nm(1) General Commands Manual nm(1)
nm - name list dump of RISC object files
nm [-adefghnopruvxABTV] [ file1 ... filen ]
The nm command prints listings formats for the symbol and external sections of the symbol table. A file can be an object or an archive.
If you do not specify a file, this command assumes a.out.
The -A and -B options specify AT&T System V style output or Berkeley (4.3 BSD) style output, respectively. The default is Berkeley (4.3
BSD). Some options can change the version-specific defaults. These options change the meaning of overloaded flags after -A or -B is speci-
A normal Berkeley system produces the address or value field followed by a letter showing what section the symbol or external is in and the
name of the symbol or external.
These section letters describe the information that nm generates:
N nil storage class, compiler internal usage
T external text
t local text
D external initialized data
d local initialized data
B external zeroed data
b local zeroed data
A external absolute
a local absolute
U external undefined
G external small initialized data
g local small initialized data
S external small zeroed data
s local small zeroed data
R external read only
r local read only
E small common
V external small undefined
The standard System V format and the -a specified Berkeley format provide an expanded listing with these columns:
Name the symbol or external name
Value the value field for the symbol or external, usually an address or interesting debugging information
Class the symbol type
Type the symbol's language declaration
Index the symbol's index field
Section the symbol's storage class Every effort was made to map the field's functionality into System V nomenclature. The nm command
accepts these options:
-a prints debugging information, effectively turning Berkeley into System V format
-b prints the value field in octal
-d prints the value field in decimal (the System V default)
-e prints external and statics only
-f produces full output--nm still accepts this old option, but ignores it
-h does not print headers
-n for System V, sorts external symbols by name (default for Berkeley), and for Berkeley, sorts all symbols by value
-o for System V, prints the value field in octal, and for Berkeley prepends the filename to each symbol--good for grepping through nm of
-p prints symbols as they are found in the file (the System V default)
-r reverses the sense of a value or name sort
-u prints only undefined symbols
-v sorts external symbols by value
-x prints value field in hexadecimal (Berkeley default)
-T truncates long names, inserting an asterisk (*) as the last printed character
-V prints version information on stderr
Check Out this Related Man Page
NM(1) GNU Development Tools NM(1)
nm - list symbols from object files
nm [-a|--debug-syms] [-g|--extern-only]
[-B] [-C|--demangle[=style]] [-D|--dynamic]
[-r|--reverse-sort] [--size-sort] [-u|--undefined-only]
[-t radix|--radix=radix] [-P|--portability]
[--defined-only] [-l|--line-numbers] [--no-demangle]
[-V|--version] [-X 32_64] [--help] [objfile...]
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:
o The symbol value, in the radix selected by options (see below), or hexadecimal by default.
o 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
"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 sym-
bol 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.
o The symbol name.
The long and short forms of options, shown here as alternatives, are equivalent.
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.
Display all symbols, even debugger-only symbols; normally these are not listed.
-B The same as --format=bsd (for compatibility with the MIPS nm).
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.
Do not demangle low-level symbol names. This is the default.
Display the dynamic symbols rather than the normal symbols. This is only meaningful for dynamic objects, such as certain types of
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.
Display only external symbols.
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.
Sort symbols numerically by their addresses, rather than alphabetically by their names.
Do not bother to sort the symbols in any order; print them in the order encountered.
Use the POSIX.2 standard output format instead of the default format. Equivalent to -f posix.
Print size, not the value, of defined symbols for the "bsd" output format.
When listing symbols from archive members, include the index: a mapping (stored in the archive by ar or ranlib) of which modules con-
tain definitions for which names.
Reverse the order of the sort (whether numeric or alphabetic); let the last come first.
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.
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 transistions between ARM code, THUMB code and data.
Use radix as the radix for printing the symbol values. It must be d for decimal, o for octal, or x for hexadecimal.
Specify an object code format other than your system's default format.
Display only undefined symbols (those external to each object file).
Display only defined symbols for each object file.
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.
Show a summary of the options to nm and exit.
ar(1), objdump(1), ranlib(1), and the Info entries for binutils.
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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''.
binutils-2.15.97 2005-04-20 NM(1)