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Updated: July 2014

nm (1g)


nm - list symbols from object files


nm [-a|--debug-syms]
[-g|--extern-only][--plugin name]
[-B] [-C|--demangle[=style]] [-D|--dynamic]
[-S|--print-size] [-s|--print-armap]
[-n|-v|--numeric-sort] [-p|--no-sort]
[-r|--reverse-sort] [--size-sort] [-u|--undefined-only]
[-t radix|--radix=radix] [-P|--portability]
[--target=bfdname] [-fformat|--format=format]
[--defined-only] [-l|--line-numbers] [--no-demangle]
[-V|--version] [-X 32_64] [--help]  [objfile...]


GNU Development Tools                                       NM(1)

     nm - list symbols from object files

     nm [-a|--debug-syms]
        [-g|--extern-only][--plugin name]
        [-B] [-C|--demangle[=style]] [-D|--dynamic]
        [-S|--print-size] [-s|--print-armap]
        [-n|-v|--numeric-sort] [-p|--no-sort]
        [-r|--reverse-sort] [--size-sort] [-u|--undefined-only]
        [-t radix|--radix=radix] [-P|--portability]
        [--target=bfdname] [-fformat|--format=format]
        [--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

     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 usually local; if
         uppercase, the symbol is global (external).  There are
         however a few lowercase symbols that are shown for
         special global symbols ("u", "v" and "w").

         "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

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GNU Development Tools                                       NM(1)

             efficient access to small data objects, such as a
             global int variable as opposed to a large global

         "i" For PE format files this indicates that the symbol
             is in a section specific to the implementation of
             DLLs.  For ELF format files this indicates that the
             symbol is an indirect function.  This is a GNU
             extension to the standard set of ELF symbol types.
             It indicates a symbol which if referenced by a
             relocation does not evaluate to its address, but
             instead must be invoked at runtime.  The runtime
             execution will then return the value to be used in
             the relocation.

         "N" The symbol is a debugging symbol.

         "p" The symbols is in a stack unwind section.

         "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.

         "u" The symbol is a unique global symbol.  This is a GNU
             extension to the standard set of ELF symbol
             bindings.  For such a symbol the dynamic linker will
             make sure that in the entire process there is just
             one symbol with this name and type in use.

         "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.  On some systems, uppercase
             indicates that a default value has been specified.

         "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

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GNU Development Tools                                       NM(1)

             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

         "?" The symbol type is unknown, or object file format

     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

         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

         Do not demangle low-level symbol names.  This is the


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GNU Development Tools                                       NM(1)

         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
         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.

     --plugin name
         Load the plugin called name to add support for extra
         target types.  This option is only available if the
         toolchain has been built with plugin support enabled.

         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 both value and size of defined symbols for the
         "bsd" output style.  This option has no effect for
         object formats that do not record symbol sizes, unless
         --size-sort is also used in which case a calculated size

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GNU Development Tools                                       NM(1)

         is displayed.

         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.

         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 transitions between ARM
         code, THUMB code and data.

     -t radix
         Use radix as the radix for printing the symbol values.
         It must be d for decimal, o for octal, or x for

         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.

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GNU Development Tools                                       NM(1)

     -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.

         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

     See attributes(5) for descriptions of the following

     |Availability   | developer/gnu-binutils |
     |Stability      | Uncommitted            |
     ar(1), objdump(1), ranlib(1), and the Info entries for

     Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997,
     1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
     2008, 2009, 2010, 2011, 2012 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 1.3 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".

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GNU Development Tools                                       NM(1)

     This software was built from source available at  The original
     community source was downloaded from

     Further information about this software can be found on the
     open source community website at

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