NAME
nm - list symbols from object files
SYNOPSIS
nm
[-a|--debug-syms]
[-g|--extern-only]
[-B] [-C|--demangle[=
style]] [-D|--dynamic]
[-S|--print-size] [-s|
--print-armap]
[-A|-o|--print-file-name][
--special-syms]
[-n|-v|--numeric-sort] [
-p|--no-sort]
[-r|--reverse-sort] [--size-sort] [
-u|--undefined-only]
[-t radix|--radix=radix] [
-P|--portability]
[--target=bfdname] [-f
format|--format=format]
[--defined-only] [-l|--line-numbers] [
--no-demangle]
[-V|--version] [-X 32_64] [
--help] [objfile...]
DESCRIPTION
GNU
nm lists the symbols from object files objfile.... If
no object files are listed as arguments, nm assumes the file
a.out.
For each symbol, nm shows:
- *
- The symbol value, in the radix selected by options (see below),
or hexadecimal by default.
- *
- The symbol type. At least the following types are used; others
are, as well, depending on the object file format. If lowercase,
the symbol is local; if uppercase, the symbol is global (external).
-
- A
- The symbol's value is absolute, and will
not be changed by further linking.
- B
- The symbol is in the uninitialized data
section (known as BSS).
- C
- The symbol is common. Common symbols are
uninitialized data. When linking, multiple common symbols may
appear with the same name. If the symbol is defined anywhere, the
common symbols are treated as undefined references.
- D
- The symbol is in the initialized data
section.
- G
- The symbol is in an initialized data
section for small objects. Some object file formats permit more
efficient access to small data objects, such as a global int
variable as opposed to a large global array.
- I
- The symbol is an indirect reference to
another symbol. This is a GNU extension to
the a.out object file format which is rarely used.
- N
- The symbol is a debugging symbol.
- R
- The symbol is in a read only data section.
- S
- The symbol is in an uninitialized data
section for small objects.
- T
- The symbol is in the text (code) section.
- U
- The symbol is undefined.
- V
- The symbol is a weak object. When a weak
defined symbol is linked with a normal defined symbol, the normal
defined symbol is used with no error. When a weak undefined symbol
is linked and the symbol is not defined, the value of the weak
symbol becomes zero with no error.
- W
- The symbol is a weak symbol that has not
been specifically tagged as a weak object symbol. When a weak
defined symbol is linked with a normal defined symbol, the normal
defined symbol is used with no error. When a weak undefined symbol
is linked and the symbol is not defined, the value of the symbol is
determined in a system-specific manner without error. On some
systems, uppercase indicates that a default value has been
specified.
- -
- The symbol is a stabs symbol in an a.out
object file. In this case, the next values printed are the stabs
other field, the stabs desc field, and the stab type. Stabs symbols
are used to hold debugging information.
- ?
- The symbol type is unknown, or object file
format specific.
- *
- The symbol name.
OPTIONS
The long and short forms of
options, shown here as alternatives, are equivalent.
- -A
-
- -o
-
- --print-file-name
- Precede each symbol by the name of the
input file (or archive member) in which it was found, rather than
identifying the input file once only, before all of its symbols.
- -a
-
- --debug-syms
- Display all symbols, even debugger-only
symbols; normally these are not listed.
- -B
- The same as --format=bsd (for
compatibility with the MIPS nm).
- -C
-
- --demangle[=style]
- Decode (demangle) low-level symbol
names into user-level names. Besides removing any initial
underscore prepended by the system, this makes C++ function names readable. Different compilers have
different mangling styles. The optional demangling style argument
can be used to choose an appropriate demangling style for your
compiler.
- --no-demangle
- Do not demangle low-level symbol names.
This is the default.
- -D
-
- --dynamic
- Display the dynamic symbols rather than
the normal symbols. This is only meaningful for dynamic objects,
such as certain types of shared libraries.
- -f format
-
- --format=format
- Use the output format format, which
can be "bsd", "sysv", or "posix". The
default is "bsd". Only the first character of
format is significant; it can be either upper or lower case.
- -g
-
- --extern-only
- Display only external symbols.
- -l
-
- --line-numbers
- For each symbol, use debugging information
to try to find a filename and line number. For a defined symbol,
look for the line number of the address of the symbol. For an
undefined symbol, look for the line number of a relocation entry
which refers to the symbol. If line number information can be
found, print it after the other symbol information.
- -n
-
- -v
-
- --numeric-sort
- Sort symbols numerically by their
addresses, rather than alphabetically by their names.
- -p
-
- --no-sort
- Do not bother to sort the symbols in any
order; print them in the order encountered.
- -P
-
- --portability
- Use the POSIX.2
standard output format instead of the default format. Equivalent to
-f posix.
- -S
-
- --print-size
- Print size, not the value, of defined
symbols for the "bsd" output format.
- -s
-
- --print-armap
- When listing symbols from archive members,
include the index: a mapping (stored in the archive by ar or
ranlib) of which modules contain definitions for which
names.
- -r
-
- --reverse-sort
- Reverse the order of the sort (whether
numeric or alphabetic); let the last come first.
- --size-sort
- Sort symbols by size. The size is computed
as the difference between the value of the symbol and the value of
the symbol with the next higher value. If the "bsd" output
format is used the size of the symbol is printed, rather than the
value, and -S must be used in order both size and value to
be printed.
- --special-syms
- Display symbols which have a
target-specific special meaning. These symbols are usually used by
the target for some special processing and are not normally helpful
when included included in the normal symbol lists. For example for
ARM targets this option would skip the
mapping symbols used to mark transitions between ARM code, THUMB code and data.
- -t radix
-
- --radix=radix
- Use radix as the radix for printing
the symbol values. It must be d for decimal, o for
octal, or x for hexadecimal.
- --target=bfdname
- Specify an object code format other than
your system's default format.
- -u
-
- --undefined-only
- Display only undefined symbols (those
external to each object file).
- --defined-only
- Display only defined symbols for each
object file.
- -V
-
- --version
- Show the version number of nm and
exit.
- -X
- This option is ignored for compatibility
with the AIX version of nm. It takes
one parameter which must be the string 32_64. The default
mode of AIX nm corresponds to -X
32, which is not supported by GNU
nm.
- --help
- Show a summary of the options to nm
and exit.
- @file
- Read command-line options from
file. The options read are inserted in place of the original
@file option. If file does not exist, or cannot be
read, then the option will be treated literally, and not removed.
Options in file are separated by whitespace. A whitespace
character may be included in an option by surrounding the entire
option in either single or double quotes. Any character (including
a backslash) may be included by prefixing the character to be
included with a backslash. The file may itself contain
additional @file options; any such options will be processed
recursively.
SEE ALSO
ar(1),
objdump(1),
ranlib(1),
and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991, 1992,
1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
2004, 2005, 2006 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free
Documentation License, Version 1.1 or any later version published
by the Free Software Foundation; with no Invariant Sections, with
no Front-Cover Texts, and with no Back-Cover Texts. A copy of the
license is included in the section entitled ``GNU Free Documentation License''.