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NM(1P)                     POSIX Programmer's Manual                    NM(1P)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface  may  not  be
       implemented on Linux.

NAME
       nm - write the name list of an object file (DEVELOPMENT)

SYNOPSIS
       nm [-APv][-efox][ -g| -u][-t format] file...

DESCRIPTION
       This utility shall be provided on systems that support both the User Portability Utilities option and the Soft-
       ware Development Utilities option. On other systems it is optional. Certain options are only available on  XSI-
       conformant systems.

       The nm utility shall display symbolic information appearing in the object file, executable file, or object-file
       library named by file. If no symbolic information is available for a valid input file,  the  nm  utility  shall
       report that fact, but not consider it an error condition.

       The  default base used when numeric values are written is unspecified.   On XSI-conformant systems, it shall be
       decimal.

OPTIONS
       The nm utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syn-
       tax Guidelines.

       The following options shall be supported:

       -A     Write the full pathname or library name of an object on each line.

       -e     Write only external (global) and static symbol information.

       -f     Produce full output. Write redundant symbols ( .text, .data, and .bss), normally suppressed.

       -g     Write only external (global) symbol information.

       -o     Write numeric values in octal (equivalent to -t o).

       -P     Write information in a portable output format, as specified in the STDOUT section.

       -t  format
              Write  each numeric value in the specified format. The format shall be dependent on the single character
              used as the format option-argument:

       d
              The offset is written in decimal  (default).

       o
              The offset is written in octal.

       x
              The offset is written in hexadecimal.


       -u     Write only undefined symbols.

       -v     Sort output by value instead of alphabetically.

       -x     Write numeric values in hexadecimal (equivalent to -t x).


OPERANDS
       The following operand shall be supported:

       file   A pathname of an object file, executable file, or object-file library.


STDIN
       See the INPUT FILES section.

INPUT FILES
       The input file shall be an object file, an object-file library whose format is the same as  those  produced  by
       the  ar  utility  for link editing, or an executable file. The nm utility may accept additional implementation-
       defined object library formats for the input file.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of nm:

       LANG   Provide a default value for the internationalization variables that are unset or  null.  (See  the  Base
              Definitions  volume  of IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the prece-
              dence of internationalization variables used to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables.

       LC_COLLATE

              Determine  the locale for character collation information for the symbol-name and symbol-value collation
              sequences.

       LC_CTYPE
              Determine the locale for the interpretation of sequences of bytes of text data as characters (for  exam-
              ple, single-byte as opposed to multi-byte characters in arguments).

       LC_MESSAGES
              Determine  the locale that should be used to affect the format and contents of diagnostic messages writ-
              ten to standard error.

       NLSPATH
              Determine the location of message catalogs for the processing of LC_MESSAGES .


ASYNCHRONOUS EVENTS
       Default.

STDOUT
       If symbolic information is present in the input files, then for each file or for each member of an archive, the
       nm  utility  shall  write the following information to standard output.  By default, the format is unspecified,
       but the output shall be sorted alphabetically by symbol name:

        * Library or object name, if -A is specified


        * Symbol name


        * Symbol type, which shall either be one of the following single characters or an implementation-defined  type
          represented by a single character:

       A
              Global absolute symbol.

       a
              Local absolute symbol.

       B
              Global "bss" (that is, uninitialized data space) symbol.

       b
              Local bss symbol.

       D
              Global data symbol.

       d
              Local data symbol.

       T
              Global text symbol.

       t
              Local text symbol.

       U
              Undefined symbol.



        * Value of the symbol


        * The size associated with the symbol, if applicable


       This information may be supplemented by additional information specific to the implementation.

       If the -P option is specified, the previous information shall be displayed using the following portable format.
       The three versions differ depending on whether -t d, -t o, or -t x was specified, respectively:


              "%s%s %s %d %d\n", <library/object name>, <name>, <type>,
                  <value>, <size>


              "%s%s %s %o %o\n", <library/object name>, <name>, <type>,
                  <value>, <size>


              "%s%s %s %x %x\n", <library/object name>, <name>, <type>,
                  <value>, <size>
       where <library/object name> shall be formatted as follows:

        * If -A is not specified, <library/object name> shall be an empty string.


        * If -A is specified and the corresponding file operand does not name a library:


          "%s: ", <file>


        * If -A is specified and the corresponding file operand names a library. In  this  case,  <object file>  shall
          name the object file in the library containing the symbol being described:


          "%s[%s]: ", <file>, <object file>


       If  -A  is not specified, then if more than one file operand is specified or if only one file operand is speci-
       fied and it names a library, nm shall write a line identifying the  object  containing  the  following  symbols
       before the lines containing those symbols, in the form:

        * If the corresponding file operand does not name a library:


          "%s:\n", <file>


        * If the corresponding file operand names a library; in this case, <object file> shall be the name of the file
          in the library containing the following symbols:


          "%s[%s]:\n", <file>, <object file>


       If -P is specified, but -t is not, the format shall be as if -t x had been specified.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0     Successful completion.

       >0     An error occurred.


CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       Mechanisms for dynamic linking make this utility less meaningful when applied to an executable file  because  a
       dynamically  linked  executable  may  omit numerous library routines that would be found in a statically linked
       executable.

EXAMPLES
       None.

RATIONALE
       Historical implementations of nm have used different bases for numeric output and  supplied  different  default
       types  of symbols that were reported. The -t format option, similar to that used in od and strings, can be used
       to specify the numeric base; -g and -u can be used to restrict the amount of output or  the  types  of  symbols
       included in the output.

       The  compromise of using -t format versus using -d, -o, and other similar options was necessary because of dif-
       ferences in the meaning of -o between implementations. The -o option from BSD has been provided here as  -A  to
       avoid  confusion with the -o from System V (which has been provided here as -t and as -o on XSI-conformant sys-
       tems).

       The option list was significantly reduced from that provided by historical implementations.

       The nm description is a subset of both the System V and BSD nm utilities with no specified default output.

       It was recognized that mechanisms for dynamic linking make this utility less meaningful when applied to an exe-
       cutable  file  (because  a  dynamically linked executable file may omit numerous library routines that would be
       found in a statically linked executable file), but the value of nm during software development  was  judged  to
       outweigh other limitations.

       The  default  output format of nm is not specified because of differences in historical implementations. The -P
       option was added to allow some type of portable output format. After a comparison of the different formats used
       in  SunOS,  BSD,  SVR3,  and SVR4, it was decided to create one that did not match the current format of any of
       these four systems. The format devised is easy to parse by humans, easy to parse in shell scripts, and does not
       need  to  vary depending on locale (because no English descriptions are included). All of the systems currently
       have the information available to use this format.

       The format given in nm STDOUT uses spaces between the fields, which may be any number of <blank>s  required  to
       align  the  columns. The single-character types were selected to match historical practice, and the requirement
       that implementation additions also be single characters made parsing the information easier for shell  scripts.

FUTURE DIRECTIONS
       None.

SEE ALSO
       ar, c99

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base  Specifica-
       tions  Issue  6,  Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The
       Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Stan-
       dard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .



IEEE/The Open Group                  2003                               NM(1P)