1 \input texinfo @c -*- Texinfo -*-
2 @setfilename binutils.info
8 * Binutils: (binutils). The GNU binary utilities "ar", "objcopy",
9 "objdump", "nm", "nlmconv", "size",
10 "strings", "strip", and "ranlib".
16 Copyright @copyright{} 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
18 Permission is granted to make and distribute verbatim copies of
19 this manual provided the copyright notice and this permission notice
20 are preserved on all copies.
23 Permission is granted to process this file through TeX and print the
24 results, provided the printed document carries a copying permission
25 notice identical to this one except for the removal of this paragraph
26 (this paragraph not being relevant to the printed manual).
30 Permission is granted to copy and distribute modified versions of this
31 manual under the conditions for verbatim copying, provided also that
32 the entire resulting derived work is distributed under the terms of a
33 permission notice identical to this one.
35 Permission is granted to copy and distribute translations of this manual
36 into another language, under the above conditions for modified versions.
41 @c This file documents the GNU binary utilities "ar", "ld", "objcopy",
42 @c "objdump", "nm", "size", "strings", "strip", and "ranlib".
44 @c Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
46 @c This text may be freely distributed under the terms of the GNU
47 @c General Public License.
50 @setchapternewpage odd
51 @settitle @sc{gnu} Binary Utilities
54 @title The @sc{gnu} Binary Utilities
55 @subtitle Version @value{VERSION}
58 @author Roland H. Pesch
59 @author Jeffrey M. Osier
60 @author Cygnus Support
64 {\parskip=0pt \hfill Cygnus Support\par \hfill
65 \TeX{}info \texinfoversion\par }
68 @vskip 0pt plus 1filll
69 Copyright @copyright{} 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
71 Permission is granted to make and distribute verbatim copies of
72 this manual provided the copyright notice and this permission notice
73 are preserved on all copies.
75 Permission is granted to copy and distribute modified versions of this
76 manual under the conditions for verbatim copying, provided also that
77 the entire resulting derived work is distributed under the terms of a
78 permission notice identical to this one.
80 Permission is granted to copy and distribute translations of this manual
81 into another language, under the above conditions for modified versions.
88 This brief manual contains preliminary documentation for the @sc{gnu} binary
89 utilities (collectively version @value{VERSION}):
94 Create, modify, and extract from archives
97 List symbols from object files
100 Copy and translate object files
103 Display information from object files
106 Generate index to archive contents
109 List file section sizes and total size
112 List printable strings from files
118 Demangle encoded C++ symbols
121 Convert object code into a Netware Loadable Module
126 * ar:: Create, modify, and extract from archives
127 * nm:: List symbols from object files
128 * objcopy:: Copy and translate object files
129 * objdump:: Display information from object files
130 * ranlib:: Generate index to archive contents
131 * size:: List section sizes and total size
132 * strings:: List printable strings from files
133 * strip:: Discard symbols
134 * c++filt:: Filter to demangle encoded C++ symbols
135 * nlmconv:: Converts object code into an NLM
136 * Selecting The Target System:: How these utilities determine the target.
145 @cindex collections of files
147 ar [-]@var{p}[@var{mod} [@var{relpos}]] @var{archive} [@var{member}@dots{}]
148 ar -M [ <mri-script ]
151 The @sc{gnu} @code{ar} program creates, modifies, and extracts from
152 archives. An @dfn{archive} is a single file holding a collection of
153 other files in a structure that makes it possible to retrieve
154 the original individual files (called @dfn{members} of the archive).
156 The original files' contents, mode (permissions), timestamp, owner, and
157 group are preserved in the archive, and can be restored on
161 @sc{gnu} @code{ar} can maintain archives whose members have names of any
162 length; however, depending on how @code{ar} is configured on your
163 system, a limit on member-name length may be imposed for compatibility
164 with archive formats maintained with other tools. If it exists, the
165 limit is often 15 characters (typical of formats related to a.out) or 16
166 characters (typical of formats related to coff).
169 @code{ar} is considered a binary utility because archives of this sort
170 are most often used as @dfn{libraries} holding commonly needed
174 @code{ar} creates an index to the symbols defined in relocatable
175 object modules in the archive when you specify the modifier @samp{s}.
176 Once created, this index is updated in the archive whenever @code{ar}
177 makes a change to its contents (save for the @samp{q} update operation).
178 An archive with such an index speeds up linking to the library, and
179 allows routines in the library to call each other without regard to
180 their placement in the archive.
182 You may use @samp{nm -s} or @samp{nm --print-armap} to list this index
183 table. If an archive lacks the table, another form of @code{ar} called
184 @code{ranlib} can be used to add just the table.
186 @cindex compatibility, @code{ar}
187 @cindex @code{ar} compatibility
188 @sc{gnu} @code{ar} is designed to be compatible with two different
189 facilities. You can control its activity using command-line options,
190 like the different varieties of @code{ar} on Unix systems; or, if you
191 specify the single command-line option @samp{-M}, you can control it
192 with a script supplied via standard input, like the MRI ``librarian''
196 * ar cmdline:: Controlling @code{ar} on the command line
197 * ar scripts:: Controlling @code{ar} with a script
202 @section Controlling @code{ar} on the command line
205 ar [-]@var{p}[@var{mod} [@var{relpos}]] @var{archive} [@var{member}@dots{}]
208 @cindex Unix compatibility, @code{ar}
209 When you use @code{ar} in the Unix style, @code{ar} insists on at least two
210 arguments to execute: one keyletter specifying the @emph{operation}
211 (optionally accompanied by other keyletters specifying
212 @emph{modifiers}), and the archive name to act on.
214 Most operations can also accept further @var{member} arguments,
215 specifying particular files to operate on.
217 @sc{gnu} @code{ar} allows you to mix the operation code @var{p} and modifier
218 flags @var{mod} in any order, within the first command-line argument.
220 If you wish, you may begin the first command-line argument with a
223 @cindex operations on archive
224 The @var{p} keyletter specifies what operation to execute; it may be
225 any of the following, but you must specify only one of them:
229 @cindex deleting from archive
230 @emph{Delete} modules from the archive. Specify the names of modules to
231 be deleted as @var{member}@dots{}; the archive is untouched if you
232 specify no files to delete.
234 If you specify the @samp{v} modifier, @code{ar} lists each module
238 @cindex moving in archive
239 Use this operation to @emph{move} members in an archive.
241 The ordering of members in an archive can make a difference in how
242 programs are linked using the library, if a symbol is defined in more
245 If no modifiers are used with @code{m}, any members you name in the
246 @var{member} arguments are moved to the @emph{end} of the archive;
247 you can use the @samp{a}, @samp{b}, or @samp{i} modifiers to move them to a
248 specified place instead.
251 @cindex printing from archive
252 @emph{Print} the specified members of the archive, to the standard
253 output file. If the @samp{v} modifier is specified, show the member
254 name before copying its contents to standard output.
256 If you specify no @var{member} arguments, all the files in the archive are
260 @cindex quick append to archive
261 @emph{Quick append}; add the files @var{member}@dots{} to the end of
262 @var{archive}, without checking for replacement.
264 The modifiers @samp{a}, @samp{b}, and @samp{i} do @emph{not} affect this
265 operation; new members are always placed at the end of the archive.
267 The modifier @samp{v} makes @code{ar} list each file as it is appended.
269 Since the point of this operation is speed, the archive's symbol table
270 index is not updated, even if it already existed; you can use @samp{ar s} or
271 @code{ranlib} explicitly to update the symbol table index.
274 @cindex replacement in archive
275 Insert the files @var{member}@dots{} into @var{archive} (with
276 @emph{replacement}). This operation differs from @samp{q} in that any
277 previously existing members are deleted if their names match those being
280 If one of the files named in @var{member}@dots{} does not exist, @code{ar}
281 displays an error message, and leaves undisturbed any existing members
282 of the archive matching that name.
284 By default, new members are added at the end of the file; but you may
285 use one of the modifiers @samp{a}, @samp{b}, or @samp{i} to request
286 placement relative to some existing member.
288 The modifier @samp{v} used with this operation elicits a line of
289 output for each file inserted, along with one of the letters @samp{a} or
290 @samp{r} to indicate whether the file was appended (no old member
291 deleted) or replaced.
294 @cindex contents of archive
295 Display a @emph{table} listing the contents of @var{archive}, or those
296 of the files listed in @var{member}@dots{} that are present in the
297 archive. Normally only the member name is shown; if you also want to
298 see the modes (permissions), timestamp, owner, group, and size, you can
299 request that by also specifying the @samp{v} modifier.
301 If you do not specify a @var{member}, all files in the archive
304 @cindex repeated names in archive
305 @cindex name duplication in archive
306 If there is more than one file with the same name (say, @samp{fie}) in
307 an archive (say @samp{b.a}), @samp{ar t b.a fie} lists only the
308 first instance; to see them all, you must ask for a complete
309 listing---in our example, @samp{ar t b.a}.
310 @c WRS only; per Gumby, this is implementation-dependent, and in a more
311 @c recent case in fact works the other way.
314 @cindex extract from archive
315 @emph{Extract} members (named @var{member}) from the archive. You can
316 use the @samp{v} modifier with this operation, to request that
317 @code{ar} list each name as it extracts it.
319 If you do not specify a @var{member}, all files in the archive
324 A number of modifiers (@var{mod}) may immediately follow the @var{p}
325 keyletter, to specify variations on an operation's behavior:
329 @cindex relative placement in archive
330 Add new files @emph{after} an existing member of the
331 archive. If you use the modifier @samp{a}, the name of an existing archive
332 member must be present as the @var{relpos} argument, before the
333 @var{archive} specification.
336 Add new files @emph{before} an existing member of the
337 archive. If you use the modifier @samp{b}, the name of an existing archive
338 member must be present as the @var{relpos} argument, before the
339 @var{archive} specification. (same as @samp{i}).
342 @cindex creating archives
343 @emph{Create} the archive. The specified @var{archive} is always
344 created if it did not exist, when you request an update. But a warning is
345 issued unless you specify in advance that you expect to create it, by
349 Truncate names in the archive. @sc{gnu} @code{ar} will normally permit file
350 names of any length. This will cause it to create archives which are
351 not compatible with the native @code{ar} program on some systems. If
352 this is a concern, the @samp{f} modifier may be used to truncate file
353 names when putting them in the archive.
356 Insert new files @emph{before} an existing member of the
357 archive. If you use the modifier @samp{i}, the name of an existing archive
358 member must be present as the @var{relpos} argument, before the
359 @var{archive} specification. (same as @samp{b}).
362 This modifier is accepted but not used.
363 @c whaffor ar l modifier??? presumably compat; with
364 @c what???---doc@@cygnus.com, 25jan91
367 @cindex dates in archive
368 Preserve the @emph{original} dates of members when extracting them. If
369 you do not specify this modifier, files extracted from the archive
370 are stamped with the time of extraction.
373 @cindex writing archive index
374 Write an object-file index into the archive, or update an existing one,
375 even if no other change is made to the archive. You may use this modifier
376 flag either with any operation, or alone. Running @samp{ar s} on an
377 archive is equivalent to running @samp{ranlib} on it.
380 @cindex updating an archive
381 Normally, @samp{ar r}@dots{} inserts all files
382 listed into the archive. If you would like to insert @emph{only} those
383 of the files you list that are newer than existing members of the same
384 names, use this modifier. The @samp{u} modifier is allowed only for the
385 operation @samp{r} (replace). In particular, the combination @samp{qu} is
386 not allowed, since checking the timestamps would lose any speed
387 advantage from the operation @samp{q}.
390 This modifier requests the @emph{verbose} version of an operation. Many
391 operations display additional information, such as filenames processed,
392 when the modifier @samp{v} is appended.
395 This modifier shows the version number of @code{ar}.
399 @section Controlling @code{ar} with a script
402 ar -M [ <@var{script} ]
405 @cindex MRI compatibility, @code{ar}
406 @cindex scripts, @code{ar}
407 If you use the single command-line option @samp{-M} with @code{ar}, you
408 can control its operation with a rudimentary command language. This
409 form of @code{ar} operates interactively if standard input is coming
410 directly from a terminal. During interactive use, @code{ar} prompts for
411 input (the prompt is @samp{AR >}), and continues executing even after
412 errors. If you redirect standard input to a script file, no prompts are
413 issued, and @code{ar} abandons execution (with a nonzero exit code)
416 The @code{ar} command language is @emph{not} designed to be equivalent
417 to the command-line options; in fact, it provides somewhat less control
418 over archives. The only purpose of the command language is to ease the
419 transition to @sc{gnu} @code{ar} for developers who already have scripts
420 written for the MRI ``librarian'' program.
422 The syntax for the @code{ar} command language is straightforward:
425 commands are recognized in upper or lower case; for example, @code{LIST}
426 is the same as @code{list}. In the following descriptions, commands are
427 shown in upper case for clarity.
430 a single command may appear on each line; it is the first word on the
434 empty lines are allowed, and have no effect.
437 comments are allowed; text after either of the characters @samp{*}
438 or @samp{;} is ignored.
441 Whenever you use a list of names as part of the argument to an @code{ar}
442 command, you can separate the individual names with either commas or
443 blanks. Commas are shown in the explanations below, for clarity.
446 @samp{+} is used as a line continuation character; if @samp{+} appears
447 at the end of a line, the text on the following line is considered part
448 of the current command.
451 Here are the commands you can use in @code{ar} scripts, or when using
452 @code{ar} interactively. Three of them have special significance:
454 @code{OPEN} or @code{CREATE} specify a @dfn{current archive}, which is
455 a temporary file required for most of the other commands.
457 @code{SAVE} commits the changes so far specified by the script. Prior
458 to @code{SAVE}, commands affect only the temporary copy of the current
462 @item ADDLIB @var{archive}
463 @itemx ADDLIB @var{archive} (@var{module}, @var{module}, @dots{} @var{module})
464 Add all the contents of @var{archive} (or, if specified, each named
465 @var{module} from @var{archive}) to the current archive.
467 Requires prior use of @code{OPEN} or @code{CREATE}.
469 @item ADDMOD @var{member}, @var{member}, @dots{} @var{member}
470 @c FIXME! w/Replacement?? If so, like "ar r @var{archive} @var{names}"
471 @c else like "ar q..."
472 Add each named @var{member} as a module in the current archive.
474 Requires prior use of @code{OPEN} or @code{CREATE}.
477 Discard the contents of the current archive, cancelling the effect of
478 any operations since the last @code{SAVE}. May be executed (with no
479 effect) even if no current archive is specified.
481 @item CREATE @var{archive}
482 Creates an archive, and makes it the current archive (required for many
483 other commands). The new archive is created with a temporary name; it
484 is not actually saved as @var{archive} until you use @code{SAVE}.
485 You can overwrite existing archives; similarly, the contents of any
486 existing file named @var{archive} will not be destroyed until @code{SAVE}.
488 @item DELETE @var{module}, @var{module}, @dots{} @var{module}
489 Delete each listed @var{module} from the current archive; equivalent to
490 @samp{ar -d @var{archive} @var{module} @dots{} @var{module}}.
492 Requires prior use of @code{OPEN} or @code{CREATE}.
494 @item DIRECTORY @var{archive} (@var{module}, @dots{} @var{module})
495 @itemx DIRECTORY @var{archive} (@var{module}, @dots{} @var{module}) @var{outputfile}
496 List each named @var{module} present in @var{archive}. The separate
497 command @code{VERBOSE} specifies the form of the output: when verbose
498 output is off, output is like that of @samp{ar -t @var{archive}
499 @var{module}@dots{}}. When verbose output is on, the listing is like
500 @samp{ar -tv @var{archive} @var{module}@dots{}}.
502 Output normally goes to the standard output stream; however, if you
503 specify @var{outputfile} as a final argument, @code{ar} directs the
507 Exit from @code{ar}, with a @code{0} exit code to indicate successful
508 completion. This command does not save the output file; if you have
509 changed the current archive since the last @code{SAVE} command, those
512 @item EXTRACT @var{module}, @var{module}, @dots{} @var{module}
513 Extract each named @var{module} from the current archive, writing them
514 into the current directory as separate files. Equivalent to @samp{ar -x
515 @var{archive} @var{module}@dots{}}.
517 Requires prior use of @code{OPEN} or @code{CREATE}.
520 @c FIXME Tokens but no commands???
527 Display full contents of the current archive, in ``verbose'' style
528 regardless of the state of @code{VERBOSE}. The effect is like @samp{ar
529 tv @var{archive}}). (This single command is a @sc{gnu} @code{ld}
530 enhancement, rather than present for MRI compatibility.)
532 Requires prior use of @code{OPEN} or @code{CREATE}.
534 @item OPEN @var{archive}
535 Opens an existing archive for use as the current archive (required for
536 many other commands). Any changes as the result of subsequent commands
537 will not actually affect @var{archive} until you next use @code{SAVE}.
539 @item REPLACE @var{module}, @var{module}, @dots{} @var{module}
540 In the current archive, replace each existing @var{module} (named in
541 the @code{REPLACE} arguments) from files in the current working directory.
542 To execute this command without errors, both the file, and the module in
543 the current archive, must exist.
545 Requires prior use of @code{OPEN} or @code{CREATE}.
548 Toggle an internal flag governing the output from @code{DIRECTORY}.
549 When the flag is on, @code{DIRECTORY} output matches output from
550 @samp{ar -tv }@dots{}.
553 Commit your changes to the current archive, and actually save it as a
554 file with the name specified in the last @code{CREATE} or @code{OPEN}
557 Requires prior use of @code{OPEN} or @code{CREATE}.
566 The @sc{gnu} linker @code{ld} is now described in a separate manual.
567 @xref{Top,, Overview,, Using LD: the @sc{gnu} linker}.
576 nm [ -a | --debug-syms ] [ -g | --extern-only ]
577 [ -B ] [ -C | --demangle ] [ -D | --dynamic ]
578 [ -s | --print-armap ] [ -A | -o | --print-file-name ]
579 [ -n | -v | --numeric-sort ] [ -p | --no-sort ]
580 [ -r | --reverse-sort ] [ --size-sort ] [ -u | --undefined-only ]
581 [ -t @var{radix} | --radix=@var{radix} ] [ -P | --portability ]
582 [ --target=@var{bfdname} ] [ -f @var{format} | --format=@var{format} ]
584 [ --no-demangle ] [ -V | --version ] [ --help ] [ @var{objfile}@dots{} ]
587 @sc{gnu} @code{nm} lists the symbols from object files @var{objfile}@dots{}.
588 If no object files are listed as arguments, @code{nm} assumes
591 For each symbol, @code{nm} shows:
595 The symbol value, in the radix selected by options (see below), or
596 hexadecimal by default.
599 The symbol type. At least the following types are used; others are, as
600 well, depending on the object file format. If lowercase, the symbol is
601 local; if uppercase, the symbol is global (external).
603 @c Some more detail on exactly what these symbol types are used for
610 BSS (uninitialized data).
632 The long and short forms of options, shown here as alternatives, are
638 @itemx --print-file-name
639 @cindex input file name
641 @cindex source file name
642 Precede each symbol by the name of the input file (or archive element)
643 in which it was found, rather than identifying the input file once only,
644 before all of its symbols.
648 @cindex debugging symbols
649 Display all symbols, even debugger-only symbols; normally these are not
653 @cindex @code{nm} format
654 @cindex @code{nm} compatibility
655 The same as @samp{--format=bsd} (for compatibility with the MIPS @code{nm}).
659 @cindex demangling C++ symbols
660 Decode (@dfn{demangle}) low-level symbol names into user-level names.
661 Besides removing any initial underscore prepended by the system, this
662 makes C++ function names readable. @xref{c++filt}, for more information
666 Do not demangle low-level symbol names. This is the default.
670 @cindex dynamic symbols
671 Display the dynamic symbols rather than the normal symbols. This is
672 only meaningful for dynamic objects, such as certain types of shared
675 @item -f @var{format}
676 @itemx --format=@var{format}
677 @cindex @code{nm} format
678 @cindex @code{nm} compatibility
679 Use the output format @var{format}, which can be @code{bsd},
680 @code{sysv}, or @code{posix}. The default is @code{bsd}.
681 Only the first character of @var{format} is significant; it can be
682 either upper or lower case.
686 @cindex external symbols
687 Display only external symbols.
691 @itemx --numeric-sort
692 Sort symbols numerically by their addresses, rather than alphabetically
697 @cindex sorting symbols
698 Do not bother to sort the symbols in any order; print them in the order
703 Use the POSIX.2 standard output format instead of the default format.
704 Equivalent to @samp{-f posix}.
708 @cindex symbol index, listing
709 When listing symbols from archive members, include the index: a mapping
710 (stored in the archive by @code{ar} or @code{ranlib}) of which modules
711 contain definitions for which names.
714 @itemx --reverse-sort
715 Reverse the order of the sort (whether numeric or alphabetic); let the
719 Sort symbols by size. The size is computed as the difference between
720 the value of the symbol and the value of the symbol with the next higher
721 value. The size of the symbol is printed, rather than the value.
724 @itemx --radix=@var{radix}
725 Use @var{radix} as the radix for printing the symbol values. It must be
726 @samp{d} for decimal, @samp{o} for octal, or @samp{x} for hexadecimal.
728 @item --target=@var{bfdname}
729 @cindex object code format
730 Specify an object code format other than your system's default format.
731 @xref{Target Selection}, for more information.
734 @itemx --undefined-only
735 @cindex external symbols
736 @cindex undefined symbols
737 Display only undefined symbols (those external to each object file).
740 @cindex external symbols
741 @cindex undefined symbols
742 Display only defined symbols for each object file.
746 Show the version number of @code{nm} and exit.
749 Show a summary of the options to @code{nm} and exit.
756 objcopy [ -F @var{bfdname} | --target=@var{bfdname} ]
757 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
758 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
759 [ -S | --strip-all ] [ -g | --strip-debug ]
760 [ -K @var{symbolname} | --keep-symbol=@var{symbolname} ]
761 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
762 [ -x | --discard-all ] [ -X | --discard-locals ]
763 [ -b @var{byte} | --byte=@var{byte} ]
764 [ -i @var{interleave} | --interleave=@var{interleave} ]
765 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
766 [ --gap-fill=@var{val} ] [ --pad-to=@var{address} ]
767 [ --set-start=@var{val} ] [ --adjust-start=@var{incr} ]
768 [ --adjust-vma=@var{incr} ]
769 [ --adjust-section-vma=@var{section}@{=,+,-@}@var{val} ]
770 [ --adjust-warnings ] [ --no-adjust-warnings ]
771 [ --set-section-flags=@var{section}=@var{flags} ]
772 [ --add-section=@var{sectionname}=@var{filename} ]
773 [ -v | --verbose ] [ -V | --version ] [ --help ]
774 @var{infile} [@var{outfile}]
777 The @sc{gnu} @code{objcopy} utility copies the contents of an object
778 file to another. @code{objcopy} uses the @sc{gnu} @sc{bfd} Library to
779 read and write the object files. It can write the destination object
780 file in a format different from that of the source object file. The
781 exact behavior of @code{objcopy} is controlled by command-line options.
783 @code{objcopy} creates temporary files to do its translations and
784 deletes them afterward. @code{objcopy} uses @sc{bfd} to do all its
785 translation work; it has access to all the formats described in @sc{bfd}
786 and thus is able to recognize most formats without being told
787 explicitly. @xref{BFD,,BFD,ld.info,Using LD}.
789 @code{objcopy} can be used to generate S-records by using an output
790 target of @samp{srec} (e.g., use @samp{-O srec}).
792 @code{objcopy} can be used to generate a raw binary file by using an
793 output target of @samp{binary} (e.g., use @samp{-O binary}). When
794 @code{objcopy} generates a raw binary file, it will essentially produce
795 a memory dump of the contents of the input object file. All symbols and
796 relocation information will be discarded. The memory dump will start at
797 the virtual address of the lowest section copied into the output file.
799 When generating an S-record or a raw binary file, it may be helpful to
800 use @samp{-S} to remove sections containing debugging information. In
801 some cases @samp{-R} will be useful to remove sections which contain
802 information which is not needed by the binary file.
807 The source and output files, respectively.
808 If you do not specify @var{outfile}, @code{objcopy} creates a
809 temporary file and destructively renames the result with
810 the name of @var{infile}.
812 @item -I @var{bfdname}
813 @itemx --input-target=@var{bfdname}
814 Consider the source file's object format to be @var{bfdname}, rather than
815 attempting to deduce it. @xref{Target Selection}, for more information.
817 @item -O @var{bfdname}
818 @itemx --output-target=@var{bfdname}
819 Write the output file using the object format @var{bfdname}.
820 @xref{Target Selection}, for more information.
822 @item -F @var{bfdname}
823 @itemx --target=@var{bfdname}
824 Use @var{bfdname} as the object format for both the input and the output
825 file; i.e., simply transfer data from source to destination with no
826 translation. @xref{Target Selection}, for more information.
828 @item -R @var{sectionname}
829 @itemx --remove-section=@var{sectionname}
830 Remove any section named @var{sectionname} from the output file. This
831 option may be given more than once. Note that using this option
832 inappropriately may make the output file unusable.
836 Do not copy relocation and symbol information from the source file.
840 Do not copy debugging symbols from the source file.
842 @item --strip-unneeded
843 Strip all symbols that are not needed for relocation processing.
845 @item -K @var{symbolname}
846 @itemx --keep-symbol=@var{symbolname}
847 Copy only symbol @var{symbolname} from the source file. This option may
848 be given more than once.
850 @item -N @var{symbolname}
851 @itemx --strip-symbol=@var{symbolname}
852 Do not copy symbol @var{symbolname} from the source file. This option
853 may be given more than once, and may be combined with strip options
854 other than @code{-K}.
858 Do not copy non-global symbols from the source file.
859 @c FIXME any reason to prefer "non-global" to "local" here?
862 @itemx --discard-locals
863 Do not copy compiler-generated local symbols.
864 (These usually start with @samp{L} or @samp{.}.)
867 @itemx --byte=@var{byte}
868 Keep only every @var{byte}th byte of the input file (header data is not
869 affected). @var{byte} can be in the range from 0 to @var{interleave}-1,
870 where @var{interleave} is given by the @samp{-i} or @samp{--interleave}
871 option, or the default of 4. This option is useful for creating files
872 to program @sc{rom}. It is typically used with an @code{srec} output
875 @item -i @var{interleave}
876 @itemx --interleave=@var{interleave}
877 Only copy one out of every @var{interleave} bytes. Select which byte to
878 copy with the @var{-b} or @samp{--byte} option. The default is 4.
879 @code{objcopy} ignores this option if you do not specify either @samp{-b} or
882 @item --gap-fill @var{val}
883 Fill gaps between sections with @var{val}. This is done by increasing
884 the size of the section with the lower address, and filling in the extra
885 space created with @var{val}.
887 @item --pad-to @var{address}
888 Pad the output file up to the virtual address @var{address}. This is
889 done by increasing the size of the last section. The extra space is
890 filled in with the value specified by @samp{--gap-fill} (default zero).
892 @item --set-start @var{val}
893 Set the address of the new file to @var{val}. Not all object file
894 formats support setting the start address.
896 @item --adjust-start @var{incr}
897 Adjust the start address by adding @var{incr}. Not all object file
898 formats support setting the start address.
900 @item --adjust-vma @var{incr}
901 Adjust the address of all sections, as well as the start address, by
902 adding @var{incr}. Some object file formats do not permit section
903 addresses to be changed arbitrarily. Note that this does not relocate
904 the sections; if the program expects sections to be loaded at a certain
905 address, and this option is used to change the sections such that they
906 are loaded at a different address, the program may fail.
908 @item --adjust-section-vma @var{section}@{=,+,-@}@var{val}
909 Set or adjust the address of the named @var{section}. If @samp{=} is
910 used, the section address is set to @var{val}. Otherwise, @var{val} is
911 added to or subtracted from the section address. See the comments under
912 @samp{--adjust-vma}, above. If @var{section} does not exist in the
913 input file, a warning will be issued, unless @samp{--no-adjust-warnings}
916 @item --adjust-warnings
917 If @samp{--adjust-section-vma} is used, and the named section does not
918 exist, issue a warning. This is the default.
920 @item --no-adjust-warnings
921 Do not issue a warning if @samp{--adjust-section-vma} is used, even if
922 the named section does not exist.
924 @item --set-section-flags @var{section}=@var{flags}
925 Set the flags for the named section. The @var{flags} argument is a
926 comma separated string of flag names. The recognized names are
927 @samp{alloc}, @samp{load}, @samp{readonly}, @samp{code}, @samp{data},
928 and @samp{rom}. Not all flags are meaningful for all object file
931 @item --add-section @var{sectionname}=@var{filename}
932 Add a new section named @var{sectionname} while copying the file. The
933 contents of the new section are taken from the file @var{filename}. The
934 size of the section will be the size of the file. This option only
935 works on file formats which can support sections with arbitrary names.
939 Show the version number of @code{objcopy}.
943 Verbose output: list all object files modified. In the case of
944 archives, @samp{objcopy -V} lists all members of the archive.
947 Show a summary of the options to @code{objcopy}.
953 @cindex object file information
957 objdump [ -a | --archive-headers ]
958 [ -b @var{bfdname} | --target=@var{bfdname} ] [ --debugging ]
959 [ -d | --disassemble ] [ -D | --disassemble-all ]
960 [ -f | --file-headers ]
961 [ -h | --section-headers | --headers ] [ -i | --info ]
962 [ -j @var{section} | --section=@var{section} ]
963 [ -l | --line-numbers ] [ -S | --source ]
964 [ -m @var{machine} | --architecture=@var{machine} ]
965 [ -r | --reloc ] [ -R | --dynamic-reloc ]
966 [ -s | --full-contents ] [ --stabs ]
967 [ -t | --syms ] [ -T | --dynamic-syms ] [ -x | --all-headers ]
968 [ -w | --wide ] [ --start-address=@var{address} ]
969 [ --stop-address=@var{address} ] [ --version ] [ --help ]
973 @code{objdump} displays information about one or more object files.
974 The options control what particular information to display. This
975 information is mostly useful to programmers who are working on the
976 compilation tools, as opposed to programmers who just want their
977 program to compile and work.
979 @var{objfile}@dots{} are the object files to be examined. When you
980 specify archives, @code{objdump} shows information on each of the member
983 The long and short forms of options, shown here as alternatives, are
984 equivalent. At least one option besides @samp{-l} must be given.
988 @itemx --archive-header
989 @cindex archive headers
990 If any of the @var{objfile} files are archives, display the archive
991 header information (in a format similar to @samp{ls -l}). Besides the
992 information you could list with @samp{ar tv}, @samp{objdump -a} shows
993 the object file format of each archive member.
995 @item -b @var{bfdname}
996 @itemx --target=@var{bfdname}
997 @cindex object code format
998 Specify that the object-code format for the object files is
999 @var{bfdname}. This option may not be necessary; @var{objdump} can
1000 automatically recognize many formats.
1004 objdump -b oasys -m vax -h fu.o
1007 displays summary information from the section headers (@samp{-h}) of
1008 @file{fu.o}, which is explicitly identified (@samp{-m}) as a VAX object
1009 file in the format produced by Oasys compilers. You can list the
1010 formats available with the @samp{-i} option.
1011 @xref{Target Selection}, for more information.
1014 Display debugging information. This attempts to parse debugging
1015 information stored in the file and print it out using a C like syntax.
1016 Only certain types of debugging information have been implemented.
1019 @itemx --disassemble
1020 @cindex disassembling object code
1021 @cindex machine instructions
1022 Display the assembler mnemonics for the machine instructions from
1023 @var{objfile}. This option only disassembles those sections which are
1024 expected to contain instructions.
1027 @itemx --disassemble-all
1028 Like @samp{-d}, but disassemble the contents of all sections, not just
1029 those expected to contain instructions.
1032 @itemx --file-header
1033 @cindex object file header
1034 Display summary information from the overall header of
1035 each of the @var{objfile} files.
1038 @itemx --section-header
1040 @cindex section headers
1041 Display summary information from the section headers of the
1044 File segments may be relocated to nonstandard addresses, for example by
1045 using the @samp{-Ttext}, @samp{-Tdata}, or @samp{-Tbss} options to
1046 @code{ld}. However, some object file formats, such as a.out, do not
1047 store the starting address of the file segments. In those situations,
1048 although @code{ld} relocates the sections correctly, using @samp{objdump
1049 -h} to list the file section headers cannot show the correct addresses.
1050 Instead, it shows the usual addresses, which are implicit for the
1054 Print a summary of the options to @code{objdump} and exit.
1058 @cindex architectures available
1059 @cindex object formats available
1060 Display a list showing all architectures and object formats available
1061 for specification with @samp{-b} or @samp{-m}.
1064 @itemx --section=@var{name}
1065 @cindex section information
1066 Display information only for section @var{name}.
1069 @itemx --line-numbers
1070 @cindex source filenames for object files
1071 Label the display (using debugging information) with the filename
1072 and source line numbers corresponding to the object code shown.
1073 Only useful with @samp{-d} or @samp{-D}.
1075 @item -m @var{machine}
1076 @itemx --architecture=@var{machine}
1077 @cindex architecture
1078 Specify that the object files @var{objfile} are for architecture
1079 @var{machine}. You can list available architectures using the @samp{-i}
1084 @cindex relocation entries, in object file
1085 Print the relocation entries of the file. If used with @samp{-d} or
1086 @samp{-D}, the relocations are printed interspersed with the
1090 @itemx --dynamic-reloc
1091 @cindex dynamic relocation entries, in object file
1092 Print the dynamic relocation entries of the file. This is only
1093 meaningful for dynamic objects, such as certain types of shared
1097 @itemx --full-contents
1098 @cindex sections, full contents
1099 @cindex object file sections
1100 Display the full contents of any sections requested.
1104 @cindex source disassembly
1105 @cindex disassembly, with source
1106 Display source code intermixed with disassembly, if possible. Implies
1112 @cindex debug symbols
1113 @cindex ELF object file format
1114 Display the full contents of any sections requested. Display the
1115 contents of the .stab and .stab.index and .stab.excl sections from an
1116 ELF file. This is only useful on systems (such as Solaris 2.0) in which
1117 @code{.stab} debugging symbol-table entries are carried in an ELF
1118 section. In most other file formats, debugging symbol-table entries are
1119 interleaved with linkage symbols, and are visible in the @samp{--syms}
1122 @item --start-address=@var{address}
1123 @cindex start-address
1124 Start displaying data at the specified address. This affects the output
1125 of the @code{-d}, @code{-r} and @code{-s} options.
1127 @item --stop-address=@var{address}
1128 @cindex stop-address
1129 Stop displaying data at the specified address. This affects the output
1130 of the @code{-d}, @code{-r} and @code{-s} options.
1134 @cindex symbol table entries, printing
1135 Print the symbol table entries of the file.
1136 This is similar to the information provided by the @samp{nm} program.
1139 @itemx --dynamic-syms
1140 @cindex dynamic symbol table entries, printing
1141 Print the dynamic symbol table entries of the file. This is only
1142 meaningful for dynamic objects, such as certain types of shared
1143 libraries. This is similar to the information provided by the @samp{nm}
1144 program when given the @samp{-D} (@samp{--dynamic}) option.
1147 Print the version number of @code{objdump} and exit.
1151 @cindex all header information, object file
1152 @cindex header information, all
1153 Display all available header information, including the symbol table and
1154 relocation entries. Using @samp{-x} is equivalent to specifying all of
1155 @samp{-a -f -h -r -t}.
1159 @cindex wide output, printing
1160 Format some lines for output devices that have more than 80 columns.
1167 @cindex archive contents
1168 @cindex symbol index
1171 ranlib [-vV] @var{archive}
1174 @code{ranlib} generates an index to the contents of an archive and
1175 stores it in the archive. The index lists each symbol defined by a
1176 member of an archive that is a relocatable object file.
1178 You may use @samp{nm -s} or @samp{nm --print-armap} to list this index.
1180 An archive with such an index speeds up linking to the library and
1181 allows routines in the library to call each other without regard to
1182 their placement in the archive.
1184 The @sc{gnu} @code{ranlib} program is another form of @sc{gnu} @code{ar}; running
1185 @code{ranlib} is completely equivalent to executing @samp{ar -s}.
1191 Show the version number of @code{ranlib}.
1198 @cindex section sizes
1201 size [ -A | -B | --format=@var{compatibility} ]
1202 [ --help ] [ -d | -o | -x | --radix=@var{number} ]
1203 [ --target=@var{bfdname} ] [ -V | --version ]
1204 @var{objfile}@dots{}
1207 The @sc{gnu} @code{size} utility lists the section sizes---and the total
1208 size---for each of the object or archive files @var{objfile} in its
1209 argument list. By default, one line of output is generated for each
1210 object file or each module in an archive.
1212 @var{objfile}@dots{} are the object files to be examined.
1214 The command line options have the following meanings:
1219 @itemx --format=@var{compatibility}
1220 @cindex @code{size} display format
1221 Using one of these options, you can choose whether the output from @sc{gnu}
1222 @code{size} resembles output from System V @code{size} (using @samp{-A},
1223 or @samp{--format=sysv}), or Berkeley @code{size} (using @samp{-B}, or
1224 @samp{--format=berkeley}). The default is the one-line format similar to
1226 @c Bonus for doc-source readers: you can also say --format=strange (or
1227 @c anything else that starts with 's') for sysv, and --format=boring (or
1228 @c anything else that starts with 'b') for Berkeley.
1230 Here is an example of the Berkeley (default) format of output from
1233 size --format=Berkeley ranlib size
1234 text data bss dec hex filename
1235 294880 81920 11592 388392 5ed28 ranlib
1236 294880 81920 11888 388688 5ee50 size
1240 This is the same data, but displayed closer to System V conventions:
1243 size --format=SysV ranlib size
1261 Show a summary of acceptable arguments and options.
1266 @itemx --radix=@var{number}
1267 @cindex @code{size} number format
1268 @cindex radix for section sizes
1269 Using one of these options, you can control whether the size of each
1270 section is given in decimal (@samp{-d}, or @samp{--radix=10}); octal
1271 (@samp{-o}, or @samp{--radix=8}); or hexadecimal (@samp{-x}, or
1272 @samp{--radix=16}). In @samp{--radix=@var{number}}, only the three
1273 values (8, 10, 16) are supported. The total size is always given in two
1274 radices; decimal and hexadecimal for @samp{-d} or @samp{-x} output, or
1275 octal and hexadecimal if you're using @samp{-o}.
1277 @item --target=@var{bfdname}
1278 @cindex object code format
1279 Specify that the object-code format for @var{objfile} is
1280 @var{bfdname}. This option may not be necessary; @code{size} can
1281 automatically recognize many formats.
1282 @xref{Target Selection}, for more information.
1286 Display the version number of @code{size}.
1292 @cindex listings strings
1293 @cindex printing strings
1294 @cindex strings, printing
1297 strings [-afov] [-@var{min-len}] [-n @var{min-len}] [-t @var{radix}] [-]
1298 [--all] [--print-file-name] [--bytes=@var{min-len}]
1299 [--radix=@var{radix}] [--target=@var{bfdname}]
1300 [--help] [--version] @var{file}@dots{}
1303 For each @var{file} given, @sc{gnu} @code{strings} prints the printable
1304 character sequences that are at least 4 characters long (or the number
1305 given with the options below) and are followed by an unprintable
1306 character. By default, it only prints the strings from the initialized
1307 and loaded sections of object files; for other types of files, it prints
1308 the strings from the whole file.
1310 @code{strings} is mainly useful for determining the contents of non-text
1317 Do not scan only the initialized and loaded sections of object files;
1318 scan the whole files.
1321 @itemx --print-file-name
1322 Print the name of the file before each string.
1325 Print a summary of the program usage on the standard output and exit.
1327 @itemx -@var{min-len}
1328 @item -n @var{min-len}
1329 @itemx --bytes=@var{min-len}
1330 Print sequences of characters that are at least @var{min-len} characters
1331 long, instead of the default 4.
1334 Like @samp{-t o}. Some other versions of @code{strings} have @samp{-o}
1335 act like @samp{-t d} instead. Since we can not be compatible with both
1336 ways, we simply chose one.
1338 @item -t @var{radix}
1339 @itemx --radix=@var{radix}
1340 Print the offset within the file before each string. The single
1341 character argument specifies the radix of the offset---@samp{o} for
1342 octal, @samp{x} for hexadecimal, or @samp{d} for decimal.
1344 @item --target=@var{bfdname}
1345 @cindex object code format
1346 Specify an object code format other than your system's default format.
1347 @xref{Target Selection}, for more information.
1351 Print the program version number on the standard output and exit.
1358 @cindex removing symbols
1359 @cindex discarding symbols
1360 @cindex symbols, discarding
1363 strip [ -F @var{bfdname} | --target=@var{bfdname} | --target=@var{bfdname} ]
1364 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1365 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1366 [ -s | --strip-all ] [ -S | -g | --strip-debug ]
1367 [ -K @var{symbolname} | --keep-symbol=@var{symbolname} ]
1368 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
1369 [ -x | --discard-all ] [ -X | --discard-locals ]
1370 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
1371 [ -v | --verbose ] [ -V | --version ] [ --help ]
1372 @var{objfile}@dots{}
1375 @sc{gnu} @code{strip} discards all symbols from object files
1376 @var{objfile}. The list of object files may include archives.
1377 At least one object file must be given.
1379 @code{strip} modifies the files named in its argument,
1380 rather than writing modified copies under different names.
1383 @item -F @var{bfdname}
1384 @itemx --target=@var{bfdname}
1385 Treat the original @var{objfile} as a file with the object
1386 code format @var{bfdname}, and rewrite it in the same format.
1387 @xref{Target Selection}, for more information.
1390 Show a summary of the options to @code{strip} and exit.
1392 @item -I @var{bfdname}
1393 @itemx --input-target=@var{bfdname}
1394 Treat the original @var{objfile} as a file with the object
1395 code format @var{bfdname}.
1396 @xref{Target Selection}, for more information.
1398 @item -O @var{bfdname}
1399 @itemx --output-target=@var{bfdname}
1400 Replace @var{objfile} with a file in the output format @var{bfdname}.
1401 @xref{Target Selection}, for more information.
1403 @item -R @var{sectionname}
1404 @itemx --remove-section=@var{sectionname}
1405 Remove any section named @var{sectionname} from the output file. This
1406 option may be given more than once. Note that using this option
1407 inappropriately may make the output file unusable.
1415 @itemx --strip-debug
1416 Remove debugging symbols only.
1418 @item --strip-unneeded
1419 Remove all symbols that are not needed for relocation processing.
1421 @item -K @var{symbolname}
1422 @itemx --keep-symbol=@var{symbolname}
1423 Keep only symbol @var{symbolname} from the source file. This option may
1424 be given more than once.
1426 @item -N @var{symbolname}
1427 @itemx --strip-symbol=@var{symbolname}
1428 Remove symbol @var{symbolname} from the source file. This option may be
1429 given more than once, and may be combined with strip options other than
1433 @itemx --discard-all
1434 Remove non-global symbols.
1437 @itemx --discard-locals
1438 Remove compiler-generated local symbols.
1439 (These usually start with @samp{L} or @samp{.}.)
1443 Show the version number for @code{strip}.
1447 Verbose output: list all object files modified. In the case of
1448 archives, @samp{strip -v} lists all members of the archive.
1455 @cindex demangling C++ symbols
1458 c++filt [ -_ | --strip-underscores ]
1459 [ -n | --no-strip-underscores ]
1460 [ -s @var{format} | --format=@var{format} ]
1461 [ --help ] [ --version ] [ @var{symbol}@dots{} ]
1464 The C++ language provides function overloading, which means that you can
1465 write many functions with the same name (providing each takes parameters
1466 of different types). All C++ function names are encoded into a
1467 low-level assembly label (this process is known as
1468 @dfn{mangling}). The @code{c++filt} program does the inverse mapping: it
1469 decodes (@dfn{demangles}) low-level names into user-level names so that
1470 the linker can keep these overloaded functions from clashing.
1472 Every alphanumeric word (consisting of letters, digits, underscores,
1473 dollars, or periods) seen in the input is a potential label. If the
1474 label decodes into a C++ name, the C++ name replaces the low-level
1477 You can use @code{c++filt} to decipher individual symbols:
1480 c++filt @var{symbol}
1483 If no @var{symbol} arguments are given, @code{c++filt} reads symbol
1484 names from the standard input and writes the demangled names to the
1485 standard output. All results are printed on the standard output.
1489 @itemx --strip-underscores
1490 On some systems, both the C and C++ compilers put an underscore in front
1491 of every name. For example, the C name @code{foo} gets the low-level
1492 name @code{_foo}. This option removes the initial underscore. Whether
1493 @code{c++filt} removes the underscore by default is target dependent.
1496 @itemx --no-strip-underscores
1497 Do not remove the initial underscore.
1499 @item -s @var{format}
1500 @itemx --format=@var{format}
1501 @sc{gnu} @code{nm} can decode three different methods of mangling, used by
1502 different C++ compilers. The argument to this option selects which
1507 the one used by the @sc{gnu} compiler (the default method)
1509 the one used by the Lucid compiler
1511 the one specified by the C++ Annotated Reference Manual
1515 Print a summary of the options to @code{c++filt} and exit.
1518 Print the version number of @code{c++filt} and exit.
1522 @emph{Warning:} @code{c++filt} is a new utility, and the details of its
1523 user interface are subject to change in future releases. In particular,
1524 a command-line option may be required in the the future to decode a name
1525 passed as an argument on the command line; in other words,
1528 c++filt @var{symbol}
1532 may in a future release become
1535 c++filt @var{option} @var{symbol}
1542 @code{nlmconv} converts a relocatable object file into a NetWare
1546 @code{nlmconv} currently works with @samp{i386} object
1547 files in @code{coff}, @sc{elf}, or @code{a.out} format, and @sc{SPARC}
1548 object files in @sc{elf}, or @code{a.out} format@footnote{
1549 @code{nlmconv} should work with any @samp{i386} or @sc{sparc} object
1550 format in the Binary File Descriptor library. It has only been tested
1551 with the above formats.}.
1555 @emph{Warning:} @code{nlmconv} is not always built as part of the binary
1556 utilities, since it is only useful for NLM targets.
1560 nlmconv [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1561 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1562 [ -T @var{headerfile} | --header-file=@var{headerfile} ]
1563 [ -d | --debug] [ -l @var{linker} | --linker=@var{linker} ]
1564 [ -h | --help ] [ -V | --version ]
1565 @var{infile} @var{outfile}
1568 @code{nlmconv} converts the relocatable @samp{i386} object file
1569 @var{infile} into the NetWare Loadable Module @var{outfile}, optionally
1570 reading @var{headerfile} for NLM header information. For instructions
1571 on writing the NLM command file language used in header files, see the
1572 @samp{linkers} section, @samp{NLMLINK} in particular, of the @cite{NLM
1573 Development and Tools Overview}, which is part of the NLM Software
1574 Developer's Kit (``NLM SDK''), available from Novell, Inc.
1575 @code{nlmconv} uses the @sc{gnu} Binary File Descriptor library to read
1576 @var{infile}; see @ref{BFD,,BFD,ld.info,Using LD}, for
1579 @code{nlmconv} can perform a link step. In other words, you can list
1580 more than one object file for input if you list them in the definitions
1581 file (rather than simply specifying one input file on the command line).
1582 In this case, @code{nlmconv} calls the linker for you.
1585 @item -I @var{bfdname}
1586 @itemx --input-target=@var{bfdname}
1587 Object format of the input file. @code{nlmconv} can usually determine
1588 the format of a given file (so no default is necessary).
1589 @xref{Target Selection}, for more information.
1591 @item -O @var{bfdname}
1592 @itemx --output-target=@var{bfdname}
1593 Object format of the output file. @code{nlmconv} infers the output
1594 format based on the input format, e.g. for a @samp{i386} input file the
1595 output format is @samp{nlm32-i386}.
1596 @xref{Target Selection}, for more information.
1598 @item -T @var{headerfile}
1599 @itemx --header-file=@var{headerfile}
1600 Reads @var{headerfile} for NLM header information. For instructions on
1601 writing the NLM command file language used in header files, see@ see the
1602 @samp{linkers} section, of the @cite{NLM Development and Tools
1603 Overview}, which is part of the NLM Software Developer's Kit, available
1608 Displays (on standard error) the linker command line used by @code{nlmconv}.
1610 @item -l @var{linker}
1611 @itemx --linker=@var{linker}
1612 Use @var{linker} for any linking. @var{linker} can be an abosolute or a
1617 Prints a usage summary.
1621 Prints the version number for @code{nlmconv}.
1624 @node Selecting The Target System
1625 @chapter Selecting the target system
1627 You can specify three aspects of the target system to the @sc{gnu}
1628 binary file utilities, each in several ways:
1638 the linker emulation (which applies to the linker only)
1641 In the following summaries, the lists of ways to specify values are in
1642 order of decreasing precedence. The ways listed first override those
1645 The commands to list valid values only list the values for which the
1646 programs you are running were configured. If they were configured with
1647 @samp{--enable-targets=all}, the commands list most of the available
1648 values, but a few are left out; not all targets can be configured in at
1649 once because some of them can only be configured @dfn{native} (on hosts
1650 with the same type as the target system).
1653 * Target Selection::
1654 * Architecture Selection::
1655 * Linker Emulation Selection::
1658 @node Target Selection
1659 @section Target Selection
1661 A @dfn{target} is an object file format. A given target may be
1662 supported for multiple architectures (@pxref{Architecture Selection}).
1663 A target selection may also have variations for different operating
1664 systems or architectures.
1666 The command to list valid target values is @samp{objdump -i}
1667 (the first column of output contains the relevant information).
1669 Some sample values are: @samp{a.out-hp300bsd}, @samp{ecoff-littlemips},
1670 @samp{a.out-sunos-big}.
1672 @subheading @code{objdump} Target
1678 command line option: @samp{-b} or @samp{--target}
1681 environment variable @code{GNUTARGET}
1684 deduced from the input file
1687 @subheading @code{objcopy} and @code{strip} Input Target
1693 command line options: @samp{-I} or @samp{--input-target}, or @samp{-F} or @samp{--target}
1696 environment variable @code{GNUTARGET}
1699 deduced from the input file
1702 @subheading @code{objcopy} and @code{strip} Output Target
1708 command line options: @samp{-O} or @samp{--output-target}, or @samp{-F} or @samp{--target}
1711 the input target (see ``@code{objcopy} and @code{strip} Input Target'' above)
1714 environment variable @code{GNUTARGET}
1717 deduced from the input file
1720 @subheading @code{nm}, @code{size}, and @code{strings} Target
1726 command line option: @samp{--target}
1729 environment variable @code{GNUTARGET}
1732 deduced from the input file
1735 @subheading Linker Input Target
1741 command line option: @samp{-b} or @samp{--format}
1742 (@pxref{Options,,Options,ld.info,Using LD})
1745 script command @code{TARGET}
1746 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1749 environment variable @code{GNUTARGET}
1750 (@pxref{Environment,,Environment,ld.info,Using LD})
1753 the default target of the selected linker emulation
1754 (@pxref{Linker Emulation Selection})
1757 @subheading Linker Output Target
1763 command line option: @samp{-oformat}
1764 (@pxref{Options,,Options,ld.info,Using LD})
1767 script command @code{OUTPUT_FORMAT}
1768 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1771 the linker input target (see ``Linker Input Target'' above)
1774 @node Architecture Selection
1775 @section Architecture selection
1777 An @dfn{architecture} is a type of @sc{cpu} on which an object file is
1778 to run. Its name may contain a colon, separating the name of the
1779 processor family from the name of the particular @sc{cpu}.
1781 The command to list valid architecture values is @samp{objdump -i} (the
1782 second column contains the relevant information).
1784 Sample values: @samp{m68k:68020}, @samp{mips:3000}, @samp{sparc}.
1786 @subheading @code{objdump} Architecture
1792 command line option: @samp{-m} or @samp{--architecture}
1795 deduced from the input file
1798 @subheading @code{objcopy}, @code{nm}, @code{size}, @code{strings} Architecture
1804 deduced from the input file
1807 @subheading Linker Input Architecture
1813 deduced from the input file
1816 @subheading Linker Output Architecture
1822 script command @code{OUTPUT_ARCH}
1823 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1826 the default architecture from the linker output target
1827 (@pxref{Target Selection})
1830 @node Linker Emulation Selection
1831 @section Linker emulation selection
1833 A linker @dfn{emulation} is a ``personality'' of the linker, which gives
1834 the linker default values for the other aspects of the target system.
1835 In particular, it consists of
1845 several ``hook'' functions that are run at certain stages of the linking
1846 process to do special things that some targets require
1849 The command to list valid linker emulation values is @samp{ld -V}.
1851 Sample values: @samp{hp300bsd}, @samp{mipslit}, @samp{sun4}.
1857 command line option: @samp{-m}
1858 (@pxref{Options,,Options,ld.info,Using LD})
1861 environment variable @code{LDEMULATION}
1864 compiled-in @code{DEFAULT_EMULATION} from @file{Makefile},
1865 which comes from @code{EMUL} in @file{config/@var{target}.mt}