nm(1)

Synopsis

   nm [-goxhtnvsnurplCVAPR] files

Description

``Index''

The index of the symbol. (The index appears in brackets.)

``Value''

The value of the symbol is one of the following: a section offset for defined symbols in a relocatable file; alignment constraints for symbols whose section index is ``SHN_COMMON''; a virtual address in executable and dynamic library files.

``Size''

The size in bytes of the associated object.

``Type''

A symbol is of one of the following types: ``NOTYPE'' (no type was specified), ``OBJECT'' (a data object such as an array or variable), ``FUNC'' (a function or other executable code), ``SECTION'' (a section symbol), or ``FILE'' (name of the source file).

``Bind''

The symbol's binding attributes. ``LOCAL'' symbols have a scope limited to the object file containing their definition; ``GLOBAL'' symbols are visible to all object files being combined; and ``WEAK'' symbols are essentially global symbols with a lower precedence than ``GLOBAL''.

``Other''

This field currently indicates the visibility of the symbol. 0 indicates default visibility. ``HIDDEN'' means the symbol is visible solely within the object but not exported to other objects. ``PROT'' means the symbol is "protected." Any reference to the symbol from within the object will go to this definition, even if other definitions are present and would normally take precedence.

``Shndx''

Except for three special values, this is the section header table index in relation to which the symbol is defined. The following special values exist: ``ABS'' indicates the symbol's value will not change through relocation; ``COMMON'' indicates an unallocated block and the value provides alignment constraints; and ``UNDEF'' indicates an undefined symbol.

``Name''

The name of the symbol.

The output of nm may be controlled using the following options:

-g

Only print symbols with binding types GLOBAL and WEAK.

-o

Print the value and size of a symbol in octal instead of decimal.

-x

Print the value and size of a symbol in hexadecimal instead of decimal.

-t d | o | x

Set output format to decimal, octal or hexadecimal. (Decimal is the default; -t o is equivalent to -o; -t x is equivalent to -x)

-h

Do not display the output heading data.

-v

Sort external symbols by value before they are printed.

-s

Print section names instead of section indices.

-n

Sort external symbols by name before they are printed.

-u

Print undefined symbols only.

-r

Prepend the name of the object file or archive to each symbol name. This option is ignored if -P is specified.

-p [-l]

Produce terse output that can be parsed easily. Each symbol name is preceded by its value (blanks if undefined) and one of the letters ``U'' (undefined symbol reference), ``A'' (absolute symbol) ``B'' (symbol defined in .bss or a common symbol) ``N'' (symbol has no type), ``D'' (data object symbol), ``T'' (text symbol), ``S'' (section symbol), or ``F'' (file symbol). If the symbol's binding attribute is ``LOCAL'', the key letter is lower case; if the symbol's binding attribute is ``WEAK'', the key letter is upper case (if the -l modifier is specified, the upper case key letter is followed by an ``*''); if the symbol's binding attribute is ``GLOBAL'', the key letter is upper case.

-C

Print C++ names decoded.

-V

Print on the standard error output the version number of the nm command being executed.

-A

Prepend the name of the object file and archive to each output line.

-P [-l]

Alternate form of terse, easily parseable output (see -p). The symbol name appears first, followed by a keyletter (as described under -p), the symbol's value and its size. The value and size fields are printed in hexadecimal, by default.

-R

Prepend the name of the object file and archive to each symbol name. This option is ignored if -P is specified.

Options may be used in any order, either singly or in combination, and may appear anywhere in the command line. When conflicting options are specified (such as nm -v -n) the first is taken and the second ignored with a warning message to the user.

References