NAME
nm —
display symbolic information in object
files
SYNOPSIS
nm |
[--debug-syms]
[--defined-only]
[--demangle[=style]]
[--dynamic]
[--extern-only] [--help]
[--line-numbers]
[--no-demangle]
[--no-sort]
[--numeric-sort]
[--print-armap]
[--print-file-name]
[--print-size]
[--radix=format]
[--reverse-sort]
[--size-sort]
[--undefined-only]
[--version] [-A]
[-B] [-C
[style]] [-D]
[-P] [-V]
[-a] [-e]
[-g] [-h]
[-l] [-n]
[-o] [-p]
[-r] [-S]
[-s] [-t
format] [-u]
[-x] file ... |
DESCRIPTION
Thenm utility displays symbolic information in the
object files, executables, and object library files named by its arguments.
Lack of symbolic information in an otherwise valid input file, is not
considered to be an error. If no files are specified on the command line,
nm will attempt to read a.out.
The nm utility recognizes the following
options:
--debug-syms- Display all symbols, including debugger-only symbols.
--defined-only- Display only defined symbols.
--demangle[=style]- Decode (demangle) low-level symbol names into human-readable names. Supported values for argument style are ‘auto’, ‘gnu-v2’, ‘gnu-v3’ and ‘arm.’ If argument style is not specified, it is taken to be ‘auto’.
--dynamic- Only display dynamic symbols. This option is only meaningful for shared libraries.
--extern-only- Only display information about global (external) symbols.
--help- Display a help message and exit.
--format=format- Display output in the format specified by argument format. Supported values for the format argument are ‘bsd’, ‘sysv’, and ‘posix’. The default output format is ‘bsd’.
--line-numbers- Display the filename and line number associated a symbol using any debugging information present in the input file. For defined symbols, look up the line number associated with the address of the symbol. For undefined symbols, look up the line number associated with a relocation entry that refers to the symbol. If line number information can be determined, it is displayed after other symbol information.
--no-demangle- Do not demangle symbol names (default).
--no-sort- Do not sort symbols.
--numeric-sort- Sort symbols numerically by address instead of alphabetically by name.
--print-armap- For ar(1) archives, include the index of the archive's members.
--print-file-name- Write the full pathname or library name of an object on each line, before
the rest of the information for a symbol. If this option is not specified,
nmwill only identify an input file once, before its symbols are listed. --print-size- Print the size of each symbol instead of its value.
--radix=radix- Print numeric values using the specified radix. Supported values for argument radix are ‘d’ for decimal, ‘o’ for octal, and ‘x’ for hexadecimal.
--reverse-sort- Reverse the order of the sort.
--size-sort- Sort symbols by size instead of alphabetically by name.
--undefined-only- Display only undefined symbols.
--version- Display the version identifier for
nmand exit. -A- Equivalent to specifying option
--print-file-name. -B- Equivalent to specifying option
--format=bsd. -C[style]- Equivalent to specifying option
--demangle[=style]. -D- Equivalent to specifying option
--dynamic. -Fformat- Equivalent to specifying option
--format=format. -P- Equivalent to specifying option
--format=posix. -S- Equivalent to specifying option
--print-size. -V- Equivalent to specifying option
--version. -a- Equivalent to specifying option
--debug-syms. -e- Only display information for global and static symbols.
-f- Produce full output (default).
-g- Equivalent to specifying option
--extern-only. -h- Equivalent to specifying option
--help. -l- Equivalent to specifying option
--line-numbers. -n- Equivalent to specifying option
--numeric-sort. -o- If POSIX output was specified using the
-Fposix or-Poptions, this option is equivalent to specifying--radix=‘o’. If POSIX output was not specified, this option acts as a synonym for the--print-file-nameoption. -p- Equivalent to specifying option
--no-sort. -v- Equivalent to option
-n. -r- Equivalent to specifying option
--reverse-sort -s- Equivalent to specifying option
--print-armap. -tradix- Equivalent to specifying option
--radix=radix. -u- Equivalent to specifying option
--undefined-only. -x- Write numeric values in hexadecimal (equivalent to -t x).
OUTPUT FORMAT
The nm utility can present its information
in a number of formats, numeric radices and sort orders. By default
nm uses BSD style output, a hexadecimal radix,
without output sorted alphabetically by name and without demangling of
names.
For each symbol listed, nm presents the
following information:
- The library or object name, if options
-Aor--print-file-namewere specified. - The symbol name.
- The type of the symbol denoted by a single character as below:
- A
- A global, absolute symbol.
- B
- A global “bss” (uninitialized data) symbol.
- C
- A “common” symbol, representing uninitialized data.
- D
- A global symbol naming initialized data.
- N
- A debugger symbol.
- R
- A read-only data symbol.
- T
- A global text symbol.
- U
- An undefined symbol.
- V
- A weak object.
- W
- A weak reference.
- a
- A local absolute symbol.
- b
- A local “bss” (uninitialized data) symbol.
- d
- A local data symbol.
- r
- A local read-only data symbol.
- t
- A local text symbol.
- v
- A weak object that is undefined.
- w
- A weak symbol that is undefined.
- ?
- None of the above.
- The value of the symbol.
- The size of the symbol if applicable.
- Line number information, if available and if options
-lor--line-numberswere specified.
EXIT STATUS
The nm utility exits 0 on success,
and >0 if an error occurs.
SEE ALSO
AUTHORS
The nm utility and this manual page were
written by Hyogeol Lee
<hyogeollee@gmail.com>.