freebsd-dev/nm/nm.1

.\" Copyright (c) 2007 Hyogeol Lee <hyogeollee@gmail.com>
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.\" $Id: nm.1 2377 2012-01-03 07:10:59Z jkoshy $
.\"
.Dd January 3, 2012
.Os
.Dt NM 1
.Sh NAME
.Nm nm
.Nd display symbolic information in object files
.Sh SYNOPSIS
.Nm
.Op Fl -debug-syms
.Op Fl -defined-only
.Op Fl -demangle Ns Op = Ns style
.Op Fl -dynamic
.Op Fl -help
.Op Fl -line-numbers
.Op Fl -no-demangle
.Op Fl -no-sort
.Op Fl -numeric-sort
.Op Fl -print-armap
.Op Fl -print-file-name
.Op Fl -print-size
.Op Fl -radix= Ns Ar format
.Op Fl -reverse-sort
.Op Fl -size-sort
.Op Fl -undefined-only
.Op Fl -version
.Op Fl A
.Op Fl B
.Op Fl C Op Ar style
.Op Fl D
.Op Fl P
.Op Fl V
.Op Fl a
.Op Fl e
.Op Fl g
.Op Fl h
.Op Fl l
.Op Fl n
.Op Fl o
.Op Fl p
.Op Fl r
.Op Fl S
.Op Fl s
.Op Fl t Ar format
.Op Fl u
.Op Fl x
.Ar
.Sh DESCRIPTION
The
.Nm
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
.Pa a.out .
.Pp
The
.Nm
utility recognizes the following options:
.Bl -tag -width ".Fl d Ar argument"
.It Fl -debug-syms
Display all symbols, including debugger-only symbols.
.It Fl -defined-only
Display only defined symbols.
.It Fl -demangle Ns Op = Ns Ar style
Decode (demangle) low-level symbol names into human-readable names.
Supported values for argument
.Ar style
are
.Sq auto ,
.Sq gnu-v2 ,
.Sq gnu-v3
and
.Sq arm.
If argument
.Ar style
is not specified, it is taken to be
.Sq auto .
.It Fl -dynamic
Only display dynamic symbols.
This option is only meaningful for shared libraries.
.It Fl -help
Display a help message and exit.
.It Fl -format Ns = Ns Ar format
Display output in the format specified by argument
.Ar format .
Supported values for the format argument are
.Sq bsd ,
.Sq sysv ,
and
.Sq posix .
The default output format is
.Sq bsd .
.It Fl -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.
.It Fl -no-demangle
Do not demangle symbol names (default).
.It Fl -no-sort
Do not sort symbols.
.It Fl -numeric-sort
Sort symbols numerically by address instead of alphabetically by name.
.It Fl -print-armap
For
.Xr ar 1
archives, include the index of the archive's members.
.It Fl -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,
.Nm
will only identify an input file once, before its symbols are
listed.
.It Fl -print-size
Print the size of each symbol instead of its value.
.It Fl -radix Ns = Ns Ar radix
Print numeric values using the specified radix.
Supported values for argument
.Ar radix
are
.Sq d
for decimal,
.Sq o
for octal, and
.Sq x
for hexadecimal.
.It Fl -reverse-sort
Reverse the order of the sort.
.It Fl -size-sort
Sort symbols by size instead of alphabetically by name.
.It Fl -undefined-only
Display only undefined symbols.
.It Fl -version
Display the version identifier for
.Nm
and exit.
.It Fl A
Equivalent to specifying option
.Fl -print-file-name .
.It Fl B
Equivalent to specifying option
.Fl -format= Ns Ar bsd .
.It Fl C Op Ar style
Equivalent to specifying option
.Fl -demangle Ns Op = Ns Ar style .
.It Fl D
Equivalent to specifying option
.Fl -dynamic .
.It Fl F Ar format
Equivalent to specifying option
.Fl -format Ns = Ns Ar format .
.It Fl P
Equivalent to specifying option
.Fl -format Ns = Ns Ar posix .
.It Fl S
Equivalent to specifying option
.Fl -print-size .
.It Fl V
Equivalent to specifying option
.Fl -version .
.It Fl a
Equivalent to specifying option
.Fl -debug-syms .
.It Fl e
Only display information for global and static symbols.
.It Fl f
Produce full output (default).
.It Fl g
Only display information about global (external) symbols.
.It Fl h
Equivalent to specifying option
.Fl -help .
.It Fl l
Equivalent to specifying option
.Fl -line-numbers .
.It Fl n
Equivalent to specifying option
.Fl -numeric-sort .
.It Fl o
If POSIX output was specified using the
.Fl F Ar posix
or
.Fl P
options, this option is equivalent to specifying
.Fl -radix Ns = Ns Sq Ar o .
If POSIX output was not specified, this option
acts as a synonym for the
.Fl -print-file-name
option.
.It Fl p
Equivalent to specifying option
.Fl -no-sort .
.It Fl v
Equivalent to option
.Fl n .
.It Fl r
Equivalent to specifying option
.Fl -reverse-sort
.It Fl s
Equivalent to specifying option
.Fl -print-armap .
.It Fl t Ar radix
Equivalent to specifying option
.Fl -radix= Ns Ar radix .
.It Fl u
Equivalent to specifying option
.Fl -undefined-only .
.It Fl x
Write numeric values in hexadecimal (equivalent to -t x).
.El
.Sh OUTPUT FORMAT
.Pp
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.
.Pp
For each symbol listed,
.Nm
presents the following information:
.Bl -bullet -compact
.It
The library or object name, if options
.Fl A
or
.Fl -print-file-name
were specified.
.It
The symbol name.
.It
The type of the symbol denoted by a single character as below:
.Bl -tag -compact -width indent
.It A
A global, absolute symbol.
.It B
A global
.Dq bss
(uninitialized data) symbol.
.It C
A
.Dq common
symbol, representing uninitialized data.
.It D
A global symbol naming initialized data.
.It N
A debugger symbol.
.It R
A read-only data symbol.
.It T
A global text symbol.
.It U
An undefined symbol.
.It V
A weak object.
.It W
A weak reference.
.It a
A local absolute symbol.
.It b
A local
.Dq bss
(uninitialized data) symbol.
.It d
A local data symbol.
.It t
A local text symbol.
.It v
A weak object that is undefined.
.It w
A weak symbol that is undefined.
.It ?
None of the above.
.El
.It
The value of the symbol.
.It
The size of the symbol if applicable.
.It
Line number information, if available and if options
.Fl l
or
.Fl -line-numbers
were specified.
.El
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr ar 1 ,
.Xr objdump 1 ,
.Xr ranlib 1 ,
.Xr elf 3
.Sh AUTHORS
The
.Nm
utility and this manual page were written by
.An Hyogeol Lee Aq hyogeollee@gmail.com .