commands:: Special @value{GDBN} commands for Fortran
9383@end menu
9384
9385@node Fortran Operators
9386@subsubsection Fortran operators and expressions
9387
9388@cindex Fortran operators and expressions
9389
9390Operators must be defined on values of specific types. For instance,
9391@code{+} is defined on numbers, but not on characters or other non-
ff2587ec 9392arithmetic types. Operators are often defined on groups of types.
814e32d7
WZ
9393
9394@table @code
9395@item **
9396The exponentiation operator. It raises the first operand to the power
9397of the second one.
9398
9399@item :
9400The range operator. Normally used in the form of array(low:high) to
9401represent a section of array.
9402@end table
9403
9404@node Fortran Defaults
9405@subsubsection Fortran Defaults
9406
9407@cindex Fortran Defaults
9408
9409Fortran symbols are usually case-insensitive, so @value{GDBN} by
9410default uses case-insensitive matches for Fortran symbols. You can
9411change that with the @samp{set case-insensitive} command, see
9412@ref{Symbols}, for the details.
9413
9414@node Special Fortran commands
9415@subsubsection Special Fortran commands
9416
9417@cindex Special Fortran commands
9418
9419@value{GDBN} had some commands to support Fortran specific feature,
9420such as common block displaying.
9421
09d4efe1
EZ
9422@table @code
9423@cindex @code{COMMON} blocks, Fortran
9424@kindex info common
9425@item info common @r{[}@var{common-name}@r{]}
9426This command prints the values contained in the Fortran @code{COMMON}
9427block whose name is @var{common-name}. With no argument, the names of
9428all @code{COMMON} blocks visible at current program location are
9429printed.
9430@end table
9431
9c16f35a
EZ
9432@node Pascal
9433@subsection Pascal
9434
9435@cindex Pascal support in @value{GDBN}, limitations
9436Debugging Pascal programs which use sets, subranges, file variables, or
9437nested functions does not currently work. @value{GDBN} does not support
9438entering expressions, printing values, or similar features using Pascal
9439syntax.
9440
9441The Pascal-specific command @code{set print pascal_static-members}
9442controls whether static members of Pascal objects are displayed.
9443@xref{Print Settings, pascal_static-members}.
9444
09d4efe1 9445@node Modula-2
c906108c 9446@subsection Modula-2
7a292a7a 9447
d4f3574e 9448@cindex Modula-2, @value{GDBN} support
c906108c
SS
9449
9450The extensions made to @value{GDBN} to support Modula-2 only support
9451output from the @sc{gnu} Modula-2 compiler (which is currently being
9452developed). Other Modula-2 compilers are not currently supported, and
9453attempting to debug executables produced by them is most likely
9454to give an error as @value{GDBN} reads in the executable's symbol
9455table.
9456
9457@cindex expressions in Modula-2
9458@menu
9459* M2 Operators:: Built-in operators
9460* Built-In Func/Proc:: Built-in functions and procedures
9461* M2 Constants:: Modula-2 constants
9462* M2 Defaults:: Default settings for Modula-2
9463* Deviations:: Deviations from standard Modula-2
9464* M2 Checks:: Modula-2 type and range checks
9465* M2 Scope:: The scope operators @code{::} and @code{.}
9466* GDB/M2:: @value{GDBN} and Modula-2
9467@end menu
9468
6d2ebf8b 9469@node M2 Operators
c906108c
SS
9470@subsubsection Operators
9471@cindex Modula-2 operators
9472
9473Operators must be defined on values of specific types. For instance,
9474@code{+} is defined on numbers, but not on structures. Operators are
9475often defined on groups of types. For the purposes of Modula-2, the
9476following definitions hold:
9477
9478@itemize @bullet
9479
9480@item
9481@emph{Integral types} consist of @code{INTEGER}, @code{CARDINAL}, and
9482their subranges.
9483
9484@item
9485@emph{Character types} consist of @code{CHAR} and its subranges.
9486
9487@item
9488@emph{Floating-point types} consist of @code{REAL}.
9489
9490@item
9491@emph{Pointer types} consist of anything declared as @code{POINTER TO
9492@var{type}}.
9493
9494@item
9495@emph{Scalar types} consist of all of the above.
9496
9497@item
9498@emph{Set types} consist of @code{SET} and @code{BITSET} types.
9499
9500@item
9501@emph{Boolean types} consist of @code{BOOLEAN}.
9502@end itemize
9503
9504@noindent
9505The following operators are supported, and appear in order of
9506increasing precedence:
9507
9508@table @code
9509@item ,
9510Function argument or array index separator.
9511
9512@item :=
9513Assignment. The value of @var{var} @code{:=} @var{value} is
9514@var{value}.
9515
9516@item <@r{, }>
9517Less than, greater than on integral, floating-point, or enumerated
9518types.
9519
9520@item <=@r{, }>=
96a2c332 9521Less than or equal to, greater than or equal to
c906108c
SS
9522on integral, floating-point and enumerated types, or set inclusion on
9523set types. Same precedence as @code{<}.
9524
9525@item =@r{, }<>@r{, }#
9526Equality and two ways of expressing inequality, valid on scalar types.
9527Same precedence as @code{<}. In @value{GDBN} scripts, only @code{<>} is
9528available for inequality, since @code{#} conflicts with the script
9529comment character.
9530
9531@item IN
9532Set membership. Defined on set types and the types of their members.
9533Same precedence as @code{<}.
9534
9535@item OR
9536Boolean disjunction. Defined on boolean types.
9537
9538@item AND@r{, }&
d4f3574e 9539Boolean conjunction. Defined on boolean types.
c906108c
SS
9540
9541@item @@
9542The @value{GDBN} ``artificial array'' operator (@pxref{Expressions, ,Expressions}).
9543
9544@item +@r{, }-
9545Addition and subtraction on integral and floating-point types, or union
9546and difference on set types.
9547
9548@item *
9549Multiplication on integral and floating-point types, or set intersection
9550on set types.
9551
9552@item /
9553Division on floating-point types, or symmetric set difference on set
9554types. Same precedence as @code{*}.
9555
9556@item DIV@r{, }MOD
9557Integer division and remainder. Defined on integral types. Same
9558precedence as @code{*}.
9559
9560@item -
9561Negative. Defined on @code{INTEGER} and @code{REAL} data.
9562
9563@item ^
9564Pointer dereferencing. Defined on pointer types.
9565
9566@item NOT
9567Boolean negation. Defined on boolean types. Same precedence as
9568@code{^}.
9569
9570@item .
9571@code{RECORD} field selector. Defined on @code{RECORD} data. Same
9572precedence as @code{^}.
9573
9574@item []
9575Array indexing. Defined on @code{ARRAY} data. Same precedence as @code{^}.
9576
9577@item ()
9578Procedure argument list. Defined on @code{PROCEDURE} objects. Same precedence
9579as @code{^}.
9580
9581@item ::@r{, }.
9582@value{GDBN} and Modula-2 scope operators.
9583@end table
9584
9585@quotation
9586@emph{Warning:} Sets and their operations are not yet supported, so @value{GDBN}
9587treats the use of the operator @code{IN}, or the use of operators
9588@code{+}, @code{-}, @code{*}, @code{/}, @code{=}, , @code{<>}, @code{#},
9589@code{<=}, and @code{>=} on sets as an error.
9590@end quotation
9591
cb51c4e0 9592
6d2ebf8b 9593@node Built-In Func/Proc
c906108c 9594@subsubsection Built-in functions and procedures
cb51c4e0 9595@cindex Modula-2 built-ins
c906108c
SS
9596
9597Modula-2 also makes available several built-in procedures and functions.
9598In describing these, the following metavariables are used:
9599
9600@table @var
9601
9602@item a
9603represents an @code{ARRAY} variable.
9604
9605@item c
9606represents a @code{CHAR} constant or variable.
9607
9608@item i
9609represents a variable or constant of integral type.
9610
9611@item m
9612represents an identifier that belongs to a set. Generally used in the
9613same function with the metavariable @var{s}. The type of @var{s} should
9614be @code{SET OF @var{mtype}} (where @var{mtype} is the type of @var{m}).
9615
9616@item n
9617represents a variable or constant of integral or floating-point type.
9618
9619@item r
9620represents a variable or constant of floating-point type.
9621
9622@item t
9623represents a type.
9624
9625@item v
9626represents a variable.
9627
9628@item x
9629represents a variable or constant of one of many types. See the
9630explanation of the function for details.
9631@end table
9632
9633All Modula-2 built-in procedures also return a result, described below.
9634
9635@table @code
9636@item ABS(@var{n})
9637Returns the absolute value of @var{n}.
9638
9639@item CAP(@var{c})
9640If @var{c} is a lower case letter, it returns its upper case
c3f6f71d 9641equivalent, otherwise it returns its argument.
c906108c
SS
9642
9643@item CHR(@var{i})
9644Returns the character whose ordinal value is @var{i}.
9645
9646@item DEC(@var{v})
c3f6f71d 9647Decrements the value in the variable @var{v} by one. Returns the new value.
c906108c
SS
9648
9649@item DEC(@var{v},@var{i})
9650Decrements the value in the variable @var{v} by @var{i}. Returns the
9651new value.
9652
9653@item EXCL(@var{m},@var{s})
9654Removes the element @var{m} from the set @var{s}. Returns the new
9655set.
9656
9657@item FLOAT(@var{i})
9658Returns the floating point equivalent of the integer @var{i}.
9659
9660@item HIGH(@var{a})
9661Returns the index of the last member of @var{a}.
9662
9663@item INC(@var{v})
c3f6f71d 9664Increments the value in the variable @var{v} by one. Returns the new value.
c906108c
SS
9665
9666@item INC(@var{v},@var{i})
9667Increments the value in the variable @var{v} by @var{i}. Returns the
9668new value.
9669
9670@item INCL(@var{m},@var{s})
9671Adds the element @var{m} to the set @var{s} if it is not already
9672there. Returns the new set.
9673
9674@item MAX(@var{t})
9675Returns the maximum value of the type @var{t}.
9676
9677@item MIN(@var{t})
9678Returns the minimum value of the type @var{t}.
9679
9680@item ODD(@var{i})
9681Returns boolean TRUE if @var{i} is an odd number.
9682
9683@item ORD(@var{x})
9684Returns the ordinal value of its argument. For example, the ordinal
c3f6f71d
JM
9685value of a character is its @sc{ascii} value (on machines supporting the
9686@sc{ascii} character set). @var{x} must be of an ordered type, which include
c906108c
SS
9687integral, character and enumerated types.
9688
9689@item SIZE(@var{x})
9690Returns the size of its argument. @var{x} can be a variable or a type.
9691
9692@item TRUNC(@var{r})
9693Returns the integral part of @var{r}.
9694
9695@item VAL(@var{t},@var{i})
9696Returns the member of the type @var{t} whose ordinal value is @var{i}.
9697@end table
9698
9699@quotation
9700@emph{Warning:} Sets and their operations are not yet supported, so
9701@value{GDBN} treats the use of procedures @code{INCL} and @code{EXCL} as
9702an error.
9703@end quotation
9704
9705@cindex Modula-2 constants
6d2ebf8b 9706@node M2 Constants
c906108c
SS
9707@subsubsection Constants
9708
9709@value{GDBN} allows you to express the constants of Modula-2 in the following
9710ways:
9711
9712@itemize @bullet
9713
9714@item
9715Integer constants are simply a sequence of digits. When used in an
9716expression, a constant is interpreted to be type-compatible with the
9717rest of the expression. Hexadecimal integers are specified by a
9718trailing @samp{H}, and octal integers by a trailing @samp{B}.
9719
9720@item
9721Floating point constants appear as a sequence of digits, followed by a
9722decimal point and another sequence of digits. An optional exponent can
9723then be specified, in the form @samp{E@r{[}+@r{|}-@r{]}@var{nnn}}, where
9724@samp{@r{[}+@r{|}-@r{]}@var{nnn}} is the desired exponent. All of the
9725digits of the floating point constant must be valid decimal (base 10)
9726digits.
9727
9728@item
9729Character constants consist of a single character enclosed by a pair of
9730like quotes, either single (@code{'}) or double (@code{"}). They may
c3f6f71d 9731also be expressed by their ordinal value (their @sc{ascii} value, usually)
c906108c
SS
9732followed by a @samp{C}.
9733
9734@item
9735String constants consist of a sequence of characters enclosed by a
9736pair of like quotes, either single (@code{'}) or double (@code{"}).
9737Escape sequences in the style of C are also allowed. @xref{C
b37052ae 9738Constants, ,C and C@t{++} constants}, for a brief explanation of escape
c906108c
SS
9739sequences.
9740
9741@item
9742Enumerated constants consist of an enumerated identifier.
9743
9744@item
9745Boolean constants consist of the identifiers @code{TRUE} and
9746@code{FALSE}.
9747
9748@item
9749Pointer constants consist of integral values only.
9750
9751@item
9752Set constants are not yet supported.
9753@end itemize
9754
6d2ebf8b 9755@node M2 Defaults
c906108c
SS
9756@subsubsection Modula-2 defaults
9757@cindex Modula-2 defaults
9758
9759If type and range checking are set automatically by @value{GDBN}, they
9760both default to @code{on} whenever the working language changes to
d4f3574e 9761Modula-2. This happens regardless of whether you or @value{GDBN}
c906108c
SS
9762selected the working language.
9763
9764If you allow @value{GDBN} to set the language automatically, then entering
9765code compiled from a file whose name ends with @file{.mod} sets the
d4f3574e 9766working language to Modula-2. @xref{Automatically, ,Having @value{GDBN} set
c906108c
SS
9767the language automatically}, for further details.
9768
6d2ebf8b 9769@node Deviations
c906108c
SS
9770@subsubsection Deviations from standard Modula-2
9771@cindex Modula-2, deviations from
9772
9773A few changes have been made to make Modula-2 programs easier to debug.
9774This is done primarily via loosening its type strictness:
9775
9776@itemize @bullet
9777@item
9778Unlike in standard Modula-2, pointer constants can be formed by
9779integers. This allows you to modify pointer variables during
9780debugging. (In standard Modula-2, the actual address contained in a
9781pointer variable is hidden from you; it can only be modified
9782through direct assignment to another pointer variable or expression that
9783returned a pointer.)
9784
9785@item
9786C escape sequences can be used in strings and characters to represent
9787non-printable characters. @value{GDBN} prints out strings with these
9788escape sequences embedded. Single non-printable characters are
9789printed using the @samp{CHR(@var{nnn})} format.
9790
9791@item
9792The assignment operator (@code{:=}) returns the value of its right-hand
9793argument.
9794
9795@item
9796All built-in procedures both modify @emph{and} return their argument.
9797@end itemize
9798
6d2ebf8b 9799@node M2 Checks
c906108c
SS
9800@subsubsection Modula-2 type and range checks
9801@cindex Modula-2 checks
9802
9803@quotation
9804@emph{Warning:} in this release, @value{GDBN} does not yet perform type or
9805range checking.
9806@end quotation
9807@c FIXME remove warning when type/range checks added
9808
9809@value{GDBN} considers two Modula-2 variables type equivalent if:
9810
9811@itemize @bullet
9812@item
9813They are of types that have been declared equivalent via a @code{TYPE
9814@var{t1} = @var{t2}} statement
9815
9816@item
9817They have been declared on the same line. (Note: This is true of the
9818@sc{gnu} Modula-2 compiler, but it may not be true of other compilers.)
9819@end itemize
9820
9821As long as type checking is enabled, any attempt to combine variables
9822whose types are not equivalent is an error.
9823
9824Range checking is done on all mathematical operations, assignment, array
9825index bounds, and all built-in functions and procedures.
9826
6d2ebf8b 9827@node M2 Scope
c906108c
SS
9828@subsubsection The scope operators @code{::} and @code{.}
9829@cindex scope
41afff9a 9830@cindex @code{.}, Modula-2 scope operator
c906108c
SS
9831@cindex colon, doubled as scope operator
9832@ifinfo
41afff9a 9833@vindex colon-colon@r{, in Modula-2}
c906108c
SS
9834@c Info cannot handle :: but TeX can.
9835@end ifinfo
9836@iftex
41afff9a 9837@vindex ::@r{, in Modula-2}
c906108c
SS
9838@end iftex
9839
9840There are a few subtle differences between the Modula-2 scope operator
9841(@code{.}) and the @value{GDBN} scope operator (@code{::}). The two have
9842similar syntax:
9843
474c8240 9844@smallexample
c906108c
SS
9845
9846@var{module} . @var{id}
9847@var{scope} :: @var{id}
474c8240 9848@end smallexample
c906108c
SS
9849
9850@noindent
9851where @var{scope} is the name of a module or a procedure,
9852@var{module} the name of a module, and @var{id} is any declared
9853identifier within your program, except another module.
9854
9855Using the @code{::} operator makes @value{GDBN} search the scope
9856specified by @var{scope} for the identifier @var{id}. If it is not
9857found in the specified scope, then @value{GDBN} searches all scopes
9858enclosing the one specified by @var{scope}.
9859
9860Using the @code{.} operator makes @value{GDBN} search the current scope for
9861the identifier specified by @var{id} that was imported from the
9862definition module specified by @var{module}. With this operator, it is
9863an error if the identifier @var{id} was not imported from definition
9864module @var{module}, or if @var{id} is not an identifier in
9865@var{module}.
9866
6d2ebf8b 9867@node GDB/M2
c906108c
SS
9868@subsubsection @value{GDBN} and Modula-2
9869
9870Some @value{GDBN} commands have little use when debugging Modula-2 programs.
9871Five subcommands of @code{set print} and @code{show print} apply
b37052ae 9872specifically to C and C@t{++}: @samp{vtbl}, @samp{demangle},
c906108c 9873@samp{asm-demangle}, @samp{object}, and @samp{union}. The first four
b37052ae 9874apply to C@t{++}, and the last to the C @code{union} type, which has no direct
c906108c
SS
9875analogue in Modula-2.
9876
9877The @code{@@} operator (@pxref{Expressions, ,Expressions}), while available
d4f3574e 9878with any language, is not useful with Modula-2. Its
c906108c 9879intent is to aid the debugging of @dfn{dynamic arrays}, which cannot be
b37052ae 9880created in Modula-2 as they can in C or C@t{++}. However, because an
c906108c 9881address can be specified by an integral constant, the construct
d4f3574e 9882@samp{@{@var{type}@}@var{adrexp}} is still useful.
c906108c
SS
9883
9884@cindex @code{#} in Modula-2
9885In @value{GDBN} scripts, the Modula-2 inequality operator @code{#} is
9886interpreted as the beginning of a comment. Use @code{<>} instead.
c906108c 9887
e07c999f
PH
9888@node Ada
9889@subsection Ada
9890@cindex Ada
9891
9892The extensions made to @value{GDBN} for Ada only support
9893output from the @sc{gnu} Ada (GNAT) compiler.
9894Other Ada compilers are not currently supported, and
9895attempting to debug executables produced by them is most likely
9896to be difficult.
9897
9898
9899@cindex expressions in Ada
9900@menu
9901* Ada Mode Intro:: General remarks on the Ada syntax
9902 and semantics supported by Ada mode
9903 in @value{GDBN}.
9904* Omissions from Ada:: Restrictions on the Ada expression syntax.
9905* Additions to Ada:: Extensions of the Ada expression syntax.
9906* Stopping Before Main Program:: Debugging the program during elaboration.
9907* Ada Glitches:: Known peculiarities of Ada mode.
9908@end menu
9909
9910@node Ada Mode Intro
9911@subsubsection Introduction
9912@cindex Ada mode, general
9913
9914The Ada mode of @value{GDBN} supports a fairly large subset of Ada expression
9915syntax, with some extensions.
9916The philosophy behind the design of this subset is
9917
9918@itemize @bullet
9919@item
9920That @value{GDBN} should provide basic literals and access to operations for
9921arithmetic, dereferencing, field selection, indexing, and subprogram calls,
9922leaving more sophisticated computations to subprograms written into the
9923program (which therefore may be called from @value{GDBN}).
9924
9925@item
9926That type safety and strict adherence to Ada language restrictions
9927are not particularly important to the @value{GDBN} user.
9928
9929@item
9930That brevity is important to the @value{GDBN} user.
9931@end itemize
9932
9933Thus, for brevity, the debugger acts as if there were
9934implicit @code{with} and @code{use} clauses in effect for all user-written
9935packages, making it unnecessary to fully qualify most names with
9936their packages, regardless of context. Where this causes ambiguity,
9937@value{GDBN} asks the user's intent.
9938
9939The debugger will start in Ada mode if it detects an Ada main program.
9940As for other languages, it will enter Ada mode when stopped in a program that
9941was translated from an Ada source file.
9942
9943While in Ada mode, you may use `@t{--}' for comments. This is useful
9944mostly for documenting command files. The standard @value{GDBN} comment
9945(@samp{#}) still works at the beginning of a line in Ada mode, but not in the
9946middle (to allow based literals).
9947
9948The debugger supports limited overloading. Given a subprogram call in which
9949the function symbol has multiple definitions, it will use the number of
9950actual parameters and some information about their types to attempt to narrow
9951the set of definitions. It also makes very limited use of context, preferring
9952procedures to functions in the context of the @code{call} command, and
9953functions to procedures elsewhere.
9954
9955@node Omissions from Ada
9956@subsubsection Omissions from Ada
9957@cindex Ada, omissions from
9958
9959Here are the notable omissions from the subset:
9960
9961@itemize @bullet
9962@item
9963Only a subset of the attributes are supported:
9964
9965@itemize @minus
9966@item
9967@t{'First}, @t{'Last}, and @t{'Length}
9968 on array objects (not on types and subtypes).
9969
9970@item
9971@t{'Min} and @t{'Max}.
9972
9973@item
9974@t{'Pos} and @t{'Val}.
9975
9976@item
9977@t{'Tag}.
9978
9979@item
9980@t{'Range} on array objects (not subtypes), but only as the right
9981operand of the membership (@code{in}) operator.
9982
9983@item
9984@t{'Access}, @t{'Unchecked_Access}, and
9985@t{'Unrestricted_Access} (a GNAT extension).
9986
9987@item
9988@t{'Address}.
9989@end itemize
9990
9991@item
9992The names in
9993@code{Characters.Latin_1} are not available and
9994concatenation is not implemented. Thus, escape characters in strings are
9995not currently available.
9996
9997@item
9998Equality tests (@samp{=} and @samp{/=}) on arrays test for bitwise
9999equality of representations. They will generally work correctly
10000for strings and arrays whose elements have integer or enumeration types.
10001They may not work correctly for arrays whose element
10002types have user-defined equality, for arrays of real values
10003(in particular, IEEE-conformant floating point, because of negative
10004zeroes and NaNs), and for arrays whose elements contain unused bits with
10005indeterminate values.
10006
10007@item
10008The other component-by-component array operations (@code{and}, @code{or},
10009@code{xor}, @code{not}, and relational tests other than equality)
10010are not implemented.
10011
10012@item
860701dc
PH
10013@cindex array aggregates (Ada)
10014@cindex record aggregates (Ada)
10015@cindex aggregates (Ada)
10016There is limited support for array and record aggregates. They are
10017permitted only on the right sides of assignments, as in these examples:
10018
10019@smallexample
10020set An_Array := (1, 2, 3, 4, 5, 6)
10021set An_Array := (1, others => 0)
10022set An_Array := (0|4 => 1, 1..3 => 2, 5 => 6)
10023set A_2D_Array := ((1, 2, 3), (4, 5, 6), (7, 8, 9))
10024set A_Record := (1, "Peter", True);
10025set A_Record := (Name => "Peter", Id => 1, Alive => True)
10026@end smallexample
10027
10028Changing a
10029discriminant's value by assigning an aggregate has an
10030undefined effect if that discriminant is used within the record.
10031However, you can first modify discriminants by directly assigning to
10032them (which normally would not be allowed in Ada), and then performing an
10033aggregate assignment. For example, given a variable @code{A_Rec}
10034declared to have a type such as:
10035
10036@smallexample
10037type Rec (Len : Small_Integer := 0) is record
10038 Id : Integer;
10039 Vals : IntArray (1 .. Len);
10040end record;
10041@end smallexample
10042
10043you can assign a value with a different size of @code{Vals} with two
10044assignments:
10045
10046@smallexample
10047set A_Rec.Len := 4
10048set A_Rec := (Id => 42, Vals => (1, 2, 3, 4))
10049@end smallexample
10050
10051As this example also illustrates, @value{GDBN} is very loose about the usual
10052rules concerning aggregates. You may leave out some of the
10053components of an array or record aggregate (such as the @code{Len}
10054component in the assignment to @code{A_Rec} above); they will retain their
10055original values upon assignment. You may freely use dynamic values as
10056indices in component associations. You may even use overlapping or
10057redundant component associations, although which component values are
10058assigned in such cases is not defined.
e07c999f
PH
10059
10060@item
10061Calls to dispatching subprograms are not implemented.
10062
10063@item
10064The overloading algorithm is much more limited (i.e., less selective)
10065than that of real Ada. It makes only limited use of the context in which a subexpression
10066appears to resolve its meaning, and it is much looser in its rules for allowing
10067type matches. As a result, some function calls will be ambiguous, and the user
10068will be asked to choose the proper resolution.
10069
10070@item
10071The @code{new} operator is not implemented.
10072
10073@item
10074Entry calls are not implemented.
10075
10076@item
10077Aside from printing, arithmetic operations on the native VAX floating-point
10078formats are not supported.
10079
10080@item
10081It is not possible to slice a packed array.
10082@end itemize
10083
10084@node Additions to Ada
10085@subsubsection Additions to Ada
10086@cindex Ada, deviations from
10087
10088As it does for other languages, @value{GDBN} makes certain generic
10089extensions to Ada (@pxref{Expressions}):
10090
10091@itemize @bullet
10092@item
10093If the expression @var{E} is a variable residing in memory
10094(typically a local variable or array element) and @var{N} is
10095a positive integer, then @code{@var{E}@@@var{N}} displays the values of
10096@var{E} and the @var{N}-1 adjacent variables following it in memory as an array.
10097In Ada, this operator is generally not necessary, since its prime use
10098is in displaying parts of an array, and slicing will usually do this in Ada.
10099However, there are occasional uses when debugging programs
10100in which certain debugging information has been optimized away.
10101
10102@item
10103@code{@var{B}::@var{var}} means ``the variable named @var{var} that appears
10104in function or file @var{B}.'' When @var{B} is a file name, you must typically
10105surround it in single quotes.
10106
10107@item
10108The expression @code{@{@var{type}@} @var{addr}} means ``the variable of type
10109@var{type} that appears at address @var{addr}.''
10110
10111@item
10112A name starting with @samp{$} is a convenience variable
10113(@pxref{Convenience Vars}) or a machine register (@pxref{Registers}).
10114@end itemize
10115
10116In addition, @value{GDBN} provides a few other shortcuts and outright additions specific
10117to Ada:
10118
10119@itemize @bullet
10120@item
10121The assignment statement is allowed as an expression, returning
10122its right-hand operand as its value. Thus, you may enter
10123
10124@smallexample
10125set x := y + 3
10126print A(tmp := y + 1)
10127@end smallexample
10128
10129@item
10130The semicolon is allowed as an ``operator,'' returning as its value
10131the value of its right-hand operand.
10132This allows, for example,
10133complex conditional breaks:
10134
10135@smallexample
10136break f
10137condition 1 (report(i); k += 1; A(k) > 100)
10138@end smallexample
10139
10140@item
10141Rather than use catenation and symbolic character names to introduce special
10142characters into strings, one may instead use a special bracket notation,
10143which is also used to print strings. A sequence of characters of the form
10144@samp{["@var{XX}"]} within a string or character literal denotes the
10145(single) character whose numeric encoding is @var{XX} in hexadecimal. The
10146sequence of characters @samp{["""]} also denotes a single quotation mark
10147in strings. For example,
10148@smallexample
10149 "One line.["0a"]Next line.["0a"]"
10150@end smallexample
10151@noindent
10152contains an ASCII newline character (@code{Ada.Characters.Latin_1.LF}) after each
10153period.
10154
10155@item
10156The subtype used as a prefix for the attributes @t{'Pos}, @t{'Min}, and
10157@t{'Max} is optional (and is ignored in any case). For example, it is valid
10158to write
10159
10160@smallexample
10161print 'max(x, y)
10162@end smallexample
10163
10164@item
10165When printing arrays, @value{GDBN} uses positional notation when the
10166array has a lower bound of 1, and uses a modified named notation otherwise.
10167For example, a one-dimensional array of three integers with a lower bound of 3 might print as
10168
10169@smallexample
10170(3 => 10, 17, 1)
10171@end smallexample
10172
10173@noindent
10174That is, in contrast to valid Ada, only the first component has a @code{=>}
10175clause.
10176
10177@item
10178You may abbreviate attributes in expressions with any unique,
10179multi-character subsequence of
10180their names (an exact match gets preference).
10181For example, you may use @t{a'len}, @t{a'gth}, or @t{a'lh}
10182in place of @t{a'length}.
10183
10184@item
10185@cindex quoting Ada internal identifiers
10186Since Ada is case-insensitive, the debugger normally maps identifiers you type
10187to lower case. The GNAT compiler uses upper-case characters for
10188some of its internal identifiers, which are normally of no interest to users.
10189For the rare occasions when you actually have to look at them,
10190enclose them in angle brackets to avoid the lower-case mapping.
10191For example,
10192@smallexample
10193@value{GDBP} print <JMPBUF_SAVE>[0]
10194@end smallexample
10195
10196@item
10197Printing an object of class-wide type or dereferencing an
10198access-to-class-wide value will display all the components of the object's
10199specific type (as indicated by its run-time tag). Likewise, component
10200selection on such a value will operate on the specific type of the
10201object.
10202
10203@end itemize
10204
10205@node Stopping Before Main Program
10206@subsubsection Stopping at the Very Beginning
10207
10208@cindex breakpointing Ada elaboration code
10209It is sometimes necessary to debug the program during elaboration, and
10210before reaching the main procedure.
10211As defined in the Ada Reference
10212Manual, the elaboration code is invoked from a procedure called
10213@code{adainit}. To run your program up to the beginning of
10214elaboration, simply use the following two commands:
10215@code{tbreak adainit} and @code{run}.
10216
10217@node Ada Glitches
10218@subsubsection Known Peculiarities of Ada Mode
10219@cindex Ada, problems
10220
10221Besides the omissions listed previously (@pxref{Omissions from Ada}),
10222we know of several problems with and limitations of Ada mode in
10223@value{GDBN},
10224some of which will be fixed with planned future releases of the debugger
10225and the GNU Ada compiler.
10226
10227@itemize @bullet
10228@item
10229Currently, the debugger
10230has insufficient information to determine whether certain pointers represent
10231pointers to objects or the objects themselves.
10232Thus, the user may have to tack an extra @code{.all} after an expression
10233to get it printed properly.
10234
10235@item
10236Static constants that the compiler chooses not to materialize as objects in
10237storage are invisible to the debugger.
10238
10239@item
10240Named parameter associations in function argument lists are ignored (the
10241argument lists are treated as positional).
10242
10243@item
10244Many useful library packages are currently invisible to the debugger.
10245
10246@item
10247Fixed-point arithmetic, conversions, input, and output is carried out using
10248floating-point arithmetic, and may give results that only approximate those on
10249the host machine.
10250
10251@item
10252The type of the @t{'Address} attribute may not be @code{System.Address}.
10253
10254@item
10255The GNAT compiler never generates the prefix @code{Standard} for any of
10256the standard symbols defined by the Ada language. @value{GDBN} knows about
10257this: it will strip the prefix from names when you use it, and will never
10258look for a name you have so qualified among local symbols, nor match against
10259symbols in other packages or subprograms. If you have
10260defined entities anywhere in your program other than parameters and
10261local variables whose simple names match names in @code{Standard},
10262GNAT's lack of qualification here can cause confusion. When this happens,
10263you can usually resolve the confusion
10264by qualifying the problematic names with package
10265@code{Standard} explicitly.
10266@end itemize
10267
4e562065
JB
10268@node Unsupported languages
10269@section Unsupported languages
10270
10271@cindex unsupported languages
10272@cindex minimal language
10273In addition to the other fully-supported programming languages,
10274@value{GDBN} also provides a pseudo-language, called @code{minimal}.
10275It does not represent a real programming language, but provides a set
10276of capabilities close to what the C or assembly languages provide.
10277This should allow most simple operations to be performed while debugging
10278an application that uses a language currently not supported by @value{GDBN}.
10279
10280If the language is set to @code{auto}, @value{GDBN} will automatically
10281select this language if the current frame corresponds to an unsupported
10282language.
10283
6d2ebf8b 10284@node Symbols
c906108c
SS
10285@chapter Examining the Symbol Table
10286
d4f3574e 10287The commands described in this chapter allow you to inquire about the
c906108c
SS
10288symbols (names of variables, functions and types) defined in your
10289program. This information is inherent in the text of your program and
10290does not change as your program executes. @value{GDBN} finds it in your
10291program's symbol table, in the file indicated when you started @value{GDBN}
10292(@pxref{File Options, ,Choosing files}), or by one of the
10293file-management commands (@pxref{Files, ,Commands to specify files}).
10294
10295@cindex symbol names
10296@cindex names of symbols
10297@cindex quoting names
10298Occasionally, you may need to refer to symbols that contain unusual
10299characters, which @value{GDBN} ordinarily treats as word delimiters. The
10300most frequent case is in referring to static variables in other
10301source files (@pxref{Variables,,Program variables}). File names
10302are recorded in object files as debugging symbols, but @value{GDBN} would
10303ordinarily parse a typical file name, like @file{foo.c}, as the three words
10304@samp{foo} @samp{.} @samp{c}. To allow @value{GDBN} to recognize
10305@samp{foo.c} as a single symbol, enclose it in single quotes; for example,
10306
474c8240 10307@smallexample
c906108c 10308p 'foo.c'::x
474c8240 10309@end smallexample
c906108c
SS
10310
10311@noindent
10312looks up the value of @code{x} in the scope of the file @file{foo.c}.
10313
10314@table @code
a8f24a35
EZ
10315@cindex case-insensitive symbol names
10316@cindex case sensitivity in symbol names
10317@kindex set case-sensitive
10318@item set case-sensitive on
10319@itemx set case-sensitive off
10320@itemx set case-sensitive auto
10321Normally, when @value{GDBN} looks up symbols, it matches their names
10322with case sensitivity determined by the current source language.
10323Occasionally, you may wish to control that. The command @code{set
10324case-sensitive} lets you do that by specifying @code{on} for
10325case-sensitive matches or @code{off} for case-insensitive ones. If
10326you specify @code{auto}, case sensitivity is reset to the default
10327suitable for the source language. The default is case-sensitive
10328matches for all languages except for Fortran, for which the default is
10329case-insensitive matches.
10330
9c16f35a
EZ
10331@kindex show case-sensitive
10332@item show case-sensitive
a8f24a35
EZ
10333This command shows the current setting of case sensitivity for symbols
10334lookups.
10335
c906108c 10336@kindex info address
b37052ae 10337@cindex address of a symbol
c906108c
SS
10338@item info address @var{symbol}
10339Describe where the data for @var{symbol} is stored. For a register
10340variable, this says which register it is kept in. For a non-register
10341local variable, this prints the stack-frame offset at which the variable
10342is always stored.
10343
10344Note the contrast with @samp{print &@var{symbol}}, which does not work
10345at all for a register variable, and for a stack local variable prints
10346the exact address of the current instantiation of the variable.
10347
3d67e040 10348@kindex info symbol
b37052ae 10349@cindex symbol from address
9c16f35a 10350@cindex closest symbol and offset for an address
3d67e040
EZ
10351@item info symbol @var{addr}
10352Print the name of a symbol which is stored at the address @var{addr}.
10353If no symbol is stored exactly at @var{addr}, @value{GDBN} prints the
10354nearest symbol and an offset from it:
10355
474c8240 10356@smallexample
3d67e040
EZ
10357(@value{GDBP}) info symbol 0x54320
10358_initialize_vx + 396 in section .text
474c8240 10359@end smallexample
3d67e040
EZ
10360
10361@noindent
10362This is the opposite of the @code{info address} command. You can use
10363it to find out the name of a variable or a function given its address.
10364
c906108c 10365@kindex whatis
62f3a2ba
FF
10366@item whatis [@var{arg}]
10367Print the data type of @var{arg}, which can be either an expression or
10368a data type. With no argument, print the data type of @code{$}, the
10369last value in the value history. If @var{arg} is an expression, it is
10370not actually evaluated, and any side-effecting operations (such as
10371assignments or function calls) inside it do not take place. If
10372@var{arg} is a type name, it may be the name of a type or typedef, or
10373for C code it may have the form @samp{class @var{class-name}},
10374@samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or
10375@samp{enum @var{enum-tag}}.
c906108c
SS
10376@xref{Expressions, ,Expressions}.
10377
c906108c 10378@kindex ptype
62f3a2ba
FF
10379@item ptype [@var{arg}]
10380@code{ptype} accepts the same arguments as @code{whatis}, but prints a
10381detailed description of the type, instead of just the name of the type.
10382@xref{Expressions, ,Expressions}.
c906108c
SS
10383
10384For example, for this variable declaration:
10385
474c8240 10386@smallexample
c906108c 10387struct complex @{double real; double imag;@} v;
474c8240 10388@end smallexample
c906108c
SS
10389
10390@noindent
10391the two commands give this output:
10392
474c8240 10393@smallexample
c906108c
SS
10394@group
10395(@value{GDBP}) whatis v
10396type = struct complex
10397(@value{GDBP}) ptype v
10398type = struct complex @{
10399 double real;
10400 double imag;
10401@}
10402@end group
474c8240 10403@end smallexample
c906108c
SS
10404
10405@noindent
10406As with @code{whatis}, using @code{ptype} without an argument refers to
10407the type of @code{$}, the last value in the value history.
10408
ab1adacd
EZ
10409@cindex incomplete type
10410Sometimes, programs use opaque data types or incomplete specifications
10411of complex data structure. If the debug information included in the
10412program does not allow @value{GDBN} to display a full declaration of
10413the data type, it will say @samp{<incomplete type>}. For example,
10414given these declarations:
10415
10416@smallexample
10417 struct foo;
10418 struct foo *fooptr;
10419@end smallexample
10420
10421@noindent
10422but no definition for @code{struct foo} itself, @value{GDBN} will say:
10423
10424@smallexample
10425 (gdb) ptype foo
10426 $1 = <incomplete type>
10427@end smallexample
10428
10429@noindent
10430``Incomplete type'' is C terminology for data types that are not
10431completely specified.
10432
c906108c
SS
10433@kindex info types
10434@item info types @var{regexp}
10435@itemx info types
09d4efe1
EZ
10436Print a brief description of all types whose names match the regular
10437expression @var{regexp} (or all types in your program, if you supply
10438no argument). Each complete typename is matched as though it were a
10439complete line; thus, @samp{i type value} gives information on all
10440types in your program whose names include the string @code{value}, but
10441@samp{i type ^value$} gives information only on types whose complete
10442name is @code{value}.
c906108c
SS
10443
10444This command differs from @code{ptype} in two ways: first, like
10445@code{whatis}, it does not print a detailed description; second, it
10446lists all source files where a type is defined.
10447
b37052ae
EZ
10448@kindex info scope
10449@cindex local variables
09d4efe1 10450@item info scope @var{location}
b37052ae 10451List all the variables local to a particular scope. This command
09d4efe1
EZ
10452accepts a @var{location} argument---a function name, a source line, or
10453an address preceded by a @samp{*}, and prints all the variables local
10454to the scope defined by that location. For example:
b37052ae
EZ
10455
10456@smallexample
10457(@value{GDBP}) @b{info scope command_line_handler}
10458Scope for command_line_handler:
10459Symbol rl is an argument at stack/frame offset 8, length 4.
10460Symbol linebuffer is in static storage at address 0x150a18, length 4.
10461Symbol linelength is in static storage at address 0x150a1c, length 4.
10462Symbol p is a local variable in register $esi, length 4.
10463Symbol p1 is a local variable in register $ebx, length 4.
10464Symbol nline is a local variable in register $edx, length 4.
10465Symbol repeat is a local variable at frame offset -8, length 4.
10466@end smallexample
10467
f5c37c66
EZ
10468@noindent
10469This command is especially useful for determining what data to collect
10470during a @dfn{trace experiment}, see @ref{Tracepoint Actions,
10471collect}.
10472
c906108c
SS
10473@kindex info source
10474@item info source
919d772c
JB
10475Show information about the current source file---that is, the source file for
10476the function containing the current point of execution:
10477@itemize @bullet
10478@item
10479the name of the source file, and the directory containing it,
10480@item
10481the directory it was compiled in,
10482@item
10483its length, in lines,
10484@item
10485which programming language it is written in,
10486@item
10487whether the executable includes debugging information for that file, and
10488if so, what format the information is in (e.g., STABS, Dwarf 2, etc.), and
10489@item
10490whether the debugging information includes information about
10491preprocessor macros.
10492@end itemize
10493
c906108c
SS
10494
10495@kindex info sources
10496@item info sources
10497Print the names of all source files in your program for which there is
10498debugging information, organized into two lists: files whose symbols
10499have already been read, and files whose symbols will be read when needed.
10500
10501@kindex info functions
10502@item info functions
10503Print the names and data types of all defined functions.
10504
10505@item info functions @var{regexp}
10506Print the names and data types of all defined functions
10507whose names contain a match for regular expression @var{regexp}.
10508Thus, @samp{info fun step} finds all functions whose names
10509include @code{step}; @samp{info fun ^step} finds those whose names
b383017d 10510start with @code{step}. If a function name contains characters
c1468174 10511that conflict with the regular expression language (e.g.@:
1c5dfdad 10512@samp{operator*()}), they may be quoted with a backslash.
c906108c
SS
10513
10514@kindex info variables
10515@item info variables
10516Print the names and data types of all variables that are declared
6ca652b0 10517outside of functions (i.e.@: excluding local variables).
c906108c
SS
10518
10519@item info variables @var{regexp}
10520Print the names and data types of all variables (except for local
10521variables) whose names contain a match for regular expression
10522@var{regexp}.
10523
b37303ee 10524@kindex info classes
721c2651 10525@cindex Objective-C, classes and selectors
b37303ee
AF
10526@item info classes
10527@itemx info classes @var{regexp}
10528Display all Objective-C classes in your program, or
10529(with the @var{regexp} argument) all those matching a particular regular
10530expression.
10531
10532@kindex info selectors
10533@item info selectors
10534@itemx info selectors @var{regexp}
10535Display all Objective-C selectors in your program, or
10536(with the @var{regexp} argument) all those matching a particular regular
10537expression.
10538
c906108c
SS
10539@ignore
10540This was never implemented.
10541@kindex info methods
10542@item info methods
10543@itemx info methods @var{regexp}
10544The @code{info methods} command permits the user to examine all defined
b37052ae
EZ
10545methods within C@t{++} program, or (with the @var{regexp} argument) a
10546specific set of methods found in the various C@t{++} classes. Many
10547C@t{++} classes provide a large number of methods. Thus, the output
c906108c
SS
10548from the @code{ptype} command can be overwhelming and hard to use. The
10549@code{info-methods} command filters the methods, printing only those
10550which match the regular-expression @var{regexp}.
10551@end ignore
10552
c906108c
SS
10553@cindex reloading symbols
10554Some systems allow individual object files that make up your program to
7a292a7a
SS
10555be replaced without stopping and restarting your program. For example,
10556in VxWorks you can simply recompile a defective object file and keep on
10557running. If you are running on one of these systems, you can allow
10558@value{GDBN} to reload the symbols for automatically relinked modules:
c906108c
SS
10559
10560@table @code
10561@kindex set symbol-reloading
10562@item set symbol-reloading on
10563Replace symbol definitions for the corresponding source file when an
10564object file with a particular name is seen again.
10565
10566@item set symbol-reloading off
6d2ebf8b
SS
10567Do not replace symbol definitions when encountering object files of the
10568same name more than once. This is the default state; if you are not
10569running on a system that permits automatic relinking of modules, you
10570should leave @code{symbol-reloading} off, since otherwise @value{GDBN}
10571may discard symbols when linking large programs, that may contain
10572several modules (from different directories or libraries) with the same
10573name.
c906108c
SS
10574
10575@kindex show symbol-reloading
10576@item show symbol-reloading
10577Show the current @code{on} or @code{off} setting.
10578@end table
c906108c 10579
9c16f35a 10580@cindex opaque data types
c906108c
SS
10581@kindex set opaque-type-resolution
10582@item set opaque-type-resolution on
10583Tell @value{GDBN} to resolve opaque types. An opaque type is a type
10584declared as a pointer to a @code{struct}, @code{class}, or
10585@code{union}---for example, @code{struct MyType *}---that is used in one
10586source file although the full declaration of @code{struct MyType} is in
10587another source file. The default is on.
10588
10589A change in the setting of this subcommand will not take effect until
10590the next time symbols for a file are loaded.
10591
10592@item set opaque-type-resolution off
10593Tell @value{GDBN} not to resolve opaque types. In this case, the type
10594is printed as follows:
10595@smallexample
10596@{<no data fields>@}
10597@end smallexample
10598
10599@kindex show opaque-type-resolution
10600@item show opaque-type-resolution
10601Show whether opaque types are resolved or not.
c906108c
SS
10602
10603@kindex maint print symbols
10604@cindex symbol dump
10605@kindex maint print psymbols
10606@cindex partial symbol dump
10607@item maint print symbols @var{filename}
10608@itemx maint print psymbols @var{filename}
10609@itemx maint print msymbols @var{filename}
10610Write a dump of debugging symbol data into the file @var{filename}.
10611These commands are used to debug the @value{GDBN} symbol-reading code. Only
10612symbols with debugging data are included. If you use @samp{maint print
10613symbols}, @value{GDBN} includes all the symbols for which it has already
10614collected full details: that is, @var{filename} reflects symbols for
10615only those files whose symbols @value{GDBN} has read. You can use the
10616command @code{info sources} to find out which files these are. If you
10617use @samp{maint print psymbols} instead, the dump shows information about
10618symbols that @value{GDBN} only knows partially---that is, symbols defined in
10619files that @value{GDBN} has skimmed, but not yet read completely. Finally,
10620@samp{maint print msymbols} dumps just the minimal symbol information
10621required for each object file from which @value{GDBN} has read some symbols.
10622@xref{Files, ,Commands to specify files}, for a discussion of how
10623@value{GDBN} reads symbols (in the description of @code{symbol-file}).
44ea7b70 10624
5e7b2f39
JB
10625@kindex maint info symtabs
10626@kindex maint info psymtabs
44ea7b70
JB
10627@cindex listing @value{GDBN}'s internal symbol tables
10628@cindex symbol tables, listing @value{GDBN}'s internal
10629@cindex full symbol tables, listing @value{GDBN}'s internal
10630@cindex partial symbol tables, listing @value{GDBN}'s internal
5e7b2f39
JB
10631@item maint info symtabs @r{[} @var{regexp} @r{]}
10632@itemx maint info psymtabs @r{[} @var{regexp} @r{]}
44ea7b70
JB
10633
10634List the @code{struct symtab} or @code{struct partial_symtab}
10635structures whose names match @var{regexp}. If @var{regexp} is not
10636given, list them all. The output includes expressions which you can
10637copy into a @value{GDBN} debugging this one to examine a particular
10638structure in more detail. For example:
10639
10640@smallexample
5e7b2f39 10641(@value{GDBP}) maint info psymtabs dwarf2read
44ea7b70
JB
10642@{ objfile /home/gnu/build/gdb/gdb
10643 ((struct objfile *) 0x82e69d0)
b383017d 10644 @{ psymtab /home/gnu/src/gdb/dwarf2read.c
44ea7b70
JB
10645 ((struct partial_symtab *) 0x8474b10)
10646 readin no
10647 fullname (null)
10648 text addresses 0x814d3c8 -- 0x8158074
10649 globals (* (struct partial_symbol **) 0x8507a08 @@ 9)
10650 statics (* (struct partial_symbol **) 0x40e95b78 @@ 2882)
10651 dependencies (none)
10652 @}
10653@}
5e7b2f39 10654(@value{GDBP}) maint info symtabs
44ea7b70
JB
10655(@value{GDBP})
10656@end smallexample
10657@noindent
10658We see that there is one partial symbol table whose filename contains
10659the string @samp{dwarf2read}, belonging to the @samp{gdb} executable;
10660and we see that @value{GDBN} has not read in any symtabs yet at all.
10661If we set a breakpoint on a function, that will cause @value{GDBN} to
10662read the symtab for the compilation unit containing that function:
10663
10664@smallexample
10665(@value{GDBP}) break dwarf2_psymtab_to_symtab
10666Breakpoint 1 at 0x814e5da: file /home/gnu/src/gdb/dwarf2read.c,
10667line 1574.
5e7b2f39 10668(@value{GDBP}) maint info symtabs
b383017d 10669@{ objfile /home/gnu/build/gdb/gdb
44ea7b70 10670 ((struct objfile *) 0x82e69d0)
b383017d 10671 @{ symtab /home/gnu/src/gdb/dwarf2read.c
44ea7b70
JB
10672 ((struct symtab *) 0x86c1f38)
10673 dirname (null)
10674 fullname (null)
10675 blockvector ((struct blockvector *) 0x86c1bd0) (primary)
10676 debugformat DWARF 2
10677 @}
10678@}
b383017d 10679(@value{GDBP})
44ea7b70 10680@end smallexample
c906108c
SS
10681@end table
10682
44ea7b70 10683
6d2ebf8b 10684@node Altering
c906108c
SS
10685@chapter Altering Execution
10686
10687Once you think you have found an error in your program, you might want to
10688find out for certain whether correcting the apparent error would lead to
10689correct results in the rest of the run. You can find the answer by
10690experiment, using the @value{GDBN} features for altering execution of the
10691program.
10692
10693For example, you can store new values into variables or memory
7a292a7a
SS
10694locations, give your program a signal, restart it at a different
10695address, or even return prematurely from a function.
c906108c
SS
10696
10697@menu
10698* Assignment:: Assignment to variables
10699* Jumping:: Continuing at a different address
c906108c 10700* Signaling:: Giving your program a signal
c906108c
SS
10701* Returning:: Returning from a function
10702* Calling:: Calling your program's functions
10703* Patching:: Patching your program
10704@end menu
10705
6d2ebf8b 10706@node Assignment
c906108c
SS
10707@section Assignment to variables
10708
10709@cindex assignment
10710@cindex setting variables
10711To alter the value of a variable, evaluate an assignment expression.
10712@xref{Expressions, ,Expressions}. For example,
10713
474c8240 10714@smallexample
c906108c 10715print x=4
474c8240 10716@end smallexample
c906108c
SS
10717
10718@noindent
10719stores the value 4 into the variable @code{x}, and then prints the
5d161b24 10720value of the assignment expression (which is 4).
c906108c
SS
10721@xref{Languages, ,Using @value{GDBN} with Different Languages}, for more
10722information on operators in supported languages.
c906108c
SS
10723
10724@kindex set variable
10725@cindex variables, setting
10726If you are not interested in seeing the value of the assignment, use the
10727@code{set} command instead of the @code{print} command. @code{set} is
10728really the same as @code{print} except that the expression's value is
10729not printed and is not put in the value history (@pxref{Value History,
10730,Value history}). The expression is evaluated only for its effects.
10731
c906108c
SS
10732If the beginning of the argument string of the @code{set} command
10733appears identical to a @code{set} subcommand, use the @code{set
10734variable} command instead of just @code{set}. This command is identical
10735to @code{set} except for its lack of subcommands. For example, if your
10736program has a variable @code{width}, you get an error if you try to set
10737a new value with just @samp{set width=13}, because @value{GDBN} has the
10738command @code{set width}:
10739
474c8240 10740@smallexample
c906108c
SS
10741(@value{GDBP}) whatis width
10742type = double
10743(@value{GDBP}) p width
10744$4 = 13
10745(@value{GDBP}) set width=47
10746Invalid syntax in expression.
474c8240 10747@end smallexample
c906108c
SS
10748
10749@noindent
10750The invalid expression, of course, is @samp{=47}. In
10751order to actually set the program's variable @code{width}, use
10752
474c8240 10753@smallexample
c906108c 10754(@value{GDBP}) set var width=47
474c8240 10755@end smallexample
53a5351d 10756
c906108c
SS
10757Because the @code{set} command has many subcommands that can conflict
10758with the names of program variables, it is a good idea to use the
10759@code{set variable} command instead of just @code{set}. For example, if
10760your program has a variable @code{g}, you run into problems if you try
10761to set a new value with just @samp{set g=4}, because @value{GDBN} has
10762the command @code{set gnutarget}, abbreviated @code{set g}:
10763
474c8240 10764@smallexample
c906108c
SS
10765@group
10766(@value{GDBP}) whatis g
10767type = double
10768(@value{GDBP}) p g
10769$1 = 1
10770(@value{GDBP}) set g=4
2df3850c 10771(@value{GDBP}) p g
c906108c
SS
10772$2 = 1
10773(@value{GDBP}) r
10774The program being debugged has been started already.
10775Start it from the beginning? (y or n) y
10776Starting program: /home/smith/cc_progs/a.out
6d2ebf8b
SS
10777"/home/smith/cc_progs/a.out": can't open to read symbols:
10778 Invalid bfd target.
c906108c
SS
10779(@value{GDBP}) show g
10780The current BFD target is "=4".
10781@end group
474c8240 10782@end smallexample
c906108c
SS
10783
10784@noindent
10785The program variable @code{g} did not change, and you silently set the
10786@code{gnutarget} to an invalid value. In order to set the variable
10787@code{g}, use
10788
474c8240 10789@smallexample
c906108c 10790(@value{GDBP}) set var g=4
474c8240 10791@end smallexample
c906108c
SS
10792
10793@value{GDBN} allows more implicit conversions in assignments than C; you can
10794freely store an integer value into a pointer variable or vice versa,
10795and you can convert any structure to any other structure that is the
10796same length or shorter.
10797@comment FIXME: how do structs align/pad in these conversions?
10798@comment /doc@cygnus.com 18dec1990
10799
10800To store values into arbitrary places in memory, use the @samp{@{@dots{}@}}
10801construct to generate a value of specified type at a specified address
10802(@pxref{Expressions, ,Expressions}). For example, @code{@{int@}0x83040} refers
10803to memory location @code{0x83040} as an integer (which implies a certain size
10804and representation in memory), and
10805
474c8240 10806@smallexample
c906108c 10807set @{int@}0x83040 = 4
474c8240 10808@end smallexample
c906108c
SS
10809
10810@noindent
10811stores the value 4 into that memory location.
10812
6d2ebf8b 10813@node Jumping
c906108c
SS
10814@section Continuing at a different address
10815
10816Ordinarily, when you continue your program, you do so at the place where
10817it stopped, with the @code{continue} command. You can instead continue at
10818an address of your own choosing, with the following commands:
10819
10820@table @code
10821@kindex jump
10822@item jump @var{linespec}
10823Resume execution at line @var{linespec}. Execution stops again
10824immediately if there is a breakpoint there. @xref{List, ,Printing
10825source lines}, for a description of the different forms of
10826@var{linespec}. It is common practice to use the @code{tbreak} command
10827in conjunction with @code{jump}. @xref{Set Breaks, ,Setting
10828breakpoints}.
10829
10830The @code{jump} command does not change the current stack frame, or
10831the stack pointer, or the contents of any memory location or any
10832register other than the program counter. If line @var{linespec} is in
10833a different function from the one currently executing, the results may
10834be bizarre if the two functions expect different patterns of arguments or
10835of local variables. For this reason, the @code{jump} command requests
10836confirmation if the specified line is not in the function currently
10837executing. However, even bizarre results are predictable if you are
10838well acquainted with the machine-language code of your program.
10839
10840@item jump *@var{address}
10841Resume execution at the instruction at address @var{address}.
10842@end table
10843
c906108c 10844@c Doesn't work on HP-UX; have to set $pcoqh and $pcoqt.
53a5351d
JM
10845On many systems, you can get much the same effect as the @code{jump}
10846command by storing a new value into the register @code{$pc}. The
10847difference is that this does not start your program running; it only
10848changes the address of where it @emph{will} run when you continue. For
10849example,
c906108c 10850
474c8240 10851@smallexample
c906108c 10852set $pc = 0x485
474c8240 10853@end smallexample
c906108c
SS
10854
10855@noindent
10856makes the next @code{continue} command or stepping command execute at
10857address @code{0x485}, rather than at the address where your program stopped.
10858@xref{Continuing and Stepping, ,Continuing and stepping}.
c906108c
SS
10859
10860The most common occasion to use the @code{jump} command is to back
10861up---perhaps with more breakpoints set---over a portion of a program
10862that has already executed, in order to examine its execution in more
10863detail.
10864
c906108c 10865@c @group
6d2ebf8b 10866@node Signaling
c906108c 10867@section Giving your program a signal
9c16f35a 10868@cindex deliver a signal to a program
c906108c
SS
10869
10870@table @code
10871@kindex signal
10872@item signal @var{signal}
10873Resume execution where your program stopped, but immediately give it the
10874signal @var{signal}. @var{signal} can be the name or the number of a
10875signal. For example, on many systems @code{signal 2} and @code{signal
10876SIGINT} are both ways of sending an interrupt signal.
10877
10878Alternatively, if @var{signal} is zero, continue execution without
10879giving a signal. This is useful when your program stopped on account of
10880a signal and would ordinary see the signal when resumed with the
10881@code{continue} command; @samp{signal 0} causes it to resume without a
10882signal.
10883
10884@code{signal} does not repeat when you press @key{RET} a second time
10885after executing the command.
10886@end table
10887@c @end group
10888
10889Invoking the @code{signal} command is not the same as invoking the
10890@code{kill} utility from the shell. Sending a signal with @code{kill}
10891causes @value{GDBN} to decide what to do with the signal depending on
10892the signal handling tables (@pxref{Signals}). The @code{signal} command
10893passes the signal directly to your program.
10894
c906108c 10895
6d2ebf8b 10896@node Returning
c906108c
SS
10897@section Returning from a function
10898
10899@table @code
10900@cindex returning from a function
10901@kindex return
10902@item return
10903@itemx return @var{expression}
10904You can cancel execution of a function call with the @code{return}
10905command. If you give an
10906@var{expression} argument, its value is used as the function's return
10907value.
10908@end table
10909
10910When you use @code{return}, @value{GDBN} discards the selected stack frame
10911(and all frames within it). You can think of this as making the
10912discarded frame return prematurely. If you wish to specify a value to
10913be returned, give that value as the argument to @code{return}.
10914
10915This pops the selected stack frame (@pxref{Selection, ,Selecting a
10916frame}), and any other frames inside of it, leaving its caller as the
10917innermost remaining frame. That frame becomes selected. The
10918specified value is stored in the registers used for returning values
10919of functions.
10920
10921The @code{return} command does not resume execution; it leaves the
10922program stopped in the state that would exist if the function had just
10923returned. In contrast, the @code{finish} command (@pxref{Continuing
10924and Stepping, ,Continuing and stepping}) resumes execution until the
10925selected stack frame returns naturally.
10926
6d2ebf8b 10927@node Calling
c906108c
SS
10928@section Calling program functions
10929
f8568604 10930@table @code
c906108c 10931@cindex calling functions
f8568604
EZ
10932@cindex inferior functions, calling
10933@item print @var{expr}
9c16f35a 10934Evaluate the expression @var{expr} and display the resuling value.
f8568604
EZ
10935@var{expr} may include calls to functions in the program being
10936debugged.
10937
c906108c 10938@kindex call
c906108c
SS
10939@item call @var{expr}
10940Evaluate the expression @var{expr} without displaying @code{void}
10941returned values.
c906108c
SS
10942
10943You can use this variant of the @code{print} command if you want to
f8568604
EZ
10944execute a function from your program that does not return anything
10945(a.k.a.@: @dfn{a void function}), but without cluttering the output
10946with @code{void} returned values that @value{GDBN} will otherwise
10947print. If the result is not void, it is printed and saved in the
10948value history.
10949@end table
10950
9c16f35a
EZ
10951It is possible for the function you call via the @code{print} or
10952@code{call} command to generate a signal (e.g., if there's a bug in
10953the function, or if you passed it incorrect arguments). What happens
10954in that case is controlled by the @code{set unwindonsignal} command.
10955
10956@table @code
10957@item set unwindonsignal
10958@kindex set unwindonsignal
10959@cindex unwind stack in called functions
10960@cindex call dummy stack unwinding
10961Set unwinding of the stack if a signal is received while in a function
10962that @value{GDBN} called in the program being debugged. If set to on,
10963@value{GDBN} unwinds the stack it created for the call and restores
10964the context to what it was before the call. If set to off (the
10965default), @value{GDBN} stops in the frame where the signal was
10966received.
10967
10968@item show unwindonsignal
10969@kindex show unwindonsignal
10970Show the current setting of stack unwinding in the functions called by
10971@value{GDBN}.
10972@end table
10973
f8568604
EZ
10974@cindex weak alias functions
10975Sometimes, a function you wish to call is actually a @dfn{weak alias}
10976for another function. In such case, @value{GDBN} might not pick up
10977the type information, including the types of the function arguments,
10978which causes @value{GDBN} to call the inferior function incorrectly.
10979As a result, the called function will function erroneously and may
10980even crash. A solution to that is to use the name of the aliased
10981function instead.
c906108c 10982
6d2ebf8b 10983@node Patching
c906108c 10984@section Patching programs
7a292a7a 10985
c906108c
SS
10986@cindex patching binaries
10987@cindex writing into executables
c906108c 10988@cindex writing into corefiles
c906108c 10989
7a292a7a
SS
10990By default, @value{GDBN} opens the file containing your program's
10991executable code (or the corefile) read-only. This prevents accidental
10992alterations to machine code; but it also prevents you from intentionally
10993patching your program's binary.
c906108c
SS
10994
10995If you'd like to be able to patch the binary, you can specify that
10996explicitly with the @code{set write} command. For example, you might
10997want to turn on internal debugging flags, or even to make emergency
10998repairs.
10999
11000@table @code
11001@kindex set write
11002@item set write on
11003@itemx set write off
7a292a7a
SS
11004If you specify @samp{set write on}, @value{GDBN} opens executable and
11005core files for both reading and writing; if you specify @samp{set write
c906108c
SS
11006off} (the default), @value{GDBN} opens them read-only.
11007
11008If you have already loaded a file, you must load it again (using the
7a292a7a
SS
11009@code{exec-file} or @code{core-file} command) after changing @code{set
11010write}, for your new setting to take effect.
c906108c
SS
11011
11012@item show write
11013@kindex show write
7a292a7a
SS
11014Display whether executable files and core files are opened for writing
11015as well as reading.
c906108c
SS
11016@end table
11017
6d2ebf8b 11018@node GDB Files
c906108c
SS
11019@chapter @value{GDBN} Files
11020
7a292a7a
SS
11021@value{GDBN} needs to know the file name of the program to be debugged,
11022both in order to read its symbol table and in order to start your
11023program. To debug a core dump of a previous run, you must also tell
11024@value{GDBN} the name of the core dump file.
c906108c
SS
11025
11026@menu
11027* Files:: Commands to specify files
5b5d99cf 11028* Separate Debug Files:: Debugging information in separate files
c906108c
SS
11029* Symbol Errors:: Errors reading symbol files
11030@end menu
11031
6d2ebf8b 11032@node Files
c906108c 11033@section Commands to specify files
c906108c 11034
7a292a7a 11035@cindex symbol table
c906108c 11036@cindex core dump file
7a292a7a
SS
11037
11038You may want to specify executable and core dump file names. The usual
11039way to do this is at start-up time, using the arguments to
11040@value{GDBN}'s start-up commands (@pxref{Invocation, , Getting In and
11041Out of @value{GDBN}}).
c906108c
SS
11042
11043Occasionally it is necessary to change to a different file during a
397ca115
EZ
11044@value{GDBN} session. Or you may run @value{GDBN} and forget to
11045specify a file you want to use. Or you are debugging a remote target
11046via @code{gdbserver} (@pxref{Server, file}). In these situations the
11047@value{GDBN} commands to specify new files are useful.
c906108c
SS
11048
11049@table @code
11050@cindex executable file
11051@kindex file
11052@item file @var{filename}
11053Use @var{filename} as the program to be debugged. It is read for its
11054symbols and for the contents of pure memory. It is also the program
11055executed when you use the @code{run} command. If you do not specify a
5d161b24
DB
11056directory and the file is not found in the @value{GDBN} working directory,
11057@value{GDBN} uses the environment variable @code{PATH} as a list of
11058directories to search, just as the shell does when looking for a program
11059to run. You can change the value of this variable, for both @value{GDBN}
c906108c
SS
11060and your program, using the @code{path} command.
11061
fc8be69e
EZ
11062@cindex unlinked object files
11063@cindex patching object files
11064You can load unlinked object @file{.o} files into @value{GDBN} using
11065the @code{file} command. You will not be able to ``run'' an object
11066file, but you can disassemble functions and inspect variables. Also,
11067if the underlying BFD functionality supports it, you could use
11068@kbd{gdb -write} to patch object files using this technique. Note
11069that @value{GDBN} can neither interpret nor modify relocations in this
11070case, so branches and some initialized variables will appear to go to
11071the wrong place. But this feature is still handy from time to time.
11072
c906108c
SS
11073@item file
11074@code{file} with no argument makes @value{GDBN} discard any information it
11075has on both executable file and the symbol table.
11076
11077@kindex exec-file
11078@item exec-file @r{[} @var{filename} @r{]}
11079Specify that the program to be run (but not the symbol table) is found
11080in @var{filename}. @value{GDBN} searches the environment variable @code{PATH}
11081if necessary to locate your program. Omitting @var{filename} means to
11082discard information on the executable file.
11083
11084@kindex symbol-file
11085@item symbol-file @r{[} @var{filename} @r{]}
11086Read symbol table information from file @var{filename}. @code{PATH} is
11087searched when necessary. Use the @code{file} command to get both symbol
11088table and program to run from the same file.
11089
11090@code{symbol-file} with no argument clears out @value{GDBN} information on your
11091program's symbol table.
11092
ae5a43e0
DJ
11093The @code{symbol-file} command causes @value{GDBN} to forget the contents of
11094some breakpoints and auto-display expressions. This is because they may
11095contain pointers to the internal data recording symbols and data types,
11096which are part of the old symbol table data being discarded inside
11097@value{GDBN}.
c906108c
SS
11098
11099@code{symbol-file} does not repeat if you press @key{RET} again after
11100executing it once.
11101
11102When @value{GDBN} is configured for a particular environment, it
11103understands debugging information in whatever format is the standard
11104generated for that environment; you may use either a @sc{gnu} compiler, or
11105other compilers that adhere to the local conventions.
c906108c
SS
11106Best results are usually obtained from @sc{gnu} compilers; for example,
11107using @code{@value{GCC}} you can generate debugging information for
11108optimized code.
c906108c
SS
11109
11110For most kinds of object files, with the exception of old SVR3 systems
11111using COFF, the @code{symbol-file} command does not normally read the
11112symbol table in full right away. Instead, it scans the symbol table
11113quickly to find which source files and which symbols are present. The
11114details are read later, one source file at a time, as they are needed.
11115
11116The purpose of this two-stage reading strategy is to make @value{GDBN}
11117start up faster. For the most part, it is invisible except for
11118occasional pauses while the symbol table details for a particular source
11119file are being read. (The @code{set verbose} command can turn these
11120pauses into messages if desired. @xref{Messages/Warnings, ,Optional
11121warnings and messages}.)
11122
c906108c
SS
11123We have not implemented the two-stage strategy for COFF yet. When the
11124symbol table is stored in COFF format, @code{symbol-file} reads the
11125symbol table data in full right away. Note that ``stabs-in-COFF''
11126still does the two-stage strategy, since the debug info is actually
11127in stabs format.
11128
11129@kindex readnow
11130@cindex reading symbols immediately
11131@cindex symbols, reading immediately
a94ab193
EZ
11132@item symbol-file @var{filename} @r{[} -readnow @r{]}
11133@itemx file @var{filename} @r{[} -readnow @r{]}
c906108c
SS
11134You can override the @value{GDBN} two-stage strategy for reading symbol
11135tables by using the @samp{-readnow} option with any of the commands that
11136load symbol table information, if you want to be sure @value{GDBN} has the
5d161b24 11137entire symbol table available.
c906108c 11138
c906108c
SS
11139@c FIXME: for now no mention of directories, since this seems to be in
11140@c flux. 13mar1992 status is that in theory GDB would look either in
11141@c current dir or in same dir as myprog; but issues like competing
11142@c GDB's, or clutter in system dirs, mean that in practice right now
11143@c only current dir is used. FFish says maybe a special GDB hierarchy
11144@c (eg rooted in val of env var GDBSYMS) could exist for mappable symbol
11145@c files.
11146
c906108c 11147@kindex core-file
09d4efe1 11148@item core-file @r{[}@var{filename}@r{]}
4644b6e3 11149@itemx core
c906108c
SS
11150Specify the whereabouts of a core dump file to be used as the ``contents
11151of memory''. Traditionally, core files contain only some parts of the
11152address space of the process that generated them; @value{GDBN} can access the
11153executable file itself for other parts.
11154
11155@code{core-file} with no argument specifies that no core file is
11156to be used.
11157
11158Note that the core file is ignored when your program is actually running
7a292a7a
SS
11159under @value{GDBN}. So, if you have been running your program and you
11160wish to debug a core file instead, you must kill the subprocess in which
11161the program is running. To do this, use the @code{kill} command
c906108c 11162(@pxref{Kill Process, ,Killing the child process}).
c906108c 11163
c906108c
SS
11164@kindex add-symbol-file
11165@cindex dynamic linking
11166@item add-symbol-file @var{filename} @var{address}
a94ab193 11167@itemx add-symbol-file @var{filename} @var{address} @r{[} -readnow @r{]}
17d9d558 11168@itemx add-symbol-file @var{filename} @r{-s}@var{section} @var{address} @dots{}
96a2c332
SS
11169The @code{add-symbol-file} command reads additional symbol table
11170information from the file @var{filename}. You would use this command
11171when @var{filename} has been dynamically loaded (by some other means)
11172into the program that is running. @var{address} should be the memory
11173address at which the file has been loaded; @value{GDBN} cannot figure
d167840f
EZ
11174this out for itself. You can additionally specify an arbitrary number
11175of @samp{@r{-s}@var{section} @var{address}} pairs, to give an explicit
11176section name and base address for that section. You can specify any
11177@var{address} as an expression.
c906108c
SS
11178
11179The symbol table of the file @var{filename} is added to the symbol table
11180originally read with the @code{symbol-file} command. You can use the
96a2c332
SS
11181@code{add-symbol-file} command any number of times; the new symbol data
11182thus read keeps adding to the old. To discard all old symbol data
11183instead, use the @code{symbol-file} command without any arguments.
c906108c 11184
17d9d558
JB
11185@cindex relocatable object files, reading symbols from
11186@cindex object files, relocatable, reading symbols from
11187@cindex reading symbols from relocatable object files
11188@cindex symbols, reading from relocatable object files
11189@cindex @file{.o} files, reading symbols from
11190Although @var{filename} is typically a shared library file, an
11191executable file, or some other object file which has been fully
11192relocated for loading into a process, you can also load symbolic
11193information from relocatable @file{.o} files, as long as:
11194
11195@itemize @bullet
11196@item
11197the file's symbolic information refers only to linker symbols defined in
11198that file, not to symbols defined by other object files,
11199@item
11200every section the file's symbolic information refers to has actually
11201been loaded into the inferior, as it appears in the file, and
11202@item
11203you can determine the address at which every section was loaded, and
11204provide these to the @code{add-symbol-file} command.
11205@end itemize
11206
11207@noindent
11208Some embedded operating systems, like Sun Chorus and VxWorks, can load
11209relocatable files into an already running program; such systems
11210typically make the requirements above easy to meet. However, it's
11211important to recognize that many native systems use complex link
49efadf5 11212procedures (@code{.linkonce} section factoring and C@t{++} constructor table
17d9d558
JB
11213assembly, for example) that make the requirements difficult to meet. In
11214general, one cannot assume that using @code{add-symbol-file} to read a
11215relocatable object file's symbolic information will have the same effect
11216as linking the relocatable object file into the program in the normal
11217way.
11218
c906108c
SS
11219@code{add-symbol-file} does not repeat if you press @key{RET} after using it.
11220
c45da7e6
EZ
11221@kindex add-symbol-file-from-memory
11222@cindex @code{syscall DSO}
11223@cindex load symbols from memory
11224@item add-symbol-file-from-memory @var{address}
11225Load symbols from the given @var{address} in a dynamically loaded
11226object file whose image is mapped directly into the inferior's memory.
11227For example, the Linux kernel maps a @code{syscall DSO} into each
11228process's address space; this DSO provides kernel-specific code for
11229some system calls. The argument can be any expression whose
11230evaluation yields the address of the file's shared object file header.
11231For this command to work, you must have used @code{symbol-file} or
11232@code{exec-file} commands in advance.
11233
09d4efe1
EZ
11234@kindex add-shared-symbol-files
11235@kindex assf
11236@item add-shared-symbol-files @var{library-file}
11237@itemx assf @var{library-file}
11238The @code{add-shared-symbol-files} command can currently be used only
11239in the Cygwin build of @value{GDBN} on MS-Windows OS, where it is an
11240alias for the @code{dll-symbols} command (@pxref{Cygwin Native}).
11241@value{GDBN} automatically looks for shared libraries, however if
11242@value{GDBN} does not find yours, you can invoke
11243@code{add-shared-symbol-files}. It takes one argument: the shared
11244library's file name. @code{assf} is a shorthand alias for
11245@code{add-shared-symbol-files}.
c906108c 11246
c906108c 11247@kindex section
09d4efe1
EZ
11248@item section @var{section} @var{addr}
11249The @code{section} command changes the base address of the named
11250@var{section} of the exec file to @var{addr}. This can be used if the
11251exec file does not contain section addresses, (such as in the
11252@code{a.out} format), or when the addresses specified in the file
11253itself are wrong. Each section must be changed separately. The
11254@code{info files} command, described below, lists all the sections and
11255their addresses.
c906108c
SS
11256
11257@kindex info files
11258@kindex info target
11259@item info files
11260@itemx info target
7a292a7a
SS
11261@code{info files} and @code{info target} are synonymous; both print the
11262current target (@pxref{Targets, ,Specifying a Debugging Target}),
11263including the names of the executable and core dump files currently in
11264use by @value{GDBN}, and the files from which symbols were loaded. The
11265command @code{help target} lists all possible targets rather than
11266current ones.
11267
fe95c787
MS
11268@kindex maint info sections
11269@item maint info sections
11270Another command that can give you extra information about program sections
11271is @code{maint info sections}. In addition to the section information
11272displayed by @code{info files}, this command displays the flags and file
11273offset of each section in the executable and core dump files. In addition,
11274@code{maint info sections} provides the following command options (which
11275may be arbitrarily combined):
11276
11277@table @code
11278@item ALLOBJ
11279Display sections for all loaded object files, including shared libraries.
11280@item @var{sections}
6600abed 11281Display info only for named @var{sections}.
fe95c787
MS
11282@item @var{section-flags}
11283Display info only for sections for which @var{section-flags} are true.
11284The section flags that @value{GDBN} currently knows about are:
11285@table @code
11286@item ALLOC
11287Section will have space allocated in the process when loaded.
11288Set for all sections except those containing debug information.
11289@item LOAD
11290Section will be loaded from the file into the child process memory.
11291Set for pre-initialized code and data, clear for @code{.bss} sections.
11292@item RELOC
11293Section needs to be relocated before loading.
11294@item READONLY
11295Section cannot be modified by the child process.
11296@item CODE
11297Section contains executable code only.
6600abed 11298@item DATA
fe95c787
MS
11299Section contains data only (no executable code).
11300@item ROM
11301Section will reside in ROM.
11302@item CONSTRUCTOR
11303Section contains data for constructor/destructor lists.
11304@item HAS_CONTENTS
11305Section is not empty.
11306@item NEVER_LOAD
11307An instruction to the linker to not output the section.
11308@item COFF_SHARED_LIBRARY
11309A notification to the linker that the section contains
11310COFF shared library information.
11311@item IS_COMMON
11312Section contains common symbols.
11313@end table
11314@end table
6763aef9 11315@kindex set trust-readonly-sections
9c16f35a 11316@cindex read-only sections
6763aef9
MS
11317@item set trust-readonly-sections on
11318Tell @value{GDBN} that readonly sections in your object file
6ca652b0 11319really are read-only (i.e.@: that their contents will not change).
6763aef9
MS
11320In that case, @value{GDBN} can fetch values from these sections
11321out of the object file, rather than from the target program.
11322For some targets (notably embedded ones), this can be a significant
11323enhancement to debugging performance.
11324
11325The default is off.
11326
11327@item set trust-readonly-sections off
15110bc3 11328Tell @value{GDBN} not to trust readonly sections. This means that
6763aef9
MS
11329the contents of the section might change while the program is running,
11330and must therefore be fetched from the target when needed.
9c16f35a
EZ
11331
11332@item show trust-readonly-sections
11333Show the current setting of trusting readonly sections.
c906108c
SS
11334@end table
11335
11336All file-specifying commands allow both absolute and relative file names
11337as arguments. @value{GDBN} always converts the file name to an absolute file
11338name and remembers it that way.
11339
c906108c 11340@cindex shared libraries
9c16f35a
EZ
11341@value{GDBN} supports GNU/Linux, MS-Windows, HP-UX, SunOS, SVr4, Irix,
11342and IBM RS/6000 AIX shared libraries.
53a5351d 11343
c906108c
SS
11344@value{GDBN} automatically loads symbol definitions from shared libraries
11345when you use the @code{run} command, or when you examine a core file.
11346(Before you issue the @code{run} command, @value{GDBN} does not understand
11347references to a function in a shared library, however---unless you are
11348debugging a core file).
53a5351d
JM
11349
11350On HP-UX, if the program loads a library explicitly, @value{GDBN}
11351automatically loads the symbols at the time of the @code{shl_load} call.
11352
c906108c
SS
11353@c FIXME: some @value{GDBN} release may permit some refs to undef
11354@c FIXME...symbols---eg in a break cmd---assuming they are from a shared
11355@c FIXME...lib; check this from time to time when updating manual
11356
b7209cb4
FF
11357There are times, however, when you may wish to not automatically load
11358symbol definitions from shared libraries, such as when they are
11359particularly large or there are many of them.
11360
11361To control the automatic loading of shared library symbols, use the
11362commands:
11363
11364@table @code
11365@kindex set auto-solib-add
11366@item set auto-solib-add @var{mode}
11367If @var{mode} is @code{on}, symbols from all shared object libraries
11368will be loaded automatically when the inferior begins execution, you
11369attach to an independently started inferior, or when the dynamic linker
11370informs @value{GDBN} that a new library has been loaded. If @var{mode}
11371is @code{off}, symbols must be loaded manually, using the
11372@code{sharedlibrary} command. The default value is @code{on}.
11373
dcaf7c2c
EZ
11374@cindex memory used for symbol tables
11375If your program uses lots of shared libraries with debug info that
11376takes large amounts of memory, you can decrease the @value{GDBN}
11377memory footprint by preventing it from automatically loading the
11378symbols from shared libraries. To that end, type @kbd{set
11379auto-solib-add off} before running the inferior, then load each
11380library whose debug symbols you do need with @kbd{sharedlibrary
11381@var{regexp}}, where @var{regexp} is a regular expresion that matches
11382the libraries whose symbols you want to be loaded.
11383
b7209cb4
FF
11384@kindex show auto-solib-add
11385@item show auto-solib-add
11386Display the current autoloading mode.
11387@end table
11388
c45da7e6 11389@cindex load shared library
b7209cb4
FF
11390To explicitly load shared library symbols, use the @code{sharedlibrary}
11391command:
11392
c906108c
SS
11393@table @code
11394@kindex info sharedlibrary
11395@kindex info share
11396@item info share
11397@itemx info sharedlibrary
11398Print the names of the shared libraries which are currently loaded.
11399
11400@kindex sharedlibrary
11401@kindex share
11402@item sharedlibrary @var{regex}
11403@itemx share @var{regex}
c906108c
SS
11404Load shared object library symbols for files matching a
11405Unix regular expression.
11406As with files loaded automatically, it only loads shared libraries
11407required by your program for a core file or after typing @code{run}. If
11408@var{regex} is omitted all shared libraries required by your program are
11409loaded.
c45da7e6
EZ
11410
11411@item nosharedlibrary
11412@kindex nosharedlibrary
11413@cindex unload symbols from shared libraries
11414Unload all shared object library symbols. This discards all symbols
11415that have been loaded from all shared libraries. Symbols from shared
11416libraries that were loaded by explicit user requests are not
11417discarded.
c906108c
SS
11418@end table
11419
721c2651
EZ
11420Sometimes you may wish that @value{GDBN} stops and gives you control
11421when any of shared library events happen. Use the @code{set
11422stop-on-solib-events} command for this:
11423
11424@table @code
11425@item set stop-on-solib-events
11426@kindex set stop-on-solib-events
11427This command controls whether @value{GDBN} should give you control
11428when the dynamic linker notifies it about some shared library event.
11429The most common event of interest is loading or unloading of a new
11430shared library.
11431
11432@item show stop-on-solib-events
11433@kindex show stop-on-solib-events
11434Show whether @value{GDBN} stops and gives you control when shared
11435library events happen.
11436@end table
11437
f5ebfba0
DJ
11438Shared libraries are also supported in many cross or remote debugging
11439configurations. A copy of the target's libraries need to be present on the
11440host system; they need to be the same as the target libraries, although the
11441copies on the target can be stripped as long as the copies on the host are
11442not.
11443
59b7b46f
EZ
11444@cindex where to look for shared libraries
11445For remote debugging, you need to tell @value{GDBN} where the target
11446libraries are, so that it can load the correct copies---otherwise, it
11447may try to load the host's libraries. @value{GDBN} has two variables
11448to specify the search directories for target libraries.
f5ebfba0
DJ
11449
11450@table @code
59b7b46f 11451@cindex prefix for shared library file names
f5ebfba0
DJ
11452@kindex set solib-absolute-prefix
11453@item set solib-absolute-prefix @var{path}
11454If this variable is set, @var{path} will be used as a prefix for any
11455absolute shared library paths; many runtime loaders store the absolute
11456paths to the shared library in the target program's memory. If you use
11457@samp{solib-absolute-prefix} to find shared libraries, they need to be laid
11458out in the same way that they are on the target, with e.g.@: a
11459@file{/usr/lib} hierarchy under @var{path}.
11460
59b7b46f
EZ
11461@cindex default value of @samp{solib-absolute-prefix}
11462@cindex @samp{--with-sysroot}
f5ebfba0
DJ
11463You can set the default value of @samp{solib-absolute-prefix} by using the
11464configure-time @samp{--with-sysroot} option.
11465
11466@kindex show solib-absolute-prefix
11467@item show solib-absolute-prefix
11468Display the current shared library prefix.
11469
11470@kindex set solib-search-path
11471@item set solib-search-path @var{path}
11472If this variable is set, @var{path} is a colon-separated list of directories
11473to search for shared libraries. @samp{solib-search-path} is used after
11474@samp{solib-absolute-prefix} fails to locate the library, or if the path to
11475the library is relative instead of absolute. If you want to use
11476@samp{solib-search-path} instead of @samp{solib-absolute-prefix}, be sure to
11477set @samp{solib-absolute-prefix} to a nonexistant directory to prevent
11478@value{GDBN} from finding your host's libraries.
11479
11480@kindex show solib-search-path
11481@item show solib-search-path
11482Display the current shared library search path.
11483@end table
11484
5b5d99cf
JB
11485
11486@node Separate Debug Files
11487@section Debugging Information in Separate Files
11488@cindex separate debugging information files
11489@cindex debugging information in separate files
11490@cindex @file{.debug} subdirectories
11491@cindex debugging information directory, global
11492@cindex global debugging information directory
11493
11494@value{GDBN} allows you to put a program's debugging information in a
11495file separate from the executable itself, in a way that allows
11496@value{GDBN} to find and load the debugging information automatically.
11497Since debugging information can be very large --- sometimes larger
11498than the executable code itself --- some systems distribute debugging
11499information for their executables in separate files, which users can
11500install only when they need to debug a problem.
11501
11502If an executable's debugging information has been extracted to a
11503separate file, the executable should contain a @dfn{debug link} giving
11504the name of the debugging information file (with no directory
11505components), and a checksum of its contents. (The exact form of a
11506debug link is described below.) If the full name of the directory
11507containing the executable is @var{execdir}, and the executable has a
11508debug link that specifies the name @var{debugfile}, then @value{GDBN}
11509will automatically search for the debugging information file in three
11510places:
11511
11512@itemize @bullet
11513@item
11514the directory containing the executable file (that is, it will look
11515for a file named @file{@var{execdir}/@var{debugfile}},
11516@item
11517a subdirectory of that directory named @file{.debug} (that is, the
11518file @file{@var{execdir}/.debug/@var{debugfile}}, and
11519@item
11520a subdirectory of the global debug file directory that includes the
11521executable's full path, and the name from the link (that is, the file
11522@file{@var{globaldebugdir}/@var{execdir}/@var{debugfile}}, where
11523@var{globaldebugdir} is the global debug file directory, and
11524@var{execdir} has been turned into a relative path).
11525@end itemize
11526@noindent
11527@value{GDBN} checks under each of these names for a debugging
11528information file whose checksum matches that given in the link, and
11529reads the debugging information from the first one it finds.
11530
11531So, for example, if you ask @value{GDBN} to debug @file{/usr/bin/ls},
11532which has a link containing the name @file{ls.debug}, and the global
11533debug directory is @file{/usr/lib/debug}, then @value{GDBN} will look
11534for debug information in @file{/usr/bin/ls.debug},
11535@file{/usr/bin/.debug/ls.debug}, and
11536@file{/usr/lib/debug/usr/bin/ls.debug}.
11537
11538You can set the global debugging info directory's name, and view the
11539name @value{GDBN} is currently using.
11540
11541@table @code
11542
11543@kindex set debug-file-directory
11544@item set debug-file-directory @var{directory}
11545Set the directory which @value{GDBN} searches for separate debugging
11546information files to @var{directory}.
11547
11548@kindex show debug-file-directory
11549@item show debug-file-directory
11550Show the directory @value{GDBN} searches for separate debugging
11551information files.
11552
11553@end table
11554
11555@cindex @code{.gnu_debuglink} sections
11556@cindex debug links
11557A debug link is a special section of the executable file named
11558@code{.gnu_debuglink}. The section must contain:
11559
11560@itemize
11561@item
11562A filename, with any leading directory components removed, followed by
11563a zero byte,
11564@item
11565zero to three bytes of padding, as needed to reach the next four-byte
11566boundary within the section, and
11567@item
11568a four-byte CRC checksum, stored in the same endianness used for the
11569executable file itself. The checksum is computed on the debugging
11570information file's full contents by the function given below, passing
11571zero as the @var{crc} argument.
11572@end itemize
11573
11574Any executable file format can carry a debug link, as long as it can
11575contain a section named @code{.gnu_debuglink} with the contents
11576described above.
11577
11578The debugging information file itself should be an ordinary
11579executable, containing a full set of linker symbols, sections, and
11580debugging information. The sections of the debugging information file
11581should have the same names, addresses and sizes as the original file,
11582but they need not contain any data --- much like a @code{.bss} section
11583in an ordinary executable.
11584
11585As of December 2002, there is no standard GNU utility to produce
11586separated executable / debugging information file pairs. Ulrich
11587Drepper's @file{elfutils} package, starting with version 0.53,
11588contains a version of the @code{strip} command such that the command
11589@kbd{strip foo -f foo.debug} removes the debugging information from
11590the executable file @file{foo}, places it in the file
11591@file{foo.debug}, and leaves behind a debug link in @file{foo}.
11592
11593Since there are many different ways to compute CRC's (different
11594polynomials, reversals, byte ordering, etc.), the simplest way to
11595describe the CRC used in @code{.gnu_debuglink} sections is to give the
11596complete code for a function that computes it:
11597
4644b6e3 11598@kindex gnu_debuglink_crc32
5b5d99cf
JB
11599@smallexample
11600unsigned long
11601gnu_debuglink_crc32 (unsigned long crc,
11602 unsigned char *buf, size_t len)
11603@{
11604 static const unsigned long crc32_table[256] =
11605 @{
11606 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
11607 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
11608 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
11609 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
11610 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
11611 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
11612 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
11613 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
11614 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
11615 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
11616 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
11617 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
11618 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
11619 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
11620 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
11621 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
11622 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
11623 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
11624 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
11625 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
11626 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
11627 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
11628 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
11629 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
11630 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
11631 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
11632 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
11633 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
11634 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
11635 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
11636 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
11637 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
11638 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
11639 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
11640 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
11641 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
11642 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
11643 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
11644 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
11645 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
11646 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
11647 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
11648 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
11649 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
11650 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
11651 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
11652 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
11653 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
11654 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
11655 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
11656 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
11657 0x2d02ef8d
11658 @};
11659 unsigned char *end;
11660
11661 crc = ~crc & 0xffffffff;
11662 for (end = buf + len; buf < end; ++buf)
11663 crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
e7a3abfc 11664 return ~crc & 0xffffffff;
5b5d99cf
JB
11665@}
11666@end smallexample
11667
11668
6d2ebf8b 11669@node Symbol Errors
c906108c
SS
11670@section Errors reading symbol files
11671
11672While reading a symbol file, @value{GDBN} occasionally encounters problems,
11673such as symbol types it does not recognize, or known bugs in compiler
11674output. By default, @value{GDBN} does not notify you of such problems, since
11675they are relatively common and primarily of interest to people
11676debugging compilers. If you are interested in seeing information
11677about ill-constructed symbol tables, you can either ask @value{GDBN} to print
11678only one message about each such type of problem, no matter how many
11679times the problem occurs; or you can ask @value{GDBN} to print more messages,
11680to see how many times the problems occur, with the @code{set
11681complaints} command (@pxref{Messages/Warnings, ,Optional warnings and
11682messages}).
11683
11684The messages currently printed, and their meanings, include:
11685
11686@table @code
11687@item inner block not inside outer block in @var{symbol}
11688
11689The symbol information shows where symbol scopes begin and end
11690(such as at the start of a function or a block of statements). This
11691error indicates that an inner scope block is not fully contained
11692in its outer scope blocks.
11693
11694@value{GDBN} circumvents the problem by treating the inner block as if it had
11695the same scope as the outer block. In the error message, @var{symbol}
11696may be shown as ``@code{(don't know)}'' if the outer block is not a
11697function.
11698
11699@item block at @var{address} out of order
11700
11701The symbol information for symbol scope blocks should occur in
11702order of increasing addresses. This error indicates that it does not
11703do so.
11704
11705@value{GDBN} does not circumvent this problem, and has trouble
11706locating symbols in the source file whose symbols it is reading. (You
11707can often determine what source file is affected by specifying
11708@code{set verbose on}. @xref{Messages/Warnings, ,Optional warnings and
11709messages}.)
11710
11711@item bad block start address patched
11712
11713The symbol information for a symbol scope block has a start address
11714smaller than the address of the preceding source line. This is known
11715to occur in the SunOS 4.1.1 (and earlier) C compiler.
11716
11717@value{GDBN} circumvents the problem by treating the symbol scope block as
11718starting on the previous source line.
11719
11720@item bad string table offset in symbol @var{n}
11721
11722@cindex foo
11723Symbol number @var{n} contains a pointer into the string table which is
11724larger than the size of the string table.
11725
11726@value{GDBN} circumvents the problem by considering the symbol to have the
11727name @code{foo}, which may cause other problems if many symbols end up
11728with this name.
11729
11730@item unknown symbol type @code{0x@var{nn}}
11731
7a292a7a
SS
11732The symbol information contains new data types that @value{GDBN} does
11733not yet know how to read. @code{0x@var{nn}} is the symbol type of the
d4f3574e 11734uncomprehended information, in hexadecimal.
c906108c 11735
7a292a7a
SS
11736@value{GDBN} circumvents the error by ignoring this symbol information.
11737This usually allows you to debug your program, though certain symbols
c906108c 11738are not accessible. If you encounter such a problem and feel like
7a292a7a
SS
11739debugging it, you can debug @code{@value{GDBP}} with itself, breakpoint
11740on @code{complain}, then go up to the function @code{read_dbx_symtab}
11741and examine @code{*bufp} to see the symbol.
c906108c
SS
11742
11743@item stub type has NULL name
c906108c 11744
7a292a7a 11745@value{GDBN} could not find the full definition for a struct or class.
c906108c 11746
7a292a7a 11747@item const/volatile indicator missing (ok if using g++ v1.x), got@dots{}
b37052ae 11748The symbol information for a C@t{++} member function is missing some
7a292a7a
SS
11749information that recent versions of the compiler should have output for
11750it.
c906108c
SS
11751
11752@item info mismatch between compiler and debugger
11753
11754@value{GDBN} could not parse a type specification output by the compiler.
7a292a7a 11755
c906108c
SS
11756@end table
11757
6d2ebf8b 11758@node Targets
c906108c 11759@chapter Specifying a Debugging Target
7a292a7a 11760
c906108c 11761@cindex debugging target
c906108c 11762A @dfn{target} is the execution environment occupied by your program.
53a5351d
JM
11763
11764Often, @value{GDBN} runs in the same host environment as your program;
11765in that case, the debugging target is specified as a side effect when
11766you use the @code{file} or @code{core} commands. When you need more
c906108c
SS
11767flexibility---for example, running @value{GDBN} on a physically separate
11768host, or controlling a standalone system over a serial port or a
53a5351d
JM
11769realtime system over a TCP/IP connection---you can use the @code{target}
11770command to specify one of the target types configured for @value{GDBN}
11771(@pxref{Target Commands, ,Commands for managing targets}).
c906108c 11772
a8f24a35
EZ
11773@cindex target architecture
11774It is possible to build @value{GDBN} for several different @dfn{target
11775architectures}. When @value{GDBN} is built like that, you can choose
11776one of the available architectures with the @kbd{set architecture}
11777command.
11778
11779@table @code
11780@kindex set architecture
11781@kindex show architecture
11782@item set architecture @var{arch}
11783This command sets the current target architecture to @var{arch}. The
11784value of @var{arch} can be @code{"auto"}, in addition to one of the
11785supported architectures.
11786
11787@item show architecture
11788Show the current target architecture.
9c16f35a
EZ
11789
11790@item set processor
11791@itemx processor
11792@kindex set processor
11793@kindex show processor
11794These are alias commands for, respectively, @code{set architecture}
11795and @code{show architecture}.
a8f24a35
EZ
11796@end table
11797
c906108c
SS
11798@menu
11799* Active Targets:: Active targets
11800* Target Commands:: Commands for managing targets
c906108c
SS
11801* Byte Order:: Choosing target byte order
11802* Remote:: Remote debugging
96baa820 11803* KOD:: Kernel Object Display
c906108c
SS
11804
11805@end menu
11806
6d2ebf8b 11807@node Active Targets
c906108c 11808@section Active targets
7a292a7a 11809
c906108c
SS
11810@cindex stacking targets
11811@cindex active targets
11812@cindex multiple targets
11813
c906108c 11814There are three classes of targets: processes, core files, and
7a292a7a
SS
11815executable files. @value{GDBN} can work concurrently on up to three
11816active targets, one in each class. This allows you to (for example)
11817start a process and inspect its activity without abandoning your work on
11818a core file.
c906108c
SS
11819
11820For example, if you execute @samp{gdb a.out}, then the executable file
11821@code{a.out} is the only active target. If you designate a core file as
11822well---presumably from a prior run that crashed and coredumped---then
11823@value{GDBN} has two active targets and uses them in tandem, looking
11824first in the corefile target, then in the executable file, to satisfy
11825requests for memory addresses. (Typically, these two classes of target
11826are complementary, since core files contain only a program's
11827read-write memory---variables and so on---plus machine status, while
11828executable files contain only the program text and initialized data.)
c906108c
SS
11829
11830When you type @code{run}, your executable file becomes an active process
7a292a7a
SS
11831target as well. When a process target is active, all @value{GDBN}
11832commands requesting memory addresses refer to that target; addresses in
11833an active core file or executable file target are obscured while the
11834process target is active.
c906108c 11835
7a292a7a
SS
11836Use the @code{core-file} and @code{exec-file} commands to select a new
11837core file or executable target (@pxref{Files, ,Commands to specify
c906108c 11838files}). To specify as a target a process that is already running, use
7a292a7a
SS
11839the @code{attach} command (@pxref{Attach, ,Debugging an already-running
11840process}).
c906108c 11841
6d2ebf8b 11842@node Target Commands
c906108c
SS
11843@section Commands for managing targets
11844
11845@table @code
11846@item target @var{type} @var{parameters}
7a292a7a
SS
11847Connects the @value{GDBN} host environment to a target machine or
11848process. A target is typically a protocol for talking to debugging
11849facilities. You use the argument @var{type} to specify the type or
11850protocol of the target machine.
c906108c
SS
11851
11852Further @var{parameters} are interpreted by the target protocol, but
11853typically include things like device names or host names to connect
11854with, process numbers, and baud rates.
c906108c
SS
11855
11856The @code{target} command does not repeat if you press @key{RET} again
11857after executing the command.
11858
11859@kindex help target
11860@item help target
11861Displays the names of all targets available. To display targets
11862currently selected, use either @code{info target} or @code{info files}
11863(@pxref{Files, ,Commands to specify files}).
11864
11865@item help target @var{name}
11866Describe a particular target, including any parameters necessary to
11867select it.
11868
11869@kindex set gnutarget
11870@item set gnutarget @var{args}
5d161b24 11871@value{GDBN} uses its own library BFD to read your files. @value{GDBN}
c906108c 11872knows whether it is reading an @dfn{executable},
5d161b24
DB
11873a @dfn{core}, or a @dfn{.o} file; however, you can specify the file format
11874with the @code{set gnutarget} command. Unlike most @code{target} commands,
c906108c
SS
11875with @code{gnutarget} the @code{target} refers to a program, not a machine.
11876
d4f3574e 11877@quotation
c906108c
SS
11878@emph{Warning:} To specify a file format with @code{set gnutarget},
11879you must know the actual BFD name.
d4f3574e 11880@end quotation
c906108c 11881
d4f3574e
SS
11882@noindent
11883@xref{Files, , Commands to specify files}.
c906108c 11884
5d161b24 11885@kindex show gnutarget
c906108c
SS
11886@item show gnutarget
11887Use the @code{show gnutarget} command to display what file format
11888@code{gnutarget} is set to read. If you have not set @code{gnutarget},
11889@value{GDBN} will determine the file format for each file automatically,
11890and @code{show gnutarget} displays @samp{The current BDF target is "auto"}.
11891@end table
11892
4644b6e3 11893@cindex common targets
c906108c
SS
11894Here are some common targets (available, or not, depending on the GDB
11895configuration):
c906108c
SS
11896
11897@table @code
4644b6e3 11898@kindex target
c906108c 11899@item target exec @var{program}
4644b6e3 11900@cindex executable file target
c906108c
SS
11901An executable file. @samp{target exec @var{program}} is the same as
11902@samp{exec-file @var{program}}.
11903
c906108c 11904@item target core @var{filename}
4644b6e3 11905@cindex core dump file target
c906108c
SS
11906A core dump file. @samp{target core @var{filename}} is the same as
11907@samp{core-file @var{filename}}.
c906108c 11908
1a10341b 11909@item target remote @var{medium}
4644b6e3 11910@cindex remote target
1a10341b
JB
11911A remote system connected to @value{GDBN} via a serial line or network
11912connection. This command tells @value{GDBN} to use its own remote
11913protocol over @var{medium} for debugging. @xref{Remote Debugging}.
11914
11915For example, if you have a board connected to @file{/dev/ttya} on the
11916machine running @value{GDBN}, you could say:
11917
11918@smallexample
11919target remote /dev/ttya
11920@end smallexample
11921
11922@code{target remote} supports the @code{load} command. This is only
11923useful if you have some other way of getting the stub to the target
11924system, and you can put it somewhere in memory where it won't get
11925clobbered by the download.
c906108c 11926
c906108c 11927@item target sim
4644b6e3 11928@cindex built-in simulator target
2df3850c 11929Builtin CPU simulator. @value{GDBN} includes simulators for most architectures.
104c1213 11930In general,
474c8240 11931@smallexample
104c1213
JM
11932 target sim
11933 load
11934 run
474c8240 11935@end smallexample
d4f3574e 11936@noindent
104c1213 11937works; however, you cannot assume that a specific memory map, device
d4f3574e 11938drivers, or even basic I/O is available, although some simulators do
104c1213
JM
11939provide these. For info about any processor-specific simulator details,
11940see the appropriate section in @ref{Embedded Processors, ,Embedded
11941Processors}.
11942
c906108c
SS
11943@end table
11944
104c1213 11945Some configurations may include these targets as well:
c906108c
SS
11946
11947@table @code
11948
c906108c 11949@item target nrom @var{dev}
4644b6e3 11950@cindex NetROM ROM emulator target
c906108c
SS
11951NetROM ROM emulator. This target only supports downloading.
11952
c906108c
SS
11953@end table
11954
5d161b24 11955Different targets are available on different configurations of @value{GDBN};
c906108c 11956your configuration may have more or fewer targets.
c906108c 11957
721c2651
EZ
11958Many remote targets require you to download the executable's code once
11959you've successfully established a connection. You may wish to control
11960various aspects of this process, such as the size of the data chunks
11961used by @value{GDBN} to download program parts to the remote target.
a8f24a35
EZ
11962
11963@table @code
11964@kindex set download-write-size
11965@item set download-write-size @var{size}
11966Set the write size used when downloading a program. Only used when
11967downloading a program onto a remote target. Specify zero or a
11968negative value to disable blocked writes. The actual size of each
11969transfer is also limited by the size of the target packet and the
11970memory cache.
11971
11972@kindex show download-write-size
11973@item show download-write-size
721c2651 11974@kindex show download-write-size
a8f24a35 11975Show the current value of the write size.
721c2651
EZ
11976
11977@item set hash
11978@kindex set hash@r{, for remote monitors}
11979@cindex hash mark while downloading
11980This command controls whether a hash mark @samp{#} is displayed while
11981downloading a file to the remote monitor. If on, a hash mark is
11982displayed after each S-record is successfully downloaded to the
11983monitor.
11984
11985@item show hash
11986@kindex show hash@r{, for remote monitors}
11987Show the current status of displaying the hash mark.
11988
11989@item set debug monitor
11990@kindex set debug monitor
11991@cindex display remote monitor communications
11992Enable or disable display of communications messages between
11993@value{GDBN} and the remote monitor.
11994
11995@item show debug monitor
11996@kindex show debug monitor
11997Show the current status of displaying communications between
11998@value{GDBN} and the remote monitor.
a8f24a35 11999@end table
c906108c
SS
12000
12001@table @code
12002
12003@kindex load @var{filename}
12004@item load @var{filename}
c906108c
SS
12005Depending on what remote debugging facilities are configured into
12006@value{GDBN}, the @code{load} command may be available. Where it exists, it
12007is meant to make @var{filename} (an executable) available for debugging
12008on the remote system---by downloading, or dynamic linking, for example.
12009@code{load} also records the @var{filename} symbol table in @value{GDBN}, like
12010the @code{add-symbol-file} command.
12011
12012If your @value{GDBN} does not have a @code{load} command, attempting to
12013execute it gets the error message ``@code{You can't do that when your
12014target is @dots{}}''
c906108c
SS
12015
12016The file is loaded at whatever address is specified in the executable.
12017For some object file formats, you can specify the load address when you
12018link the program; for other formats, like a.out, the object file format
12019specifies a fixed address.
12020@c FIXME! This would be a good place for an xref to the GNU linker doc.
12021
c906108c
SS
12022@code{load} does not repeat if you press @key{RET} again after using it.
12023@end table
12024
6d2ebf8b 12025@node Byte Order
c906108c 12026@section Choosing target byte order
7a292a7a 12027
c906108c
SS
12028@cindex choosing target byte order
12029@cindex target byte order
c906108c 12030
172c2a43 12031Some types of processors, such as the MIPS, PowerPC, and Renesas SH,
c906108c
SS
12032offer the ability to run either big-endian or little-endian byte
12033orders. Usually the executable or symbol will include a bit to
12034designate the endian-ness, and you will not need to worry about
12035which to use. However, you may still find it useful to adjust
d4f3574e 12036@value{GDBN}'s idea of processor endian-ness manually.
c906108c
SS
12037
12038@table @code
4644b6e3 12039@kindex set endian
c906108c
SS
12040@item set endian big
12041Instruct @value{GDBN} to assume the target is big-endian.
12042
c906108c
SS
12043@item set endian little
12044Instruct @value{GDBN} to assume the target is little-endian.
12045
c906108c
SS
12046@item set endian auto
12047Instruct @value{GDBN} to use the byte order associated with the
12048executable.
12049
12050@item show endian
12051Display @value{GDBN}'s current idea of the target byte order.
12052
12053@end table
12054
12055Note that these commands merely adjust interpretation of symbolic
12056data on the host, and that they have absolutely no effect on the
12057target system.
12058
6d2ebf8b 12059@node Remote
c906108c
SS
12060@section Remote debugging
12061@cindex remote debugging
12062
12063If you are trying to debug a program running on a machine that cannot run
5d161b24
DB
12064@value{GDBN} in the usual way, it is often useful to use remote debugging.
12065For example, you might use remote debugging on an operating system kernel,
c906108c
SS
12066or on a small system which does not have a general purpose operating system
12067powerful enough to run a full-featured debugger.
12068
12069Some configurations of @value{GDBN} have special serial or TCP/IP interfaces
12070to make this work with particular debugging targets. In addition,
5d161b24 12071@value{GDBN} comes with a generic serial protocol (specific to @value{GDBN},
c906108c
SS
12072but not specific to any particular target system) which you can use if you
12073write the remote stubs---the code that runs on the remote system to
12074communicate with @value{GDBN}.
12075
12076Other remote targets may be available in your
12077configuration of @value{GDBN}; use @code{help target} to list them.
c906108c 12078
c45da7e6
EZ
12079Once you've connected to the remote target, @value{GDBN} allows you to
12080send arbitrary commands to the remote monitor:
12081
12082@table @code
12083@item remote @var{command}
12084@kindex remote@r{, a command}
12085@cindex send command to remote monitor
12086Send an arbitrary @var{command} string to the remote monitor.
12087@end table
12088
12089
6f05cf9f
AC
12090@node KOD
12091@section Kernel Object Display
6f05cf9f 12092@cindex kernel object display
6f05cf9f
AC
12093@cindex KOD
12094
12095Some targets support kernel object display. Using this facility,
12096@value{GDBN} communicates specially with the underlying operating system
12097and can display information about operating system-level objects such as
12098mutexes and other synchronization objects. Exactly which objects can be
12099displayed is determined on a per-OS basis.
12100
3bbe9696 12101@kindex set os
6f05cf9f
AC
12102Use the @code{set os} command to set the operating system. This tells
12103@value{GDBN} which kernel object display module to initialize:
12104
474c8240 12105@smallexample
6f05cf9f 12106(@value{GDBP}) set os cisco
474c8240 12107@end smallexample
6f05cf9f 12108
3bbe9696
EZ
12109@kindex show os
12110The associated command @code{show os} displays the operating system
12111set with the @code{set os} command; if no operating system has been
12112set, @code{show os} will display an empty string @samp{""}.
12113
6f05cf9f
AC
12114If @code{set os} succeeds, @value{GDBN} will display some information
12115about the operating system, and will create a new @code{info} command
12116which can be used to query the target. The @code{info} command is named
12117after the operating system:
c906108c 12118
3bbe9696 12119@kindex info cisco
474c8240 12120@smallexample
6f05cf9f
AC
12121(@value{GDBP}) info cisco
12122List of Cisco Kernel Objects
12123Object Description
12124any Any and all objects
474c8240 12125@end smallexample
6f05cf9f
AC
12126
12127Further subcommands can be used to query about particular objects known
12128by the kernel.
12129
3bbe9696
EZ
12130There is currently no way to determine whether a given operating
12131system is supported other than to try setting it with @kbd{set os
12132@var{name}}, where @var{name} is the name of the operating system you
12133want to try.
6f05cf9f
AC
12134
12135
12136@node Remote Debugging
12137@chapter Debugging remote programs
12138
6b2f586d 12139@menu
07f31aa6 12140* Connecting:: Connecting to a remote target
6b2f586d 12141* Server:: Using the gdbserver program
501eef12 12142* Remote configuration:: Remote configuration
6b2f586d 12143* remote stub:: Implementing a remote stub
6b2f586d
AC
12144@end menu
12145
07f31aa6
DJ
12146@node Connecting
12147@section Connecting to a remote target
12148
12149On the @value{GDBN} host machine, you will need an unstripped copy of
12150your program, since @value{GDBN} needs symobl and debugging information.
12151Start up @value{GDBN} as usual, using the name of the local copy of your
12152program as the first argument.
12153
86941c27
JB
12154@cindex @code{target remote}
12155@value{GDBN} can communicate with the target over a serial line, or
12156over an @acronym{IP} network using @acronym{TCP} or @acronym{UDP}. In
12157each case, @value{GDBN} uses the same protocol for debugging your
12158program; only the medium carrying the debugging packets varies. The
12159@code{target remote} command establishes a connection to the target.
12160Its arguments indicate which medium to use:
12161
12162@table @code
12163
12164@item target remote @var{serial-device}
07f31aa6 12165@cindex serial line, @code{target remote}
86941c27
JB
12166Use @var{serial-device} to communicate with the target. For example,
12167to use a serial line connected to the device named @file{/dev/ttyb}:
12168
12169@smallexample
12170target remote /dev/ttyb
12171@end smallexample
12172
07f31aa6
DJ
12173If you're using a serial line, you may want to give @value{GDBN} the
12174@w{@samp{--baud}} option, or use the @code{set remotebaud} command
9c16f35a
EZ
12175(@pxref{Remote configuration, set remotebaud}) before the
12176@code{target} command.
07f31aa6 12177
86941c27
JB
12178@item target remote @code{@var{host}:@var{port}}
12179@itemx target remote @code{tcp:@var{host}:@var{port}}
12180@cindex @acronym{TCP} port, @code{target remote}
12181Debug using a @acronym{TCP} connection to @var{port} on @var{host}.
12182The @var{host} may be either a host name or a numeric @acronym{IP}
12183address; @var{port} must be a decimal number. The @var{host} could be
12184the target machine itself, if it is directly connected to the net, or
12185it might be a terminal server which in turn has a serial line to the
12186target.
07f31aa6 12187
86941c27
JB
12188For example, to connect to port 2828 on a terminal server named
12189@code{manyfarms}:
07f31aa6
DJ
12190
12191@smallexample
12192target remote manyfarms:2828
12193@end smallexample
12194
86941c27
JB
12195If your remote target is actually running on the same machine as your
12196debugger session (e.g.@: a simulator for your target running on the
12197same host), you can omit the hostname. For example, to connect to
12198port 1234 on your local machine:
07f31aa6
DJ
12199
12200@smallexample
12201target remote :1234
12202@end smallexample
12203@noindent
12204
12205Note that the colon is still required here.
12206
86941c27
JB
12207@item target remote @code{udp:@var{host}:@var{port}}
12208@cindex @acronym{UDP} port, @code{target remote}
12209Debug using @acronym{UDP} packets to @var{port} on @var{host}. For example, to
12210connect to @acronym{UDP} port 2828 on a terminal server named @code{manyfarms}:
07f31aa6
DJ
12211
12212@smallexample
12213target remote udp:manyfarms:2828
12214@end smallexample
12215
86941c27
JB
12216When using a @acronym{UDP} connection for remote debugging, you should
12217keep in mind that the `U' stands for ``Unreliable''. @acronym{UDP}
12218can silently drop packets on busy or unreliable networks, which will
12219cause havoc with your debugging session.
12220
66b8c7f6
JB
12221@item target remote | @var{command}
12222@cindex pipe, @code{target remote} to
12223Run @var{command} in the background and communicate with it using a
12224pipe. The @var{command} is a shell command, to be parsed and expanded
12225by the system's command shell, @code{/bin/sh}; it should expect remote
12226protocol packets on its standard input, and send replies on its
12227standard output. You could use this to run a stand-alone simulator
12228that speaks the remote debugging protocol, to make net connections
12229using programs like @code{ssh}, or for other similar tricks.
12230
12231If @var{command} closes its standard output (perhaps by exiting),
12232@value{GDBN} will try to send it a @code{SIGTERM} signal. (If the
12233program has already exited, this will have no effect.)
12234
86941c27 12235@end table
07f31aa6 12236
86941c27
JB
12237Once the connection has been established, you can use all the usual
12238commands to examine and change data and to step and continue the
12239remote program.
07f31aa6
DJ
12240
12241@cindex interrupting remote programs
12242@cindex remote programs, interrupting
12243Whenever @value{GDBN} is waiting for the remote program, if you type the
12244interrupt character (often @key{C-C}), @value{GDBN} attempts to stop the
12245program. This may or may not succeed, depending in part on the hardware
12246and the serial drivers the remote system uses. If you type the
12247interrupt character once again, @value{GDBN} displays this prompt:
12248
12249@smallexample
12250Interrupted while waiting for the program.
12251Give up (and stop debugging it)? (y or n)
12252@end smallexample
12253
12254If you type @kbd{y}, @value{GDBN} abandons the remote debugging session.
12255(If you decide you want to try again later, you can use @samp{target
12256remote} again to connect once more.) If you type @kbd{n}, @value{GDBN}
12257goes back to waiting.
12258
12259@table @code
12260@kindex detach (remote)
12261@item detach
12262When you have finished debugging the remote program, you can use the
12263@code{detach} command to release it from @value{GDBN} control.
12264Detaching from the target normally resumes its execution, but the results
12265will depend on your particular remote stub. After the @code{detach}
12266command, @value{GDBN} is free to connect to another target.
12267
12268@kindex disconnect
12269@item disconnect
12270The @code{disconnect} command behaves like @code{detach}, except that
12271the target is generally not resumed. It will wait for @value{GDBN}
12272(this instance or another one) to connect and continue debugging. After
12273the @code{disconnect} command, @value{GDBN} is again free to connect to
12274another target.
09d4efe1
EZ
12275
12276@cindex send command to remote monitor
fad38dfa
EZ
12277@cindex extend @value{GDBN} for remote targets
12278@cindex add new commands for external monitor
09d4efe1
EZ
12279@kindex monitor
12280@item monitor @var{cmd}
fad38dfa
EZ
12281This command allows you to send arbitrary commands directly to the
12282remote monitor. Since @value{GDBN} doesn't care about the commands it
12283sends like this, this command is the way to extend @value{GDBN}---you
12284can add new commands that only the external monitor will understand
12285and implement.
07f31aa6
DJ
12286@end table
12287
6f05cf9f
AC
12288@node Server
12289@section Using the @code{gdbserver} program
12290
12291@kindex gdbserver
12292@cindex remote connection without stubs
12293@code{gdbserver} is a control program for Unix-like systems, which
12294allows you to connect your program with a remote @value{GDBN} via
12295@code{target remote}---but without linking in the usual debugging stub.
12296
12297@code{gdbserver} is not a complete replacement for the debugging stubs,
12298because it requires essentially the same operating-system facilities
12299that @value{GDBN} itself does. In fact, a system that can run
12300@code{gdbserver} to connect to a remote @value{GDBN} could also run
12301@value{GDBN} locally! @code{gdbserver} is sometimes useful nevertheless,
12302because it is a much smaller program than @value{GDBN} itself. It is
12303also easier to port than all of @value{GDBN}, so you may be able to get
12304started more quickly on a new system by using @code{gdbserver}.
12305Finally, if you develop code for real-time systems, you may find that
12306the tradeoffs involved in real-time operation make it more convenient to
12307do as much development work as possible on another system, for example
12308by cross-compiling. You can use @code{gdbserver} to make a similar
12309choice for debugging.
12310
12311@value{GDBN} and @code{gdbserver} communicate via either a serial line
12312or a TCP connection, using the standard @value{GDBN} remote serial
12313protocol.
12314
12315@table @emph
12316@item On the target machine,
12317you need to have a copy of the program you want to debug.
12318@code{gdbserver} does not need your program's symbol table, so you can
12319strip the program if necessary to save space. @value{GDBN} on the host
12320system does all the symbol handling.
12321
12322To use the server, you must tell it how to communicate with @value{GDBN};
56460a61 12323the name of your program; and the arguments for your program. The usual
6f05cf9f
AC
12324syntax is:
12325
12326@smallexample
12327target> gdbserver @var{comm} @var{program} [ @var{args} @dots{} ]
12328@end smallexample
12329
12330@var{comm} is either a device name (to use a serial line) or a TCP
12331hostname and portnumber. For example, to debug Emacs with the argument
12332@samp{foo.txt} and communicate with @value{GDBN} over the serial port
12333@file{/dev/com1}:
12334
12335@smallexample
12336target> gdbserver /dev/com1 emacs foo.txt
12337@end smallexample
12338
12339@code{gdbserver} waits passively for the host @value{GDBN} to communicate
12340with it.
12341
12342To use a TCP connection instead of a serial line:
12343
12344@smallexample
12345target> gdbserver host:2345 emacs foo.txt
12346@end smallexample
12347
12348The only difference from the previous example is the first argument,
12349specifying that you are communicating with the host @value{GDBN} via
12350TCP. The @samp{host:2345} argument means that @code{gdbserver} is to
12351expect a TCP connection from machine @samp{host} to local TCP port 2345.
12352(Currently, the @samp{host} part is ignored.) You can choose any number
12353you want for the port number as long as it does not conflict with any
12354TCP ports already in use on the target system (for example, @code{23} is
12355reserved for @code{telnet}).@footnote{If you choose a port number that
12356conflicts with another service, @code{gdbserver} prints an error message
12357and exits.} You must use the same port number with the host @value{GDBN}
12358@code{target remote} command.
12359
56460a61
DJ
12360On some targets, @code{gdbserver} can also attach to running programs.
12361This is accomplished via the @code{--attach} argument. The syntax is:
12362
12363@smallexample
12364target> gdbserver @var{comm} --attach @var{pid}
12365@end smallexample
12366
12367@var{pid} is the process ID of a currently running process. It isn't necessary
12368to point @code{gdbserver} at a binary for the running process.
12369
b1fe9455
DJ
12370@pindex pidof
12371@cindex attach to a program by name
12372You can debug processes by name instead of process ID if your target has the
12373@code{pidof} utility:
12374
12375@smallexample
12376target> gdbserver @var{comm} --attach `pidof @var{PROGRAM}`
12377@end smallexample
12378
12379In case more than one copy of @var{PROGRAM} is running, or @var{PROGRAM}
12380has multiple threads, most versions of @code{pidof} support the
12381@code{-s} option to only return the first process ID.
12382
07f31aa6
DJ
12383@item On the host machine,
12384connect to your target (@pxref{Connecting,,Connecting to a remote target}).
6f05cf9f
AC
12385For TCP connections, you must start up @code{gdbserver} prior to using
12386the @code{target remote} command. Otherwise you may get an error whose
12387text depends on the host system, but which usually looks something like
07f31aa6 12388@samp{Connection refused}. You don't need to use the @code{load}
397ca115
EZ
12389command in @value{GDBN} when using @code{gdbserver}, since the program is
12390already on the target. However, if you want to load the symbols (as
12391you normally would), do that with the @code{file} command, and issue
12392it @emph{before} connecting to the server; otherwise, you will get an
12393error message saying @code{"Program is already running"}, since the
12394program is considered running after the connection.
07f31aa6 12395
6f05cf9f
AC
12396@end table
12397
501eef12
AC
12398@node Remote configuration
12399@section Remote configuration
12400
9c16f35a
EZ
12401@kindex set remote
12402@kindex show remote
12403This section documents the configuration options available when
12404debugging remote programs. For the options related to the File I/O
12405extensions of the remote protocol, see @ref{The system call,
12406system-call-allowed}.
501eef12
AC
12407
12408@table @code
9c16f35a
EZ
12409@item set remoteaddresssize @var{bits}
12410@cindex adress size for remote targets
12411@cindex bits in remote address
12412Set the maximum size of address in a memory packet to the specified
12413number of bits. @value{GDBN} will mask off the address bits above
12414that number, when it passes addresses to the remote target. The
12415default value is the number of bits in the target's address.
12416
12417@item show remoteaddresssize
12418Show the current value of remote address size in bits.
12419
12420@item set remotebaud @var{n}
12421@cindex baud rate for remote targets
12422Set the baud rate for the remote serial I/O to @var{n} baud. The
12423value is used to set the speed of the serial port used for debugging
12424remote targets.
12425
12426@item show remotebaud
12427Show the current speed of the remote connection.
12428
12429@item set remotebreak
12430@cindex interrupt remote programs
12431@cindex BREAK signal instead of Ctrl-C
9a6253be 12432@anchor{set remotebreak}
9c16f35a
EZ
12433If set to on, @value{GDBN} sends a @code{BREAK} signal to the remote
12434when you press the @key{Ctrl-C} key to interrupt the program running
9a7a1b36 12435on the remote. If set to off, @value{GDBN} sends the @samp{Ctrl-C}
9c16f35a
EZ
12436character instead. The default is off, since most remote systems
12437expect to see @samp{Ctrl-C} as the interrupt signal.
12438
12439@item show remotebreak
12440Show whether @value{GDBN} sends @code{BREAK} or @samp{Ctrl-C} to
12441interrupt the remote program.
12442
12443@item set remotedebug
12444@cindex debug remote protocol
12445@cindex remote protocol debugging
12446@cindex display remote packets
12447Control the debugging of the remote protocol. When enabled, each
12448packet sent to or received from the remote target is displayed. The
12449defaults is off.
12450
12451@item show remotedebug
12452Show the current setting of the remote protocol debugging.
12453
12454@item set remotedevice @var{device}
12455@cindex serial port name
12456Set the name of the serial port through which to communicate to the
12457remote target to @var{device}. This is the device used by
12458@value{GDBN} to open the serial communications line to the remote
12459target. There's no default, so you must set a valid port name for the
12460remote serial communications to work. (Some varieties of the
12461@code{target} command accept the port name as part of their
12462arguments.)
12463
12464@item show remotedevice
12465Show the current name of the serial port.
12466
12467@item set remotelogbase @var{base}
12468Set the base (a.k.a.@: radix) of logging serial protocol
12469communications to @var{base}. Supported values of @var{base} are:
12470@code{ascii}, @code{octal}, and @code{hex}. The default is
12471@code{ascii}.
12472
12473@item show remotelogbase
12474Show the current setting of the radix for logging remote serial
12475protocol.
12476
12477@item set remotelogfile @var{file}
12478@cindex record serial communications on file
12479Record remote serial communications on the named @var{file}. The
12480default is not to record at all.
12481
12482@item show remotelogfile.
12483Show the current setting of the file name on which to record the
12484serial communications.
12485
12486@item set remotetimeout @var{num}
12487@cindex timeout for serial communications
12488@cindex remote timeout
12489Set the timeout limit to wait for the remote target to respond to
12490@var{num} seconds. The default is 2 seconds.
12491
12492@item show remotetimeout
12493Show the current number of seconds to wait for the remote target
12494responses.
12495
12496@cindex limit hardware breakpoints and watchpoints
12497@cindex remote target, limit break- and watchpoints
501eef12
AC
12498@anchor{set remote hardware-watchpoint-limit}
12499@anchor{set remote hardware-breakpoint-limit}
12500@item set remote hardware-watchpoint-limit @var{limit}
12501@itemx set remote hardware-breakpoint-limit @var{limit}
12502Restrict @value{GDBN} to using @var{limit} remote hardware breakpoint or
12503watchpoints. A limit of -1, the default, is treated as unlimited.
9c16f35a
EZ
12504
12505@item set remote fetch-register-packet
12506@itemx set remote set-register-packet
12507@itemx set remote P-packet
12508@itemx set remote p-packet
12509@cindex P-packet
12510@cindex fetch registers from remote targets
12511@cindex set registers in remote targets
12512Determine whether @value{GDBN} can set and fetch registers from the
12513remote target using the @samp{P} packets. The default depends on the
12514remote stub's support of the @samp{P} packets (@value{GDBN} queries
12515the stub when this packet is first required).
12516
12517@item show remote fetch-register-packet
12518@itemx show remote set-register-packet
12519@itemx show remote P-packet
12520@itemx show remote p-packet
12521Show the current setting of using the @samp{P} packets for setting and
12522fetching registers from the remote target.
12523
12524@cindex binary downloads
12525@cindex X-packet
12526@item set remote binary-download-packet
12527@itemx set remote X-packet
12528Determine whether @value{GDBN} sends downloads in binary mode using
12529the @samp{X} packets. The default is on.
12530
12531@item show remote binary-download-packet
12532@itemx show remote X-packet
12533Show the current setting of using the @samp{X} packets for binary
12534downloads.
12535
12536@item set remote read-aux-vector-packet
12537@cindex auxiliary vector of remote target
12538@cindex @code{auxv}, and remote targets
12539Set the use of the remote protocol's @samp{qPart:auxv:read} (target
12540auxiliary vector read) request. This request is used to fetch the
721c2651
EZ
12541remote target's @dfn{auxiliary vector}, see @ref{OS Information,
12542Auxiliary Vector}. The default setting depends on the remote stub's
12543support of this request (@value{GDBN} queries the stub when this
12544request is first required). @xref{General Query Packets, qPart}, for
12545more information about this request.
9c16f35a
EZ
12546
12547@item show remote read-aux-vector-packet
12548Show the current setting of use of the @samp{qPart:auxv:read} request.
12549
12550@item set remote symbol-lookup-packet
12551@cindex remote symbol lookup request
12552Set the use of the remote protocol's @samp{qSymbol} (target symbol
12553lookup) request. This request is used to communicate symbol
12554information to the remote target, e.g., whenever a new shared library
12555is loaded by the remote (@pxref{Files, shared libraries}). The
12556default setting depends on the remote stub's support of this request
12557(@value{GDBN} queries the stub when this request is first required).
12558@xref{General Query Packets, qSymbol}, for more information about this
12559request.
12560
12561@item show remote symbol-lookup-packet
12562Show the current setting of use of the @samp{qSymbol} request.
12563
12564@item set remote verbose-resume-packet
12565@cindex resume remote target
12566@cindex signal thread, and remote targets
12567@cindex single-step thread, and remote targets
12568@cindex thread-specific operations on remote targets
12569Set the use of the remote protocol's @samp{vCont} (descriptive resume)
12570request. This request is used to resume specific threads in the
12571remote target, and to single-step or signal them. The default setting
12572depends on the remote stub's support of this request (@value{GDBN}
12573queries the stub when this request is first required). This setting
12574affects debugging of multithreaded programs: if @samp{vCont} cannot be
12575used, @value{GDBN} might be unable to single-step a specific thread,
12576especially under @code{set scheduler-locking off}; it is also
12577impossible to pause a specific thread. @xref{Packets, vCont}, for
12578more details.
12579
12580@item show remote verbose-resume-packet
12581Show the current setting of use of the @samp{vCont} request
12582
12583@item set remote software-breakpoint-packet
12584@itemx set remote hardware-breakpoint-packet
12585@itemx set remote write-watchpoint-packet
12586@itemx set remote read-watchpoint-packet
12587@itemx set remote access-watchpoint-packet
12588@itemx set remote Z-packet
12589@cindex Z-packet
12590@cindex remote hardware breakpoints and watchpoints
12591These commands enable or disable the use of @samp{Z} packets for
12592setting breakpoints and watchpoints in the remote target. The default
12593depends on the remote stub's support of the @samp{Z} packets
12594(@value{GDBN} queries the stub when each packet is first required).
12595The command @code{set remote Z-packet}, kept for back-compatibility,
12596turns on or off all the features that require the use of @samp{Z}
12597packets.
12598
12599@item show remote software-breakpoint-packet
12600@itemx show remote hardware-breakpoint-packet
12601@itemx show remote write-watchpoint-packet
12602@itemx show remote read-watchpoint-packet
12603@itemx show remote access-watchpoint-packet
12604@itemx show remote Z-packet
12605Show the current setting of @samp{Z} packets usage.
0abb7bc7
EZ
12606
12607@item set remote get-thread-local-storage-address
12608@kindex set remote get-thread-local-storage-address
12609@cindex thread local storage of remote targets
12610This command enables or disables the use of the @samp{qGetTLSAddr}
12611(Get Thread Local Storage Address) request packet. The default
12612depends on whether the remote stub supports this request.
12613@xref{General Query Packets, qGetTLSAddr}, for more details about this
12614packet.
12615
12616@item show remote get-thread-local-storage-address
12617@kindex show remote get-thread-local-storage-address
12618Show the current setting of @samp{qGetTLSAddr} packet usage.
501eef12
AC
12619@end table
12620
6f05cf9f
AC
12621@node remote stub
12622@section Implementing a remote stub
7a292a7a 12623
8e04817f
AC
12624@cindex debugging stub, example
12625@cindex remote stub, example
12626@cindex stub example, remote debugging
12627The stub files provided with @value{GDBN} implement the target side of the
12628communication protocol, and the @value{GDBN} side is implemented in the
12629@value{GDBN} source file @file{remote.c}. Normally, you can simply allow
12630these subroutines to communicate, and ignore the details. (If you're
12631implementing your own stub file, you can still ignore the details: start
12632with one of the existing stub files. @file{sparc-stub.c} is the best
12633organized, and therefore the easiest to read.)
12634
104c1213
JM
12635@cindex remote serial debugging, overview
12636To debug a program running on another machine (the debugging
12637@dfn{target} machine), you must first arrange for all the usual
12638prerequisites for the program to run by itself. For example, for a C
12639program, you need:
c906108c 12640
104c1213
JM
12641@enumerate
12642@item
12643A startup routine to set up the C runtime environment; these usually
12644have a name like @file{crt0}. The startup routine may be supplied by
12645your hardware supplier, or you may have to write your own.
96baa820 12646
5d161b24 12647@item
d4f3574e 12648A C subroutine library to support your program's
104c1213 12649subroutine calls, notably managing input and output.
96baa820 12650
104c1213
JM
12651@item
12652A way of getting your program to the other machine---for example, a
12653download program. These are often supplied by the hardware
12654manufacturer, but you may have to write your own from hardware
12655documentation.
12656@end enumerate
96baa820 12657
104c1213
JM
12658The next step is to arrange for your program to use a serial port to
12659communicate with the machine where @value{GDBN} is running (the @dfn{host}
12660machine). In general terms, the scheme looks like this:
96baa820 12661
104c1213
JM
12662@table @emph
12663@item On the host,
12664@value{GDBN} already understands how to use this protocol; when everything
12665else is set up, you can simply use the @samp{target remote} command
12666(@pxref{Targets,,Specifying a Debugging Target}).
12667
12668@item On the target,
12669you must link with your program a few special-purpose subroutines that
12670implement the @value{GDBN} remote serial protocol. The file containing these
12671subroutines is called a @dfn{debugging stub}.
12672
12673On certain remote targets, you can use an auxiliary program
12674@code{gdbserver} instead of linking a stub into your program.
12675@xref{Server,,Using the @code{gdbserver} program}, for details.
12676@end table
96baa820 12677
104c1213
JM
12678The debugging stub is specific to the architecture of the remote
12679machine; for example, use @file{sparc-stub.c} to debug programs on
12680@sc{sparc} boards.
96baa820 12681
104c1213
JM
12682@cindex remote serial stub list
12683These working remote stubs are distributed with @value{GDBN}:
96baa820 12684
104c1213
JM
12685@table @code
12686
12687@item i386-stub.c
41afff9a 12688@cindex @file{i386-stub.c}
104c1213
JM
12689@cindex Intel
12690@cindex i386
12691For Intel 386 and compatible architectures.
12692
12693@item m68k-stub.c
41afff9a 12694@cindex @file{m68k-stub.c}
104c1213
JM
12695@cindex Motorola 680x0
12696@cindex m680x0
12697For Motorola 680x0 architectures.
12698
12699@item sh-stub.c
41afff9a 12700@cindex @file{sh-stub.c}
172c2a43 12701@cindex Renesas
104c1213 12702@cindex SH
172c2a43 12703For Renesas SH architectures.
104c1213
JM
12704
12705@item sparc-stub.c
41afff9a 12706@cindex @file{sparc-stub.c}
104c1213
JM
12707@cindex Sparc
12708For @sc{sparc} architectures.
12709
12710@item sparcl-stub.c
41afff9a 12711@cindex @file{sparcl-stub.c}
104c1213
JM
12712@cindex Fujitsu
12713@cindex SparcLite
12714For Fujitsu @sc{sparclite} architectures.
12715
12716@end table
12717
12718The @file{README} file in the @value{GDBN} distribution may list other
12719recently added stubs.
12720
12721@menu
12722* Stub Contents:: What the stub can do for you
12723* Bootstrapping:: What you must do for the stub
12724* Debug Session:: Putting it all together
104c1213
JM
12725@end menu
12726
6d2ebf8b 12727@node Stub Contents
6f05cf9f 12728@subsection What the stub can do for you
104c1213
JM
12729
12730@cindex remote serial stub
12731The debugging stub for your architecture supplies these three
12732subroutines:
12733
12734@table @code
12735@item set_debug_traps
4644b6e3 12736@findex set_debug_traps
104c1213
JM
12737@cindex remote serial stub, initialization
12738This routine arranges for @code{handle_exception} to run when your
12739program stops. You must call this subroutine explicitly near the
12740beginning of your program.
12741
12742@item handle_exception
4644b6e3 12743@findex handle_exception
104c1213
JM
12744@cindex remote serial stub, main routine
12745This is the central workhorse, but your program never calls it
12746explicitly---the setup code arranges for @code{handle_exception} to
12747run when a trap is triggered.
12748
12749@code{handle_exception} takes control when your program stops during
12750execution (for example, on a breakpoint), and mediates communications
12751with @value{GDBN} on the host machine. This is where the communications
12752protocol is implemented; @code{handle_exception} acts as the @value{GDBN}
d4f3574e 12753representative on the target machine. It begins by sending summary
104c1213
JM
12754information on the state of your program, then continues to execute,
12755retrieving and transmitting any information @value{GDBN} needs, until you
12756execute a @value{GDBN} command that makes your program resume; at that point,
12757@code{handle_exception} returns control to your own code on the target
5d161b24 12758machine.
104c1213
JM
12759
12760@item breakpoint
12761@cindex @code{breakpoint} subroutine, remote
12762Use this auxiliary subroutine to make your program contain a
12763breakpoint. Depending on the particular situation, this may be the only
12764way for @value{GDBN} to get control. For instance, if your target
12765machine has some sort of interrupt button, you won't need to call this;
12766pressing the interrupt button transfers control to
12767@code{handle_exception}---in effect, to @value{GDBN}. On some machines,
12768simply receiving characters on the serial port may also trigger a trap;
12769again, in that situation, you don't need to call @code{breakpoint} from
12770your own program---simply running @samp{target remote} from the host
5d161b24 12771@value{GDBN} session gets control.
104c1213
JM
12772
12773Call @code{breakpoint} if none of these is true, or if you simply want
12774to make certain your program stops at a predetermined point for the
12775start of your debugging session.
12776@end table
12777
6d2ebf8b 12778@node Bootstrapping
6f05cf9f 12779@subsection What you must do for the stub
104c1213
JM
12780
12781@cindex remote stub, support routines
12782The debugging stubs that come with @value{GDBN} are set up for a particular
12783chip architecture, but they have no information about the rest of your
12784debugging target machine.
12785
12786First of all you need to tell the stub how to communicate with the
12787serial port.
12788
12789@table @code
12790@item int getDebugChar()
4644b6e3 12791@findex getDebugChar
104c1213
JM
12792Write this subroutine to read a single character from the serial port.
12793It may be identical to @code{getchar} for your target system; a
12794different name is used to allow you to distinguish the two if you wish.
12795
12796@item void putDebugChar(int)
4644b6e3 12797@findex putDebugChar
104c1213 12798Write this subroutine to write a single character to the serial port.
5d161b24 12799It may be identical to @code{putchar} for your target system; a
104c1213
JM
12800different name is used to allow you to distinguish the two if you wish.
12801@end table
12802
12803@cindex control C, and remote debugging
12804@cindex interrupting remote targets
12805If you want @value{GDBN} to be able to stop your program while it is
12806running, you need to use an interrupt-driven serial driver, and arrange
12807for it to stop when it receives a @code{^C} (@samp{\003}, the control-C
12808character). That is the character which @value{GDBN} uses to tell the
12809remote system to stop.
12810
12811Getting the debugging target to return the proper status to @value{GDBN}
12812probably requires changes to the standard stub; one quick and dirty way
12813is to just execute a breakpoint instruction (the ``dirty'' part is that
12814@value{GDBN} reports a @code{SIGTRAP} instead of a @code{SIGINT}).
12815
12816Other routines you need to supply are:
12817
12818@table @code
12819@item void exceptionHandler (int @var{exception_number}, void *@var{exception_address})
4644b6e3 12820@findex exceptionHandler
104c1213
JM
12821Write this function to install @var{exception_address} in the exception
12822handling tables. You need to do this because the stub does not have any
12823way of knowing what the exception handling tables on your target system
12824are like (for example, the processor's table might be in @sc{rom},
12825containing entries which point to a table in @sc{ram}).
12826@var{exception_number} is the exception number which should be changed;
12827its meaning is architecture-dependent (for example, different numbers
12828might represent divide by zero, misaligned access, etc). When this
12829exception occurs, control should be transferred directly to
12830@var{exception_address}, and the processor state (stack, registers,
12831and so on) should be just as it is when a processor exception occurs. So if
12832you want to use a jump instruction to reach @var{exception_address}, it
12833should be a simple jump, not a jump to subroutine.
12834
12835For the 386, @var{exception_address} should be installed as an interrupt
12836gate so that interrupts are masked while the handler runs. The gate
12837should be at privilege level 0 (the most privileged level). The
12838@sc{sparc} and 68k stubs are able to mask interrupts themselves without
12839help from @code{exceptionHandler}.
12840
12841@item void flush_i_cache()
4644b6e3 12842@findex flush_i_cache
d4f3574e 12843On @sc{sparc} and @sc{sparclite} only, write this subroutine to flush the
104c1213
JM
12844instruction cache, if any, on your target machine. If there is no
12845instruction cache, this subroutine may be a no-op.
12846
12847On target machines that have instruction caches, @value{GDBN} requires this
12848function to make certain that the state of your program is stable.
12849@end table
12850
12851@noindent
12852You must also make sure this library routine is available:
12853
12854@table @code
12855@item void *memset(void *, int, int)
4644b6e3 12856@findex memset
104c1213
JM
12857This is the standard library function @code{memset} that sets an area of
12858memory to a known value. If you have one of the free versions of
12859@code{libc.a}, @code{memset} can be found there; otherwise, you must
12860either obtain it from your hardware manufacturer, or write your own.
12861@end table
12862
12863If you do not use the GNU C compiler, you may need other standard
12864library subroutines as well; this varies from one stub to another,
12865but in general the stubs are likely to use any of the common library
d4f3574e 12866subroutines which @code{@value{GCC}} generates as inline code.
104c1213
JM
12867
12868
6d2ebf8b 12869@node Debug Session
6f05cf9f 12870@subsection Putting it all together
104c1213
JM
12871
12872@cindex remote serial debugging summary
12873In summary, when your program is ready to debug, you must follow these
12874steps.
12875
12876@enumerate
12877@item
6d2ebf8b 12878Make sure you have defined the supporting low-level routines
104c1213
JM
12879(@pxref{Bootstrapping,,What you must do for the stub}):
12880@display
12881@code{getDebugChar}, @code{putDebugChar},
12882@code{flush_i_cache}, @code{memset}, @code{exceptionHandler}.
12883@end display
12884
12885@item
12886Insert these lines near the top of your program:
12887
474c8240 12888@smallexample
104c1213
JM
12889set_debug_traps();
12890breakpoint();
474c8240 12891@end smallexample
104c1213
JM
12892
12893@item
12894For the 680x0 stub only, you need to provide a variable called
12895@code{exceptionHook}. Normally you just use:
12896
474c8240 12897@smallexample
104c1213 12898void (*exceptionHook)() = 0;
474c8240 12899@end smallexample
104c1213 12900
d4f3574e 12901@noindent
104c1213 12902but if before calling @code{set_debug_traps}, you set it to point to a
598ca718 12903function in your program, that function is called when
104c1213
JM
12904@code{@value{GDBN}} continues after stopping on a trap (for example, bus
12905error). The function indicated by @code{exceptionHook} is called with
12906one parameter: an @code{int} which is the exception number.
12907
12908@item
12909Compile and link together: your program, the @value{GDBN} debugging stub for
12910your target architecture, and the supporting subroutines.
12911
12912@item
12913Make sure you have a serial connection between your target machine and
12914the @value{GDBN} host, and identify the serial port on the host.
12915
12916@item
12917@c The "remote" target now provides a `load' command, so we should
12918@c document that. FIXME.
12919Download your program to your target machine (or get it there by
12920whatever means the manufacturer provides), and start it.
12921
12922@item
07f31aa6
DJ
12923Start @value{GDBN} on the host, and connect to the target
12924(@pxref{Connecting,,Connecting to a remote target}).
9db8d71f 12925
104c1213
JM
12926@end enumerate
12927
8e04817f
AC
12928@node Configurations
12929@chapter Configuration-Specific Information
104c1213 12930
8e04817f
AC
12931While nearly all @value{GDBN} commands are available for all native and
12932cross versions of the debugger, there are some exceptions. This chapter
12933describes things that are only available in certain configurations.
104c1213 12934
8e04817f
AC
12935There are three major categories of configurations: native
12936configurations, where the host and target are the same, embedded
12937operating system configurations, which are usually the same for several
12938different processor architectures, and bare embedded processors, which
12939are quite different from each other.
104c1213 12940
8e04817f
AC
12941@menu
12942* Native::
12943* Embedded OS::
12944* Embedded Processors::
12945* Architectures::
12946@end menu
104c1213 12947
8e04817f
AC
12948@node Native
12949@section Native
104c1213 12950
8e04817f
AC
12951This section describes details specific to particular native
12952configurations.
6cf7e474 12953
8e04817f
AC
12954@menu
12955* HP-UX:: HP-UX
7561d450 12956* BSD libkvm Interface:: Debugging BSD kernel memory images
8e04817f
AC
12957* SVR4 Process Information:: SVR4 process information
12958* DJGPP Native:: Features specific to the DJGPP port
78c47bea 12959* Cygwin Native:: Features specific to the Cygwin port
14d6dd68 12960* Hurd Native:: Features specific to @sc{gnu} Hurd
a64548ea 12961* Neutrino:: Features specific to QNX Neutrino
8e04817f 12962@end menu
6cf7e474 12963
8e04817f
AC
12964@node HP-UX
12965@subsection HP-UX
104c1213 12966
8e04817f
AC
12967On HP-UX systems, if you refer to a function or variable name that
12968begins with a dollar sign, @value{GDBN} searches for a user or system
12969name first, before it searches for a convenience variable.
104c1213 12970
9c16f35a 12971
7561d450
MK
12972@node BSD libkvm Interface
12973@subsection BSD libkvm Interface
12974
12975@cindex libkvm
12976@cindex kernel memory image
12977@cindex kernel crash dump
12978
12979BSD-derived systems (FreeBSD/NetBSD/OpenBSD) have a kernel memory
12980interface that provides a uniform interface for accessing kernel virtual
12981memory images, including live systems and crash dumps. @value{GDBN}
12982uses this interface to allow you to debug live kernels and kernel crash
12983dumps on many native BSD configurations. This is implemented as a
12984special @code{kvm} debugging target. For debugging a live system, load
12985the currently running kernel into @value{GDBN} and connect to the
12986@code{kvm} target:
12987
12988@smallexample
12989(@value{GDBP}) @b{target kvm}
12990@end smallexample
12991
12992For debugging crash dumps, provide the file name of the crash dump as an
12993argument:
12994
12995@smallexample
12996(@value{GDBP}) @b{target kvm /var/crash/bsd.0}
12997@end smallexample
12998
12999Once connected to the @code{kvm} target, the following commands are
13000available:
13001
13002@table @code
13003@kindex kvm
13004@item kvm pcb
721c2651 13005Set current context from the @dfn{Process Control Block} (PCB) address.
7561d450
MK
13006
13007@item kvm proc
13008Set current context from proc address. This command isn't available on
13009modern FreeBSD systems.
13010@end table
13011
8e04817f
AC
13012@node SVR4 Process Information
13013@subsection SVR4 process information
60bf7e09
EZ
13014@cindex /proc
13015@cindex examine process image
13016@cindex process info via @file{/proc}
104c1213 13017
60bf7e09
EZ
13018Many versions of SVR4 and compatible systems provide a facility called
13019@samp{/proc} that can be used to examine the image of a running
13020process using file-system subroutines. If @value{GDBN} is configured
13021for an operating system with this facility, the command @code{info
13022proc} is available to report information about the process running
13023your program, or about any process running on your system. @code{info
13024proc} works only on SVR4 systems that include the @code{procfs} code.
13025This includes, as of this writing, @sc{gnu}/Linux, OSF/1 (Digital
13026Unix), Solaris, Irix, and Unixware, but not HP-UX, for example.
104c1213 13027
8e04817f
AC
13028@table @code
13029@kindex info proc
60bf7e09 13030@cindex process ID
8e04817f 13031@item info proc
60bf7e09
EZ
13032@itemx info proc @var{process-id}
13033Summarize available information about any running process. If a
13034process ID is specified by @var{process-id}, display information about
13035that process; otherwise display information about the program being
13036debugged. The summary includes the debugged process ID, the command
13037line used to invoke it, its current working directory, and its
13038executable file's absolute file name.
13039
13040On some systems, @var{process-id} can be of the form
13041@samp{[@var{pid}]/@var{tid}} which specifies a certain thread ID
13042within a process. If the optional @var{pid} part is missing, it means
13043a thread from the process being debugged (the leading @samp{/} still
13044needs to be present, or else @value{GDBN} will interpret the number as
13045a process ID rather than a thread ID).
6cf7e474 13046
8e04817f 13047@item info proc mappings
60bf7e09
EZ
13048@cindex memory address space mappings
13049Report the memory address space ranges accessible in the program, with
13050information on whether the process has read, write, or execute access
13051rights to each range. On @sc{gnu}/Linux systems, each memory range
13052includes the object file which is mapped to that range, instead of the
13053memory access rights to that range.
13054
13055@item info proc stat
13056@itemx info proc status
13057@cindex process detailed status information
13058These subcommands are specific to @sc{gnu}/Linux systems. They show
13059the process-related information, including the user ID and group ID;
13060how many threads are there in the process; its virtual memory usage;
13061the signals that are pending, blocked, and ignored; its TTY; its
13062consumption of system and user time; its stack size; its @samp{nice}
2eecc4ab 13063value; etc. For more information, see the @samp{proc} man page
60bf7e09
EZ
13064(type @kbd{man 5 proc} from your shell prompt).
13065
13066@item info proc all
13067Show all the information about the process described under all of the
13068above @code{info proc} subcommands.
13069
8e04817f
AC
13070@ignore
13071@comment These sub-options of 'info proc' were not included when
13072@comment procfs.c was re-written. Keep their descriptions around
13073@comment against the day when someone finds the time to put them back in.
13074@kindex info proc times
13075@item info proc times
13076Starting time, user CPU time, and system CPU time for your program and
13077its children.
6cf7e474 13078
8e04817f
AC
13079@kindex info proc id
13080@item info proc id
13081Report on the process IDs related to your program: its own process ID,
13082the ID of its parent, the process group ID, and the session ID.
8e04817f 13083@end ignore
721c2651
EZ
13084
13085@item set procfs-trace
13086@kindex set procfs-trace
13087@cindex @code{procfs} API calls
13088This command enables and disables tracing of @code{procfs} API calls.
13089
13090@item show procfs-trace
13091@kindex show procfs-trace
13092Show the current state of @code{procfs} API call tracing.
13093
13094@item set procfs-file @var{file}
13095@kindex set procfs-file
13096Tell @value{GDBN} to write @code{procfs} API trace to the named
13097@var{file}. @value{GDBN} appends the trace info to the previous
13098contents of the file. The default is to display the trace on the
13099standard output.
13100
13101@item show procfs-file
13102@kindex show procfs-file
13103Show the file to which @code{procfs} API trace is written.
13104
13105@item proc-trace-entry
13106@itemx proc-trace-exit
13107@itemx proc-untrace-entry
13108@itemx proc-untrace-exit
13109@kindex proc-trace-entry
13110@kindex proc-trace-exit
13111@kindex proc-untrace-entry
13112@kindex proc-untrace-exit
13113These commands enable and disable tracing of entries into and exits
13114from the @code{syscall} interface.
13115
13116@item info pidlist
13117@kindex info pidlist
13118@cindex process list, QNX Neutrino
13119For QNX Neutrino only, this command displays the list of all the
13120processes and all the threads within each process.
13121
13122@item info meminfo
13123@kindex info meminfo
13124@cindex mapinfo list, QNX Neutrino
13125For QNX Neutrino only, this command displays the list of all mapinfos.
8e04817f 13126@end table
104c1213 13127
8e04817f
AC
13128@node DJGPP Native
13129@subsection Features for Debugging @sc{djgpp} Programs
13130@cindex @sc{djgpp} debugging
13131@cindex native @sc{djgpp} debugging
13132@cindex MS-DOS-specific commands
104c1213 13133
514c4d71
EZ
13134@cindex DPMI
13135@sc{djgpp} is a port of the @sc{gnu} development tools to MS-DOS and
8e04817f
AC
13136MS-Windows. @sc{djgpp} programs are 32-bit protected-mode programs
13137that use the @dfn{DPMI} (DOS Protected-Mode Interface) API to run on
13138top of real-mode DOS systems and their emulations.
104c1213 13139
8e04817f
AC
13140@value{GDBN} supports native debugging of @sc{djgpp} programs, and
13141defines a few commands specific to the @sc{djgpp} port. This
13142subsection describes those commands.
104c1213 13143
8e04817f
AC
13144@table @code
13145@kindex info dos
13146@item info dos
13147This is a prefix of @sc{djgpp}-specific commands which print
13148information about the target system and important OS structures.
f1251bdd 13149
8e04817f
AC
13150@kindex sysinfo
13151@cindex MS-DOS system info
13152@cindex free memory information (MS-DOS)
13153@item info dos sysinfo
13154This command displays assorted information about the underlying
13155platform: the CPU type and features, the OS version and flavor, the
13156DPMI version, and the available conventional and DPMI memory.
104c1213 13157
8e04817f
AC
13158@cindex GDT
13159@cindex LDT
13160@cindex IDT
13161@cindex segment descriptor tables
13162@cindex descriptor tables display
13163@item info dos gdt
13164@itemx info dos ldt
13165@itemx info dos idt
13166These 3 commands display entries from, respectively, Global, Local,
13167and Interrupt Descriptor Tables (GDT, LDT, and IDT). The descriptor
13168tables are data structures which store a descriptor for each segment
13169that is currently in use. The segment's selector is an index into a
13170descriptor table; the table entry for that index holds the
13171descriptor's base address and limit, and its attributes and access
13172rights.
104c1213 13173
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AC
13174A typical @sc{djgpp} program uses 3 segments: a code segment, a data
13175segment (used for both data and the stack), and a DOS segment (which
13176allows access to DOS/BIOS data structures and absolute addresses in
13177conventional memory). However, the DPMI host will usually define
13178additional segments in order to support the DPMI environment.
d4f3574e 13179
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AC
13180@cindex garbled pointers
13181These commands allow to display entries from the descriptor tables.
13182Without an argument, all entries from the specified table are
13183displayed. An argument, which should be an integer expression, means
13184display a single entry whose index is given by the argument. For
13185example, here's a convenient way to display information about the
13186debugged program's data segment:
104c1213 13187
8e04817f
AC
13188@smallexample
13189@exdent @code{(@value{GDBP}) info dos ldt $ds}
13190@exdent @code{0x13f: base=0x11970000 limit=0x0009ffff 32-Bit Data (Read/Write, Exp-up)}
13191@end smallexample
104c1213 13192
8e04817f
AC
13193@noindent
13194This comes in handy when you want to see whether a pointer is outside
13195the data segment's limit (i.e.@: @dfn{garbled}).
104c1213 13196
8e04817f
AC
13197@cindex page tables display (MS-DOS)
13198@item info dos pde
13199@itemx info dos pte
13200These two commands display entries from, respectively, the Page
13201Directory and the Page Tables. Page Directories and Page Tables are
13202data structures which control how virtual memory addresses are mapped
13203into physical addresses. A Page Table includes an entry for every
13204page of memory that is mapped into the program's address space; there
13205may be several Page Tables, each one holding up to 4096 entries. A
13206Page Directory has up to 4096 entries, one each for every Page Table
13207that is currently in use.
104c1213 13208
8e04817f
AC
13209Without an argument, @kbd{info dos pde} displays the entire Page
13210Directory, and @kbd{info dos pte} displays all the entries in all of
13211the Page Tables. An argument, an integer expression, given to the
13212@kbd{info dos pde} command means display only that entry from the Page
13213Directory table. An argument given to the @kbd{info dos pte} command
13214means display entries from a single Page Table, the one pointed to by
13215the specified entry in the Page Directory.
104c1213 13216
8e04817f
AC
13217@cindex direct memory access (DMA) on MS-DOS
13218These commands are useful when your program uses @dfn{DMA} (Direct
13219Memory Access), which needs physical addresses to program the DMA
13220controller.
104c1213 13221
8e04817f 13222These commands are supported only with some DPMI servers.
104c1213 13223
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AC
13224@cindex physical address from linear address
13225@item info dos address-pte @var{addr}
13226This command displays the Page Table entry for a specified linear
514c4d71
EZ
13227address. The argument @var{addr} is a linear address which should
13228already have the appropriate segment's base address added to it,
13229because this command accepts addresses which may belong to @emph{any}
13230segment. For example, here's how to display the Page Table entry for
13231the page where a variable @code{i} is stored:
104c1213 13232
b383017d 13233@smallexample
8e04817f
AC
13234@exdent @code{(@value{GDBP}) info dos address-pte __djgpp_base_address + (char *)&i}
13235@exdent @code{Page Table entry for address 0x11a00d30:}
b383017d 13236@exdent @code{Base=0x02698000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0xd30}
8e04817f 13237@end smallexample
104c1213 13238
8e04817f
AC
13239@noindent
13240This says that @code{i} is stored at offset @code{0xd30} from the page
514c4d71 13241whose physical base address is @code{0x02698000}, and shows all the
8e04817f 13242attributes of that page.
104c1213 13243
8e04817f
AC
13244Note that you must cast the addresses of variables to a @code{char *},
13245since otherwise the value of @code{__djgpp_base_address}, the base
13246address of all variables and functions in a @sc{djgpp} program, will
13247be added using the rules of C pointer arithmetics: if @code{i} is
13248declared an @code{int}, @value{GDBN} will add 4 times the value of
13249@code{__djgpp_base_address} to the address of @code{i}.
104c1213 13250
8e04817f
AC
13251Here's another example, it displays the Page Table entry for the
13252transfer buffer:
104c1213 13253
8e04817f
AC
13254@smallexample
13255@exdent @code{(@value{GDBP}) info dos address-pte *((unsigned *)&_go32_info_block + 3)}
13256@exdent @code{Page Table entry for address 0x29110:}
13257@exdent @code{Base=0x00029000 Dirty Acc. Not-Cached Write-Back Usr Read-Write +0x110}
13258@end smallexample
104c1213 13259
8e04817f
AC
13260@noindent
13261(The @code{+ 3} offset is because the transfer buffer's address is the
514c4d71
EZ
132623rd member of the @code{_go32_info_block} structure.) The output
13263clearly shows that this DPMI server maps the addresses in conventional
13264memory 1:1, i.e.@: the physical (@code{0x00029000} + @code{0x110}) and
13265linear (@code{0x29110}) addresses are identical.
104c1213 13266
8e04817f
AC
13267This command is supported only with some DPMI servers.
13268@end table
104c1213 13269
c45da7e6 13270@cindex DOS serial data link, remote debugging
a8f24a35
EZ
13271In addition to native debugging, the DJGPP port supports remote
13272debugging via a serial data link. The following commands are specific
13273to remote serial debugging in the DJGPP port of @value{GDBN}.
13274
13275@table @code
13276@kindex set com1base
13277@kindex set com1irq
13278@kindex set com2base
13279@kindex set com2irq
13280@kindex set com3base
13281@kindex set com3irq
13282@kindex set com4base
13283@kindex set com4irq
13284@item set com1base @var{addr}
13285This command sets the base I/O port address of the @file{COM1} serial
13286port.
13287
13288@item set com1irq @var{irq}
13289This command sets the @dfn{Interrupt Request} (@code{IRQ}) line to use
13290for the @file{COM1} serial port.
13291
13292There are similar commands @samp{set com2base}, @samp{set com3irq},
13293etc.@: for setting the port address and the @code{IRQ} lines for the
13294other 3 COM ports.
13295
13296@kindex show com1base
13297@kindex show com1irq
13298@kindex show com2base
13299@kindex show com2irq
13300@kindex show com3base
13301@kindex show com3irq
13302@kindex show com4base
13303@kindex show com4irq
13304The related commands @samp{show com1base}, @samp{show com1irq} etc.@:
13305display the current settings of the base address and the @code{IRQ}
13306lines used by the COM ports.
c45da7e6
EZ
13307
13308@item info serial
13309@kindex info serial
13310@cindex DOS serial port status
13311This command prints the status of the 4 DOS serial ports. For each
13312port, it prints whether it's active or not, its I/O base address and
13313IRQ number, whether it uses a 16550-style FIFO, its baudrate, and the
13314counts of various errors encountered so far.
a8f24a35
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13315@end table
13316
13317
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13318@node Cygwin Native
13319@subsection Features for Debugging MS Windows PE executables
13320@cindex MS Windows debugging
13321@cindex native Cygwin debugging
13322@cindex Cygwin-specific commands
13323
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CF
13324@value{GDBN} supports native debugging of MS Windows programs, including
13325DLLs with and without symbolic debugging information. There are various
13326additional Cygwin-specific commands, described in this subsection. The
13327subsubsection @pxref{Non-debug DLL symbols} describes working with DLLs
13328that have no debugging symbols.
13329
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PM
13330
13331@table @code
13332@kindex info w32
13333@item info w32
13334This is a prefix of MS Windows specific commands which print
13335information about the target system and important OS structures.
13336
13337@item info w32 selector
13338This command displays information returned by
13339the Win32 API @code{GetThreadSelectorEntry} function.
13340It takes an optional argument that is evaluated to
13341a long value to give the information about this given selector.
13342Without argument, this command displays information
13343about the the six segment registers.
13344
13345@kindex info dll
13346@item info dll
13347This is a Cygwin specific alias of info shared.
13348
13349@kindex dll-symbols
13350@item dll-symbols
13351This command loads symbols from a dll similarly to
13352add-sym command but without the need to specify a base address.
13353
b383017d 13354@kindex set new-console
78c47bea 13355@item set new-console @var{mode}
b383017d 13356If @var{mode} is @code{on} the debuggee will
78c47bea
PM
13357be started in a new console on next start.
13358If @var{mode} is @code{off}i, the debuggee will
13359be started in the same console as the debugger.
13360
13361@kindex show new-console
13362@item show new-console
13363Displays whether a new console is used
13364when the debuggee is started.
13365
13366@kindex set new-group
13367@item set new-group @var{mode}
13368This boolean value controls whether the debuggee should
13369start a new group or stay in the same group as the debugger.
13370This affects the way the Windows OS handles
13371Ctrl-C.
13372
13373@kindex show new-group
13374@item show new-group
13375Displays current value of new-group boolean.
13376
13377@kindex set debugevents
13378@item set debugevents
219eec71
EZ
13379This boolean value adds debug output concerning kernel events related
13380to the debuggee seen by the debugger. This includes events that
13381signal thread and process creation and exit, DLL loading and
13382unloading, console interrupts, and debugging messages produced by the
13383Windows @code{OutputDebugString} API call.
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13384
13385@kindex set debugexec
13386@item set debugexec
b383017d 13387This boolean value adds debug output concerning execute events
219eec71 13388(such as resume thread) seen by the debugger.
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PM
13389
13390@kindex set debugexceptions
13391@item set debugexceptions
219eec71
EZ
13392This boolean value adds debug output concerning exceptions in the
13393debuggee seen by the debugger.
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13394
13395@kindex set debugmemory
13396@item set debugmemory
219eec71
EZ
13397This boolean value adds debug output concerning debuggee memory reads
13398and writes by the debugger.
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PM
13399
13400@kindex set shell
13401@item set shell
13402This boolean values specifies whether the debuggee is called
13403via a shell or directly (default value is on).
13404
13405@kindex show shell
13406@item show shell
13407Displays if the debuggee will be started with a shell.
13408
13409@end table
13410
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CF
13411@menu
13412* Non-debug DLL symbols:: Support for DLLs without debugging symbols
13413@end menu
13414
13415@node Non-debug DLL symbols
13416@subsubsection Support for DLLs without debugging symbols
13417@cindex DLLs with no debugging symbols
13418@cindex Minimal symbols and DLLs
13419
13420Very often on windows, some of the DLLs that your program relies on do
13421not include symbolic debugging information (for example,
13422@file{kernel32.dll}). When @value{GDBN} doesn't recognize any debugging
13423symbols in a DLL, it relies on the minimal amount of symbolic
13424information contained in the DLL's export table. This subsubsection
13425describes working with such symbols, known internally to @value{GDBN} as
13426``minimal symbols''.
13427
13428Note that before the debugged program has started execution, no DLLs
13429will have been loaded. The easiest way around this problem is simply to
13430start the program --- either by setting a breakpoint or letting the
13431program run once to completion. It is also possible to force
13432@value{GDBN} to load a particular DLL before starting the executable ---
13433see the shared library information in @pxref{Files} or the
13434@code{dll-symbols} command in @pxref{Cygwin Native}. Currently,
13435explicitly loading symbols from a DLL with no debugging information will
13436cause the symbol names to be duplicated in @value{GDBN}'s lookup table,
13437which may adversely affect symbol lookup performance.
13438
13439@subsubsection DLL name prefixes
13440
13441In keeping with the naming conventions used by the Microsoft debugging
13442tools, DLL export symbols are made available with a prefix based on the
13443DLL name, for instance @code{KERNEL32!CreateFileA}. The plain name is
13444also entered into the symbol table, so @code{CreateFileA} is often
13445sufficient. In some cases there will be name clashes within a program
13446(particularly if the executable itself includes full debugging symbols)
13447necessitating the use of the fully qualified name when referring to the
13448contents of the DLL. Use single-quotes around the name to avoid the
13449exclamation mark (``!'') being interpreted as a language operator.
13450
13451Note that the internal name of the DLL may be all upper-case, even
13452though the file name of the DLL is lower-case, or vice-versa. Since
13453symbols within @value{GDBN} are @emph{case-sensitive} this may cause
13454some confusion. If in doubt, try the @code{info functions} and
13455@code{info variables} commands or even @code{maint print msymbols} (see
13456@pxref{Symbols}). Here's an example:
13457
13458@smallexample
f7dc1244 13459(@value{GDBP}) info function CreateFileA
be448670
CF
13460All functions matching regular expression "CreateFileA":
13461
13462Non-debugging symbols:
134630x77e885f4 CreateFileA
134640x77e885f4 KERNEL32!CreateFileA
13465@end smallexample
13466
13467@smallexample
f7dc1244 13468(@value{GDBP}) info function !
be448670
CF
13469All functions matching regular expression "!":
13470
13471Non-debugging symbols:
134720x6100114c cygwin1!__assert
134730x61004034 cygwin1!_dll_crt0@@0
134740x61004240 cygwin1!dll_crt0(per_process *)
13475[etc...]
13476@end smallexample
13477
13478@subsubsection Working with minimal symbols
13479
13480Symbols extracted from a DLL's export table do not contain very much
13481type information. All that @value{GDBN} can do is guess whether a symbol
13482refers to a function or variable depending on the linker section that
13483contains the symbol. Also note that the actual contents of the memory
13484contained in a DLL are not available unless the program is running. This
13485means that you cannot examine the contents of a variable or disassemble
13486a function within a DLL without a running program.
13487
13488Variables are generally treated as pointers and dereferenced
13489automatically. For this reason, it is often necessary to prefix a
13490variable name with the address-of operator (``&'') and provide explicit
13491type information in the command. Here's an example of the type of
13492problem:
13493
13494@smallexample
f7dc1244 13495(@value{GDBP}) print 'cygwin1!__argv'
be448670
CF
13496$1 = 268572168
13497@end smallexample
13498
13499@smallexample
f7dc1244 13500(@value{GDBP}) x 'cygwin1!__argv'
be448670
CF
135010x10021610: "\230y\""
13502@end smallexample
13503
13504And two possible solutions:
13505
13506@smallexample
f7dc1244 13507(@value{GDBP}) print ((char **)'cygwin1!__argv')[0]
be448670
CF
13508$2 = 0x22fd98 "/cygdrive/c/mydirectory/myprogram"
13509@end smallexample
13510
13511@smallexample
f7dc1244 13512(@value{GDBP}) x/2x &'cygwin1!__argv'
be448670 135130x610c0aa8 <cygwin1!__argv>: 0x10021608 0x00000000
f7dc1244 13514(@value{GDBP}) x/x 0x10021608
be448670 135150x10021608: 0x0022fd98
f7dc1244 13516(@value{GDBP}) x/s 0x0022fd98
be448670
CF
135170x22fd98: "/cygdrive/c/mydirectory/myprogram"
13518@end smallexample
13519
13520Setting a break point within a DLL is possible even before the program
13521starts execution. However, under these circumstances, @value{GDBN} can't
13522examine the initial instructions of the function in order to skip the
13523function's frame set-up code. You can work around this by using ``*&''
13524to set the breakpoint at a raw memory address:
13525
13526@smallexample
f7dc1244 13527(@value{GDBP}) break *&'python22!PyOS_Readline'
be448670
CF
13528Breakpoint 1 at 0x1e04eff0
13529@end smallexample
13530
13531The author of these extensions is not entirely convinced that setting a
13532break point within a shared DLL like @file{kernel32.dll} is completely
13533safe.
13534
14d6dd68
EZ
13535@node Hurd Native
13536@subsection Commands specific to @sc{gnu} Hurd systems
13537@cindex @sc{gnu} Hurd debugging
13538
13539This subsection describes @value{GDBN} commands specific to the
13540@sc{gnu} Hurd native debugging.
13541
13542@table @code
13543@item set signals
13544@itemx set sigs
13545@kindex set signals@r{, Hurd command}
13546@kindex set sigs@r{, Hurd command}
13547This command toggles the state of inferior signal interception by
13548@value{GDBN}. Mach exceptions, such as breakpoint traps, are not
13549affected by this command. @code{sigs} is a shorthand alias for
13550@code{signals}.
13551
13552@item show signals
13553@itemx show sigs
13554@kindex show signals@r{, Hurd command}
13555@kindex show sigs@r{, Hurd command}
13556Show the current state of intercepting inferior's signals.
13557
13558@item set signal-thread
13559@itemx set sigthread
13560@kindex set signal-thread
13561@kindex set sigthread
13562This command tells @value{GDBN} which thread is the @code{libc} signal
13563thread. That thread is run when a signal is delivered to a running
13564process. @code{set sigthread} is the shorthand alias of @code{set
13565signal-thread}.
13566
13567@item show signal-thread
13568@itemx show sigthread
13569@kindex show signal-thread
13570@kindex show sigthread
13571These two commands show which thread will run when the inferior is
13572delivered a signal.
13573
13574@item set stopped
13575@kindex set stopped@r{, Hurd command}
13576This commands tells @value{GDBN} that the inferior process is stopped,
13577as with the @code{SIGSTOP} signal. The stopped process can be
13578continued by delivering a signal to it.
13579
13580@item show stopped
13581@kindex show stopped@r{, Hurd command}
13582This command shows whether @value{GDBN} thinks the debuggee is
13583stopped.
13584
13585@item set exceptions
13586@kindex set exceptions@r{, Hurd command}
13587Use this command to turn off trapping of exceptions in the inferior.
13588When exception trapping is off, neither breakpoints nor
13589single-stepping will work. To restore the default, set exception
13590trapping on.
13591
13592@item show exceptions
13593@kindex show exceptions@r{, Hurd command}
13594Show the current state of trapping exceptions in the inferior.
13595
13596@item set task pause
13597@kindex set task@r{, Hurd commands}
13598@cindex task attributes (@sc{gnu} Hurd)
13599@cindex pause current task (@sc{gnu} Hurd)
13600This command toggles task suspension when @value{GDBN} has control.
13601Setting it to on takes effect immediately, and the task is suspended
13602whenever @value{GDBN} gets control. Setting it to off will take
13603effect the next time the inferior is continued. If this option is set
13604to off, you can use @code{set thread default pause on} or @code{set
13605thread pause on} (see below) to pause individual threads.
13606
13607@item show task pause
13608@kindex show task@r{, Hurd commands}
13609Show the current state of task suspension.
13610
13611@item set task detach-suspend-count
13612@cindex task suspend count
13613@cindex detach from task, @sc{gnu} Hurd
13614This command sets the suspend count the task will be left with when
13615@value{GDBN} detaches from it.
13616
13617@item show task detach-suspend-count
13618Show the suspend count the task will be left with when detaching.
13619
13620@item set task exception-port
13621@itemx set task excp
13622@cindex task exception port, @sc{gnu} Hurd
13623This command sets the task exception port to which @value{GDBN} will
13624forward exceptions. The argument should be the value of the @dfn{send
13625rights} of the task. @code{set task excp} is a shorthand alias.
13626
13627@item set noninvasive
13628@cindex noninvasive task options
13629This command switches @value{GDBN} to a mode that is the least
13630invasive as far as interfering with the inferior is concerned. This
13631is the same as using @code{set task pause}, @code{set exceptions}, and
13632@code{set signals} to values opposite to the defaults.
13633
13634@item info send-rights
13635@itemx info receive-rights
13636@itemx info port-rights
13637@itemx info port-sets
13638@itemx info dead-names
13639@itemx info ports
13640@itemx info psets
13641@cindex send rights, @sc{gnu} Hurd
13642@cindex receive rights, @sc{gnu} Hurd
13643@cindex port rights, @sc{gnu} Hurd
13644@cindex port sets, @sc{gnu} Hurd
13645@cindex dead names, @sc{gnu} Hurd
13646These commands display information about, respectively, send rights,
13647receive rights, port rights, port sets, and dead names of a task.
13648There are also shorthand aliases: @code{info ports} for @code{info
13649port-rights} and @code{info psets} for @code{info port-sets}.
13650
13651@item set thread pause
13652@kindex set thread@r{, Hurd command}
13653@cindex thread properties, @sc{gnu} Hurd
13654@cindex pause current thread (@sc{gnu} Hurd)
13655This command toggles current thread suspension when @value{GDBN} has
13656control. Setting it to on takes effect immediately, and the current
13657thread is suspended whenever @value{GDBN} gets control. Setting it to
13658off will take effect the next time the inferior is continued.
13659Normally, this command has no effect, since when @value{GDBN} has
13660control, the whole task is suspended. However, if you used @code{set
13661task pause off} (see above), this command comes in handy to suspend
13662only the current thread.
13663
13664@item show thread pause
13665@kindex show thread@r{, Hurd command}
13666This command shows the state of current thread suspension.
13667
13668@item set thread run
13669This comamnd sets whether the current thread is allowed to run.
13670
13671@item show thread run
13672Show whether the current thread is allowed to run.
13673
13674@item set thread detach-suspend-count
13675@cindex thread suspend count, @sc{gnu} Hurd
13676@cindex detach from thread, @sc{gnu} Hurd
13677This command sets the suspend count @value{GDBN} will leave on a
13678thread when detaching. This number is relative to the suspend count
13679found by @value{GDBN} when it notices the thread; use @code{set thread
13680takeover-suspend-count} to force it to an absolute value.
13681
13682@item show thread detach-suspend-count
13683Show the suspend count @value{GDBN} will leave on the thread when
13684detaching.
13685
13686@item set thread exception-port
13687@itemx set thread excp
13688Set the thread exception port to which to forward exceptions. This
13689overrides the port set by @code{set task exception-port} (see above).
13690@code{set thread excp} is the shorthand alias.
13691
13692@item set thread takeover-suspend-count
13693Normally, @value{GDBN}'s thread suspend counts are relative to the
13694value @value{GDBN} finds when it notices each thread. This command
13695changes the suspend counts to be absolute instead.
13696
13697@item set thread default
13698@itemx show thread default
13699@cindex thread default settings, @sc{gnu} Hurd
13700Each of the above @code{set thread} commands has a @code{set thread
13701default} counterpart (e.g., @code{set thread default pause}, @code{set
13702thread default exception-port}, etc.). The @code{thread default}
13703variety of commands sets the default thread properties for all
13704threads; you can then change the properties of individual threads with
13705the non-default commands.
13706@end table
13707
13708
a64548ea
EZ
13709@node Neutrino
13710@subsection QNX Neutrino
13711@cindex QNX Neutrino
13712
13713@value{GDBN} provides the following commands specific to the QNX
13714Neutrino target:
13715
13716@table @code
13717@item set debug nto-debug
13718@kindex set debug nto-debug
13719When set to on, enables debugging messages specific to the QNX
13720Neutrino support.
13721
13722@item show debug nto-debug
13723@kindex show debug nto-debug
13724Show the current state of QNX Neutrino messages.
13725@end table
13726
13727
8e04817f
AC
13728@node Embedded OS
13729@section Embedded Operating Systems
104c1213 13730
8e04817f
AC
13731This section describes configurations involving the debugging of
13732embedded operating systems that are available for several different
13733architectures.
d4f3574e 13734
8e04817f
AC
13735@menu
13736* VxWorks:: Using @value{GDBN} with VxWorks
13737@end menu
104c1213 13738
8e04817f
AC
13739@value{GDBN} includes the ability to debug programs running on
13740various real-time operating systems.
104c1213 13741
8e04817f
AC
13742@node VxWorks
13743@subsection Using @value{GDBN} with VxWorks
104c1213 13744
8e04817f 13745@cindex VxWorks
104c1213 13746
8e04817f 13747@table @code
104c1213 13748
8e04817f
AC
13749@kindex target vxworks
13750@item target vxworks @var{machinename}
13751A VxWorks system, attached via TCP/IP. The argument @var{machinename}
13752is the target system's machine name or IP address.
104c1213 13753
8e04817f 13754@end table
104c1213 13755
8e04817f
AC
13756On VxWorks, @code{load} links @var{filename} dynamically on the
13757current target system as well as adding its symbols in @value{GDBN}.
104c1213 13758
8e04817f
AC
13759@value{GDBN} enables developers to spawn and debug tasks running on networked
13760VxWorks targets from a Unix host. Already-running tasks spawned from
13761the VxWorks shell can also be debugged. @value{GDBN} uses code that runs on
13762both the Unix host and on the VxWorks target. The program
13763@code{@value{GDBP}} is installed and executed on the Unix host. (It may be
13764installed with the name @code{vxgdb}, to distinguish it from a
13765@value{GDBN} for debugging programs on the host itself.)
104c1213 13766
8e04817f
AC
13767@table @code
13768@item VxWorks-timeout @var{args}
13769@kindex vxworks-timeout
13770All VxWorks-based targets now support the option @code{vxworks-timeout}.
13771This option is set by the user, and @var{args} represents the number of
13772seconds @value{GDBN} waits for responses to rpc's. You might use this if
13773your VxWorks target is a slow software simulator or is on the far side
13774of a thin network line.
13775@end table
104c1213 13776
8e04817f
AC
13777The following information on connecting to VxWorks was current when
13778this manual was produced; newer releases of VxWorks may use revised
13779procedures.
104c1213 13780
4644b6e3 13781@findex INCLUDE_RDB
8e04817f
AC
13782To use @value{GDBN} with VxWorks, you must rebuild your VxWorks kernel
13783to include the remote debugging interface routines in the VxWorks
13784library @file{rdb.a}. To do this, define @code{INCLUDE_RDB} in the
13785VxWorks configuration file @file{configAll.h} and rebuild your VxWorks
13786kernel. The resulting kernel contains @file{rdb.a}, and spawns the
13787source debugging task @code{tRdbTask} when VxWorks is booted. For more
13788information on configuring and remaking VxWorks, see the manufacturer's
13789manual.
13790@c VxWorks, see the @cite{VxWorks Programmer's Guide}.
104c1213 13791
8e04817f
AC
13792Once you have included @file{rdb.a} in your VxWorks system image and set
13793your Unix execution search path to find @value{GDBN}, you are ready to
13794run @value{GDBN}. From your Unix host, run @code{@value{GDBP}} (or
13795@code{vxgdb}, depending on your installation).
104c1213 13796
8e04817f 13797@value{GDBN} comes up showing the prompt:
104c1213 13798
474c8240 13799@smallexample
8e04817f 13800(vxgdb)
474c8240 13801@end smallexample
104c1213 13802
8e04817f
AC
13803@menu
13804* VxWorks Connection:: Connecting to VxWorks
13805* VxWorks Download:: VxWorks download
13806* VxWorks Attach:: Running tasks
13807@end menu
104c1213 13808
8e04817f
AC
13809@node VxWorks Connection
13810@subsubsection Connecting to VxWorks
104c1213 13811
8e04817f
AC
13812The @value{GDBN} command @code{target} lets you connect to a VxWorks target on the
13813network. To connect to a target whose host name is ``@code{tt}'', type:
104c1213 13814
474c8240 13815@smallexample
8e04817f 13816(vxgdb) target vxworks tt
474c8240 13817@end smallexample
104c1213 13818
8e04817f
AC
13819@need 750
13820@value{GDBN} displays messages like these:
104c1213 13821
8e04817f
AC
13822@smallexample
13823Attaching remote machine across net...
13824Connected to tt.
13825@end smallexample
104c1213 13826
8e04817f
AC
13827@need 1000
13828@value{GDBN} then attempts to read the symbol tables of any object modules
13829loaded into the VxWorks target since it was last booted. @value{GDBN} locates
13830these files by searching the directories listed in the command search
13831path (@pxref{Environment, ,Your program's environment}); if it fails
13832to find an object file, it displays a message such as:
5d161b24 13833
474c8240 13834@smallexample
8e04817f 13835prog.o: No such file or directory.
474c8240 13836@end smallexample
104c1213 13837
8e04817f
AC
13838When this happens, add the appropriate directory to the search path with
13839the @value{GDBN} command @code{path}, and execute the @code{target}
13840command again.
104c1213 13841
8e04817f
AC
13842@node VxWorks Download
13843@subsubsection VxWorks download
104c1213 13844
8e04817f
AC
13845@cindex download to VxWorks
13846If you have connected to the VxWorks target and you want to debug an
13847object that has not yet been loaded, you can use the @value{GDBN}
13848@code{load} command to download a file from Unix to VxWorks
13849incrementally. The object file given as an argument to the @code{load}
13850command is actually opened twice: first by the VxWorks target in order
13851to download the code, then by @value{GDBN} in order to read the symbol
13852table. This can lead to problems if the current working directories on
13853the two systems differ. If both systems have NFS mounted the same
13854filesystems, you can avoid these problems by using absolute paths.
13855Otherwise, it is simplest to set the working directory on both systems
13856to the directory in which the object file resides, and then to reference
13857the file by its name, without any path. For instance, a program
13858@file{prog.o} may reside in @file{@var{vxpath}/vw/demo/rdb} in VxWorks
13859and in @file{@var{hostpath}/vw/demo/rdb} on the host. To load this
13860program, type this on VxWorks:
104c1213 13861
474c8240 13862@smallexample
8e04817f 13863-> cd "@var{vxpath}/vw/demo/rdb"
474c8240 13864@end smallexample
104c1213 13865
8e04817f
AC
13866@noindent
13867Then, in @value{GDBN}, type:
104c1213 13868
474c8240 13869@smallexample
8e04817f
AC
13870(vxgdb) cd @var{hostpath}/vw/demo/rdb
13871(vxgdb) load prog.o
474c8240 13872@end smallexample
104c1213 13873
8e04817f 13874@value{GDBN} displays a response similar to this:
104c1213 13875
8e04817f
AC
13876@smallexample
13877Reading symbol data from wherever/vw/demo/rdb/prog.o... done.
13878@end smallexample
104c1213 13879
8e04817f
AC
13880You can also use the @code{load} command to reload an object module
13881after editing and recompiling the corresponding source file. Note that
13882this makes @value{GDBN} delete all currently-defined breakpoints,
13883auto-displays, and convenience variables, and to clear the value
13884history. (This is necessary in order to preserve the integrity of
13885debugger's data structures that reference the target system's symbol
13886table.)
104c1213 13887
8e04817f
AC
13888@node VxWorks Attach
13889@subsubsection Running tasks
104c1213
JM
13890
13891@cindex running VxWorks tasks
13892You can also attach to an existing task using the @code{attach} command as
13893follows:
13894
474c8240 13895@smallexample
104c1213 13896(vxgdb) attach @var{task}
474c8240 13897@end smallexample
104c1213
JM
13898
13899@noindent
13900where @var{task} is the VxWorks hexadecimal task ID. The task can be running
13901or suspended when you attach to it. Running tasks are suspended at
13902the time of attachment.
13903
6d2ebf8b 13904@node Embedded Processors
104c1213
JM
13905@section Embedded Processors
13906
13907This section goes into details specific to particular embedded
13908configurations.
13909
c45da7e6
EZ
13910@cindex send command to simulator
13911Whenever a specific embedded processor has a simulator, @value{GDBN}
13912allows to send an arbitrary command to the simulator.
13913
13914@table @code
13915@item sim @var{command}
13916@kindex sim@r{, a command}
13917Send an arbitrary @var{command} string to the simulator. Consult the
13918documentation for the specific simulator in use for information about
13919acceptable commands.
13920@end table
13921
7d86b5d5 13922
104c1213 13923@menu
c45da7e6 13924* ARM:: ARM RDI
172c2a43
KI
13925* H8/300:: Renesas H8/300
13926* H8/500:: Renesas H8/500
13927* M32R/D:: Renesas M32R/D
104c1213 13928* M68K:: Motorola M68K
104c1213 13929* MIPS Embedded:: MIPS Embedded
a37295f9 13930* OpenRISC 1000:: OpenRisc 1000
104c1213
JM
13931* PA:: HP PA Embedded
13932* PowerPC: PowerPC
172c2a43 13933* SH:: Renesas SH
104c1213
JM
13934* Sparclet:: Tsqware Sparclet
13935* Sparclite:: Fujitsu Sparclite
13936* ST2000:: Tandem ST2000
13937* Z8000:: Zilog Z8000
a64548ea
EZ
13938* AVR:: Atmel AVR
13939* CRIS:: CRIS
13940* Super-H:: Renesas Super-H
c45da7e6 13941* WinCE:: Windows CE child processes
104c1213
JM
13942@end menu
13943
6d2ebf8b 13944@node ARM
104c1213 13945@subsection ARM
c45da7e6 13946@cindex ARM RDI
104c1213
JM
13947
13948@table @code
8e04817f
AC
13949@kindex target rdi
13950@item target rdi @var{dev}
13951ARM Angel monitor, via RDI library interface to ADP protocol. You may
13952use this target to communicate with both boards running the Angel
13953monitor, or with the EmbeddedICE JTAG debug device.
13954
13955@kindex target rdp
13956@item target rdp @var{dev}
13957ARM Demon monitor.
13958
13959@end table
13960
e2f4edfd
EZ
13961@value{GDBN} provides the following ARM-specific commands:
13962
13963@table @code
13964@item set arm disassembler
13965@kindex set arm
13966This commands selects from a list of disassembly styles. The
13967@code{"std"} style is the standard style.
13968
13969@item show arm disassembler
13970@kindex show arm
13971Show the current disassembly style.
13972
13973@item set arm apcs32
13974@cindex ARM 32-bit mode
13975This command toggles ARM operation mode between 32-bit and 26-bit.
13976
13977@item show arm apcs32
13978Display the current usage of the ARM 32-bit mode.
13979
13980@item set arm fpu @var{fputype}
13981This command sets the ARM floating-point unit (FPU) type. The
13982argument @var{fputype} can be one of these:
13983
13984@table @code
13985@item auto
13986Determine the FPU type by querying the OS ABI.
13987@item softfpa
13988Software FPU, with mixed-endian doubles on little-endian ARM
13989processors.
13990@item fpa
13991GCC-compiled FPA co-processor.
13992@item softvfp
13993Software FPU with pure-endian doubles.
13994@item vfp
13995VFP co-processor.
13996@end table
13997
13998@item show arm fpu
13999Show the current type of the FPU.
14000
14001@item set arm abi
14002This command forces @value{GDBN} to use the specified ABI.
14003
14004@item show arm abi
14005Show the currently used ABI.
14006
14007@item set debug arm
14008Toggle whether to display ARM-specific debugging messages from the ARM
14009target support subsystem.
14010
14011@item show debug arm
14012Show whether ARM-specific debugging messages are enabled.
14013@end table
14014
c45da7e6
EZ
14015The following commands are available when an ARM target is debugged
14016using the RDI interface:
14017
14018@table @code
14019@item rdilogfile @r{[}@var{file}@r{]}
14020@kindex rdilogfile
14021@cindex ADP (Angel Debugger Protocol) logging
14022Set the filename for the ADP (Angel Debugger Protocol) packet log.
14023With an argument, sets the log file to the specified @var{file}. With
14024no argument, show the current log file name. The default log file is
14025@file{rdi.log}.
14026
14027@item rdilogenable @r{[}@var{arg}@r{]}
14028@kindex rdilogenable
14029Control logging of ADP packets. With an argument of 1 or @code{"yes"}
14030enables logging, with an argument 0 or @code{"no"} disables it. With
14031no arguments displays the current setting. When logging is enabled,
14032ADP packets exchanged between @value{GDBN} and the RDI target device
14033are logged to a file.
14034
14035@item set rdiromatzero
14036@kindex set rdiromatzero
14037@cindex ROM at zero address, RDI
14038Tell @value{GDBN} whether the target has ROM at address 0. If on,
14039vector catching is disabled, so that zero address can be used. If off
14040(the default), vector catching is enabled. For this command to take
14041effect, it needs to be invoked prior to the @code{target rdi} command.
14042
14043@item show rdiromatzero
14044@kindex show rdiromatzero
14045Show the current setting of ROM at zero address.
14046
14047@item set rdiheartbeat
14048@kindex set rdiheartbeat
14049@cindex RDI heartbeat
14050Enable or disable RDI heartbeat packets. It is not recommended to
14051turn on this option, since it confuses ARM and EPI JTAG interface, as
14052well as the Angel monitor.
14053
14054@item show rdiheartbeat
14055@kindex show rdiheartbeat
14056Show the setting of RDI heartbeat packets.
14057@end table
14058
e2f4edfd 14059
8e04817f 14060@node H8/300
172c2a43 14061@subsection Renesas H8/300
8e04817f
AC
14062
14063@table @code
14064
14065@kindex target hms@r{, with H8/300}
14066@item target hms @var{dev}
172c2a43 14067A Renesas SH, H8/300, or H8/500 board, attached via serial line to your host.
8e04817f
AC
14068Use special commands @code{device} and @code{speed} to control the serial
14069line and the communications speed used.
14070
14071@kindex target e7000@r{, with H8/300}
14072@item target e7000 @var{dev}
172c2a43 14073E7000 emulator for Renesas H8 and SH.
8e04817f
AC
14074
14075@kindex target sh3@r{, with H8/300}
14076@kindex target sh3e@r{, with H8/300}
14077@item target sh3 @var{dev}
14078@itemx target sh3e @var{dev}
172c2a43 14079Renesas SH-3 and SH-3E target systems.
8e04817f
AC
14080
14081@end table
14082
14083@cindex download to H8/300 or H8/500
14084@cindex H8/300 or H8/500 download
172c2a43
KI
14085@cindex download to Renesas SH
14086@cindex Renesas SH download
14087When you select remote debugging to a Renesas SH, H8/300, or H8/500
14088board, the @code{load} command downloads your program to the Renesas
8e04817f
AC
14089board and also opens it as the current executable target for
14090@value{GDBN} on your host (like the @code{file} command).
14091
14092@value{GDBN} needs to know these things to talk to your
172c2a43 14093Renesas SH, H8/300, or H8/500:
8e04817f
AC
14094
14095@enumerate
14096@item
14097that you want to use @samp{target hms}, the remote debugging interface
172c2a43
KI
14098for Renesas microprocessors, or @samp{target e7000}, the in-circuit
14099emulator for the Renesas SH and the Renesas 300H. (@samp{target hms} is
14100the default when @value{GDBN} is configured specifically for the Renesas SH,
8e04817f
AC
14101H8/300, or H8/500.)
14102
14103@item
172c2a43 14104what serial device connects your host to your Renesas board (the first
8e04817f
AC
14105serial device available on your host is the default).
14106
14107@item
14108what speed to use over the serial device.
14109@end enumerate
14110
14111@menu
172c2a43
KI
14112* Renesas Boards:: Connecting to Renesas boards.
14113* Renesas ICE:: Using the E7000 In-Circuit Emulator.
14114* Renesas Special:: Special @value{GDBN} commands for Renesas micros.
8e04817f
AC
14115@end menu
14116
172c2a43
KI
14117@node Renesas Boards
14118@subsubsection Connecting to Renesas boards
8e04817f
AC
14119
14120@c only for Unix hosts
14121@kindex device
172c2a43 14122@cindex serial device, Renesas micros
8e04817f
AC
14123Use the special @code{@value{GDBN}} command @samp{device @var{port}} if you
14124need to explicitly set the serial device. The default @var{port} is the
14125first available port on your host. This is only necessary on Unix
14126hosts, where it is typically something like @file{/dev/ttya}.
14127
14128@kindex speed
172c2a43 14129@cindex serial line speed, Renesas micros
8e04817f
AC
14130@code{@value{GDBN}} has another special command to set the communications
14131speed: @samp{speed @var{bps}}. This command also is only used from Unix
14132hosts; on DOS hosts, set the line speed as usual from outside @value{GDBN} with
14133the DOS @code{mode} command (for instance,
14134@w{@kbd{mode com2:9600,n,8,1,p}} for a 9600@dmn{bps} connection).
14135
14136The @samp{device} and @samp{speed} commands are available only when you
172c2a43 14137use a Unix host to debug your Renesas microprocessor programs. If you
8e04817f
AC
14138use a DOS host,
14139@value{GDBN} depends on an auxiliary terminate-and-stay-resident program
14140called @code{asynctsr} to communicate with the development board
14141through a PC serial port. You must also use the DOS @code{mode} command
14142to set up the serial port on the DOS side.
14143
14144The following sample session illustrates the steps needed to start a
14145program under @value{GDBN} control on an H8/300. The example uses a
14146sample H8/300 program called @file{t.x}. The procedure is the same for
172c2a43 14147the Renesas SH and the H8/500.
8e04817f
AC
14148
14149First hook up your development board. In this example, we use a
14150board attached to serial port @code{COM2}; if you use a different serial
14151port, substitute its name in the argument of the @code{mode} command.
14152When you call @code{asynctsr}, the auxiliary comms program used by the
14153debugger, you give it just the numeric part of the serial port's name;
14154for example, @samp{asyncstr 2} below runs @code{asyncstr} on
14155@code{COM2}.
14156
474c8240 14157@smallexample
8e04817f
AC
14158C:\H8300\TEST> asynctsr 2
14159C:\H8300\TEST> mode com2:9600,n,8,1,p
14160
14161Resident portion of MODE loaded
14162
14163COM2: 9600, n, 8, 1, p
14164
474c8240 14165@end smallexample
8e04817f
AC
14166
14167@quotation
14168@emph{Warning:} We have noticed a bug in PC-NFS that conflicts with
14169@code{asynctsr}. If you also run PC-NFS on your DOS host, you may need to
14170disable it, or even boot without it, to use @code{asynctsr} to control
14171your development board.
14172@end quotation
14173
14174@kindex target hms@r{, and serial protocol}
14175Now that serial communications are set up, and the development board is
9c16f35a 14176connected, you can start up @value{GDBN}. Call @code{@value{GDBN}} with
8e04817f
AC
14177the name of your program as the argument. @code{@value{GDBN}} prompts
14178you, as usual, with the prompt @samp{(@value{GDBP})}. Use two special
14179commands to begin your debugging session: @samp{target hms} to specify
172c2a43 14180cross-debugging to the Renesas board, and the @code{load} command to
8e04817f
AC
14181download your program to the board. @code{load} displays the names of
14182the program's sections, and a @samp{*} for each 2K of data downloaded.
14183(If you want to refresh @value{GDBN} data on symbols or on the
14184executable file without downloading, use the @value{GDBN} commands
14185@code{file} or @code{symbol-file}. These commands, and @code{load}
14186itself, are described in @ref{Files,,Commands to specify files}.)
14187
14188@smallexample
14189(eg-C:\H8300\TEST) @value{GDBP} t.x
14190@value{GDBN} is free software and you are welcome to distribute copies
14191 of it under certain conditions; type "show copying" to see
14192 the conditions.
14193There is absolutely no warranty for @value{GDBN}; type "show warranty"
14194for details.
14195@value{GDBN} @value{GDBVN}, Copyright 1992 Free Software Foundation, Inc...
14196(@value{GDBP}) target hms
14197Connected to remote H8/300 HMS system.
14198(@value{GDBP}) load t.x
14199.text : 0x8000 .. 0xabde ***********
14200.data : 0xabde .. 0xad30 *
14201.stack : 0xf000 .. 0xf014 *
14202@end smallexample
14203
14204At this point, you're ready to run or debug your program. From here on,
14205you can use all the usual @value{GDBN} commands. The @code{break} command
14206sets breakpoints; the @code{run} command starts your program;
14207@code{print} or @code{x} display data; the @code{continue} command
14208resumes execution after stopping at a breakpoint. You can use the
14209@code{help} command at any time to find out more about @value{GDBN} commands.
14210
14211Remember, however, that @emph{operating system} facilities aren't
14212available on your development board; for example, if your program hangs,
14213you can't send an interrupt---but you can press the @sc{reset} switch!
14214
14215Use the @sc{reset} button on the development board
14216@itemize @bullet
14217@item
14218to interrupt your program (don't use @kbd{ctl-C} on the DOS host---it has
14219no way to pass an interrupt signal to the development board); and
14220
14221@item
14222to return to the @value{GDBN} command prompt after your program finishes
14223normally. The communications protocol provides no other way for @value{GDBN}
14224to detect program completion.
14225@end itemize
14226
14227In either case, @value{GDBN} sees the effect of a @sc{reset} on the
14228development board as a ``normal exit'' of your program.
14229
172c2a43 14230@node Renesas ICE
8e04817f
AC
14231@subsubsection Using the E7000 in-circuit emulator
14232
172c2a43 14233@kindex target e7000@r{, with Renesas ICE}
8e04817f 14234You can use the E7000 in-circuit emulator to develop code for either the
172c2a43 14235Renesas SH or the H8/300H. Use one of these forms of the @samp{target
8e04817f
AC
14236e7000} command to connect @value{GDBN} to your E7000:
14237
14238@table @code
14239@item target e7000 @var{port} @var{speed}
14240Use this form if your E7000 is connected to a serial port. The
14241@var{port} argument identifies what serial port to use (for example,
14242@samp{com2}). The third argument is the line speed in bits per second
14243(for example, @samp{9600}).
14244
14245@item target e7000 @var{hostname}
14246If your E7000 is installed as a host on a TCP/IP network, you can just
14247specify its hostname; @value{GDBN} uses @code{telnet} to connect.
14248@end table
14249
ba04e063
EZ
14250The following special commands are available when debugging with the
14251Renesas E7000 ICE:
14252
14253@table @code
14254@item e7000 @var{command}
14255@kindex e7000
14256@cindex send command to E7000 monitor
14257This sends the specified @var{command} to the E7000 monitor.
14258
14259@item ftplogin @var{machine} @var{username} @var{password} @var{dir}
14260@kindex ftplogin@r{, E7000}
14261This command records information for subsequent interface with the
14262E7000 monitor via the FTP protocol: @value{GDBN} will log into the
14263named @var{machine} using specified @var{username} and @var{password},
14264and then chdir to the named directory @var{dir}.
14265
14266@item ftpload @var{file}
14267@kindex ftpload@r{, E7000}
14268This command uses credentials recorded by @code{ftplogin} to fetch and
14269load the named @var{file} from the E7000 monitor.
14270
14271@item drain
14272@kindex drain@r{, E7000}
14273This command drains any pending text buffers stored on the E7000.
14274
14275@item set usehardbreakpoints
14276@itemx show usehardbreakpoints
14277@kindex set usehardbreakpoints@r{, E7000}
14278@kindex show usehardbreakpoints@r{, E7000}
14279@cindex hardware breakpoints, and E7000
14280These commands set and show the use of hardware breakpoints for all
14281breakpoints. @xref{Set Breaks, hardware-assisted breakpoint}, for
14282more information about using hardware breakpoints selectively.
14283@end table
14284
172c2a43
KI
14285@node Renesas Special
14286@subsubsection Special @value{GDBN} commands for Renesas micros
8e04817f
AC
14287
14288Some @value{GDBN} commands are available only for the H8/300:
14289
14290@table @code
14291
14292@kindex set machine
14293@kindex show machine
14294@item set machine h8300
14295@itemx set machine h8300h
14296Condition @value{GDBN} for one of the two variants of the H8/300
14297architecture with @samp{set machine}. You can use @samp{show machine}
14298to check which variant is currently in effect.
104c1213
JM
14299
14300@end table
14301
8e04817f
AC
14302@node H8/500
14303@subsection H8/500
104c1213
JM
14304
14305@table @code
14306
8e04817f
AC
14307@kindex set memory @var{mod}
14308@cindex memory models, H8/500
14309@item set memory @var{mod}
14310@itemx show memory
14311Specify which H8/500 memory model (@var{mod}) you are using with
14312@samp{set memory}; check which memory model is in effect with @samp{show
14313memory}. The accepted values for @var{mod} are @code{small},
14314@code{big}, @code{medium}, and @code{compact}.
104c1213 14315
8e04817f 14316@end table
104c1213 14317
8e04817f 14318@node M32R/D
ba04e063 14319@subsection Renesas M32R/D and M32R/SDI
8e04817f
AC
14320
14321@table @code
8e04817f
AC
14322@kindex target m32r
14323@item target m32r @var{dev}
172c2a43 14324Renesas M32R/D ROM monitor.
8e04817f 14325
fb3e19c0
KI
14326@kindex target m32rsdi
14327@item target m32rsdi @var{dev}
14328Renesas M32R SDI server, connected via parallel port to the board.
721c2651
EZ
14329@end table
14330
14331The following @value{GDBN} commands are specific to the M32R monitor:
14332
14333@table @code
14334@item set download-path @var{path}
14335@kindex set download-path
14336@cindex find downloadable @sc{srec} files (M32R)
14337Set the default path for finding donwloadable @sc{srec} files.
14338
14339@item show download-path
14340@kindex show download-path
14341Show the default path for downloadable @sc{srec} files.
fb3e19c0 14342
721c2651
EZ
14343@item set board-address @var{addr}
14344@kindex set board-address
14345@cindex M32-EVA target board address
14346Set the IP address for the M32R-EVA target board.
14347
14348@item show board-address
14349@kindex show board-address
14350Show the current IP address of the target board.
14351
14352@item set server-address @var{addr}
14353@kindex set server-address
14354@cindex download server address (M32R)
14355Set the IP address for the download server, which is the @value{GDBN}'s
14356host machine.
14357
14358@item show server-address
14359@kindex show server-address
14360Display the IP address of the download server.
14361
14362@item upload @r{[}@var{file}@r{]}
14363@kindex upload@r{, M32R}
14364Upload the specified @sc{srec} @var{file} via the monitor's Ethernet
14365upload capability. If no @var{file} argument is given, the current
14366executable file is uploaded.
14367
14368@item tload @r{[}@var{file}@r{]}
14369@kindex tload@r{, M32R}
14370Test the @code{upload} command.
8e04817f
AC
14371@end table
14372
ba04e063
EZ
14373The following commands are available for M32R/SDI:
14374
14375@table @code
14376@item sdireset
14377@kindex sdireset
14378@cindex reset SDI connection, M32R
14379This command resets the SDI connection.
14380
14381@item sdistatus
14382@kindex sdistatus
14383This command shows the SDI connection status.
14384
14385@item debug_chaos
14386@kindex debug_chaos
14387@cindex M32R/Chaos debugging
14388Instructs the remote that M32R/Chaos debugging is to be used.
14389
14390@item use_debug_dma
14391@kindex use_debug_dma
14392Instructs the remote to use the DEBUG_DMA method of accessing memory.
14393
14394@item use_mon_code
14395@kindex use_mon_code
14396Instructs the remote to use the MON_CODE method of accessing memory.
14397
14398@item use_ib_break
14399@kindex use_ib_break
14400Instructs the remote to set breakpoints by IB break.
14401
14402@item use_dbt_break
14403@kindex use_dbt_break
14404Instructs the remote to set breakpoints by DBT.
14405@end table
14406
8e04817f
AC
14407@node M68K
14408@subsection M68k
14409
14410The Motorola m68k configuration includes ColdFire support, and
14411target command for the following ROM monitors.
14412
14413@table @code
14414
14415@kindex target abug
14416@item target abug @var{dev}
14417ABug ROM monitor for M68K.
14418
14419@kindex target cpu32bug
14420@item target cpu32bug @var{dev}
14421CPU32BUG monitor, running on a CPU32 (M68K) board.
14422
14423@kindex target dbug
14424@item target dbug @var{dev}
14425dBUG ROM monitor for Motorola ColdFire.
14426
14427@kindex target est
14428@item target est @var{dev}
14429EST-300 ICE monitor, running on a CPU32 (M68K) board.
14430
14431@kindex target rom68k
14432@item target rom68k @var{dev}
14433ROM 68K monitor, running on an M68K IDP board.
14434
14435@end table
14436
8e04817f
AC
14437@table @code
14438
14439@kindex target rombug
14440@item target rombug @var{dev}
14441ROMBUG ROM monitor for OS/9000.
14442
14443@end table
14444
8e04817f
AC
14445@node MIPS Embedded
14446@subsection MIPS Embedded
14447
14448@cindex MIPS boards
14449@value{GDBN} can use the MIPS remote debugging protocol to talk to a
14450MIPS board attached to a serial line. This is available when
14451you configure @value{GDBN} with @samp{--target=mips-idt-ecoff}.
104c1213 14452
8e04817f
AC
14453@need 1000
14454Use these @value{GDBN} commands to specify the connection to your target board:
104c1213 14455
8e04817f
AC
14456@table @code
14457@item target mips @var{port}
14458@kindex target mips @var{port}
14459To run a program on the board, start up @code{@value{GDBP}} with the
14460name of your program as the argument. To connect to the board, use the
14461command @samp{target mips @var{port}}, where @var{port} is the name of
14462the serial port connected to the board. If the program has not already
14463been downloaded to the board, you may use the @code{load} command to
14464download it. You can then use all the usual @value{GDBN} commands.
104c1213 14465
8e04817f
AC
14466For example, this sequence connects to the target board through a serial
14467port, and loads and runs a program called @var{prog} through the
14468debugger:
104c1213 14469
474c8240 14470@smallexample
8e04817f
AC
14471host$ @value{GDBP} @var{prog}
14472@value{GDBN} is free software and @dots{}
14473(@value{GDBP}) target mips /dev/ttyb
14474(@value{GDBP}) load @var{prog}
14475(@value{GDBP}) run
474c8240 14476@end smallexample
104c1213 14477
8e04817f
AC
14478@item target mips @var{hostname}:@var{portnumber}
14479On some @value{GDBN} host configurations, you can specify a TCP
14480connection (for instance, to a serial line managed by a terminal
14481concentrator) instead of a serial port, using the syntax
14482@samp{@var{hostname}:@var{portnumber}}.
104c1213 14483
8e04817f
AC
14484@item target pmon @var{port}
14485@kindex target pmon @var{port}
14486PMON ROM monitor.
104c1213 14487
8e04817f
AC
14488@item target ddb @var{port}
14489@kindex target ddb @var{port}
14490NEC's DDB variant of PMON for Vr4300.
104c1213 14491
8e04817f
AC
14492@item target lsi @var{port}
14493@kindex target lsi @var{port}
14494LSI variant of PMON.
104c1213 14495
8e04817f
AC
14496@kindex target r3900
14497@item target r3900 @var{dev}
14498Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips.
104c1213 14499
8e04817f
AC
14500@kindex target array
14501@item target array @var{dev}
14502Array Tech LSI33K RAID controller board.
104c1213 14503
8e04817f 14504@end table
104c1213 14505
104c1213 14506
8e04817f
AC
14507@noindent
14508@value{GDBN} also supports these special commands for MIPS targets:
104c1213 14509
8e04817f 14510@table @code
8e04817f
AC
14511@item set mipsfpu double
14512@itemx set mipsfpu single
14513@itemx set mipsfpu none
a64548ea 14514@itemx set mipsfpu auto
8e04817f
AC
14515@itemx show mipsfpu
14516@kindex set mipsfpu
14517@kindex show mipsfpu
14518@cindex MIPS remote floating point
14519@cindex floating point, MIPS remote
14520If your target board does not support the MIPS floating point
14521coprocessor, you should use the command @samp{set mipsfpu none} (if you
14522need this, you may wish to put the command in your @value{GDBN} init
14523file). This tells @value{GDBN} how to find the return value of
14524functions which return floating point values. It also allows
14525@value{GDBN} to avoid saving the floating point registers when calling
14526functions on the board. If you are using a floating point coprocessor
14527with only single precision floating point support, as on the @sc{r4650}
14528processor, use the command @samp{set mipsfpu single}. The default
14529double precision floating point coprocessor may be selected using
14530@samp{set mipsfpu double}.
104c1213 14531
8e04817f
AC
14532In previous versions the only choices were double precision or no
14533floating point, so @samp{set mipsfpu on} will select double precision
14534and @samp{set mipsfpu off} will select no floating point.
104c1213 14535
8e04817f
AC
14536As usual, you can inquire about the @code{mipsfpu} variable with
14537@samp{show mipsfpu}.
104c1213 14538
8e04817f
AC
14539@item set timeout @var{seconds}
14540@itemx set retransmit-timeout @var{seconds}
14541@itemx show timeout
14542@itemx show retransmit-timeout
14543@cindex @code{timeout}, MIPS protocol
14544@cindex @code{retransmit-timeout}, MIPS protocol
14545@kindex set timeout
14546@kindex show timeout
14547@kindex set retransmit-timeout
14548@kindex show retransmit-timeout
14549You can control the timeout used while waiting for a packet, in the MIPS
14550remote protocol, with the @code{set timeout @var{seconds}} command. The
14551default is 5 seconds. Similarly, you can control the timeout used while
14552waiting for an acknowledgement of a packet with the @code{set
14553retransmit-timeout @var{seconds}} command. The default is 3 seconds.
14554You can inspect both values with @code{show timeout} and @code{show
14555retransmit-timeout}. (These commands are @emph{only} available when
14556@value{GDBN} is configured for @samp{--target=mips-idt-ecoff}.)
104c1213 14557
8e04817f
AC
14558The timeout set by @code{set timeout} does not apply when @value{GDBN}
14559is waiting for your program to stop. In that case, @value{GDBN} waits
14560forever because it has no way of knowing how long the program is going
14561to run before stopping.
ba04e063
EZ
14562
14563@item set syn-garbage-limit @var{num}
14564@kindex set syn-garbage-limit@r{, MIPS remote}
14565@cindex synchronize with remote MIPS target
14566Limit the maximum number of characters @value{GDBN} should ignore when
14567it tries to synchronize with the remote target. The default is 10
14568characters. Setting the limit to -1 means there's no limit.
14569
14570@item show syn-garbage-limit
14571@kindex show syn-garbage-limit@r{, MIPS remote}
14572Show the current limit on the number of characters to ignore when
14573trying to synchronize with the remote system.
14574
14575@item set monitor-prompt @var{prompt}
14576@kindex set monitor-prompt@r{, MIPS remote}
14577@cindex remote monitor prompt
14578Tell @value{GDBN} to expect the specified @var{prompt} string from the
14579remote monitor. The default depends on the target:
14580@table @asis
14581@item pmon target
14582@samp{PMON}
14583@item ddb target
14584@samp{NEC010}
14585@item lsi target
14586@samp{PMON>}
14587@end table
14588
14589@item show monitor-prompt
14590@kindex show monitor-prompt@r{, MIPS remote}
14591Show the current strings @value{GDBN} expects as the prompt from the
14592remote monitor.
14593
14594@item set monitor-warnings
14595@kindex set monitor-warnings@r{, MIPS remote}
14596Enable or disable monitor warnings about hardware breakpoints. This
14597has effect only for the @code{lsi} target. When on, @value{GDBN} will
14598display warning messages whose codes are returned by the @code{lsi}
14599PMON monitor for breakpoint commands.
14600
14601@item show monitor-warnings
14602@kindex show monitor-warnings@r{, MIPS remote}
14603Show the current setting of printing monitor warnings.
14604
14605@item pmon @var{command}
14606@kindex pmon@r{, MIPS remote}
14607@cindex send PMON command
14608This command allows sending an arbitrary @var{command} string to the
14609monitor. The monitor must be in debug mode for this to work.
8e04817f 14610@end table
104c1213 14611
a37295f9
MM
14612@node OpenRISC 1000
14613@subsection OpenRISC 1000
14614@cindex OpenRISC 1000
14615
14616@cindex or1k boards
14617See OR1k Architecture document (@uref{www.opencores.org}) for more information
14618about platform and commands.
14619
14620@table @code
14621
14622@kindex target jtag
14623@item target jtag jtag://@var{host}:@var{port}
14624
14625Connects to remote JTAG server.
14626JTAG remote server can be either an or1ksim or JTAG server,
14627connected via parallel port to the board.
14628
14629Example: @code{target jtag jtag://localhost:9999}
14630
14631@kindex or1ksim
14632@item or1ksim @var{command}
14633If connected to @code{or1ksim} OpenRISC 1000 Architectural
14634Simulator, proprietary commands can be executed.
14635
14636@kindex info or1k spr
14637@item info or1k spr
14638Displays spr groups.
14639
14640@item info or1k spr @var{group}
14641@itemx info or1k spr @var{groupno}
14642Displays register names in selected group.
14643
14644@item info or1k spr @var{group} @var{register}
14645@itemx info or1k spr @var{register}
14646@itemx info or1k spr @var{groupno} @var{registerno}
14647@itemx info or1k spr @var{registerno}
14648Shows information about specified spr register.
14649
14650@kindex spr
14651@item spr @var{group} @var{register} @var{value}
14652@itemx spr @var{register @var{value}}
14653@itemx spr @var{groupno} @var{registerno @var{value}}
14654@itemx spr @var{registerno @var{value}}
14655Writes @var{value} to specified spr register.
14656@end table
14657
14658Some implementations of OpenRISC 1000 Architecture also have hardware trace.
14659It is very similar to @value{GDBN} trace, except it does not interfere with normal
14660program execution and is thus much faster. Hardware breakpoints/watchpoint
14661triggers can be set using:
14662@table @code
14663@item $LEA/$LDATA
14664Load effective address/data
14665@item $SEA/$SDATA
14666Store effective address/data
14667@item $AEA/$ADATA
14668Access effective address ($SEA or $LEA) or data ($SDATA/$LDATA)
14669@item $FETCH
14670Fetch data
14671@end table
14672
14673When triggered, it can capture low level data, like: @code{PC}, @code{LSEA},
14674@code{LDATA}, @code{SDATA}, @code{READSPR}, @code{WRITESPR}, @code{INSTR}.
14675
14676@code{htrace} commands:
14677@cindex OpenRISC 1000 htrace
14678@table @code
14679@kindex hwatch
14680@item hwatch @var{conditional}
14681Set hardware watchpoint on combination of Load/Store Effecive Address(es)
14682or Data. For example:
14683
14684@code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)}
14685
14686@code{hwatch ($LEA == my_var) && ($LDATA < 50) || ($SEA == my_var) && ($SDATA >= 50)}
14687
4644b6e3 14688@kindex htrace
a37295f9
MM
14689@item htrace info
14690Display information about current HW trace configuration.
14691
a37295f9
MM
14692@item htrace trigger @var{conditional}
14693Set starting criteria for HW trace.
14694
a37295f9
MM
14695@item htrace qualifier @var{conditional}
14696Set acquisition qualifier for HW trace.
14697
a37295f9
MM
14698@item htrace stop @var{conditional}
14699Set HW trace stopping criteria.
14700
f153cc92 14701@item htrace record [@var{data}]*
a37295f9
MM
14702Selects the data to be recorded, when qualifier is met and HW trace was
14703triggered.
14704
a37295f9 14705@item htrace enable
a37295f9
MM
14706@itemx htrace disable
14707Enables/disables the HW trace.
14708
f153cc92 14709@item htrace rewind [@var{filename}]
a37295f9
MM
14710Clears currently recorded trace data.
14711
14712If filename is specified, new trace file is made and any newly collected data
14713will be written there.
14714
f153cc92 14715@item htrace print [@var{start} [@var{len}]]
a37295f9
MM
14716Prints trace buffer, using current record configuration.
14717
a37295f9
MM
14718@item htrace mode continuous
14719Set continuous trace mode.
14720
a37295f9
MM
14721@item htrace mode suspend
14722Set suspend trace mode.
14723
14724@end table
14725
8e04817f
AC
14726@node PowerPC
14727@subsection PowerPC
104c1213
JM
14728
14729@table @code
8e04817f
AC
14730@kindex target dink32
14731@item target dink32 @var{dev}
14732DINK32 ROM monitor.
104c1213 14733
8e04817f
AC
14734@kindex target ppcbug
14735@item target ppcbug @var{dev}
14736@kindex target ppcbug1
14737@item target ppcbug1 @var{dev}
14738PPCBUG ROM monitor for PowerPC.
104c1213 14739
8e04817f
AC
14740@kindex target sds
14741@item target sds @var{dev}
14742SDS monitor, running on a PowerPC board (such as Motorola's ADS).
c45da7e6 14743@end table
8e04817f 14744
c45da7e6
EZ
14745@cindex SDS protocol
14746The following commands specifi to the SDS protocol are supported
14747by@value{GDBN}:
14748
14749@table @code
14750@item set sdstimeout @var{nsec}
14751@kindex set sdstimeout
14752Set the timeout for SDS protocol reads to be @var{nsec} seconds. The
14753default is 2 seconds.
14754
14755@item show sdstimeout
14756@kindex show sdstimeout
14757Show the current value of the SDS timeout.
14758
14759@item sds @var{command}
14760@kindex sds@r{, a command}
14761Send the specified @var{command} string to the SDS monitor.
8e04817f
AC
14762@end table
14763
c45da7e6 14764
8e04817f
AC
14765@node PA
14766@subsection HP PA Embedded
104c1213
JM
14767
14768@table @code
14769
8e04817f
AC
14770@kindex target op50n
14771@item target op50n @var{dev}
14772OP50N monitor, running on an OKI HPPA board.
14773
14774@kindex target w89k
14775@item target w89k @var{dev}
14776W89K monitor, running on a Winbond HPPA board.
104c1213
JM
14777
14778@end table
14779
8e04817f 14780@node SH
172c2a43 14781@subsection Renesas SH
104c1213
JM
14782
14783@table @code
14784
172c2a43 14785@kindex target hms@r{, with Renesas SH}
8e04817f 14786@item target hms @var{dev}
172c2a43 14787A Renesas SH board attached via serial line to your host. Use special
8e04817f
AC
14788commands @code{device} and @code{speed} to control the serial line and
14789the communications speed used.
104c1213 14790
172c2a43 14791@kindex target e7000@r{, with Renesas SH}
8e04817f 14792@item target e7000 @var{dev}
172c2a43 14793E7000 emulator for Renesas SH.
104c1213 14794
8e04817f
AC
14795@kindex target sh3@r{, with SH}
14796@kindex target sh3e@r{, with SH}
14797@item target sh3 @var{dev}
14798@item target sh3e @var{dev}
172c2a43 14799Renesas SH-3 and SH-3E target systems.
104c1213 14800
8e04817f 14801@end table
104c1213 14802
8e04817f
AC
14803@node Sparclet
14804@subsection Tsqware Sparclet
104c1213 14805
8e04817f
AC
14806@cindex Sparclet
14807
14808@value{GDBN} enables developers to debug tasks running on
14809Sparclet targets from a Unix host.
14810@value{GDBN} uses code that runs on
14811both the Unix host and on the Sparclet target. The program
14812@code{@value{GDBP}} is installed and executed on the Unix host.
104c1213 14813
8e04817f
AC
14814@table @code
14815@item remotetimeout @var{args}
14816@kindex remotetimeout
14817@value{GDBN} supports the option @code{remotetimeout}.
14818This option is set by the user, and @var{args} represents the number of
14819seconds @value{GDBN} waits for responses.
104c1213
JM
14820@end table
14821
8e04817f
AC
14822@cindex compiling, on Sparclet
14823When compiling for debugging, include the options @samp{-g} to get debug
14824information and @samp{-Ttext} to relocate the program to where you wish to
14825load it on the target. You may also want to add the options @samp{-n} or
14826@samp{-N} in order to reduce the size of the sections. Example:
104c1213 14827
474c8240 14828@smallexample
8e04817f 14829sparclet-aout-gcc prog.c -Ttext 0x12010000 -g -o prog -N
474c8240 14830@end smallexample
104c1213 14831
8e04817f 14832You can use @code{objdump} to verify that the addresses are what you intended:
104c1213 14833
474c8240 14834@smallexample
8e04817f 14835sparclet-aout-objdump --headers --syms prog
474c8240 14836@end smallexample
104c1213 14837
8e04817f
AC
14838@cindex running, on Sparclet
14839Once you have set
14840your Unix execution search path to find @value{GDBN}, you are ready to
14841run @value{GDBN}. From your Unix host, run @code{@value{GDBP}}
14842(or @code{sparclet-aout-gdb}, depending on your installation).
104c1213 14843
8e04817f
AC
14844@value{GDBN} comes up showing the prompt:
14845
474c8240 14846@smallexample
8e04817f 14847(gdbslet)
474c8240 14848@end smallexample
104c1213
JM
14849
14850@menu
8e04817f
AC
14851* Sparclet File:: Setting the file to debug
14852* Sparclet Connection:: Connecting to Sparclet
14853* Sparclet Download:: Sparclet download
14854* Sparclet Execution:: Running and debugging
104c1213
JM
14855@end menu
14856
8e04817f
AC
14857@node Sparclet File
14858@subsubsection Setting file to debug
104c1213 14859
8e04817f 14860The @value{GDBN} command @code{file} lets you choose with program to debug.
104c1213 14861
474c8240 14862@smallexample
8e04817f 14863(gdbslet) file prog
474c8240 14864@end smallexample
104c1213 14865
8e04817f
AC
14866@need 1000
14867@value{GDBN} then attempts to read the symbol table of @file{prog}.
14868@value{GDBN} locates
14869the file by searching the directories listed in the command search
14870path.
14871If the file was compiled with debug information (option "-g"), source
14872files will be searched as well.
14873@value{GDBN} locates
14874the source files by searching the directories listed in the directory search
14875path (@pxref{Environment, ,Your program's environment}).
14876If it fails
14877to find a file, it displays a message such as:
104c1213 14878
474c8240 14879@smallexample
8e04817f 14880prog: No such file or directory.
474c8240 14881@end smallexample
104c1213 14882
8e04817f
AC
14883When this happens, add the appropriate directories to the search paths with
14884the @value{GDBN} commands @code{path} and @code{dir}, and execute the
14885@code{target} command again.
104c1213 14886
8e04817f
AC
14887@node Sparclet Connection
14888@subsubsection Connecting to Sparclet
104c1213 14889
8e04817f
AC
14890The @value{GDBN} command @code{target} lets you connect to a Sparclet target.
14891To connect to a target on serial port ``@code{ttya}'', type:
104c1213 14892
474c8240 14893@smallexample
8e04817f
AC
14894(gdbslet) target sparclet /dev/ttya
14895Remote target sparclet connected to /dev/ttya
14896main () at ../prog.c:3
474c8240 14897@end smallexample
104c1213 14898
8e04817f
AC
14899@need 750
14900@value{GDBN} displays messages like these:
104c1213 14901
474c8240 14902@smallexample
8e04817f 14903Connected to ttya.
474c8240 14904@end smallexample
104c1213 14905
8e04817f
AC
14906@node Sparclet Download
14907@subsubsection Sparclet download
104c1213 14908
8e04817f
AC
14909@cindex download to Sparclet
14910Once connected to the Sparclet target,
14911you can use the @value{GDBN}
14912@code{load} command to download the file from the host to the target.
14913The file name and load offset should be given as arguments to the @code{load}
14914command.
14915Since the file format is aout, the program must be loaded to the starting
14916address. You can use @code{objdump} to find out what this value is. The load
14917offset is an offset which is added to the VMA (virtual memory address)
14918of each of the file's sections.
14919For instance, if the program
14920@file{prog} was linked to text address 0x1201000, with data at 0x12010160
14921and bss at 0x12010170, in @value{GDBN}, type:
104c1213 14922
474c8240 14923@smallexample
8e04817f
AC
14924(gdbslet) load prog 0x12010000
14925Loading section .text, size 0xdb0 vma 0x12010000
474c8240 14926@end smallexample
104c1213 14927
8e04817f
AC
14928If the code is loaded at a different address then what the program was linked
14929to, you may need to use the @code{section} and @code{add-symbol-file} commands
14930to tell @value{GDBN} where to map the symbol table.
14931
14932@node Sparclet Execution
14933@subsubsection Running and debugging
14934
14935@cindex running and debugging Sparclet programs
14936You can now begin debugging the task using @value{GDBN}'s execution control
14937commands, @code{b}, @code{step}, @code{run}, etc. See the @value{GDBN}
14938manual for the list of commands.
14939
474c8240 14940@smallexample
8e04817f
AC
14941(gdbslet) b main
14942Breakpoint 1 at 0x12010000: file prog.c, line 3.
14943(gdbslet) run
14944Starting program: prog
14945Breakpoint 1, main (argc=1, argv=0xeffff21c) at prog.c:3
149463 char *symarg = 0;
14947(gdbslet) step
149484 char *execarg = "hello!";
14949(gdbslet)
474c8240 14950@end smallexample
8e04817f
AC
14951
14952@node Sparclite
14953@subsection Fujitsu Sparclite
104c1213
JM
14954
14955@table @code
14956
8e04817f
AC
14957@kindex target sparclite
14958@item target sparclite @var{dev}
14959Fujitsu sparclite boards, used only for the purpose of loading.
14960You must use an additional command to debug the program.
14961For example: target remote @var{dev} using @value{GDBN} standard
14962remote protocol.
104c1213
JM
14963
14964@end table
14965
8e04817f
AC
14966@node ST2000
14967@subsection Tandem ST2000
104c1213 14968
8e04817f
AC
14969@value{GDBN} may be used with a Tandem ST2000 phone switch, running Tandem's
14970STDBUG protocol.
104c1213 14971
8e04817f
AC
14972To connect your ST2000 to the host system, see the manufacturer's
14973manual. Once the ST2000 is physically attached, you can run:
104c1213 14974
474c8240 14975@smallexample
8e04817f 14976target st2000 @var{dev} @var{speed}
474c8240 14977@end smallexample
104c1213 14978
8e04817f
AC
14979@noindent
14980to establish it as your debugging environment. @var{dev} is normally
14981the name of a serial device, such as @file{/dev/ttya}, connected to the
14982ST2000 via a serial line. You can instead specify @var{dev} as a TCP
14983connection (for example, to a serial line attached via a terminal
14984concentrator) using the syntax @code{@var{hostname}:@var{portnumber}}.
104c1213 14985
8e04817f
AC
14986The @code{load} and @code{attach} commands are @emph{not} defined for
14987this target; you must load your program into the ST2000 as you normally
14988would for standalone operation. @value{GDBN} reads debugging information
14989(such as symbols) from a separate, debugging version of the program
14990available on your host computer.
14991@c FIXME!! This is terribly vague; what little content is here is
14992@c basically hearsay.
104c1213 14993
8e04817f
AC
14994@cindex ST2000 auxiliary commands
14995These auxiliary @value{GDBN} commands are available to help you with the ST2000
14996environment:
104c1213 14997
8e04817f
AC
14998@table @code
14999@item st2000 @var{command}
15000@kindex st2000 @var{cmd}
15001@cindex STDBUG commands (ST2000)
15002@cindex commands to STDBUG (ST2000)
15003Send a @var{command} to the STDBUG monitor. See the manufacturer's
15004manual for available commands.
104c1213 15005
8e04817f
AC
15006@item connect
15007@cindex connect (to STDBUG)
15008Connect the controlling terminal to the STDBUG command monitor. When
15009you are done interacting with STDBUG, typing either of two character
15010sequences gets you back to the @value{GDBN} command prompt:
15011@kbd{@key{RET}~.} (Return, followed by tilde and period) or
15012@kbd{@key{RET}~@key{C-d}} (Return, followed by tilde and control-D).
104c1213
JM
15013@end table
15014
8e04817f
AC
15015@node Z8000
15016@subsection Zilog Z8000
104c1213 15017
8e04817f
AC
15018@cindex Z8000
15019@cindex simulator, Z8000
15020@cindex Zilog Z8000 simulator
104c1213 15021
8e04817f
AC
15022When configured for debugging Zilog Z8000 targets, @value{GDBN} includes
15023a Z8000 simulator.
15024
15025For the Z8000 family, @samp{target sim} simulates either the Z8002 (the
15026unsegmented variant of the Z8000 architecture) or the Z8001 (the
15027segmented variant). The simulator recognizes which architecture is
15028appropriate by inspecting the object code.
104c1213 15029
8e04817f
AC
15030@table @code
15031@item target sim @var{args}
15032@kindex sim
15033@kindex target sim@r{, with Z8000}
15034Debug programs on a simulated CPU. If the simulator supports setup
15035options, specify them via @var{args}.
104c1213
JM
15036@end table
15037
8e04817f
AC
15038@noindent
15039After specifying this target, you can debug programs for the simulated
15040CPU in the same style as programs for your host computer; use the
15041@code{file} command to load a new program image, the @code{run} command
15042to run your program, and so on.
15043
15044As well as making available all the usual machine registers
15045(@pxref{Registers, ,Registers}), the Z8000 simulator provides three
15046additional items of information as specially named registers:
104c1213
JM
15047
15048@table @code
15049
8e04817f
AC
15050@item cycles
15051Counts clock-ticks in the simulator.
104c1213 15052
8e04817f
AC
15053@item insts
15054Counts instructions run in the simulator.
104c1213 15055
8e04817f
AC
15056@item time
15057Execution time in 60ths of a second.
104c1213 15058
8e04817f 15059@end table
104c1213 15060
8e04817f
AC
15061You can refer to these values in @value{GDBN} expressions with the usual
15062conventions; for example, @w{@samp{b fputc if $cycles>5000}} sets a
15063conditional breakpoint that suspends only after at least 5000
15064simulated clock ticks.
104c1213 15065
a64548ea
EZ
15066@node AVR
15067@subsection Atmel AVR
15068@cindex AVR
15069
15070When configured for debugging the Atmel AVR, @value{GDBN} supports the
15071following AVR-specific commands:
15072
15073@table @code
15074@item info io_registers
15075@kindex info io_registers@r{, AVR}
15076@cindex I/O registers (Atmel AVR)
15077This command displays information about the AVR I/O registers. For
15078each register, @value{GDBN} prints its number and value.
15079@end table
15080
15081@node CRIS
15082@subsection CRIS
15083@cindex CRIS
15084
15085When configured for debugging CRIS, @value{GDBN} provides the
15086following CRIS-specific commands:
15087
15088@table @code
15089@item set cris-version @var{ver}
15090@cindex CRIS version
e22e55c9
OF
15091Set the current CRIS version to @var{ver}, either @samp{10} or @samp{32}.
15092The CRIS version affects register names and sizes. This command is useful in
15093case autodetection of the CRIS version fails.
a64548ea
EZ
15094
15095@item show cris-version
15096Show the current CRIS version.
15097
15098@item set cris-dwarf2-cfi
15099@cindex DWARF-2 CFI and CRIS
e22e55c9
OF
15100Set the usage of DWARF-2 CFI for CRIS debugging. The default is @samp{on}.
15101Change to @samp{off} when using @code{gcc-cris} whose version is below
15102@code{R59}.
a64548ea
EZ
15103
15104@item show cris-dwarf2-cfi
15105Show the current state of using DWARF-2 CFI.
e22e55c9
OF
15106
15107@item set cris-mode @var{mode}
15108@cindex CRIS mode
15109Set the current CRIS mode to @var{mode}. It should only be changed when
15110debugging in guru mode, in which case it should be set to
15111@samp{guru} (the default is @samp{normal}).
15112
15113@item show cris-mode
15114Show the current CRIS mode.
a64548ea
EZ
15115@end table
15116
15117@node Super-H
15118@subsection Renesas Super-H
15119@cindex Super-H
15120
15121For the Renesas Super-H processor, @value{GDBN} provides these
15122commands:
15123
15124@table @code
15125@item regs
15126@kindex regs@r{, Super-H}
15127Show the values of all Super-H registers.
15128@end table
15129
c45da7e6
EZ
15130@node WinCE
15131@subsection Windows CE
15132@cindex Windows CE
15133
15134The following commands are available for Windows CE:
15135
15136@table @code
15137@item set remotedirectory @var{dir}
15138@kindex set remotedirectory
15139Tell @value{GDBN} to upload files from the named directory @var{dir}.
15140The default is @file{/gdb}, i.e.@: the root directory on the current
15141drive.
15142
15143@item show remotedirectory
15144@kindex show remotedirectory
15145Show the current value of the upload directory.
15146
15147@item set remoteupload @var{method}
15148@kindex set remoteupload
15149Set the method used to upload files to remote device. Valid values
15150for @var{method} are @samp{always}, @samp{newer}, and @samp{never}.
15151The default is @samp{newer}.
15152
15153@item show remoteupload
15154@kindex show remoteupload
15155Show the current setting of the upload method.
15156
15157@item set remoteaddhost
15158@kindex set remoteaddhost
15159Tell @value{GDBN} whether to add this host to the remote stub's
15160arguments when you debug over a network.
15161
15162@item show remoteaddhost
15163@kindex show remoteaddhost
15164Show whether to add this host to remote stub's arguments when
15165debugging over a network.
15166@end table
15167
a64548ea 15168
8e04817f
AC
15169@node Architectures
15170@section Architectures
104c1213 15171
8e04817f
AC
15172This section describes characteristics of architectures that affect
15173all uses of @value{GDBN} with the architecture, both native and cross.
104c1213 15174
8e04817f 15175@menu
9c16f35a 15176* i386::
8e04817f
AC
15177* A29K::
15178* Alpha::
15179* MIPS::
a64548ea 15180* HPPA:: HP PA architecture
8e04817f 15181@end menu
104c1213 15182
9c16f35a
EZ
15183@node i386
15184@subsection x86 Architecture-specific issues.
15185
15186@table @code
15187@item set struct-convention @var{mode}
15188@kindex set struct-convention
15189@cindex struct return convention
15190@cindex struct/union returned in registers
15191Set the convention used by the inferior to return @code{struct}s and
15192@code{union}s from functions to @var{mode}. Possible values of
15193@var{mode} are @code{"pcc"}, @code{"reg"}, and @code{"default"} (the
15194default). @code{"default"} or @code{"pcc"} means that @code{struct}s
15195are returned on the stack, while @code{"reg"} means that a
15196@code{struct} or a @code{union} whose size is 1, 2, 4, or 8 bytes will
15197be returned in a register.
15198
15199@item show struct-convention
15200@kindex show struct-convention
15201Show the current setting of the convention to return @code{struct}s
15202from functions.
15203@end table
15204
8e04817f
AC
15205@node A29K
15206@subsection A29K
104c1213
JM
15207
15208@table @code
104c1213 15209
8e04817f
AC
15210@kindex set rstack_high_address
15211@cindex AMD 29K register stack
15212@cindex register stack, AMD29K
15213@item set rstack_high_address @var{address}
15214On AMD 29000 family processors, registers are saved in a separate
15215@dfn{register stack}. There is no way for @value{GDBN} to determine the
15216extent of this stack. Normally, @value{GDBN} just assumes that the
15217stack is ``large enough''. This may result in @value{GDBN} referencing
15218memory locations that do not exist. If necessary, you can get around
15219this problem by specifying the ending address of the register stack with
15220the @code{set rstack_high_address} command. The argument should be an
15221address, which you probably want to precede with @samp{0x} to specify in
15222hexadecimal.
104c1213 15223
8e04817f
AC
15224@kindex show rstack_high_address
15225@item show rstack_high_address
15226Display the current limit of the register stack, on AMD 29000 family
15227processors.
104c1213 15228
8e04817f 15229@end table
104c1213 15230
8e04817f
AC
15231@node Alpha
15232@subsection Alpha
104c1213 15233
8e04817f 15234See the following section.
104c1213 15235
8e04817f
AC
15236@node MIPS
15237@subsection MIPS
104c1213 15238
8e04817f
AC
15239@cindex stack on Alpha
15240@cindex stack on MIPS
15241@cindex Alpha stack
15242@cindex MIPS stack
15243Alpha- and MIPS-based computers use an unusual stack frame, which
15244sometimes requires @value{GDBN} to search backward in the object code to
15245find the beginning of a function.
104c1213 15246
8e04817f
AC
15247@cindex response time, MIPS debugging
15248To improve response time (especially for embedded applications, where
15249@value{GDBN} may be restricted to a slow serial line for this search)
15250you may want to limit the size of this search, using one of these
15251commands:
104c1213 15252
8e04817f
AC
15253@table @code
15254@cindex @code{heuristic-fence-post} (Alpha, MIPS)
15255@item set heuristic-fence-post @var{limit}
15256Restrict @value{GDBN} to examining at most @var{limit} bytes in its
15257search for the beginning of a function. A value of @var{0} (the
15258default) means there is no limit. However, except for @var{0}, the
15259larger the limit the more bytes @code{heuristic-fence-post} must search
e2f4edfd
EZ
15260and therefore the longer it takes to run. You should only need to use
15261this command when debugging a stripped executable.
104c1213 15262
8e04817f
AC
15263@item show heuristic-fence-post
15264Display the current limit.
15265@end table
104c1213
JM
15266
15267@noindent
8e04817f
AC
15268These commands are available @emph{only} when @value{GDBN} is configured
15269for debugging programs on Alpha or MIPS processors.
104c1213 15270
a64548ea
EZ
15271Several MIPS-specific commands are available when debugging MIPS
15272programs:
15273
15274@table @code
15275@item set mips saved-gpreg-size @var{size}
15276@kindex set mips saved-gpreg-size
15277@cindex MIPS GP register size on stack
15278Set the size of MIPS general-purpose registers saved on the stack.
15279The argument @var{size} can be one of the following:
15280
15281@table @samp
15282@item 32
1528332-bit GP registers
15284@item 64
1528564-bit GP registers
15286@item auto
15287Use the target's default setting or autodetect the saved size from the
15288information contained in the executable. This is the default
15289@end table
15290
15291@item show mips saved-gpreg-size
15292@kindex show mips saved-gpreg-size
15293Show the current size of MIPS GP registers on the stack.
15294
15295@item set mips stack-arg-size @var{size}
15296@kindex set mips stack-arg-size
15297@cindex MIPS stack space for arguments
15298Set the amount of stack space reserved for arguments to functions.
15299The argument can be one of @code{"32"}, @code{"64"} or @code{"auto"}
15300(the default).
15301
15302@item set mips abi @var{arg}
15303@kindex set mips abi
15304@cindex set ABI for MIPS
15305Tell @value{GDBN} which MIPS ABI is used by the inferior. Possible
15306values of @var{arg} are:
15307
15308@table @samp
15309@item auto
15310The default ABI associated with the current binary (this is the
15311default).
15312@item o32
15313@item o64
15314@item n32
15315@item n64
15316@item eabi32
15317@item eabi64
15318@item auto
15319@end table
15320
15321@item show mips abi
15322@kindex show mips abi
15323Show the MIPS ABI used by @value{GDBN} to debug the inferior.
15324
15325@item set mipsfpu
15326@itemx show mipsfpu
15327@xref{MIPS Embedded, set mipsfpu}.
15328
15329@item set mips mask-address @var{arg}
15330@kindex set mips mask-address
15331@cindex MIPS addresses, masking
15332This command determines whether the most-significant 32 bits of 64-bit
15333MIPS addresses are masked off. The argument @var{arg} can be
15334@samp{on}, @samp{off}, or @samp{auto}. The latter is the default
15335setting, which lets @value{GDBN} determine the correct value.
15336
15337@item show mips mask-address
15338@kindex show mips mask-address
15339Show whether the upper 32 bits of MIPS addresses are masked off or
15340not.
15341
15342@item set remote-mips64-transfers-32bit-regs
15343@kindex set remote-mips64-transfers-32bit-regs
15344This command controls compatibility with 64-bit MIPS targets that
15345transfer data in 32-bit quantities. If you have an old MIPS 64 target
15346that transfers 32 bits for some registers, like @sc{sr} and @sc{fsr},
15347and 64 bits for other registers, set this option to @samp{on}.
15348
15349@item show remote-mips64-transfers-32bit-regs
15350@kindex show remote-mips64-transfers-32bit-regs
15351Show the current setting of compatibility with older MIPS 64 targets.
15352
15353@item set debug mips
15354@kindex set debug mips
15355This command turns on and off debugging messages for the MIPS-specific
15356target code in @value{GDBN}.
15357
15358@item show debug mips
15359@kindex show debug mips
15360Show the current setting of MIPS debugging messages.
15361@end table
15362
15363
15364@node HPPA
15365@subsection HPPA
15366@cindex HPPA support
15367
15368When @value{GDBN} is debugging te HP PA architecture, it provides the
15369following special commands:
15370
15371@table @code
15372@item set debug hppa
15373@kindex set debug hppa
15374THis command determines whether HPPA architecture specific debugging
15375messages are to be displayed.
15376
15377@item show debug hppa
15378Show whether HPPA debugging messages are displayed.
15379
15380@item maint print unwind @var{address}
15381@kindex maint print unwind@r{, HPPA}
15382This command displays the contents of the unwind table entry at the
15383given @var{address}.
15384
15385@end table
15386
104c1213 15387
8e04817f
AC
15388@node Controlling GDB
15389@chapter Controlling @value{GDBN}
15390
15391You can alter the way @value{GDBN} interacts with you by using the
15392@code{set} command. For commands controlling how @value{GDBN} displays
15393data, see @ref{Print Settings, ,Print settings}. Other settings are
15394described here.
15395
15396@menu
15397* Prompt:: Prompt
15398* Editing:: Command editing
d620b259 15399* Command History:: Command history
8e04817f
AC
15400* Screen Size:: Screen size
15401* Numbers:: Numbers
1e698235 15402* ABI:: Configuring the current ABI
8e04817f
AC
15403* Messages/Warnings:: Optional warnings and messages
15404* Debugging Output:: Optional messages about internal happenings
15405@end menu
15406
15407@node Prompt
15408@section Prompt
104c1213 15409
8e04817f 15410@cindex prompt
104c1213 15411
8e04817f
AC
15412@value{GDBN} indicates its readiness to read a command by printing a string
15413called the @dfn{prompt}. This string is normally @samp{(@value{GDBP})}. You
15414can change the prompt string with the @code{set prompt} command. For
15415instance, when debugging @value{GDBN} with @value{GDBN}, it is useful to change
15416the prompt in one of the @value{GDBN} sessions so that you can always tell
15417which one you are talking to.
104c1213 15418
8e04817f
AC
15419@emph{Note:} @code{set prompt} does not add a space for you after the
15420prompt you set. This allows you to set a prompt which ends in a space
15421or a prompt that does not.
104c1213 15422
8e04817f
AC
15423@table @code
15424@kindex set prompt
15425@item set prompt @var{newprompt}
15426Directs @value{GDBN} to use @var{newprompt} as its prompt string henceforth.
104c1213 15427
8e04817f
AC
15428@kindex show prompt
15429@item show prompt
15430Prints a line of the form: @samp{Gdb's prompt is: @var{your-prompt}}
104c1213
JM
15431@end table
15432
8e04817f
AC
15433@node Editing
15434@section Command editing
15435@cindex readline
15436@cindex command line editing
104c1213 15437
703663ab 15438@value{GDBN} reads its input commands via the @dfn{Readline} interface. This
8e04817f
AC
15439@sc{gnu} library provides consistent behavior for programs which provide a
15440command line interface to the user. Advantages are @sc{gnu} Emacs-style
15441or @dfn{vi}-style inline editing of commands, @code{csh}-like history
15442substitution, and a storage and recall of command history across
15443debugging sessions.
104c1213 15444
8e04817f
AC
15445You may control the behavior of command line editing in @value{GDBN} with the
15446command @code{set}.
104c1213 15447
8e04817f
AC
15448@table @code
15449@kindex set editing
15450@cindex editing
15451@item set editing
15452@itemx set editing on
15453Enable command line editing (enabled by default).
104c1213 15454
8e04817f
AC
15455@item set editing off
15456Disable command line editing.
104c1213 15457
8e04817f
AC
15458@kindex show editing
15459@item show editing
15460Show whether command line editing is enabled.
104c1213
JM
15461@end table
15462
703663ab
EZ
15463@xref{Command Line Editing}, for more details about the Readline
15464interface. Users unfamiliar with @sc{gnu} Emacs or @code{vi} are
15465encouraged to read that chapter.
15466
d620b259 15467@node Command History
8e04817f 15468@section Command history
703663ab 15469@cindex command history
8e04817f
AC
15470
15471@value{GDBN} can keep track of the commands you type during your
15472debugging sessions, so that you can be certain of precisely what
15473happened. Use these commands to manage the @value{GDBN} command
15474history facility.
104c1213 15475
703663ab
EZ
15476@value{GDBN} uses the @sc{gnu} History library, a part of the Readline
15477package, to provide the history facility. @xref{Using History
15478Interactively}, for the detailed description of the History library.
15479
d620b259
NR
15480To issue a command to @value{GDBN} without affecting certain aspects of
15481the state which is seen by users, prefix it with @samp{server }. This
15482means that this command will not affect the command history, nor will it
15483affect @value{GDBN}'s notion of which command to repeat if @key{RET} is
15484pressed on a line by itself.
15485
15486@cindex @code{server}, command prefix
15487The server prefix does not affect the recording of values into the value
15488history; to print a value without recording it into the value history,
15489use the @code{output} command instead of the @code{print} command.
15490
703663ab
EZ
15491Here is the description of @value{GDBN} commands related to command
15492history.
15493
104c1213 15494@table @code
8e04817f
AC
15495@cindex history substitution
15496@cindex history file
15497@kindex set history filename
4644b6e3 15498@cindex @env{GDBHISTFILE}, environment variable
8e04817f
AC
15499@item set history filename @var{fname}
15500Set the name of the @value{GDBN} command history file to @var{fname}.
15501This is the file where @value{GDBN} reads an initial command history
15502list, and where it writes the command history from this session when it
15503exits. You can access this list through history expansion or through
15504the history command editing characters listed below. This file defaults
15505to the value of the environment variable @code{GDBHISTFILE}, or to
15506@file{./.gdb_history} (@file{./_gdb_history} on MS-DOS) if this variable
15507is not set.
104c1213 15508
9c16f35a
EZ
15509@cindex save command history
15510@kindex set history save
8e04817f
AC
15511@item set history save
15512@itemx set history save on
15513Record command history in a file, whose name may be specified with the
15514@code{set history filename} command. By default, this option is disabled.
104c1213 15515
8e04817f
AC
15516@item set history save off
15517Stop recording command history in a file.
104c1213 15518
8e04817f 15519@cindex history size
9c16f35a 15520@kindex set history size
6fc08d32 15521@cindex @env{HISTSIZE}, environment variable
8e04817f
AC
15522@item set history size @var{size}
15523Set the number of commands which @value{GDBN} keeps in its history list.
15524This defaults to the value of the environment variable
15525@code{HISTSIZE}, or to 256 if this variable is not set.
104c1213
JM
15526@end table
15527
8e04817f 15528History expansion assigns special meaning to the character @kbd{!}.
703663ab 15529@xref{Event Designators}, for more details.
8e04817f 15530
703663ab 15531@cindex history expansion, turn on/off
8e04817f
AC
15532Since @kbd{!} is also the logical not operator in C, history expansion
15533is off by default. If you decide to enable history expansion with the
15534@code{set history expansion on} command, you may sometimes need to
15535follow @kbd{!} (when it is used as logical not, in an expression) with
15536a space or a tab to prevent it from being expanded. The readline
15537history facilities do not attempt substitution on the strings
15538@kbd{!=} and @kbd{!(}, even when history expansion is enabled.
15539
15540The commands to control history expansion are:
104c1213
JM
15541
15542@table @code
8e04817f
AC
15543@item set history expansion on
15544@itemx set history expansion
703663ab 15545@kindex set history expansion
8e04817f 15546Enable history expansion. History expansion is off by default.
104c1213 15547
8e04817f
AC
15548@item set history expansion off
15549Disable history expansion.
104c1213 15550
8e04817f
AC
15551@c @group
15552@kindex show history
15553@item show history
15554@itemx show history filename
15555@itemx show history save
15556@itemx show history size
15557@itemx show history expansion
15558These commands display the state of the @value{GDBN} history parameters.
15559@code{show history} by itself displays all four states.
15560@c @end group
15561@end table
15562
15563@table @code
9c16f35a
EZ
15564@kindex show commands
15565@cindex show last commands
15566@cindex display command history
8e04817f
AC
15567@item show commands
15568Display the last ten commands in the command history.
104c1213 15569
8e04817f
AC
15570@item show commands @var{n}
15571Print ten commands centered on command number @var{n}.
15572
15573@item show commands +
15574Print ten commands just after the commands last printed.
104c1213
JM
15575@end table
15576
8e04817f
AC
15577@node Screen Size
15578@section Screen size
15579@cindex size of screen
15580@cindex pauses in output
104c1213 15581
8e04817f
AC
15582Certain commands to @value{GDBN} may produce large amounts of
15583information output to the screen. To help you read all of it,
15584@value{GDBN} pauses and asks you for input at the end of each page of
15585output. Type @key{RET} when you want to continue the output, or @kbd{q}
15586to discard the remaining output. Also, the screen width setting
15587determines when to wrap lines of output. Depending on what is being
15588printed, @value{GDBN} tries to break the line at a readable place,
15589rather than simply letting it overflow onto the following line.
15590
15591Normally @value{GDBN} knows the size of the screen from the terminal
15592driver software. For example, on Unix @value{GDBN} uses the termcap data base
15593together with the value of the @code{TERM} environment variable and the
15594@code{stty rows} and @code{stty cols} settings. If this is not correct,
15595you can override it with the @code{set height} and @code{set
15596width} commands:
15597
15598@table @code
15599@kindex set height
15600@kindex set width
15601@kindex show width
15602@kindex show height
15603@item set height @var{lpp}
15604@itemx show height
15605@itemx set width @var{cpl}
15606@itemx show width
15607These @code{set} commands specify a screen height of @var{lpp} lines and
15608a screen width of @var{cpl} characters. The associated @code{show}
15609commands display the current settings.
104c1213 15610
8e04817f
AC
15611If you specify a height of zero lines, @value{GDBN} does not pause during
15612output no matter how long the output is. This is useful if output is to a
15613file or to an editor buffer.
104c1213 15614
8e04817f
AC
15615Likewise, you can specify @samp{set width 0} to prevent @value{GDBN}
15616from wrapping its output.
9c16f35a
EZ
15617
15618@item set pagination on
15619@itemx set pagination off
15620@kindex set pagination
15621Turn the output pagination on or off; the default is on. Turning
15622pagination off is the alternative to @code{set height 0}.
15623
15624@item show pagination
15625@kindex show pagination
15626Show the current pagination mode.
104c1213
JM
15627@end table
15628
8e04817f
AC
15629@node Numbers
15630@section Numbers
15631@cindex number representation
15632@cindex entering numbers
104c1213 15633
8e04817f
AC
15634You can always enter numbers in octal, decimal, or hexadecimal in
15635@value{GDBN} by the usual conventions: octal numbers begin with
15636@samp{0}, decimal numbers end with @samp{.}, and hexadecimal numbers
eb2dae08
EZ
15637begin with @samp{0x}. Numbers that neither begin with @samp{0} or
15638@samp{0x}, nor end with a @samp{.} are, by default, entered in base
1563910; likewise, the default display for numbers---when no particular
15640format is specified---is base 10. You can change the default base for
15641both input and output with the commands described below.
104c1213 15642
8e04817f
AC
15643@table @code
15644@kindex set input-radix
15645@item set input-radix @var{base}
15646Set the default base for numeric input. Supported choices
15647for @var{base} are decimal 8, 10, or 16. @var{base} must itself be
eb2dae08 15648specified either unambiguously or using the current input radix; for
8e04817f 15649example, any of
104c1213 15650
8e04817f 15651@smallexample
9c16f35a
EZ
15652set input-radix 012
15653set input-radix 10.
15654set input-radix 0xa
8e04817f 15655@end smallexample
104c1213 15656
8e04817f 15657@noindent
9c16f35a 15658sets the input base to decimal. On the other hand, @samp{set input-radix 10}
eb2dae08
EZ
15659leaves the input radix unchanged, no matter what it was, since
15660@samp{10}, being without any leading or trailing signs of its base, is
15661interpreted in the current radix. Thus, if the current radix is 16,
15662@samp{10} is interpreted in hex, i.e.@: as 16 decimal, which doesn't
15663change the radix.
104c1213 15664
8e04817f
AC
15665@kindex set output-radix
15666@item set output-radix @var{base}
15667Set the default base for numeric display. Supported choices
15668for @var{base} are decimal 8, 10, or 16. @var{base} must itself be
eb2dae08 15669specified either unambiguously or using the current input radix.
104c1213 15670
8e04817f
AC
15671@kindex show input-radix
15672@item show input-radix
15673Display the current default base for numeric input.
104c1213 15674
8e04817f
AC
15675@kindex show output-radix
15676@item show output-radix
15677Display the current default base for numeric display.
9c16f35a
EZ
15678
15679@item set radix @r{[}@var{base}@r{]}
15680@itemx show radix
15681@kindex set radix
15682@kindex show radix
15683These commands set and show the default base for both input and output
15684of numbers. @code{set radix} sets the radix of input and output to
15685the same base; without an argument, it resets the radix back to its
15686default value of 10.
15687
8e04817f 15688@end table
104c1213 15689
1e698235
DJ
15690@node ABI
15691@section Configuring the current ABI
15692
15693@value{GDBN} can determine the @dfn{ABI} (Application Binary Interface) of your
15694application automatically. However, sometimes you need to override its
15695conclusions. Use these commands to manage @value{GDBN}'s view of the
15696current ABI.
15697
98b45e30
DJ
15698@cindex OS ABI
15699@kindex set osabi
b4e9345d 15700@kindex show osabi
98b45e30
DJ
15701
15702One @value{GDBN} configuration can debug binaries for multiple operating
b383017d 15703system targets, either via remote debugging or native emulation.
98b45e30
DJ
15704@value{GDBN} will autodetect the @dfn{OS ABI} (Operating System ABI) in use,
15705but you can override its conclusion using the @code{set osabi} command.
15706One example where this is useful is in debugging of binaries which use
15707an alternate C library (e.g.@: @sc{uClibc} for @sc{gnu}/Linux) which does
15708not have the same identifying marks that the standard C library for your
15709platform provides.
15710
15711@table @code
15712@item show osabi
15713Show the OS ABI currently in use.
15714
15715@item set osabi
15716With no argument, show the list of registered available OS ABI's.
15717
15718@item set osabi @var{abi}
15719Set the current OS ABI to @var{abi}.
15720@end table
15721
1e698235 15722@cindex float promotion
1e698235
DJ
15723
15724Generally, the way that an argument of type @code{float} is passed to a
15725function depends on whether the function is prototyped. For a prototyped
15726(i.e.@: ANSI/ISO style) function, @code{float} arguments are passed unchanged,
15727according to the architecture's convention for @code{float}. For unprototyped
15728(i.e.@: K&R style) functions, @code{float} arguments are first promoted to type
15729@code{double} and then passed.
15730
15731Unfortunately, some forms of debug information do not reliably indicate whether
15732a function is prototyped. If @value{GDBN} calls a function that is not marked
15733as prototyped, it consults @kbd{set coerce-float-to-double}.
15734
15735@table @code
a8f24a35 15736@kindex set coerce-float-to-double
1e698235
DJ
15737@item set coerce-float-to-double
15738@itemx set coerce-float-to-double on
15739Arguments of type @code{float} will be promoted to @code{double} when passed
15740to an unprototyped function. This is the default setting.
15741
15742@item set coerce-float-to-double off
15743Arguments of type @code{float} will be passed directly to unprototyped
15744functions.
9c16f35a
EZ
15745
15746@kindex show coerce-float-to-double
15747@item show coerce-float-to-double
15748Show the current setting of promoting @code{float} to @code{double}.
1e698235
DJ
15749@end table
15750
f1212245
DJ
15751@kindex set cp-abi
15752@kindex show cp-abi
15753@value{GDBN} needs to know the ABI used for your program's C@t{++}
15754objects. The correct C@t{++} ABI depends on which C@t{++} compiler was
15755used to build your application. @value{GDBN} only fully supports
15756programs with a single C@t{++} ABI; if your program contains code using
15757multiple C@t{++} ABI's or if @value{GDBN} can not identify your
15758program's ABI correctly, you can tell @value{GDBN} which ABI to use.
15759Currently supported ABI's include ``gnu-v2'', for @code{g++} versions
15760before 3.0, ``gnu-v3'', for @code{g++} versions 3.0 and later, and
15761``hpaCC'' for the HP ANSI C@t{++} compiler. Other C@t{++} compilers may
15762use the ``gnu-v2'' or ``gnu-v3'' ABI's as well. The default setting is
15763``auto''.
15764
15765@table @code
15766@item show cp-abi
15767Show the C@t{++} ABI currently in use.
15768
15769@item set cp-abi
15770With no argument, show the list of supported C@t{++} ABI's.
15771
15772@item set cp-abi @var{abi}
15773@itemx set cp-abi auto
15774Set the current C@t{++} ABI to @var{abi}, or return to automatic detection.
15775@end table
15776
8e04817f
AC
15777@node Messages/Warnings
15778@section Optional warnings and messages
104c1213 15779
9c16f35a
EZ
15780@cindex verbose operation
15781@cindex optional warnings
8e04817f
AC
15782By default, @value{GDBN} is silent about its inner workings. If you are
15783running on a slow machine, you may want to use the @code{set verbose}
15784command. This makes @value{GDBN} tell you when it does a lengthy
15785internal operation, so you will not think it has crashed.
104c1213 15786
8e04817f
AC
15787Currently, the messages controlled by @code{set verbose} are those
15788which announce that the symbol table for a source file is being read;
15789see @code{symbol-file} in @ref{Files, ,Commands to specify files}.
104c1213 15790
8e04817f
AC
15791@table @code
15792@kindex set verbose
15793@item set verbose on
15794Enables @value{GDBN} output of certain informational messages.
104c1213 15795
8e04817f
AC
15796@item set verbose off
15797Disables @value{GDBN} output of certain informational messages.
104c1213 15798
8e04817f
AC
15799@kindex show verbose
15800@item show verbose
15801Displays whether @code{set verbose} is on or off.
15802@end table
104c1213 15803
8e04817f
AC
15804By default, if @value{GDBN} encounters bugs in the symbol table of an
15805object file, it is silent; but if you are debugging a compiler, you may
15806find this information useful (@pxref{Symbol Errors, ,Errors reading
15807symbol files}).
104c1213 15808
8e04817f 15809@table @code
104c1213 15810
8e04817f
AC
15811@kindex set complaints
15812@item set complaints @var{limit}
15813Permits @value{GDBN} to output @var{limit} complaints about each type of
15814unusual symbols before becoming silent about the problem. Set
15815@var{limit} to zero to suppress all complaints; set it to a large number
15816to prevent complaints from being suppressed.
104c1213 15817
8e04817f
AC
15818@kindex show complaints
15819@item show complaints
15820Displays how many symbol complaints @value{GDBN} is permitted to produce.
104c1213 15821
8e04817f 15822@end table
104c1213 15823
8e04817f
AC
15824By default, @value{GDBN} is cautious, and asks what sometimes seems to be a
15825lot of stupid questions to confirm certain commands. For example, if
15826you try to run a program which is already running:
104c1213 15827
474c8240 15828@smallexample
8e04817f
AC
15829(@value{GDBP}) run
15830The program being debugged has been started already.
15831Start it from the beginning? (y or n)
474c8240 15832@end smallexample
104c1213 15833
8e04817f
AC
15834If you are willing to unflinchingly face the consequences of your own
15835commands, you can disable this ``feature'':
104c1213 15836
8e04817f 15837@table @code
104c1213 15838
8e04817f
AC
15839@kindex set confirm
15840@cindex flinching
15841@cindex confirmation
15842@cindex stupid questions
15843@item set confirm off
15844Disables confirmation requests.
104c1213 15845
8e04817f
AC
15846@item set confirm on
15847Enables confirmation requests (the default).
104c1213 15848
8e04817f
AC
15849@kindex show confirm
15850@item show confirm
15851Displays state of confirmation requests.
15852
15853@end table
104c1213 15854
8e04817f
AC
15855@node Debugging Output
15856@section Optional messages about internal happenings
4644b6e3
EZ
15857@cindex optional debugging messages
15858
da316a69
EZ
15859@value{GDBN} has commands that enable optional debugging messages from
15860various @value{GDBN} subsystems; normally these commands are of
15861interest to @value{GDBN} maintainers, or when reporting a bug. This
15862section documents those commands.
15863
104c1213 15864@table @code
a8f24a35
EZ
15865@kindex set exec-done-display
15866@item set exec-done-display
15867Turns on or off the notification of asynchronous commands'
15868completion. When on, @value{GDBN} will print a message when an
15869asynchronous command finishes its execution. The default is off.
15870@kindex show exec-done-display
15871@item show exec-done-display
15872Displays the current setting of asynchronous command completion
15873notification.
4644b6e3
EZ
15874@kindex set debug
15875@cindex gdbarch debugging info
a8f24a35 15876@cindex architecture debugging info
8e04817f 15877@item set debug arch
a8f24a35 15878Turns on or off display of gdbarch debugging info. The default is off
4644b6e3 15879@kindex show debug
8e04817f
AC
15880@item show debug arch
15881Displays the current state of displaying gdbarch debugging info.
721c2651
EZ
15882@item set debug aix-thread
15883@cindex AIX threads
15884Display debugging messages about inner workings of the AIX thread
15885module.
15886@item show debug aix-thread
15887Show the current state of AIX thread debugging info display.
8e04817f 15888@item set debug event
4644b6e3 15889@cindex event debugging info
a8f24a35 15890Turns on or off display of @value{GDBN} event debugging info. The
8e04817f 15891default is off.
8e04817f
AC
15892@item show debug event
15893Displays the current state of displaying @value{GDBN} event debugging
15894info.
8e04817f 15895@item set debug expression
4644b6e3 15896@cindex expression debugging info
721c2651
EZ
15897Turns on or off display of debugging info about @value{GDBN}
15898expression parsing. The default is off.
8e04817f 15899@item show debug expression
721c2651
EZ
15900Displays the current state of displaying debugging info about
15901@value{GDBN} expression parsing.
7453dc06 15902@item set debug frame
4644b6e3 15903@cindex frame debugging info
7453dc06
AC
15904Turns on or off display of @value{GDBN} frame debugging info. The
15905default is off.
7453dc06
AC
15906@item show debug frame
15907Displays the current state of displaying @value{GDBN} frame debugging
15908info.
30e91e0b
RC
15909@item set debug infrun
15910@cindex inferior debugging info
15911Turns on or off display of @value{GDBN} debugging info for running the inferior.
15912The default is off. @file{infrun.c} contains GDB's runtime state machine used
15913for implementing operations such as single-stepping the inferior.
15914@item show debug infrun
15915Displays the current state of @value{GDBN} inferior debugging.
da316a69
EZ
15916@item set debug lin-lwp
15917@cindex @sc{gnu}/Linux LWP debug messages
15918@cindex Linux lightweight processes
721c2651 15919Turns on or off debugging messages from the Linux LWP debug support.
da316a69
EZ
15920@item show debug lin-lwp
15921Show the current state of Linux LWP debugging messages.
2b4855ab 15922@item set debug observer
4644b6e3 15923@cindex observer debugging info
2b4855ab
AC
15924Turns on or off display of @value{GDBN} observer debugging. This
15925includes info such as the notification of observable events.
2b4855ab
AC
15926@item show debug observer
15927Displays the current state of observer debugging.
8e04817f 15928@item set debug overload
4644b6e3 15929@cindex C@t{++} overload debugging info
8e04817f 15930Turns on or off display of @value{GDBN} C@t{++} overload debugging
359df76b 15931info. This includes info such as ranking of functions, etc. The default
8e04817f 15932is off.
8e04817f
AC
15933@item show debug overload
15934Displays the current state of displaying @value{GDBN} C@t{++} overload
15935debugging info.
8e04817f
AC
15936@cindex packets, reporting on stdout
15937@cindex serial connections, debugging
15938@item set debug remote
15939Turns on or off display of reports on all packets sent back and forth across
15940the serial line to the remote machine. The info is printed on the
15941@value{GDBN} standard output stream. The default is off.
8e04817f
AC
15942@item show debug remote
15943Displays the state of display of remote packets.
8e04817f
AC
15944@item set debug serial
15945Turns on or off display of @value{GDBN} serial debugging info. The
15946default is off.
8e04817f
AC
15947@item show debug serial
15948Displays the current state of displaying @value{GDBN} serial debugging
15949info.
c45da7e6
EZ
15950@item set debug solib-frv
15951@cindex FR-V shared-library debugging
15952Turns on or off debugging messages for FR-V shared-library code.
15953@item show debug solib-frv
15954Display the current state of FR-V shared-library code debugging
15955messages.
8e04817f 15956@item set debug target
4644b6e3 15957@cindex target debugging info
8e04817f
AC
15958Turns on or off display of @value{GDBN} target debugging info. This info
15959includes what is going on at the target level of GDB, as it happens. The
701b08bb
DJ
15960default is 0. Set it to 1 to track events, and to 2 to also track the
15961value of large memory transfers. Changes to this flag do not take effect
15962until the next time you connect to a target or use the @code{run} command.
8e04817f
AC
15963@item show debug target
15964Displays the current state of displaying @value{GDBN} target debugging
15965info.
c45da7e6 15966@item set debugvarobj
4644b6e3 15967@cindex variable object debugging info
8e04817f
AC
15968Turns on or off display of @value{GDBN} variable object debugging
15969info. The default is off.
c45da7e6 15970@item show debugvarobj
8e04817f
AC
15971Displays the current state of displaying @value{GDBN} variable object
15972debugging info.
15973@end table
104c1213 15974
8e04817f
AC
15975@node Sequences
15976@chapter Canned Sequences of Commands
104c1213 15977
8e04817f
AC
15978Aside from breakpoint commands (@pxref{Break Commands, ,Breakpoint
15979command lists}), @value{GDBN} provides two ways to store sequences of
15980commands for execution as a unit: user-defined commands and command
15981files.
104c1213 15982
8e04817f 15983@menu
fcc73fe3
EZ
15984* Define:: How to define your own commands
15985* Hooks:: Hooks for user-defined commands
15986* Command Files:: How to write scripts of commands to be stored in a file
15987* Output:: Commands for controlled output
8e04817f 15988@end menu
104c1213 15989
8e04817f
AC
15990@node Define
15991@section User-defined commands
104c1213 15992
8e04817f 15993@cindex user-defined command
fcc73fe3 15994@cindex arguments, to user-defined commands
8e04817f
AC
15995A @dfn{user-defined command} is a sequence of @value{GDBN} commands to
15996which you assign a new name as a command. This is done with the
15997@code{define} command. User commands may accept up to 10 arguments
15998separated by whitespace. Arguments are accessed within the user command
c03c782f 15999via @code{$arg0@dots{}$arg9}. A trivial example:
104c1213 16000
8e04817f
AC
16001@smallexample
16002define adder
16003 print $arg0 + $arg1 + $arg2
c03c782f 16004end
8e04817f 16005@end smallexample
104c1213
JM
16006
16007@noindent
8e04817f 16008To execute the command use:
104c1213 16009
8e04817f
AC
16010@smallexample
16011adder 1 2 3
16012@end smallexample
104c1213 16013
8e04817f
AC
16014@noindent
16015This defines the command @code{adder}, which prints the sum of
16016its three arguments. Note the arguments are text substitutions, so they may
16017reference variables, use complex expressions, or even perform inferior
16018functions calls.
104c1213 16019
fcc73fe3
EZ
16020@cindex argument count in user-defined commands
16021@cindex how many arguments (user-defined commands)
c03c782f
AS
16022In addition, @code{$argc} may be used to find out how many arguments have
16023been passed. This expands to a number in the range 0@dots{}10.
16024
16025@smallexample
16026define adder
16027 if $argc == 2
16028 print $arg0 + $arg1
16029 end
16030 if $argc == 3
16031 print $arg0 + $arg1 + $arg2
16032 end
16033end
16034@end smallexample
16035
104c1213 16036@table @code
104c1213 16037
8e04817f
AC
16038@kindex define
16039@item define @var{commandname}
16040Define a command named @var{commandname}. If there is already a command
16041by that name, you are asked to confirm that you want to redefine it.
104c1213 16042
8e04817f
AC
16043The definition of the command is made up of other @value{GDBN} command lines,
16044which are given following the @code{define} command. The end of these
16045commands is marked by a line containing @code{end}.
104c1213 16046
8e04817f 16047@kindex document
ca91424e 16048@kindex end@r{ (user-defined commands)}
8e04817f
AC
16049@item document @var{commandname}
16050Document the user-defined command @var{commandname}, so that it can be
16051accessed by @code{help}. The command @var{commandname} must already be
16052defined. This command reads lines of documentation just as @code{define}
16053reads the lines of the command definition, ending with @code{end}.
16054After the @code{document} command is finished, @code{help} on command
16055@var{commandname} displays the documentation you have written.
104c1213 16056
8e04817f
AC
16057You may use the @code{document} command again to change the
16058documentation of a command. Redefining the command with @code{define}
16059does not change the documentation.
104c1213 16060
c45da7e6
EZ
16061@kindex dont-repeat
16062@cindex don't repeat command
16063@item dont-repeat
16064Used inside a user-defined command, this tells @value{GDBN} that this
16065command should not be repeated when the user hits @key{RET}
16066(@pxref{Command Syntax, repeat last command}).
16067
8e04817f
AC
16068@kindex help user-defined
16069@item help user-defined
16070List all user-defined commands, with the first line of the documentation
16071(if any) for each.
104c1213 16072
8e04817f
AC
16073@kindex show user
16074@item show user
16075@itemx show user @var{commandname}
16076Display the @value{GDBN} commands used to define @var{commandname} (but
16077not its documentation). If no @var{commandname} is given, display the
16078definitions for all user-defined commands.
104c1213 16079
fcc73fe3 16080@cindex infinite recursion in user-defined commands
20f01a46
DH
16081@kindex show max-user-call-depth
16082@kindex set max-user-call-depth
16083@item show max-user-call-depth
5ca0cb28
DH
16084@itemx set max-user-call-depth
16085The value of @code{max-user-call-depth} controls how many recursion
16086levels are allowed in user-defined commands before GDB suspects an
16087infinite recursion and aborts the command.
104c1213
JM
16088@end table
16089
fcc73fe3
EZ
16090In addition to the above commands, user-defined commands frequently
16091use control flow commands, described in @ref{Command Files}.
16092
8e04817f
AC
16093When user-defined commands are executed, the
16094commands of the definition are not printed. An error in any command
16095stops execution of the user-defined command.
104c1213 16096
8e04817f
AC
16097If used interactively, commands that would ask for confirmation proceed
16098without asking when used inside a user-defined command. Many @value{GDBN}
16099commands that normally print messages to say what they are doing omit the
16100messages when used in a user-defined command.
104c1213 16101
8e04817f
AC
16102@node Hooks
16103@section User-defined command hooks
16104@cindex command hooks
16105@cindex hooks, for commands
16106@cindex hooks, pre-command
104c1213 16107
8e04817f 16108@kindex hook
8e04817f
AC
16109You may define @dfn{hooks}, which are a special kind of user-defined
16110command. Whenever you run the command @samp{foo}, if the user-defined
16111command @samp{hook-foo} exists, it is executed (with no arguments)
16112before that command.
104c1213 16113
8e04817f
AC
16114@cindex hooks, post-command
16115@kindex hookpost
8e04817f
AC
16116A hook may also be defined which is run after the command you executed.
16117Whenever you run the command @samp{foo}, if the user-defined command
16118@samp{hookpost-foo} exists, it is executed (with no arguments) after
16119that command. Post-execution hooks may exist simultaneously with
16120pre-execution hooks, for the same command.
104c1213 16121
8e04817f 16122It is valid for a hook to call the command which it hooks. If this
9f1c6395 16123occurs, the hook is not re-executed, thereby avoiding infinite recursion.
104c1213 16124
8e04817f
AC
16125@c It would be nice if hookpost could be passed a parameter indicating
16126@c if the command it hooks executed properly or not. FIXME!
104c1213 16127
8e04817f
AC
16128@kindex stop@r{, a pseudo-command}
16129In addition, a pseudo-command, @samp{stop} exists. Defining
16130(@samp{hook-stop}) makes the associated commands execute every time
16131execution stops in your program: before breakpoint commands are run,
16132displays are printed, or the stack frame is printed.
104c1213 16133
8e04817f
AC
16134For example, to ignore @code{SIGALRM} signals while
16135single-stepping, but treat them normally during normal execution,
16136you could define:
104c1213 16137
474c8240 16138@smallexample
8e04817f
AC
16139define hook-stop
16140handle SIGALRM nopass
16141end
104c1213 16142
8e04817f
AC
16143define hook-run
16144handle SIGALRM pass
16145end
104c1213 16146
8e04817f
AC
16147define hook-continue
16148handle SIGLARM pass
16149end
474c8240 16150@end smallexample
104c1213 16151
8e04817f 16152As a further example, to hook at the begining and end of the @code{echo}
b383017d 16153command, and to add extra text to the beginning and end of the message,
8e04817f 16154you could define:
104c1213 16155
474c8240 16156@smallexample
8e04817f
AC
16157define hook-echo
16158echo <<<---
16159end
104c1213 16160
8e04817f
AC
16161define hookpost-echo
16162echo --->>>\n
16163end
104c1213 16164
8e04817f
AC
16165(@value{GDBP}) echo Hello World
16166<<<---Hello World--->>>
16167(@value{GDBP})
104c1213 16168
474c8240 16169@end smallexample
104c1213 16170
8e04817f
AC
16171You can define a hook for any single-word command in @value{GDBN}, but
16172not for command aliases; you should define a hook for the basic command
c1468174 16173name, e.g.@: @code{backtrace} rather than @code{bt}.
8e04817f
AC
16174@c FIXME! So how does Joe User discover whether a command is an alias
16175@c or not?
16176If an error occurs during the execution of your hook, execution of
16177@value{GDBN} commands stops and @value{GDBN} issues a prompt
16178(before the command that you actually typed had a chance to run).
104c1213 16179
8e04817f
AC
16180If you try to define a hook which does not match any known command, you
16181get a warning from the @code{define} command.
c906108c 16182
8e04817f
AC
16183@node Command Files
16184@section Command files
c906108c 16185
8e04817f 16186@cindex command files
fcc73fe3 16187@cindex scripting commands
6fc08d32
EZ
16188A command file for @value{GDBN} is a text file made of lines that are
16189@value{GDBN} commands. Comments (lines starting with @kbd{#}) may
16190also be included. An empty line in a command file does nothing; it
16191does not mean to repeat the last command, as it would from the
16192terminal.
c906108c 16193
6fc08d32
EZ
16194You can request the execution of a command file with the @code{source}
16195command:
c906108c 16196
8e04817f
AC
16197@table @code
16198@kindex source
ca91424e 16199@cindex execute commands from a file
8e04817f
AC
16200@item source @var{filename}
16201Execute the command file @var{filename}.
c906108c
SS
16202@end table
16203
fcc73fe3
EZ
16204The lines in a command file are generally executed sequentially,
16205unless the order of execution is changed by one of the
16206@emph{flow-control commands} described below. The commands are not
a71ec265
DH
16207printed as they are executed. An error in any command terminates
16208execution of the command file and control is returned to the console.
c906108c 16209
4b505b12
AS
16210@value{GDBN} searches for @var{filename} in the current directory and then
16211on the search path (specified with the @samp{directory} command).
16212
8e04817f
AC
16213Commands that would ask for confirmation if used interactively proceed
16214without asking when used in a command file. Many @value{GDBN} commands that
16215normally print messages to say what they are doing omit the messages
16216when called from command files.
c906108c 16217
8e04817f
AC
16218@value{GDBN} also accepts command input from standard input. In this
16219mode, normal output goes to standard output and error output goes to
16220standard error. Errors in a command file supplied on standard input do
6fc08d32 16221not terminate execution of the command file---execution continues with
8e04817f 16222the next command.
c906108c 16223
474c8240 16224@smallexample
8e04817f 16225gdb < cmds > log 2>&1
474c8240 16226@end smallexample
c906108c 16227
8e04817f
AC
16228(The syntax above will vary depending on the shell used.) This example
16229will execute commands from the file @file{cmds}. All output and errors
16230would be directed to @file{log}.
c906108c 16231
fcc73fe3
EZ
16232Since commands stored on command files tend to be more general than
16233commands typed interactively, they frequently need to deal with
16234complicated situations, such as different or unexpected values of
16235variables and symbols, changes in how the program being debugged is
16236built, etc. @value{GDBN} provides a set of flow-control commands to
16237deal with these complexities. Using these commands, you can write
16238complex scripts that loop over data structures, execute commands
16239conditionally, etc.
16240
16241@table @code
16242@kindex if
16243@kindex else
16244@item if
16245@itemx else
16246This command allows to include in your script conditionally executed
16247commands. The @code{if} command takes a single argument, which is an
16248expression to evaluate. It is followed by a series of commands that
16249are executed only if the expression is true (its value is nonzero).
16250There can then optionally be an @code{else} line, followed by a series
16251of commands that are only executed if the expression was false. The
16252end of the list is marked by a line containing @code{end}.
16253
16254@kindex while
16255@item while
16256This command allows to write loops. Its syntax is similar to
16257@code{if}: the command takes a single argument, which is an expression
16258to evaluate, and must be followed by the commands to execute, one per
16259line, terminated by an @code{end}. These commands are called the
16260@dfn{body} of the loop. The commands in the body of @code{while} are
16261executed repeatedly as long as the expression evaluates to true.
16262
16263@kindex loop_break
16264@item loop_break
16265This command exits the @code{while} loop in whose body it is included.
16266Execution of the script continues after that @code{while}s @code{end}
16267line.
16268
16269@kindex loop_continue
16270@item loop_continue
16271This command skips the execution of the rest of the body of commands
16272in the @code{while} loop in whose body it is included. Execution
16273branches to the beginning of the @code{while} loop, where it evaluates
16274the controlling expression.
ca91424e
EZ
16275
16276@kindex end@r{ (if/else/while commands)}
16277@item end
16278Terminate the block of commands that are the body of @code{if},
16279@code{else}, or @code{while} flow-control commands.
fcc73fe3
EZ
16280@end table
16281
16282
8e04817f
AC
16283@node Output
16284@section Commands for controlled output
c906108c 16285
8e04817f
AC
16286During the execution of a command file or a user-defined command, normal
16287@value{GDBN} output is suppressed; the only output that appears is what is
16288explicitly printed by the commands in the definition. This section
16289describes three commands useful for generating exactly the output you
16290want.
c906108c
SS
16291
16292@table @code
8e04817f
AC
16293@kindex echo
16294@item echo @var{text}
16295@c I do not consider backslash-space a standard C escape sequence
16296@c because it is not in ANSI.
16297Print @var{text}. Nonprinting characters can be included in
16298@var{text} using C escape sequences, such as @samp{\n} to print a
16299newline. @strong{No newline is printed unless you specify one.}
16300In addition to the standard C escape sequences, a backslash followed
16301by a space stands for a space. This is useful for displaying a
16302string with spaces at the beginning or the end, since leading and
16303trailing spaces are otherwise trimmed from all arguments.
16304To print @samp{@w{ }and foo =@w{ }}, use the command
16305@samp{echo \@w{ }and foo = \@w{ }}.
c906108c 16306
8e04817f
AC
16307A backslash at the end of @var{text} can be used, as in C, to continue
16308the command onto subsequent lines. For example,
c906108c 16309
474c8240 16310@smallexample
8e04817f
AC
16311echo This is some text\n\
16312which is continued\n\
16313onto several lines.\n
474c8240 16314@end smallexample
c906108c 16315
8e04817f 16316produces the same output as
c906108c 16317
474c8240 16318@smallexample
8e04817f
AC
16319echo This is some text\n
16320echo which is continued\n
16321echo onto several lines.\n
474c8240 16322@end smallexample
c906108c 16323
8e04817f
AC
16324@kindex output
16325@item output @var{expression}
16326Print the value of @var{expression} and nothing but that value: no
16327newlines, no @samp{$@var{nn} = }. The value is not entered in the
16328value history either. @xref{Expressions, ,Expressions}, for more information
16329on expressions.
c906108c 16330
8e04817f
AC
16331@item output/@var{fmt} @var{expression}
16332Print the value of @var{expression} in format @var{fmt}. You can use
16333the same formats as for @code{print}. @xref{Output Formats,,Output
16334formats}, for more information.
c906108c 16335
8e04817f
AC
16336@kindex printf
16337@item printf @var{string}, @var{expressions}@dots{}
16338Print the values of the @var{expressions} under the control of
16339@var{string}. The @var{expressions} are separated by commas and may be
16340either numbers or pointers. Their values are printed as specified by
16341@var{string}, exactly as if your program were to execute the C
16342subroutine
16343@c FIXME: the above implies that at least all ANSI C formats are
16344@c supported, but it isn't true: %E and %G don't work (or so it seems).
16345@c Either this is a bug, or the manual should document what formats are
16346@c supported.
c906108c 16347
474c8240 16348@smallexample
8e04817f 16349printf (@var{string}, @var{expressions}@dots{});
474c8240 16350@end smallexample
c906108c 16351
8e04817f 16352For example, you can print two values in hex like this:
c906108c 16353
8e04817f
AC
16354@smallexample
16355printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo
16356@end smallexample
c906108c 16357
8e04817f
AC
16358The only backslash-escape sequences that you can use in the format
16359string are the simple ones that consist of backslash followed by a
16360letter.
c906108c
SS
16361@end table
16362
21c294e6
AC
16363@node Interpreters
16364@chapter Command Interpreters
16365@cindex command interpreters
16366
16367@value{GDBN} supports multiple command interpreters, and some command
16368infrastructure to allow users or user interface writers to switch
16369between interpreters or run commands in other interpreters.
16370
16371@value{GDBN} currently supports two command interpreters, the console
16372interpreter (sometimes called the command-line interpreter or @sc{cli})
16373and the machine interface interpreter (or @sc{gdb/mi}). This manual
16374describes both of these interfaces in great detail.
16375
16376By default, @value{GDBN} will start with the console interpreter.
16377However, the user may choose to start @value{GDBN} with another
16378interpreter by specifying the @option{-i} or @option{--interpreter}
16379startup options. Defined interpreters include:
16380
16381@table @code
16382@item console
16383@cindex console interpreter
16384The traditional console or command-line interpreter. This is the most often
16385used interpreter with @value{GDBN}. With no interpreter specified at runtime,
16386@value{GDBN} will use this interpreter.
16387
16388@item mi
16389@cindex mi interpreter
16390The newest @sc{gdb/mi} interface (currently @code{mi2}). Used primarily
16391by programs wishing to use @value{GDBN} as a backend for a debugger GUI
16392or an IDE. For more information, see @ref{GDB/MI, ,The @sc{gdb/mi}
16393Interface}.
16394
16395@item mi2
16396@cindex mi2 interpreter
16397The current @sc{gdb/mi} interface.
16398
16399@item mi1
16400@cindex mi1 interpreter
16401The @sc{gdb/mi} interface included in @value{GDBN} 5.1, 5.2, and 5.3.
16402
16403@end table
16404
16405@cindex invoke another interpreter
16406The interpreter being used by @value{GDBN} may not be dynamically
16407switched at runtime. Although possible, this could lead to a very
16408precarious situation. Consider an IDE using @sc{gdb/mi}. If a user
16409enters the command "interpreter-set console" in a console view,
16410@value{GDBN} would switch to using the console interpreter, rendering
16411the IDE inoperable!
16412
16413@kindex interpreter-exec
16414Although you may only choose a single interpreter at startup, you may execute
16415commands in any interpreter from the current interpreter using the appropriate
16416command. If you are running the console interpreter, simply use the
16417@code{interpreter-exec} command:
16418
16419@smallexample
16420interpreter-exec mi "-data-list-register-names"
16421@end smallexample
16422
16423@sc{gdb/mi} has a similar command, although it is only available in versions of
16424@value{GDBN} which support @sc{gdb/mi} version 2 (or greater).
16425
8e04817f
AC
16426@node TUI
16427@chapter @value{GDBN} Text User Interface
16428@cindex TUI
d0d5df6f 16429@cindex Text User Interface
c906108c 16430
8e04817f
AC
16431@menu
16432* TUI Overview:: TUI overview
16433* TUI Keys:: TUI key bindings
7cf36c78 16434* TUI Single Key Mode:: TUI single key mode
8e04817f
AC
16435* TUI Commands:: TUI specific commands
16436* TUI Configuration:: TUI configuration variables
16437@end menu
c906108c 16438
d0d5df6f
AC
16439The @value{GDBN} Text User Interface, TUI in short, is a terminal
16440interface which uses the @code{curses} library to show the source
16441file, the assembly output, the program registers and @value{GDBN}
16442commands in separate text windows.
16443
16444The TUI is enabled by invoking @value{GDBN} using either
16445@pindex gdbtui
16446@samp{gdbtui} or @samp{gdb -tui}.
c906108c 16447
8e04817f
AC
16448@node TUI Overview
16449@section TUI overview
c906108c 16450
8e04817f
AC
16451The TUI has two display modes that can be switched while
16452@value{GDBN} runs:
c906108c 16453
8e04817f
AC
16454@itemize @bullet
16455@item
16456A curses (or TUI) mode in which it displays several text
16457windows on the terminal.
c906108c 16458
8e04817f
AC
16459@item
16460A standard mode which corresponds to the @value{GDBN} configured without
16461the TUI.
16462@end itemize
c906108c 16463
8e04817f
AC
16464In the TUI mode, @value{GDBN} can display several text window
16465on the terminal:
c906108c 16466
8e04817f
AC
16467@table @emph
16468@item command
16469This window is the @value{GDBN} command window with the @value{GDBN}
16470prompt and the @value{GDBN} outputs. The @value{GDBN} input is still
16471managed using readline but through the TUI. The @emph{command}
16472window is always visible.
c906108c 16473
8e04817f
AC
16474@item source
16475The source window shows the source file of the program. The current
16476line as well as active breakpoints are displayed in this window.
c906108c 16477
8e04817f
AC
16478@item assembly
16479The assembly window shows the disassembly output of the program.
c906108c 16480
8e04817f
AC
16481@item register
16482This window shows the processor registers. It detects when
16483a register is changed and when this is the case, registers that have
6a1b180d 16484changed are highlighted.
c906108c 16485
c906108c
SS
16486@end table
16487
269c21fe
SC
16488The source and assembly windows show the current program position
16489by highlighting the current line and marking them with the @samp{>} marker.
16490Breakpoints are also indicated with two markers. A first one
16491indicates the breakpoint type:
16492
16493@table @code
16494@item B
16495Breakpoint which was hit at least once.
16496
16497@item b
16498Breakpoint which was never hit.
16499
16500@item H
16501Hardware breakpoint which was hit at least once.
16502
16503@item h
16504Hardware breakpoint which was never hit.
16505
16506@end table
16507
16508The second marker indicates whether the breakpoint is enabled or not:
16509
16510@table @code
16511@item +
16512Breakpoint is enabled.
16513
16514@item -
16515Breakpoint is disabled.
16516
16517@end table
16518
8e04817f
AC
16519The source, assembly and register windows are attached to the thread
16520and the frame position. They are updated when the current thread
16521changes, when the frame changes or when the program counter changes.
16522These three windows are arranged by the TUI according to several
16523layouts. The layout defines which of these three windows are visible.
16524The following layouts are available:
c906108c 16525
8e04817f
AC
16526@itemize @bullet
16527@item
16528source
2df3850c 16529
8e04817f
AC
16530@item
16531assembly
16532
16533@item
16534source and assembly
16535
16536@item
16537source and registers
c906108c 16538
8e04817f
AC
16539@item
16540assembly and registers
2df3850c 16541
8e04817f 16542@end itemize
c906108c 16543
b7bb15bc
SC
16544On top of the command window a status line gives various information
16545concerning the current process begin debugged. The status line is
16546updated when the information it shows changes. The following fields
16547are displayed:
16548
16549@table @emph
16550@item target
16551Indicates the current gdb target
16552(@pxref{Targets, ,Specifying a Debugging Target}).
16553
16554@item process
16555Gives information about the current process or thread number.
16556When no process is being debugged, this field is set to @code{No process}.
16557
16558@item function
16559Gives the current function name for the selected frame.
16560The name is demangled if demangling is turned on (@pxref{Print Settings}).
16561When there is no symbol corresponding to the current program counter
16562the string @code{??} is displayed.
16563
16564@item line
16565Indicates the current line number for the selected frame.
16566When the current line number is not known the string @code{??} is displayed.
16567
16568@item pc
16569Indicates the current program counter address.
16570
16571@end table
16572
8e04817f
AC
16573@node TUI Keys
16574@section TUI Key Bindings
16575@cindex TUI key bindings
c906108c 16576
8e04817f
AC
16577The TUI installs several key bindings in the readline keymaps
16578(@pxref{Command Line Editing}).
16579They allow to leave or enter in the TUI mode or they operate
7cf36c78
SC
16580directly on the TUI layout and windows. The TUI also provides
16581a @emph{SingleKey} keymap which binds several keys directly to
16582@value{GDBN} commands. The following key bindings
8e04817f 16583are installed for both TUI mode and the @value{GDBN} standard mode.
c906108c 16584
8e04817f
AC
16585@table @kbd
16586@kindex C-x C-a
16587@item C-x C-a
16588@kindex C-x a
16589@itemx C-x a
16590@kindex C-x A
16591@itemx C-x A
16592Enter or leave the TUI mode. When the TUI mode is left,
16593the curses window management is left and @value{GDBN} operates using
16594its standard mode writing on the terminal directly. When the TUI
16595mode is entered, the control is given back to the curses windows.
16596The screen is then refreshed.
c906108c 16597
8e04817f
AC
16598@kindex C-x 1
16599@item C-x 1
16600Use a TUI layout with only one window. The layout will
16601either be @samp{source} or @samp{assembly}. When the TUI mode
16602is not active, it will switch to the TUI mode.
2df3850c 16603
8e04817f 16604Think of this key binding as the Emacs @kbd{C-x 1} binding.
c906108c 16605
8e04817f
AC
16606@kindex C-x 2
16607@item C-x 2
16608Use a TUI layout with at least two windows. When the current
16609layout shows already two windows, a next layout with two windows is used.
16610When a new layout is chosen, one window will always be common to the
16611previous layout and the new one.
c906108c 16612
8e04817f 16613Think of it as the Emacs @kbd{C-x 2} binding.
2df3850c 16614
72ffddc9
SC
16615@kindex C-x o
16616@item C-x o
16617Change the active window. The TUI associates several key bindings
16618(like scrolling and arrow keys) to the active window. This command
16619gives the focus to the next TUI window.
16620
16621Think of it as the Emacs @kbd{C-x o} binding.
16622
7cf36c78
SC
16623@kindex C-x s
16624@item C-x s
16625Use the TUI @emph{SingleKey} keymap that binds single key to gdb commands
16626(@pxref{TUI Single Key Mode}).
16627
c906108c
SS
16628@end table
16629
8e04817f 16630The following key bindings are handled only by the TUI mode:
5d161b24 16631
8e04817f
AC
16632@table @key
16633@kindex PgUp
16634@item PgUp
16635Scroll the active window one page up.
c906108c 16636
8e04817f
AC
16637@kindex PgDn
16638@item PgDn
16639Scroll the active window one page down.
c906108c 16640
8e04817f
AC
16641@kindex Up
16642@item Up
16643Scroll the active window one line up.
c906108c 16644
8e04817f
AC
16645@kindex Down
16646@item Down
16647Scroll the active window one line down.
c906108c 16648
8e04817f
AC
16649@kindex Left
16650@item Left
16651Scroll the active window one column left.
c906108c 16652
8e04817f
AC
16653@kindex Right
16654@item Right
16655Scroll the active window one column right.
c906108c 16656
8e04817f
AC
16657@kindex C-L
16658@item C-L
16659Refresh the screen.
c906108c 16660
8e04817f 16661@end table
c906108c 16662
8e04817f 16663In the TUI mode, the arrow keys are used by the active window
72ffddc9
SC
16664for scrolling. This means they are available for readline when the
16665active window is the command window. When the command window
16666does not have the focus, it is necessary to use other readline
16667key bindings such as @key{C-p}, @key{C-n}, @key{C-b} and @key{C-f}.
8e04817f 16668
7cf36c78
SC
16669@node TUI Single Key Mode
16670@section TUI Single Key Mode
16671@cindex TUI single key mode
16672
16673The TUI provides a @emph{SingleKey} mode in which it installs a particular
16674key binding in the readline keymaps to connect single keys to
b383017d 16675some gdb commands.
7cf36c78
SC
16676
16677@table @kbd
16678@kindex c @r{(SingleKey TUI key)}
16679@item c
16680continue
16681
16682@kindex d @r{(SingleKey TUI key)}
16683@item d
16684down
16685
16686@kindex f @r{(SingleKey TUI key)}
16687@item f
16688finish
16689
16690@kindex n @r{(SingleKey TUI key)}
16691@item n
16692next
16693
16694@kindex q @r{(SingleKey TUI key)}
16695@item q
16696exit the @emph{SingleKey} mode.
16697
16698@kindex r @r{(SingleKey TUI key)}
16699@item r
16700run
16701
16702@kindex s @r{(SingleKey TUI key)}
16703@item s
16704step
16705
16706@kindex u @r{(SingleKey TUI key)}
16707@item u
16708up
16709
16710@kindex v @r{(SingleKey TUI key)}
16711@item v
16712info locals
16713
16714@kindex w @r{(SingleKey TUI key)}
16715@item w
16716where
16717
16718@end table
16719
16720Other keys temporarily switch to the @value{GDBN} command prompt.
16721The key that was pressed is inserted in the editing buffer so that
16722it is possible to type most @value{GDBN} commands without interaction
16723with the TUI @emph{SingleKey} mode. Once the command is entered the TUI
16724@emph{SingleKey} mode is restored. The only way to permanently leave
16725this mode is by hitting @key{q} or @samp{@key{C-x} @key{s}}.
16726
16727
8e04817f
AC
16728@node TUI Commands
16729@section TUI specific commands
16730@cindex TUI commands
16731
16732The TUI has specific commands to control the text windows.
16733These commands are always available, that is they do not depend on
16734the current terminal mode in which @value{GDBN} runs. When @value{GDBN}
16735is in the standard mode, using these commands will automatically switch
16736in the TUI mode.
c906108c
SS
16737
16738@table @code
3d757584
SC
16739@item info win
16740@kindex info win
16741List and give the size of all displayed windows.
16742
8e04817f 16743@item layout next
4644b6e3 16744@kindex layout
8e04817f 16745Display the next layout.
2df3850c 16746
8e04817f 16747@item layout prev
8e04817f 16748Display the previous layout.
c906108c 16749
8e04817f 16750@item layout src
8e04817f 16751Display the source window only.
c906108c 16752
8e04817f 16753@item layout asm
8e04817f 16754Display the assembly window only.
c906108c 16755
8e04817f 16756@item layout split
8e04817f 16757Display the source and assembly window.
c906108c 16758
8e04817f 16759@item layout regs
8e04817f
AC
16760Display the register window together with the source or assembly window.
16761
16762@item focus next | prev | src | asm | regs | split
16763@kindex focus
16764Set the focus to the named window.
16765This command allows to change the active window so that scrolling keys
16766can be affected to another window.
c906108c 16767
8e04817f
AC
16768@item refresh
16769@kindex refresh
16770Refresh the screen. This is similar to using @key{C-L} key.
c906108c 16771
6a1b180d
SC
16772@item tui reg float
16773@kindex tui reg
16774Show the floating point registers in the register window.
16775
16776@item tui reg general
16777Show the general registers in the register window.
16778
16779@item tui reg next
16780Show the next register group. The list of register groups as well as
16781their order is target specific. The predefined register groups are the
16782following: @code{general}, @code{float}, @code{system}, @code{vector},
16783@code{all}, @code{save}, @code{restore}.
16784
16785@item tui reg system
16786Show the system registers in the register window.
16787
8e04817f
AC
16788@item update
16789@kindex update
16790Update the source window and the current execution point.
c906108c 16791
8e04817f
AC
16792@item winheight @var{name} +@var{count}
16793@itemx winheight @var{name} -@var{count}
16794@kindex winheight
16795Change the height of the window @var{name} by @var{count}
16796lines. Positive counts increase the height, while negative counts
16797decrease it.
2df3850c 16798
c45da7e6
EZ
16799@item tabset
16800@kindex tabset @var{nchars}
16801Set the width of tab stops to be @var{nchars} characters.
16802
c906108c
SS
16803@end table
16804
8e04817f
AC
16805@node TUI Configuration
16806@section TUI configuration variables
16807@cindex TUI configuration variables
c906108c 16808
8e04817f
AC
16809The TUI has several configuration variables that control the
16810appearance of windows on the terminal.
c906108c 16811
8e04817f
AC
16812@table @code
16813@item set tui border-kind @var{kind}
16814@kindex set tui border-kind
16815Select the border appearance for the source, assembly and register windows.
16816The possible values are the following:
16817@table @code
16818@item space
16819Use a space character to draw the border.
c906108c 16820
8e04817f
AC
16821@item ascii
16822Use ascii characters + - and | to draw the border.
c906108c 16823
8e04817f
AC
16824@item acs
16825Use the Alternate Character Set to draw the border. The border is
16826drawn using character line graphics if the terminal supports them.
c78b4128 16827
8e04817f 16828@end table
c78b4128 16829
8e04817f
AC
16830@item set tui active-border-mode @var{mode}
16831@kindex set tui active-border-mode
16832Select the attributes to display the border of the active window.
16833The possible values are @code{normal}, @code{standout}, @code{reverse},
16834@code{half}, @code{half-standout}, @code{bold} and @code{bold-standout}.
c78b4128 16835
8e04817f
AC
16836@item set tui border-mode @var{mode}
16837@kindex set tui border-mode
16838Select the attributes to display the border of other windows.
16839The @var{mode} can be one of the following:
16840@table @code
16841@item normal
16842Use normal attributes to display the border.
c906108c 16843
8e04817f
AC
16844@item standout
16845Use standout mode.
c906108c 16846
8e04817f
AC
16847@item reverse
16848Use reverse video mode.
c906108c 16849
8e04817f
AC
16850@item half
16851Use half bright mode.
c906108c 16852
8e04817f
AC
16853@item half-standout
16854Use half bright and standout mode.
c906108c 16855
8e04817f
AC
16856@item bold
16857Use extra bright or bold mode.
c78b4128 16858
8e04817f
AC
16859@item bold-standout
16860Use extra bright or bold and standout mode.
c78b4128 16861
8e04817f 16862@end table
c78b4128 16863
8e04817f 16864@end table
c78b4128 16865
8e04817f
AC
16866@node Emacs
16867@chapter Using @value{GDBN} under @sc{gnu} Emacs
c78b4128 16868
8e04817f
AC
16869@cindex Emacs
16870@cindex @sc{gnu} Emacs
16871A special interface allows you to use @sc{gnu} Emacs to view (and
16872edit) the source files for the program you are debugging with
16873@value{GDBN}.
c906108c 16874
8e04817f
AC
16875To use this interface, use the command @kbd{M-x gdb} in Emacs. Give the
16876executable file you want to debug as an argument. This command starts
16877@value{GDBN} as a subprocess of Emacs, with input and output through a newly
16878created Emacs buffer.
16879@c (Do not use the @code{-tui} option to run @value{GDBN} from Emacs.)
c906108c 16880
8e04817f
AC
16881Using @value{GDBN} under Emacs is just like using @value{GDBN} normally except for two
16882things:
c906108c 16883
8e04817f
AC
16884@itemize @bullet
16885@item
16886All ``terminal'' input and output goes through the Emacs buffer.
16887@end itemize
c906108c 16888
8e04817f
AC
16889This applies both to @value{GDBN} commands and their output, and to the input
16890and output done by the program you are debugging.
bf0184be 16891
8e04817f
AC
16892This is useful because it means that you can copy the text of previous
16893commands and input them again; you can even use parts of the output
16894in this way.
bf0184be 16895
8e04817f
AC
16896All the facilities of Emacs' Shell mode are available for interacting
16897with your program. In particular, you can send signals the usual
16898way---for example, @kbd{C-c C-c} for an interrupt, @kbd{C-c C-z} for a
16899stop.
bf0184be 16900
8e04817f 16901@itemize @bullet
bf0184be 16902@item
8e04817f
AC
16903@value{GDBN} displays source code through Emacs.
16904@end itemize
bf0184be 16905
8e04817f
AC
16906Each time @value{GDBN} displays a stack frame, Emacs automatically finds the
16907source file for that frame and puts an arrow (@samp{=>}) at the
16908left margin of the current line. Emacs uses a separate buffer for
16909source display, and splits the screen to show both your @value{GDBN} session
16910and the source.
bf0184be 16911
8e04817f
AC
16912Explicit @value{GDBN} @code{list} or search commands still produce output as
16913usual, but you probably have no reason to use them from Emacs.
c906108c 16914
64fabec2
AC
16915If you specify an absolute file name when prompted for the @kbd{M-x
16916gdb} argument, then Emacs sets your current working directory to where
16917your program resides. If you only specify the file name, then Emacs
16918sets your current working directory to to the directory associated
16919with the previous buffer. In this case, @value{GDBN} may find your
16920program by searching your environment's @code{PATH} variable, but on
16921some operating systems it might not find the source. So, although the
16922@value{GDBN} input and output session proceeds normally, the auxiliary
16923buffer does not display the current source and line of execution.
16924
16925The initial working directory of @value{GDBN} is printed on the top
16926line of the @value{GDBN} I/O buffer and this serves as a default for
16927the commands that specify files for @value{GDBN} to operate
16928on. @xref{Files, ,Commands to specify files}.
16929
16930By default, @kbd{M-x gdb} calls the program called @file{gdb}. If you
16931need to call @value{GDBN} by a different name (for example, if you
16932keep several configurations around, with different names) you can
16933customize the Emacs variable @code{gud-gdb-command-name} to run the
16934one you want.
8e04817f
AC
16935
16936In the @value{GDBN} I/O buffer, you can use these special Emacs commands in
16937addition to the standard Shell mode commands:
c906108c 16938
8e04817f
AC
16939@table @kbd
16940@item C-h m
16941Describe the features of Emacs' @value{GDBN} Mode.
c906108c 16942
64fabec2 16943@item C-c C-s
8e04817f
AC
16944Execute to another source line, like the @value{GDBN} @code{step} command; also
16945update the display window to show the current file and location.
c906108c 16946
64fabec2 16947@item C-c C-n
8e04817f
AC
16948Execute to next source line in this function, skipping all function
16949calls, like the @value{GDBN} @code{next} command. Then update the display window
16950to show the current file and location.
c906108c 16951
64fabec2 16952@item C-c C-i
8e04817f
AC
16953Execute one instruction, like the @value{GDBN} @code{stepi} command; update
16954display window accordingly.
c906108c 16955
8e04817f
AC
16956@item C-c C-f
16957Execute until exit from the selected stack frame, like the @value{GDBN}
16958@code{finish} command.
c906108c 16959
64fabec2 16960@item C-c C-r
8e04817f
AC
16961Continue execution of your program, like the @value{GDBN} @code{continue}
16962command.
b433d00b 16963
64fabec2 16964@item C-c <
8e04817f
AC
16965Go up the number of frames indicated by the numeric argument
16966(@pxref{Arguments, , Numeric Arguments, Emacs, The @sc{gnu} Emacs Manual}),
16967like the @value{GDBN} @code{up} command.
b433d00b 16968
64fabec2 16969@item C-c >
8e04817f
AC
16970Go down the number of frames indicated by the numeric argument, like the
16971@value{GDBN} @code{down} command.
8e04817f 16972@end table
c906108c 16973
64fabec2 16974In any source file, the Emacs command @kbd{C-x SPC} (@code{gud-break})
8e04817f 16975tells @value{GDBN} to set a breakpoint on the source line point is on.
c906108c 16976
64fabec2
AC
16977If you type @kbd{M-x speedbar}, then Emacs displays a separate frame which
16978shows a backtrace when the @value{GDBN} I/O buffer is current. Move
16979point to any frame in the stack and type @key{RET} to make it become the
16980current frame and display the associated source in the source buffer.
16981Alternatively, click @kbd{Mouse-2} to make the selected frame become the
16982current one.
16983
8e04817f
AC
16984If you accidentally delete the source-display buffer, an easy way to get
16985it back is to type the command @code{f} in the @value{GDBN} buffer, to
16986request a frame display; when you run under Emacs, this recreates
16987the source buffer if necessary to show you the context of the current
16988frame.
c906108c 16989
8e04817f
AC
16990The source files displayed in Emacs are in ordinary Emacs buffers
16991which are visiting the source files in the usual way. You can edit
16992the files with these buffers if you wish; but keep in mind that @value{GDBN}
16993communicates with Emacs in terms of line numbers. If you add or
16994delete lines from the text, the line numbers that @value{GDBN} knows cease
16995to correspond properly with the code.
b383017d 16996
64fabec2
AC
16997The description given here is for GNU Emacs version 21.3 and a more
16998detailed description of its interaction with @value{GDBN} is given in
16999the Emacs manual (@pxref{Debuggers,,, Emacs, The @sc{gnu} Emacs Manual}).
c906108c 17000
8e04817f
AC
17001@c The following dropped because Epoch is nonstandard. Reactivate
17002@c if/when v19 does something similar. ---doc@cygnus.com 19dec1990
17003@ignore
17004@kindex Emacs Epoch environment
17005@kindex Epoch
17006@kindex inspect
c906108c 17007
8e04817f
AC
17008Version 18 of @sc{gnu} Emacs has a built-in window system
17009called the @code{epoch}
17010environment. Users of this environment can use a new command,
17011@code{inspect} which performs identically to @code{print} except that
17012each value is printed in its own window.
17013@end ignore
c906108c 17014
922fbb7b
AC
17015
17016@node GDB/MI
17017@chapter The @sc{gdb/mi} Interface
17018
17019@unnumberedsec Function and Purpose
17020
17021@cindex @sc{gdb/mi}, its purpose
6b5e8c01
NR
17022@sc{gdb/mi} is a line based machine oriented text interface to
17023@value{GDBN} and is activated by specifying using the
17024@option{--interpreter} command line option (@pxref{Mode Options}). It
17025is specifically intended to support the development of systems which
17026use the debugger as just one small component of a larger system.
922fbb7b
AC
17027
17028This chapter is a specification of the @sc{gdb/mi} interface. It is written
17029in the form of a reference manual.
17030
17031Note that @sc{gdb/mi} is still under construction, so some of the
17032features described below are incomplete and subject to change.
17033
17034@unnumberedsec Notation and Terminology
17035
17036@cindex notational conventions, for @sc{gdb/mi}
17037This chapter uses the following notation:
17038
17039@itemize @bullet
17040@item
17041@code{|} separates two alternatives.
17042
17043@item
17044@code{[ @var{something} ]} indicates that @var{something} is optional:
17045it may or may not be given.
17046
17047@item
17048@code{( @var{group} )*} means that @var{group} inside the parentheses
17049may repeat zero or more times.
17050
17051@item
17052@code{( @var{group} )+} means that @var{group} inside the parentheses
17053may repeat one or more times.
17054
17055@item
17056@code{"@var{string}"} means a literal @var{string}.
17057@end itemize
17058
17059@ignore
17060@heading Dependencies
17061@end ignore
17062
17063@heading Acknowledgments
17064
17065In alphabetic order: Andrew Cagney, Fernando Nasser, Stan Shebs and
17066Elena Zannoni.
17067
17068@menu
17069* GDB/MI Command Syntax::
17070* GDB/MI Compatibility with CLI::
17071* GDB/MI Output Records::
17072* GDB/MI Command Description Format::
17073* GDB/MI Breakpoint Table Commands::
17074* GDB/MI Data Manipulation::
17075* GDB/MI Program Control::
17076* GDB/MI Miscellaneous Commands::
17077@ignore
17078* GDB/MI Kod Commands::
17079* GDB/MI Memory Overlay Commands::
17080* GDB/MI Signal Handling Commands::
17081@end ignore
17082* GDB/MI Stack Manipulation::
17083* GDB/MI Symbol Query::
17084* GDB/MI Target Manipulation::
17085* GDB/MI Thread Commands::
17086* GDB/MI Tracepoint Commands::
17087* GDB/MI Variable Objects::
17088@end menu
17089
17090@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
17091@node GDB/MI Command Syntax
17092@section @sc{gdb/mi} Command Syntax
17093
17094@menu
17095* GDB/MI Input Syntax::
17096* GDB/MI Output Syntax::
17097* GDB/MI Simple Examples::
17098@end menu
17099
17100@node GDB/MI Input Syntax
17101@subsection @sc{gdb/mi} Input Syntax
17102
17103@cindex input syntax for @sc{gdb/mi}
17104@cindex @sc{gdb/mi}, input syntax
17105@table @code
17106@item @var{command} @expansion{}
17107@code{@var{cli-command} | @var{mi-command}}
17108
17109@item @var{cli-command} @expansion{}
17110@code{[ @var{token} ] @var{cli-command} @var{nl}}, where
17111@var{cli-command} is any existing @value{GDBN} CLI command.
17112
17113@item @var{mi-command} @expansion{}
17114@code{[ @var{token} ] "-" @var{operation} ( " " @var{option} )*
17115@code{[} " --" @code{]} ( " " @var{parameter} )* @var{nl}}
17116
17117@item @var{token} @expansion{}
17118"any sequence of digits"
17119
17120@item @var{option} @expansion{}
17121@code{"-" @var{parameter} [ " " @var{parameter} ]}
17122
17123@item @var{parameter} @expansion{}
17124@code{@var{non-blank-sequence} | @var{c-string}}
17125
17126@item @var{operation} @expansion{}
17127@emph{any of the operations described in this chapter}
17128
17129@item @var{non-blank-sequence} @expansion{}
17130@emph{anything, provided it doesn't contain special characters such as
17131"-", @var{nl}, """ and of course " "}
17132
17133@item @var{c-string} @expansion{}
17134@code{""" @var{seven-bit-iso-c-string-content} """}
17135
17136@item @var{nl} @expansion{}
17137@code{CR | CR-LF}
17138@end table
17139
17140@noindent
17141Notes:
17142
17143@itemize @bullet
17144@item
17145The CLI commands are still handled by the @sc{mi} interpreter; their
17146output is described below.
17147
17148@item
17149The @code{@var{token}}, when present, is passed back when the command
17150finishes.
17151
17152@item
17153Some @sc{mi} commands accept optional arguments as part of the parameter
17154list. Each option is identified by a leading @samp{-} (dash) and may be
17155followed by an optional argument parameter. Options occur first in the
17156parameter list and can be delimited from normal parameters using
17157@samp{--} (this is useful when some parameters begin with a dash).
17158@end itemize
17159
17160Pragmatics:
17161
17162@itemize @bullet
17163@item
17164We want easy access to the existing CLI syntax (for debugging).
17165
17166@item
17167We want it to be easy to spot a @sc{mi} operation.
17168@end itemize
17169
17170@node GDB/MI Output Syntax
17171@subsection @sc{gdb/mi} Output Syntax
17172
17173@cindex output syntax of @sc{gdb/mi}
17174@cindex @sc{gdb/mi}, output syntax
17175The output from @sc{gdb/mi} consists of zero or more out-of-band records
17176followed, optionally, by a single result record. This result record
17177is for the most recent command. The sequence of output records is
17178terminated by @samp{(@value{GDBP})}.
17179
17180If an input command was prefixed with a @code{@var{token}} then the
17181corresponding output for that command will also be prefixed by that same
17182@var{token}.
17183
17184@table @code
17185@item @var{output} @expansion{}
f7dc1244 17186@code{( @var{out-of-band-record} )* [ @var{result-record} ] "(@value{GDBP})" @var{nl}}
922fbb7b
AC
17187
17188@item @var{result-record} @expansion{}
17189@code{ [ @var{token} ] "^" @var{result-class} ( "," @var{result} )* @var{nl}}
17190
17191@item @var{out-of-band-record} @expansion{}
17192@code{@var{async-record} | @var{stream-record}}
17193
17194@item @var{async-record} @expansion{}
17195@code{@var{exec-async-output} | @var{status-async-output} | @var{notify-async-output}}
17196
17197@item @var{exec-async-output} @expansion{}
17198@code{[ @var{token} ] "*" @var{async-output}}
17199
17200@item @var{status-async-output} @expansion{}
17201@code{[ @var{token} ] "+" @var{async-output}}
17202
17203@item @var{notify-async-output} @expansion{}
17204@code{[ @var{token} ] "=" @var{async-output}}
17205
17206@item @var{async-output} @expansion{}
17207@code{@var{async-class} ( "," @var{result} )* @var{nl}}
17208
17209@item @var{result-class} @expansion{}
17210@code{"done" | "running" | "connected" | "error" | "exit"}
17211
17212@item @var{async-class} @expansion{}
17213@code{"stopped" | @var{others}} (where @var{others} will be added
17214depending on the needs---this is still in development).
17215
17216@item @var{result} @expansion{}
17217@code{ @var{variable} "=" @var{value}}
17218
17219@item @var{variable} @expansion{}
17220@code{ @var{string} }
17221
17222@item @var{value} @expansion{}
17223@code{ @var{const} | @var{tuple} | @var{list} }
17224
17225@item @var{const} @expansion{}
17226@code{@var{c-string}}
17227
17228@item @var{tuple} @expansion{}
17229@code{ "@{@}" | "@{" @var{result} ( "," @var{result} )* "@}" }
17230
17231@item @var{list} @expansion{}
17232@code{ "[]" | "[" @var{value} ( "," @var{value} )* "]" | "["
17233@var{result} ( "," @var{result} )* "]" }
17234
17235@item @var{stream-record} @expansion{}
17236@code{@var{console-stream-output} | @var{target-stream-output} | @var{log-stream-output}}
17237
17238@item @var{console-stream-output} @expansion{}
17239@code{"~" @var{c-string}}
17240
17241@item @var{target-stream-output} @expansion{}
17242@code{"@@" @var{c-string}}
17243
17244@item @var{log-stream-output} @expansion{}
17245@code{"&" @var{c-string}}
17246
17247@item @var{nl} @expansion{}
17248@code{CR | CR-LF}
17249
17250@item @var{token} @expansion{}
17251@emph{any sequence of digits}.
17252@end table
17253
17254@noindent
17255Notes:
17256
17257@itemize @bullet
17258@item
17259All output sequences end in a single line containing a period.
17260
17261@item
17262The @code{@var{token}} is from the corresponding request. If an execution
17263command is interrupted by the @samp{-exec-interrupt} command, the
17264@var{token} associated with the @samp{*stopped} message is the one of the
17265original execution command, not the one of the interrupt command.
17266
17267@item
17268@cindex status output in @sc{gdb/mi}
17269@var{status-async-output} contains on-going status information about the
17270progress of a slow operation. It can be discarded. All status output is
17271prefixed by @samp{+}.
17272
17273@item
17274@cindex async output in @sc{gdb/mi}
17275@var{exec-async-output} contains asynchronous state change on the target
17276(stopped, started, disappeared). All async output is prefixed by
17277@samp{*}.
17278
17279@item
17280@cindex notify output in @sc{gdb/mi}
17281@var{notify-async-output} contains supplementary information that the
17282client should handle (e.g., a new breakpoint information). All notify
17283output is prefixed by @samp{=}.
17284
17285@item
17286@cindex console output in @sc{gdb/mi}
17287@var{console-stream-output} is output that should be displayed as is in the
17288console. It is the textual response to a CLI command. All the console
17289output is prefixed by @samp{~}.
17290
17291@item
17292@cindex target output in @sc{gdb/mi}
17293@var{target-stream-output} is the output produced by the target program.
17294All the target output is prefixed by @samp{@@}.
17295
17296@item
17297@cindex log output in @sc{gdb/mi}
17298@var{log-stream-output} is output text coming from @value{GDBN}'s internals, for
17299instance messages that should be displayed as part of an error log. All
17300the log output is prefixed by @samp{&}.
17301
17302@item
17303@cindex list output in @sc{gdb/mi}
17304New @sc{gdb/mi} commands should only output @var{lists} containing
17305@var{values}.
17306
17307
17308@end itemize
17309
17310@xref{GDB/MI Stream Records, , @sc{gdb/mi} Stream Records}, for more
17311details about the various output records.
17312
17313@node GDB/MI Simple Examples
17314@subsection Simple Examples of @sc{gdb/mi} Interaction
17315@cindex @sc{gdb/mi}, simple examples
17316
17317This subsection presents several simple examples of interaction using
17318the @sc{gdb/mi} interface. In these examples, @samp{->} means that the
17319following line is passed to @sc{gdb/mi} as input, while @samp{<-} means
17320the output received from @sc{gdb/mi}.
17321
17322@subsubheading Target Stop
17323@c Ummm... There is no "-stop" command. This assumes async, no?
17324Here's an example of stopping the inferior process:
17325
17326@smallexample
17327-> -stop
17328<- (@value{GDBP})
17329@end smallexample
17330
17331@noindent
17332and later:
17333
17334@smallexample
17335<- *stop,reason="stop",address="0x123",source="a.c:123"
17336<- (@value{GDBP})
17337@end smallexample
17338
17339@subsubheading Simple CLI Command
17340
17341Here's an example of a simple CLI command being passed through
17342@sc{gdb/mi} and on to the CLI.
17343
17344@smallexample
17345-> print 1+2
17346<- &"print 1+2\n"
17347<- ~"$1 = 3\n"
17348<- ^done
17349<- (@value{GDBP})
17350@end smallexample
17351
17352@subsubheading Command With Side Effects
17353
17354@smallexample
17355-> -symbol-file xyz.exe
17356<- *breakpoint,nr="3",address="0x123",source="a.c:123"
17357<- (@value{GDBP})
17358@end smallexample
17359
17360@subsubheading A Bad Command
17361
17362Here's what happens if you pass a non-existent command:
17363
17364@smallexample
17365-> -rubbish
17366<- ^error,msg="Undefined MI command: rubbish"
17367<- (@value{GDBP})
17368@end smallexample
17369
17370@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
17371@node GDB/MI Compatibility with CLI
17372@section @sc{gdb/mi} Compatibility with CLI
17373
17374@cindex compatibility, @sc{gdb/mi} and CLI
17375@cindex @sc{gdb/mi}, compatibility with CLI
17376To help users familiar with @value{GDBN}'s existing CLI interface, @sc{gdb/mi}
17377accepts existing CLI commands. As specified by the syntax, such
17378commands can be directly entered into the @sc{gdb/mi} interface and @value{GDBN} will
17379respond.
17380
17381This mechanism is provided as an aid to developers of @sc{gdb/mi}
17382clients and not as a reliable interface into the CLI. Since the command
17383is being interpreteted in an environment that assumes @sc{gdb/mi}
17384behaviour, the exact output of such commands is likely to end up being
17385an un-supported hybrid of @sc{gdb/mi} and CLI output.
17386
17387@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
17388@node GDB/MI Output Records
17389@section @sc{gdb/mi} Output Records
17390
17391@menu
17392* GDB/MI Result Records::
17393* GDB/MI Stream Records::
17394* GDB/MI Out-of-band Records::
17395@end menu
17396
17397@node GDB/MI Result Records
17398@subsection @sc{gdb/mi} Result Records
17399
17400@cindex result records in @sc{gdb/mi}
17401@cindex @sc{gdb/mi}, result records
17402In addition to a number of out-of-band notifications, the response to a
17403@sc{gdb/mi} command includes one of the following result indications:
17404
17405@table @code
17406@findex ^done
17407@item "^done" [ "," @var{results} ]
17408The synchronous operation was successful, @code{@var{results}} are the return
17409values.
17410
17411@item "^running"
17412@findex ^running
17413@c Is this one correct? Should it be an out-of-band notification?
17414The asynchronous operation was successfully started. The target is
17415running.
17416
17417@item "^error" "," @var{c-string}
17418@findex ^error
17419The operation failed. The @code{@var{c-string}} contains the corresponding
17420error message.
17421@end table
17422
17423@node GDB/MI Stream Records
17424@subsection @sc{gdb/mi} Stream Records
17425
17426@cindex @sc{gdb/mi}, stream records
17427@cindex stream records in @sc{gdb/mi}
17428@value{GDBN} internally maintains a number of output streams: the console, the
17429target, and the log. The output intended for each of these streams is
17430funneled through the @sc{gdb/mi} interface using @dfn{stream records}.
17431
17432Each stream record begins with a unique @dfn{prefix character} which
17433identifies its stream (@pxref{GDB/MI Output Syntax, , @sc{gdb/mi} Output
17434Syntax}). In addition to the prefix, each stream record contains a
17435@code{@var{string-output}}. This is either raw text (with an implicit new
17436line) or a quoted C string (which does not contain an implicit newline).
17437
17438@table @code
17439@item "~" @var{string-output}
17440The console output stream contains text that should be displayed in the
17441CLI console window. It contains the textual responses to CLI commands.
17442
17443@item "@@" @var{string-output}
17444The target output stream contains any textual output from the running
17445target.
17446
17447@item "&" @var{string-output}
17448The log stream contains debugging messages being produced by @value{GDBN}'s
17449internals.
17450@end table
17451
17452@node GDB/MI Out-of-band Records
17453@subsection @sc{gdb/mi} Out-of-band Records
17454
17455@cindex out-of-band records in @sc{gdb/mi}
17456@cindex @sc{gdb/mi}, out-of-band records
17457@dfn{Out-of-band} records are used to notify the @sc{gdb/mi} client of
17458additional changes that have occurred. Those changes can either be a
17459consequence of @sc{gdb/mi} (e.g., a breakpoint modified) or a result of
17460target activity (e.g., target stopped).
17461
17462The following is a preliminary list of possible out-of-band records.
034dad6f 17463In particular, the @var{exec-async-output} records.
922fbb7b
AC
17464
17465@table @code
034dad6f
BR
17466@item *stopped,reason="@var{reason}"
17467@end table
17468
17469@var{reason} can be one of the following:
17470
17471@table @code
17472@item breakpoint-hit
17473A breakpoint was reached.
17474@item watchpoint-trigger
17475A watchpoint was triggered.
17476@item read-watchpoint-trigger
17477A read watchpoint was triggered.
17478@item access-watchpoint-trigger
17479An access watchpoint was triggered.
17480@item function-finished
17481An -exec-finish or similar CLI command was accomplished.
17482@item location-reached
17483An -exec-until or similar CLI command was accomplished.
17484@item watchpoint-scope
17485A watchpoint has gone out of scope.
17486@item end-stepping-range
17487An -exec-next, -exec-next-instruction, -exec-step, -exec-step-instruction or
17488similar CLI command was accomplished.
17489@item exited-signalled
17490The inferior exited because of a signal.
17491@item exited
17492The inferior exited.
17493@item exited-normally
17494The inferior exited normally.
17495@item signal-received
17496A signal was received by the inferior.
922fbb7b
AC
17497@end table
17498
17499
17500@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
17501@node GDB/MI Command Description Format
17502@section @sc{gdb/mi} Command Description Format
17503
17504The remaining sections describe blocks of commands. Each block of
17505commands is laid out in a fashion similar to this section.
17506
17507Note the the line breaks shown in the examples are here only for
17508readability. They don't appear in the real output.
17509Also note that the commands with a non-available example (N.A.@:) are
17510not yet implemented.
17511
17512@subheading Motivation
17513
17514The motivation for this collection of commands.
17515
17516@subheading Introduction
17517
17518A brief introduction to this collection of commands as a whole.
17519
17520@subheading Commands
17521
17522For each command in the block, the following is described:
17523
17524@subsubheading Synopsis
17525
17526@smallexample
17527 -command @var{args}@dots{}
17528@end smallexample
17529
922fbb7b
AC
17530@subsubheading Result
17531
265eeb58 17532@subsubheading @value{GDBN} Command
922fbb7b 17533
265eeb58 17534The corresponding @value{GDBN} CLI command(s), if any.
922fbb7b
AC
17535
17536@subsubheading Example
17537
922fbb7b
AC
17538@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
17539@node GDB/MI Breakpoint Table Commands
17540@section @sc{gdb/mi} Breakpoint table commands
17541
17542@cindex breakpoint commands for @sc{gdb/mi}
17543@cindex @sc{gdb/mi}, breakpoint commands
17544This section documents @sc{gdb/mi} commands for manipulating
17545breakpoints.
17546
17547@subheading The @code{-break-after} Command
17548@findex -break-after
17549
17550@subsubheading Synopsis
17551
17552@smallexample
17553 -break-after @var{number} @var{count}
17554@end smallexample
17555
17556The breakpoint number @var{number} is not in effect until it has been
17557hit @var{count} times. To see how this is reflected in the output of
17558the @samp{-break-list} command, see the description of the
17559@samp{-break-list} command below.
17560
17561@subsubheading @value{GDBN} Command
17562
17563The corresponding @value{GDBN} command is @samp{ignore}.
17564
17565@subsubheading Example
17566
17567@smallexample
17568(@value{GDBP})
17569-break-insert main
948d5102
NR
17570^done,bkpt=@{number="1",addr="0x000100d0",file="hello.c",
17571fullname="/home/foo/hello.c",line="5",times="0"@}
922fbb7b
AC
17572(@value{GDBP})
17573-break-after 1 3
17574~
17575^done
17576(@value{GDBP})
17577-break-list
17578^done,BreakpointTable=@{nr_rows="1",nr_cols="6",
17579hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17580@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17581@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17582@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17583@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17584@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17585body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
948d5102
NR
17586addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c",
17587line="5",times="0",ignore="3"@}]@}
922fbb7b
AC
17588(@value{GDBP})
17589@end smallexample
17590
17591@ignore
17592@subheading The @code{-break-catch} Command
17593@findex -break-catch
17594
17595@subheading The @code{-break-commands} Command
17596@findex -break-commands
17597@end ignore
17598
17599
17600@subheading The @code{-break-condition} Command
17601@findex -break-condition
17602
17603@subsubheading Synopsis
17604
17605@smallexample
17606 -break-condition @var{number} @var{expr}
17607@end smallexample
17608
17609Breakpoint @var{number} will stop the program only if the condition in
17610@var{expr} is true. The condition becomes part of the
17611@samp{-break-list} output (see the description of the @samp{-break-list}
17612command below).
17613
17614@subsubheading @value{GDBN} Command
17615
17616The corresponding @value{GDBN} command is @samp{condition}.
17617
17618@subsubheading Example
17619
17620@smallexample
17621(@value{GDBP})
17622-break-condition 1 1
17623^done
17624(@value{GDBP})
17625-break-list
17626^done,BreakpointTable=@{nr_rows="1",nr_cols="6",
17627hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17628@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17629@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17630@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17631@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17632@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17633body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
948d5102
NR
17634addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c",
17635line="5",cond="1",times="0",ignore="3"@}]@}
922fbb7b
AC
17636(@value{GDBP})
17637@end smallexample
17638
17639@subheading The @code{-break-delete} Command
17640@findex -break-delete
17641
17642@subsubheading Synopsis
17643
17644@smallexample
17645 -break-delete ( @var{breakpoint} )+
17646@end smallexample
17647
17648Delete the breakpoint(s) whose number(s) are specified in the argument
17649list. This is obviously reflected in the breakpoint list.
17650
17651@subsubheading @value{GDBN} command
17652
17653The corresponding @value{GDBN} command is @samp{delete}.
17654
17655@subsubheading Example
17656
17657@smallexample
17658(@value{GDBP})
17659-break-delete 1
17660^done
17661(@value{GDBP})
17662-break-list
17663^done,BreakpointTable=@{nr_rows="0",nr_cols="6",
17664hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17665@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17666@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17667@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17668@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17669@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17670body=[]@}
17671(@value{GDBP})
17672@end smallexample
17673
17674@subheading The @code{-break-disable} Command
17675@findex -break-disable
17676
17677@subsubheading Synopsis
17678
17679@smallexample
17680 -break-disable ( @var{breakpoint} )+
17681@end smallexample
17682
17683Disable the named @var{breakpoint}(s). The field @samp{enabled} in the
17684break list is now set to @samp{n} for the named @var{breakpoint}(s).
17685
17686@subsubheading @value{GDBN} Command
17687
17688The corresponding @value{GDBN} command is @samp{disable}.
17689
17690@subsubheading Example
17691
17692@smallexample
17693(@value{GDBP})
17694-break-disable 2
17695^done
17696(@value{GDBP})
17697-break-list
17698^done,BreakpointTable=@{nr_rows="1",nr_cols="6",
17699hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17700@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17701@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17702@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17703@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17704@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17705body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="n",
948d5102
NR
17706addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c",
17707line="5",times="0"@}]@}
922fbb7b
AC
17708(@value{GDBP})
17709@end smallexample
17710
17711@subheading The @code{-break-enable} Command
17712@findex -break-enable
17713
17714@subsubheading Synopsis
17715
17716@smallexample
17717 -break-enable ( @var{breakpoint} )+
17718@end smallexample
17719
17720Enable (previously disabled) @var{breakpoint}(s).
17721
17722@subsubheading @value{GDBN} Command
17723
17724The corresponding @value{GDBN} command is @samp{enable}.
17725
17726@subsubheading Example
17727
17728@smallexample
17729(@value{GDBP})
17730-break-enable 2
17731^done
17732(@value{GDBP})
17733-break-list
17734^done,BreakpointTable=@{nr_rows="1",nr_cols="6",
17735hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17736@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17737@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17738@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17739@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17740@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17741body=[bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y",
948d5102
NR
17742addr="0x000100d0",func="main",file="hello.c",fullname="/home/foo/hello.c",
17743line="5",times="0"@}]@}
922fbb7b
AC
17744(@value{GDBP})
17745@end smallexample
17746
17747@subheading The @code{-break-info} Command
17748@findex -break-info
17749
17750@subsubheading Synopsis
17751
17752@smallexample
17753 -break-info @var{breakpoint}
17754@end smallexample
17755
17756@c REDUNDANT???
17757Get information about a single breakpoint.
17758
17759@subsubheading @value{GDBN} command
17760
17761The corresponding @value{GDBN} command is @samp{info break @var{breakpoint}}.
17762
17763@subsubheading Example
17764N.A.
17765
17766@subheading The @code{-break-insert} Command
17767@findex -break-insert
17768
17769@subsubheading Synopsis
17770
17771@smallexample
17772 -break-insert [ -t ] [ -h ] [ -r ]
17773 [ -c @var{condition} ] [ -i @var{ignore-count} ]
17774 [ -p @var{thread} ] [ @var{line} | @var{addr} ]
17775@end smallexample
17776
17777@noindent
17778If specified, @var{line}, can be one of:
17779
17780@itemize @bullet
17781@item function
17782@c @item +offset
17783@c @item -offset
17784@c @item linenum
17785@item filename:linenum
17786@item filename:function
17787@item *address
17788@end itemize
17789
17790The possible optional parameters of this command are:
17791
17792@table @samp
17793@item -t
948d5102 17794Insert a temporary breakpoint.
922fbb7b
AC
17795@item -h
17796Insert a hardware breakpoint.
17797@item -c @var{condition}
17798Make the breakpoint conditional on @var{condition}.
17799@item -i @var{ignore-count}
17800Initialize the @var{ignore-count}.
17801@item -r
17802Insert a regular breakpoint in all the functions whose names match the
17803given regular expression. Other flags are not applicable to regular
17804expresson.
17805@end table
17806
17807@subsubheading Result
17808
17809The result is in the form:
17810
17811@smallexample
948d5102
NR
17812^done,bkpt=@{number="@var{number}",type="@var{type}",disp="del"|"keep",
17813enabled="y"|"n",addr="@var{hex}",func="@var{funcname}",file="@var{filename}",
17814fullname="@var{full_filename}",line="@var{lineno}",times="@var{times}"@}
922fbb7b
AC
17815@end smallexample
17816
17817@noindent
948d5102
NR
17818where @var{number} is the @value{GDBN} number for this breakpoint,
17819@var{funcname} is the name of the function where the breakpoint was
17820inserted, @var{filename} is the name of the source file which contains
17821this function, @var{lineno} is the source line number within that file
17822and @var{times} the number of times that the breakpoint has been hit
17823(always 0 for -break-insert but may be greater for -break-info or -break-list
17824which use the same output).
922fbb7b
AC
17825
17826Note: this format is open to change.
17827@c An out-of-band breakpoint instead of part of the result?
17828
17829@subsubheading @value{GDBN} Command
17830
17831The corresponding @value{GDBN} commands are @samp{break}, @samp{tbreak},
17832@samp{hbreak}, @samp{thbreak}, and @samp{rbreak}.
17833
17834@subsubheading Example
17835
17836@smallexample
17837(@value{GDBP})
17838-break-insert main
948d5102
NR
17839^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c",
17840fullname="/home/foo/recursive2.c,line="4",times="0"@}
922fbb7b
AC
17841(@value{GDBP})
17842-break-insert -t foo
948d5102
NR
17843^done,bkpt=@{number="2",addr="0x00010774",file="recursive2.c",
17844fullname="/home/foo/recursive2.c,line="11",times="0"@}
922fbb7b
AC
17845(@value{GDBP})
17846-break-list
17847^done,BreakpointTable=@{nr_rows="2",nr_cols="6",
17848hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17849@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17850@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17851@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17852@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17853@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17854body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
948d5102
NR
17855addr="0x0001072c", func="main",file="recursive2.c",
17856fullname="/home/foo/recursive2.c,"line="4",times="0"@},
922fbb7b 17857bkpt=@{number="2",type="breakpoint",disp="del",enabled="y",
948d5102
NR
17858addr="0x00010774",func="foo",file="recursive2.c",
17859fullname="/home/foo/recursive2.c",line="11",times="0"@}]@}
922fbb7b
AC
17860(@value{GDBP})
17861-break-insert -r foo.*
17862~int foo(int, int);
948d5102
NR
17863^done,bkpt=@{number="3",addr="0x00010774",file="recursive2.c,
17864"fullname="/home/foo/recursive2.c",line="11",times="0"@}
922fbb7b
AC
17865(@value{GDBP})
17866@end smallexample
17867
17868@subheading The @code{-break-list} Command
17869@findex -break-list
17870
17871@subsubheading Synopsis
17872
17873@smallexample
17874 -break-list
17875@end smallexample
17876
17877Displays the list of inserted breakpoints, showing the following fields:
17878
17879@table @samp
17880@item Number
17881number of the breakpoint
17882@item Type
17883type of the breakpoint: @samp{breakpoint} or @samp{watchpoint}
17884@item Disposition
17885should the breakpoint be deleted or disabled when it is hit: @samp{keep}
17886or @samp{nokeep}
17887@item Enabled
17888is the breakpoint enabled or no: @samp{y} or @samp{n}
17889@item Address
17890memory location at which the breakpoint is set
17891@item What
17892logical location of the breakpoint, expressed by function name, file
17893name, line number
17894@item Times
17895number of times the breakpoint has been hit
17896@end table
17897
17898If there are no breakpoints or watchpoints, the @code{BreakpointTable}
17899@code{body} field is an empty list.
17900
17901@subsubheading @value{GDBN} Command
17902
17903The corresponding @value{GDBN} command is @samp{info break}.
17904
17905@subsubheading Example
17906
17907@smallexample
17908(@value{GDBP})
17909-break-list
17910^done,BreakpointTable=@{nr_rows="2",nr_cols="6",
17911hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17912@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17913@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17914@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17915@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17916@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17917body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
17918addr="0x000100d0",func="main",file="hello.c",line="5",times="0"@},
17919bkpt=@{number="2",type="breakpoint",disp="keep",enabled="y",
948d5102
NR
17920addr="0x00010114",func="foo",file="hello.c",fullname="/home/foo/hello.c",
17921line="13",times="0"@}]@}
922fbb7b
AC
17922(@value{GDBP})
17923@end smallexample
17924
17925Here's an example of the result when there are no breakpoints:
17926
17927@smallexample
17928(@value{GDBP})
17929-break-list
17930^done,BreakpointTable=@{nr_rows="0",nr_cols="6",
17931hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
17932@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
17933@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
17934@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
17935@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
17936@{width="40",alignment="2",col_name="what",colhdr="What"@}],
17937body=[]@}
17938(@value{GDBP})
17939@end smallexample
17940
17941@subheading The @code{-break-watch} Command
17942@findex -break-watch
17943
17944@subsubheading Synopsis
17945
17946@smallexample
17947 -break-watch [ -a | -r ]
17948@end smallexample
17949
17950Create a watchpoint. With the @samp{-a} option it will create an
17951@dfn{access} watchpoint, i.e. a watchpoint that triggers either on a
17952read from or on a write to the memory location. With the @samp{-r}
17953option, the watchpoint created is a @dfn{read} watchpoint, i.e. it will
17954trigger only when the memory location is accessed for reading. Without
17955either of the options, the watchpoint created is a regular watchpoint,
17956i.e. it will trigger when the memory location is accessed for writing.
17957@xref{Set Watchpoints, , Setting watchpoints}.
17958
17959Note that @samp{-break-list} will report a single list of watchpoints and
17960breakpoints inserted.
17961
17962@subsubheading @value{GDBN} Command
17963
17964The corresponding @value{GDBN} commands are @samp{watch}, @samp{awatch}, and
17965@samp{rwatch}.
17966
17967@subsubheading Example
17968
17969Setting a watchpoint on a variable in the @code{main} function:
17970
17971@smallexample
17972(@value{GDBP})
17973-break-watch x
17974^done,wpt=@{number="2",exp="x"@}
17975(@value{GDBP})
17976-exec-continue
17977^running
17978^done,reason="watchpoint-trigger",wpt=@{number="2",exp="x"@},
17979value=@{old="-268439212",new="55"@},
76ff342d 17980frame=@{func="main",args=[],file="recursive2.c",
948d5102 17981fullname="/home/foo/bar/recursive2.c",line="5"@}
922fbb7b
AC
17982(@value{GDBP})
17983@end smallexample
17984
17985Setting a watchpoint on a variable local to a function. @value{GDBN} will stop
17986the program execution twice: first for the variable changing value, then
17987for the watchpoint going out of scope.
17988
17989@smallexample
17990(@value{GDBP})
17991-break-watch C
17992^done,wpt=@{number="5",exp="C"@}
17993(@value{GDBP})
17994-exec-continue
17995^running
17996^done,reason="watchpoint-trigger",
17997wpt=@{number="5",exp="C"@},value=@{old="-276895068",new="3"@},
17998frame=@{func="callee4",args=[],
76ff342d
DJ
17999file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18000fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@}
922fbb7b
AC
18001(@value{GDBP})
18002-exec-continue
18003^running
18004^done,reason="watchpoint-scope",wpnum="5",
18005frame=@{func="callee3",args=[@{name="strarg",
18006value="0x11940 \"A string argument.\""@}],
76ff342d
DJ
18007file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18008fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@}
922fbb7b
AC
18009(@value{GDBP})
18010@end smallexample
18011
18012Listing breakpoints and watchpoints, at different points in the program
18013execution. Note that once the watchpoint goes out of scope, it is
18014deleted.
18015
18016@smallexample
18017(@value{GDBP})
18018-break-watch C
18019^done,wpt=@{number="2",exp="C"@}
18020(@value{GDBP})
18021-break-list
18022^done,BreakpointTable=@{nr_rows="2",nr_cols="6",
18023hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
18024@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
18025@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
18026@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
18027@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
18028@{width="40",alignment="2",col_name="what",colhdr="What"@}],
18029body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
18030addr="0x00010734",func="callee4",
948d5102
NR
18031file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18032fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c"line="8",times="1"@},
922fbb7b
AC
18033bkpt=@{number="2",type="watchpoint",disp="keep",
18034enabled="y",addr="",what="C",times="0"@}]@}
18035(@value{GDBP})
18036-exec-continue
18037^running
18038^done,reason="watchpoint-trigger",wpt=@{number="2",exp="C"@},
18039value=@{old="-276895068",new="3"@},
18040frame=@{func="callee4",args=[],
76ff342d
DJ
18041file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18042fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="13"@}
922fbb7b
AC
18043(@value{GDBP})
18044-break-list
18045^done,BreakpointTable=@{nr_rows="2",nr_cols="6",
18046hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
18047@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
18048@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
18049@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
18050@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
18051@{width="40",alignment="2",col_name="what",colhdr="What"@}],
18052body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
18053addr="0x00010734",func="callee4",
948d5102
NR
18054file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18055fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8",times="1"@},
922fbb7b
AC
18056bkpt=@{number="2",type="watchpoint",disp="keep",
18057enabled="y",addr="",what="C",times="-5"@}]@}
18058(@value{GDBP})
18059-exec-continue
18060^running
18061^done,reason="watchpoint-scope",wpnum="2",
18062frame=@{func="callee3",args=[@{name="strarg",
18063value="0x11940 \"A string argument.\""@}],
76ff342d
DJ
18064file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18065fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@}
922fbb7b
AC
18066(@value{GDBP})
18067-break-list
18068^done,BreakpointTable=@{nr_rows="1",nr_cols="6",
18069hdr=[@{width="3",alignment="-1",col_name="number",colhdr="Num"@},
18070@{width="14",alignment="-1",col_name="type",colhdr="Type"@},
18071@{width="4",alignment="-1",col_name="disp",colhdr="Disp"@},
18072@{width="3",alignment="-1",col_name="enabled",colhdr="Enb"@},
18073@{width="10",alignment="-1",col_name="addr",colhdr="Address"@},
18074@{width="40",alignment="2",col_name="what",colhdr="What"@}],
18075body=[bkpt=@{number="1",type="breakpoint",disp="keep",enabled="y",
18076addr="0x00010734",func="callee4",
948d5102
NR
18077file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
18078fullname="/home/foo/devo/gdb/testsuite/gdb.mi/basics.c",line="8",
18079times="1"@}]@}
922fbb7b
AC
18080(@value{GDBP})
18081@end smallexample
18082
18083@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
18084@node GDB/MI Data Manipulation
18085@section @sc{gdb/mi} Data Manipulation
18086
18087@cindex data manipulation, in @sc{gdb/mi}
18088@cindex @sc{gdb/mi}, data manipulation
18089This section describes the @sc{gdb/mi} commands that manipulate data:
18090examine memory and registers, evaluate expressions, etc.
18091
18092@c REMOVED FROM THE INTERFACE.
18093@c @subheading -data-assign
18094@c Change the value of a program variable. Plenty of side effects.
18095@c @subsubheading GDB command
18096@c set variable
18097@c @subsubheading Example
18098@c N.A.
18099
18100@subheading The @code{-data-disassemble} Command
18101@findex -data-disassemble
18102
18103@subsubheading Synopsis
18104
18105@smallexample
18106 -data-disassemble
18107 [ -s @var{start-addr} -e @var{end-addr} ]
18108 | [ -f @var{filename} -l @var{linenum} [ -n @var{lines} ] ]
18109 -- @var{mode}
18110@end smallexample
18111
18112@noindent
18113Where:
18114
18115@table @samp
18116@item @var{start-addr}
18117is the beginning address (or @code{$pc})
18118@item @var{end-addr}
18119is the end address
18120@item @var{filename}
18121is the name of the file to disassemble
18122@item @var{linenum}
18123is the line number to disassemble around
18124@item @var{lines}
18125is the the number of disassembly lines to be produced. If it is -1,
18126the whole function will be disassembled, in case no @var{end-addr} is
18127specified. If @var{end-addr} is specified as a non-zero value, and
18128@var{lines} is lower than the number of disassembly lines between
18129@var{start-addr} and @var{end-addr}, only @var{lines} lines are
18130displayed; if @var{lines} is higher than the number of lines between
18131@var{start-addr} and @var{end-addr}, only the lines up to @var{end-addr}
18132are displayed.
18133@item @var{mode}
18134is either 0 (meaning only disassembly) or 1 (meaning mixed source and
18135disassembly).
18136@end table
18137
18138@subsubheading Result
18139
18140The output for each instruction is composed of four fields:
18141
18142@itemize @bullet
18143@item Address
18144@item Func-name
18145@item Offset
18146@item Instruction
18147@end itemize
18148
18149Note that whatever included in the instruction field, is not manipulated
18150directely by @sc{gdb/mi}, i.e. it is not possible to adjust its format.
18151
18152@subsubheading @value{GDBN} Command
18153
18154There's no direct mapping from this command to the CLI.
18155
18156@subsubheading Example
18157
18158Disassemble from the current value of @code{$pc} to @code{$pc + 20}:
18159
18160@smallexample
18161(@value{GDBP})
18162-data-disassemble -s $pc -e "$pc + 20" -- 0
18163^done,
18164asm_insns=[
18165@{address="0x000107c0",func-name="main",offset="4",
18166inst="mov 2, %o0"@},
18167@{address="0x000107c4",func-name="main",offset="8",
18168inst="sethi %hi(0x11800), %o2"@},
18169@{address="0x000107c8",func-name="main",offset="12",
18170inst="or %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"@},
18171@{address="0x000107cc",func-name="main",offset="16",
18172inst="sethi %hi(0x11800), %o2"@},
18173@{address="0x000107d0",func-name="main",offset="20",
18174inst="or %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"@}]
18175(@value{GDBP})
18176@end smallexample
18177
18178Disassemble the whole @code{main} function. Line 32 is part of
18179@code{main}.
18180
18181@smallexample
18182-data-disassemble -f basics.c -l 32 -- 0
18183^done,asm_insns=[
18184@{address="0x000107bc",func-name="main",offset="0",
18185inst="save %sp, -112, %sp"@},
18186@{address="0x000107c0",func-name="main",offset="4",
18187inst="mov 2, %o0"@},
18188@{address="0x000107c4",func-name="main",offset="8",
18189inst="sethi %hi(0x11800), %o2"@},
18190[@dots{}]
18191@{address="0x0001081c",func-name="main",offset="96",inst="ret "@},
18192@{address="0x00010820",func-name="main",offset="100",inst="restore "@}]
18193(@value{GDBP})
18194@end smallexample
18195
18196Disassemble 3 instructions from the start of @code{main}:
18197
18198@smallexample
18199(@value{GDBP})
18200-data-disassemble -f basics.c -l 32 -n 3 -- 0
18201^done,asm_insns=[
18202@{address="0x000107bc",func-name="main",offset="0",
18203inst="save %sp, -112, %sp"@},
18204@{address="0x000107c0",func-name="main",offset="4",
18205inst="mov 2, %o0"@},
18206@{address="0x000107c4",func-name="main",offset="8",
18207inst="sethi %hi(0x11800), %o2"@}]
18208(@value{GDBP})
18209@end smallexample
18210
18211Disassemble 3 instructions from the start of @code{main} in mixed mode:
18212
18213@smallexample
18214(@value{GDBP})
18215-data-disassemble -f basics.c -l 32 -n 3 -- 1
18216^done,asm_insns=[
18217src_and_asm_line=@{line="31",
18218file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \
18219 testsuite/gdb.mi/basics.c",line_asm_insn=[
18220@{address="0x000107bc",func-name="main",offset="0",
18221inst="save %sp, -112, %sp"@}]@},
18222src_and_asm_line=@{line="32",
18223file="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb/ \
18224 testsuite/gdb.mi/basics.c",line_asm_insn=[
18225@{address="0x000107c0",func-name="main",offset="4",
18226inst="mov 2, %o0"@},
18227@{address="0x000107c4",func-name="main",offset="8",
18228inst="sethi %hi(0x11800), %o2"@}]@}]
18229(@value{GDBP})
18230@end smallexample
18231
18232
18233@subheading The @code{-data-evaluate-expression} Command
18234@findex -data-evaluate-expression
18235
18236@subsubheading Synopsis
18237
18238@smallexample
18239 -data-evaluate-expression @var{expr}
18240@end smallexample
18241
18242Evaluate @var{expr} as an expression. The expression could contain an
18243inferior function call. The function call will execute synchronously.
18244If the expression contains spaces, it must be enclosed in double quotes.
18245
18246@subsubheading @value{GDBN} Command
18247
18248The corresponding @value{GDBN} commands are @samp{print}, @samp{output}, and
18249@samp{call}. In @code{gdbtk} only, there's a corresponding
18250@samp{gdb_eval} command.
18251
18252@subsubheading Example
18253
18254In the following example, the numbers that precede the commands are the
18255@dfn{tokens} described in @ref{GDB/MI Command Syntax, ,@sc{gdb/mi}
18256Command Syntax}. Notice how @sc{gdb/mi} returns the same tokens in its
18257output.
18258
18259@smallexample
18260211-data-evaluate-expression A
18261211^done,value="1"
18262(@value{GDBP})
18263311-data-evaluate-expression &A
18264311^done,value="0xefffeb7c"
18265(@value{GDBP})
18266411-data-evaluate-expression A+3
18267411^done,value="4"
18268(@value{GDBP})
18269511-data-evaluate-expression "A + 3"
18270511^done,value="4"
18271(@value{GDBP})
18272@end smallexample
18273
18274
18275@subheading The @code{-data-list-changed-registers} Command
18276@findex -data-list-changed-registers
18277
18278@subsubheading Synopsis
18279
18280@smallexample
18281 -data-list-changed-registers
18282@end smallexample
18283
18284Display a list of the registers that have changed.
18285
18286@subsubheading @value{GDBN} Command
18287
18288@value{GDBN} doesn't have a direct analog for this command; @code{gdbtk}
18289has the corresponding command @samp{gdb_changed_register_list}.
18290
18291@subsubheading Example
18292
18293On a PPC MBX board:
18294
18295@smallexample
18296(@value{GDBP})
18297-exec-continue
18298^running
18299
18300(@value{GDBP})
18301*stopped,reason="breakpoint-hit",bkptno="1",frame=@{func="main",
948d5102 18302args=[],file="try.c",fullname="/home/foo/bar/try.c",line="5"@}
922fbb7b
AC
18303(@value{GDBP})
18304-data-list-changed-registers
18305^done,changed-registers=["0","1","2","4","5","6","7","8","9",
18306"10","11","13","14","15","16","17","18","19","20","21","22","23",
18307"24","25","26","27","28","30","31","64","65","66","67","69"]
18308(@value{GDBP})
18309@end smallexample
18310
18311
18312@subheading The @code{-data-list-register-names} Command
18313@findex -data-list-register-names
18314
18315@subsubheading Synopsis
18316
18317@smallexample
18318 -data-list-register-names [ ( @var{regno} )+ ]
18319@end smallexample
18320
18321Show a list of register names for the current target. If no arguments
18322are given, it shows a list of the names of all the registers. If
18323integer numbers are given as arguments, it will print a list of the
18324names of the registers corresponding to the arguments. To ensure
18325consistency between a register name and its number, the output list may
18326include empty register names.
18327
18328@subsubheading @value{GDBN} Command
18329
18330@value{GDBN} does not have a command which corresponds to
18331@samp{-data-list-register-names}. In @code{gdbtk} there is a
18332corresponding command @samp{gdb_regnames}.
18333
18334@subsubheading Example
18335
18336For the PPC MBX board:
18337@smallexample
18338(@value{GDBP})
18339-data-list-register-names
18340^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7",
18341"r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18",
18342"r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29",
18343"r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9",
18344"f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20",
18345"f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31",
18346"", "pc","ps","cr","lr","ctr","xer"]
18347(@value{GDBP})
18348-data-list-register-names 1 2 3
18349^done,register-names=["r1","r2","r3"]
18350(@value{GDBP})
18351@end smallexample
18352
18353@subheading The @code{-data-list-register-values} Command
18354@findex -data-list-register-values
18355
18356@subsubheading Synopsis
18357
18358@smallexample
18359 -data-list-register-values @var{fmt} [ ( @var{regno} )*]
18360@end smallexample
18361
18362Display the registers' contents. @var{fmt} is the format according to
18363which the registers' contents are to be returned, followed by an optional
18364list of numbers specifying the registers to display. A missing list of
18365numbers indicates that the contents of all the registers must be returned.
18366
18367Allowed formats for @var{fmt} are:
18368
18369@table @code
18370@item x
18371Hexadecimal
18372@item o
18373Octal
18374@item t
18375Binary
18376@item d
18377Decimal
18378@item r
18379Raw
18380@item N
18381Natural
18382@end table
18383
18384@subsubheading @value{GDBN} Command
18385
18386The corresponding @value{GDBN} commands are @samp{info reg}, @samp{info
18387all-reg}, and (in @code{gdbtk}) @samp{gdb_fetch_registers}.
18388
18389@subsubheading Example
18390
18391For a PPC MBX board (note: line breaks are for readability only, they
18392don't appear in the actual output):
18393
18394@smallexample
18395(@value{GDBP})
18396-data-list-register-values r 64 65
18397^done,register-values=[@{number="64",value="0xfe00a300"@},
18398@{number="65",value="0x00029002"@}]
18399(@value{GDBP})
18400-data-list-register-values x
18401^done,register-values=[@{number="0",value="0xfe0043c8"@},
18402@{number="1",value="0x3fff88"@},@{number="2",value="0xfffffffe"@},
18403@{number="3",value="0x0"@},@{number="4",value="0xa"@},
18404@{number="5",value="0x3fff68"@},@{number="6",value="0x3fff58"@},
18405@{number="7",value="0xfe011e98"@},@{number="8",value="0x2"@},
18406@{number="9",value="0xfa202820"@},@{number="10",value="0xfa202808"@},
18407@{number="11",value="0x1"@},@{number="12",value="0x0"@},
18408@{number="13",value="0x4544"@},@{number="14",value="0xffdfffff"@},
18409@{number="15",value="0xffffffff"@},@{number="16",value="0xfffffeff"@},
18410@{number="17",value="0xefffffed"@},@{number="18",value="0xfffffffe"@},
18411@{number="19",value="0xffffffff"@},@{number="20",value="0xffffffff"@},
18412@{number="21",value="0xffffffff"@},@{number="22",value="0xfffffff7"@},
18413@{number="23",value="0xffffffff"@},@{number="24",value="0xffffffff"@},
18414@{number="25",value="0xffffffff"@},@{number="26",value="0xfffffffb"@},
18415@{number="27",value="0xffffffff"@},@{number="28",value="0xf7bfffff"@},
18416@{number="29",value="0x0"@},@{number="30",value="0xfe010000"@},
18417@{number="31",value="0x0"@},@{number="32",value="0x0"@},
18418@{number="33",value="0x0"@},@{number="34",value="0x0"@},
18419@{number="35",value="0x0"@},@{number="36",value="0x0"@},
18420@{number="37",value="0x0"@},@{number="38",value="0x0"@},
18421@{number="39",value="0x0"@},@{number="40",value="0x0"@},
18422@{number="41",value="0x0"@},@{number="42",value="0x0"@},
18423@{number="43",value="0x0"@},@{number="44",value="0x0"@},
18424@{number="45",value="0x0"@},@{number="46",value="0x0"@},
18425@{number="47",value="0x0"@},@{number="48",value="0x0"@},
18426@{number="49",value="0x0"@},@{number="50",value="0x0"@},
18427@{number="51",value="0x0"@},@{number="52",value="0x0"@},
18428@{number="53",value="0x0"@},@{number="54",value="0x0"@},
18429@{number="55",value="0x0"@},@{number="56",value="0x0"@},
18430@{number="57",value="0x0"@},@{number="58",value="0x0"@},
18431@{number="59",value="0x0"@},@{number="60",value="0x0"@},
18432@{number="61",value="0x0"@},@{number="62",value="0x0"@},
18433@{number="63",value="0x0"@},@{number="64",value="0xfe00a300"@},
18434@{number="65",value="0x29002"@},@{number="66",value="0x202f04b5"@},
18435@{number="67",value="0xfe0043b0"@},@{number="68",value="0xfe00b3e4"@},
18436@{number="69",value="0x20002b03"@}]
18437(@value{GDBP})
18438@end smallexample
18439
18440
18441@subheading The @code{-data-read-memory} Command
18442@findex -data-read-memory
18443
18444@subsubheading Synopsis
18445
18446@smallexample
18447 -data-read-memory [ -o @var{byte-offset} ]
18448 @var{address} @var{word-format} @var{word-size}
18449 @var{nr-rows} @var{nr-cols} [ @var{aschar} ]
18450@end smallexample
18451
18452@noindent
18453where:
18454
18455@table @samp
18456@item @var{address}
18457An expression specifying the address of the first memory word to be
18458read. Complex expressions containing embedded white space should be
18459quoted using the C convention.
18460
18461@item @var{word-format}
18462The format to be used to print the memory words. The notation is the
18463same as for @value{GDBN}'s @code{print} command (@pxref{Output Formats,
18464,Output formats}).
18465
18466@item @var{word-size}
18467The size of each memory word in bytes.
18468
18469@item @var{nr-rows}
18470The number of rows in the output table.
18471
18472@item @var{nr-cols}
18473The number of columns in the output table.
18474
18475@item @var{aschar}
18476If present, indicates that each row should include an @sc{ascii} dump. The
18477value of @var{aschar} is used as a padding character when a byte is not a
18478member of the printable @sc{ascii} character set (printable @sc{ascii}
18479characters are those whose code is between 32 and 126, inclusively).
18480
18481@item @var{byte-offset}
18482An offset to add to the @var{address} before fetching memory.
18483@end table
18484
18485This command displays memory contents as a table of @var{nr-rows} by
18486@var{nr-cols} words, each word being @var{word-size} bytes. In total,
18487@code{@var{nr-rows} * @var{nr-cols} * @var{word-size}} bytes are read
18488(returned as @samp{total-bytes}). Should less than the requested number
18489of bytes be returned by the target, the missing words are identified
18490using @samp{N/A}. The number of bytes read from the target is returned
18491in @samp{nr-bytes} and the starting address used to read memory in
18492@samp{addr}.
18493
18494The address of the next/previous row or page is available in
18495@samp{next-row} and @samp{prev-row}, @samp{next-page} and
18496@samp{prev-page}.
18497
18498@subsubheading @value{GDBN} Command
18499
18500The corresponding @value{GDBN} command is @samp{x}. @code{gdbtk} has
18501@samp{gdb_get_mem} memory read command.
18502
18503@subsubheading Example
18504
18505Read six bytes of memory starting at @code{bytes+6} but then offset by
18506@code{-6} bytes. Format as three rows of two columns. One byte per
18507word. Display each word in hex.
18508
18509@smallexample
18510(@value{GDBP})
185119-data-read-memory -o -6 -- bytes+6 x 1 3 2
185129^done,addr="0x00001390",nr-bytes="6",total-bytes="6",
18513next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396",
18514prev-page="0x0000138a",memory=[
18515@{addr="0x00001390",data=["0x00","0x01"]@},
18516@{addr="0x00001392",data=["0x02","0x03"]@},
18517@{addr="0x00001394",data=["0x04","0x05"]@}]
18518(@value{GDBP})
18519@end smallexample
18520
18521Read two bytes of memory starting at address @code{shorts + 64} and
18522display as a single word formatted in decimal.
18523
18524@smallexample
18525(@value{GDBP})
185265-data-read-memory shorts+64 d 2 1 1
185275^done,addr="0x00001510",nr-bytes="2",total-bytes="2",
18528next-row="0x00001512",prev-row="0x0000150e",
18529next-page="0x00001512",prev-page="0x0000150e",memory=[
18530@{addr="0x00001510",data=["128"]@}]
18531(@value{GDBP})
18532@end smallexample
18533
18534Read thirty two bytes of memory starting at @code{bytes+16} and format
18535as eight rows of four columns. Include a string encoding with @samp{x}
18536used as the non-printable character.
18537
18538@smallexample
18539(@value{GDBP})
185404-data-read-memory bytes+16 x 1 8 4 x
185414^done,addr="0x000013a0",nr-bytes="32",total-bytes="32",
18542next-row="0x000013c0",prev-row="0x0000139c",
18543next-page="0x000013c0",prev-page="0x00001380",memory=[
18544@{addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"@},
18545@{addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"@},
18546@{addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"@},
18547@{addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"@},
18548@{addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"@},
18549@{addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"@},
18550@{addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"@},
18551@{addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"@}]
18552(@value{GDBP})
18553@end smallexample
18554
18555@subheading The @code{-display-delete} Command
18556@findex -display-delete
18557
18558@subsubheading Synopsis
18559
18560@smallexample
18561 -display-delete @var{number}
18562@end smallexample
18563
18564Delete the display @var{number}.
18565
18566@subsubheading @value{GDBN} Command
18567
18568The corresponding @value{GDBN} command is @samp{delete display}.
18569
18570@subsubheading Example
18571N.A.
18572
18573
18574@subheading The @code{-display-disable} Command
18575@findex -display-disable
18576
18577@subsubheading Synopsis
18578
18579@smallexample
18580 -display-disable @var{number}
18581@end smallexample
18582
18583Disable display @var{number}.
18584
18585@subsubheading @value{GDBN} Command
18586
18587The corresponding @value{GDBN} command is @samp{disable display}.
18588
18589@subsubheading Example
18590N.A.
18591
18592
18593@subheading The @code{-display-enable} Command
18594@findex -display-enable
18595
18596@subsubheading Synopsis
18597
18598@smallexample
18599 -display-enable @var{number}
18600@end smallexample
18601
18602Enable display @var{number}.
18603
18604@subsubheading @value{GDBN} Command
18605
18606The corresponding @value{GDBN} command is @samp{enable display}.
18607
18608@subsubheading Example
18609N.A.
18610
18611
18612@subheading The @code{-display-insert} Command
18613@findex -display-insert
18614
18615@subsubheading Synopsis
18616
18617@smallexample
18618 -display-insert @var{expression}
18619@end smallexample
18620
18621Display @var{expression} every time the program stops.
18622
18623@subsubheading @value{GDBN} Command
18624
18625The corresponding @value{GDBN} command is @samp{display}.
18626
18627@subsubheading Example
18628N.A.
18629
18630
18631@subheading The @code{-display-list} Command
18632@findex -display-list
18633
18634@subsubheading Synopsis
18635
18636@smallexample
18637 -display-list
18638@end smallexample
18639
18640List the displays. Do not show the current values.
18641
18642@subsubheading @value{GDBN} Command
18643
18644The corresponding @value{GDBN} command is @samp{info display}.
18645
18646@subsubheading Example
18647N.A.
18648
18649
18650@subheading The @code{-environment-cd} Command
18651@findex -environment-cd
18652
18653@subsubheading Synopsis
18654
18655@smallexample
18656 -environment-cd @var{pathdir}
18657@end smallexample
18658
18659Set @value{GDBN}'s working directory.
18660
18661@subsubheading @value{GDBN} Command
18662
18663The corresponding @value{GDBN} command is @samp{cd}.
18664
18665@subsubheading Example
18666
18667@smallexample
18668(@value{GDBP})
18669-environment-cd /kwikemart/marge/ezannoni/flathead-dev/devo/gdb
18670^done
18671(@value{GDBP})
18672@end smallexample
18673
18674
18675@subheading The @code{-environment-directory} Command
18676@findex -environment-directory
18677
18678@subsubheading Synopsis
18679
18680@smallexample
18681 -environment-directory [ -r ] [ @var{pathdir} ]+
18682@end smallexample
18683
18684Add directories @var{pathdir} to beginning of search path for source files.
18685If the @samp{-r} option is used, the search path is reset to the default
b383017d 18686search path. If directories @var{pathdir} are supplied in addition to the
922fbb7b
AC
18687@samp{-r} option, the search path is first reset and then addition
18688occurs as normal.
b383017d 18689Multiple directories may be specified, separated by blanks. Specifying
922fbb7b
AC
18690multiple directories in a single command
18691results in the directories added to the beginning of the
18692search path in the same order they were presented in the command.
18693If blanks are needed as
18694part of a directory name, double-quotes should be used around
18695the name. In the command output, the path will show up separated
b383017d 18696by the system directory-separator character. The directory-seperator
922fbb7b
AC
18697character must not be used
18698in any directory name.
18699If no directories are specified, the current search path is displayed.
18700
18701@subsubheading @value{GDBN} Command
18702
18703The corresponding @value{GDBN} command is @samp{dir}.
18704
18705@subsubheading Example
18706
18707@smallexample
18708(@value{GDBP})
18709-environment-directory /kwikemart/marge/ezannoni/flathead-dev/devo/gdb
18710^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd"
18711(@value{GDBP})
18712-environment-directory ""
18713^done,source-path="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb:$cdir:$cwd"
18714(@value{GDBP})
18715-environment-directory -r /home/jjohnstn/src/gdb /usr/src
18716^done,source-path="/home/jjohnstn/src/gdb:/usr/src:$cdir:$cwd"
18717(@value{GDBP})
18718-environment-directory -r
18719^done,source-path="$cdir:$cwd"
18720(@value{GDBP})
18721@end smallexample
18722
18723
18724@subheading The @code{-environment-path} Command
18725@findex -environment-path
18726
18727@subsubheading Synopsis
18728
18729@smallexample
18730 -environment-path [ -r ] [ @var{pathdir} ]+
18731@end smallexample
18732
18733Add directories @var{pathdir} to beginning of search path for object files.
18734If the @samp{-r} option is used, the search path is reset to the original
b383017d
RM
18735search path that existed at gdb start-up. If directories @var{pathdir} are
18736supplied in addition to the
922fbb7b
AC
18737@samp{-r} option, the search path is first reset and then addition
18738occurs as normal.
b383017d 18739Multiple directories may be specified, separated by blanks. Specifying
922fbb7b
AC
18740multiple directories in a single command
18741results in the directories added to the beginning of the
18742search path in the same order they were presented in the command.
18743If blanks are needed as
18744part of a directory name, double-quotes should be used around
18745the name. In the command output, the path will show up separated
b383017d 18746by the system directory-separator character. The directory-seperator
922fbb7b
AC
18747character must not be used
18748in any directory name.
18749If no directories are specified, the current path is displayed.
18750
18751
18752@subsubheading @value{GDBN} Command
18753
18754The corresponding @value{GDBN} command is @samp{path}.
18755
18756@subsubheading Example
18757
18758@smallexample
18759(@value{GDBP})
b383017d 18760-environment-path
922fbb7b
AC
18761^done,path="/usr/bin"
18762(@value{GDBP})
18763-environment-path /kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb /bin
18764^done,path="/kwikemart/marge/ezannoni/flathead-dev/ppc-eabi/gdb:/bin:/usr/bin"
18765(@value{GDBP})
18766-environment-path -r /usr/local/bin
18767^done,path="/usr/local/bin:/usr/bin"
18768(@value{GDBP})
18769@end smallexample
18770
18771
18772@subheading The @code{-environment-pwd} Command
18773@findex -environment-pwd
18774
18775@subsubheading Synopsis
18776
18777@smallexample
18778 -environment-pwd
18779@end smallexample
18780
18781Show the current working directory.
18782
18783@subsubheading @value{GDBN} command
18784
18785The corresponding @value{GDBN} command is @samp{pwd}.
18786
18787@subsubheading Example
18788
18789@smallexample
18790(@value{GDBP})
18791-environment-pwd
18792^done,cwd="/kwikemart/marge/ezannoni/flathead-dev/devo/gdb"
18793(@value{GDBP})
18794@end smallexample
18795
18796@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
18797@node GDB/MI Program Control
18798@section @sc{gdb/mi} Program control
18799
18800@subsubheading Program termination
18801
18802As a result of execution, the inferior program can run to completion, if
18803it doesn't encounter any breakpoints. In this case the output will
18804include an exit code, if the program has exited exceptionally.
18805
18806@subsubheading Examples
18807
18808@noindent
18809Program exited normally:
18810
18811@smallexample
18812(@value{GDBP})
18813-exec-run
18814^running
18815(@value{GDBP})
18816x = 55
18817*stopped,reason="exited-normally"
18818(@value{GDBP})
18819@end smallexample
18820
18821@noindent
18822Program exited exceptionally:
18823
18824@smallexample
18825(@value{GDBP})
18826-exec-run
18827^running
18828(@value{GDBP})
18829x = 55
18830*stopped,reason="exited",exit-code="01"
18831(@value{GDBP})
18832@end smallexample
18833
18834Another way the program can terminate is if it receives a signal such as
18835@code{SIGINT}. In this case, @sc{gdb/mi} displays this:
18836
18837@smallexample
18838(@value{GDBP})
18839*stopped,reason="exited-signalled",signal-name="SIGINT",
18840signal-meaning="Interrupt"
18841@end smallexample
18842
18843
18844@subheading The @code{-exec-abort} Command
18845@findex -exec-abort
18846
18847@subsubheading Synopsis
18848
18849@smallexample
18850 -exec-abort
18851@end smallexample
18852
18853Kill the inferior running program.
18854
18855@subsubheading @value{GDBN} Command
18856
18857The corresponding @value{GDBN} command is @samp{kill}.
18858
18859@subsubheading Example
18860N.A.
18861
18862
18863@subheading The @code{-exec-arguments} Command
18864@findex -exec-arguments
18865
18866@subsubheading Synopsis
18867
18868@smallexample
18869 -exec-arguments @var{args}
18870@end smallexample
18871
18872Set the inferior program arguments, to be used in the next
18873@samp{-exec-run}.
18874
18875@subsubheading @value{GDBN} Command
18876
18877The corresponding @value{GDBN} command is @samp{set args}.
18878
18879@subsubheading Example
18880
18881@c FIXME!
18882Don't have one around.
18883
18884
18885@subheading The @code{-exec-continue} Command
18886@findex -exec-continue
18887
18888@subsubheading Synopsis
18889
18890@smallexample
18891 -exec-continue
18892@end smallexample
18893
18894Asynchronous command. Resumes the execution of the inferior program
18895until a breakpoint is encountered, or until the inferior exits.
18896
18897@subsubheading @value{GDBN} Command
18898
18899The corresponding @value{GDBN} corresponding is @samp{continue}.
18900
18901@subsubheading Example
18902
18903@smallexample
18904-exec-continue
18905^running
18906(@value{GDBP})
18907@@Hello world
18908*stopped,reason="breakpoint-hit",bkptno="2",frame=@{func="foo",args=[],
948d5102 18909file="hello.c",fullname="/home/foo/bar/hello.c",line="13"@}
922fbb7b
AC
18910(@value{GDBP})
18911@end smallexample
18912
18913
18914@subheading The @code{-exec-finish} Command
18915@findex -exec-finish
18916
18917@subsubheading Synopsis
18918
18919@smallexample
18920 -exec-finish
18921@end smallexample
18922
18923Asynchronous command. Resumes the execution of the inferior program
18924until the current function is exited. Displays the results returned by
18925the function.
18926
18927@subsubheading @value{GDBN} Command
18928
18929The corresponding @value{GDBN} command is @samp{finish}.
18930
18931@subsubheading Example
18932
18933Function returning @code{void}.
18934
18935@smallexample
18936-exec-finish
18937^running
18938(@value{GDBP})
18939@@hello from foo
18940*stopped,reason="function-finished",frame=@{func="main",args=[],
948d5102 18941file="hello.c",fullname="/home/foo/bar/hello.c",line="7"@}
922fbb7b
AC
18942(@value{GDBP})
18943@end smallexample
18944
18945Function returning other than @code{void}. The name of the internal
18946@value{GDBN} variable storing the result is printed, together with the
18947value itself.
18948
18949@smallexample
18950-exec-finish
18951^running
18952(@value{GDBP})
18953*stopped,reason="function-finished",frame=@{addr="0x000107b0",func="foo",
18954args=[@{name="a",value="1"],@{name="b",value="9"@}@},
948d5102 18955file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b
AC
18956gdb-result-var="$1",return-value="0"
18957(@value{GDBP})
18958@end smallexample
18959
18960
18961@subheading The @code{-exec-interrupt} Command
18962@findex -exec-interrupt
18963
18964@subsubheading Synopsis
18965
18966@smallexample
18967 -exec-interrupt
18968@end smallexample
18969
18970Asynchronous command. Interrupts the background execution of the target.
18971Note how the token associated with the stop message is the one for the
18972execution command that has been interrupted. The token for the interrupt
18973itself only appears in the @samp{^done} output. If the user is trying to
18974interrupt a non-running program, an error message will be printed.
18975
18976@subsubheading @value{GDBN} Command
18977
18978The corresponding @value{GDBN} command is @samp{interrupt}.
18979
18980@subsubheading Example
18981
18982@smallexample
18983(@value{GDBP})
18984111-exec-continue
18985111^running
18986
18987(@value{GDBP})
18988222-exec-interrupt
18989222^done
18990(@value{GDBP})
18991111*stopped,signal-name="SIGINT",signal-meaning="Interrupt",
76ff342d 18992frame=@{addr="0x00010140",func="foo",args=[],file="try.c",
948d5102 18993fullname="/home/foo/bar/try.c",line="13"@}
922fbb7b
AC
18994(@value{GDBP})
18995
18996(@value{GDBP})
18997-exec-interrupt
18998^error,msg="mi_cmd_exec_interrupt: Inferior not executing."
18999(@value{GDBP})
19000@end smallexample
19001
19002
19003@subheading The @code{-exec-next} Command
19004@findex -exec-next
19005
19006@subsubheading Synopsis
19007
19008@smallexample
19009 -exec-next
19010@end smallexample
19011
19012Asynchronous command. Resumes execution of the inferior program, stopping
19013when the beginning of the next source line is reached.
19014
19015@subsubheading @value{GDBN} Command
19016
19017The corresponding @value{GDBN} command is @samp{next}.
19018
19019@subsubheading Example
19020
19021@smallexample
19022-exec-next
19023^running
19024(@value{GDBP})
19025*stopped,reason="end-stepping-range",line="8",file="hello.c"
19026(@value{GDBP})
19027@end smallexample
19028
19029
19030@subheading The @code{-exec-next-instruction} Command
19031@findex -exec-next-instruction
19032
19033@subsubheading Synopsis
19034
19035@smallexample
19036 -exec-next-instruction
19037@end smallexample
19038
19039Asynchronous command. Executes one machine instruction. If the
19040instruction is a function call continues until the function returns. If
19041the program stops at an instruction in the middle of a source line, the
19042address will be printed as well.
19043
19044@subsubheading @value{GDBN} Command
19045
19046The corresponding @value{GDBN} command is @samp{nexti}.
19047
19048@subsubheading Example
19049
19050@smallexample
19051(@value{GDBP})
19052-exec-next-instruction
19053^running
19054
19055(@value{GDBP})
19056*stopped,reason="end-stepping-range",
19057addr="0x000100d4",line="5",file="hello.c"
19058(@value{GDBP})
19059@end smallexample
19060
19061
19062@subheading The @code{-exec-return} Command
19063@findex -exec-return
19064
19065@subsubheading Synopsis
19066
19067@smallexample
19068 -exec-return
19069@end smallexample
19070
19071Makes current function return immediately. Doesn't execute the inferior.
19072Displays the new current frame.
19073
19074@subsubheading @value{GDBN} Command
19075
19076The corresponding @value{GDBN} command is @samp{return}.
19077
19078@subsubheading Example
19079
19080@smallexample
19081(@value{GDBP})
19082200-break-insert callee4
19083200^done,bkpt=@{number="1",addr="0x00010734",
19084file="../../../devo/gdb/testsuite/gdb.mi/basics.c",line="8"@}
19085(@value{GDBP})
19086000-exec-run
19087000^running
19088(@value{GDBP})
19089000*stopped,reason="breakpoint-hit",bkptno="1",
19090frame=@{func="callee4",args=[],
76ff342d
DJ
19091file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19092fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@}
922fbb7b
AC
19093(@value{GDBP})
19094205-break-delete
19095205^done
19096(@value{GDBP})
19097111-exec-return
19098111^done,frame=@{level="0",func="callee3",
19099args=[@{name="strarg",
19100value="0x11940 \"A string argument.\""@}],
76ff342d
DJ
19101file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19102fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="18"@}
922fbb7b
AC
19103(@value{GDBP})
19104@end smallexample
19105
19106
19107@subheading The @code{-exec-run} Command
19108@findex -exec-run
19109
19110@subsubheading Synopsis
19111
19112@smallexample
19113 -exec-run
19114@end smallexample
19115
19116Asynchronous command. Starts execution of the inferior from the
19117beginning. The inferior executes until either a breakpoint is
19118encountered or the program exits.
19119
19120@subsubheading @value{GDBN} Command
19121
19122The corresponding @value{GDBN} command is @samp{run}.
19123
19124@subsubheading Example
19125
19126@smallexample
19127(@value{GDBP})
19128-break-insert main
19129^done,bkpt=@{number="1",addr="0x0001072c",file="recursive2.c",line="4"@}
19130(@value{GDBP})
19131-exec-run
19132^running
19133(@value{GDBP})
19134*stopped,reason="breakpoint-hit",bkptno="1",
76ff342d 19135frame=@{func="main",args=[],file="recursive2.c",
948d5102 19136fullname="/home/foo/bar/recursive2.c",line="4"@}
922fbb7b
AC
19137(@value{GDBP})
19138@end smallexample
19139
19140
19141@subheading The @code{-exec-show-arguments} Command
19142@findex -exec-show-arguments
19143
19144@subsubheading Synopsis
19145
19146@smallexample
19147 -exec-show-arguments
19148@end smallexample
19149
19150Print the arguments of the program.
19151
19152@subsubheading @value{GDBN} Command
19153
19154The corresponding @value{GDBN} command is @samp{show args}.
19155
19156@subsubheading Example
19157N.A.
19158
19159@c @subheading -exec-signal
19160
19161@subheading The @code{-exec-step} Command
19162@findex -exec-step
19163
19164@subsubheading Synopsis
19165
19166@smallexample
19167 -exec-step
19168@end smallexample
19169
19170Asynchronous command. Resumes execution of the inferior program, stopping
19171when the beginning of the next source line is reached, if the next
19172source line is not a function call. If it is, stop at the first
19173instruction of the called function.
19174
19175@subsubheading @value{GDBN} Command
19176
19177The corresponding @value{GDBN} command is @samp{step}.
19178
19179@subsubheading Example
19180
19181Stepping into a function:
19182
19183@smallexample
19184-exec-step
19185^running
19186(@value{GDBP})
19187*stopped,reason="end-stepping-range",
19188frame=@{func="foo",args=[@{name="a",value="10"@},
76ff342d 19189@{name="b",value="0"@}],file="recursive2.c",
948d5102 19190fullname="/home/foo/bar/recursive2.c",line="11"@}
922fbb7b
AC
19191(@value{GDBP})
19192@end smallexample
19193
19194Regular stepping:
19195
19196@smallexample
19197-exec-step
19198^running
19199(@value{GDBP})
19200*stopped,reason="end-stepping-range",line="14",file="recursive2.c"
19201(@value{GDBP})
19202@end smallexample
19203
19204
19205@subheading The @code{-exec-step-instruction} Command
19206@findex -exec-step-instruction
19207
19208@subsubheading Synopsis
19209
19210@smallexample
19211 -exec-step-instruction
19212@end smallexample
19213
19214Asynchronous command. Resumes the inferior which executes one machine
19215instruction. The output, once @value{GDBN} has stopped, will vary depending on
19216whether we have stopped in the middle of a source line or not. In the
19217former case, the address at which the program stopped will be printed as
19218well.
19219
19220@subsubheading @value{GDBN} Command
19221
19222The corresponding @value{GDBN} command is @samp{stepi}.
19223
19224@subsubheading Example
19225
19226@smallexample
19227(@value{GDBP})
19228-exec-step-instruction
19229^running
19230
19231(@value{GDBP})
19232*stopped,reason="end-stepping-range",
76ff342d 19233frame=@{func="foo",args=[],file="try.c",
948d5102 19234fullname="/home/foo/bar/try.c",line="10"@}
922fbb7b
AC
19235(@value{GDBP})
19236-exec-step-instruction
19237^running
19238
19239(@value{GDBP})
19240*stopped,reason="end-stepping-range",
76ff342d 19241frame=@{addr="0x000100f4",func="foo",args=[],file="try.c",
948d5102 19242fullname="/home/foo/bar/try.c",line="10"@}
922fbb7b
AC
19243(@value{GDBP})
19244@end smallexample
19245
19246
19247@subheading The @code{-exec-until} Command
19248@findex -exec-until
19249
19250@subsubheading Synopsis
19251
19252@smallexample
19253 -exec-until [ @var{location} ]
19254@end smallexample
19255
19256Asynchronous command. Executes the inferior until the @var{location}
19257specified in the argument is reached. If there is no argument, the inferior
19258executes until a source line greater than the current one is reached.
19259The reason for stopping in this case will be @samp{location-reached}.
19260
19261@subsubheading @value{GDBN} Command
19262
19263The corresponding @value{GDBN} command is @samp{until}.
19264
19265@subsubheading Example
19266
19267@smallexample
19268(@value{GDBP})
19269-exec-until recursive2.c:6
19270^running
19271(@value{GDBP})
19272x = 55
19273*stopped,reason="location-reached",frame=@{func="main",args=[],
948d5102 19274file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="6"@}
922fbb7b
AC
19275(@value{GDBP})
19276@end smallexample
19277
19278@ignore
19279@subheading -file-clear
19280Is this going away????
19281@end ignore
19282
19283
19284@subheading The @code{-file-exec-and-symbols} Command
19285@findex -file-exec-and-symbols
19286
19287@subsubheading Synopsis
19288
19289@smallexample
19290 -file-exec-and-symbols @var{file}
19291@end smallexample
19292
19293Specify the executable file to be debugged. This file is the one from
19294which the symbol table is also read. If no file is specified, the
19295command clears the executable and symbol information. If breakpoints
19296are set when using this command with no arguments, @value{GDBN} will produce
19297error messages. Otherwise, no output is produced, except a completion
19298notification.
19299
19300@subsubheading @value{GDBN} Command
19301
19302The corresponding @value{GDBN} command is @samp{file}.
19303
19304@subsubheading Example
19305
19306@smallexample
19307(@value{GDBP})
19308-file-exec-and-symbols /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
19309^done
19310(@value{GDBP})
19311@end smallexample
19312
19313
19314@subheading The @code{-file-exec-file} Command
19315@findex -file-exec-file
19316
19317@subsubheading Synopsis
19318
19319@smallexample
19320 -file-exec-file @var{file}
19321@end smallexample
19322
19323Specify the executable file to be debugged. Unlike
19324@samp{-file-exec-and-symbols}, the symbol table is @emph{not} read
19325from this file. If used without argument, @value{GDBN} clears the information
19326about the executable file. No output is produced, except a completion
19327notification.
19328
19329@subsubheading @value{GDBN} Command
19330
19331The corresponding @value{GDBN} command is @samp{exec-file}.
19332
19333@subsubheading Example
19334
19335@smallexample
19336(@value{GDBP})
19337-file-exec-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
19338^done
19339(@value{GDBP})
19340@end smallexample
19341
19342
19343@subheading The @code{-file-list-exec-sections} Command
19344@findex -file-list-exec-sections
19345
19346@subsubheading Synopsis
19347
19348@smallexample
19349 -file-list-exec-sections
19350@end smallexample
19351
19352List the sections of the current executable file.
19353
19354@subsubheading @value{GDBN} Command
19355
19356The @value{GDBN} command @samp{info file} shows, among the rest, the same
19357information as this command. @code{gdbtk} has a corresponding command
19358@samp{gdb_load_info}.
19359
19360@subsubheading Example
19361N.A.
19362
19363
1abaf70c
BR
19364@subheading The @code{-file-list-exec-source-file} Command
19365@findex -file-list-exec-source-file
19366
19367@subsubheading Synopsis
19368
19369@smallexample
19370 -file-list-exec-source-file
19371@end smallexample
19372
b383017d 19373List the line number, the current source file, and the absolute path
1abaf70c
BR
19374to the current source file for the current executable.
19375
19376@subsubheading @value{GDBN} Command
19377
19378There's no @value{GDBN} command which directly corresponds to this one.
19379
19380@subsubheading Example
19381
19382@smallexample
19383(@value{GDBP})
19384123-file-list-exec-source-file
19385123^done,line="1",file="foo.c",fullname="/home/bar/foo.c"
19386(@value{GDBP})
19387@end smallexample
19388
19389
922fbb7b
AC
19390@subheading The @code{-file-list-exec-source-files} Command
19391@findex -file-list-exec-source-files
19392
19393@subsubheading Synopsis
19394
19395@smallexample
19396 -file-list-exec-source-files
19397@end smallexample
19398
19399List the source files for the current executable.
19400
57c22c6c
BR
19401It will always output the filename, but only when GDB can find the absolute
19402file name of a source file, will it output the fullname.
19403
922fbb7b
AC
19404@subsubheading @value{GDBN} Command
19405
19406There's no @value{GDBN} command which directly corresponds to this one.
19407@code{gdbtk} has an analogous command @samp{gdb_listfiles}.
19408
19409@subsubheading Example
57c22c6c
BR
19410@smallexample
19411(@value{GDBP})
19412-file-list-exec-source-files
19413^done,files=[
19414@{file=foo.c,fullname=/home/foo.c@},
19415@{file=/home/bar.c,fullname=/home/bar.c@},
19416@{file=gdb_could_not_find_fullpath.c@}]
19417(@value{GDBP})
19418@end smallexample
922fbb7b
AC
19419
19420@subheading The @code{-file-list-shared-libraries} Command
19421@findex -file-list-shared-libraries
19422
19423@subsubheading Synopsis
19424
19425@smallexample
19426 -file-list-shared-libraries
19427@end smallexample
19428
19429List the shared libraries in the program.
19430
19431@subsubheading @value{GDBN} Command
19432
19433The corresponding @value{GDBN} command is @samp{info shared}.
19434
19435@subsubheading Example
19436N.A.
19437
19438
19439@subheading The @code{-file-list-symbol-files} Command
19440@findex -file-list-symbol-files
19441
19442@subsubheading Synopsis
19443
19444@smallexample
19445 -file-list-symbol-files
19446@end smallexample
19447
19448List symbol files.
19449
19450@subsubheading @value{GDBN} Command
19451
19452The corresponding @value{GDBN} command is @samp{info file} (part of it).
19453
19454@subsubheading Example
19455N.A.
19456
19457
19458@subheading The @code{-file-symbol-file} Command
19459@findex -file-symbol-file
19460
19461@subsubheading Synopsis
19462
19463@smallexample
19464 -file-symbol-file @var{file}
19465@end smallexample
19466
19467Read symbol table info from the specified @var{file} argument. When
19468used without arguments, clears @value{GDBN}'s symbol table info. No output is
19469produced, except for a completion notification.
19470
19471@subsubheading @value{GDBN} Command
19472
19473The corresponding @value{GDBN} command is @samp{symbol-file}.
19474
19475@subsubheading Example
19476
19477@smallexample
19478(@value{GDBP})
19479-file-symbol-file /kwikemart/marge/ezannoni/TRUNK/mbx/hello.mbx
19480^done
19481(@value{GDBP})
19482@end smallexample
19483
19484@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19485@node GDB/MI Miscellaneous Commands
19486@section Miscellaneous @value{GDBN} commands in @sc{gdb/mi}
19487
19488@c @subheading -gdb-complete
19489
19490@subheading The @code{-gdb-exit} Command
19491@findex -gdb-exit
19492
19493@subsubheading Synopsis
19494
19495@smallexample
19496 -gdb-exit
19497@end smallexample
19498
19499Exit @value{GDBN} immediately.
19500
19501@subsubheading @value{GDBN} Command
19502
19503Approximately corresponds to @samp{quit}.
19504
19505@subsubheading Example
19506
19507@smallexample
19508(@value{GDBP})
19509-gdb-exit
19510@end smallexample
19511
19512@subheading The @code{-gdb-set} Command
19513@findex -gdb-set
19514
19515@subsubheading Synopsis
19516
19517@smallexample
19518 -gdb-set
19519@end smallexample
19520
19521Set an internal @value{GDBN} variable.
19522@c IS THIS A DOLLAR VARIABLE? OR SOMETHING LIKE ANNOTATE ?????
19523
19524@subsubheading @value{GDBN} Command
19525
19526The corresponding @value{GDBN} command is @samp{set}.
19527
19528@subsubheading Example
19529
19530@smallexample
19531(@value{GDBP})
19532-gdb-set $foo=3
19533^done
19534(@value{GDBP})
19535@end smallexample
19536
19537
19538@subheading The @code{-gdb-show} Command
19539@findex -gdb-show
19540
19541@subsubheading Synopsis
19542
19543@smallexample
19544 -gdb-show
19545@end smallexample
19546
19547Show the current value of a @value{GDBN} variable.
19548
19549@subsubheading @value{GDBN} command
19550
19551The corresponding @value{GDBN} command is @samp{show}.
19552
19553@subsubheading Example
19554
19555@smallexample
19556(@value{GDBP})
19557-gdb-show annotate
19558^done,value="0"
19559(@value{GDBP})
19560@end smallexample
19561
19562@c @subheading -gdb-source
19563
19564
19565@subheading The @code{-gdb-version} Command
19566@findex -gdb-version
19567
19568@subsubheading Synopsis
19569
19570@smallexample
19571 -gdb-version
19572@end smallexample
19573
19574Show version information for @value{GDBN}. Used mostly in testing.
19575
19576@subsubheading @value{GDBN} Command
19577
19578There's no equivalent @value{GDBN} command. @value{GDBN} by default shows this
19579information when you start an interactive session.
19580
19581@subsubheading Example
19582
19583@c This example modifies the actual output from GDB to avoid overfull
19584@c box in TeX.
19585@smallexample
19586(@value{GDBP})
19587-gdb-version
19588~GNU gdb 5.2.1
19589~Copyright 2000 Free Software Foundation, Inc.
19590~GDB is free software, covered by the GNU General Public License, and
19591~you are welcome to change it and/or distribute copies of it under
19592~ certain conditions.
19593~Type "show copying" to see the conditions.
19594~There is absolutely no warranty for GDB. Type "show warranty" for
19595~ details.
b383017d 19596~This GDB was configured as
922fbb7b
AC
19597 "--host=sparc-sun-solaris2.5.1 --target=ppc-eabi".
19598^done
19599(@value{GDBP})
19600@end smallexample
19601
19602@subheading The @code{-interpreter-exec} Command
19603@findex -interpreter-exec
19604
19605@subheading Synopsis
19606
19607@smallexample
19608-interpreter-exec @var{interpreter} @var{command}
19609@end smallexample
19610
19611Execute the specified @var{command} in the given @var{interpreter}.
19612
19613@subheading @value{GDBN} Command
19614
19615The corresponding @value{GDBN} command is @samp{interpreter-exec}.
19616
19617@subheading Example
19618
19619@smallexample
19620(@value{GDBP})
19621-interpreter-exec console "break main"
19622&"During symbol reading, couldn't parse type; debugger out of date?.\n"
19623&"During symbol reading, bad structure-type format.\n"
19624~"Breakpoint 1 at 0x8074fc6: file ../../src/gdb/main.c, line 743.\n"
19625^done
19626(@value{GDBP})
19627@end smallexample
19628
3cb3b8df
BR
19629@subheading The @code{-inferior-tty-set} Command
19630@findex -inferior-tty-set
19631
19632@subheading Synopsis
19633
19634@smallexample
19635-inferior-tty-set /dev/pts/1
19636@end smallexample
19637
19638Set terminal for future runs of the program being debugged.
19639
19640@subheading @value{GDBN} Command
19641
19642The corresponding @value{GDBN} command is @samp{set inferior-tty /dev/pts/1}.
19643
19644@subheading Example
19645
19646@smallexample
19647(@value{GDBP})
19648-inferior-tty-set /dev/pts/1
19649^done
19650(@value{GDBP})
19651@end smallexample
19652
19653@subheading The @code{-inferior-tty-show} Command
19654@findex -inferior-tty-show
19655
19656@subheading Synopsis
19657
19658@smallexample
19659-inferior-tty-show
19660@end smallexample
19661
19662Show terminal for future runs of program being debugged.
19663
19664@subheading @value{GDBN} Command
19665
38f1196a 19666The corresponding @value{GDBN} command is @samp{show inferior-tty}.
3cb3b8df
BR
19667
19668@subheading Example
19669
19670@smallexample
19671(@value{GDBP})
19672-inferior-tty-set /dev/pts/1
19673^done
19674(@value{GDBP})
19675-inferior-tty-show
19676^done,inferior_tty_terminal="/dev/pts/1"
19677(@value{GDBP})
19678@end smallexample
19679
922fbb7b
AC
19680@ignore
19681@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19682@node GDB/MI Kod Commands
19683@section @sc{gdb/mi} Kod Commands
19684
19685The Kod commands are not implemented.
19686
19687@c @subheading -kod-info
19688
19689@c @subheading -kod-list
19690
19691@c @subheading -kod-list-object-types
19692
19693@c @subheading -kod-show
19694
19695@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19696@node GDB/MI Memory Overlay Commands
19697@section @sc{gdb/mi} Memory Overlay Commands
19698
19699The memory overlay commands are not implemented.
19700
19701@c @subheading -overlay-auto
19702
19703@c @subheading -overlay-list-mapping-state
19704
19705@c @subheading -overlay-list-overlays
19706
19707@c @subheading -overlay-map
19708
19709@c @subheading -overlay-off
19710
19711@c @subheading -overlay-on
19712
19713@c @subheading -overlay-unmap
19714
19715@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19716@node GDB/MI Signal Handling Commands
19717@section @sc{gdb/mi} Signal Handling Commands
19718
19719Signal handling commands are not implemented.
19720
19721@c @subheading -signal-handle
19722
19723@c @subheading -signal-list-handle-actions
19724
19725@c @subheading -signal-list-signal-types
19726@end ignore
19727
19728
19729@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
19730@node GDB/MI Stack Manipulation
19731@section @sc{gdb/mi} Stack Manipulation Commands
19732
dcaaae04
NR
19733
19734@subheading The @code{-stack-info-frame} Command
19735@findex -stack-info-frame
19736
19737@subsubheading Synopsis
19738
19739@smallexample
19740 -stack-info-frame
19741@end smallexample
19742
19743Get info on the selected frame.
19744
19745@subsubheading @value{GDBN} Command
19746
19747The corresponding @value{GDBN} command is @samp{info frame} or @samp{frame}
19748(without arguments).
19749
19750@subsubheading Example
19751
19752@smallexample
19753(@value{GDBP})
19754-stack-info-frame
19755^done,frame=@{level="1",addr="0x0001076c",func="callee3",
19756file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19757fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@}
19758(@value{GDBP})
19759@end smallexample
19760
922fbb7b
AC
19761@subheading The @code{-stack-info-depth} Command
19762@findex -stack-info-depth
19763
19764@subsubheading Synopsis
19765
19766@smallexample
19767 -stack-info-depth [ @var{max-depth} ]
19768@end smallexample
19769
19770Return the depth of the stack. If the integer argument @var{max-depth}
19771is specified, do not count beyond @var{max-depth} frames.
19772
19773@subsubheading @value{GDBN} Command
19774
19775There's no equivalent @value{GDBN} command.
19776
19777@subsubheading Example
19778
19779For a stack with frame levels 0 through 11:
19780
19781@smallexample
19782(@value{GDBP})
19783-stack-info-depth
19784^done,depth="12"
19785(@value{GDBP})
19786-stack-info-depth 4
19787^done,depth="4"
19788(@value{GDBP})
19789-stack-info-depth 12
19790^done,depth="12"
19791(@value{GDBP})
19792-stack-info-depth 11
19793^done,depth="11"
19794(@value{GDBP})
19795-stack-info-depth 13
19796^done,depth="12"
19797(@value{GDBP})
19798@end smallexample
19799
19800@subheading The @code{-stack-list-arguments} Command
19801@findex -stack-list-arguments
19802
19803@subsubheading Synopsis
19804
19805@smallexample
19806 -stack-list-arguments @var{show-values}
19807 [ @var{low-frame} @var{high-frame} ]
19808@end smallexample
19809
19810Display a list of the arguments for the frames between @var{low-frame}
19811and @var{high-frame} (inclusive). If @var{low-frame} and
19812@var{high-frame} are not provided, list the arguments for the whole call
19813stack.
19814
19815The @var{show-values} argument must have a value of 0 or 1. A value of
198160 means that only the names of the arguments are listed, a value of 1
19817means that both names and values of the arguments are printed.
19818
19819@subsubheading @value{GDBN} Command
19820
19821@value{GDBN} does not have an equivalent command. @code{gdbtk} has a
19822@samp{gdb_get_args} command which partially overlaps with the
19823functionality of @samp{-stack-list-arguments}.
19824
19825@subsubheading Example
19826
19827@smallexample
19828(@value{GDBP})
19829-stack-list-frames
19830^done,
19831stack=[
19832frame=@{level="0",addr="0x00010734",func="callee4",
76ff342d
DJ
19833file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19834fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="8"@},
922fbb7b 19835frame=@{level="1",addr="0x0001076c",func="callee3",
76ff342d
DJ
19836file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19837fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="17"@},
922fbb7b 19838frame=@{level="2",addr="0x0001078c",func="callee2",
76ff342d
DJ
19839file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19840fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="22"@},
922fbb7b 19841frame=@{level="3",addr="0x000107b4",func="callee1",
76ff342d
DJ
19842file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19843fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="27"@},
922fbb7b 19844frame=@{level="4",addr="0x000107e0",func="main",
76ff342d
DJ
19845file="../../../devo/gdb/testsuite/gdb.mi/basics.c",
19846fullname="/home/foo/bar/devo/gdb/testsuite/gdb.mi/basics.c",line="32"@}]
922fbb7b
AC
19847(@value{GDBP})
19848-stack-list-arguments 0
19849^done,
19850stack-args=[
19851frame=@{level="0",args=[]@},
19852frame=@{level="1",args=[name="strarg"]@},
19853frame=@{level="2",args=[name="intarg",name="strarg"]@},
19854frame=@{level="3",args=[name="intarg",name="strarg",name="fltarg"]@},
19855frame=@{level="4",args=[]@}]
19856(@value{GDBP})
19857-stack-list-arguments 1
19858^done,
19859stack-args=[
19860frame=@{level="0",args=[]@},
19861frame=@{level="1",
19862 args=[@{name="strarg",value="0x11940 \"A string argument.\""@}]@},
19863frame=@{level="2",args=[
19864@{name="intarg",value="2"@},
19865@{name="strarg",value="0x11940 \"A string argument.\""@}]@},
19866@{frame=@{level="3",args=[
19867@{name="intarg",value="2"@},
19868@{name="strarg",value="0x11940 \"A string argument.\""@},
19869@{name="fltarg",value="3.5"@}]@},
19870frame=@{level="4",args=[]@}]
19871(@value{GDBP})
19872-stack-list-arguments 0 2 2
19873^done,stack-args=[frame=@{level="2",args=[name="intarg",name="strarg"]@}]
19874(@value{GDBP})
19875-stack-list-arguments 1 2 2
19876^done,stack-args=[frame=@{level="2",
19877args=[@{name="intarg",value="2"@},
19878@{name="strarg",value="0x11940 \"A string argument.\""@}]@}]
19879(@value{GDBP})
19880@end smallexample
19881
19882@c @subheading -stack-list-exception-handlers
19883
19884
19885@subheading The @code{-stack-list-frames} Command
19886@findex -stack-list-frames
19887
19888@subsubheading Synopsis
19889
19890@smallexample
19891 -stack-list-frames [ @var{low-frame} @var{high-frame} ]
19892@end smallexample
19893
19894List the frames currently on the stack. For each frame it displays the
19895following info:
19896
19897@table @samp
19898@item @var{level}
19899The frame number, 0 being the topmost frame, i.e. the innermost function.
19900@item @var{addr}
19901The @code{$pc} value for that frame.
19902@item @var{func}
19903Function name.
19904@item @var{file}
19905File name of the source file where the function lives.
19906@item @var{line}
19907Line number corresponding to the @code{$pc}.
19908@end table
19909
19910If invoked without arguments, this command prints a backtrace for the
19911whole stack. If given two integer arguments, it shows the frames whose
19912levels are between the two arguments (inclusive). If the two arguments
19913are equal, it shows the single frame at the corresponding level.
19914
19915@subsubheading @value{GDBN} Command
19916
19917The corresponding @value{GDBN} commands are @samp{backtrace} and @samp{where}.
19918
19919@subsubheading Example
19920
19921Full stack backtrace:
19922
19923@smallexample
19924(@value{GDBP})
19925-stack-list-frames
19926^done,stack=
19927[frame=@{level="0",addr="0x0001076c",func="foo",
948d5102 19928 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="11"@},
922fbb7b 19929frame=@{level="1",addr="0x000107a4",func="foo",
948d5102 19930 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19931frame=@{level="2",addr="0x000107a4",func="foo",
948d5102 19932 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19933frame=@{level="3",addr="0x000107a4",func="foo",
948d5102 19934 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19935frame=@{level="4",addr="0x000107a4",func="foo",
948d5102 19936 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19937frame=@{level="5",addr="0x000107a4",func="foo",
948d5102 19938 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19939frame=@{level="6",addr="0x000107a4",func="foo",
948d5102 19940 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19941frame=@{level="7",addr="0x000107a4",func="foo",
948d5102 19942 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19943frame=@{level="8",addr="0x000107a4",func="foo",
948d5102 19944 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19945frame=@{level="9",addr="0x000107a4",func="foo",
948d5102 19946 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19947frame=@{level="10",addr="0x000107a4",func="foo",
948d5102 19948 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19949frame=@{level="11",addr="0x00010738",func="main",
948d5102 19950 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="4"@}]
922fbb7b
AC
19951(@value{GDBP})
19952@end smallexample
19953
19954Show frames between @var{low_frame} and @var{high_frame}:
19955
19956@smallexample
19957(@value{GDBP})
19958-stack-list-frames 3 5
19959^done,stack=
19960[frame=@{level="3",addr="0x000107a4",func="foo",
948d5102 19961 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19962frame=@{level="4",addr="0x000107a4",func="foo",
948d5102 19963 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@},
922fbb7b 19964frame=@{level="5",addr="0x000107a4",func="foo",
948d5102 19965 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}]
922fbb7b
AC
19966(@value{GDBP})
19967@end smallexample
19968
19969Show a single frame:
19970
19971@smallexample
19972(@value{GDBP})
19973-stack-list-frames 3 3
19974^done,stack=
19975[frame=@{level="3",addr="0x000107a4",func="foo",
948d5102 19976 file="recursive2.c",fullname="/home/foo/bar/recursive2.c",line="14"@}]
922fbb7b
AC
19977(@value{GDBP})
19978@end smallexample
19979
19980
19981@subheading The @code{-stack-list-locals} Command
19982@findex -stack-list-locals
19983
19984@subsubheading Synopsis
19985
19986@smallexample
19987 -stack-list-locals @var{print-values}
19988@end smallexample
19989
265eeb58
NR
19990Display the local variable names for the selected frame. If
19991@var{print-values} is 0 or @code{--no-values}, print only the names of
19992the variables; if it is 1 or @code{--all-values}, print also their
19993values; and if it is 2 or @code{--simple-values}, print the name,
19994type and value for simple data types and the name and type for arrays,
19995structures and unions. In this last case, a frontend can immediately
19996display the value of simple data types and create variable objects for
19997other data types when the the user wishes to explore their values in
bc8ced35 19998more detail.
922fbb7b
AC
19999
20000@subsubheading @value{GDBN} Command
20001
20002@samp{info locals} in @value{GDBN}, @samp{gdb_get_locals} in @code{gdbtk}.
20003
20004@subsubheading Example
20005
20006@smallexample
20007(@value{GDBP})
20008-stack-list-locals 0
20009^done,locals=[name="A",name="B",name="C"]
20010(@value{GDBP})
bc8ced35 20011-stack-list-locals --all-values
922fbb7b 20012^done,locals=[@{name="A",value="1"@},@{name="B",value="2"@},
bc8ced35
NR
20013 @{name="C",value="@{1, 2, 3@}"@}]
20014-stack-list-locals --simple-values
20015^done,locals=[@{name="A",type="int",value="1"@},
20016 @{name="B",type="int",value="2"@},@{name="C",type="int [3]"@}]
922fbb7b
AC
20017(@value{GDBP})
20018@end smallexample
20019
20020
20021@subheading The @code{-stack-select-frame} Command
20022@findex -stack-select-frame
20023
20024@subsubheading Synopsis
20025
20026@smallexample
20027 -stack-select-frame @var{framenum}
20028@end smallexample
20029
265eeb58 20030Change the selected frame. Select a different frame @var{framenum} on
922fbb7b
AC
20031the stack.
20032
20033@subsubheading @value{GDBN} Command
20034
20035The corresponding @value{GDBN} commands are @samp{frame}, @samp{up},
20036@samp{down}, @samp{select-frame}, @samp{up-silent}, and @samp{down-silent}.
20037
20038@subsubheading Example
20039
20040@smallexample
20041(@value{GDBP})
20042-stack-select-frame 2
20043^done
20044(@value{GDBP})
20045@end smallexample
20046
20047@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
20048@node GDB/MI Symbol Query
20049@section @sc{gdb/mi} Symbol Query Commands
20050
20051
20052@subheading The @code{-symbol-info-address} Command
20053@findex -symbol-info-address
20054
20055@subsubheading Synopsis
20056
20057@smallexample
20058 -symbol-info-address @var{symbol}
20059@end smallexample
20060
20061Describe where @var{symbol} is stored.
20062
20063@subsubheading @value{GDBN} Command
20064
20065The corresponding @value{GDBN} command is @samp{info address}.
20066
20067@subsubheading Example
20068N.A.
20069
20070
20071@subheading The @code{-symbol-info-file} Command
20072@findex -symbol-info-file
20073
20074@subsubheading Synopsis
20075
20076@smallexample
20077 -symbol-info-file
20078@end smallexample
20079
20080Show the file for the symbol.
20081
20082@subsubheading @value{GDBN} Command
20083
20084There's no equivalent @value{GDBN} command. @code{gdbtk} has
20085@samp{gdb_find_file}.
20086
20087@subsubheading Example
20088N.A.
20089
20090
20091@subheading The @code{-symbol-info-function} Command
20092@findex -symbol-info-function
20093
20094@subsubheading Synopsis
20095
20096@smallexample
20097 -symbol-info-function
20098@end smallexample
20099
20100Show which function the symbol lives in.
20101
20102@subsubheading @value{GDBN} Command
20103
20104@samp{gdb_get_function} in @code{gdbtk}.
20105
20106@subsubheading Example
20107N.A.
20108
20109
20110@subheading The @code{-symbol-info-line} Command
20111@findex -symbol-info-line
20112
20113@subsubheading Synopsis
20114
20115@smallexample
20116 -symbol-info-line
20117@end smallexample
20118
20119Show the core addresses of the code for a source line.
20120
20121@subsubheading @value{GDBN} Command
20122
71952f4c 20123The corresponding @value{GDBN} command is @samp{info line}.
922fbb7b
AC
20124@code{gdbtk} has the @samp{gdb_get_line} and @samp{gdb_get_file} commands.
20125
20126@subsubheading Example
20127N.A.
20128
20129
20130@subheading The @code{-symbol-info-symbol} Command
20131@findex -symbol-info-symbol
20132
20133@subsubheading Synopsis
20134
20135@smallexample
20136 -symbol-info-symbol @var{addr}
20137@end smallexample
20138
20139Describe what symbol is at location @var{addr}.
20140
20141@subsubheading @value{GDBN} Command
20142
20143The corresponding @value{GDBN} command is @samp{info symbol}.
20144
20145@subsubheading Example
20146N.A.
20147
20148
20149@subheading The @code{-symbol-list-functions} Command
20150@findex -symbol-list-functions
20151
20152@subsubheading Synopsis
20153
20154@smallexample
20155 -symbol-list-functions
20156@end smallexample
20157
20158List the functions in the executable.
20159
20160@subsubheading @value{GDBN} Command
20161
20162@samp{info functions} in @value{GDBN}, @samp{gdb_listfunc} and
20163@samp{gdb_search} in @code{gdbtk}.
20164
20165@subsubheading Example
20166N.A.
20167
20168
32e7087d
JB
20169@subheading The @code{-symbol-list-lines} Command
20170@findex -symbol-list-lines
20171
20172@subsubheading Synopsis
20173
20174@smallexample
20175 -symbol-list-lines @var{filename}
20176@end smallexample
20177
20178Print the list of lines that contain code and their associated program
20179addresses for the given source filename. The entries are sorted in
20180ascending PC order.
20181
20182@subsubheading @value{GDBN} Command
20183
20184There is no corresponding @value{GDBN} command.
20185
20186@subsubheading Example
20187@smallexample
20188(@value{GDBP})
20189-symbol-list-lines basics.c
54ff5908 20190^done,lines=[@{pc="0x08048554",line="7"@},@{pc="0x0804855a",line="8"@}]
32e7087d
JB
20191(@value{GDBP})
20192@end smallexample
20193
20194
922fbb7b
AC
20195@subheading The @code{-symbol-list-types} Command
20196@findex -symbol-list-types
20197
20198@subsubheading Synopsis
20199
20200@smallexample
20201 -symbol-list-types
20202@end smallexample
20203
20204List all the type names.
20205
20206@subsubheading @value{GDBN} Command
20207
20208The corresponding commands are @samp{info types} in @value{GDBN},
20209@samp{gdb_search} in @code{gdbtk}.
20210
20211@subsubheading Example
20212N.A.
20213
20214
20215@subheading The @code{-symbol-list-variables} Command
20216@findex -symbol-list-variables
20217
20218@subsubheading Synopsis
20219
20220@smallexample
20221 -symbol-list-variables
20222@end smallexample
20223
20224List all the global and static variable names.
20225
20226@subsubheading @value{GDBN} Command
20227
20228@samp{info variables} in @value{GDBN}, @samp{gdb_search} in @code{gdbtk}.
20229
20230@subsubheading Example
20231N.A.
20232
20233
20234@subheading The @code{-symbol-locate} Command
20235@findex -symbol-locate
20236
20237@subsubheading Synopsis
20238
20239@smallexample
20240 -symbol-locate
20241@end smallexample
20242
20243@subsubheading @value{GDBN} Command
20244
20245@samp{gdb_loc} in @code{gdbtk}.
20246
20247@subsubheading Example
20248N.A.
20249
20250
20251@subheading The @code{-symbol-type} Command
20252@findex -symbol-type
20253
20254@subsubheading Synopsis
20255
20256@smallexample
20257 -symbol-type @var{variable}
20258@end smallexample
20259
20260Show type of @var{variable}.
20261
20262@subsubheading @value{GDBN} Command
20263
20264The corresponding @value{GDBN} command is @samp{ptype}, @code{gdbtk} has
20265@samp{gdb_obj_variable}.
20266
20267@subsubheading Example
20268N.A.
20269
20270
20271@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
20272@node GDB/MI Target Manipulation
20273@section @sc{gdb/mi} Target Manipulation Commands
20274
20275
20276@subheading The @code{-target-attach} Command
20277@findex -target-attach
20278
20279@subsubheading Synopsis
20280
20281@smallexample
20282 -target-attach @var{pid} | @var{file}
20283@end smallexample
20284
20285Attach to a process @var{pid} or a file @var{file} outside of @value{GDBN}.
20286
20287@subsubheading @value{GDBN} command
20288
20289The corresponding @value{GDBN} command is @samp{attach}.
20290
20291@subsubheading Example
20292N.A.
20293
20294
20295@subheading The @code{-target-compare-sections} Command
20296@findex -target-compare-sections
20297
20298@subsubheading Synopsis
20299
20300@smallexample
20301 -target-compare-sections [ @var{section} ]
20302@end smallexample
20303
20304Compare data of section @var{section} on target to the exec file.
20305Without the argument, all sections are compared.
20306
20307@subsubheading @value{GDBN} Command
20308
20309The @value{GDBN} equivalent is @samp{compare-sections}.
20310
20311@subsubheading Example
20312N.A.
20313
20314
20315@subheading The @code{-target-detach} Command
20316@findex -target-detach
20317
20318@subsubheading Synopsis
20319
20320@smallexample
20321 -target-detach
20322@end smallexample
20323
20324Disconnect from the remote target. There's no output.
20325
20326@subsubheading @value{GDBN} command
20327
20328The corresponding @value{GDBN} command is @samp{detach}.
20329
20330@subsubheading Example
20331
20332@smallexample
20333(@value{GDBP})
20334-target-detach
20335^done
20336(@value{GDBP})
20337@end smallexample
20338
20339
07f31aa6
DJ
20340@subheading The @code{-target-disconnect} Command
20341@findex -target-disconnect
20342
20343@subsubheading Synopsis
20344
20345@example
20346 -target-disconnect
20347@end example
20348
20349Disconnect from the remote target. There's no output.
20350
20351@subsubheading @value{GDBN} command
20352
20353The corresponding @value{GDBN} command is @samp{disconnect}.
20354
20355@subsubheading Example
20356
20357@smallexample
20358(@value{GDBP})
20359-target-disconnect
20360^done
20361(@value{GDBP})
20362@end smallexample
20363
20364
922fbb7b
AC
20365@subheading The @code{-target-download} Command
20366@findex -target-download
20367
20368@subsubheading Synopsis
20369
20370@smallexample
20371 -target-download
20372@end smallexample
20373
20374Loads the executable onto the remote target.
20375It prints out an update message every half second, which includes the fields:
20376
20377@table @samp
20378@item section
20379The name of the section.
20380@item section-sent
20381The size of what has been sent so far for that section.
20382@item section-size
20383The size of the section.
20384@item total-sent
20385The total size of what was sent so far (the current and the previous sections).
20386@item total-size
20387The size of the overall executable to download.
20388@end table
20389
20390@noindent
20391Each message is sent as status record (@pxref{GDB/MI Output Syntax, ,
20392@sc{gdb/mi} Output Syntax}).
20393
20394In addition, it prints the name and size of the sections, as they are
20395downloaded. These messages include the following fields:
20396
20397@table @samp
20398@item section
20399The name of the section.
20400@item section-size
20401The size of the section.
20402@item total-size
20403The size of the overall executable to download.
20404@end table
20405
20406@noindent
20407At the end, a summary is printed.
20408
20409@subsubheading @value{GDBN} Command
20410
20411The corresponding @value{GDBN} command is @samp{load}.
20412
20413@subsubheading Example
20414
20415Note: each status message appears on a single line. Here the messages
20416have been broken down so that they can fit onto a page.
20417
20418@smallexample
20419(@value{GDBP})
20420-target-download
20421+download,@{section=".text",section-size="6668",total-size="9880"@}
20422+download,@{section=".text",section-sent="512",section-size="6668",
20423total-sent="512",total-size="9880"@}
20424+download,@{section=".text",section-sent="1024",section-size="6668",
20425total-sent="1024",total-size="9880"@}
20426+download,@{section=".text",section-sent="1536",section-size="6668",
20427total-sent="1536",total-size="9880"@}
20428+download,@{section=".text",section-sent="2048",section-size="6668",
20429total-sent="2048",total-size="9880"@}
20430+download,@{section=".text",section-sent="2560",section-size="6668",
20431total-sent="2560",total-size="9880"@}
20432+download,@{section=".text",section-sent="3072",section-size="6668",
20433total-sent="3072",total-size="9880"@}
20434+download,@{section=".text",section-sent="3584",section-size="6668",
20435total-sent="3584",total-size="9880"@}
20436+download,@{section=".text",section-sent="4096",section-size="6668",
20437total-sent="4096",total-size="9880"@}
20438+download,@{section=".text",section-sent="4608",section-size="6668",
20439total-sent="4608",total-size="9880"@}
20440+download,@{section=".text",section-sent="5120",section-size="6668",
20441total-sent="5120",total-size="9880"@}
20442+download,@{section=".text",section-sent="5632",section-size="6668",
20443total-sent="5632",total-size="9880"@}
20444+download,@{section=".text",section-sent="6144",section-size="6668",
20445total-sent="6144",total-size="9880"@}
20446+download,@{section=".text",section-sent="6656",section-size="6668",
20447total-sent="6656",total-size="9880"@}
20448+download,@{section=".init",section-size="28",total-size="9880"@}
20449+download,@{section=".fini",section-size="28",total-size="9880"@}
20450+download,@{section=".data",section-size="3156",total-size="9880"@}
20451+download,@{section=".data",section-sent="512",section-size="3156",
20452total-sent="7236",total-size="9880"@}
20453+download,@{section=".data",section-sent="1024",section-size="3156",
20454total-sent="7748",total-size="9880"@}
20455+download,@{section=".data",section-sent="1536",section-size="3156",
20456total-sent="8260",total-size="9880"@}
20457+download,@{section=".data",section-sent="2048",section-size="3156",
20458total-sent="8772",total-size="9880"@}
20459+download,@{section=".data",section-sent="2560",section-size="3156",
20460total-sent="9284",total-size="9880"@}
20461+download,@{section=".data",section-sent="3072",section-size="3156",
20462total-sent="9796",total-size="9880"@}
20463^done,address="0x10004",load-size="9880",transfer-rate="6586",
20464write-rate="429"
20465(@value{GDBP})
20466@end smallexample
20467
20468
20469@subheading The @code{-target-exec-status} Command
20470@findex -target-exec-status
20471
20472@subsubheading Synopsis
20473
20474@smallexample
20475 -target-exec-status
20476@end smallexample
20477
20478Provide information on the state of the target (whether it is running or
20479not, for instance).
20480
20481@subsubheading @value{GDBN} Command
20482
20483There's no equivalent @value{GDBN} command.
20484
20485@subsubheading Example
20486N.A.
20487
20488
20489@subheading The @code{-target-list-available-targets} Command
20490@findex -target-list-available-targets
20491
20492@subsubheading Synopsis
20493
20494@smallexample
20495 -target-list-available-targets
20496@end smallexample
20497
20498List the possible targets to connect to.
20499
20500@subsubheading @value{GDBN} Command
20501
20502The corresponding @value{GDBN} command is @samp{help target}.
20503
20504@subsubheading Example
20505N.A.
20506
20507
20508@subheading The @code{-target-list-current-targets} Command
20509@findex -target-list-current-targets
20510
20511@subsubheading Synopsis
20512
20513@smallexample
20514 -target-list-current-targets
20515@end smallexample
20516
20517Describe the current target.
20518
20519@subsubheading @value{GDBN} Command
20520
20521The corresponding information is printed by @samp{info file} (among
20522other things).
20523
20524@subsubheading Example
20525N.A.
20526
20527
20528@subheading The @code{-target-list-parameters} Command
20529@findex -target-list-parameters
20530
20531@subsubheading Synopsis
20532
20533@smallexample
20534 -target-list-parameters
20535@end smallexample
20536
20537@c ????
20538
20539@subsubheading @value{GDBN} Command
20540
20541No equivalent.
20542
20543@subsubheading Example
20544N.A.
20545
20546
20547@subheading The @code{-target-select} Command
20548@findex -target-select
20549
20550@subsubheading Synopsis
20551
20552@smallexample
20553 -target-select @var{type} @var{parameters @dots{}}
20554@end smallexample
20555
20556Connect @value{GDBN} to the remote target. This command takes two args:
20557
20558@table @samp
20559@item @var{type}
20560The type of target, for instance @samp{async}, @samp{remote}, etc.
20561@item @var{parameters}
20562Device names, host names and the like. @xref{Target Commands, ,
20563Commands for managing targets}, for more details.
20564@end table
20565
20566The output is a connection notification, followed by the address at
20567which the target program is, in the following form:
20568
20569@smallexample
20570^connected,addr="@var{address}",func="@var{function name}",
20571 args=[@var{arg list}]
20572@end smallexample
20573
20574@subsubheading @value{GDBN} Command
20575
20576The corresponding @value{GDBN} command is @samp{target}.
20577
20578@subsubheading Example
20579
20580@smallexample
20581(@value{GDBP})
20582-target-select async /dev/ttya
20583^connected,addr="0xfe00a300",func="??",args=[]
20584(@value{GDBP})
20585@end smallexample
20586
20587@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
20588@node GDB/MI Thread Commands
20589@section @sc{gdb/mi} Thread Commands
20590
20591
20592@subheading The @code{-thread-info} Command
20593@findex -thread-info
20594
20595@subsubheading Synopsis
20596
20597@smallexample
20598 -thread-info
20599@end smallexample
20600
20601@subsubheading @value{GDBN} command
20602
20603No equivalent.
20604
20605@subsubheading Example
20606N.A.
20607
20608
20609@subheading The @code{-thread-list-all-threads} Command
20610@findex -thread-list-all-threads
20611
20612@subsubheading Synopsis
20613
20614@smallexample
20615 -thread-list-all-threads
20616@end smallexample
20617
20618@subsubheading @value{GDBN} Command
20619
20620The equivalent @value{GDBN} command is @samp{info threads}.
20621
20622@subsubheading Example
20623N.A.
20624
20625
20626@subheading The @code{-thread-list-ids} Command
20627@findex -thread-list-ids
20628
20629@subsubheading Synopsis
20630
20631@smallexample
20632 -thread-list-ids
20633@end smallexample
20634
20635Produces a list of the currently known @value{GDBN} thread ids. At the
20636end of the list it also prints the total number of such threads.
20637
20638@subsubheading @value{GDBN} Command
20639
20640Part of @samp{info threads} supplies the same information.
20641
20642@subsubheading Example
20643
20644No threads present, besides the main process:
20645
20646@smallexample
20647(@value{GDBP})
20648-thread-list-ids
20649^done,thread-ids=@{@},number-of-threads="0"
20650(@value{GDBP})
20651@end smallexample
20652
20653
20654Several threads:
20655
20656@smallexample
20657(@value{GDBP})
20658-thread-list-ids
20659^done,thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@},
20660number-of-threads="3"
20661(@value{GDBP})
20662@end smallexample
20663
20664
20665@subheading The @code{-thread-select} Command
20666@findex -thread-select
20667
20668@subsubheading Synopsis
20669
20670@smallexample
20671 -thread-select @var{threadnum}
20672@end smallexample
20673
20674Make @var{threadnum} the current thread. It prints the number of the new
20675current thread, and the topmost frame for that thread.
20676
20677@subsubheading @value{GDBN} Command
20678
20679The corresponding @value{GDBN} command is @samp{thread}.
20680
20681@subsubheading Example
20682
20683@smallexample
20684(@value{GDBP})
20685-exec-next
20686^running
20687(@value{GDBP})
20688*stopped,reason="end-stepping-range",thread-id="2",line="187",
20689file="../../../devo/gdb/testsuite/gdb.threads/linux-dp.c"
20690(@value{GDBP})
20691-thread-list-ids
20692^done,
20693thread-ids=@{thread-id="3",thread-id="2",thread-id="1"@},
20694number-of-threads="3"
20695(@value{GDBP})
20696-thread-select 3
20697^done,new-thread-id="3",
20698frame=@{level="0",func="vprintf",
20699args=[@{name="format",value="0x8048e9c \"%*s%c %d %c\\n\""@},
20700@{name="arg",value="0x2"@}],file="vprintf.c",line="31"@}
20701(@value{GDBP})
20702@end smallexample
20703
20704@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
20705@node GDB/MI Tracepoint Commands
20706@section @sc{gdb/mi} Tracepoint Commands
20707
20708The tracepoint commands are not yet implemented.
20709
20710@c @subheading -trace-actions
20711
20712@c @subheading -trace-delete
20713
20714@c @subheading -trace-disable
20715
20716@c @subheading -trace-dump
20717
20718@c @subheading -trace-enable
20719
20720@c @subheading -trace-exists
20721
20722@c @subheading -trace-find
20723
20724@c @subheading -trace-frame-number
20725
20726@c @subheading -trace-info
20727
20728@c @subheading -trace-insert
20729
20730@c @subheading -trace-list
20731
20732@c @subheading -trace-pass-count
20733
20734@c @subheading -trace-save
20735
20736@c @subheading -trace-start
20737
20738@c @subheading -trace-stop
20739
20740
20741@c %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
20742@node GDB/MI Variable Objects
20743@section @sc{gdb/mi} Variable Objects
20744
20745
20746@subheading Motivation for Variable Objects in @sc{gdb/mi}
20747
20748For the implementation of a variable debugger window (locals, watched
20749expressions, etc.), we are proposing the adaptation of the existing code
20750used by @code{Insight}.
20751
20752The two main reasons for that are:
20753
20754@enumerate 1
20755@item
20756It has been proven in practice (it is already on its second generation).
20757
20758@item
20759It will shorten development time (needless to say how important it is
20760now).
20761@end enumerate
20762
20763The original interface was designed to be used by Tcl code, so it was
20764slightly changed so it could be used through @sc{gdb/mi}. This section
20765describes the @sc{gdb/mi} operations that will be available and gives some
20766hints about their use.
20767
20768@emph{Note}: In addition to the set of operations described here, we
20769expect the @sc{gui} implementation of a variable window to require, at
20770least, the following operations:
20771
20772@itemize @bullet
20773@item @code{-gdb-show} @code{output-radix}
20774@item @code{-stack-list-arguments}
20775@item @code{-stack-list-locals}
20776@item @code{-stack-select-frame}
20777@end itemize
20778
20779@subheading Introduction to Variable Objects in @sc{gdb/mi}
20780
20781@cindex variable objects in @sc{gdb/mi}
20782The basic idea behind variable objects is the creation of a named object
20783to represent a variable, an expression, a memory location or even a CPU
20784register. For each object created, a set of operations is available for
20785examining or changing its properties.
20786
20787Furthermore, complex data types, such as C structures, are represented
20788in a tree format. For instance, the @code{struct} type variable is the
20789root and the children will represent the struct members. If a child
20790is itself of a complex type, it will also have children of its own.
20791Appropriate language differences are handled for C, C@t{++} and Java.
20792
20793When returning the actual values of the objects, this facility allows
20794for the individual selection of the display format used in the result
20795creation. It can be chosen among: binary, decimal, hexadecimal, octal
20796and natural. Natural refers to a default format automatically
20797chosen based on the variable type (like decimal for an @code{int}, hex
20798for pointers, etc.).
20799
20800The following is the complete set of @sc{gdb/mi} operations defined to
20801access this functionality:
20802
20803@multitable @columnfractions .4 .6
20804@item @strong{Operation}
20805@tab @strong{Description}
20806
20807@item @code{-var-create}
20808@tab create a variable object
20809@item @code{-var-delete}
20810@tab delete the variable object and its children
20811@item @code{-var-set-format}
20812@tab set the display format of this variable
20813@item @code{-var-show-format}
20814@tab show the display format of this variable
20815@item @code{-var-info-num-children}
20816@tab tells how many children this object has
20817@item @code{-var-list-children}
20818@tab return a list of the object's children
20819@item @code{-var-info-type}
20820@tab show the type of this variable object
20821@item @code{-var-info-expression}
20822@tab print what this variable object represents
20823@item @code{-var-show-attributes}
20824@tab is this variable editable? does it exist here?
20825@item @code{-var-evaluate-expression}
20826@tab get the value of this variable
20827@item @code{-var-assign}
20828@tab set the value of this variable
20829@item @code{-var-update}
20830@tab update the variable and its children
20831@end multitable
20832
20833In the next subsection we describe each operation in detail and suggest
20834how it can be used.
20835
20836@subheading Description And Use of Operations on Variable Objects
20837
20838@subheading The @code{-var-create} Command
20839@findex -var-create
20840
20841@subsubheading Synopsis
20842
20843@smallexample
20844 -var-create @{@var{name} | "-"@}
20845 @{@var{frame-addr} | "*"@} @var{expression}
20846@end smallexample
20847
20848This operation creates a variable object, which allows the monitoring of
20849a variable, the result of an expression, a memory cell or a CPU
20850register.
20851
20852The @var{name} parameter is the string by which the object can be
20853referenced. It must be unique. If @samp{-} is specified, the varobj
20854system will generate a string ``varNNNNNN'' automatically. It will be
20855unique provided that one does not specify @var{name} on that format.
20856The command fails if a duplicate name is found.
20857
20858The frame under which the expression should be evaluated can be
20859specified by @var{frame-addr}. A @samp{*} indicates that the current
20860frame should be used.
20861
20862@var{expression} is any expression valid on the current language set (must not
20863begin with a @samp{*}), or one of the following:
20864
20865@itemize @bullet
20866@item
20867@samp{*@var{addr}}, where @var{addr} is the address of a memory cell
20868
20869@item
20870@samp{*@var{addr}-@var{addr}} --- a memory address range (TBD)
20871
20872@item
20873@samp{$@var{regname}} --- a CPU register name
20874@end itemize
20875
20876@subsubheading Result
20877
20878This operation returns the name, number of children and the type of the
20879object created. Type is returned as a string as the ones generated by
20880the @value{GDBN} CLI:
20881
20882@smallexample
20883 name="@var{name}",numchild="N",type="@var{type}"
20884@end smallexample
20885
20886
20887@subheading The @code{-var-delete} Command
20888@findex -var-delete
20889
20890@subsubheading Synopsis
20891
20892@smallexample
20893 -var-delete @var{name}
20894@end smallexample
20895
20896Deletes a previously created variable object and all of its children.
20897
20898Returns an error if the object @var{name} is not found.
20899
20900
20901@subheading The @code{-var-set-format} Command
20902@findex -var-set-format
20903
20904@subsubheading Synopsis
20905
20906@smallexample
20907 -var-set-format @var{name} @var{format-spec}
20908@end smallexample
20909
20910Sets the output format for the value of the object @var{name} to be
20911@var{format-spec}.
20912
20913The syntax for the @var{format-spec} is as follows:
20914
20915@smallexample
20916 @var{format-spec} @expansion{}
20917 @{binary | decimal | hexadecimal | octal | natural@}
20918@end smallexample
20919
20920
20921@subheading The @code{-var-show-format} Command
20922@findex -var-show-format
20923
20924@subsubheading Synopsis
20925
20926@smallexample
20927 -var-show-format @var{name}
20928@end smallexample
20929
20930Returns the format used to display the value of the object @var{name}.
20931
20932@smallexample
20933 @var{format} @expansion{}
20934 @var{format-spec}
20935@end smallexample
20936
20937
20938@subheading The @code{-var-info-num-children} Command
20939@findex -var-info-num-children
20940
20941@subsubheading Synopsis
20942
20943@smallexample
20944 -var-info-num-children @var{name}
20945@end smallexample
20946
20947Returns the number of children of a variable object @var{name}:
20948
20949@smallexample
20950 numchild=@var{n}
20951@end smallexample
20952
20953
20954@subheading The @code{-var-list-children} Command
20955@findex -var-list-children
20956
20957@subsubheading Synopsis
20958
20959@smallexample
bc8ced35 20960 -var-list-children [@var{print-values}] @var{name}
922fbb7b 20961@end smallexample
265eeb58 20962@anchor{-var-list-children}
922fbb7b 20963
265eeb58
NR
20964Return a list of the children of the specified variable object and
20965create variable objects for them, if they do not already exist. With
20966a single argument or if @var{print-values} has a value for of 0 or
20967@code{--no-values}, print only the names of the variables; if
20968@var{print-values} is 1 or @code{--all-values}, also print their
20969values; and if it is 2 or @code{--simple-values} print the name and
20970value for simple data types and just the name for arrays, structures
20971and unions.
bc8ced35
NR
20972
20973@subsubheading Example
922fbb7b
AC
20974
20975@smallexample
bc8ced35
NR
20976(@value{GDBP})
20977 -var-list-children n
265eeb58 20978 ^done,numchild=@var{n},children=[@{name=@var{name},
922fbb7b 20979 numchild=@var{n},type=@var{type}@},@r{(repeats N times)}]
bc8ced35
NR
20980(@value{GDBP})
20981 -var-list-children --all-values n
265eeb58 20982 ^done,numchild=@var{n},children=[@{name=@var{name},
bc8ced35 20983 numchild=@var{n},value=@var{value},type=@var{type}@},@r{(repeats N times)}]
922fbb7b
AC
20984@end smallexample
20985
20986
20987@subheading The @code{-var-info-type} Command
20988@findex -var-info-type
20989
20990@subsubheading Synopsis
20991
20992@smallexample
20993 -var-info-type @var{name}
20994@end smallexample
20995
20996Returns the type of the specified variable @var{name}. The type is
20997returned as a string in the same format as it is output by the
20998@value{GDBN} CLI:
20999
21000@smallexample
21001 type=@var{typename}
21002@end smallexample
21003
21004
21005@subheading The @code{-var-info-expression} Command
21006@findex -var-info-expression
21007
21008@subsubheading Synopsis
21009
21010@smallexample
21011 -var-info-expression @var{name}
21012@end smallexample
21013
21014Returns what is represented by the variable object @var{name}:
21015
21016@smallexample
21017 lang=@var{lang-spec},exp=@var{expression}
21018@end smallexample
21019
21020@noindent
21021where @var{lang-spec} is @code{@{"C" | "C++" | "Java"@}}.
21022
21023@subheading The @code{-var-show-attributes} Command
21024@findex -var-show-attributes
21025
21026@subsubheading Synopsis
21027
21028@smallexample
21029 -var-show-attributes @var{name}
21030@end smallexample
21031
21032List attributes of the specified variable object @var{name}:
21033
21034@smallexample
21035 status=@var{attr} [ ( ,@var{attr} )* ]
21036@end smallexample
21037
21038@noindent
21039where @var{attr} is @code{@{ @{ editable | noneditable @} | TBD @}}.
21040
21041@subheading The @code{-var-evaluate-expression} Command
21042@findex -var-evaluate-expression
21043
21044@subsubheading Synopsis
21045
21046@smallexample
21047 -var-evaluate-expression @var{name}
21048@end smallexample
21049
21050Evaluates the expression that is represented by the specified variable
21051object and returns its value as a string in the current format specified
21052for the object:
21053
21054@smallexample
21055 value=@var{value}
21056@end smallexample
21057
21058Note that one must invoke @code{-var-list-children} for a variable
21059before the value of a child variable can be evaluated.
21060
21061@subheading The @code{-var-assign} Command
21062@findex -var-assign
21063
21064@subsubheading Synopsis
21065
21066@smallexample
21067 -var-assign @var{name} @var{expression}
21068@end smallexample
21069
21070Assigns the value of @var{expression} to the variable object specified
21071by @var{name}. The object must be @samp{editable}. If the variable's
b383017d 21072value is altered by the assign, the variable will show up in any
922fbb7b
AC
21073subsequent @code{-var-update} list.
21074
21075@subsubheading Example
21076
21077@smallexample
21078(@value{GDBP})
21079-var-assign var1 3
21080^done,value="3"
21081(@value{GDBP})
21082-var-update *
21083^done,changelist=[@{name="var1",in_scope="true",type_changed="false"@}]
21084(@value{GDBP})
21085@end smallexample
21086
21087@subheading The @code{-var-update} Command
21088@findex -var-update
21089
21090@subsubheading Synopsis
21091
21092@smallexample
265eeb58 21093 -var-update [@var{print-values}] @{@var{name} | "*"@}
922fbb7b
AC
21094@end smallexample
21095
21096Update the value of the variable object @var{name} by evaluating its
21097expression after fetching all the new values from memory or registers.
265eeb58 21098A @samp{*} causes all existing variable objects to be updated. The
656d5e12
EZ
21099option @var{print-values} determines whether names both and values, or
21100just names are printed in the manner described for
21101@code{-var-list-children} (@pxref{-var-list-children}).
265eeb58
NR
21102
21103@subsubheading Example
922fbb7b 21104
265eeb58
NR
21105@smallexample
21106(@value{GDBP})
21107-var-assign var1 3
21108^done,value="3"
21109(@value{GDBP})
21110-var-update --all-values var1
21111^done,changelist=[@{name="var1",value="3",in_scope="true",
21112type_changed="false"@}]
21113(@value{GDBP})
21114@end smallexample
922fbb7b
AC
21115
21116@node Annotations
21117@chapter @value{GDBN} Annotations
21118
086432e2
AC
21119This chapter describes annotations in @value{GDBN}. Annotations were
21120designed to interface @value{GDBN} to graphical user interfaces or other
21121similar programs which want to interact with @value{GDBN} at a
922fbb7b
AC
21122relatively high level.
21123
086432e2
AC
21124The annotation mechanism has largely been superseeded by @sc{gdb/mi}
21125(@pxref{GDB/MI}).
21126
922fbb7b
AC
21127@ignore
21128This is Edition @value{EDITION}, @value{DATE}.
21129@end ignore
21130
21131@menu
21132* Annotations Overview:: What annotations are; the general syntax.
922fbb7b
AC
21133* Prompting:: Annotations marking @value{GDBN}'s need for input.
21134* Errors:: Annotations for error messages.
922fbb7b
AC
21135* Invalidation:: Some annotations describe things now invalid.
21136* Annotations for Running::
21137 Whether the program is running, how it stopped, etc.
21138* Source Annotations:: Annotations describing source code.
922fbb7b
AC
21139@end menu
21140
21141@node Annotations Overview
21142@section What is an Annotation?
21143@cindex annotations
21144
922fbb7b
AC
21145Annotations start with a newline character, two @samp{control-z}
21146characters, and the name of the annotation. If there is no additional
21147information associated with this annotation, the name of the annotation
21148is followed immediately by a newline. If there is additional
21149information, the name of the annotation is followed by a space, the
21150additional information, and a newline. The additional information
21151cannot contain newline characters.
21152
21153Any output not beginning with a newline and two @samp{control-z}
21154characters denotes literal output from @value{GDBN}. Currently there is
21155no need for @value{GDBN} to output a newline followed by two
21156@samp{control-z} characters, but if there was such a need, the
21157annotations could be extended with an @samp{escape} annotation which
21158means those three characters as output.
21159
086432e2
AC
21160The annotation @var{level}, which is specified using the
21161@option{--annotate} command line option (@pxref{Mode Options}), controls
21162how much information @value{GDBN} prints together with its prompt,
21163values of expressions, source lines, and other types of output. Level 0
21164is for no anntations, level 1 is for use when @value{GDBN} is run as a
21165subprocess of @sc{gnu} Emacs, level 3 is the maximum annotation suitable
21166for programs that control @value{GDBN}, and level 2 annotations have
21167been made obsolete (@pxref{Limitations, , Limitations of the Annotation
09d4efe1
EZ
21168Interface, annotate, GDB's Obsolete Annotations}).
21169
21170@table @code
21171@kindex set annotate
21172@item set annotate @var{level}
e09f16f9 21173The @value{GDBN} command @code{set annotate} sets the level of
09d4efe1 21174annotations to the specified @var{level}.
9c16f35a
EZ
21175
21176@item show annotate
21177@kindex show annotate
21178Show the current annotation level.
09d4efe1
EZ
21179@end table
21180
21181This chapter describes level 3 annotations.
086432e2 21182
922fbb7b
AC
21183A simple example of starting up @value{GDBN} with annotations is:
21184
21185@smallexample
086432e2
AC
21186$ @kbd{gdb --annotate=3}
21187GNU gdb 6.0
21188Copyright 2003 Free Software Foundation, Inc.
922fbb7b
AC
21189GDB is free software, covered by the GNU General Public License,
21190and you are welcome to change it and/or distribute copies of it
21191under certain conditions.
21192Type "show copying" to see the conditions.
21193There is absolutely no warranty for GDB. Type "show warranty"
21194for details.
086432e2 21195This GDB was configured as "i386-pc-linux-gnu"
922fbb7b
AC
21196
21197^Z^Zpre-prompt
f7dc1244 21198(@value{GDBP})
922fbb7b 21199^Z^Zprompt
086432e2 21200@kbd{quit}
922fbb7b
AC
21201
21202^Z^Zpost-prompt
b383017d 21203$
922fbb7b
AC
21204@end smallexample
21205
21206Here @samp{quit} is input to @value{GDBN}; the rest is output from
21207@value{GDBN}. The three lines beginning @samp{^Z^Z} (where @samp{^Z}
21208denotes a @samp{control-z} character) are annotations; the rest is
21209output from @value{GDBN}.
21210
922fbb7b
AC
21211@node Prompting
21212@section Annotation for @value{GDBN} Input
21213
21214@cindex annotations for prompts
21215When @value{GDBN} prompts for input, it annotates this fact so it is possible
21216to know when to send output, when the output from a given command is
21217over, etc.
21218
21219Different kinds of input each have a different @dfn{input type}. Each
21220input type has three annotations: a @code{pre-} annotation, which
21221denotes the beginning of any prompt which is being output, a plain
21222annotation, which denotes the end of the prompt, and then a @code{post-}
21223annotation which denotes the end of any echo which may (or may not) be
21224associated with the input. For example, the @code{prompt} input type
21225features the following annotations:
21226
21227@smallexample
21228^Z^Zpre-prompt
21229^Z^Zprompt
21230^Z^Zpost-prompt
21231@end smallexample
21232
21233The input types are
21234
21235@table @code
21236@findex pre-prompt
21237@findex prompt
21238@findex post-prompt
21239@item prompt
21240When @value{GDBN} is prompting for a command (the main @value{GDBN} prompt).
21241
21242@findex pre-commands
21243@findex commands
21244@findex post-commands
21245@item commands
21246When @value{GDBN} prompts for a set of commands, like in the @code{commands}
21247command. The annotations are repeated for each command which is input.
21248
21249@findex pre-overload-choice
21250@findex overload-choice
21251@findex post-overload-choice
21252@item overload-choice
21253When @value{GDBN} wants the user to select between various overloaded functions.
21254
21255@findex pre-query
21256@findex query
21257@findex post-query
21258@item query
21259When @value{GDBN} wants the user to confirm a potentially dangerous operation.
21260
21261@findex pre-prompt-for-continue
21262@findex prompt-for-continue
21263@findex post-prompt-for-continue
21264@item prompt-for-continue
21265When @value{GDBN} is asking the user to press return to continue. Note: Don't
21266expect this to work well; instead use @code{set height 0} to disable
21267prompting. This is because the counting of lines is buggy in the
21268presence of annotations.
21269@end table
21270
21271@node Errors
21272@section Errors
21273@cindex annotations for errors, warnings and interrupts
21274
21275@findex quit
21276@smallexample
21277^Z^Zquit
21278@end smallexample
21279
21280This annotation occurs right before @value{GDBN} responds to an interrupt.
21281
21282@findex error
21283@smallexample
21284^Z^Zerror
21285@end smallexample
21286
21287This annotation occurs right before @value{GDBN} responds to an error.
21288
21289Quit and error annotations indicate that any annotations which @value{GDBN} was
21290in the middle of may end abruptly. For example, if a
21291@code{value-history-begin} annotation is followed by a @code{error}, one
21292cannot expect to receive the matching @code{value-history-end}. One
21293cannot expect not to receive it either, however; an error annotation
21294does not necessarily mean that @value{GDBN} is immediately returning all the way
21295to the top level.
21296
21297@findex error-begin
21298A quit or error annotation may be preceded by
21299
21300@smallexample
21301^Z^Zerror-begin
21302@end smallexample
21303
21304Any output between that and the quit or error annotation is the error
21305message.
21306
21307Warning messages are not yet annotated.
21308@c If we want to change that, need to fix warning(), type_error(),
21309@c range_error(), and possibly other places.
21310
922fbb7b
AC
21311@node Invalidation
21312@section Invalidation Notices
21313
21314@cindex annotations for invalidation messages
21315The following annotations say that certain pieces of state may have
21316changed.
21317
21318@table @code
21319@findex frames-invalid
21320@item ^Z^Zframes-invalid
21321
21322The frames (for example, output from the @code{backtrace} command) may
21323have changed.
21324
21325@findex breakpoints-invalid
21326@item ^Z^Zbreakpoints-invalid
21327
21328The breakpoints may have changed. For example, the user just added or
21329deleted a breakpoint.
21330@end table
21331
21332@node Annotations for Running
21333@section Running the Program
21334@cindex annotations for running programs
21335
21336@findex starting
21337@findex stopping
21338When the program starts executing due to a @value{GDBN} command such as
b383017d 21339@code{step} or @code{continue},
922fbb7b
AC
21340
21341@smallexample
21342^Z^Zstarting
21343@end smallexample
21344
b383017d 21345is output. When the program stops,
922fbb7b
AC
21346
21347@smallexample
21348^Z^Zstopped
21349@end smallexample
21350
21351is output. Before the @code{stopped} annotation, a variety of
21352annotations describe how the program stopped.
21353
21354@table @code
21355@findex exited
21356@item ^Z^Zexited @var{exit-status}
21357The program exited, and @var{exit-status} is the exit status (zero for
21358successful exit, otherwise nonzero).
21359
21360@findex signalled
21361@findex signal-name
21362@findex signal-name-end
21363@findex signal-string
21364@findex signal-string-end
21365@item ^Z^Zsignalled
21366The program exited with a signal. After the @code{^Z^Zsignalled}, the
21367annotation continues:
21368
21369@smallexample
21370@var{intro-text}
21371^Z^Zsignal-name
21372@var{name}
21373^Z^Zsignal-name-end
21374@var{middle-text}
21375^Z^Zsignal-string
21376@var{string}
21377^Z^Zsignal-string-end
21378@var{end-text}
21379@end smallexample
21380
21381@noindent
21382where @var{name} is the name of the signal, such as @code{SIGILL} or
21383@code{SIGSEGV}, and @var{string} is the explanation of the signal, such
21384as @code{Illegal Instruction} or @code{Segmentation fault}.
21385@var{intro-text}, @var{middle-text}, and @var{end-text} are for the
21386user's benefit and have no particular format.
21387
21388@findex signal
21389@item ^Z^Zsignal
21390The syntax of this annotation is just like @code{signalled}, but @value{GDBN} is
21391just saying that the program received the signal, not that it was
21392terminated with it.
21393
21394@findex breakpoint
21395@item ^Z^Zbreakpoint @var{number}
21396The program hit breakpoint number @var{number}.
21397
21398@findex watchpoint
21399@item ^Z^Zwatchpoint @var{number}
21400The program hit watchpoint number @var{number}.
21401@end table
21402
21403@node Source Annotations
21404@section Displaying Source
21405@cindex annotations for source display
21406
21407@findex source
21408The following annotation is used instead of displaying source code:
21409
21410@smallexample
21411^Z^Zsource @var{filename}:@var{line}:@var{character}:@var{middle}:@var{addr}
21412@end smallexample
21413
21414where @var{filename} is an absolute file name indicating which source
21415file, @var{line} is the line number within that file (where 1 is the
21416first line in the file), @var{character} is the character position
21417within the file (where 0 is the first character in the file) (for most
21418debug formats this will necessarily point to the beginning of a line),
21419@var{middle} is @samp{middle} if @var{addr} is in the middle of the
21420line, or @samp{beg} if @var{addr} is at the beginning of the line, and
21421@var{addr} is the address in the target program associated with the
21422source which is being displayed. @var{addr} is in the form @samp{0x}
21423followed by one or more lowercase hex digits (note that this does not
21424depend on the language).
21425
8e04817f
AC
21426@node GDB Bugs
21427@chapter Reporting Bugs in @value{GDBN}
21428@cindex bugs in @value{GDBN}
21429@cindex reporting bugs in @value{GDBN}
c906108c 21430
8e04817f 21431Your bug reports play an essential role in making @value{GDBN} reliable.
c906108c 21432
8e04817f
AC
21433Reporting a bug may help you by bringing a solution to your problem, or it
21434may not. But in any case the principal function of a bug report is to help
21435the entire community by making the next version of @value{GDBN} work better. Bug
21436reports are your contribution to the maintenance of @value{GDBN}.
c906108c 21437
8e04817f
AC
21438In order for a bug report to serve its purpose, you must include the
21439information that enables us to fix the bug.
c4555f82
SC
21440
21441@menu
8e04817f
AC
21442* Bug Criteria:: Have you found a bug?
21443* Bug Reporting:: How to report bugs
c4555f82
SC
21444@end menu
21445
8e04817f
AC
21446@node Bug Criteria
21447@section Have you found a bug?
21448@cindex bug criteria
c4555f82 21449
8e04817f 21450If you are not sure whether you have found a bug, here are some guidelines:
c4555f82
SC
21451
21452@itemize @bullet
8e04817f
AC
21453@cindex fatal signal
21454@cindex debugger crash
21455@cindex crash of debugger
c4555f82 21456@item
8e04817f
AC
21457If the debugger gets a fatal signal, for any input whatever, that is a
21458@value{GDBN} bug. Reliable debuggers never crash.
21459
21460@cindex error on valid input
21461@item
21462If @value{GDBN} produces an error message for valid input, that is a
21463bug. (Note that if you're cross debugging, the problem may also be
21464somewhere in the connection to the target.)
c4555f82 21465
8e04817f 21466@cindex invalid input
c4555f82 21467@item
8e04817f
AC
21468If @value{GDBN} does not produce an error message for invalid input,
21469that is a bug. However, you should note that your idea of
21470``invalid input'' might be our idea of ``an extension'' or ``support
21471for traditional practice''.
21472
21473@item
21474If you are an experienced user of debugging tools, your suggestions
21475for improvement of @value{GDBN} are welcome in any case.
c4555f82
SC
21476@end itemize
21477
8e04817f
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21478@node Bug Reporting
21479@section How to report bugs
21480@cindex bug reports
21481@cindex @value{GDBN} bugs, reporting
21482
21483A number of companies and individuals offer support for @sc{gnu} products.
21484If you obtained @value{GDBN} from a support organization, we recommend you
21485contact that organization first.
21486
21487You can find contact information for many support companies and
21488individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
21489distribution.
21490@c should add a web page ref...
21491
129188f6
AC
21492In any event, we also recommend that you submit bug reports for
21493@value{GDBN}. The prefered method is to submit them directly using
21494@uref{http://www.gnu.org/software/gdb/bugs/, @value{GDBN}'s Bugs web
21495page}. Alternatively, the @email{bug-gdb@@gnu.org, e-mail gateway} can
21496be used.
8e04817f
AC
21497
21498@strong{Do not send bug reports to @samp{info-gdb}, or to
21499@samp{help-gdb}, or to any newsgroups.} Most users of @value{GDBN} do
21500not want to receive bug reports. Those that do have arranged to receive
21501@samp{bug-gdb}.
21502
21503The mailing list @samp{bug-gdb} has a newsgroup @samp{gnu.gdb.bug} which
21504serves as a repeater. The mailing list and the newsgroup carry exactly
21505the same messages. Often people think of posting bug reports to the
21506newsgroup instead of mailing them. This appears to work, but it has one
21507problem which can be crucial: a newsgroup posting often lacks a mail
21508path back to the sender. Thus, if we need to ask for more information,
21509we may be unable to reach you. For this reason, it is better to send
21510bug reports to the mailing list.
c4555f82 21511
8e04817f
AC
21512The fundamental principle of reporting bugs usefully is this:
21513@strong{report all the facts}. If you are not sure whether to state a
21514fact or leave it out, state it!
c4555f82 21515
8e04817f
AC
21516Often people omit facts because they think they know what causes the
21517problem and assume that some details do not matter. Thus, you might
21518assume that the name of the variable you use in an example does not matter.
21519Well, probably it does not, but one cannot be sure. Perhaps the bug is a
21520stray memory reference which happens to fetch from the location where that
21521name is stored in memory; perhaps, if the name were different, the contents
21522of that location would fool the debugger into doing the right thing despite
21523the bug. Play it safe and give a specific, complete example. That is the
21524easiest thing for you to do, and the most helpful.
c4555f82 21525
8e04817f
AC
21526Keep in mind that the purpose of a bug report is to enable us to fix the
21527bug. It may be that the bug has been reported previously, but neither
21528you nor we can know that unless your bug report is complete and
21529self-contained.
c4555f82 21530
8e04817f
AC
21531Sometimes people give a few sketchy facts and ask, ``Does this ring a
21532bell?'' Those bug reports are useless, and we urge everyone to
21533@emph{refuse to respond to them} except to chide the sender to report
21534bugs properly.
21535
21536To enable us to fix the bug, you should include all these things:
c4555f82
SC
21537
21538@itemize @bullet
21539@item
8e04817f
AC
21540The version of @value{GDBN}. @value{GDBN} announces it if you start
21541with no arguments; you can also print it at any time using @code{show
21542version}.
c4555f82 21543
8e04817f
AC
21544Without this, we will not know whether there is any point in looking for
21545the bug in the current version of @value{GDBN}.
c4555f82
SC
21546
21547@item
8e04817f
AC
21548The type of machine you are using, and the operating system name and
21549version number.
c4555f82
SC
21550
21551@item
c1468174 21552What compiler (and its version) was used to compile @value{GDBN}---e.g.@:
8e04817f 21553``@value{GCC}--2.8.1''.
c4555f82
SC
21554
21555@item
8e04817f 21556What compiler (and its version) was used to compile the program you are
c1468174 21557debugging---e.g.@: ``@value{GCC}--2.8.1'', or ``HP92453-01 A.10.32.03 HP
8e04817f
AC
21558C Compiler''. For GCC, you can say @code{gcc --version} to get this
21559information; for other compilers, see the documentation for those
21560compilers.
c4555f82 21561
8e04817f
AC
21562@item
21563The command arguments you gave the compiler to compile your example and
21564observe the bug. For example, did you use @samp{-O}? To guarantee
21565you will not omit something important, list them all. A copy of the
21566Makefile (or the output from make) is sufficient.
c4555f82 21567
8e04817f
AC
21568If we were to try to guess the arguments, we would probably guess wrong
21569and then we might not encounter the bug.
c4555f82 21570
8e04817f
AC
21571@item
21572A complete input script, and all necessary source files, that will
21573reproduce the bug.
c4555f82 21574
8e04817f
AC
21575@item
21576A description of what behavior you observe that you believe is
21577incorrect. For example, ``It gets a fatal signal.''
c4555f82 21578
8e04817f
AC
21579Of course, if the bug is that @value{GDBN} gets a fatal signal, then we
21580will certainly notice it. But if the bug is incorrect output, we might
21581not notice unless it is glaringly wrong. You might as well not give us
21582a chance to make a mistake.
c4555f82 21583
8e04817f
AC
21584Even if the problem you experience is a fatal signal, you should still
21585say so explicitly. Suppose something strange is going on, such as, your
21586copy of @value{GDBN} is out of synch, or you have encountered a bug in
21587the C library on your system. (This has happened!) Your copy might
21588crash and ours would not. If you told us to expect a crash, then when
21589ours fails to crash, we would know that the bug was not happening for
21590us. If you had not told us to expect a crash, then we would not be able
21591to draw any conclusion from our observations.
c4555f82 21592
e0c07bf0
MC
21593@pindex script
21594@cindex recording a session script
21595To collect all this information, you can use a session recording program
21596such as @command{script}, which is available on many Unix systems.
21597Just run your @value{GDBN} session inside @command{script} and then
21598include the @file{typescript} file with your bug report.
21599
21600Another way to record a @value{GDBN} session is to run @value{GDBN}
21601inside Emacs and then save the entire buffer to a file.
21602
8e04817f
AC
21603@item
21604If you wish to suggest changes to the @value{GDBN} source, send us context
21605diffs. If you even discuss something in the @value{GDBN} source, refer to
21606it by context, not by line number.
c4555f82 21607
8e04817f
AC
21608The line numbers in our development sources will not match those in your
21609sources. Your line numbers would convey no useful information to us.
c4555f82 21610
8e04817f 21611@end itemize
c4555f82 21612
8e04817f 21613Here are some things that are not necessary:
c4555f82 21614
8e04817f
AC
21615@itemize @bullet
21616@item
21617A description of the envelope of the bug.
c4555f82 21618
8e04817f
AC
21619Often people who encounter a bug spend a lot of time investigating
21620which changes to the input file will make the bug go away and which
21621changes will not affect it.
c4555f82 21622
8e04817f
AC
21623This is often time consuming and not very useful, because the way we
21624will find the bug is by running a single example under the debugger
21625with breakpoints, not by pure deduction from a series of examples.
21626We recommend that you save your time for something else.
c4555f82 21627
8e04817f
AC
21628Of course, if you can find a simpler example to report @emph{instead}
21629of the original one, that is a convenience for us. Errors in the
21630output will be easier to spot, running under the debugger will take
21631less time, and so on.
c4555f82 21632
8e04817f
AC
21633However, simplification is not vital; if you do not want to do this,
21634report the bug anyway and send us the entire test case you used.
c4555f82 21635
8e04817f
AC
21636@item
21637A patch for the bug.
c4555f82 21638
8e04817f
AC
21639A patch for the bug does help us if it is a good one. But do not omit
21640the necessary information, such as the test case, on the assumption that
21641a patch is all we need. We might see problems with your patch and decide
21642to fix the problem another way, or we might not understand it at all.
c4555f82 21643
8e04817f
AC
21644Sometimes with a program as complicated as @value{GDBN} it is very hard to
21645construct an example that will make the program follow a certain path
21646through the code. If you do not send us the example, we will not be able
21647to construct one, so we will not be able to verify that the bug is fixed.
c4555f82 21648
8e04817f
AC
21649And if we cannot understand what bug you are trying to fix, or why your
21650patch should be an improvement, we will not install it. A test case will
21651help us to understand.
c4555f82 21652
8e04817f
AC
21653@item
21654A guess about what the bug is or what it depends on.
c4555f82 21655
8e04817f
AC
21656Such guesses are usually wrong. Even we cannot guess right about such
21657things without first using the debugger to find the facts.
21658@end itemize
c4555f82 21659
8e04817f
AC
21660@c The readline documentation is distributed with the readline code
21661@c and consists of the two following files:
21662@c rluser.texinfo
21663@c inc-hist.texinfo
21664@c Use -I with makeinfo to point to the appropriate directory,
21665@c environment var TEXINPUTS with TeX.
21666@include rluser.texinfo
21667@include inc-hist.texinfo
c4555f82 21668
c4555f82 21669
8e04817f
AC
21670@node Formatting Documentation
21671@appendix Formatting Documentation
c4555f82 21672
8e04817f
AC
21673@cindex @value{GDBN} reference card
21674@cindex reference card
21675The @value{GDBN} 4 release includes an already-formatted reference card, ready
21676for printing with PostScript or Ghostscript, in the @file{gdb}
21677subdirectory of the main source directory@footnote{In
21678@file{gdb-@value{GDBVN}/gdb/refcard.ps} of the version @value{GDBVN}
21679release.}. If you can use PostScript or Ghostscript with your printer,
21680you can print the reference card immediately with @file{refcard.ps}.
c4555f82 21681
8e04817f
AC
21682The release also includes the source for the reference card. You
21683can format it, using @TeX{}, by typing:
c4555f82 21684
474c8240 21685@smallexample
8e04817f 21686make refcard.dvi
474c8240 21687@end smallexample
c4555f82 21688
8e04817f
AC
21689The @value{GDBN} reference card is designed to print in @dfn{landscape}
21690mode on US ``letter'' size paper;
21691that is, on a sheet 11 inches wide by 8.5 inches
21692high. You will need to specify this form of printing as an option to
21693your @sc{dvi} output program.
c4555f82 21694
8e04817f 21695@cindex documentation
c4555f82 21696
8e04817f
AC
21697All the documentation for @value{GDBN} comes as part of the machine-readable
21698distribution. The documentation is written in Texinfo format, which is
21699a documentation system that uses a single source file to produce both
21700on-line information and a printed manual. You can use one of the Info
21701formatting commands to create the on-line version of the documentation
21702and @TeX{} (or @code{texi2roff}) to typeset the printed version.
c4555f82 21703
8e04817f
AC
21704@value{GDBN} includes an already formatted copy of the on-line Info
21705version of this manual in the @file{gdb} subdirectory. The main Info
21706file is @file{gdb-@value{GDBVN}/gdb/gdb.info}, and it refers to
21707subordinate files matching @samp{gdb.info*} in the same directory. If
21708necessary, you can print out these files, or read them with any editor;
21709but they are easier to read using the @code{info} subsystem in @sc{gnu}
21710Emacs or the standalone @code{info} program, available as part of the
21711@sc{gnu} Texinfo distribution.
c4555f82 21712
8e04817f
AC
21713If you want to format these Info files yourself, you need one of the
21714Info formatting programs, such as @code{texinfo-format-buffer} or
21715@code{makeinfo}.
c4555f82 21716
8e04817f
AC
21717If you have @code{makeinfo} installed, and are in the top level
21718@value{GDBN} source directory (@file{gdb-@value{GDBVN}}, in the case of
21719version @value{GDBVN}), you can make the Info file by typing:
c4555f82 21720
474c8240 21721@smallexample
8e04817f
AC
21722cd gdb
21723make gdb.info
474c8240 21724@end smallexample
c4555f82 21725
8e04817f
AC
21726If you want to typeset and print copies of this manual, you need @TeX{},
21727a program to print its @sc{dvi} output files, and @file{texinfo.tex}, the
21728Texinfo definitions file.
c4555f82 21729
8e04817f
AC
21730@TeX{} is a typesetting program; it does not print files directly, but
21731produces output files called @sc{dvi} files. To print a typeset
21732document, you need a program to print @sc{dvi} files. If your system
21733has @TeX{} installed, chances are it has such a program. The precise
21734command to use depends on your system; @kbd{lpr -d} is common; another
21735(for PostScript devices) is @kbd{dvips}. The @sc{dvi} print command may
21736require a file name without any extension or a @samp{.dvi} extension.
c4555f82 21737
8e04817f
AC
21738@TeX{} also requires a macro definitions file called
21739@file{texinfo.tex}. This file tells @TeX{} how to typeset a document
21740written in Texinfo format. On its own, @TeX{} cannot either read or
21741typeset a Texinfo file. @file{texinfo.tex} is distributed with GDB
21742and is located in the @file{gdb-@var{version-number}/texinfo}
21743directory.
c4555f82 21744
8e04817f
AC
21745If you have @TeX{} and a @sc{dvi} printer program installed, you can
21746typeset and print this manual. First switch to the the @file{gdb}
21747subdirectory of the main source directory (for example, to
21748@file{gdb-@value{GDBVN}/gdb}) and type:
c4555f82 21749
474c8240 21750@smallexample
8e04817f 21751make gdb.dvi
474c8240 21752@end smallexample
c4555f82 21753
8e04817f 21754Then give @file{gdb.dvi} to your @sc{dvi} printing program.
c4555f82 21755
8e04817f
AC
21756@node Installing GDB
21757@appendix Installing @value{GDBN}
21758@cindex configuring @value{GDBN}
21759@cindex installation
94e91d6d 21760@cindex configuring @value{GDBN}, and source tree subdirectories
c4555f82 21761
8e04817f
AC
21762@value{GDBN} comes with a @code{configure} script that automates the process
21763of preparing @value{GDBN} for installation; you can then use @code{make} to
21764build the @code{gdb} program.
21765@iftex
21766@c irrelevant in info file; it's as current as the code it lives with.
21767@footnote{If you have a more recent version of @value{GDBN} than @value{GDBVN},
21768look at the @file{README} file in the sources; we may have improved the
21769installation procedures since publishing this manual.}
21770@end iftex
c4555f82 21771
8e04817f
AC
21772The @value{GDBN} distribution includes all the source code you need for
21773@value{GDBN} in a single directory, whose name is usually composed by
21774appending the version number to @samp{gdb}.
c4555f82 21775
8e04817f
AC
21776For example, the @value{GDBN} version @value{GDBVN} distribution is in the
21777@file{gdb-@value{GDBVN}} directory. That directory contains:
c4555f82 21778
8e04817f
AC
21779@table @code
21780@item gdb-@value{GDBVN}/configure @r{(and supporting files)}
21781script for configuring @value{GDBN} and all its supporting libraries
c4555f82 21782
8e04817f
AC
21783@item gdb-@value{GDBVN}/gdb
21784the source specific to @value{GDBN} itself
c4555f82 21785
8e04817f
AC
21786@item gdb-@value{GDBVN}/bfd
21787source for the Binary File Descriptor library
c906108c 21788
8e04817f
AC
21789@item gdb-@value{GDBVN}/include
21790@sc{gnu} include files
c906108c 21791
8e04817f
AC
21792@item gdb-@value{GDBVN}/libiberty
21793source for the @samp{-liberty} free software library
c906108c 21794
8e04817f
AC
21795@item gdb-@value{GDBVN}/opcodes
21796source for the library of opcode tables and disassemblers
c906108c 21797
8e04817f
AC
21798@item gdb-@value{GDBVN}/readline
21799source for the @sc{gnu} command-line interface
c906108c 21800
8e04817f
AC
21801@item gdb-@value{GDBVN}/glob
21802source for the @sc{gnu} filename pattern-matching subroutine
c906108c 21803
8e04817f
AC
21804@item gdb-@value{GDBVN}/mmalloc
21805source for the @sc{gnu} memory-mapped malloc package
21806@end table
c906108c 21807
8e04817f
AC
21808The simplest way to configure and build @value{GDBN} is to run @code{configure}
21809from the @file{gdb-@var{version-number}} source directory, which in
21810this example is the @file{gdb-@value{GDBVN}} directory.
c906108c 21811
8e04817f
AC
21812First switch to the @file{gdb-@var{version-number}} source directory
21813if you are not already in it; then run @code{configure}. Pass the
21814identifier for the platform on which @value{GDBN} will run as an
21815argument.
c906108c 21816
8e04817f 21817For example:
c906108c 21818
474c8240 21819@smallexample
8e04817f
AC
21820cd gdb-@value{GDBVN}
21821./configure @var{host}
21822make
474c8240 21823@end smallexample
c906108c 21824
8e04817f
AC
21825@noindent
21826where @var{host} is an identifier such as @samp{sun4} or
21827@samp{decstation}, that identifies the platform where @value{GDBN} will run.
21828(You can often leave off @var{host}; @code{configure} tries to guess the
21829correct value by examining your system.)
c906108c 21830
8e04817f
AC
21831Running @samp{configure @var{host}} and then running @code{make} builds the
21832@file{bfd}, @file{readline}, @file{mmalloc}, and @file{libiberty}
21833libraries, then @code{gdb} itself. The configured source files, and the
21834binaries, are left in the corresponding source directories.
c906108c 21835
8e04817f
AC
21836@need 750
21837@code{configure} is a Bourne-shell (@code{/bin/sh}) script; if your
21838system does not recognize this automatically when you run a different
21839shell, you may need to run @code{sh} on it explicitly:
c906108c 21840
474c8240 21841@smallexample
8e04817f 21842sh configure @var{host}
474c8240 21843@end smallexample
c906108c 21844
8e04817f
AC
21845If you run @code{configure} from a directory that contains source
21846directories for multiple libraries or programs, such as the
21847@file{gdb-@value{GDBVN}} source directory for version @value{GDBVN}, @code{configure}
21848creates configuration files for every directory level underneath (unless
21849you tell it not to, with the @samp{--norecursion} option).
21850
94e91d6d
MC
21851You should run the @code{configure} script from the top directory in the
21852source tree, the @file{gdb-@var{version-number}} directory. If you run
21853@code{configure} from one of the subdirectories, you will configure only
21854that subdirectory. That is usually not what you want. In particular,
21855if you run the first @code{configure} from the @file{gdb} subdirectory
21856of the @file{gdb-@var{version-number}} directory, you will omit the
21857configuration of @file{bfd}, @file{readline}, and other sibling
21858directories of the @file{gdb} subdirectory. This leads to build errors
21859about missing include files such as @file{bfd/bfd.h}.
c906108c 21860
8e04817f
AC
21861You can install @code{@value{GDBP}} anywhere; it has no hardwired paths.
21862However, you should make sure that the shell on your path (named by
21863the @samp{SHELL} environment variable) is publicly readable. Remember
21864that @value{GDBN} uses the shell to start your program---some systems refuse to
21865let @value{GDBN} debug child processes whose programs are not readable.
c906108c 21866
8e04817f
AC
21867@menu
21868* Separate Objdir:: Compiling @value{GDBN} in another directory
21869* Config Names:: Specifying names for hosts and targets
21870* Configure Options:: Summary of options for configure
21871@end menu
c906108c 21872
8e04817f
AC
21873@node Separate Objdir
21874@section Compiling @value{GDBN} in another directory
c906108c 21875
8e04817f
AC
21876If you want to run @value{GDBN} versions for several host or target machines,
21877you need a different @code{gdb} compiled for each combination of
21878host and target. @code{configure} is designed to make this easy by
21879allowing you to generate each configuration in a separate subdirectory,
21880rather than in the source directory. If your @code{make} program
21881handles the @samp{VPATH} feature (@sc{gnu} @code{make} does), running
21882@code{make} in each of these directories builds the @code{gdb}
21883program specified there.
c906108c 21884
8e04817f
AC
21885To build @code{gdb} in a separate directory, run @code{configure}
21886with the @samp{--srcdir} option to specify where to find the source.
21887(You also need to specify a path to find @code{configure}
21888itself from your working directory. If the path to @code{configure}
21889would be the same as the argument to @samp{--srcdir}, you can leave out
21890the @samp{--srcdir} option; it is assumed.)
c906108c 21891
8e04817f
AC
21892For example, with version @value{GDBVN}, you can build @value{GDBN} in a
21893separate directory for a Sun 4 like this:
c906108c 21894
474c8240 21895@smallexample
8e04817f
AC
21896@group
21897cd gdb-@value{GDBVN}
21898mkdir ../gdb-sun4
21899cd ../gdb-sun4
21900../gdb-@value{GDBVN}/configure sun4
21901make
21902@end group
474c8240 21903@end smallexample
c906108c 21904
8e04817f
AC
21905When @code{configure} builds a configuration using a remote source
21906directory, it creates a tree for the binaries with the same structure
21907(and using the same names) as the tree under the source directory. In
21908the example, you'd find the Sun 4 library @file{libiberty.a} in the
21909directory @file{gdb-sun4/libiberty}, and @value{GDBN} itself in
21910@file{gdb-sun4/gdb}.
c906108c 21911
94e91d6d
MC
21912Make sure that your path to the @file{configure} script has just one
21913instance of @file{gdb} in it. If your path to @file{configure} looks
21914like @file{../gdb-@value{GDBVN}/gdb/configure}, you are configuring only
21915one subdirectory of @value{GDBN}, not the whole package. This leads to
21916build errors about missing include files such as @file{bfd/bfd.h}.
21917
8e04817f
AC
21918One popular reason to build several @value{GDBN} configurations in separate
21919directories is to configure @value{GDBN} for cross-compiling (where
21920@value{GDBN} runs on one machine---the @dfn{host}---while debugging
21921programs that run on another machine---the @dfn{target}).
21922You specify a cross-debugging target by
21923giving the @samp{--target=@var{target}} option to @code{configure}.
c906108c 21924
8e04817f
AC
21925When you run @code{make} to build a program or library, you must run
21926it in a configured directory---whatever directory you were in when you
21927called @code{configure} (or one of its subdirectories).
c906108c 21928
8e04817f
AC
21929The @code{Makefile} that @code{configure} generates in each source
21930directory also runs recursively. If you type @code{make} in a source
21931directory such as @file{gdb-@value{GDBVN}} (or in a separate configured
21932directory configured with @samp{--srcdir=@var{dirname}/gdb-@value{GDBVN}}), you
21933will build all the required libraries, and then build GDB.
c906108c 21934
8e04817f
AC
21935When you have multiple hosts or targets configured in separate
21936directories, you can run @code{make} on them in parallel (for example,
21937if they are NFS-mounted on each of the hosts); they will not interfere
21938with each other.
c906108c 21939
8e04817f
AC
21940@node Config Names
21941@section Specifying names for hosts and targets
c906108c 21942
8e04817f
AC
21943The specifications used for hosts and targets in the @code{configure}
21944script are based on a three-part naming scheme, but some short predefined
21945aliases are also supported. The full naming scheme encodes three pieces
21946of information in the following pattern:
c906108c 21947
474c8240 21948@smallexample
8e04817f 21949@var{architecture}-@var{vendor}-@var{os}
474c8240 21950@end smallexample
c906108c 21951
8e04817f
AC
21952For example, you can use the alias @code{sun4} as a @var{host} argument,
21953or as the value for @var{target} in a @code{--target=@var{target}}
21954option. The equivalent full name is @samp{sparc-sun-sunos4}.
c906108c 21955
8e04817f
AC
21956The @code{configure} script accompanying @value{GDBN} does not provide
21957any query facility to list all supported host and target names or
21958aliases. @code{configure} calls the Bourne shell script
21959@code{config.sub} to map abbreviations to full names; you can read the
21960script, if you wish, or you can use it to test your guesses on
21961abbreviations---for example:
c906108c 21962
8e04817f
AC
21963@smallexample
21964% sh config.sub i386-linux
21965i386-pc-linux-gnu
21966% sh config.sub alpha-linux
21967alpha-unknown-linux-gnu
21968% sh config.sub hp9k700
21969hppa1.1-hp-hpux
21970% sh config.sub sun4
21971sparc-sun-sunos4.1.1
21972% sh config.sub sun3
21973m68k-sun-sunos4.1.1
21974% sh config.sub i986v
21975Invalid configuration `i986v': machine `i986v' not recognized
21976@end smallexample
c906108c 21977
8e04817f
AC
21978@noindent
21979@code{config.sub} is also distributed in the @value{GDBN} source
21980directory (@file{gdb-@value{GDBVN}}, for version @value{GDBVN}).
d700128c 21981
8e04817f
AC
21982@node Configure Options
21983@section @code{configure} options
c906108c 21984
8e04817f
AC
21985Here is a summary of the @code{configure} options and arguments that
21986are most often useful for building @value{GDBN}. @code{configure} also has
21987several other options not listed here. @inforef{What Configure
21988Does,,configure.info}, for a full explanation of @code{configure}.
c906108c 21989
474c8240 21990@smallexample
8e04817f
AC
21991configure @r{[}--help@r{]}
21992 @r{[}--prefix=@var{dir}@r{]}
21993 @r{[}--exec-prefix=@var{dir}@r{]}
21994 @r{[}--srcdir=@var{dirname}@r{]}
21995 @r{[}--norecursion@r{]} @r{[}--rm@r{]}
21996 @r{[}--target=@var{target}@r{]}
21997 @var{host}
474c8240 21998@end smallexample
c906108c 21999
8e04817f
AC
22000@noindent
22001You may introduce options with a single @samp{-} rather than
22002@samp{--} if you prefer; but you may abbreviate option names if you use
22003@samp{--}.
c906108c 22004
8e04817f
AC
22005@table @code
22006@item --help
22007Display a quick summary of how to invoke @code{configure}.
c906108c 22008
8e04817f
AC
22009@item --prefix=@var{dir}
22010Configure the source to install programs and files under directory
22011@file{@var{dir}}.
c906108c 22012
8e04817f
AC
22013@item --exec-prefix=@var{dir}
22014Configure the source to install programs under directory
22015@file{@var{dir}}.
c906108c 22016
8e04817f
AC
22017@c avoid splitting the warning from the explanation:
22018@need 2000
22019@item --srcdir=@var{dirname}
22020@strong{Warning: using this option requires @sc{gnu} @code{make}, or another
22021@code{make} that implements the @code{VPATH} feature.}@*
22022Use this option to make configurations in directories separate from the
22023@value{GDBN} source directories. Among other things, you can use this to
22024build (or maintain) several configurations simultaneously, in separate
22025directories. @code{configure} writes configuration specific files in
22026the current directory, but arranges for them to use the source in the
22027directory @var{dirname}. @code{configure} creates directories under
22028the working directory in parallel to the source directories below
22029@var{dirname}.
c906108c 22030
8e04817f
AC
22031@item --norecursion
22032Configure only the directory level where @code{configure} is executed; do not
22033propagate configuration to subdirectories.
c906108c 22034
8e04817f
AC
22035@item --target=@var{target}
22036Configure @value{GDBN} for cross-debugging programs running on the specified
22037@var{target}. Without this option, @value{GDBN} is configured to debug
22038programs that run on the same machine (@var{host}) as @value{GDBN} itself.
c906108c 22039
8e04817f 22040There is no convenient way to generate a list of all available targets.
c906108c 22041
8e04817f
AC
22042@item @var{host} @dots{}
22043Configure @value{GDBN} to run on the specified @var{host}.
c906108c 22044
8e04817f
AC
22045There is no convenient way to generate a list of all available hosts.
22046@end table
c906108c 22047
8e04817f
AC
22048There are many other options available as well, but they are generally
22049needed for special purposes only.
c906108c 22050
8e04817f
AC
22051@node Maintenance Commands
22052@appendix Maintenance Commands
22053@cindex maintenance commands
22054@cindex internal commands
c906108c 22055
8e04817f 22056In addition to commands intended for @value{GDBN} users, @value{GDBN}
09d4efe1
EZ
22057includes a number of commands intended for @value{GDBN} developers,
22058that are not documented elsewhere in this manual. These commands are
da316a69
EZ
22059provided here for reference. (For commands that turn on debugging
22060messages, see @ref{Debugging Output}.)
c906108c 22061
8e04817f 22062@table @code
09d4efe1
EZ
22063@kindex maint agent
22064@item maint agent @var{expression}
22065Translate the given @var{expression} into remote agent bytecodes.
22066This command is useful for debugging the Agent Expression mechanism
22067(@pxref{Agent Expressions}).
22068
8e04817f
AC
22069@kindex maint info breakpoints
22070@item @anchor{maint info breakpoints}maint info breakpoints
22071Using the same format as @samp{info breakpoints}, display both the
22072breakpoints you've set explicitly, and those @value{GDBN} is using for
22073internal purposes. Internal breakpoints are shown with negative
22074breakpoint numbers. The type column identifies what kind of breakpoint
22075is shown:
c906108c 22076
8e04817f
AC
22077@table @code
22078@item breakpoint
22079Normal, explicitly set breakpoint.
c906108c 22080
8e04817f
AC
22081@item watchpoint
22082Normal, explicitly set watchpoint.
c906108c 22083
8e04817f
AC
22084@item longjmp
22085Internal breakpoint, used to handle correctly stepping through
22086@code{longjmp} calls.
c906108c 22087
8e04817f
AC
22088@item longjmp resume
22089Internal breakpoint at the target of a @code{longjmp}.
c906108c 22090
8e04817f
AC
22091@item until
22092Temporary internal breakpoint used by the @value{GDBN} @code{until} command.
c906108c 22093
8e04817f
AC
22094@item finish
22095Temporary internal breakpoint used by the @value{GDBN} @code{finish} command.
c906108c 22096
8e04817f
AC
22097@item shlib events
22098Shared library events.
c906108c 22099
8e04817f 22100@end table
c906108c 22101
09d4efe1
EZ
22102@kindex maint check-symtabs
22103@item maint check-symtabs
22104Check the consistency of psymtabs and symtabs.
22105
22106@kindex maint cplus first_component
22107@item maint cplus first_component @var{name}
22108Print the first C@t{++} class/namespace component of @var{name}.
22109
22110@kindex maint cplus namespace
22111@item maint cplus namespace
22112Print the list of possible C@t{++} namespaces.
22113
22114@kindex maint demangle
22115@item maint demangle @var{name}
22116Demangle a C@t{++} or Objective-C manled @var{name}.
22117
22118@kindex maint deprecate
22119@kindex maint undeprecate
22120@cindex deprecated commands
22121@item maint deprecate @var{command} @r{[}@var{replacement}@r{]}
22122@itemx maint undeprecate @var{command}
22123Deprecate or undeprecate the named @var{command}. Deprecated commands
22124cause @value{GDBN} to issue a warning when you use them. The optional
22125argument @var{replacement} says which newer command should be used in
22126favor of the deprecated one; if it is given, @value{GDBN} will mention
22127the replacement as part of the warning.
22128
22129@kindex maint dump-me
22130@item maint dump-me
721c2651 22131@cindex @code{SIGQUIT} signal, dump core of @value{GDBN}
09d4efe1 22132Cause a fatal signal in the debugger and force it to dump its core.
721c2651
EZ
22133This is supported only on systems which support aborting a program
22134with the @code{SIGQUIT} signal.
09d4efe1 22135
8d30a00d
AC
22136@kindex maint internal-error
22137@kindex maint internal-warning
09d4efe1
EZ
22138@item maint internal-error @r{[}@var{message-text}@r{]}
22139@itemx maint internal-warning @r{[}@var{message-text}@r{]}
8d30a00d
AC
22140Cause @value{GDBN} to call the internal function @code{internal_error}
22141or @code{internal_warning} and hence behave as though an internal error
22142or internal warning has been detected. In addition to reporting the
22143internal problem, these functions give the user the opportunity to
22144either quit @value{GDBN} or create a core file of the current
22145@value{GDBN} session.
22146
09d4efe1
EZ
22147These commands take an optional parameter @var{message-text} that is
22148used as the text of the error or warning message.
22149
22150Here's an example of using @code{indernal-error}:
22151
8d30a00d 22152@smallexample
f7dc1244 22153(@value{GDBP}) @kbd{maint internal-error testing, 1, 2}
8d30a00d
AC
22154@dots{}/maint.c:121: internal-error: testing, 1, 2
22155A problem internal to GDB has been detected. Further
22156debugging may prove unreliable.
22157Quit this debugging session? (y or n) @kbd{n}
22158Create a core file? (y or n) @kbd{n}
f7dc1244 22159(@value{GDBP})
8d30a00d
AC
22160@end smallexample
22161
09d4efe1
EZ
22162@kindex maint packet
22163@item maint packet @var{text}
22164If @value{GDBN} is talking to an inferior via the serial protocol,
22165then this command sends the string @var{text} to the inferior, and
22166displays the response packet. @value{GDBN} supplies the initial
22167@samp{$} character, the terminating @samp{#} character, and the
22168checksum.
22169
22170@kindex maint print architecture
22171@item maint print architecture @r{[}@var{file}@r{]}
22172Print the entire architecture configuration. The optional argument
22173@var{file} names the file where the output goes.
8d30a00d 22174
00905d52
AC
22175@kindex maint print dummy-frames
22176@item maint print dummy-frames
00905d52
AC
22177Prints the contents of @value{GDBN}'s internal dummy-frame stack.
22178
22179@smallexample
f7dc1244 22180(@value{GDBP}) @kbd{b add}
00905d52 22181@dots{}
f7dc1244 22182(@value{GDBP}) @kbd{print add(2,3)}
00905d52
AC
22183Breakpoint 2, add (a=2, b=3) at @dots{}
2218458 return (a + b);
22185The program being debugged stopped while in a function called from GDB.
22186@dots{}
f7dc1244 22187(@value{GDBP}) @kbd{maint print dummy-frames}
00905d52
AC
221880x1a57c80: pc=0x01014068 fp=0x0200bddc sp=0x0200bdd6
22189 top=0x0200bdd4 id=@{stack=0x200bddc,code=0x101405c@}
22190 call_lo=0x01014000 call_hi=0x01014001
f7dc1244 22191(@value{GDBP})
00905d52
AC
22192@end smallexample
22193
22194Takes an optional file parameter.
22195
0680b120
AC
22196@kindex maint print registers
22197@kindex maint print raw-registers
22198@kindex maint print cooked-registers
617073a9 22199@kindex maint print register-groups
09d4efe1
EZ
22200@item maint print registers @r{[}@var{file}@r{]}
22201@itemx maint print raw-registers @r{[}@var{file}@r{]}
22202@itemx maint print cooked-registers @r{[}@var{file}@r{]}
22203@itemx maint print register-groups @r{[}@var{file}@r{]}
0680b120
AC
22204Print @value{GDBN}'s internal register data structures.
22205
617073a9
AC
22206The command @code{maint print raw-registers} includes the contents of
22207the raw register cache; the command @code{maint print cooked-registers}
22208includes the (cooked) value of all registers; and the command
22209@code{maint print register-groups} includes the groups that each
22210register is a member of. @xref{Registers,, Registers, gdbint,
22211@value{GDBN} Internals}.
0680b120 22212
09d4efe1
EZ
22213These commands take an optional parameter, a file name to which to
22214write the information.
0680b120 22215
617073a9 22216@kindex maint print reggroups
09d4efe1
EZ
22217@item maint print reggroups @r{[}@var{file}@r{]}
22218Print @value{GDBN}'s internal register group data structures. The
22219optional argument @var{file} tells to what file to write the
22220information.
617073a9 22221
09d4efe1 22222The register groups info looks like this:
617073a9
AC
22223
22224@smallexample
f7dc1244 22225(@value{GDBP}) @kbd{maint print reggroups}
b383017d
RM
22226 Group Type
22227 general user
22228 float user
22229 all user
22230 vector user
22231 system user
22232 save internal
22233 restore internal
617073a9
AC
22234@end smallexample
22235
09d4efe1
EZ
22236@kindex flushregs
22237@item flushregs
22238This command forces @value{GDBN} to flush its internal register cache.
22239
22240@kindex maint print objfiles
22241@cindex info for known object files
22242@item maint print objfiles
22243Print a dump of all known object files. For each object file, this
22244command prints its name, address in memory, and all of its psymtabs
22245and symtabs.
22246
22247@kindex maint print statistics
22248@cindex bcache statistics
22249@item maint print statistics
22250This command prints, for each object file in the program, various data
22251about that object file followed by the byte cache (@dfn{bcache})
22252statistics for the object file. The objfile data includes the number
22253of minimal, partical, full, and stabs symbols, the number of types
22254defined by the objfile, the number of as yet unexpanded psym tables,
22255the number of line tables and string tables, and the amount of memory
22256used by the various tables. The bcache statistics include the counts,
22257sizes, and counts of duplicates of all and unique objects, max,
22258average, and median entry size, total memory used and its overhead and
22259savings, and various measures of the hash table size and chain
22260lengths.
22261
22262@kindex maint print type
22263@cindex type chain of a data type
22264@item maint print type @var{expr}
22265Print the type chain for a type specified by @var{expr}. The argument
22266can be either a type name or a symbol. If it is a symbol, the type of
22267that symbol is described. The type chain produced by this command is
22268a recursive definition of the data type as stored in @value{GDBN}'s
22269data structures, including its flags and contained types.
22270
22271@kindex maint set dwarf2 max-cache-age
22272@kindex maint show dwarf2 max-cache-age
22273@item maint set dwarf2 max-cache-age
22274@itemx maint show dwarf2 max-cache-age
22275Control the DWARF 2 compilation unit cache.
22276
22277@cindex DWARF 2 compilation units cache
22278In object files with inter-compilation-unit references, such as those
22279produced by the GCC option @samp{-feliminate-dwarf2-dups}, the DWARF 2
22280reader needs to frequently refer to previously read compilation units.
22281This setting controls how long a compilation unit will remain in the
22282cache if it is not referenced. A higher limit means that cached
22283compilation units will be stored in memory longer, and more total
22284memory will be used. Setting it to zero disables caching, which will
22285slow down @value{GDBN} startup, but reduce memory consumption.
22286
e7ba9c65
DJ
22287@kindex maint set profile
22288@kindex maint show profile
22289@cindex profiling GDB
22290@item maint set profile
22291@itemx maint show profile
22292Control profiling of @value{GDBN}.
22293
22294Profiling will be disabled until you use the @samp{maint set profile}
22295command to enable it. When you enable profiling, the system will begin
22296collecting timing and execution count data; when you disable profiling or
22297exit @value{GDBN}, the results will be written to a log file. Remember that
22298if you use profiling, @value{GDBN} will overwrite the profiling log file
22299(often called @file{gmon.out}). If you have a record of important profiling
22300data in a @file{gmon.out} file, be sure to move it to a safe location.
22301
22302Configuring with @samp{--enable-profiling} arranges for @value{GDBN} to be
b383017d 22303compiled with the @samp{-pg} compiler option.
e7ba9c65 22304
09d4efe1
EZ
22305@kindex maint show-debug-regs
22306@cindex x86 hardware debug registers
22307@item maint show-debug-regs
22308Control whether to show variables that mirror the x86 hardware debug
22309registers. Use @code{ON} to enable, @code{OFF} to disable. If
22310enabled, the debug registers values are shown when GDB inserts or
22311removes a hardware breakpoint or watchpoint, and when the inferior
22312triggers a hardware-assisted breakpoint or watchpoint.
22313
22314@kindex maint space
22315@cindex memory used by commands
22316@item maint space
22317Control whether to display memory usage for each command. If set to a
22318nonzero value, @value{GDBN} will display how much memory each command
22319took, following the command's own output. This can also be requested
22320by invoking @value{GDBN} with the @option{--statistics} command-line
22321switch (@pxref{Mode Options}).
22322
22323@kindex maint time
22324@cindex time of command execution
22325@item maint time
22326Control whether to display the execution time for each command. If
22327set to a nonzero value, @value{GDBN} will display how much time it
22328took to execute each command, following the command's own output.
22329This can also be requested by invoking @value{GDBN} with the
22330@option{--statistics} command-line switch (@pxref{Mode Options}).
22331
22332@kindex maint translate-address
22333@item maint translate-address @r{[}@var{section}@r{]} @var{addr}
22334Find the symbol stored at the location specified by the address
22335@var{addr} and an optional section name @var{section}. If found,
22336@value{GDBN} prints the name of the closest symbol and an offset from
22337the symbol's location to the specified address. This is similar to
22338the @code{info address} command (@pxref{Symbols}), except that this
22339command also allows to find symbols in other sections.
ae038cb0 22340
8e04817f 22341@end table
c906108c 22342
9c16f35a
EZ
22343The following command is useful for non-interactive invocations of
22344@value{GDBN}, such as in the test suite.
22345
22346@table @code
22347@item set watchdog @var{nsec}
22348@kindex set watchdog
22349@cindex watchdog timer
22350@cindex timeout for commands
22351Set the maximum number of seconds @value{GDBN} will wait for the
22352target operation to finish. If this time expires, @value{GDBN}
22353reports and error and the command is aborted.
22354
22355@item show watchdog
22356Show the current setting of the target wait timeout.
22357@end table
c906108c 22358
e0ce93ac 22359@node Remote Protocol
8e04817f 22360@appendix @value{GDBN} Remote Serial Protocol
c906108c 22361
ee2d5c50
AC
22362@menu
22363* Overview::
22364* Packets::
22365* Stop Reply Packets::
22366* General Query Packets::
22367* Register Packet Format::
9d29849a 22368* Tracepoint Packets::
9a6253be 22369* Interrupts::
ee2d5c50 22370* Examples::
0ce1b118 22371* File-I/O remote protocol extension::
ee2d5c50
AC
22372@end menu
22373
22374@node Overview
22375@section Overview
22376
8e04817f
AC
22377There may be occasions when you need to know something about the
22378protocol---for example, if there is only one serial port to your target
22379machine, you might want your program to do something special if it
22380recognizes a packet meant for @value{GDBN}.
c906108c 22381
d2c6833e 22382In the examples below, @samp{->} and @samp{<-} are used to indicate
8e04817f 22383transmitted and received data respectfully.
c906108c 22384
8e04817f
AC
22385@cindex protocol, @value{GDBN} remote serial
22386@cindex serial protocol, @value{GDBN} remote
22387@cindex remote serial protocol
22388All @value{GDBN} commands and responses (other than acknowledgments) are
22389sent as a @var{packet}. A @var{packet} is introduced with the character
22390@samp{$}, the actual @var{packet-data}, and the terminating character
22391@samp{#} followed by a two-digit @var{checksum}:
c906108c 22392
474c8240 22393@smallexample
8e04817f 22394@code{$}@var{packet-data}@code{#}@var{checksum}
474c8240 22395@end smallexample
8e04817f 22396@noindent
c906108c 22397
8e04817f
AC
22398@cindex checksum, for @value{GDBN} remote
22399@noindent
22400The two-digit @var{checksum} is computed as the modulo 256 sum of all
22401characters between the leading @samp{$} and the trailing @samp{#} (an
22402eight bit unsigned checksum).
c906108c 22403
8e04817f
AC
22404Implementors should note that prior to @value{GDBN} 5.0 the protocol
22405specification also included an optional two-digit @var{sequence-id}:
c906108c 22406
474c8240 22407@smallexample
8e04817f 22408@code{$}@var{sequence-id}@code{:}@var{packet-data}@code{#}@var{checksum}
474c8240 22409@end smallexample
c906108c 22410
8e04817f
AC
22411@cindex sequence-id, for @value{GDBN} remote
22412@noindent
22413That @var{sequence-id} was appended to the acknowledgment. @value{GDBN}
22414has never output @var{sequence-id}s. Stubs that handle packets added
22415since @value{GDBN} 5.0 must not accept @var{sequence-id}.
c906108c 22416
8e04817f
AC
22417@cindex acknowledgment, for @value{GDBN} remote
22418When either the host or the target machine receives a packet, the first
22419response expected is an acknowledgment: either @samp{+} (to indicate
22420the package was received correctly) or @samp{-} (to request
22421retransmission):
c906108c 22422
474c8240 22423@smallexample
d2c6833e
AC
22424-> @code{$}@var{packet-data}@code{#}@var{checksum}
22425<- @code{+}
474c8240 22426@end smallexample
8e04817f 22427@noindent
53a5351d 22428
8e04817f
AC
22429The host (@value{GDBN}) sends @var{command}s, and the target (the
22430debugging stub incorporated in your program) sends a @var{response}. In
22431the case of step and continue @var{command}s, the response is only sent
22432when the operation has completed (the target has again stopped).
c906108c 22433
8e04817f
AC
22434@var{packet-data} consists of a sequence of characters with the
22435exception of @samp{#} and @samp{$} (see @samp{X} packet for additional
22436exceptions).
c906108c 22437
8e04817f 22438Fields within the packet should be separated using @samp{,} @samp{;} or
ee2d5c50 22439@cindex remote protocol, field separator
8e04817f 22440@samp{:}. Except where otherwise noted all numbers are represented in
ee2d5c50 22441@sc{hex} with leading zeros suppressed.
c906108c 22442
8e04817f
AC
22443Implementors should note that prior to @value{GDBN} 5.0, the character
22444@samp{:} could not appear as the third character in a packet (as it
22445would potentially conflict with the @var{sequence-id}).
c906108c 22446
8e04817f
AC
22447Response @var{data} can be run-length encoded to save space. A @samp{*}
22448means that the next character is an @sc{ascii} encoding giving a repeat count
22449which stands for that many repetitions of the character preceding the
22450@samp{*}. The encoding is @code{n+29}, yielding a printable character
22451where @code{n >=3} (which is where rle starts to win). The printable
22452characters @samp{$}, @samp{#}, @samp{+} and @samp{-} or with a numeric
22453value greater than 126 should not be used.
c906108c 22454
8e04817f 22455So:
474c8240 22456@smallexample
8e04817f 22457"@code{0* }"
474c8240 22458@end smallexample
8e04817f
AC
22459@noindent
22460means the same as "0000".
c906108c 22461
8e04817f
AC
22462The error response returned for some packets includes a two character
22463error number. That number is not well defined.
c906108c 22464
f8da2bff 22465@cindex empty response, for unsupported packets
8e04817f
AC
22466For any @var{command} not supported by the stub, an empty response
22467(@samp{$#00}) should be returned. That way it is possible to extend the
22468protocol. A newer @value{GDBN} can tell if a packet is supported based
22469on that response.
c906108c 22470
b383017d
RM
22471A stub is required to support the @samp{g}, @samp{G}, @samp{m}, @samp{M},
22472@samp{c}, and @samp{s} @var{command}s. All other @var{command}s are
8e04817f 22473optional.
c906108c 22474
ee2d5c50
AC
22475@node Packets
22476@section Packets
22477
22478The following table provides a complete list of all currently defined
22479@var{command}s and their corresponding response @var{data}.
9c16f35a
EZ
22480@xref{File-I/O remote protocol extension}, for details about the File
22481I/O extension of the remote protocol.
ee2d5c50 22482
b8ff78ce
JB
22483Each packet's description has a template showing the packet's overall
22484syntax, followed by an explanation of the packet's meaning. We
22485include spaces in some of the templates for clarity; these are not
22486part of the packet's syntax. No @value{GDBN} packet uses spaces to
22487separate its components. For example, a template like @samp{foo
22488@var{bar} @var{baz}} describes a packet beginning with the three ASCII
22489bytes @samp{foo}, followed by a @var{bar}, followed directly by a
22490@var{baz}. GDB does not transmit a space character between the
22491@samp{foo} and the @var{bar}, or between the @var{bar} and the
22492@var{baz}.
22493
8ffe2530
JB
22494Note that all packet forms beginning with an upper- or lower-case
22495letter, other than those described here, are reserved for future use.
22496
b8ff78ce 22497Here are the packet descriptions.
ee2d5c50 22498
b8ff78ce 22499@table @samp
ee2d5c50 22500
b8ff78ce
JB
22501@item !
22502@cindex @samp{!} packet
8e04817f
AC
22503Enable extended mode. In extended mode, the remote server is made
22504persistent. The @samp{R} packet is used to restart the program being
22505debugged.
ee2d5c50
AC
22506
22507Reply:
22508@table @samp
22509@item OK
8e04817f 22510The remote target both supports and has enabled extended mode.
ee2d5c50 22511@end table
c906108c 22512
b8ff78ce
JB
22513@item ?
22514@cindex @samp{?} packet
ee2d5c50
AC
22515Indicate the reason the target halted. The reply is the same as for
22516step and continue.
c906108c 22517
ee2d5c50
AC
22518Reply:
22519@xref{Stop Reply Packets}, for the reply specifications.
22520
b8ff78ce
JB
22521@item A @var{arglen},@var{argnum},@var{arg},@dots{}
22522@cindex @samp{A} packet
22523Initialized @code{argv[]} array passed into program. @var{arglen}
22524specifies the number of bytes in the hex encoded byte stream
22525@var{arg}. See @code{gdbserver} for more details.
ee2d5c50
AC
22526
22527Reply:
22528@table @samp
22529@item OK
b8ff78ce
JB
22530The arguments were set.
22531@item E @var{NN}
22532An error occurred.
ee2d5c50
AC
22533@end table
22534
b8ff78ce
JB
22535@item b @var{baud}
22536@cindex @samp{b} packet
22537(Don't use this packet; its behavior is not well-defined.)
ee2d5c50
AC
22538Change the serial line speed to @var{baud}.
22539
22540JTC: @emph{When does the transport layer state change? When it's
22541received, or after the ACK is transmitted. In either case, there are
22542problems if the command or the acknowledgment packet is dropped.}
22543
22544Stan: @emph{If people really wanted to add something like this, and get
22545it working for the first time, they ought to modify ser-unix.c to send
22546some kind of out-of-band message to a specially-setup stub and have the
22547switch happen "in between" packets, so that from remote protocol's point
22548of view, nothing actually happened.}
22549
b8ff78ce
JB
22550@item B @var{addr},@var{mode}
22551@cindex @samp{B} packet
8e04817f 22552Set (@var{mode} is @samp{S}) or clear (@var{mode} is @samp{C}) a
2f870471
AC
22553breakpoint at @var{addr}.
22554
b8ff78ce 22555Don't use this packet. Use the @samp{Z} and @samp{z} packets instead
2f870471 22556(@pxref{insert breakpoint or watchpoint packet}).
c906108c 22557
b8ff78ce
JB
22558@item c @var{addr}
22559@cindex @samp{c} packet
22560Continue. @var{addr} is address to resume. If @var{addr} is omitted,
22561resume at current address.
c906108c 22562
ee2d5c50
AC
22563Reply:
22564@xref{Stop Reply Packets}, for the reply specifications.
22565
b8ff78ce
JB
22566@item C @var{sig};@var{addr}
22567@cindex @samp{C} packet
8e04817f 22568Continue with signal @var{sig} (hex signal number). If
b8ff78ce 22569@samp{;@var{addr}} is omitted, resume at same address.
c906108c 22570
ee2d5c50
AC
22571Reply:
22572@xref{Stop Reply Packets}, for the reply specifications.
c906108c 22573
b8ff78ce
JB
22574@item d
22575@cindex @samp{d} packet
ee2d5c50
AC
22576Toggle debug flag.
22577
b8ff78ce
JB
22578Don't use this packet; instead, define a general set packet
22579(@pxref{General Query Packets}).
ee2d5c50 22580
b8ff78ce
JB
22581@item D
22582@cindex @samp{D} packet
ee2d5c50 22583Detach @value{GDBN} from the remote system. Sent to the remote target
07f31aa6 22584before @value{GDBN} disconnects via the @code{detach} command.
ee2d5c50
AC
22585
22586Reply:
22587@table @samp
10fac096
NW
22588@item OK
22589for success
b8ff78ce 22590@item E @var{NN}
10fac096 22591for an error
ee2d5c50 22592@end table
c906108c 22593
b8ff78ce
JB
22594@item F @var{RC},@var{EE},@var{CF};@var{XX}
22595@cindex @samp{F} packet
22596A reply from @value{GDBN} to an @samp{F} packet sent by the target.
22597This is part of the File-I/O protocol extension. @xref{File-I/O
22598remote protocol extension}, for the specification.
ee2d5c50 22599
b8ff78ce 22600@item g
ee2d5c50 22601@anchor{read registers packet}
b8ff78ce 22602@cindex @samp{g} packet
ee2d5c50
AC
22603Read general registers.
22604
22605Reply:
22606@table @samp
22607@item @var{XX@dots{}}
8e04817f
AC
22608Each byte of register data is described by two hex digits. The bytes
22609with the register are transmitted in target byte order. The size of
b8ff78ce 22610each register and their position within the @samp{g} packet are
12c266ea 22611determined by the @value{GDBN} internal macros
b8ff78ce
JB
22612@code{DEPRECATED_REGISTER_RAW_SIZE} and @code{REGISTER_NAME} macros. The
22613specification of several standard @samp{g} packets is specified below.
22614@item E @var{NN}
ee2d5c50
AC
22615for an error.
22616@end table
c906108c 22617
b8ff78ce
JB
22618@item G @var{XX@dots{}}
22619@cindex @samp{G} packet
22620Write general registers. @xref{read registers packet}, for a
22621description of the @var{XX@dots{}} data.
ee2d5c50
AC
22622
22623Reply:
22624@table @samp
22625@item OK
22626for success
b8ff78ce 22627@item E @var{NN}
ee2d5c50
AC
22628for an error
22629@end table
22630
b8ff78ce
JB
22631@item H @var{c} @var{t}
22632@cindex @samp{H} packet
8e04817f 22633Set thread for subsequent operations (@samp{m}, @samp{M}, @samp{g},
ee2d5c50
AC
22634@samp{G}, et.al.). @var{c} depends on the operation to be performed: it
22635should be @samp{c} for step and continue operations, @samp{g} for other
b8ff78ce
JB
22636operations. The thread designator @var{t} may be @samp{-1}, meaning all
22637the threads, a thread number, or @samp{0} which means pick any thread.
ee2d5c50
AC
22638
22639Reply:
22640@table @samp
22641@item OK
22642for success
b8ff78ce 22643@item E @var{NN}
ee2d5c50
AC
22644for an error
22645@end table
c906108c 22646
8e04817f
AC
22647@c FIXME: JTC:
22648@c 'H': How restrictive (or permissive) is the thread model. If a
22649@c thread is selected and stopped, are other threads allowed
22650@c to continue to execute? As I mentioned above, I think the
22651@c semantics of each command when a thread is selected must be
22652@c described. For example:
22653@c
22654@c 'g': If the stub supports threads and a specific thread is
22655@c selected, returns the register block from that thread;
22656@c otherwise returns current registers.
22657@c
22658@c 'G' If the stub supports threads and a specific thread is
22659@c selected, sets the registers of the register block of
22660@c that thread; otherwise sets current registers.
c906108c 22661
b8ff78ce 22662@item i @r{[}@var{addr}@r{[},@var{nnn}@r{]]}
ee2d5c50 22663@anchor{cycle step packet}
b8ff78ce
JB
22664@cindex @samp{i} packet
22665Step the remote target by a single clock cycle. If @samp{,@var{nnn}} is
8e04817f
AC
22666present, cycle step @var{nnn} cycles. If @var{addr} is present, cycle
22667step starting at that address.
c906108c 22668
b8ff78ce
JB
22669@item I
22670@cindex @samp{I} packet
22671Signal, then cycle step. @xref{step with signal packet}. @xref{cycle
22672step packet}.
ee2d5c50 22673
b8ff78ce
JB
22674@item k
22675@cindex @samp{k} packet
22676Kill request.
c906108c 22677
ac282366 22678FIXME: @emph{There is no description of how to operate when a specific
ee2d5c50
AC
22679thread context has been selected (i.e.@: does 'k' kill only that
22680thread?)}.
c906108c 22681
b8ff78ce
JB
22682@item m @var{addr},@var{length}
22683@cindex @samp{m} packet
8e04817f 22684Read @var{length} bytes of memory starting at address @var{addr}.
fb031cdf
JB
22685Note that @var{addr} may not be aligned to any particular boundary.
22686
22687The stub need not use any particular size or alignment when gathering
22688data from memory for the response; even if @var{addr} is word-aligned
22689and @var{length} is a multiple of the word size, the stub is free to
22690use byte accesses, or not. For this reason, this packet may not be
22691suitable for accessing memory-mapped I/O devices.
c43c5473
JB
22692@cindex alignment of remote memory accesses
22693@cindex size of remote memory accesses
22694@cindex memory, alignment and size of remote accesses
c906108c 22695
ee2d5c50
AC
22696Reply:
22697@table @samp
22698@item @var{XX@dots{}}
b8ff78ce
JB
22699Memory contents; each byte is transmitted as a two-digit hexidecimal
22700number. The reply may contain fewer bytes than requested if the
22701server was able to read only part of the region of memory.
22702@item E @var{NN}
ee2d5c50
AC
22703@var{NN} is errno
22704@end table
22705
b8ff78ce
JB
22706@item M @var{addr},@var{length}:@var{XX@dots{}}
22707@cindex @samp{M} packet
8e04817f 22708Write @var{length} bytes of memory starting at address @var{addr}.
b8ff78ce
JB
22709@var{XX@dots{}} is the data; each byte is transmitted as a two-digit
22710hexidecimal number.
ee2d5c50
AC
22711
22712Reply:
22713@table @samp
22714@item OK
22715for success
b8ff78ce 22716@item E @var{NN}
8e04817f
AC
22717for an error (this includes the case where only part of the data was
22718written).
ee2d5c50 22719@end table
c906108c 22720
b8ff78ce
JB
22721@item p @var{n}
22722@cindex @samp{p} packet
22723Read the value of register @var{n}; @var{n} is in hex.
2e868123
AC
22724@xref{read registers packet}, for a description of how the returned
22725register value is encoded.
ee2d5c50
AC
22726
22727Reply:
22728@table @samp
2e868123
AC
22729@item @var{XX@dots{}}
22730the register's value
b8ff78ce 22731@item E @var{NN}
2e868123
AC
22732for an error
22733@item
22734Indicating an unrecognized @var{query}.
ee2d5c50
AC
22735@end table
22736
b8ff78ce 22737@item P @var{n@dots{}}=@var{r@dots{}}
ee2d5c50 22738@anchor{write register packet}
b8ff78ce
JB
22739@cindex @samp{P} packet
22740Write register @var{n@dots{}} with value @var{r@dots{}}. The register
22741number @var{n} is in hexidecimal, and @var{r@dots{}} contains two hex
8e04817f 22742digits for each byte in the register (target byte order).
c906108c 22743
ee2d5c50
AC
22744Reply:
22745@table @samp
22746@item OK
22747for success
b8ff78ce 22748@item E @var{NN}
ee2d5c50
AC
22749for an error
22750@end table
22751
5f3bebba
JB
22752@item q @var{name} @var{params}@dots{}
22753@itemx Q @var{name} @var{params}@dots{}
b8ff78ce 22754@cindex @samp{q} packet
b8ff78ce 22755@cindex @samp{Q} packet
5f3bebba
JB
22756General query (@samp{q}) and set (@samp{Q}). These packets are
22757described fully in @ref{General Query Packets}.
c906108c 22758
b8ff78ce
JB
22759@item r
22760@cindex @samp{r} packet
8e04817f 22761Reset the entire system.
c906108c 22762
b8ff78ce 22763Don't use this packet; use the @samp{R} packet instead.
ee2d5c50 22764
b8ff78ce
JB
22765@item R @var{XX}
22766@cindex @samp{R} packet
8e04817f
AC
22767Restart the program being debugged. @var{XX}, while needed, is ignored.
22768This packet is only available in extended mode.
ee2d5c50 22769
8e04817f 22770The @samp{R} packet has no reply.
ee2d5c50 22771
b8ff78ce
JB
22772@item s @var{addr}
22773@cindex @samp{s} packet
22774Single step. @var{addr} is the address at which to resume. If
22775@var{addr} is omitted, resume at same address.
c906108c 22776
ee2d5c50
AC
22777Reply:
22778@xref{Stop Reply Packets}, for the reply specifications.
22779
b8ff78ce 22780@item S @var{sig};@var{addr}
ee2d5c50 22781@anchor{step with signal packet}
b8ff78ce
JB
22782@cindex @samp{S} packet
22783Step with signal. This is analogous to the @samp{C} packet, but
22784requests a single-step, rather than a normal resumption of execution.
c906108c 22785
ee2d5c50
AC
22786Reply:
22787@xref{Stop Reply Packets}, for the reply specifications.
22788
b8ff78ce
JB
22789@item t @var{addr}:@var{PP},@var{MM}
22790@cindex @samp{t} packet
8e04817f 22791Search backwards starting at address @var{addr} for a match with pattern
ee2d5c50
AC
22792@var{PP} and mask @var{MM}. @var{PP} and @var{MM} are 4 bytes.
22793@var{addr} must be at least 3 digits.
c906108c 22794
b8ff78ce
JB
22795@item T @var{XX}
22796@cindex @samp{T} packet
ee2d5c50 22797Find out if the thread XX is alive.
c906108c 22798
ee2d5c50
AC
22799Reply:
22800@table @samp
22801@item OK
22802thread is still alive
b8ff78ce 22803@item E @var{NN}
ee2d5c50
AC
22804thread is dead
22805@end table
22806
b8ff78ce
JB
22807@item v
22808Packets starting with @samp{v} are identified by a multi-letter name,
22809up to the first @samp{;} or @samp{?} (or the end of the packet).
86d30acc 22810
b8ff78ce
JB
22811@item vCont@r{[};@var{action}@r{[}:@var{tid}@r{]]}@dots{}
22812@cindex @samp{vCont} packet
22813Resume the inferior, specifying different actions for each thread.
86d30acc
DJ
22814If an action is specified with no @var{tid}, then it is applied to any
22815threads that don't have a specific action specified; if no default action is
22816specified then other threads should remain stopped. Specifying multiple
22817default actions is an error; specifying no actions is also an error.
22818Thread IDs are specified in hexadecimal. Currently supported actions are:
22819
b8ff78ce 22820@table @samp
86d30acc
DJ
22821@item c
22822Continue.
b8ff78ce 22823@item C @var{sig}
86d30acc
DJ
22824Continue with signal @var{sig}. @var{sig} should be two hex digits.
22825@item s
22826Step.
b8ff78ce 22827@item S @var{sig}
86d30acc
DJ
22828Step with signal @var{sig}. @var{sig} should be two hex digits.
22829@end table
22830
22831The optional @var{addr} argument normally associated with these packets is
b8ff78ce 22832not supported in @samp{vCont}.
86d30acc
DJ
22833
22834Reply:
22835@xref{Stop Reply Packets}, for the reply specifications.
22836
b8ff78ce
JB
22837@item vCont?
22838@cindex @samp{vCont?} packet
22839Request a list of actions supporetd by the @samp{vCont} packet.
86d30acc
DJ
22840
22841Reply:
22842@table @samp
b8ff78ce
JB
22843@item vCont@r{[};@var{action}@dots{}@r{]}
22844The @samp{vCont} packet is supported. Each @var{action} is a supported
22845command in the @samp{vCont} packet.
86d30acc 22846@item
b8ff78ce 22847The @samp{vCont} packet is not supported.
86d30acc 22848@end table
ee2d5c50 22849
b8ff78ce 22850@item X @var{addr},@var{length}:@var{XX@dots{}}
9a6253be 22851@anchor{X packet}
b8ff78ce
JB
22852@cindex @samp{X} packet
22853Write data to memory, where the data is transmitted in binary.
22854@var{addr} is address, @var{length} is number of bytes,
22855@samp{@var{XX}@dots{}} is binary data. The bytes @code{0x23}
22856(@sc{ascii} @samp{#}), @code{0x24} (@sc{ascii} @samp{$}), and
22857@code{0x7d} (@sc{ascii} @samp{@}}) are escaped using @code{0x7d}
22858(@sc{ascii} @samp{@}}), and then XORed with @code{0x20}. For example,
22859the byte @code{0x7d} would be transmitted as the two bytes @code{0x7d
228600x5d}.
c906108c 22861
ee2d5c50
AC
22862Reply:
22863@table @samp
22864@item OK
22865for success
b8ff78ce 22866@item E @var{NN}
ee2d5c50
AC
22867for an error
22868@end table
22869
b8ff78ce
JB
22870@item z @var{type},@var{addr},@var{length}
22871@itemx Z @var{type},@var{addr},@var{length}
2f870471 22872@anchor{insert breakpoint or watchpoint packet}
b8ff78ce
JB
22873@cindex @samp{z} packet
22874@cindex @samp{Z} packets
22875Insert (@samp{Z}) or remove (@samp{z}) a @var{type} breakpoint or
2f870471
AC
22876watchpoint starting at address @var{address} and covering the next
22877@var{length} bytes.
ee2d5c50 22878
2f870471
AC
22879Each breakpoint and watchpoint packet @var{type} is documented
22880separately.
22881
512217c7
AC
22882@emph{Implementation notes: A remote target shall return an empty string
22883for an unrecognized breakpoint or watchpoint packet @var{type}. A
22884remote target shall support either both or neither of a given
b8ff78ce 22885@samp{Z@var{type}@dots{}} and @samp{z@var{type}@dots{}} packet pair. To
2f870471
AC
22886avoid potential problems with duplicate packets, the operations should
22887be implemented in an idempotent way.}
22888
b8ff78ce
JB
22889@item z0,@var{addr},@var{length}
22890@itemx Z0,@var{addr},@var{length}
22891@cindex @samp{z0} packet
22892@cindex @samp{Z0} packet
22893Insert (@samp{Z0}) or remove (@samp{z0}) a memory breakpoint at address
22894@var{addr} of size @var{length}.
2f870471
AC
22895
22896A memory breakpoint is implemented by replacing the instruction at
22897@var{addr} with a software breakpoint or trap instruction. The
b8ff78ce 22898@var{length} is used by targets that indicates the size of the
2f870471
AC
22899breakpoint (in bytes) that should be inserted (e.g., the @sc{arm} and
22900@sc{mips} can insert either a 2 or 4 byte breakpoint).
c906108c 22901
2f870471
AC
22902@emph{Implementation note: It is possible for a target to copy or move
22903code that contains memory breakpoints (e.g., when implementing
22904overlays). The behavior of this packet, in the presence of such a
22905target, is not defined.}
c906108c 22906
ee2d5c50
AC
22907Reply:
22908@table @samp
2f870471
AC
22909@item OK
22910success
22911@item
22912not supported
b8ff78ce 22913@item E @var{NN}
ee2d5c50 22914for an error
2f870471
AC
22915@end table
22916
b8ff78ce
JB
22917@item z1,@var{addr},@var{length}
22918@itemx Z1,@var{addr},@var{length}
22919@cindex @samp{z1} packet
22920@cindex @samp{Z1} packet
22921Insert (@samp{Z1}) or remove (@samp{z1}) a hardware breakpoint at
22922address @var{addr} of size @var{length}.
2f870471
AC
22923
22924A hardware breakpoint is implemented using a mechanism that is not
22925dependant on being able to modify the target's memory.
22926
22927@emph{Implementation note: A hardware breakpoint is not affected by code
22928movement.}
22929
22930Reply:
22931@table @samp
ee2d5c50 22932@item OK
2f870471
AC
22933success
22934@item
22935not supported
b8ff78ce 22936@item E @var{NN}
2f870471
AC
22937for an error
22938@end table
22939
b8ff78ce
JB
22940@item z2,@var{addr},@var{length}
22941@itemx Z2,@var{addr},@var{length}
22942@cindex @samp{z2} packet
22943@cindex @samp{Z2} packet
22944Insert (@samp{Z2}) or remove (@samp{z2}) a write watchpoint.
2f870471
AC
22945
22946Reply:
22947@table @samp
22948@item OK
22949success
22950@item
22951not supported
b8ff78ce 22952@item E @var{NN}
2f870471
AC
22953for an error
22954@end table
22955
b8ff78ce
JB
22956@item z3,@var{addr},@var{length}
22957@itemx Z3,@var{addr},@var{length}
22958@cindex @samp{z3} packet
22959@cindex @samp{Z3} packet
22960Insert (@samp{Z3}) or remove (@samp{z3}) a read watchpoint.
2f870471
AC
22961
22962Reply:
22963@table @samp
22964@item OK
22965success
22966@item
22967not supported
b8ff78ce 22968@item E @var{NN}
2f870471
AC
22969for an error
22970@end table
22971
b8ff78ce
JB
22972@item z4,@var{addr},@var{length}
22973@itemx Z4,@var{addr},@var{length}
22974@cindex @samp{z4} packet
22975@cindex @samp{Z4} packet
22976Insert (@samp{Z4}) or remove (@samp{z4}) an access watchpoint.
2f870471
AC
22977
22978Reply:
22979@table @samp
22980@item OK
22981success
22982@item
22983not supported
b8ff78ce 22984@item E @var{NN}
2f870471 22985for an error
ee2d5c50
AC
22986@end table
22987
22988@end table
c906108c 22989
ee2d5c50
AC
22990@node Stop Reply Packets
22991@section Stop Reply Packets
22992@cindex stop reply packets
c906108c 22993
8e04817f
AC
22994The @samp{C}, @samp{c}, @samp{S}, @samp{s} and @samp{?} packets can
22995receive any of the below as a reply. In the case of the @samp{C},
22996@samp{c}, @samp{S} and @samp{s} packets, that reply is only returned
b8ff78ce
JB
22997when the target halts. In the below the exact meaning of @dfn{signal
22998number} is poorly defined. In general one of the UNIX signal
22999numbering conventions is used.
c906108c 23000
b8ff78ce
JB
23001As in the description of request packets, we include spaces in the
23002reply templates for clarity; these are not part of the reply packet's
23003syntax. No @value{GDBN} stop reply packet uses spaces to separate its
23004components.
c906108c 23005
b8ff78ce 23006@table @samp
ee2d5c50 23007
b8ff78ce
JB
23008@item S @var{AA}
23009The program received signal number @var{AA} (a two-digit hexidecimal
23010number).
c906108c 23011
b8ff78ce
JB
23012@item T @var{AA} @var{n1}:@var{r1};@var{n2}:@var{r2};@dots{}
23013@cindex @samp{T} packet reply
23014The program received signal number @var{AA} (a two-digit hexidecimal
23015number). Single-step and breakpoint traps are reported this way. The
23016@samp{@var{n}:@var{r}} pairs give the values of important registers or
23017other information:
23018@enumerate
23019@item
23020If @var{n} is a hexidecimal number, it is a register number, and the
23021corresponding @var{r} gives that register's value. @var{r} is a
23022series of bytes in target byte order, with each byte given by a
23023two-digit hex number.
23024@item
23025If @var{n} is @samp{thread}, then @var{r} is the thread process ID, in
23026hex.
23027@item
23028If @var{n} is @samp{watch}, @samp{rwatch}, or @samp{awatch}, then the
23029packet indicates a watchpoint hit, and @var{r} is the data address, in
23030hex.
23031@item
23032Otherwise, @value{GDBN} should ignore this @samp{@var{n}:@var{r}} pair
23033and go on to the next; this allows us to extend the protocol in the
23034future.
23035@end enumerate
ee2d5c50 23036
b8ff78ce 23037@item W @var{AA}
8e04817f 23038The process exited, and @var{AA} is the exit status. This is only
ee2d5c50
AC
23039applicable to certain targets.
23040
b8ff78ce 23041@item X @var{AA}
8e04817f 23042The process terminated with signal @var{AA}.
c906108c 23043
b8ff78ce
JB
23044@item O @var{XX}@dots{}
23045@samp{@var{XX}@dots{}} is hex encoding of @sc{ascii} data, to be
23046written as the program's console output. This can happen at any time
23047while the program is running and the debugger should continue to wait
23048for @samp{W}, @samp{T}, etc.
0ce1b118 23049
b8ff78ce 23050@item F @var{call-id},@var{parameter}@dots{}
0ce1b118
CV
23051@var{call-id} is the identifier which says which host system call should
23052be called. This is just the name of the function. Translation into the
23053correct system call is only applicable as it's defined in @value{GDBN}.
23054@xref{File-I/O remote protocol extension}, for a list of implemented
23055system calls.
23056
b8ff78ce
JB
23057@samp{@var{parameter}@dots{}} is a list of parameters as defined for
23058this very system call.
0ce1b118 23059
b8ff78ce
JB
23060The target replies with this packet when it expects @value{GDBN} to
23061call a host system call on behalf of the target. @value{GDBN} replies
23062with an appropriate @samp{F} packet and keeps up waiting for the next
23063reply packet from the target. The latest @samp{C}, @samp{c}, @samp{S}
23064or @samp{s} action is expected to be continued. @xref{File-I/O remote
23065protocol extension}, for more details.
0ce1b118 23066
ee2d5c50
AC
23067@end table
23068
23069@node General Query Packets
23070@section General Query Packets
9c16f35a 23071@cindex remote query requests
c906108c 23072
5f3bebba
JB
23073Packets starting with @samp{q} are @dfn{general query packets};
23074packets starting with @samp{Q} are @dfn{general set packets}. General
23075query and set packets are a semi-unified form for retrieving and
23076sending information to and from the stub.
23077
23078The initial letter of a query or set packet is followed by a name
23079indicating what sort of thing the packet applies to. For example,
23080@value{GDBN} may use a @samp{qSymbol} packet to exchange symbol
23081definitions with the stub. These packet names follow some
23082conventions:
23083
23084@itemize @bullet
23085@item
23086The name must not contain commas, colons or semicolons.
23087@item
23088Most @value{GDBN} query and set packets have a leading upper case
23089letter.
23090@item
23091The names of custom vendor packets should use a company prefix, in
23092lower case, followed by a period. For example, packets designed at
23093the Acme Corporation might begin with @samp{qacme.foo} (for querying
23094foos) or @samp{Qacme.bar} (for setting bars).
23095@end itemize
23096
23097A query or set packet may optionally be followed by a @samp{,} or
23098@samp{;} separated list. Stubs must be careful to match the full
23099packet name, in case packet names have common prefixes.
c906108c 23100
b8ff78ce
JB
23101Like the descriptions of the other packets, each description here
23102has a template showing the packet's overall syntax, followed by an
23103explanation of the packet's meaning. We include spaces in some of the
23104templates for clarity; these are not part of the packet's syntax. No
23105@value{GDBN} packet uses spaces to separate its components.
23106
5f3bebba
JB
23107Here are the currently defined query and set packets:
23108
b8ff78ce 23109@table @samp
c906108c 23110
b8ff78ce 23111@item qC
9c16f35a 23112@cindex current thread, remote request
b8ff78ce 23113@cindex @samp{qC} packet
ee2d5c50
AC
23114Return the current thread id.
23115
23116Reply:
23117@table @samp
b8ff78ce 23118@item QC @var{pid}
e1aac25b 23119Where @var{pid} is an unsigned hexidecimal process id.
b8ff78ce 23120@item @r{(anything else)}
ee2d5c50
AC
23121Any other reply implies the old pid.
23122@end table
23123
b8ff78ce 23124@item qCRC:@var{addr},@var{length}
ff2587ec 23125@cindex CRC of memory block, remote request
b8ff78ce
JB
23126@cindex @samp{qCRC} packet
23127Compute the CRC checksum of a block of memory.
ff2587ec
WZ
23128Reply:
23129@table @samp
b8ff78ce 23130@item E @var{NN}
ff2587ec 23131An error (such as memory fault)
b8ff78ce
JB
23132@item C @var{crc32}
23133The specified memory region's checksum is @var{crc32}.
ff2587ec
WZ
23134@end table
23135
b8ff78ce
JB
23136@item qfThreadInfo
23137@itemx qsThreadInfo
9c16f35a 23138@cindex list active threads, remote request
b8ff78ce
JB
23139@cindex @samp{qfThreadInfo} packet
23140@cindex @samp{qsThreadInfo} packet
23141Obtain a list of all active thread ids from the target (OS). Since there
8e04817f
AC
23142may be too many active threads to fit into one reply packet, this query
23143works iteratively: it may require more than one query/reply sequence to
23144obtain the entire list of threads. The first query of the sequence will
b8ff78ce
JB
23145be the @samp{qfThreadInfo} query; subsequent queries in the
23146sequence will be the @samp{qsThreadInfo} query.
ee2d5c50 23147
b8ff78ce 23148NOTE: This packet replaces the @samp{qL} query (see below).
ee2d5c50
AC
23149
23150Reply:
23151@table @samp
b8ff78ce 23152@item m @var{id}
ee2d5c50 23153A single thread id
b8ff78ce 23154@item m @var{id},@var{id}@dots{}
ee2d5c50 23155a comma-separated list of thread ids
b8ff78ce
JB
23156@item l
23157(lower case letter @samp{L}) denotes end of list.
ee2d5c50
AC
23158@end table
23159
23160In response to each query, the target will reply with a list of one or
e1aac25b
JB
23161more thread ids, in big-endian unsigned hex, separated by commas.
23162@value{GDBN} will respond to each reply with a request for more thread
b8ff78ce
JB
23163ids (using the @samp{qs} form of the query), until the target responds
23164with @samp{l} (lower-case el, for @dfn{last}).
c906108c 23165
b8ff78ce 23166@item qGetTLSAddr:@var{thread-id},@var{offset},@var{lm}
ff2587ec 23167@cindex get thread-local storage address, remote request
b8ff78ce 23168@cindex @samp{qGetTLSAddr} packet
ff2587ec
WZ
23169Fetch the address associated with thread local storage specified
23170by @var{thread-id}, @var{offset}, and @var{lm}.
23171
23172@var{thread-id} is the (big endian, hex encoded) thread id associated with the
23173thread for which to fetch the TLS address.
23174
23175@var{offset} is the (big endian, hex encoded) offset associated with the
23176thread local variable. (This offset is obtained from the debug
23177information associated with the variable.)
23178
23179@var{lm} is the (big endian, hex encoded) OS/ABI specific encoding of the
23180the load module associated with the thread local storage. For example,
23181a @sc{gnu}/Linux system will pass the link map address of the shared
23182object associated with the thread local storage under consideration.
23183Other operating environments may choose to represent the load module
23184differently, so the precise meaning of this parameter will vary.
ee2d5c50
AC
23185
23186Reply:
b8ff78ce
JB
23187@table @samp
23188@item @var{XX}@dots{}
ff2587ec
WZ
23189Hex encoded (big endian) bytes representing the address of the thread
23190local storage requested.
23191
b8ff78ce
JB
23192@item E @var{nn}
23193An error occurred. @var{nn} are hex digits.
ff2587ec 23194
b8ff78ce
JB
23195@item
23196An empty reply indicates that @samp{qGetTLSAddr} is not supported by the stub.
ee2d5c50
AC
23197@end table
23198
ff2587ec
WZ
23199Use of this request packet is controlled by the @code{set remote
23200get-thread-local-storage-address} command (@pxref{Remote
23201configuration, set remote get-thread-local-storage-address}).
23202
b8ff78ce 23203@item qL @var{startflag} @var{threadcount} @var{nextthread}
8e04817f
AC
23204Obtain thread information from RTOS. Where: @var{startflag} (one hex
23205digit) is one to indicate the first query and zero to indicate a
23206subsequent query; @var{threadcount} (two hex digits) is the maximum
23207number of threads the response packet can contain; and @var{nextthread}
23208(eight hex digits), for subsequent queries (@var{startflag} is zero), is
23209returned in the response as @var{argthread}.
ee2d5c50 23210
b8ff78ce 23211Don't use this packet; use the @samp{qfThreadInfo} query instead (see above).
ee2d5c50
AC
23212
23213Reply:
23214@table @samp
b8ff78ce 23215@item qM @var{count} @var{done} @var{argthread} @var{thread}@dots{}
8e04817f
AC
23216Where: @var{count} (two hex digits) is the number of threads being
23217returned; @var{done} (one hex digit) is zero to indicate more threads
23218and one indicates no further threads; @var{argthreadid} (eight hex
b8ff78ce 23219digits) is @var{nextthread} from the request packet; @var{thread}@dots{}
ee2d5c50 23220is a sequence of thread IDs from the target. @var{threadid} (eight hex
8e04817f 23221digits). See @code{remote.c:parse_threadlist_response()}.
ee2d5c50 23222@end table
c906108c 23223
b8ff78ce 23224@item qOffsets
9c16f35a 23225@cindex section offsets, remote request
b8ff78ce 23226@cindex @samp{qOffsets} packet
8e04817f
AC
23227Get section offsets that the target used when re-locating the downloaded
23228image. @emph{Note: while a @code{Bss} offset is included in the
23229response, @value{GDBN} ignores this and instead applies the @code{Data}
23230offset to the @code{Bss} section.}
c906108c 23231
ee2d5c50
AC
23232Reply:
23233@table @samp
b8ff78ce 23234@item Text=@var{xxx};Data=@var{yyy};Bss=@var{zzz}
ee2d5c50
AC
23235@end table
23236
b8ff78ce 23237@item qP @var{mode} @var{threadid}
9c16f35a 23238@cindex thread information, remote request
b8ff78ce 23239@cindex @samp{qP} packet
8e04817f
AC
23240Returns information on @var{threadid}. Where: @var{mode} is a hex
23241encoded 32 bit mode; @var{threadid} is a hex encoded 64 bit thread ID.
ee2d5c50 23242
b8ff78ce 23243Reply: see @code{remote.c:remote_unpack_thread_info_response()}.
c906108c 23244
b8ff78ce 23245@item qPart:@var{object}:read:@var{annex}:@var{offset},@var{length}
9c16f35a 23246@cindex read special object, remote request
b8ff78ce 23247@cindex @samp{qPart} packet
649e03f6 23248Read uninterpreted bytes from the target's special data area
b8ff78ce
JB
23249identified by the keyword @var{object}. Request @var{length} bytes
23250starting at @var{offset} bytes into the data. The content and
23251encoding of @var{annex} is specific to the object; it can supply
23252additional details about what data to access.
649e03f6 23253
b8ff78ce
JB
23254Here are the specific requests of this form defined so far. All
23255@samp{qPart:@var{object}:read:@dots{}} requests use the same reply
23256formats, listed below.
649e03f6 23257
b8ff78ce
JB
23258@table @samp
23259@item qPart:auxv:read::@var{offset},@var{length}
721c2651
EZ
23260Access the target's @dfn{auxiliary vector}. @xref{OS Information,
23261auxiliary vector}, and see @ref{Remote configuration,
23262read-aux-vector-packet}. Note @var{annex} must be empty.
649e03f6
RM
23263@end table
23264
23265Reply:
b8ff78ce
JB
23266@table @samp
23267@item OK
649e03f6
RM
23268The @var{offset} in the request is at the end of the data.
23269There is no more data to be read.
23270
b8ff78ce 23271@item @var{XX}@dots{}
649e03f6
RM
23272Hex encoded data bytes read.
23273This may be fewer bytes than the @var{length} in the request.
23274
b8ff78ce 23275@item E00
649e03f6
RM
23276The request was malformed, or @var{annex} was invalid.
23277
b8ff78ce 23278@item E @var{nn}
649e03f6
RM
23279The offset was invalid, or there was an error encountered reading the data.
23280@var{nn} is a hex-encoded @code{errno} value.
23281
b8ff78ce 23282@item
649e03f6
RM
23283An empty reply indicates the @var{object} or @var{annex} string was not
23284recognized by the stub.
23285@end table
23286
b8ff78ce 23287@item qPart:@var{object}:write:@var{annex}:@var{offset}:@var{data}@dots{}
9c16f35a 23288@cindex write data into object, remote request
649e03f6 23289Write uninterpreted bytes into the target's special data area
b8ff78ce
JB
23290identified by the keyword @var{object}, starting at @var{offset} bytes
23291into the data. @samp{@var{data}@dots{}} is the hex-encoded data to be
23292written. The content and encoding of @var{annex} is specific to the
23293object; it can supply additional details about what data to access.
649e03f6
RM
23294
23295No requests of this form are presently in use. This specification
23296serves as a placeholder to document the common format that new
23297specific request specifications ought to use.
23298
23299Reply:
b8ff78ce 23300@table @samp
649e03f6
RM
23301@item @var{nn}
23302@var{nn} (hex encoded) is the number of bytes written.
23303This may be fewer bytes than supplied in the request.
23304
b8ff78ce 23305@item E00
649e03f6
RM
23306The request was malformed, or @var{annex} was invalid.
23307
b8ff78ce 23308@item E @var{nn}
649e03f6
RM
23309The offset was invalid, or there was an error encountered writing the data.
23310@var{nn} is a hex-encoded @code{errno} value.
23311
b8ff78ce 23312@item
649e03f6
RM
23313An empty reply indicates the @var{object} or @var{annex} string was not
23314recognized by the stub, or that the object does not support writing.
23315@end table
23316
b8ff78ce 23317@item qPart:@var{object}:@var{operation}:@dots{}
649e03f6
RM
23318Requests of this form may be added in the future. When a stub does
23319not recognize the @var{object} keyword, or its support for
b8ff78ce
JB
23320@var{object} does not recognize the @var{operation} keyword, the stub
23321must respond with an empty packet.
83761cbd 23322
b8ff78ce 23323@item qRcmd,@var{command}
ff2587ec 23324@cindex execute remote command, remote request
b8ff78ce 23325@cindex @samp{qRcmd} packet
ff2587ec 23326@var{command} (hex encoded) is passed to the local interpreter for
b8ff78ce
JB
23327execution. Invalid commands should be reported using the output
23328string. Before the final result packet, the target may also respond
23329with a number of intermediate @samp{O@var{output}} console output
23330packets. @emph{Implementors should note that providing access to a
23331stubs's interpreter may have security implications}.
fa93a9d8 23332
ff2587ec
WZ
23333Reply:
23334@table @samp
23335@item OK
23336A command response with no output.
23337@item @var{OUTPUT}
23338A command response with the hex encoded output string @var{OUTPUT}.
b8ff78ce 23339@item E @var{NN}
ff2587ec 23340Indicate a badly formed request.
b8ff78ce
JB
23341@item
23342An empty reply indicates that @samp{qRcmd} is not recognized.
ff2587ec 23343@end table
fa93a9d8 23344
b8ff78ce 23345@item qSymbol::
ff2587ec 23346@cindex symbol lookup, remote request
b8ff78ce 23347@cindex @samp{qSymbol} packet
ff2587ec
WZ
23348Notify the target that @value{GDBN} is prepared to serve symbol lookup
23349requests. Accept requests from the target for the values of symbols.
fa93a9d8
JB
23350
23351Reply:
ff2587ec 23352@table @samp
b8ff78ce 23353@item OK
ff2587ec 23354The target does not need to look up any (more) symbols.
b8ff78ce 23355@item qSymbol:@var{sym_name}
ff2587ec
WZ
23356The target requests the value of symbol @var{sym_name} (hex encoded).
23357@value{GDBN} may provide the value by using the
b8ff78ce
JB
23358@samp{qSymbol:@var{sym_value}:@var{sym_name}} message, described
23359below.
ff2587ec 23360@end table
83761cbd 23361
b8ff78ce 23362@item qSymbol:@var{sym_value}:@var{sym_name}
ff2587ec
WZ
23363Set the value of @var{sym_name} to @var{sym_value}.
23364
23365@var{sym_name} (hex encoded) is the name of a symbol whose value the
23366target has previously requested.
23367
23368@var{sym_value} (hex) is the value for symbol @var{sym_name}. If
23369@value{GDBN} cannot supply a value for @var{sym_name}, then this field
23370will be empty.
23371
23372Reply:
23373@table @samp
b8ff78ce 23374@item OK
ff2587ec 23375The target does not need to look up any (more) symbols.
b8ff78ce 23376@item qSymbol:@var{sym_name}
ff2587ec
WZ
23377The target requests the value of a new symbol @var{sym_name} (hex
23378encoded). @value{GDBN} will continue to supply the values of symbols
23379(if available), until the target ceases to request them.
fa93a9d8 23380@end table
0abb7bc7 23381
9d29849a
JB
23382@item QTDP
23383@itemx QTFrame
23384@xref{Tracepoint Packets}.
23385
b8ff78ce 23386@item qThreadExtraInfo,@var{id}
ff2587ec 23387@cindex thread attributes info, remote request
b8ff78ce
JB
23388@cindex @samp{qThreadExtraInfo} packet
23389Obtain a printable string description of a thread's attributes from
23390the target OS. @var{id} is a thread-id in big-endian hex. This
23391string may contain anything that the target OS thinks is interesting
23392for @value{GDBN} to tell the user about the thread. The string is
23393displayed in @value{GDBN}'s @code{info threads} display. Some
23394examples of possible thread extra info strings are @samp{Runnable}, or
23395@samp{Blocked on Mutex}.
ff2587ec
WZ
23396
23397Reply:
23398@table @samp
b8ff78ce
JB
23399@item @var{XX}@dots{}
23400Where @samp{@var{XX}@dots{}} is a hex encoding of @sc{ascii} data,
23401comprising the printable string containing the extra information about
23402the thread's attributes.
ff2587ec 23403@end table
814e32d7 23404
9d29849a
JB
23405@item QTStart
23406@itemx QTStop
23407@itemx QTinit
23408@itemx QTro
23409@itemx qTStatus
23410@xref{Tracepoint Packets}.
23411
ee2d5c50
AC
23412@end table
23413
23414@node Register Packet Format
23415@section Register Packet Format
eb12ee30 23416
b8ff78ce 23417The following @code{g}/@code{G} packets have previously been defined.
ee2d5c50
AC
23418In the below, some thirty-two bit registers are transferred as
23419sixty-four bits. Those registers should be zero/sign extended (which?)
23420to fill the space allocated. Register bytes are transfered in target
23421byte order. The two nibbles within a register byte are transfered
23422most-significant - least-significant.
eb12ee30 23423
ee2d5c50 23424@table @r
eb12ee30 23425
8e04817f 23426@item MIPS32
ee2d5c50 23427
8e04817f
AC
23428All registers are transfered as thirty-two bit quantities in the order:
2342932 general-purpose; sr; lo; hi; bad; cause; pc; 32 floating-point
23430registers; fsr; fir; fp.
eb12ee30 23431
8e04817f 23432@item MIPS64
ee2d5c50 23433
8e04817f
AC
23434All registers are transfered as sixty-four bit quantities (including
23435thirty-two bit registers such as @code{sr}). The ordering is the same
23436as @code{MIPS32}.
eb12ee30 23437
ee2d5c50
AC
23438@end table
23439
9d29849a
JB
23440@node Tracepoint Packets
23441@section Tracepoint Packets
23442@cindex tracepoint packets
23443@cindex packets, tracepoint
23444
23445Here we describe the packets @value{GDBN} uses to implement
23446tracepoints (@pxref{Tracepoints}).
23447
23448@table @samp
23449
23450@item QTDP:@var{n}:@var{addr}:@var{ena}:@var{step}:@var{pass}@r{[}-@r{]}
23451Create a new tracepoint, number @var{n}, at @var{addr}. If @var{ena}
23452is @samp{E}, then the tracepoint is enabled; if it is @samp{D}, then
23453the tracepoint is disabled. @var{step} is the tracepoint's step
23454count, and @var{pass} is its pass count. If the trailing @samp{-} is
23455present, further @samp{QTDP} packets will follow to specify this
23456tracepoint's actions.
23457
23458Replies:
23459@table @samp
23460@item OK
23461The packet was understood and carried out.
23462@item
23463The packet was not recognized.
23464@end table
23465
23466@item QTDP:-@var{n}:@var{addr}:@r{[}S@r{]}@var{action}@dots{}@r{[}-@r{]}
23467Define actions to be taken when a tracepoint is hit. @var{n} and
23468@var{addr} must be the same as in the initial @samp{QTDP} packet for
23469this tracepoint. This packet may only be sent immediately after
23470another @samp{QTDP} packet that ended with a @samp{-}. If the
23471trailing @samp{-} is present, further @samp{QTDP} packets will follow,
23472specifying more actions for this tracepoint.
23473
23474In the series of action packets for a given tracepoint, at most one
23475can have an @samp{S} before its first @var{action}. If such a packet
23476is sent, it and the following packets define ``while-stepping''
23477actions. Any prior packets define ordinary actions --- that is, those
23478taken when the tracepoint is first hit. If no action packet has an
23479@samp{S}, then all the packets in the series specify ordinary
23480tracepoint actions.
23481
23482The @samp{@var{action}@dots{}} portion of the packet is a series of
23483actions, concatenated without separators. Each action has one of the
23484following forms:
23485
23486@table @samp
23487
23488@item R @var{mask}
23489Collect the registers whose bits are set in @var{mask}. @var{mask} is
23490a hexidecimal number whose @var{i}'th bit is set if register number
23491@var{i} should be collected. (The least significant bit is numbered
23492zero.) Note that @var{mask} may be any number of digits long; it may
23493not fit in a 32-bit word.
23494
23495@item M @var{basereg},@var{offset},@var{len}
23496Collect @var{len} bytes of memory starting at the address in register
23497number @var{basereg}, plus @var{offset}. If @var{basereg} is
23498@samp{-1}, then the range has a fixed address: @var{offset} is the
23499address of the lowest byte to collect. The @var{basereg},
23500@var{offset}, and @var{len} parameters are all unsigned hexidecimal
23501values (the @samp{-1} value for @var{basereg} is a special case).
23502
23503@item X @var{len},@var{expr}
23504Evaluate @var{expr}, whose length is @var{len}, and collect memory as
23505it directs. @var{expr} is an agent expression, as described in
23506@ref{Agent Expressions}. Each byte of the expression is encoded as a
23507two-digit hex number in the packet; @var{len} is the number of bytes
23508in the expression (and thus one-half the number of hex digits in the
23509packet).
23510
23511@end table
23512
23513Any number of actions may be packed together in a single @samp{QTDP}
23514packet, as long as the packet does not exceed the maximum packet
c1947b85
JB
23515length (400 bytes, for many stubs). There may be only one @samp{R}
23516action per tracepoint, and it must precede any @samp{M} or @samp{X}
23517actions. Any registers referred to by @samp{M} and @samp{X} actions
23518must be collected by a preceding @samp{R} action. (The
23519``while-stepping'' actions are treated as if they were attached to a
23520separate tracepoint, as far as these restrictions are concerned.)
9d29849a
JB
23521
23522Replies:
23523@table @samp
23524@item OK
23525The packet was understood and carried out.
23526@item
23527The packet was not recognized.
23528@end table
23529
23530@item QTFrame:@var{n}
23531Select the @var{n}'th tracepoint frame from the buffer, and use the
23532register and memory contents recorded there to answer subsequent
23533request packets from @value{GDBN}.
23534
23535A successful reply from the stub indicates that the stub has found the
23536requested frame. The response is a series of parts, concatenated
23537without separators, describing the frame we selected. Each part has
23538one of the following forms:
23539
23540@table @samp
23541@item F @var{f}
23542The selected frame is number @var{n} in the trace frame buffer;
23543@var{f} is a hexidecimal number. If @var{f} is @samp{-1}, then there
23544was no frame matching the criteria in the request packet.
23545
23546@item T @var{t}
23547The selected trace frame records a hit of tracepoint number @var{t};
23548@var{t} is a hexidecimal number.
23549
23550@end table
23551
23552@item QTFrame:pc:@var{addr}
23553Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the
23554currently selected frame whose PC is @var{addr};
23555@var{addr} is a hexidecimal number.
23556
23557@item QTFrame:tdp:@var{t}
23558Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the
23559currently selected frame that is a hit of tracepoint @var{t}; @var{t}
23560is a hexidecimal number.
23561
23562@item QTFrame:range:@var{start}:@var{end}
23563Like @samp{QTFrame:@var{n}}, but select the first tracepoint frame after the
23564currently selected frame whose PC is between @var{start} (inclusive)
23565and @var{end} (exclusive); @var{start} and @var{end} are hexidecimal
23566numbers.
23567
23568@item QTFrame:outside:@var{start}:@var{end}
23569Like @samp{QTFrame:range:@var{start}:@var{end}}, but select the first
23570frame @emph{outside} the given range of addresses.
23571
23572@item QTStart
23573Begin the tracepoint experiment. Begin collecting data from tracepoint
23574hits in the trace frame buffer.
23575
23576@item QTStop
23577End the tracepoint experiment. Stop collecting trace frames.
23578
23579@item QTinit
23580Clear the table of tracepoints, and empty the trace frame buffer.
23581
23582@item QTro:@var{start1},@var{end1}:@var{start2},@var{end2}:@dots{}
23583Establish the given ranges of memory as ``transparent''. The stub
23584will answer requests for these ranges from memory's current contents,
23585if they were not collected as part of the tracepoint hit.
23586
23587@value{GDBN} uses this to mark read-only regions of memory, like those
23588containing program code. Since these areas never change, they should
23589still have the same contents they did when the tracepoint was hit, so
23590there's no reason for the stub to refuse to provide their contents.
23591
23592@item qTStatus
23593Ask the stub if there is a trace experiment running right now.
23594
23595Replies:
23596@table @samp
23597@item T0
23598There is no trace experiment running.
23599@item T1
23600There is a trace experiment running.
23601@end table
23602
23603@end table
23604
23605
9a6253be
KB
23606@node Interrupts
23607@section Interrupts
23608@cindex interrupts (remote protocol)
23609
23610When a program on the remote target is running, @value{GDBN} may
23611attempt to interrupt it by sending a @samp{Ctrl-C} or a @code{BREAK},
23612control of which is specified via @value{GDBN}'s @samp{remotebreak}
23613setting (@pxref{set remotebreak}).
23614
23615The precise meaning of @code{BREAK} is defined by the transport
23616mechanism and may, in fact, be undefined. @value{GDBN} does
23617not currently define a @code{BREAK} mechanism for any of the network
23618interfaces.
23619
23620@samp{Ctrl-C}, on the other hand, is defined and implemented for all
23621transport mechanisms. It is represented by sending the single byte
23622@code{0x03} without any of the usual packet overhead described in
23623the Overview section (@pxref{Overview}). When a @code{0x03} byte is
23624transmitted as part of a packet, it is considered to be packet data
23625and does @emph{not} represent an interrupt. E.g., an @samp{X} packet
23626(@pxref{X packet}, used for binary downloads, may include an unescaped
23627@code{0x03} as part of its packet.
23628
23629Stubs are not required to recognize these interrupt mechanisms and the
23630precise meaning associated with receipt of the interrupt is
23631implementation defined. If the stub is successful at interrupting the
23632running program, it is expected that it will send one of the Stop
23633Reply Packets (@pxref{Stop Reply Packets}) to @value{GDBN} as a result
23634of successfully stopping the program. Interrupts received while the
23635program is stopped will be discarded.
23636
ee2d5c50
AC
23637@node Examples
23638@section Examples
eb12ee30 23639
8e04817f
AC
23640Example sequence of a target being re-started. Notice how the restart
23641does not get any direct output:
eb12ee30 23642
474c8240 23643@smallexample
d2c6833e
AC
23644-> @code{R00}
23645<- @code{+}
8e04817f 23646@emph{target restarts}
d2c6833e 23647-> @code{?}
8e04817f 23648<- @code{+}
d2c6833e
AC
23649<- @code{T001:1234123412341234}
23650-> @code{+}
474c8240 23651@end smallexample
eb12ee30 23652
8e04817f 23653Example sequence of a target being stepped by a single instruction:
eb12ee30 23654
474c8240 23655@smallexample
d2c6833e 23656-> @code{G1445@dots{}}
8e04817f 23657<- @code{+}
d2c6833e
AC
23658-> @code{s}
23659<- @code{+}
23660@emph{time passes}
23661<- @code{T001:1234123412341234}
8e04817f 23662-> @code{+}
d2c6833e 23663-> @code{g}
8e04817f 23664<- @code{+}
d2c6833e
AC
23665<- @code{1455@dots{}}
23666-> @code{+}
474c8240 23667@end smallexample
eb12ee30 23668
0ce1b118
CV
23669@node File-I/O remote protocol extension
23670@section File-I/O remote protocol extension
23671@cindex File-I/O remote protocol extension
23672
23673@menu
23674* File-I/O Overview::
23675* Protocol basics::
1d8b2f28
JB
23676* The F request packet::
23677* The F reply packet::
0ce1b118
CV
23678* Memory transfer::
23679* The Ctrl-C message::
23680* Console I/O::
23681* The isatty call::
23682* The system call::
23683* List of supported calls::
23684* Protocol specific representation of datatypes::
23685* Constants::
23686* File-I/O Examples::
23687@end menu
23688
23689@node File-I/O Overview
23690@subsection File-I/O Overview
23691@cindex file-i/o overview
23692
9c16f35a
EZ
23693The @dfn{File I/O remote protocol extension} (short: File-I/O) allows the
23694target to use the host's file system and console I/O when calling various
0ce1b118
CV
23695system calls. System calls on the target system are translated into a
23696remote protocol packet to the host system which then performs the needed
23697actions and returns with an adequate response packet to the target system.
23698This simulates file system operations even on targets that lack file systems.
23699
23700The protocol is defined host- and target-system independent. It uses
9c16f35a 23701its own independent representation of datatypes and values. Both,
0ce1b118
CV
23702@value{GDBN} and the target's @value{GDBN} stub are responsible for
23703translating the system dependent values into the unified protocol values
23704when data is transmitted.
23705
23706The communication is synchronous. A system call is possible only
23707when GDB is waiting for the @samp{C}, @samp{c}, @samp{S} or @samp{s}
23708packets. While @value{GDBN} handles the request for a system call,
23709the target is stopped to allow deterministic access to the target's
23710memory. Therefore File-I/O is not interuptible by target signals. It
23711is possible to interrupt File-I/O by a user interrupt (Ctrl-C), though.
23712
23713The target's request to perform a host system call does not finish
23714the latest @samp{C}, @samp{c}, @samp{S} or @samp{s} action. That means,
23715after finishing the system call, the target returns to continuing the
23716previous activity (continue, step). No additional continue or step
23717request from @value{GDBN} is required.
23718
23719@smallexample
f7dc1244 23720(@value{GDBP}) continue
0ce1b118
CV
23721 <- target requests 'system call X'
23722 target is stopped, @value{GDBN} executes system call
23723 -> GDB returns result
23724 ... target continues, GDB returns to wait for the target
23725 <- target hits breakpoint and sends a Txx packet
23726@end smallexample
23727
23728The protocol is only used for files on the host file system and
23729for I/O on the console. Character or block special devices, pipes,
23730named pipes or sockets or any other communication method on the host
23731system are not supported by this protocol.
23732
23733@node Protocol basics
23734@subsection Protocol basics
23735@cindex protocol basics, file-i/o
23736
23737The File-I/O protocol uses the @code{F} packet, as request as well
23738as as reply packet. Since a File-I/O system call can only occur when
b383017d 23739@value{GDBN} is waiting for the continuing or stepping target, the
0ce1b118
CV
23740File-I/O request is a reply that @value{GDBN} has to expect as a result
23741of a former @samp{C}, @samp{c}, @samp{S} or @samp{s} packet.
23742This @code{F} packet contains all information needed to allow @value{GDBN}
23743to call the appropriate host system call:
23744
23745@itemize @bullet
b383017d 23746@item
0ce1b118
CV
23747A unique identifier for the requested system call.
23748
23749@item
23750All parameters to the system call. Pointers are given as addresses
23751in the target memory address space. Pointers to strings are given as
b383017d 23752pointer/length pair. Numerical values are given as they are.
0ce1b118
CV
23753Numerical control values are given in a protocol specific representation.
23754
23755@end itemize
23756
23757At that point @value{GDBN} has to perform the following actions.
23758
23759@itemize @bullet
b383017d 23760@item
0ce1b118
CV
23761If parameter pointer values are given, which point to data needed as input
23762to a system call, @value{GDBN} requests this data from the target with a
23763standard @code{m} packet request. This additional communication has to be
23764expected by the target implementation and is handled as any other @code{m}
23765packet.
23766
23767@item
23768@value{GDBN} translates all value from protocol representation to host
23769representation as needed. Datatypes are coerced into the host types.
23770
23771@item
23772@value{GDBN} calls the system call
23773
23774@item
23775It then coerces datatypes back to protocol representation.
23776
23777@item
23778If pointer parameters in the request packet point to buffer space in which
23779a system call is expected to copy data to, the data is transmitted to the
23780target using a @code{M} or @code{X} packet. This packet has to be expected
23781by the target implementation and is handled as any other @code{M} or @code{X}
23782packet.
23783
23784@end itemize
23785
23786Eventually @value{GDBN} replies with another @code{F} packet which contains all
23787necessary information for the target to continue. This at least contains
23788
23789@itemize @bullet
23790@item
23791Return value.
23792
23793@item
23794@code{errno}, if has been changed by the system call.
23795
23796@item
23797``Ctrl-C'' flag.
23798
23799@end itemize
23800
23801After having done the needed type and value coercion, the target continues
23802the latest continue or step action.
23803
1d8b2f28 23804@node The F request packet
0ce1b118
CV
23805@subsection The @code{F} request packet
23806@cindex file-i/o request packet
23807@cindex @code{F} request packet
23808
23809The @code{F} request packet has the following format:
23810
23811@table @samp
23812
23813@smallexample
23814@code{F}@var{call-id}@code{,}@var{parameter@dots{}}
23815@end smallexample
23816
23817@var{call-id} is the identifier to indicate the host system call to be called.
23818This is just the name of the function.
23819
23820@var{parameter@dots{}} are the parameters to the system call.
23821
b383017d 23822@end table
0ce1b118
CV
23823
23824Parameters are hexadecimal integer values, either the real values in case
23825of scalar datatypes, as pointers to target buffer space in case of compound
23826datatypes and unspecified memory areas or as pointer/length pairs in case
23827of string parameters. These are appended to the call-id, each separated
23828from its predecessor by a comma. All values are transmitted in ASCII
23829string representation, pointer/length pairs separated by a slash.
23830
1d8b2f28 23831@node The F reply packet
0ce1b118
CV
23832@subsection The @code{F} reply packet
23833@cindex file-i/o reply packet
23834@cindex @code{F} reply packet
23835
23836The @code{F} reply packet has the following format:
23837
23838@table @samp
23839
23840@smallexample
23841@code{F}@var{retcode}@code{,}@var{errno}@code{,}@var{Ctrl-C flag}@code{;}@var{call specific attachment}
23842@end smallexample
23843
23844@var{retcode} is the return code of the system call as hexadecimal value.
23845
23846@var{errno} is the errno set by the call, in protocol specific representation.
23847This parameter can be omitted if the call was successful.
23848
23849@var{Ctrl-C flag} is only send if the user requested a break. In this
23850case, @var{errno} must be send as well, even if the call was successful.
23851The @var{Ctrl-C flag} itself consists of the character 'C':
23852
23853@smallexample
23854F0,0,C
23855@end smallexample
23856
23857@noindent
23858or, if the call was interupted before the host call has been performed:
23859
23860@smallexample
23861F-1,4,C
23862@end smallexample
23863
23864@noindent
23865assuming 4 is the protocol specific representation of @code{EINTR}.
23866
23867@end table
23868
23869@node Memory transfer
23870@subsection Memory transfer
23871@cindex memory transfer, in file-i/o protocol
23872
23873Structured data which is transferred using a memory read or write as e.g.@:
23874a @code{struct stat} is expected to be in a protocol specific format with
23875all scalar multibyte datatypes being big endian. This should be done by
23876the target before the @code{F} packet is sent resp.@: by @value{GDBN} before
23877it transfers memory to the target. Transferred pointers to structured
23878data should point to the already coerced data at any time.
23879
23880@node The Ctrl-C message
23881@subsection The Ctrl-C message
23882@cindex ctrl-c message, in file-i/o protocol
23883
23884A special case is, if the @var{Ctrl-C flag} is set in the @value{GDBN}
23885reply packet. In this case the target should behave, as if it had
23886gotten a break message. The meaning for the target is ``system call
23887interupted by @code{SIGINT}''. Consequentially, the target should actually stop
23888(as with a break message) and return to @value{GDBN} with a @code{T02}
b383017d 23889packet. In this case, it's important for the target to know, in which
0ce1b118
CV
23890state the system call was interrupted. Since this action is by design
23891not an atomic operation, we have to differ between two cases:
23892
23893@itemize @bullet
23894@item
23895The system call hasn't been performed on the host yet.
23896
23897@item
23898The system call on the host has been finished.
23899
23900@end itemize
23901
23902These two states can be distinguished by the target by the value of the
23903returned @code{errno}. If it's the protocol representation of @code{EINTR}, the system
23904call hasn't been performed. This is equivalent to the @code{EINTR} handling
23905on POSIX systems. In any other case, the target may presume that the
23906system call has been finished --- successful or not --- and should behave
23907as if the break message arrived right after the system call.
23908
23909@value{GDBN} must behave reliable. If the system call has not been called
23910yet, @value{GDBN} may send the @code{F} reply immediately, setting @code{EINTR} as
23911@code{errno} in the packet. If the system call on the host has been finished
23912before the user requests a break, the full action must be finshed by
23913@value{GDBN}. This requires sending @code{M} or @code{X} packets as they fit.
23914The @code{F} packet may only be send when either nothing has happened
23915or the full action has been completed.
23916
23917@node Console I/O
23918@subsection Console I/O
23919@cindex console i/o as part of file-i/o
23920
23921By default and if not explicitely closed by the target system, the file
23922descriptors 0, 1 and 2 are connected to the @value{GDBN} console. Output
23923on the @value{GDBN} console is handled as any other file output operation
23924(@code{write(1, @dots{})} or @code{write(2, @dots{})}). Console input is handled
23925by @value{GDBN} so that after the target read request from file descriptor
239260 all following typing is buffered until either one of the following
23927conditions is met:
23928
23929@itemize @bullet
23930@item
23931The user presses @kbd{Ctrl-C}. The behaviour is as explained above, the
23932@code{read}
23933system call is treated as finished.
23934
23935@item
23936The user presses @kbd{Enter}. This is treated as end of input with a trailing
23937line feed.
23938
23939@item
23940The user presses @kbd{Ctrl-D}. This is treated as end of input. No trailing
23941character, especially no Ctrl-D is appended to the input.
23942
23943@end itemize
23944
23945If the user has typed more characters as fit in the buffer given to
23946the read call, the trailing characters are buffered in @value{GDBN} until
23947either another @code{read(0, @dots{})} is requested by the target or debugging
23948is stopped on users request.
23949
23950@node The isatty call
2eecc4ab 23951@subsection The @samp{isatty} function call
0ce1b118
CV
23952@cindex isatty call, file-i/o protocol
23953
23954A special case in this protocol is the library call @code{isatty} which
9c16f35a 23955is implemented as its own call inside of this protocol. It returns
0ce1b118
CV
239561 to the target if the file descriptor given as parameter is attached
23957to the @value{GDBN} console, 0 otherwise. Implementing through system calls
23958would require implementing @code{ioctl} and would be more complex than
23959needed.
23960
23961@node The system call
2eecc4ab 23962@subsection The @samp{system} function call
0ce1b118
CV
23963@cindex system call, file-i/o protocol
23964
23965The other special case in this protocol is the @code{system} call which
9c16f35a 23966is implemented as its own call, too. @value{GDBN} is taking over the full
0ce1b118
CV
23967task of calling the necessary host calls to perform the @code{system}
23968call. The return value of @code{system} is simplified before it's returned
23969to the target. Basically, the only signal transmitted back is @code{EINTR}
23970in case the user pressed @kbd{Ctrl-C}. Otherwise the return value consists
23971entirely of the exit status of the called command.
23972
9c16f35a
EZ
23973Due to security concerns, the @code{system} call is by default refused
23974by @value{GDBN}. The user has to allow this call explicitly with the
23975@kbd{set remote system-call-allowed 1} command.
0ce1b118 23976
9c16f35a
EZ
23977@table @code
23978@item set remote system-call-allowed
23979@kindex set remote system-call-allowed
23980Control whether to allow the @code{system} calls in the File I/O
23981protocol for the remote target. The default is zero (disabled).
0ce1b118 23982
9c16f35a 23983@item show remote system-call-allowed
0ce1b118 23984@kindex show remote system-call-allowed
9c16f35a
EZ
23985Show the current setting of system calls for the remote File I/O
23986protocol.
0ce1b118
CV
23987@end table
23988
23989@node List of supported calls
23990@subsection List of supported calls
23991@cindex list of supported file-i/o calls
23992
23993@menu
23994* open::
23995* close::
23996* read::
23997* write::
23998* lseek::
23999* rename::
24000* unlink::
24001* stat/fstat::
24002* gettimeofday::
24003* isatty::
24004* system::
24005@end menu
24006
24007@node open
24008@unnumberedsubsubsec open
24009@cindex open, file-i/o system call
24010
24011@smallexample
24012@exdent Synopsis:
24013int open(const char *pathname, int flags);
24014int open(const char *pathname, int flags, mode_t mode);
24015
b383017d 24016@exdent Request:
0ce1b118
CV
24017Fopen,pathptr/len,flags,mode
24018@end smallexample
24019
24020@noindent
24021@code{flags} is the bitwise or of the following values:
24022
24023@table @code
b383017d 24024@item O_CREAT
0ce1b118
CV
24025If the file does not exist it will be created. The host
24026rules apply as far as file ownership and time stamps
24027are concerned.
24028
b383017d 24029@item O_EXCL
0ce1b118
CV
24030When used with O_CREAT, if the file already exists it is
24031an error and open() fails.
24032
b383017d 24033@item O_TRUNC
0ce1b118
CV
24034If the file already exists and the open mode allows
24035writing (O_RDWR or O_WRONLY is given) it will be
24036truncated to length 0.
24037
b383017d 24038@item O_APPEND
0ce1b118
CV
24039The file is opened in append mode.
24040
b383017d 24041@item O_RDONLY
0ce1b118
CV
24042The file is opened for reading only.
24043
b383017d 24044@item O_WRONLY
0ce1b118
CV
24045The file is opened for writing only.
24046
b383017d 24047@item O_RDWR
0ce1b118
CV
24048The file is opened for reading and writing.
24049
24050@noindent
24051Each other bit is silently ignored.
24052
24053@end table
24054
24055@noindent
24056@code{mode} is the bitwise or of the following values:
24057
24058@table @code
b383017d 24059@item S_IRUSR
0ce1b118
CV
24060User has read permission.
24061
b383017d 24062@item S_IWUSR
0ce1b118
CV
24063User has write permission.
24064
b383017d 24065@item S_IRGRP
0ce1b118
CV
24066Group has read permission.
24067
b383017d 24068@item S_IWGRP
0ce1b118
CV
24069Group has write permission.
24070
b383017d 24071@item S_IROTH
0ce1b118
CV
24072Others have read permission.
24073
b383017d 24074@item S_IWOTH
0ce1b118
CV
24075Others have write permission.
24076
24077@noindent
24078Each other bit is silently ignored.
24079
24080@end table
24081
24082@smallexample
24083@exdent Return value:
24084open returns the new file descriptor or -1 if an error
24085occured.
24086
24087@exdent Errors:
24088@end smallexample
24089
24090@table @code
b383017d 24091@item EEXIST
0ce1b118
CV
24092pathname already exists and O_CREAT and O_EXCL were used.
24093
b383017d 24094@item EISDIR
0ce1b118
CV
24095pathname refers to a directory.
24096
b383017d 24097@item EACCES
0ce1b118
CV
24098The requested access is not allowed.
24099
24100@item ENAMETOOLONG
24101pathname was too long.
24102
b383017d 24103@item ENOENT
0ce1b118
CV
24104A directory component in pathname does not exist.
24105
b383017d 24106@item ENODEV
0ce1b118
CV
24107pathname refers to a device, pipe, named pipe or socket.
24108
b383017d 24109@item EROFS
0ce1b118
CV
24110pathname refers to a file on a read-only filesystem and
24111write access was requested.
24112
b383017d 24113@item EFAULT
0ce1b118
CV
24114pathname is an invalid pointer value.
24115
b383017d 24116@item ENOSPC
0ce1b118
CV
24117No space on device to create the file.
24118
b383017d 24119@item EMFILE
0ce1b118
CV
24120The process already has the maximum number of files open.
24121
b383017d 24122@item ENFILE
0ce1b118
CV
24123The limit on the total number of files open on the system
24124has been reached.
24125
b383017d 24126@item EINTR
0ce1b118
CV
24127The call was interrupted by the user.
24128@end table
24129
24130@node close
24131@unnumberedsubsubsec close
24132@cindex close, file-i/o system call
24133
24134@smallexample
b383017d 24135@exdent Synopsis:
0ce1b118
CV
24136int close(int fd);
24137
b383017d 24138@exdent Request:
0ce1b118
CV
24139Fclose,fd
24140
24141@exdent Return value:
24142close returns zero on success, or -1 if an error occurred.
24143
24144@exdent Errors:
24145@end smallexample
24146
24147@table @code
b383017d 24148@item EBADF
0ce1b118
CV
24149fd isn't a valid open file descriptor.
24150
b383017d 24151@item EINTR
0ce1b118
CV
24152The call was interrupted by the user.
24153@end table
24154
24155@node read
24156@unnumberedsubsubsec read
24157@cindex read, file-i/o system call
24158
24159@smallexample
b383017d 24160@exdent Synopsis:
0ce1b118
CV
24161int read(int fd, void *buf, unsigned int count);
24162
b383017d 24163@exdent Request:
0ce1b118
CV
24164Fread,fd,bufptr,count
24165
24166@exdent Return value:
24167On success, the number of bytes read is returned.
24168Zero indicates end of file. If count is zero, read
b383017d 24169returns zero as well. On error, -1 is returned.
0ce1b118
CV
24170
24171@exdent Errors:
24172@end smallexample
24173
24174@table @code
b383017d 24175@item EBADF
0ce1b118
CV
24176fd is not a valid file descriptor or is not open for
24177reading.
24178
b383017d 24179@item EFAULT
0ce1b118
CV
24180buf is an invalid pointer value.
24181
b383017d 24182@item EINTR
0ce1b118
CV
24183The call was interrupted by the user.
24184@end table
24185
24186@node write
24187@unnumberedsubsubsec write
24188@cindex write, file-i/o system call
24189
24190@smallexample
b383017d 24191@exdent Synopsis:
0ce1b118
CV
24192int write(int fd, const void *buf, unsigned int count);
24193
b383017d 24194@exdent Request:
0ce1b118
CV
24195Fwrite,fd,bufptr,count
24196
24197@exdent Return value:
24198On success, the number of bytes written are returned.
24199Zero indicates nothing was written. On error, -1
24200is returned.
24201
24202@exdent Errors:
24203@end smallexample
24204
24205@table @code
b383017d 24206@item EBADF
0ce1b118
CV
24207fd is not a valid file descriptor or is not open for
24208writing.
24209
b383017d 24210@item EFAULT
0ce1b118
CV
24211buf is an invalid pointer value.
24212
b383017d 24213@item EFBIG
0ce1b118
CV
24214An attempt was made to write a file that exceeds the
24215host specific maximum file size allowed.
24216
b383017d 24217@item ENOSPC
0ce1b118
CV
24218No space on device to write the data.
24219
b383017d 24220@item EINTR
0ce1b118
CV
24221The call was interrupted by the user.
24222@end table
24223
24224@node lseek
24225@unnumberedsubsubsec lseek
24226@cindex lseek, file-i/o system call
24227
24228@smallexample
b383017d 24229@exdent Synopsis:
0ce1b118
CV
24230long lseek (int fd, long offset, int flag);
24231
b383017d 24232@exdent Request:
0ce1b118
CV
24233Flseek,fd,offset,flag
24234@end smallexample
24235
24236@code{flag} is one of:
24237
24238@table @code
b383017d 24239@item SEEK_SET
0ce1b118
CV
24240The offset is set to offset bytes.
24241
b383017d 24242@item SEEK_CUR
0ce1b118
CV
24243The offset is set to its current location plus offset
24244bytes.
24245
b383017d 24246@item SEEK_END
0ce1b118
CV
24247The offset is set to the size of the file plus offset
24248bytes.
24249@end table
24250
24251@smallexample
24252@exdent Return value:
24253On success, the resulting unsigned offset in bytes from
24254the beginning of the file is returned. Otherwise, a
24255value of -1 is returned.
24256
24257@exdent Errors:
24258@end smallexample
24259
24260@table @code
b383017d 24261@item EBADF
0ce1b118
CV
24262fd is not a valid open file descriptor.
24263
b383017d 24264@item ESPIPE
0ce1b118
CV
24265fd is associated with the @value{GDBN} console.
24266
b383017d 24267@item EINVAL
0ce1b118
CV
24268flag is not a proper value.
24269
b383017d 24270@item EINTR
0ce1b118
CV
24271The call was interrupted by the user.
24272@end table
24273
24274@node rename
24275@unnumberedsubsubsec rename
24276@cindex rename, file-i/o system call
24277
24278@smallexample
b383017d 24279@exdent Synopsis:
0ce1b118
CV
24280int rename(const char *oldpath, const char *newpath);
24281
b383017d 24282@exdent Request:
0ce1b118
CV
24283Frename,oldpathptr/len,newpathptr/len
24284
24285@exdent Return value:
24286On success, zero is returned. On error, -1 is returned.
24287
24288@exdent Errors:
24289@end smallexample
24290
24291@table @code
b383017d 24292@item EISDIR
0ce1b118
CV
24293newpath is an existing directory, but oldpath is not a
24294directory.
24295
b383017d 24296@item EEXIST
0ce1b118
CV
24297newpath is a non-empty directory.
24298
b383017d 24299@item EBUSY
0ce1b118
CV
24300oldpath or newpath is a directory that is in use by some
24301process.
24302
b383017d 24303@item EINVAL
0ce1b118
CV
24304An attempt was made to make a directory a subdirectory
24305of itself.
24306
b383017d 24307@item ENOTDIR
0ce1b118
CV
24308A component used as a directory in oldpath or new
24309path is not a directory. Or oldpath is a directory
24310and newpath exists but is not a directory.
24311
b383017d 24312@item EFAULT
0ce1b118
CV
24313oldpathptr or newpathptr are invalid pointer values.
24314
b383017d 24315@item EACCES
0ce1b118
CV
24316No access to the file or the path of the file.
24317
24318@item ENAMETOOLONG
b383017d 24319
0ce1b118
CV
24320oldpath or newpath was too long.
24321
b383017d 24322@item ENOENT
0ce1b118
CV
24323A directory component in oldpath or newpath does not exist.
24324
b383017d 24325@item EROFS
0ce1b118
CV
24326The file is on a read-only filesystem.
24327
b383017d 24328@item ENOSPC
0ce1b118
CV
24329The device containing the file has no room for the new
24330directory entry.
24331
b383017d 24332@item EINTR
0ce1b118
CV
24333The call was interrupted by the user.
24334@end table
24335
24336@node unlink
24337@unnumberedsubsubsec unlink
24338@cindex unlink, file-i/o system call
24339
24340@smallexample
b383017d 24341@exdent Synopsis:
0ce1b118
CV
24342int unlink(const char *pathname);
24343
b383017d 24344@exdent Request:
0ce1b118
CV
24345Funlink,pathnameptr/len
24346
24347@exdent Return value:
24348On success, zero is returned. On error, -1 is returned.
24349
24350@exdent Errors:
24351@end smallexample
24352
24353@table @code
b383017d 24354@item EACCES
0ce1b118
CV
24355No access to the file or the path of the file.
24356
b383017d 24357@item EPERM
0ce1b118
CV
24358The system does not allow unlinking of directories.
24359
b383017d 24360@item EBUSY
0ce1b118
CV
24361The file pathname cannot be unlinked because it's
24362being used by another process.
24363
b383017d 24364@item EFAULT
0ce1b118
CV
24365pathnameptr is an invalid pointer value.
24366
24367@item ENAMETOOLONG
24368pathname was too long.
24369
b383017d 24370@item ENOENT
0ce1b118
CV
24371A directory component in pathname does not exist.
24372
b383017d 24373@item ENOTDIR
0ce1b118
CV
24374A component of the path is not a directory.
24375
b383017d 24376@item EROFS
0ce1b118
CV
24377The file is on a read-only filesystem.
24378
b383017d 24379@item EINTR
0ce1b118
CV
24380The call was interrupted by the user.
24381@end table
24382
24383@node stat/fstat
24384@unnumberedsubsubsec stat/fstat
24385@cindex fstat, file-i/o system call
24386@cindex stat, file-i/o system call
24387
24388@smallexample
b383017d 24389@exdent Synopsis:
0ce1b118
CV
24390int stat(const char *pathname, struct stat *buf);
24391int fstat(int fd, struct stat *buf);
24392
b383017d 24393@exdent Request:
0ce1b118
CV
24394Fstat,pathnameptr/len,bufptr
24395Ffstat,fd,bufptr
24396
24397@exdent Return value:
24398On success, zero is returned. On error, -1 is returned.
24399
24400@exdent Errors:
24401@end smallexample
24402
24403@table @code
b383017d 24404@item EBADF
0ce1b118
CV
24405fd is not a valid open file.
24406
b383017d 24407@item ENOENT
0ce1b118
CV
24408A directory component in pathname does not exist or the
24409path is an empty string.
24410
b383017d 24411@item ENOTDIR
0ce1b118
CV
24412A component of the path is not a directory.
24413
b383017d 24414@item EFAULT
0ce1b118
CV
24415pathnameptr is an invalid pointer value.
24416
b383017d 24417@item EACCES
0ce1b118
CV
24418No access to the file or the path of the file.
24419
24420@item ENAMETOOLONG
24421pathname was too long.
24422
b383017d 24423@item EINTR
0ce1b118
CV
24424The call was interrupted by the user.
24425@end table
24426
24427@node gettimeofday
24428@unnumberedsubsubsec gettimeofday
24429@cindex gettimeofday, file-i/o system call
24430
24431@smallexample
b383017d 24432@exdent Synopsis:
0ce1b118
CV
24433int gettimeofday(struct timeval *tv, void *tz);
24434
b383017d 24435@exdent Request:
0ce1b118
CV
24436Fgettimeofday,tvptr,tzptr
24437
24438@exdent Return value:
24439On success, 0 is returned, -1 otherwise.
24440
24441@exdent Errors:
24442@end smallexample
24443
24444@table @code
b383017d 24445@item EINVAL
0ce1b118
CV
24446tz is a non-NULL pointer.
24447
b383017d 24448@item EFAULT
0ce1b118
CV
24449tvptr and/or tzptr is an invalid pointer value.
24450@end table
24451
24452@node isatty
24453@unnumberedsubsubsec isatty
24454@cindex isatty, file-i/o system call
24455
24456@smallexample
b383017d 24457@exdent Synopsis:
0ce1b118
CV
24458int isatty(int fd);
24459
b383017d 24460@exdent Request:
0ce1b118
CV
24461Fisatty,fd
24462
24463@exdent Return value:
24464Returns 1 if fd refers to the @value{GDBN} console, 0 otherwise.
24465
24466@exdent Errors:
24467@end smallexample
24468
24469@table @code
b383017d 24470@item EINTR
0ce1b118
CV
24471The call was interrupted by the user.
24472@end table
24473
24474@node system
24475@unnumberedsubsubsec system
24476@cindex system, file-i/o system call
24477
24478@smallexample
b383017d 24479@exdent Synopsis:
0ce1b118
CV
24480int system(const char *command);
24481
b383017d 24482@exdent Request:
0ce1b118
CV
24483Fsystem,commandptr/len
24484
24485@exdent Return value:
24486The value returned is -1 on error and the return status
24487of the command otherwise. Only the exit status of the
24488command is returned, which is extracted from the hosts
24489system return value by calling WEXITSTATUS(retval).
24490In case /bin/sh could not be executed, 127 is returned.
24491
24492@exdent Errors:
24493@end smallexample
24494
24495@table @code
b383017d 24496@item EINTR
0ce1b118
CV
24497The call was interrupted by the user.
24498@end table
24499
24500@node Protocol specific representation of datatypes
24501@subsection Protocol specific representation of datatypes
24502@cindex protocol specific representation of datatypes, in file-i/o protocol
24503
24504@menu
24505* Integral datatypes::
24506* Pointer values::
24507* struct stat::
24508* struct timeval::
24509@end menu
24510
24511@node Integral datatypes
24512@unnumberedsubsubsec Integral datatypes
24513@cindex integral datatypes, in file-i/o protocol
24514
24515The integral datatypes used in the system calls are
24516
24517@smallexample
24518int@r{,} unsigned int@r{,} long@r{,} unsigned long@r{,} mode_t @r{and} time_t
24519@end smallexample
24520
24521@code{Int}, @code{unsigned int}, @code{mode_t} and @code{time_t} are
24522implemented as 32 bit values in this protocol.
24523
b383017d
RM
24524@code{Long} and @code{unsigned long} are implemented as 64 bit types.
24525
0ce1b118
CV
24526@xref{Limits}, for corresponding MIN and MAX values (similar to those
24527in @file{limits.h}) to allow range checking on host and target.
24528
24529@code{time_t} datatypes are defined as seconds since the Epoch.
24530
24531All integral datatypes transferred as part of a memory read or write of a
24532structured datatype e.g.@: a @code{struct stat} have to be given in big endian
24533byte order.
24534
24535@node Pointer values
24536@unnumberedsubsubsec Pointer values
24537@cindex pointer values, in file-i/o protocol
24538
24539Pointers to target data are transmitted as they are. An exception
24540is made for pointers to buffers for which the length isn't
24541transmitted as part of the function call, namely strings. Strings
24542are transmitted as a pointer/length pair, both as hex values, e.g.@:
24543
24544@smallexample
24545@code{1aaf/12}
24546@end smallexample
24547
24548@noindent
24549which is a pointer to data of length 18 bytes at position 0x1aaf.
24550The length is defined as the full string length in bytes, including
24551the trailing null byte. Example:
24552
24553@smallexample
24554``hello, world'' at address 0x123456
24555@end smallexample
24556
24557@noindent
24558is transmitted as
24559
24560@smallexample
24561@code{123456/d}
24562@end smallexample
24563
24564@node struct stat
24565@unnumberedsubsubsec struct stat
24566@cindex struct stat, in file-i/o protocol
24567
24568The buffer of type struct stat used by the target and @value{GDBN} is defined
24569as follows:
24570
24571@smallexample
24572struct stat @{
24573 unsigned int st_dev; /* device */
24574 unsigned int st_ino; /* inode */
24575 mode_t st_mode; /* protection */
24576 unsigned int st_nlink; /* number of hard links */
24577 unsigned int st_uid; /* user ID of owner */
24578 unsigned int st_gid; /* group ID of owner */
24579 unsigned int st_rdev; /* device type (if inode device) */
24580 unsigned long st_size; /* total size, in bytes */
24581 unsigned long st_blksize; /* blocksize for filesystem I/O */
24582 unsigned long st_blocks; /* number of blocks allocated */
24583 time_t st_atime; /* time of last access */
24584 time_t st_mtime; /* time of last modification */
24585 time_t st_ctime; /* time of last change */
24586@};
24587@end smallexample
24588
24589The integral datatypes are conforming to the definitions given in the
24590approriate section (see @ref{Integral datatypes}, for details) so this
24591structure is of size 64 bytes.
24592
24593The values of several fields have a restricted meaning and/or
24594range of values.
24595
24596@smallexample
24597st_dev: 0 file
24598 1 console
24599
24600st_ino: No valid meaning for the target. Transmitted unchanged.
24601
24602st_mode: Valid mode bits are described in Appendix C. Any other
24603 bits have currently no meaning for the target.
24604
24605st_uid: No valid meaning for the target. Transmitted unchanged.
24606
24607st_gid: No valid meaning for the target. Transmitted unchanged.
24608
24609st_rdev: No valid meaning for the target. Transmitted unchanged.
24610
24611st_atime, st_mtime, st_ctime:
24612 These values have a host and file system dependent
24613 accuracy. Especially on Windows hosts the file systems
24614 don't support exact timing values.
24615@end smallexample
24616
24617The target gets a struct stat of the above representation and is
24618responsible to coerce it to the target representation before
24619continuing.
24620
24621Note that due to size differences between the host and target
24622representation of stat members, these members could eventually
24623get truncated on the target.
24624
24625@node struct timeval
24626@unnumberedsubsubsec struct timeval
24627@cindex struct timeval, in file-i/o protocol
24628
24629The buffer of type struct timeval used by the target and @value{GDBN}
24630is defined as follows:
24631
24632@smallexample
b383017d 24633struct timeval @{
0ce1b118
CV
24634 time_t tv_sec; /* second */
24635 long tv_usec; /* microsecond */
24636@};
24637@end smallexample
24638
24639The integral datatypes are conforming to the definitions given in the
24640approriate section (see @ref{Integral datatypes}, for details) so this
24641structure is of size 8 bytes.
24642
24643@node Constants
24644@subsection Constants
24645@cindex constants, in file-i/o protocol
24646
24647The following values are used for the constants inside of the
24648protocol. @value{GDBN} and target are resposible to translate these
24649values before and after the call as needed.
24650
24651@menu
24652* Open flags::
24653* mode_t values::
24654* Errno values::
24655* Lseek flags::
24656* Limits::
24657@end menu
24658
24659@node Open flags
24660@unnumberedsubsubsec Open flags
24661@cindex open flags, in file-i/o protocol
24662
24663All values are given in hexadecimal representation.
24664
24665@smallexample
24666 O_RDONLY 0x0
24667 O_WRONLY 0x1
24668 O_RDWR 0x2
24669 O_APPEND 0x8
24670 O_CREAT 0x200
24671 O_TRUNC 0x400
24672 O_EXCL 0x800
24673@end smallexample
24674
24675@node mode_t values
24676@unnumberedsubsubsec mode_t values
24677@cindex mode_t values, in file-i/o protocol
24678
24679All values are given in octal representation.
24680
24681@smallexample
24682 S_IFREG 0100000
24683 S_IFDIR 040000
24684 S_IRUSR 0400
24685 S_IWUSR 0200
24686 S_IXUSR 0100
24687 S_IRGRP 040
24688 S_IWGRP 020
24689 S_IXGRP 010
24690 S_IROTH 04
24691 S_IWOTH 02
24692 S_IXOTH 01
24693@end smallexample
24694
24695@node Errno values
24696@unnumberedsubsubsec Errno values
24697@cindex errno values, in file-i/o protocol
24698
24699All values are given in decimal representation.
24700
24701@smallexample
24702 EPERM 1
24703 ENOENT 2
24704 EINTR 4
24705 EBADF 9
24706 EACCES 13
24707 EFAULT 14
24708 EBUSY 16
24709 EEXIST 17
24710 ENODEV 19
24711 ENOTDIR 20
24712 EISDIR 21
24713 EINVAL 22
24714 ENFILE 23
24715 EMFILE 24
24716 EFBIG 27
24717 ENOSPC 28
24718 ESPIPE 29
24719 EROFS 30
24720 ENAMETOOLONG 91
24721 EUNKNOWN 9999
24722@end smallexample
24723
24724 EUNKNOWN is used as a fallback error value if a host system returns
24725 any error value not in the list of supported error numbers.
24726
24727@node Lseek flags
24728@unnumberedsubsubsec Lseek flags
24729@cindex lseek flags, in file-i/o protocol
24730
24731@smallexample
24732 SEEK_SET 0
24733 SEEK_CUR 1
24734 SEEK_END 2
24735@end smallexample
24736
24737@node Limits
24738@unnumberedsubsubsec Limits
24739@cindex limits, in file-i/o protocol
24740
24741All values are given in decimal representation.
24742
24743@smallexample
24744 INT_MIN -2147483648
24745 INT_MAX 2147483647
24746 UINT_MAX 4294967295
24747 LONG_MIN -9223372036854775808
24748 LONG_MAX 9223372036854775807
24749 ULONG_MAX 18446744073709551615
24750@end smallexample
24751
24752@node File-I/O Examples
24753@subsection File-I/O Examples
24754@cindex file-i/o examples
24755
24756Example sequence of a write call, file descriptor 3, buffer is at target
24757address 0x1234, 6 bytes should be written:
24758
24759@smallexample
24760<- @code{Fwrite,3,1234,6}
24761@emph{request memory read from target}
24762-> @code{m1234,6}
24763<- XXXXXX
24764@emph{return "6 bytes written"}
24765-> @code{F6}
24766@end smallexample
24767
24768Example sequence of a read call, file descriptor 3, buffer is at target
24769address 0x1234, 6 bytes should be read:
24770
24771@smallexample
24772<- @code{Fread,3,1234,6}
24773@emph{request memory write to target}
24774-> @code{X1234,6:XXXXXX}
24775@emph{return "6 bytes read"}
24776-> @code{F6}
24777@end smallexample
24778
24779Example sequence of a read call, call fails on the host due to invalid
24780file descriptor (EBADF):
24781
24782@smallexample
24783<- @code{Fread,3,1234,6}
24784-> @code{F-1,9}
24785@end smallexample
24786
24787Example sequence of a read call, user presses Ctrl-C before syscall on
24788host is called:
24789
24790@smallexample
24791<- @code{Fread,3,1234,6}
24792-> @code{F-1,4,C}
24793<- @code{T02}
24794@end smallexample
24795
24796Example sequence of a read call, user presses Ctrl-C after syscall on
24797host is called:
24798
24799@smallexample
24800<- @code{Fread,3,1234,6}
24801-> @code{X1234,6:XXXXXX}
24802<- @code{T02}
24803@end smallexample
24804
f418dd93
DJ
24805@include agentexpr.texi
24806
aab4e0ec 24807@include gpl.texi
eb12ee30 24808
2154891a 24809@raisesections
6826cf00 24810@include fdl.texi
2154891a 24811@lowersections
6826cf00 24812
6d2ebf8b 24813@node Index
c906108c
SS
24814@unnumbered Index
24815
24816@printindex cp
24817
24818@tex
24819% I think something like @colophon should be in texinfo. In the
24820% meantime:
24821\long\def\colophon{\hbox to0pt{}\vfill
24822\centerline{The body of this manual is set in}
24823\centerline{\fontname\tenrm,}
24824\centerline{with headings in {\bf\fontname\tenbf}}
24825\centerline{and examples in {\tt\fontname\tentt}.}
24826\centerline{{\it\fontname\tenit\/},}
24827\centerline{{\bf\fontname\tenbf}, and}
24828\centerline{{\sl\fontname\tensl\/}}
24829\centerline{are used for emphasis.}\vfill}
24830\page\colophon
24831% Blame: doc@cygnus.com, 1991.
24832@end tex
24833
c906108c 24834@bye
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