nm(1)

NAME

   nm - list symbols from object files

SYNOPSIS

   nm [-A|-o|--print-file-name] [-a|--debug-syms]
      [-B|--format=bsd] [-C|--demangle[=style]]
      [-D|--dynamic] [-fformat|--format=format]
      [-g|--extern-only] [-h|--help]
      [-l|--line-numbers] [-n|-v|--numeric-sort]
      [-P|--portability] [-p|--no-sort]
      [-r|--reverse-sort] [-S|--print-size]
      [-s|--print-armap] [-t radix|--radix=radix]
      [-u|--undefined-only] [-V|--version]
      [-X 32_64] [--defined-only] [--no-demangle]
      [--plugin name] [--size-sort] [--special-syms]
      [--synthetic] [--with-symbol-versions] [--target=bfdname]
      [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 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"
       "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"
       "d" The symbol is in the initialized data section.

       "G"
       "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" 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.

       "I" The symbol is an indirect reference to another symbol.

       "N" The symbol is a debugging symbol.

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

       "R"
       "r" The symbol is in a read only data section.

       "S"
       "s" The symbol is in an uninitialized data section for small
           objects.

       "T"
       "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"
       "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"
       "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.

   -h
   --help
       Show a summary of the options to nm and exit.

   -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.

   -r
   --reverse-sort
       Reverse the order of the sort (whether numeric or alphabetic); let
       the last come first.

   -S
   --print-size
       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 is displayed.

   -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.

   -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.

   -u
   --undefined-only
       Display only undefined symbols (those external to 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.

   --defined-only
       Display only defined symbols for each object file.

   --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.

   --size-sort
       Sort symbols by size.  For ELF objects symbol sizes are read from
       the ELF, for other object types the symbol sizes are 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 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.

   --synthetic
       Include synthetic symbols in the output.  These are special symbols
       created by the linker for various purposes.  They are not shown by
       default since they are not part of the binary's original source
       code.

   --with-symbol-versions
       Enables the display of symbol version information if any exists.
       The version string is displayed as a suffix to the symbol name,
       preceeded by an @ character.  For example foo@VER_1.  If the
       version is the default version to be used when resolving
       unversioned references to the symbol then it is displayed as a
       suffix preceeded by two @ characters.  For example foo@@VER_2.

   --target=bfdname
       Specify an object code format other than your system's default
       format.

   @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) 1991-2016 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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