Content-type: text/html Man page of nm


Section: User Commands (1)
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nm - Name list dump of object files  


nm [-B|-P|-S] [-AabdfhnoprTVvwx] [-e|-g|-u] [-t format] [-mangled_name_only] [-mangled_name_also] [file...]



Interfaces documented on this reference page conform to industry standards as follows:

nm:  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.


The nm command accepts both XPG4-UNIX standard options and DIGITAL extensions.

The following options control the format of the output: Prints output in OSF format. [Compaq]  Prints output in Berkeley (4.3 BSD) format. This format produces an address or value field followed by a letter showing what section the symbol is located in. The third and final field is the name of the symbol. Prints output in a portable (POSIX) format. This format prints lines containing each symbol's name, type (single letter), value, and size. [Compaq]  Prints output in System V format.

The following options control the contents of the output, how sorting is done, and how numeric values are printed. Note that the format that is in effect influences the results of many of these options: Prints the full pathname or library name of an object on each line. [Compaq]  Prints full debugging information. [Compaq]  For Berkeley (-B) format only, prints the value field in octal. Equivalent to -t o. [Compaq]  Prints the value field in decimal. Equivalent to -t d. Prints only external and static symbol information. Prints only external symbol information. [Compaq]  Suppresses the printing of headers. [Compaq]  For Berkeley (-B) format, sorts all symbols by value. For System V (-S) format, sorts external symbols by name. For other formats, sorts all symbols by name. Prints numeric values in octal (equivalent to -t o).

[Compaq]  For Berkeley format (-B), prepends the filename to each symbol (equivalent to -A). [Compaq]  Prints symbols in the order in which they are found in the file. [Compaq]  Reverses the order of a value or name sort. [Compaq]  Truncates long names, inserting an asterisk (*) as the last printed character. Writes each numeric value in the specified format as follows: The offset is written in decimal. Equivalent to -d. The offset is written in octal. Equivalent to -o. The offset is written in hexadecimal. Equivalent to -x. Prints only undefined symbols. [Compaq]  Prints version information on stderr. Sorts output by value instead of alphabetically.
[Compaq]  For System V format (-S), sorts external symbols by value. [Compaq]  Identifies weak symbols using an asterisk (*). For the default, portable (-P), and Berkeley (-B) formats, the asterisk follows the symbol type letter. For System V (-S), an additional column is added to the end of each line containing an asterisk for weak symbols. Prints numeric values in hexadecimal. Equivalent to -t x.

[Compaq]  The DEC C++ compiler encodes type information in function, template, variable, and virtual table names to enable type-safe linkages. This encoding is called ``name mangling.'' The following options can be used to instruct the nm command to print either the original name (that is, the demangled name), the mangled name, or both, by specifying one of the following options. By default, nm shows the demangled names only. [Compaq]  Prints only the mangled name. [Compaq]  Prints both the mangled and the demangled names.


The nm command prints formatted listings of the symbol and external sections of an object file symbol table. A file can be an object file, an archive library, or a shared library. If you do not specify a file, this command assumes a.out.

The nm tool supports four output formats: OSF (the default) [Compaq]  Berkeley 4.3 BSD (-B option) [Compaq]  System V (-S option) Portable (-P option)

The following default behaviors are the same for all four formats: Sort by name Show external and static symbols Output in hexadecimal

The only exception to these defaults is that numbers in OSF format are in decimal by default.

Each format has a distinctive output style and can influence the results of some of the options that affect content, how sorting is done, and how numeric values are printed, as explained in the OPTIONS section.


If symbolic information is present in the input files, nm writes the following information for each file or archive member by default: Symbol name Value of the symbol Symbol type Size associated with the symbol, if applicable

For example:

Name Value Type Size

_gp | 0000005368742016 | A | 0000000000000008 exit | 0000004831842368 | U | 0000000000000008 main | 0000004831842816 | T | 0000000000000008

For the default, portable (-P), and Berkeley (-B) formats, single characters are used as an abbreviation for symbol types. Uppercase characters represent external symbols, and lowercase letters represent local symbols.

The symbol types and their abbreviations are as follows: External absolute Local absolute External zeroed data Local zeroed data [Compaq]  Common External initialized data Local initialized data [Compaq]  Small common [Compaq]  External small initialized data [Compaq]  Local small initialized data [Compaq]  TLS common [Compaq]  TLS initialized data [Compaq]  TLS zeroed data [Compaq]  Nil storage class, compiler internal usage [Compaq]  Read-only constants [Compaq]  Local read-only constants [Compaq]  External read-only data [Compaq]  Local read-only data [Compaq]  External small zeroed data [Compaq]  Local small zeroed data External text Local text External undefined [Compaq]  External small undefined [Compaq]  No storage allocated

[Compaq]  If the -a option is specified, an expanded listing in System V format is written, formatted with the following columns: The symbol or external name Value field for the symbol or external, usually an address or interesting debugging information The symbol type The symbol's declaration The symbol's size The symbol's index field The symbol's storage class


Functions:  ar(1), c89(1)

Standards:  standards(5)

Programmer's Guide, Assembly Language Programmer's Guide




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Time: 02:42:47 GMT, October 02, 2010