1 \input texinfo @c -*- Texinfo -*-
2 @setfilename binutils.info
7 * Binutils: (binutils). The GNU binary utilities "ar", "objcopy",
8 "objdump", "nm", "nlmconv", "size",
9 "strings", "strip", and "ranlib".
15 Copyright @copyright{} 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
17 Permission is granted to make and distribute verbatim copies of
18 this manual provided the copyright notice and this permission notice
19 are preserved on all copies.
22 Permission is granted to process this file through TeX and print the
23 results, provided the printed document carries a copying permission
24 notice identical to this one except for the removal of this paragraph
25 (this paragraph not being relevant to the printed manual).
29 Permission is granted to copy and distribute modified versions of this
30 manual under the conditions for verbatim copying, provided also that
31 the entire resulting derived work is distributed under the terms of a
32 permission notice identical to this one.
34 Permission is granted to copy and distribute translations of this manual
35 into another language, under the above conditions for modified versions.
40 @c This file documents the GNU binary utilities "ar", "ld", "objcopy",
41 @c "objdump", "nm", "size", "strings", "strip", and "ranlib".
43 @c Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
45 @c This text may be freely distributed under the terms of the GNU
46 @c General Public License.
49 @setchapternewpage odd
50 @settitle GNU Binary Utilities
53 @title The GNU Binary Utilities
57 @author Roland H. Pesch
58 @author Jeffrey M. Osier
59 @author Cygnus Support
63 {\parskip=0pt \hfill Cygnus Support\par \hfill
64 \TeX{}info \texinfoversion\par }
67 @vskip 0pt plus 1filll
68 Copyright @copyright{} 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
70 Permission is granted to make and distribute verbatim copies of
71 this manual provided the copyright notice and this permission notice
72 are preserved on all copies.
74 Permission is granted to copy and distribute modified versions of this
75 manual under the conditions for verbatim copying, provided also that
76 the entire resulting derived work is distributed under the terms of a
77 permission notice identical to this one.
79 Permission is granted to copy and distribute translations of this manual
80 into another language, under the above conditions for modified versions.
87 This brief manual contains preliminary documentation for the GNU binary
88 utilities (collectively version 2.2):
93 Create, modify, and extract from archives
96 List symbols from object files
99 Copy and translate object files
102 Display information from object files
105 Generate index to archive contents
108 List file section sizes and total size
111 List printable strings from files
117 Demangle encoded C++ symbols
120 Convert object code into a Netware Loadable Module
125 * ar:: Create, modify, and extract from archives
126 * nm:: List symbols from object files
127 * objcopy:: Copy and translate object files
128 * objdump:: Display information from object files
129 * ranlib:: Generate index to archive contents
130 * size:: List section sizes and total size
131 * strings:: List printable strings from files
132 * strip:: Discard symbols
133 * c++filt:: Filter to demangle encoded C++ symbols
134 * nlmconv:: Converts object code into an NLM
135 * Selecting The Target System:: How these utilities determine the target.
144 @cindex collections of files
146 ar [-]@var{p}[@var{mod} [@var{relpos}]] @var{archive} [@var{member}@dots{}]
147 ar -M [ <mri-script ]
150 The GNU @code{ar} program creates, modifies, and extracts from
151 archives. An @dfn{archive} is a single file holding a collection of
152 other files in a structure that makes it possible to retrieve
153 the original individual files (called @dfn{members} of the archive).
155 The original files' contents, mode (permissions), timestamp, owner, and
156 group are preserved in the archive, and can be restored on
160 GNU @code{ar} can maintain archives whose members have names of any
161 length; however, depending on how @code{ar} is configured on your
162 system, a limit on member-name length may be imposed for compatibility
163 with archive formats maintained with other tools. If it exists, the
164 limit is often 15 characters (typical of formats related to a.out) or 16
165 characters (typical of formats related to coff).
168 @code{ar} is considered a binary utility because archives of this sort
169 are most often used as @dfn{libraries} holding commonly needed
173 @code{ar} creates an index to the symbols defined in relocatable
174 object modules in the archive when you specify the modifier @samp{s}.
175 Once created, this index is updated in the archive whenever @code{ar}
176 makes a change to its contents (save for the @samp{q} update operation).
177 An archive with such an index speeds up linking to the library, and
178 allows routines in the library to call each other without regard to
179 their placement in the archive.
181 You may use @samp{nm -s} or @samp{nm --print-armap} to list this index
182 table. If an archive lacks the table, another form of @code{ar} called
183 @code{ranlib} can be used to add just the table.
185 @cindex compatibility, @code{ar}
186 @cindex @code{ar} compatibility
187 GNU @code{ar} is designed to be compatible with two different
188 facilities. You can control its activity using command-line options,
189 like the different varieties of @code{ar} on Unix systems; or, if you
190 specify the single command-line option @samp{-M}, you can control it
191 with a script supplied via standard input, like the MRI ``librarian''
195 * ar cmdline:: Controlling @code{ar} on the command line
196 * ar scripts:: Controlling @code{ar} with a script
201 @section Controlling @code{ar} on the command line
204 ar [-]@var{p}[@var{mod} [@var{relpos}]] @var{archive} [@var{member}@dots{}]
207 @cindex Unix compatibility, @code{ar}
208 When you use @code{ar} in the Unix style, @code{ar} insists on at least two
209 arguments to execute: one keyletter specifying the @emph{operation}
210 (optionally accompanied by other keyletters specifying
211 @emph{modifiers}), and the archive name to act on.
213 Most operations can also accept further @var{member} arguments,
214 specifying particular files to operate on.
216 GNU @code{ar} allows you to mix the operation code @var{p} and modifier
217 flags @var{mod} in any order, within the first command-line argument.
219 If you wish, you may begin the first command-line argument with a
222 @cindex operations on archive
223 The @var{p} keyletter specifies what operation to execute; it may be
224 any of the following, but you must specify only one of them:
228 @cindex deleting from archive
229 @emph{Delete} modules from the archive. Specify the names of modules to
230 be deleted as @var{member}@dots{}; the archive is untouched if you
231 specify no files to delete.
233 If you specify the @samp{v} modifier, @code{ar} lists each module
237 @cindex moving in archive
238 Use this operation to @emph{move} members in an archive.
240 The ordering of members in an archive can make a difference in how
241 programs are linked using the library, if a symbol is defined in more
244 If no modifiers are used with @code{m}, any members you name in the
245 @var{member} arguments are moved to the @emph{end} of the archive;
246 you can use the @samp{a}, @samp{b}, or @samp{i} modifiers to move them to a
247 specified place instead.
250 @cindex printing from archive
251 @emph{Print} the specified members of the archive, to the standard
252 output file. If the @samp{v} modifier is specified, show the member
253 name before copying its contents to standard output.
255 If you specify no @var{member} arguments, all the files in the archive are
259 @cindex quick append to archive
260 @emph{Quick append}; add the files @var{member}@dots{} to the end of
261 @var{archive}, without checking for replacement.
263 The modifiers @samp{a}, @samp{b}, and @samp{i} do @emph{not} affect this
264 operation; new members are always placed at the end of the archive.
266 The modifier @samp{v} makes @code{ar} list each file as it is appended.
268 Since the point of this operation is speed, the archive's symbol table
269 index is not updated, even if it already existed; you can use @samp{ar s} or
270 @code{ranlib} explicitly to update the symbol table index.
273 @cindex replacement in archive
274 Insert the files @var{member}@dots{} into @var{archive} (with
275 @emph{replacement}). This operation differs from @samp{q} in that any
276 previously existing members are deleted if their names match those being
279 If one of the files named in @var{member}@dots{} does not exist, @code{ar}
280 displays an error message, and leaves undisturbed any existing members
281 of the archive matching that name.
283 By default, new members are added at the end of the file; but you may
284 use one of the modifiers @samp{a}, @samp{b}, or @samp{i} to request
285 placement relative to some existing member.
287 The modifier @samp{v} used with this operation elicits a line of
288 output for each file inserted, along with one of the letters @samp{a} or
289 @samp{r} to indicate whether the file was appended (no old member
290 deleted) or replaced.
293 @cindex contents of archive
294 Display a @emph{table} listing the contents of @var{archive}, or those
295 of the files listed in @var{member}@dots{} that are present in the
296 archive. Normally only the member name is shown; if you also want to
297 see the modes (permissions), timestamp, owner, group, and size, you can
298 request that by also specifying the @samp{v} modifier.
300 If you do not specify a @var{member}, all files in the archive
303 @cindex repeated names in archive
304 @cindex name duplication in archive
305 If there is more than one file with the same name (say, @samp{fie}) in
306 an archive (say @samp{b.a}), @samp{ar t b.a fie} lists only the
307 first instance; to see them all, you must ask for a complete
308 listing---in our example, @samp{ar t b.a}.
309 @c WRS only; per Gumby, this is implementation-dependent, and in a more
310 @c recent case in fact works the other way.
313 @cindex extract from archive
314 @emph{Extract} members (named @var{member}) from the archive. You can
315 use the @samp{v} modifier with this operation, to request that
316 @code{ar} list each name as it extracts it.
318 If you do not specify a @var{member}, all files in the archive
323 A number of modifiers (@var{mod}) may immediately follow the @var{p}
324 keyletter, to specify variations on an operation's behavior:
328 @cindex relative placement in archive
329 Add new files @emph{after} an existing member of the
330 archive. If you use the modifier @samp{a}, the name of an existing archive
331 member must be present as the @var{relpos} argument, before the
332 @var{archive} specification.
335 Add new files @emph{before} an existing member of the
336 archive. If you use the modifier @samp{b}, the name of an existing archive
337 member must be present as the @var{relpos} argument, before the
338 @var{archive} specification. (same as @samp{i}).
341 @cindex creating archives
342 @emph{Create} the archive. The specified @var{archive} is always
343 created if it did not exist, when you request an update. But a warning is
344 issued unless you specify in advance that you expect to create it, by
348 Insert new files @emph{before} an existing member of the
349 archive. If you use the modifier @samp{i}, the name of an existing archive
350 member must be present as the @var{relpos} argument, before the
351 @var{archive} specification. (same as @samp{b}).
354 This modifier is accepted but not used.
355 @c whaffor ar l modifier??? presumably compat; with
356 @c what???---pesch@@cygnus.com, 25jan91
359 @cindex dates in archive
360 Preserve the @emph{original} dates of members when extracting them. If
361 you do not specify this modifier, files extracted from the archive
362 are stamped with the time of extraction.
365 @cindex writing archive index
366 Write an object-file index into the archive, or update an existing one,
367 even if no other change is made to the archive. You may use this modifier
368 flag either with any operation, or alone. Running @samp{ar s} on an
369 archive is equivalent to running @samp{ranlib} on it.
372 @cindex updating an archive
373 Normally, @samp{ar r}@dots{} inserts all files
374 listed into the archive. If you would like to insert @emph{only} those
375 of the files you list that are newer than existing members of the same
376 names, use this modifier. The @samp{u} modifier is allowed only for the
377 operation @samp{r} (replace). In particular, the combination @samp{qu} is
378 not allowed, since checking the timestamps would lose any speed
379 advantage from the operation @samp{q}.
382 This modifier requests the @emph{verbose} version of an operation. Many
383 operations display additional information, such as filenames processed,
384 when the modifier @samp{v} is appended.
387 This modifier shows the version number of @code{ar}.
391 @section Controlling @code{ar} with a script
394 ar -M [ <@var{script} ]
397 @cindex MRI compatibility, @code{ar}
398 @cindex scripts, @code{ar}
399 If you use the single command-line option @samp{-M} with @code{ar}, you
400 can control its operation with a rudimentary command language. This
401 form of @code{ar} operates interactively if standard input is coming
402 directly from a terminal. During interactive use, @code{ar} prompts for
403 input (the prompt is @samp{AR >}), and continues executing even after
404 errors. If you redirect standard input to a script file, no prompts are
405 issued, and @code{ar} abandons execution (with a nonzero exit code)
408 The @code{ar} command language is @emph{not} designed to be equivalent
409 to the command-line options; in fact, it provides somewhat less control
410 over archives. The only purpose of the command language is to ease the
411 transition to GNU @code{ar} for developers who already have scripts
412 written for the MRI ``librarian'' program.
414 The syntax for the @code{ar} command language is straightforward:
417 commands are recognized in upper or lower case; for example, @code{LIST}
418 is the same as @code{list}. In the following descriptions, commands are
419 shown in upper case for clarity.
422 a single command may appear on each line; it is the first word on the
426 empty lines are allowed, and have no effect.
429 comments are allowed; text after either of the characters @samp{*}
430 or @samp{;} is ignored.
433 Whenever you use a list of names as part of the argument to an @code{ar}
434 command, you can separate the individual names with either commas or
435 blanks. Commas are shown in the explanations below, for clarity.
438 @samp{+} is used as a line continuation character; if @samp{+} appears
439 at the end of a line, the text on the following line is considered part
440 of the current command.
443 Here are the commands you can use in @code{ar} scripts, or when using
444 @code{ar} interactively. Three of them have special significance:
446 @code{OPEN} or @code{CREATE} specify a @dfn{current archive}, which is
447 a temporary file required for most of the other commands.
449 @code{SAVE} commits the changes so far specified by the script. Prior
450 to @code{SAVE}, commands affect only the temporary copy of the current
454 @item ADDLIB @var{archive}
455 @itemx ADDLIB @var{archive} (@var{module}, @var{module}, @dots{} @var{module})
456 Add all the contents of @var{archive} (or, if specified, each named
457 @var{module} from @var{archive}) to the current archive.
459 Requires prior use of @code{OPEN} or @code{CREATE}.
461 @item ADDMOD @var{member}, @var{member}, @dots{} @var{member}
462 @c FIXME! w/Replacement?? If so, like "ar r @var{archive} @var{names}"
463 @c else like "ar q..."
464 Add each named @var{member} as a module in the current archive.
466 Requires prior use of @code{OPEN} or @code{CREATE}.
469 Discard the contents of the current archive, cancelling the effect of
470 any operations since the last @code{SAVE}. May be executed (with no
471 effect) even if no current archive is specified.
473 @item CREATE @var{archive}
474 Creates an archive, and makes it the current archive (required for many
475 other commands). The new archive is created with a temporary name; it
476 is not actually saved as @var{archive} until you use @code{SAVE}.
477 You can overwrite existing archives; similarly, the contents of any
478 existing file named @var{archive} will not be destroyed until @code{SAVE}.
480 @item DELETE @var{module}, @var{module}, @dots{} @var{module}
481 Delete each listed @var{module} from the current archive; equivalent to
482 @samp{ar -d @var{archive} @var{module} @dots{} @var{module}}.
484 Requires prior use of @code{OPEN} or @code{CREATE}.
486 @item DIRECTORY @var{archive} (@var{module}, @dots{} @var{module})
487 @itemx DIRECTORY @var{archive} (@var{module}, @dots{} @var{module}) @var{outputfile}
488 List each named @var{module} present in @var{archive}. The separate
489 command @code{VERBOSE} specifies the form of the output: when verbose
490 output is off, output is like that of @samp{ar -t @var{archive}
491 @var{module}@dots{}}. When verbose output is on, the listing is like
492 @samp{ar -tv @var{archive} @var{module}@dots{}}.
494 Output normally goes to the standard output stream; however, if you
495 specify @var{outputfile} as a final argument, @code{ar} directs the
499 Exit from @code{ar}, with a @code{0} exit code to indicate successful
500 completion. This command does not save the output file; if you have
501 changed the current archive since the last @code{SAVE} command, those
504 @item EXTRACT @var{module}, @var{module}, @dots{} @var{module}
505 Extract each named @var{module} from the current archive, writing them
506 into the current directory as separate files. Equivalent to @samp{ar -x
507 @var{archive} @var{module}@dots{}}.
509 Requires prior use of @code{OPEN} or @code{CREATE}.
512 @c FIXME Tokens but no commands???
519 Display full contents of the current archive, in ``verbose'' style
520 regardless of the state of @code{VERBOSE}. The effect is like @samp{ar
521 tv @var{archive}}). (This single command is a GNU @code{ld}
522 enhancement, rather than present for MRI compatibility.)
524 Requires prior use of @code{OPEN} or @code{CREATE}.
526 @item OPEN @var{archive}
527 Opens an existing archive for use as the current archive (required for
528 many other commands). Any changes as the result of subsequent commands
529 will not actually affect @var{archive} until you next use @code{SAVE}.
531 @item REPLACE @var{module}, @var{module}, @dots{} @var{module}
532 In the current archive, replace each existing @var{module} (named in
533 the @code{REPLACE} arguments) from files in the current working directory.
534 To execute this command without errors, both the file, and the module in
535 the current archive, must exist.
537 Requires prior use of @code{OPEN} or @code{CREATE}.
540 Toggle an internal flag governing the output from @code{DIRECTORY}.
541 When the flag is on, @code{DIRECTORY} output matches output from
542 @samp{ar -tv }@dots{}.
545 Commit your changes to the current archive, and actually save it as a
546 file with the name specified in the last @code{CREATE} or @code{OPEN}
549 Requires prior use of @code{OPEN} or @code{CREATE}.
558 The GNU linker @code{ld} is now described in a separate manual.
559 @xref{Top,, Overview,, Using LD: the GNU linker}.
568 nm [ -a | --debug-syms ] [ -g | --extern-only ]
569 [ -B ] [ -C | --demangle ] [ -D | --dynamic ]
570 [ -s | --print-armap ] [ -A | -o | --print-file-name ]
571 [ -n | -v | --numeric-sort ] [ -p | --no-sort ]
572 [ -r | --reverse-sort ] [ --size-sort ] [ -u | --undefined-only ]
573 [ -t @var{radix} | --radix=@var{radix} ] [ -P | --portability ]
574 [ --target=@var{bfdname} ] [ -f @var{format} | --format=@var{format} ]
575 [ --no-demangle ] [ -V | --version ] [ --help ] [ @var{objfile}@dots{} ]
578 GNU @code{nm} lists the symbols from object files @var{objfile}@dots{}.
579 If no object files are listed as arguments, @code{nm} assumes
582 For each symbol, @code{nm} shows:
586 The symbol value, in the radix selected by options (see below), or
587 hexadecimal by default.
590 The symbol type. At least the following types are used; others are, as
591 well, depending on the object file format. If lowercase, the symbol is
592 local; if uppercase, the symbol is global (external).
594 @c Some more detail on exactly what these symbol types are used for
601 BSS (uninitialized data).
623 The long and short forms of options, shown here as alternatives, are
629 @itemx --print-file-name
630 @cindex input file name
632 @cindex source file name
633 Precede each symbol by the name of the input file (or archive element)
634 in which it was found, rather than identifying the input file once only,
635 before all of its symbols.
639 @cindex debugging symbols
640 Display all symbols, even debugger-only symbols; normally these are not
644 @cindex @code{nm} format
645 @cindex @code{nm} compatibility
646 The same as @samp{--format=bsd} (for compatibility with the MIPS @code{nm}).
650 @cindex demangling C++ symbols
651 Decode (@dfn{demangle}) low-level symbol names into user-level names.
652 Besides removing any initial underscore prepended by the system, this
653 makes C++ function names readable. @xref{c++filt}, for more information
657 Do not demangle low-level symbol names. This is the default.
661 @cindex dynamic symbols
662 Display the dynamic symbols rather than the normal symbols. This is
663 only meaningful for dynamic objects, such as certain types of shared
666 @item -f @var{format}
667 @itemx --format=@var{format}
668 @cindex @code{nm} format
669 @cindex @code{nm} compatibility
670 Use the output format @var{format}, which can be @code{bsd},
671 @code{sysv}, or @code{posix}. The default is @code{bsd}.
672 Only the first character of @var{format} is significant; it can be
673 either upper or lower case.
677 @cindex external symbols
678 Display only external symbols.
682 @itemx --numeric-sort
683 Sort symbols numerically by their addresses, rather than alphabetically
688 @cindex sorting symbols
689 Do not bother to sort the symbols in any order; print them in the order
694 Use the POSIX.2 standard output format instead of the default format.
695 Equivalent to @samp{-f posix}.
699 @cindex symbol index, listing
700 When listing symbols from archive members, include the index: a mapping
701 (stored in the archive by @code{ar} or @code{ranlib}) of which modules
702 contain definitions for which names.
705 @itemx --reverse-sort
706 Reverse the order of the sort (whether numeric or alphabetic); let the
710 Sort symbols by size. The size is computed as the difference between
711 the value of the symbol and the value of the symbol with the next higher
712 value. The size of the symbol is printed, rather than the value.
715 @itemx --radix=@var{radix}
716 Use @var{radix} as the radix for printing the symbol values. It must be
717 @samp{d} for decimal, @samp{o} for octal, or @samp{x} for hexadecimal.
719 @item --target=@var{bfdname}
720 @cindex object code format
721 Specify an object code format other than your system's default format.
722 @xref{Target Selection}, for more information.
725 @itemx --undefined-only
726 @cindex external symbols
727 @cindex undefined symbols
728 Display only undefined symbols (those external to each object file).
732 Show the version number of @code{nm} and exit.
735 Show a summary of the options to @code{nm} and exit.
742 objcopy [ -F @var{bfdname} | --target=@var{bfdname} ]
743 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
744 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
745 [ -S | --strip-all ] [ -g | --strip-debug ]
746 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
747 [ -x | --discard-all ] [ -X | --discard-locals ]
748 [ -b @var{byte} | --byte=@var{byte} ]
749 [ -i @var{interleave} | --interleave=@var{interleave} ]
750 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
751 [ --gap-fill=@var{val} ] [ --pad-to=@var{address} ]
752 [ --set-start=@var{val} ] [ --adjust-start=@var{incr} ]
753 [ --adjust-vma=@var{incr} ]
754 [ --adjust-section-vma=@var{section}@{=,+,-@}@var{val} ]
755 [ --adjust-warnings ] [ --no-adjust-warnings ]
756 [ --set-section-flags=@var{section}=@var{flags} ]
757 [ --add-section=@var{sectionname}=@var{filename} ]
758 [ -v | --verbose ] [ -V | --version ] [ --help ]
759 @var{infile} [@var{outfile}]
762 The @sc{gnu} @code{objcopy} utility copies the contents of an object
763 file to another. @code{objcopy} uses the @sc{gnu} @sc{bfd} Library to
764 read and write the object files. It can write the destination object
765 file in a format different from that of the source object file. The
766 exact behavior of @code{objcopy} is controlled by command-line options.
768 @code{objcopy} creates temporary files to do its translations and
769 deletes them afterward. @code{objcopy} uses @sc{bfd} to do all its
770 translation work; it has access to all the formats described in @sc{bfd}
771 and thus is able to recognize most formats without being told
772 explicitly. @xref{BFD,,BFD,ld.info,Using LD}.
774 @code{objcopy} can be used to generate S-records by using an output
775 target of @samp{srec} (e.g., use @samp{-O srec}).
777 @code{objcopy} can be used to generate a raw binary file by using an
778 output target of @samp{binary} (e.g., use @samp{-O binary}). When
779 @code{objcopy} generates a raw binary file, it will essentially produce
780 a memory dump of the contents of the input object file. All symbols and
781 relocation information will be discarded. The memory dump will start at
782 the virtual address of the lowest section copied into the output file.
784 When generating an S-record or a raw binary file, it may be helpful to
785 use @samp{-S} to remove sections containing debugging information. In
786 some cases @samp{-R} will be useful to remove sections which contain
787 information which is not needed by the binary file.
792 The source and output files, respectively.
793 If you do not specify @var{outfile}, @code{objcopy} creates a
794 temporary file and destructively renames the result with
795 the name of @var{infile}.
797 @item -I @var{bfdname}
798 @itemx --input-target=@var{bfdname}
799 Consider the source file's object format to be @var{bfdname}, rather than
800 attempting to deduce it. @xref{Target Selection}, for more information.
802 @item -O @var{bfdname}
803 @itemx --output-target=@var{bfdname}
804 Write the output file using the object format @var{bfdname}.
805 @xref{Target Selection}, for more information.
807 @item -F @var{bfdname}
808 @itemx --target=@var{bfdname}
809 Use @var{bfdname} as the object format for both the input and the output
810 file; i.e., simply transfer data from source to destination with no
811 translation. @xref{Target Selection}, for more information.
813 @item -R @var{sectionname}
814 @itemx --remove-section=@var{sectionname}
815 Remove any section named @var{sectionname} from the output file. This
816 option may be given more than once. Note that using this option
817 inappropriately may make the output file unusable.
821 Do not copy relocation and symbol information from the source file.
825 Do not copy debugging symbols from the source file.
827 @item -N @var{symbolname}
828 @itemx --strip-symbol=@var{symbolname}
829 Do not copy symbol @var{symbolname} from the source file. This option
830 may be given more than once, and may be combined with other strip
835 Do not copy non-global symbols from the source file.
836 @c FIXME any reason to prefer "non-global" to "local" here?
839 @itemx --discard-locals
840 Do not copy compiler-generated local symbols.
841 (These usually start with @samp{L} or @samp{.}.)
844 @itemx --byte=@var{byte}
845 Keep only every @var{byte}th byte of the input file (header data is not
846 affected). @var{byte} can be in the range from 0 to @var{interleave}-1,
847 where @var{interleave} is given by the @samp{-i} or @samp{--interleave}
848 option, or the default of 4. This option is useful for creating files
849 to program @sc{rom}. It is typically used with an @code{srec} output
852 @item -i @var{interleave}
853 @itemx --interleave=@var{interleave}
854 Only copy one out of every @var{interleave} bytes. Select which byte to
855 copy with the @var{-b} or @samp{--byte} option. The default is 4.
856 @code{objcopy} ignores this option if you do not specify either @samp{-b} or
859 @item --gap-fill @var{val}
860 Fill gaps between sections with @var{val}. This is done by increasing
861 the size of the section with the lower address, and filling in the extra
862 space created with @var{val}.
864 @item --pad-to @var{address}
865 Pad the output file up to the virtual address @var{address}. This is
866 done by increasing the size of the last section. The extra space is
867 filled in with the value specified by @samp{--gap-fill} (default zero).
869 @item --set-start @var{val}
870 Set the address of the new file to @var{val}. Not all object file
871 formats support setting the start address.
873 @item --adjust-start @var{incr}
874 Adjust the start address by adding @var{incr}. Not all object file
875 formats support setting the start address.
877 @item --adjust-vma @var{incr}
878 Adjust the address of all sections, as well as the start address, by
879 adding @var{incr}. Some object file formats do not permit section
880 addresses to be changed arbitrarily. Note that this does not relocate
881 the sections; if the program expects sections to be loaded at a certain
882 address, and this option is used to change the sections such that they
883 are loaded at a different address, the program may fail.
885 @item --adjust-section-vma @var{section}@{=,+,-@}@var{val}
886 Set or adjust the address of the named @var{section}. If @samp{=} is
887 used, the section address is set to @var{val}. Otherwise, @var{val} is
888 added to or subtracted from the section address. See the comments under
889 @samp{--adjust-vma}, above. If @var{section} does not exist in the
890 input file, a warning will be issued, unless @samp{--no-adjust-warnings}
893 @item --adjust-warnings
894 If @samp{--adjust-section-vma} is used, and the named section does not
895 exist, issue a warning. This is the default.
897 @item --no-adjust-warnings
898 Do not issue a warning if @samp{--adjust-section-vma} is used, even if
899 the named section does not exist.
901 @item --set-section-flags @var{section}=@var{flags}
902 Set the flags for the named section. The @var{flags} argument is a
903 comma separated string of flag names. The recognized names are
904 @samp{alloc}, @samp{load}, @samp{readonly}, @samp{code}, @samp{data},
905 and @samp{rom}. Not all flags are meaningful for all object file
908 @item --add-section @var{sectionname}=@var{filename}
909 Add a new section named @var{sectionname} while copying the file. The
910 contents of the new section are taken from the file @var{filename}. The
911 size of the section will be the size of the file. This option only
912 works on file formats which can support sections with arbitrary names.
916 Show the version number of @code{objcopy}.
920 Verbose output: list all object files modified. In the case of
921 archives, @samp{objcopy -V} lists all members of the archive.
924 Show a summary of the options to @code{objcopy}.
930 @cindex object file information
934 objdump [ -a | --archive-headers ]
935 [ -b @var{bfdname} | --target=@var{bfdname} ]
936 [ -d | --disassemble ] [ -D | --disassemble-all ]
937 [ -f | --file-headers ]
938 [ -h | --section-headers | --headers ] [ -i | --info ]
939 [ -j @var{section} | --section=@var{section} ]
940 [ -l | --line-numbers ] [ -S | --source ]
941 [ -m @var{machine} | --architecture=@var{machine} ]
942 [ -r | --reloc ] [ -R | --dynamic-reloc ]
943 [ -s | --full-contents ] [ --stabs ]
944 [ -t | --syms ] [ -T | --dynamic-syms ] [ -x | --all-headers ]
945 [ --version ] [ --help ] @var{objfile}@dots{}
948 @code{objdump} displays information about one or more object files.
949 The options control what particular information to display. This
950 information is mostly useful to programmers who are working on the
951 compilation tools, as opposed to programmers who just want their
952 program to compile and work.
954 @var{objfile}@dots{} are the object files to be examined. When you
955 specify archives, @code{objdump} shows information on each of the member
958 The long and short forms of options, shown here as alternatives, are
959 equivalent. At least one option besides @samp{-l} must be given.
963 @itemx --archive-header
964 @cindex archive headers
965 If any of the @var{objfile} files are archives, display the archive
966 header information (in a format similar to @samp{ls -l}). Besides the
967 information you could list with @samp{ar tv}, @samp{objdump -a} shows
968 the object file format of each archive member.
970 @item -b @var{bfdname}
971 @itemx --target=@var{bfdname}
972 @cindex object code format
973 Specify that the object-code format for the object files is
974 @var{bfdname}. This option may not be necessary; @var{objdump} can
975 automatically recognize many formats.
979 objdump -b oasys -m vax -h fu.o
982 displays summary information from the section headers (@samp{-h}) of
983 @file{fu.o}, which is explicitly identified (@samp{-m}) as a VAX object
984 file in the format produced by Oasys compilers. You can list the
985 formats available with the @samp{-i} option.
986 @xref{Target Selection}, for more information.
990 @cindex disassembling object code
991 @cindex machine instructions
992 Display the assembler mnemonics for the machine instructions from
993 @var{objfile}. This option only disassembles those sections which are
994 expected to contain instructions.
997 @itemx --disassemble-all
998 Like @samp{-d}, but disassemble the contents of all sections, not just
999 those expected to contain instructions.
1002 @itemx --file-header
1003 @cindex object file header
1004 Display summary information from the overall header of
1005 each of the @var{objfile} files.
1008 @itemx --section-header
1010 @cindex section headers
1011 Display summary information from the section headers of the
1014 File segments may be relocated to nonstandard addresses, for example by
1015 using the @samp{-Ttext}, @samp{-Tdata}, or @samp{-Tbss} options to
1016 @code{ld}. However, some object file formats, such as a.out, do not
1017 store the starting address of the file segments. In those situations,
1018 although @code{ld} relocates the sections correctly, using @samp{objdump
1019 -h} to list the file section headers cannot show the correct addresses.
1020 Instead, it shows the usual addresses, which are implicit for the
1024 Print a summary of the options to @code{objdump} and exit.
1028 @cindex architectures available
1029 @cindex object formats available
1030 Display a list showing all architectures and object formats available
1031 for specification with @samp{-b} or @samp{-m}.
1034 @itemx --section=@var{name}
1035 @cindex section information
1036 Display information only for section @var{name}.
1039 @itemx --line-numbers
1040 @cindex source filenames for object files
1041 Label the display (using debugging information) with the filename
1042 and source line numbers corresponding to the object code shown.
1043 Only useful with @samp{-d} or @samp{-D}.
1045 @item -m @var{machine}
1046 @itemx --architecture=@var{machine}
1047 @cindex architecture
1048 Specify that the object files @var{objfile} are for architecture
1049 @var{machine}. You can list available architectures using the @samp{-i}
1054 @cindex relocation entries, in object file
1055 Print the relocation entries of the file. If used with @samp{-d} or
1056 @samp{-D}, the relocations are printed interspersed with the
1060 @itemx --dynamic-reloc
1061 @cindex dynamic relocation entries, in object file
1062 Print the dynamic relocation entries of the file. This is only
1063 meaningful for dynamic objects, such as certain types of shared
1067 @itemx --full-contents
1068 @cindex sections, full contents
1069 @cindex object file sections
1070 Display the full contents of any sections requested.
1074 @cindex source disassembly
1075 @cindex disassembly, with source
1076 Display source code intermixed with disassembly, if possible. Implies
1082 @cindex debug symbols
1083 @cindex ELF object file format
1084 Display the full contents of any sections requested. Display the
1085 contents of the .stab and .stab.index and .stab.excl sections from an
1086 ELF file. This is only useful on systems (such as Solaris 2.0) in which
1087 @code{.stab} debugging symbol-table entries are carried in an ELF
1088 section. In most other file formats, debugging symbol-table entries are
1089 interleaved with linkage symbols, and are visible in the @samp{--syms}
1094 @cindex symbol table entries, printing
1095 Print the symbol table entries of the file.
1096 This is similar to the information provided by the @samp{nm} program.
1099 @itemx --dynamic-syms
1100 @cindex dynamic symbol table entries, printing
1101 Print the dynamic symbol table entries of the file. This is only
1102 meaningful for dynamic objects, such as certain types of shared
1103 libraries. This is similar to the information provided by the @samp{nm}
1104 program when given the @samp{-D} (@samp{--dynamic}) option.
1107 Print the version number of @code{objdump} and exit.
1111 @cindex all header information, object file
1112 @cindex header information, all
1113 Display all available header information, including the symbol table and
1114 relocation entries. Using @samp{-x} is equivalent to specifying all of
1115 @samp{-a -f -h -r -t}.
1122 @cindex archive contents
1123 @cindex symbol index
1126 ranlib [-vV] @var{archive}
1129 @code{ranlib} generates an index to the contents of an archive and
1130 stores it in the archive. The index lists each symbol defined by a
1131 member of an archive that is a relocatable object file.
1133 You may use @samp{nm -s} or @samp{nm --print-armap} to list this index.
1135 An archive with such an index speeds up linking to the library and
1136 allows routines in the library to call each other without regard to
1137 their placement in the archive.
1139 The GNU @code{ranlib} program is another form of GNU @code{ar}; running
1140 @code{ranlib} is completely equivalent to executing @samp{ar -s}.
1146 Show the version number of @code{ranlib}.
1153 @cindex section sizes
1156 size [ -A | -B | --format=@var{compatibility} ]
1157 [ --help ] [ -d | -o | -x | --radix=@var{number} ]
1158 [ --target=@var{bfdname} ] [ -V | --version ]
1159 @var{objfile}@dots{}
1162 The GNU @code{size} utility lists the section sizes---and the total
1163 size---for each of the object or archive files @var{objfile} in its
1164 argument list. By default, one line of output is generated for each
1165 object file or each module in an archive.
1167 @var{objfile}@dots{} are the object files to be examined.
1169 The command line options have the following meanings:
1174 @itemx --format=@var{compatibility}
1175 @cindex @code{size} display format
1176 Using one of these options, you can choose whether the output from GNU
1177 @code{size} resembles output from System V @code{size} (using @samp{-A},
1178 or @samp{--format=sysv}), or Berkeley @code{size} (using @samp{-B}, or
1179 @samp{--format=berkeley}). The default is the one-line format similar to
1181 @c Bonus for doc-source readers: you can also say --format=strange (or
1182 @c anything else that starts with 's') for sysv, and --format=boring (or
1183 @c anything else that starts with 'b') for Berkeley.
1185 Here is an example of the Berkeley (default) format of output from
1188 size --format=Berkeley ranlib size
1189 text data bss dec hex filename
1190 294880 81920 11592 388392 5ed28 ranlib
1191 294880 81920 11888 388688 5ee50 size
1195 This is the same data, but displayed closer to System V conventions:
1198 size --format=SysV ranlib size
1216 Show a summary of acceptable arguments and options.
1221 @itemx --radix=@var{number}
1222 @cindex @code{size} number format
1223 @cindex radix for section sizes
1224 Using one of these options, you can control whether the size of each
1225 section is given in decimal (@samp{-d}, or @samp{--radix=10}); octal
1226 (@samp{-o}, or @samp{--radix=8}); or hexadecimal (@samp{-x}, or
1227 @samp{--radix=16}). In @samp{--radix=@var{number}}, only the three
1228 values (8, 10, 16) are supported. The total size is always given in two
1229 radices; decimal and hexadecimal for @samp{-d} or @samp{-x} output, or
1230 octal and hexadecimal if you're using @samp{-o}.
1232 @item --target=@var{bfdname}
1233 @cindex object code format
1234 Specify that the object-code format for @var{objfile} is
1235 @var{bfdname}. This option may not be necessary; @code{size} can
1236 automatically recognize many formats.
1237 @xref{Target Selection}, for more information.
1241 Display the version number of @code{size}.
1247 @cindex listings strings
1248 @cindex printing strings
1249 @cindex strings, printing
1252 strings [-afov] [-@var{min-len}] [-n @var{min-len}] [-t @var{radix}] [-]
1253 [--all] [--print-file-name] [--bytes=@var{min-len}]
1254 [--radix=@var{radix}] [--target=@var{bfdname}]
1255 [--help] [--version] @var{file}@dots{}
1258 For each @var{file} given, GNU @code{strings} prints the printable
1259 character sequences that are at least 4 characters long (or the number
1260 given with the options below) and are followed by a NUL or newline
1261 character. By default, it only prints the strings from the initialized
1262 data sections of object files; for other types of files, it prints the
1263 strings from the whole file.
1265 @code{strings} is mainly useful for determining the contents of non-text
1272 Do not scan only the initialized data section of object files; scan
1276 @itemx --print-file-name
1277 Print the name of the file before each string.
1280 Print a summary of the program usage on the standard output and exit.
1282 @itemx -@var{min-len}
1283 @item -n @var{min-len}
1284 @itemx --bytes=@var{min-len}
1285 Print sequences of characters that are at least @var{min-len} characters
1286 long, instead of the default 4.
1289 Like @samp{-t o}. Some other versions of @code{strings} have @samp{-o}
1290 act like @samp{-t d} instead. Since we can not be compatible with both
1291 ways, we simply chose one.
1293 @item -t @var{radix}
1294 @itemx --radix=@var{radix}
1295 Print the offset within the file before each string. The single
1296 character argument specifies the radix of the offset---@samp{o} for
1297 octal, @samp{x} for hexadecimal, or @samp{d} for decimal.
1299 @item --target=@var{bfdname}
1300 @cindex object code format
1301 Specify an object code format other than your system's default format.
1302 @xref{Target Selection}, for more information.
1306 Print the program version number on the standard output and exit.
1313 @cindex removing symbols
1314 @cindex discarding symbols
1315 @cindex symbols, discarding
1318 strip [ -F @var{bfdname} | --target=@var{bfdname} | --target=@var{bfdname} ]
1319 [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1320 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1321 [ -s | --strip-all ] [ -S | -g | --strip-debug ]
1322 [ -N @var{symbolname} | --strip-symbol=@var{symbolname} ]
1323 [ -x | --discard-all ] [ -X | --discard-locals ]
1324 [ -R @var{sectionname} | --remove-section=@var{sectionname} ]
1325 [ -v | --verbose ] [ -V | --version ] [ --help ]
1326 @var{objfile}@dots{}
1329 GNU @code{strip} discards all symbols from object files
1330 @var{objfile}. The list of object files may include archives.
1331 At least one object file must be given.
1333 @code{strip} modifies the files named in its argument,
1334 rather than writing modified copies under different names.
1337 @item -F @var{bfdname}
1338 @itemx --target=@var{bfdname}
1339 Treat the original @var{objfile} as a file with the object
1340 code format @var{bfdname}, and rewrite it in the same format.
1341 @xref{Target Selection}, for more information.
1344 Show a summary of the options to @code{strip} and exit.
1346 @item -I @var{bfdname}
1347 @itemx --input-target=@var{bfdname}
1348 Treat the original @var{objfile} as a file with the object
1349 code format @var{bfdname}.
1350 @xref{Target Selection}, for more information.
1352 @item -O @var{bfdname}
1353 @itemx --output-target=@var{bfdname}
1354 Replace @var{objfile} with a file in the output format @var{bfdname}.
1355 @xref{Target Selection}, for more information.
1357 @item -R @var{sectionname}
1358 @itemx --remove-section=@var{sectionname}
1359 Remove any section named @var{sectionname} from the output file. This
1360 option may be given more than once. Note that using this option
1361 inappropriately may make the output file unusable.
1369 @itemx --strip-debug
1370 Remove debugging symbols only.
1372 @item -N @var{symbolname}
1373 @itemx --strip-symbol=@var{symbolname}
1374 Remove symbol @var{symbolname} from the source file. This option
1375 may be given more than once, and may be combined with other strip
1379 @itemx --discard-all
1380 Remove non-global symbols.
1383 @itemx --discard-locals
1384 Remove compiler-generated local symbols.
1385 (These usually start with @samp{L} or @samp{.}.)
1389 Show the version number for @code{strip}.
1393 Verbose output: list all object files modified. In the case of
1394 archives, @samp{strip -v} lists all members of the archive.
1401 @cindex demangling C++ symbols
1404 c++filt [ -_ | --strip-underscores ]
1405 [ -n | --no-strip-underscores ]
1406 [ -s @var{format} | --format=@var{format} ]
1407 [ --help ] [ --version ] [ @var{symbol}@dots{} ]
1410 The C++ language provides function overloading, which means that you can
1411 write many functions with the same name (providing each takes parameters
1412 of different types). All C++ function names are encoded into a
1413 low-level assembly label (this process is known as
1414 @dfn{mangling}). The @code{c++filt} program does the inverse mapping: it
1415 decodes (@dfn{demangles}) low-level names into user-level names so that
1416 the linker can keep these overloaded functions from clashing.
1418 Every alphanumeric word (consisting of letters, digits, underscores,
1419 dollars, or periods) seen in the input is a potential label. If the
1420 label decodes into a C++ name, the C++ name replaces the low-level
1423 You can use @code{c++filt} to decipher individual symbols:
1426 c++filt @var{symbol}
1429 If no @var{symbol} arguments are given, @code{c++filt} reads symbol
1430 names from the standard input and writes the demangled names to the
1431 standard output. All results are printed on the standard output.
1435 @itemx --strip-underscores
1436 On some systems, both the C and C++ compilers put an underscore in front
1437 of every name. For example, the C name @code{foo} gets the low-level
1438 name @code{_foo}. This option removes the initial underscore. Whether
1439 @code{c++filt} removes the underscore by default is target dependent.
1442 @itemx --no-strip-underscores
1443 Do not remove the initial underscore.
1445 @item -s @var{format}
1446 @itemx --format=@var{format}
1447 GNU @code{nm} can decode three different methods of mangling, used by
1448 different C++ compilers. The argument to this option selects which
1453 the one used by the GNU compiler (the default method)
1455 the one used by the Lucid compiler
1457 the one specified by the C++ Annotated Reference Manual
1461 Print a summary of the options to @code{c++filt} and exit.
1464 Print the version number of @code{c++filt} and exit.
1468 @emph{Warning:} @code{c++filt} is a new utility, and the details of its
1469 user interface are subject to change in future releases. In particular,
1470 a command-line option may be required in the the future to decode a name
1471 passed as an argument on the command line; in other words,
1474 c++filt @var{symbol}
1478 may in a future release become
1481 c++filt @var{option} @var{symbol}
1488 @code{nlmconv} converts a relocatable object file into a NetWare
1492 @code{nlmconv} currently works with @samp{i386} object
1493 files in @code{coff}, @sc{elf}, or @code{a.out} format, and @sc{SPARC}
1494 object files in @sc{elf}, or @code{a.out} format@footnote{
1495 @code{nlmconv} should work with any @samp{i386} or @sc{sparc} object
1496 format in the Binary File Descriptor library. It has only been tested
1497 with the above formats.}.
1501 @emph{Warning:} @code{nlmconv} is not always built as part of the binary
1502 utilities, since it is only useful for NLM targets.
1506 nlmconv [ -I @var{bfdname} | --input-target=@var{bfdname} ]
1507 [ -O @var{bfdname} | --output-target=@var{bfdname} ]
1508 [ -T @var{headerfile} | --header-file=@var{headerfile} ]
1509 [ -d | --debug] [ -l @var{linker} | --linker=@var{linker} ]
1510 [ -h | --help ] [ -V | --version ]
1511 @var{infile} @var{outfile}
1514 @code{nlmconv} converts the relocatable @samp{i386} object file
1515 @var{infile} into the NetWare Loadable Module @var{outfile}, optionally
1516 reading @var{headerfile} for NLM header information. For instructions
1517 on writing the NLM command file language used in header files, see the
1518 @samp{linkers} section, @samp{NLMLINK} in particular, of the @cite{NLM
1519 Development and Tools Overview}, which is part of the NLM Software
1520 Developer's Kit (``NLM SDK''), available from Novell, Inc.
1521 @code{nlmconv} uses the @sc{gnu} Binary File Descriptor library to read
1522 @var{infile}; see @ref{BFD,,BFD,ld.info,Using LD}, for
1525 @code{nlmconv} can perform a link step. In other words, you can list
1526 more than one object file for input if you list them in the definitions
1527 file (rather than simply specifying one input file on the command line).
1528 In this case, @code{nlmconv} calls the linker for you.
1531 @item -I @var{bfdname}
1532 @itemx --input-target=@var{bfdname}
1533 Object format of the input file. @code{nlmconv} can usually determine
1534 the format of a given file (so no default is necessary).
1535 @xref{Target Selection}, for more information.
1537 @item -O @var{bfdname}
1538 @itemx --output-target=@var{bfdname}
1539 Object format of the output file. @code{nlmconv} infers the output
1540 format based on the input format, e.g. for a @samp{i386} input file the
1541 output format is @samp{nlm32-i386}.
1542 @xref{Target Selection}, for more information.
1544 @item -T @var{headerfile}
1545 @itemx --header-file=@var{headerfile}
1546 Reads @var{headerfile} for NLM header information. For instructions on
1547 writing the NLM command file language used in header files, see@ see the
1548 @samp{linkers} section, of the @cite{NLM Development and Tools
1549 Overview}, which is part of the NLM Software Developer's Kit, available
1554 Displays (on standard error) the linker command line used by @code{nlmconv}.
1556 @item -l @var{linker}
1557 @itemx --linker=@var{linker}
1558 Use @var{linker} for any linking. @var{linker} can be an abosolute or a
1563 Prints a usage summary.
1567 Prints the version number for @code{nlmconv}.
1570 @node Selecting The Target System
1571 @chapter Selecting the target system
1573 You can specify three aspects of the target system to the @sc{gnu}
1574 binary file utilities, each in several ways:
1584 the linker emulation (which applies to the linker only)
1587 In the following summaries, the lists of ways to specify values are in
1588 order of decreasing precedence. The ways listed first override those
1591 The commands to list valid values only list the values for which the
1592 programs you are running were configured. If they were configured with
1593 @samp{--with-targets=all}, the commands list most of the available
1594 values, but a few are left out; not all targets can be configured in at
1595 once because some of them can only be configured @dfn{native} (on hosts
1596 with the same type as the target system).
1599 * Target Selection::
1600 * Architecture Selection::
1601 * Linker Emulation Selection::
1604 @node Target Selection
1605 @section Target Selection
1607 A @dfn{target} is an object file format. A given target may be
1608 supported for multiple architectures (@pxref{Architecture Selection}).
1609 A target selection may also have variations for different operating
1610 systems or architectures.
1612 The command to list valid target values is @samp{objdump -i}
1613 (the first column of output contains the relevant information).
1615 Some sample values are: @samp{a.out-hp300bsd}, @samp{ecoff-littlemips},
1616 @samp{a.out-sunos-big}.
1618 @subheading @code{objdump} Target
1624 command line option: @samp{-b} or @samp{--target}
1627 environment variable @code{GNUTARGET}
1630 deduced from the input file
1633 @subheading @code{objcopy} and @code{strip} Input Target
1639 command line options: @samp{-I} or @samp{--input-target}, or @samp{-F} or @samp{--target}
1642 environment variable @code{GNUTARGET}
1645 deduced from the input file
1648 @subheading @code{objcopy} and @code{strip} Output Target
1654 command line options: @samp{-O} or @samp{--output-target}, or @samp{-F} or @samp{--target}
1657 the input target (see ``@code{objcopy} and @code{strip} Input Target'' above)
1660 environment variable @code{GNUTARGET}
1663 deduced from the input file
1666 @subheading @code{nm}, @code{size}, and @code{strings} Target
1672 command line option: @samp{--target}
1675 environment variable @code{GNUTARGET}
1678 deduced from the input file
1681 @subheading Linker Input Target
1687 command line option: @samp{-b} or @samp{--format}
1688 (@pxref{Options,,Options,ld.info,Using LD})
1691 script command @code{TARGET}
1692 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1695 environment variable @code{GNUTARGET}
1696 (@pxref{Environment,,Environment,ld.info,Using LD})
1699 the default target of the selected linker emulation
1700 (@pxref{Linker Emulation Selection})
1703 @subheading Linker Output Target
1709 command line option: @samp{-oformat}
1710 (@pxref{Options,,Options,ld.info,Using LD})
1713 script command @code{OUTPUT_FORMAT}
1714 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1717 the linker input target (see ``Linker Input Target'' above)
1720 @node Architecture Selection
1721 @section Architecture selection
1723 An @dfn{architecture} is a type of @sc{cpu} on which an object file is
1724 to run. Its name may contain a colon, separating the name of the
1725 processor family from the name of the particular @sc{cpu}.
1727 The command to list valid architecture values is @samp{objdump -i} (the
1728 second column contains the relevant information).
1730 Sample values: @samp{m68k:68020}, @samp{mips:3000}, @samp{sparc}.
1732 @subheading @code{objdump} Architecture
1738 command line option: @samp{-m} or @samp{--architecture}
1741 deduced from the input file
1744 @subheading @code{objcopy}, @code{nm}, @code{size}, @code{strings} Architecture
1750 deduced from the input file
1753 @subheading Linker Input Architecture
1759 deduced from the input file
1762 @subheading Linker Output Architecture
1768 script command @code{OUTPUT_ARCH}
1769 (@pxref{Option Commands,,Option Commands,ld.info,Using LD})
1772 the default architecture from the linker output target
1773 (@pxref{Target Selection})
1776 @node Linker Emulation Selection
1777 @section Linker emulation selection
1779 A linker @dfn{emulation} is a ``personality'' of the linker, which gives
1780 the linker default values for the other aspects of the target system.
1781 In particular, it consists of
1791 several ``hook'' functions that are run at certain stages of the linking
1792 process to do special things that some targets require
1795 The command to list valid linker emulation values is @samp{ld -V}.
1797 Sample values: @samp{hp300bsd}, @samp{mipslit}, @samp{sun4}.
1803 command line option: @samp{-m}
1804 (@pxref{Options,,Options,ld.info,Using LD})
1807 environment variable @code{LDEMULATION}
1810 compiled-in @code{DEFAULT_EMULATION} from @file{Makefile},
1811 which comes from @code{EMUL} in @file{config/@var{target}.mt}