nm用法

来源:互联网 发布:ug8.0编程视频教程全集 编辑:程序博客网 时间:2024/03/29 23:03

NM(1)                                                             GNU Development Tools                                                             NM(1)

 

NAME
       nm - list symbols from object files

SYNOPSIS
       nm [-a|--debug-syms] [-g|--extern-only]
          [-B] [-C|--demangle[=style]] [-D|--dynamic]
          [-S|--print-size] [-s|--print-armap]
          [-A|-o|--print-file-name][--special-syms]
          [-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...]

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:

       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 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.

       o   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 signifi-
           cant; 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 defi-
           nitions 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 transistions between ARM code, THUMB code and data.

       -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.

       --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.

COPYRIGHT
       Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005 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-2.16.91.0.5                                                    2008-04-21                                                                  NM(1)
 Manual page nm(1) line 129/193 (END)

原创粉丝点击