nm(CP)

nm -- print name list of an object file

Syntax

nm [-b coff] [-oxhvnefurplCVT] filename...

nm++ [-b coff] [-oxhvnefurplCVT] filename...

Description

The nm(CP) command displays the symbol table of each ELF or COFF object file, filename. filename can be a relocatable or absolute ELF or COFF object file or an archive of relocatable or absolute ELF or COFF object files.

The nm++ command pipes the output of nm through a filter that translates names mangled by C++ to human-readable forms. This makes the output of nm more readable. C names are passed unchanged.

Unless the option -b coff is specified (see ``Notes''), the following information is printed for each symbol in an object file:

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
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

A field reserved for future use, currently containing 0.

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 can be controlled using the following options:

-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.

-h

Do not display the output header data.

-v

Sort external symbols by value before they are printed.

-n

Sort external symbols by name before they are printed.

-e

Print only external and static symbols. The symbol table now contains only static and external symbols. Automatic symbols no longer appear in the symbol table. They do appear in the debugging information produced by cc -g. To examine automatic symbols, use the dump(CP) command.

-f

Produce full output. Redundant symbols (such as .text, .data, and so on) which existed previously do not exist and producing full output will be identical to the default output. This option is obsolete.

-u

Print undefined symbols only.

-r

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

-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 key letters. The case of the key letter is affected by the symbol's binding attribute:

LOCAL: The key letter is lower case.
WEAK: The key letter is upper case (if the -l modifier is specified, the upper case key letter is followed by an *).
GLOBAL: The key letter is upper case.

The key letter is from the set [UNDTSF]:

U: undefined
N: symbol has no type
D: data object symbol
T: text symbol
S: section symbol
F: file symbol

-C

Print C++ names decoded.

-V

Print the version of the nm command executing on the standard error output.

-T

Truncate every name which would otherwise overflow its column and place an asterisk as the last character in the displayed name. By default, nm prints the entire name of the symbols listed. Since symbol names have been moved to the last column, the problem of overflow is removed and it is no longer necessary to truncate the symbol name. This option is obsolete.

When conflicting options are specified (such as nm -v -n) the first is used and the second ignored with a warning message to the user.

Notes

The output format is different from that in previous releases. If all input files are in COFF format, the option -b coff allows you to display the symbol table in the old format. With the option -b coff, the following information is printed for each symbol in a COFF file:

Name: The name of the symbol.
Value: Its value expressed as an offset or an address depending on its storage class.
Class: Its storage class.
Type: Its type and derived type. If the symbol is an instance of a structure or of a union, then the structure or union tag is given following the type (for example, struct-tag). If the symbol is an array, then the array dimensions are given following the type (for example, char[ n ][ m ]).
The object file must have been compiled with the -g option of the cc(CP) command for this information to appear.
Size: Its size in bytes, if available. The object file must have been compiled with the -g option of the cc(CP) command for this information to appear.
Line: The source line number at which it is defined, if available. The object file must have been compiled with the -g option of the cc(CP) command for this information to appear.
Section: For storage classes static and external, the object file section containing the symbol (for example, text, data, or bss).

In addition, the options -e, -f, -p and -T are affected when the option -b coff is used:

-e

Print only external and static symbols.

-f

Produce full output. Redundant symbols (.text, .data, .lib, and .bss) are not suppressed.

-p

Produce terse output that can be parsed easily. Each symbol name is preceded by its value (blanks if undefined) and one of the key letters. If the symbol is local (non-external), the key letter is in lowercase. The key letter is from the set [UABTDSRFC]:

U: undefined
A: absolute
B: .bss symbol
T: text segment symbol
D: data segment symbol
S: user-defined segment symbol
R: register symbol
F: file symbol
C: common symbol

-T

With the option -b coff, nm prints the entire name of the symbols listed. Since object files can have symbol names with an arbitrary number of characters, a name that is longer than the width of the column set aside for names overflows its column, making every column after the name misaligned. The -T option makes nm truncate every name which would otherwise overflow its column and place an asterisk as the last character in the displayed name to mark it as truncated.

Warning

This utility determines whether an object file is in ELF or COFF format and executes the appropriate binaries in each case. Since this utility relies on the files in /usr/ccs/bin/elf and /usr/ccs/bin/coff, changing or moving any of those files results in an error.

Files

TMPDIR/: Temporary files.
TMPDIR is usually /usr/tmp but can be re-defined by setting the environment variable TMPDIR (see tempnam(S) in tmpnam(S)).

Standards conformance

nm is conformant with:

X/Open Portability Guide, Issue 3, 1989 .