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<h2 class="chapter">2 nm</h2>
<p><a name="index-symbols-31"></a><a name="index-nm-32"></a>
<!-- man title nm list symbols from object files -->
<pre class="smallexample"> <!-- man begin SYNOPSIS nm -->
nm [<span class="option">-a</span>|<span class="option">--debug-syms</span>] [<span class="option">-g</span>|<span class="option">--extern-only</span>]
[<span class="option">-B</span>] [<span class="option">-C</span>|<span class="option">--demangle</span>[=<var>style</var>]] [<span class="option">-D</span>|<span class="option">--dynamic</span>]
[<span class="option">-S</span>|<span class="option">--print-size</span>] [<span class="option">-s</span>|<span class="option">--print-armap</span>]
[<span class="option">-A</span>|<span class="option">-o</span>|<span class="option">--print-file-name</span>][<span class="option">--special-syms</span>]
[<span class="option">-n</span>|<span class="option">-v</span>|<span class="option">--numeric-sort</span>] [<span class="option">-p</span>|<span class="option">--no-sort</span>]
[<span class="option">-r</span>|<span class="option">--reverse-sort</span>] [<span class="option">--size-sort</span>] [<span class="option">-u</span>|<span class="option">--undefined-only</span>]
[<span class="option">-t</span> <var>radix</var>|<span class="option">--radix=</span><var>radix</var>] [<span class="option">-P</span>|<span class="option">--portability</span>]
[<span class="option">--target=</span><var>bfdname</var>] [<span class="option">-f</span><var>format</var>|<span class="option">--format=</span><var>format</var>]
[<span class="option">--defined-only</span>] [<span class="option">-l</span>|<span class="option">--line-numbers</span>] [<span class="option">--no-demangle</span>]
[<span class="option">-V</span>|<span class="option">--version</span>] [<span class="option">-X 32_64</span>] [<span class="option">--help</span>] [<var>objfile</var>...]
<!-- man end -->
</pre>
<!-- man begin DESCRIPTION nm -->
<p><span class="sc">gnu</span> <span class="command">nm</span> lists the symbols from object files <var>objfile</var><small class="dots">...</small>.
If no object files are listed as arguments, <span class="command">nm</span> assumes the file
<span class="file">a.out</span>.
<p>For each symbol, <span class="command">nm</span> shows:
<ul>
<li>The symbol value, in the radix selected by options (see below), or
hexadecimal by default.
<li>The symbol type. At least the following types are used; others are, as
well, depending on the object file format. If lowercase, the symbol is
local; if uppercase, the symbol is global (external).
<!-- Some more detail on exactly what these symbol types are used for -->
<!-- would be nice. -->
<dl>
<dt><code>A</code><dd>The symbol's value is absolute, and will not be changed by further
linking.
<br><dt><code>B</code><dt><code>b</code><dd>The symbol is in the uninitialized data section (known as BSS).
<br><dt><code>C</code><dd>The symbol is common. Common symbols are uninitialized data. When
linking, multiple common symbols may appear with the same name. If the
symbol is defined anywhere, the common symbols are treated as undefined
references.
For more details on common symbols, see the discussion of
–warn-common in <a href="../ld/Options.html#Options">Linker options (The GNU linker)</a>.
<br><dt><code>D</code><dt><code>d</code><dd>The symbol is in the initialized data section.
<br><dt><code>G</code><dt><code>g</code><dd>The symbol is in an initialized data section for small objects. Some
object file formats permit more efficient access to small data objects,
such as a global int variable as opposed to a large global array.
<br><dt><code>I</code><dd>The symbol is an indirect reference to another symbol. This is a <span class="sc">gnu</span>
extension to the a.out object file format which is rarely used.
<br><dt><code>i</code><dd>The symbol is in a section specific to the implementation of DLLs.
<br><dt><code>N</code><dd>The symbol is a debugging symbol.
<br><dt><code>p</code><dd>The symbols is in a stack unwind section.
<br><dt><code>R</code><dt><code>r</code><dd>The symbol is in a read only data section.
<br><dt><code>S</code><dt><code>s</code><dd>The symbol is in an uninitialized data section for small objects.
<br><dt><code>T</code><dt><code>t</code><dd>The symbol is in the text (code) section.
<br><dt><code>U</code><dd>The symbol is undefined.
<br><dt><code>V</code><dt><code>v</code><dd>The symbol is a weak object. When a weak defined symbol is linked with
a normal defined symbol, the normal defined symbol is used with no error.
When a weak undefined symbol is linked and the symbol is not defined,
the value of the weak symbol becomes zero with no error. On some
systems, uppercase indicates that a default value has been specified.
<br><dt><code>W</code><dt><code>w</code><dd>The symbol is a weak symbol that has not been specifically tagged as a
weak object symbol. When a weak defined symbol is linked with a normal
defined symbol, the normal defined symbol is used with no error.
When a weak undefined symbol is linked and the symbol is not defined,
the value of the symbol is determined in a system-specific manner without
error. On some systems, uppercase indicates that a default value has been
specified.
<br><dt><code>-</code><dd>The symbol is a stabs symbol in an a.out object file. In this case, the
next values printed are the stabs other field, the stabs desc field, and
the stab type. Stabs symbols are used to hold debugging information.
For more information, see <a href="../stabs/index.html#Top">Stabs (The “stabs” debug format)</a>.
<br><dt><code>?</code><dd>The symbol type is unknown, or object file format specific.
</dl>
<li>The symbol name.
</ul>
<!-- man end -->
<!-- man begin OPTIONS nm -->
<p>The long and short forms of options, shown here as alternatives, are
equivalent.
<dl>
<dt><span class="env">-A</span><dt><span class="env">-o</span><dt><span class="env">--print-file-name</span><dd><a name="index-input-file-name-33"></a><a name="index-file-name-34"></a><a name="index-source-file-name-35"></a>Precede each symbol by the name of the input file (or archive member)
in which it was found, rather than identifying the input file once only,
before all of its symbols.
<br><dt><span class="env">-a</span><dt><span class="env">--debug-syms</span><dd><a name="index-debugging-symbols-36"></a>Display all symbols, even debugger-only symbols; normally these are not
listed.
<br><dt><span class="env">-B</span><dd><a name="index-_0040command_007bnm_007d-format-37"></a><a name="index-_0040command_007bnm_007d-compatibility-38"></a>The same as <span class="option">--format=bsd</span> (for compatibility with the MIPS <span class="command">nm</span>).
<br><dt><span class="env">-C</span><dt><span class="env">--demangle[=</span><var>style</var><span class="env">]</span><dd><a name="index-demangling-in-nm-39"></a>Decode (<dfn>demangle</dfn>) low-level symbol names into user-level names.
Besides removing any initial underscore prepended by the system, this
makes C++ function names readable. Different compilers have different
mangling styles. The optional demangling style argument can be used to
choose an appropriate demangling style for your compiler. See <a href="c_002b_002bfilt.html#c_002b_002bfilt">c++filt</a>,
for more information on demangling.
<br><dt><span class="env">--no-demangle</span><dd>Do not demangle low-level symbol names. This is the default.
<br><dt><span class="env">-D</span><dt><span class="env">--dynamic</span><dd><a name="index-dynamic-symbols-40"></a>Display the dynamic symbols rather than the normal symbols. This is
only meaningful for dynamic objects, such as certain types of shared
libraries.
<br><dt><span class="env">-f </span><var>format</var><dt><span class="env">--format=</span><var>format</var><dd><a name="index-_0040command_007bnm_007d-format-41"></a><a name="index-_0040command_007bnm_007d-compatibility-42"></a>Use the output format <var>format</var>, which can be <code>bsd</code>,
<code>sysv</code>, or <code>posix</code>. The default is <code>bsd</code>.
Only the first character of <var>format</var> is significant; it can be
either upper or lower case.
<br><dt><span class="env">-g</span><dt><span class="env">--extern-only</span><dd><a name="index-external-symbols-43"></a>Display only external symbols.
<br><dt><span class="env">-l</span><dt><span class="env">--line-numbers</span><dd><a name="index-symbol-line-numbers-44"></a>For each symbol, use debugging information to try to find a filename and
line number. For a defined symbol, look for the line number of the
address of the symbol. For an undefined symbol, look for the line
number of a relocation entry which refers to the symbol. If line number
information can be found, print it after the other symbol information.
<br><dt><span class="env">-n</span><dt><span class="env">-v</span><dt><span class="env">--numeric-sort</span><dd>Sort symbols numerically by their addresses, rather than alphabetically
by their names.
<br><dt><span class="env">-p</span><dt><span class="env">--no-sort</span><dd><a name="index-sorting-symbols-45"></a>Do not bother to sort the symbols in any order; print them in the order
encountered.
<br><dt><span class="env">-P</span><dt><span class="env">--portability</span><dd>Use the POSIX.2 standard output format instead of the default format.
Equivalent to <span class="samp">-f posix</span>.
<br><dt><span class="env">-S</span><dt><span class="env">--print-size</span><dd>Print size, not the value, of defined symbols for the <code>bsd</code> output format.
<br><dt><span class="env">-s</span><dt><span class="env">--print-armap</span><dd><a name="index-symbol-index_002c-listing-46"></a>When listing symbols from archive members, include the index: a mapping
(stored in the archive by <span class="command">ar</span> or <span class="command">ranlib</span>) of which modules
contain definitions for which names.
<br><dt><span class="env">-r</span><dt><span class="env">--reverse-sort</span><dd>Reverse the order of the sort (whether numeric or alphabetic); let the
last come first.
<br><dt><span class="env">--size-sort</span><dd>Sort symbols by size. The size is computed as the difference between
the value of the symbol and the value of the symbol with the next higher
value. If the <code>bsd</code> output format is used the size of the symbol
is printed, rather than the value, and <span class="samp">-S</span> must be used in order
both size and value to be printed.
<br><dt><span class="env">--special-syms</span><dd>Display symbols which have a target-specific special meaning. These
symbols are usually used by the target for some special processing and
are not normally helpful when included included in the normal symbol
lists. For example for ARM targets this option would skip the mapping
symbols used to mark transitions between ARM code, THUMB code and
data.
<br><dt><span class="env">-t </span><var>radix</var><dt><span class="env">--radix=</span><var>radix</var><dd>Use <var>radix</var> as the radix for printing the symbol values. It must be
<span class="samp">d</span> for decimal, <span class="samp">o</span> for octal, or <span class="samp">x</span> for hexadecimal.
<br><dt><span class="env">--target=</span><var>bfdname</var><dd><a name="index-object-code-format-47"></a>Specify an object code format other than your system's default format.
See <a href="Target-Selection.html#Target-Selection">Target Selection</a>, for more information.
<br><dt><span class="env">-u</span><dt><span class="env">--undefined-only</span><dd><a name="index-external-symbols-48"></a><a name="index-undefined-symbols-49"></a>Display only undefined symbols (those external to each object file).
<br><dt><span class="env">--defined-only</span><dd><a name="index-external-symbols-50"></a><a name="index-undefined-symbols-51"></a>Display only defined symbols for each object file.
<br><dt><span class="env">-V</span><dt><span class="env">--version</span><dd>Show the version number of <span class="command">nm</span> and exit.
<br><dt><span class="env">-X</span><dd>This option is ignored for compatibility with the AIX version of
<span class="command">nm</span>. It takes one parameter which must be the string
<span class="option">32_64</span>. The default mode of AIX <span class="command">nm</span> corresponds
to <span class="option">-X 32</span>, which is not supported by <span class="sc">gnu</span> <span class="command">nm</span>.
<br><dt><span class="env">--help</span><dd>Show a summary of the options to <span class="command">nm</span> and exit.
</dl>
<!-- man end -->
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