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<h4 class="subsection">3.4.2 Commands Dealing with Files</h4>
<p><a name="index-linker-script-file-commands-376"></a>Several linker script commands deal with files.
<dl>
<dt><code>INCLUDE </code><var>filename</var><dd><a name="index-INCLUDE-_0040var_007bfilename_007d-377"></a><a name="index-including-a-linker-script-378"></a>Include the linker script <var>filename</var> at this point. The file will
be searched for in the current directory, and in any directory specified
with the <samp><span class="option">-L</span></samp> option. You can nest calls to <code>INCLUDE</code> up to
10 levels deep.
<p>You can place <code>INCLUDE</code> directives at the top level, in <code>MEMORY</code> or
<code>SECTIONS</code> commands, or in output section descriptions.
<br><dt><code>INPUT(</code><var>file</var><code>, </code><var>file</var><code>, ...)</code><dt><code>INPUT(</code><var>file</var> <var>file</var><code> ...)</code><dd><a name="index-INPUT_0028_0040var_007bfiles_007d_0029-379"></a><a name="index-input-files-in-linker-scripts-380"></a><a name="index-input-object-files-in-linker-scripts-381"></a><a name="index-linker-script-input-object-files-382"></a>The <code>INPUT</code> command directs the linker to include the named files
in the link, as though they were named on the command line.
<p>For example, if you always want to include <samp><span class="file">subr.o</span></samp> any time you do
a link, but you can't be bothered to put it on every link command line,
then you can put ‘<samp><span class="samp">INPUT (subr.o)</span></samp>’ in your linker script.
<p>In fact, if you like, you can list all of your input files in the linker
script, and then invoke the linker with nothing but a ‘<samp><span class="samp">-T</span></samp>’ option.
<p>In case a <dfn>sysroot prefix</dfn> is configured, and the filename starts
with the ‘<samp><span class="samp">/</span></samp>’ character, and the script being processed was
located inside the <dfn>sysroot prefix</dfn>, the filename will be looked
for in the <dfn>sysroot prefix</dfn>. Otherwise, the linker will try to
open the file in the current directory. If it is not found, the
linker will search through the archive library search path.
The <dfn>sysroot prefix</dfn> can also be forced by specifying <code>=</code>
as the first character in the filename path. See also the
description of ‘<samp><span class="samp">-L</span></samp>’ in <a href="Options.html#Options">Command Line Options</a>.
<p>If you use ‘<samp><span class="samp">INPUT (-l</span><var>file</var><span class="samp">)</span></samp>’, <samp><span class="command">ld</span></samp> will transform the
name to <code>lib</code><var>file</var><code>.a</code>, as with the command line argument
‘<samp><span class="samp">-l</span></samp>’.
<p>When you use the <code>INPUT</code> command in an implicit linker script, the
files will be included in the link at the point at which the linker
script file is included. This can affect archive searching.
<br><dt><code>GROUP(</code><var>file</var><code>, </code><var>file</var><code>, ...)</code><dt><code>GROUP(</code><var>file</var> <var>file</var><code> ...)</code><dd><a name="index-GROUP_0028_0040var_007bfiles_007d_0029-383"></a><a name="index-grouping-input-files-384"></a>The <code>GROUP</code> command is like <code>INPUT</code>, except that the named
files should all be archives, and they are searched repeatedly until no
new undefined references are created. See the description of ‘<samp><span class="samp">-(</span></samp>’
in <a href="Options.html#Options">Command Line Options</a>.
<br><dt><code>AS_NEEDED(</code><var>file</var><code>, </code><var>file</var><code>, ...)</code><dt><code>AS_NEEDED(</code><var>file</var> <var>file</var><code> ...)</code><dd><a name="index-AS_005fNEEDED_0028_0040var_007bfiles_007d_0029-385"></a>This construct can appear only inside of the <code>INPUT</code> or <code>GROUP</code>
commands, among other filenames. The files listed will be handled
as if they appear directly in the <code>INPUT</code> or <code>GROUP</code> commands,
with the exception of ELF shared libraries, that will be added only
when they are actually needed. This construct essentially enables
<samp><span class="option">--as-needed</span></samp> option for all the files listed inside of it
and restores previous <samp><span class="option">--as-needed</span></samp> resp. <samp><span class="option">--no-as-needed</span></samp>
setting afterwards.
<br><dt><code>OUTPUT(</code><var>filename</var><code>)</code><dd><a name="index-OUTPUT_0028_0040var_007bfilename_007d_0029-386"></a><a name="index-output-file-name-in-linker-script-387"></a>The <code>OUTPUT</code> command names the output file. Using
<code>OUTPUT(</code><var>filename</var><code>)</code> in the linker script is exactly like using
‘<samp><span class="samp">-o </span><var>filename</var></samp>’ on the command line (see <a href="Options.html#Options">Command Line Options</a>). If both are used, the command line option takes
precedence.
<p>You can use the <code>OUTPUT</code> command to define a default name for the
output file other than the usual default of <samp><span class="file">a.out</span></samp>.
<br><dt><code>SEARCH_DIR(</code><var>path</var><code>)</code><dd><a name="index-SEARCH_005fDIR_0028_0040var_007bpath_007d_0029-388"></a><a name="index-library-search-path-in-linker-script-389"></a><a name="index-archive-search-path-in-linker-script-390"></a><a name="index-search-path-in-linker-script-391"></a>The <code>SEARCH_DIR</code> command adds <var>path</var> to the list of paths where
<samp><span class="command">ld</span></samp> looks for archive libraries. Using
<code>SEARCH_DIR(</code><var>path</var><code>)</code> is exactly like using ‘<samp><span class="samp">-L </span><var>path</var></samp>’
on the command line (see <a href="Options.html#Options">Command Line Options</a>). If both
are used, then the linker will search both paths. Paths specified using
the command line option are searched first.
<br><dt><code>STARTUP(</code><var>filename</var><code>)</code><dd><a name="index-STARTUP_0028_0040var_007bfilename_007d_0029-392"></a><a name="index-first-input-file-393"></a>The <code>STARTUP</code> command is just like the <code>INPUT</code> command, except
that <var>filename</var> will become the first input file to be linked, as
though it were specified first on the command line. This may be useful
when using a system in which the entry point is always the start of the
first file.
</dl>
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