1NM(1) GNU Development Tools NM(1)
2
6 nm - list symbols from object files
7
9 nm [-a⎪--debug-syms] [-g⎪--extern-only]
10 [-B] [-C⎪--demangle[=style]] [-D⎪--dynamic]
11 [-S⎪--print-size] [-s⎪--print-armap]
12 [-A⎪-o⎪--print-file-name][--special-syms]
13 [-n⎪-v⎪--numeric-sort] [-p⎪--no-sort]
14 [-r⎪--reverse-sort] [--size-sort] [-u⎪--undefined-only]
15 [-t radix⎪--radix=radix] [-P⎪--portability]
16 [--target=bfdname] [-fformat⎪--format=format]
17 [--defined-only] [-l⎪--line-numbers] [--no-demangle]
18 [-V⎪--version] [-X 32_64] [--help] [objfile...]
19
21 GNU nm lists the symbols from object files objfile.... If no object
22 files are listed as arguments, nm assumes the file a.out.
23 For each symbol, nm shows:
25 · The symbol value, in the radix selected by options (see below), or
27 hexadecimal by default.
28 · The symbol type. At least the following types are used; others
30 are, as well, depending on the object file format. If lowercase,
31 the symbol is local; if uppercase, the symbol is global (external).
32 "A" The symbol's value is absolute, and will not be changed by fur‐
34 ther linking.
35 "B"
37 "b" The symbol is in the uninitialized data section (known as BSS).
38 "C" The symbol is common. Common symbols are uninitialized data.
40 When linking, multiple common symbols may appear with the same
41 name. If the symbol is defined anywhere, the common symbols
42 are treated as undefined references.
43 "D"
45 "d" The symbol is in the initialized data section.
46 "G"
48 "g" The symbol is in an initialized data section for small objects.
49 Some object file formats permit more efficient access to small
50 data objects, such as a global int variable as opposed to a
51 large global array.
52 "I" The symbol is an indirect reference to another symbol. This is
54 a GNU extension to the a.out object file format which is rarely
55 used.
56 "i" The symbol is in a section specific to the implementation of
58 DLLs.
59 "N" The symbol is a debugging symbol.
61 "p" The symbols is in a stack unwind section.
63 "R"
65 "r" The symbol is in a read only data section.
66 "S"
68 "s" The symbol is in an uninitialized data section for small
69 objects.
70 "T"
72 "t" The symbol is in the text (code) section.
73 "U" The symbol is undefined.
75 "V"
77 "v" The symbol is a weak object. When a weak defined symbol is
78 linked with a normal defined symbol, the normal defined symbol
79 is used with no error. When a weak undefined symbol is linked
80 and the symbol is not defined, the value of the weak symbol
81 becomes zero with no error. On some systems, uppercase indi‐
82 cates that a default value has been specified.
83 "W"
85 "w" The symbol is a weak symbol that has not been specifically
86 tagged as a weak object symbol. When a weak defined symbol is
87 linked with a normal defined symbol, the normal defined symbol
88 is used with no error. When a weak undefined symbol is linked
89 and the symbol is not defined, the value of the symbol is
90 determined in a system-specific manner without error. On some
91 systems, uppercase indicates that a default value has been
92 specified.
93 "-" The symbol is a stabs symbol in an a.out object file. In this
95 case, the next values printed are the stabs other field, the
96 stabs desc field, and the stab type. Stabs symbols are used to
97 hold debugging information.
98 "?" The symbol type is unknown, or object file format specific.
100 · The symbol name.
102
104 The long and short forms of options, shown here as alternatives, are
105 equivalent.
106 -A
108 -o
109 --print-file-name
110 Precede each symbol by the name of the input file (or archive mem‐
111 ber) in which it was found, rather than identifying the input file
112 once only, before all of its symbols.
113 -a
115 --debug-syms
116 Display all symbols, even debugger-only symbols; normally these are
117 not listed.
118 -B The same as --format=bsd (for compatibility with the MIPS nm).
120 -C
122 --demangle[=style]
123 Decode (demangle) low-level symbol names into user-level names.
124 Besides removing any initial underscore prepended by the system,
125 this makes C++ function names readable. Different compilers have
126 different mangling styles. The optional demangling style argument
127 can be used to choose an appropriate demangling style for your com‐
128 piler.
129 --no-demangle
131 Do not demangle low-level symbol names. This is the default.
132 -D
134 --dynamic
135 Display the dynamic symbols rather than the normal symbols. This
136 is only meaningful for dynamic objects, such as certain types of
137 shared libraries.
138 -f format
140 --format=format
141 Use the output format format, which can be "bsd", "sysv", or
142 "posix". The default is "bsd". Only the first character of format
143 is significant; it can be either upper or lower case.
144 -g
146 --extern-only
147 Display only external symbols.
148 -l
150 --line-numbers
151 For each symbol, use debugging information to try to find a file‐
152 name and line number. For a defined symbol, look for the line num‐
153 ber of the address of the symbol. For an undefined symbol, look
154 for the line number of a relocation entry which refers to the sym‐
155 bol. If line number information can be found, print it after the
156 other symbol information.
157 -n
159 -v
160 --numeric-sort
161 Sort symbols numerically by their addresses, rather than alphabeti‐
162 cally by their names.
163 -p
165 --no-sort
166 Do not bother to sort the symbols in any order; print them in the
167 order encountered.
168 -P
170 --portability
171 Use the POSIX.2 standard output format instead of the default for‐
172 mat. Equivalent to -f posix.
173 -S
175 --print-size
176 Print size, not the value, of defined symbols for the "bsd" output
177 format.
178 -s
180 --print-armap
181 When listing symbols from archive members, include the index: a
182 mapping (stored in the archive by ar or ranlib) of which modules
183 contain definitions for which names.
184 -r
186 --reverse-sort
187 Reverse the order of the sort (whether numeric or alphabetic); let
188 the last come first.
189 --size-sort
191 Sort symbols by size. The size is computed as the difference
192 between the value of the symbol and the value of the symbol with
193 the next higher value. If the "bsd" output format is used the size
194 of the symbol is printed, rather than the value, and -S must be
195 used in order both size and value to be printed.
196 --special-syms
198 Display symbols which have a target-specific special meaning.
199 These symbols are usually used by the target for some special pro‐
200 cessing and are not normally helpful when included included in the
201 normal symbol lists. For example for ARM targets this option would
202 skip the mapping symbols used to mark transitions between ARM code,
203 THUMB code and data.
204 -t radix
206 --radix=radix
207 Use radix as the radix for printing the symbol values. It must be
208 d for decimal, o for octal, or x for hexadecimal.
209 --target=bfdname
211 Specify an object code format other than your system's default for‐
212 mat.
213 -u
215 --undefined-only
216 Display only undefined symbols (those external to each object
217 file).
218 --defined-only
220 Display only defined symbols for each object file.
221 -V
223 --version
224 Show the version number of nm and exit.
225 -X This option is ignored for compatibility with the AIX version of
227 nm. It takes one parameter which must be the string 32_64. The
228 default mode of AIX nm corresponds to -X 32, which is not supported
229 by GNU nm.
230 --help
232 Show a summary of the options to nm and exit.
233 @file
235 Read command-line options from file. The options read are inserted
236 in place of the original @file option. If file does not exist, or
237 cannot be read, then the option will be treated literally, and not
238 removed.
239 Options in file are separated by whitespace. A whitespace charac‐
241 ter may be included in an option by surrounding the entire option
242 in either single or double quotes. Any character (including a
243 backslash) may be included by prefixing the character to be
244 included with a backslash. The file may itself contain additional
245 @file options; any such options will be processed recursively.
246
248 ar(1), objdump(1), ranlib(1), and the Info entries for binutils.
249
251 Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
252 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software
253 Foundation, Inc.
254 Permission is granted to copy, distribute and/or modify this document
256 under the terms of the GNU Free Documentation License, Version 1.2 or
257 any later version published by the Free Software Foundation; with no
258 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
259 Texts. A copy of the license is included in the section entitled "GNU
260 Free Documentation License".
261binutils-2.18.90 2008-09-10 NM(1)