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.
-fformat
--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.
-tradix
--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.
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''.
