NM linux command manual

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]
          [-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 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 (exter-

           "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

           "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

           "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 weak symbol
               becomes zero with no error.

           "-" 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.

       The  long  and short forms of options, shown here as alternatives, are

           Precede each symbol by the name of the input file (or archive mem-
           ber) 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

           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
           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 for-
           mat 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  file-
           name  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 alphabet-
           ically 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 for-
           mat.  Equivalent to -f posix.

           Print size, not the value, of defined symbols for the "bsd" output

           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.

       -t radix
           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

           Display only undefined symbols  (those  external  to  each  object

           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 sup-
           ported 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.

       Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001,  2002,
       2003 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''.

binutils-              2004-05-04                            NM(1)