1NM(1)                        GNU Development Tools                       NM(1)
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NAME

6       nm - list symbols from object files
7

SYNOPSIS

9       nm [-A|-o|--print-file-name] [-a|--debug-syms]
10          [-B|--format=bsd] [-C|--demangle[=style]]
11          [-D|--dynamic] [-fformat|--format=format]
12          [-g|--extern-only] [-h|--help]
13          [-l|--line-numbers] [--inlines]
14          [-n|-v|--numeric-sort]
15          [-P|--portability] [-p|--no-sort]
16          [-r|--reverse-sort] [-S|--print-size]
17          [-s|--print-armap] [-t radix|--radix=radix]
18          [-u|--undefined-only] [-V|--version]
19          [-X 32_64] [--defined-only] [--no-demangle]
20          [--plugin name]
21          [--no-recurse-limit|--recurse-limit]]
22          [--size-sort] [--special-syms]
23          [--synthetic] [--with-symbol-versions] [--target=bfdname]
24          [objfile...]
25

DESCRIPTION

27       GNU nm lists the symbols from object files objfile....  If no object
28       files are listed as arguments, nm assumes the file a.out.
29
30       For each symbol, nm shows:
31
32       ·   The symbol value, in the radix selected by options (see below), or
33           hexadecimal by default.
34
35       ·   The symbol type.  At least the following types are used; others
36           are, as well, depending on the object file format.  If lowercase,
37           the symbol is usually local; if uppercase, the symbol is global
38           (external).  There are however a few lowercase symbols that are
39           shown for special global symbols ("u", "v" and "w").
40
41           "A" The symbol's value is absolute, and will not be changed by
42               further linking.
43
44           "B"
45           "b" The symbol is in the BSS data section.  This section typically
46               contains zero-initialized or uninitialized data, although the
47               exact behavior is system dependent.
48
49           "C" The symbol is common.  Common symbols are uninitialized data.
50               When linking, multiple common symbols may appear with the same
51               name.  If the symbol is defined anywhere, the common symbols
52               are treated as undefined references.
53
54           "D"
55           "d" The symbol is in the initialized data section.
56
57           "G"
58           "g" The symbol is in an initialized data section for small objects.
59               Some object file formats permit more efficient access to small
60               data objects, such as a global int variable as opposed to a
61               large global array.
62
63           "i" For PE format files this indicates that the symbol is in a
64               section specific to the implementation of DLLs.  For ELF format
65               files this indicates that the symbol is an indirect function.
66               This is a GNU extension to the standard set of ELF symbol
67               types.  It indicates a symbol which if referenced by a
68               relocation does not evaluate to its address, but instead must
69               be invoked at runtime.  The runtime execution will then return
70               the value to be used in the relocation.
71
72           "I" The symbol is an indirect reference to another symbol.
73
74           "N" The symbol is a debugging symbol.
75
76           "p" The symbols is in a stack unwind section.
77
78           "R"
79           "r" The symbol is in a read only data section.
80
81           "S"
82           "s" The symbol is in an uninitialized or zero-initialized data
83               section for small objects.
84
85           "T"
86           "t" The symbol is in the text (code) section.
87
88           "U" The symbol is undefined.
89
90           "u" The symbol is a unique global symbol.  This is a GNU extension
91               to the standard set of ELF symbol bindings.  For such a symbol
92               the dynamic linker will make sure that in the entire process
93               there is just one symbol with this name and type in use.
94
95           "V"
96           "v" The symbol is a weak object.  When a weak defined symbol is
97               linked with a normal defined symbol, the normal defined symbol
98               is used with no error.  When a weak undefined symbol is linked
99               and the symbol is not defined, the value of the weak symbol
100               becomes zero with no error.  On some systems, uppercase
101               indicates that a default value has been specified.
102
103           "W"
104           "w" The symbol is a weak symbol that has not been specifically
105               tagged as a weak object symbol.  When a weak defined symbol is
106               linked with a normal defined symbol, the normal defined symbol
107               is used with no error.  When a weak undefined symbol is linked
108               and the symbol is not defined, the value of the symbol is
109               determined in a system-specific manner without error.  On some
110               systems, uppercase indicates that a default value has been
111               specified.
112
113           "-" The symbol is a stabs symbol in an a.out object file.  In this
114               case, the next values printed are the stabs other field, the
115               stabs desc field, and the stab type.  Stabs symbols are used to
116               hold debugging information.
117
118           "?" The symbol type is unknown, or object file format specific.
119
120       ·   The symbol name.
121

OPTIONS

123       The long and short forms of options, shown here as alternatives, are
124       equivalent.
125
126       -A
127       -o
128       --print-file-name
129           Precede each symbol by the name of the input file (or archive
130           member) in which it was found, rather than identifying the input
131           file once only, before all of its symbols.
132
133       -a
134       --debug-syms
135           Display all symbols, even debugger-only symbols; normally these are
136           not listed.
137
138       -B  The same as --format=bsd (for compatibility with the MIPS nm).
139
140       -C
141       --demangle[=style]
142           Decode (demangle) low-level symbol names into user-level names.
143           Besides removing any initial underscore prepended by the system,
144           this makes C++ function names readable. Different compilers have
145           different mangling styles. The optional demangling style argument
146           can be used to choose an appropriate demangling style for your
147           compiler.
148
149       --no-demangle
150           Do not demangle low-level symbol names.  This is the default.
151
152       --recurse-limit
153       --no-recurse-limit
154       --recursion-limit
155       --no-recursion-limit
156           Enables or disables a limit on the amount of recursion performed
157           whilst demangling strings.  Since the name mangling formats allow
158           for an inifinite level of recursion it is possible to create
159           strings whose decoding will exhaust the amount of stack space
160           available on the host machine, triggering a memory fault.  The
161           limit tries to prevent this from happening by restricting recursion
162           to 2048 levels of nesting.
163
164           The default is for this limit to be enabled, but disabling it may
165           be necessary in order to demangle truly complicated names.  Note
166           however that if the recursion limit is disabled then stack
167           exhaustion is possible and any bug reports about such an event will
168           be rejected.
169
170       -D
171       --dynamic
172           Display the dynamic symbols rather than the normal symbols.  This
173           is only meaningful for dynamic objects, such as certain types of
174           shared libraries.
175
176       -f format
177       --format=format
178           Use the output format format, which can be "bsd", "sysv", or
179           "posix".  The default is "bsd".  Only the first character of format
180           is significant; it can be either upper or lower case.
181
182       -g
183       --extern-only
184           Display only external symbols.
185
186       -h
187       --help
188           Show a summary of the options to nm and exit.
189
190       -l
191       --line-numbers
192           For each symbol, use debugging information to try to find a
193           filename and line number.  For a defined symbol, look for the line
194           number of the address of the symbol.  For an undefined symbol, look
195           for the line number of a relocation entry which refers to the
196           symbol.  If line number information can be found, print it after
197           the other symbol information.
198
199       --inlines
200           When option -l is active, if the address belongs to a function that
201           was inlined, then this option causes the source information for all
202           enclosing scopes back to the first non-inlined function to be
203           printed as well.  For example, if "main" inlines "callee1" which
204           inlines "callee2", and address is from "callee2", the source
205           information for "callee1" and "main" will also be printed.
206
207       -n
208       -v
209       --numeric-sort
210           Sort symbols numerically by their addresses, rather than
211           alphabetically by their names.
212
213       -p
214       --no-sort
215           Do not bother to sort the symbols in any order; print them in the
216           order encountered.
217
218       -P
219       --portability
220           Use the POSIX.2 standard output format instead of the default
221           format.  Equivalent to -f posix.
222
223       -r
224       --reverse-sort
225           Reverse the order of the sort (whether numeric or alphabetic); let
226           the last come first.
227
228       -S
229       --print-size
230           Print both value and size of defined symbols for the "bsd" output
231           style.  This option has no effect for object formats that do not
232           record symbol sizes, unless --size-sort is also used in which case
233           a calculated size is displayed.
234
235       -s
236       --print-armap
237           When listing symbols from archive members, include the index: a
238           mapping (stored in the archive by ar or ranlib) of which modules
239           contain definitions for which names.
240
241       -t radix
242       --radix=radix
243           Use radix as the radix for printing the symbol values.  It must be
244           d for decimal, o for octal, or x for hexadecimal.
245
246       -u
247       --undefined-only
248           Display only undefined symbols (those external to each object
249           file).
250
251       -V
252       --version
253           Show the version number of nm and exit.
254
255       -X  This option is ignored for compatibility with the AIX version of
256           nm.  It takes one parameter which must be the string 32_64.  The
257           default mode of AIX nm corresponds to -X 32, which is not supported
258           by GNU nm.
259
260       --defined-only
261           Display only defined symbols for each object file.
262
263       --plugin name
264           Load the plugin called name to add support for extra target types.
265           This option is only available if the toolchain has been built with
266           plugin support enabled.
267
268           If --plugin is not provided, but plugin support has been enabled
269           then nm iterates over the files in ${libdir}/bfd-plugins in
270           alphabetic order and the first plugin that claims the object in
271           question is used.
272
273           Please note that this plugin search directory is not the one used
274           by ld's -plugin option.  In order to make nm use the  linker plugin
275           it must be copied into the ${libdir}/bfd-plugins directory.  For
276           GCC based compilations the linker plugin is called
277           liblto_plugin.so.0.0.0.  For Clang based compilations it is called
278           LLVMgold.so.  The GCC plugin is always backwards compatible with
279           earlier versions, so it is sufficient to just copy the newest one.
280
281       --size-sort
282           Sort symbols by size.  For ELF objects symbol sizes are read from
283           the ELF, for other object types the symbol sizes are computed as
284           the difference between the value of the symbol and the value of the
285           symbol with the next higher value.  If the "bsd" output format is
286           used the size of the symbol is printed, rather than the value, and
287           -S must be used in order both size and value to be printed.
288
289       --special-syms
290           Display symbols which have a target-specific special meaning.
291           These symbols are usually used by the target for some special
292           processing and are not normally helpful when included in the normal
293           symbol lists.  For example for ARM targets this option would skip
294           the mapping symbols used to mark transitions between ARM code,
295           THUMB code and data.
296
297       --synthetic
298           Include synthetic symbols in the output.  These are special symbols
299           created by the linker for various purposes.  They are not shown by
300           default since they are not part of the binary's original source
301           code.
302
303       --with-symbol-versions
304           Enables the display of symbol version information if any exists.
305           The version string is displayed as a suffix to the symbol name,
306           preceeded by an @ character.  For example foo@VER_1.  If the
307           version is the default version to be used when resolving
308           unversioned references to the symbol then it is displayed as a
309           suffix preceeded by two @ characters.  For example foo@@VER_2.
310
311       --target=bfdname
312           Specify an object code format other than your system's default
313           format.
314
315       @file
316           Read command-line options from file.  The options read are inserted
317           in place of the original @file option.  If file does not exist, or
318           cannot be read, then the option will be treated literally, and not
319           removed.
320
321           Options in file are separated by whitespace.  A whitespace
322           character may be included in an option by surrounding the entire
323           option in either single or double quotes.  Any character (including
324           a backslash) may be included by prefixing the character to be
325           included with a backslash.  The file may itself contain additional
326           @file options; any such options will be processed recursively.
327

SEE ALSO

329       ar(1), objdump(1), ranlib(1), and the Info entries for binutils.
330
332       Copyright (c) 1991-2019 Free Software Foundation, Inc.
333
334       Permission is granted to copy, distribute and/or modify this document
335       under the terms of the GNU Free Documentation License, Version 1.3 or
336       any later version published by the Free Software Foundation; with no
337       Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
338       Texts.  A copy of the license is included in the section entitled "GNU
339       Free Documentation License".
340
341
342
343binutils-2.31.90                  2019-01-19                             NM(1)
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