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| <title>LD: File Commands</title> |
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| <a name="File-Commands"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Format-Commands.html#Format-Commands" accesskey="n" rel="next">Format Commands</a>, Previous: <a href="Entry-Point.html#Entry-Point" accesskey="p" rel="prev">Entry Point</a>, Up: <a href="Simple-Commands.html#Simple-Commands" accesskey="u" rel="up">Simple Commands</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="LD-Index.html#LD-Index" title="Index" rel="index">Index</a>]</p> |
| </div> |
| <hr> |
| <a name="Commands-Dealing-with-Files"></a> |
| <h4 class="subsection">3.4.2 Commands Dealing with Files</h4> |
| <a name="index-linker-script-file-commands"></a> |
| <p>Several linker script commands deal with files. |
| </p> |
| <dl compact="compact"> |
| <dt><code>INCLUDE <var>filename</var></code></dt> |
| <dd><a name="index-INCLUDE-filename"></a> |
| <a name="index-including-a-linker-script"></a> |
| <p>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>-L</samp> option. You can nest calls to <code>INCLUDE</code> up to |
| 10 levels deep. |
| </p> |
| <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. |
| </p> |
| </dd> |
| <dt><code>INPUT(<var>file</var>, <var>file</var>, …)</code></dt> |
| <dt><code>INPUT(<var>file</var> <var>file</var> …)</code></dt> |
| <dd><a name="index-INPUT_0028files_0029"></a> |
| <a name="index-input-files-in-linker-scripts"></a> |
| <a name="index-input-object-files-in-linker-scripts"></a> |
| <a name="index-linker-script-input-object-files"></a> |
| <p>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> |
| <p>For example, if you always want to include <samp>subr.o</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>INPUT (subr.o)</samp>’ in your linker script. |
| </p> |
| <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>-T</samp>’ option. |
| </p> |
| <p>In case a <em>sysroot prefix</em> is configured, and the filename starts |
| with the ‘<samp>/</samp>’ character, and the script being processed was |
| located inside the <em>sysroot prefix</em>, the filename will be looked |
| for in the <em>sysroot prefix</em>. 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 <em>sysroot prefix</em> can also be forced by specifying <code>=</code> |
| as the first character in the filename path. See also the |
| description of ‘<samp>-L</samp>’ in <a href="Options.html#Options">Command Line Options</a>. |
| </p> |
| <p>If you use ‘<samp>INPUT (-l<var>file</var>)</samp>’, <code>ld</code> will transform the |
| name to <code>lib<var>file</var>.a</code>, as with the command line argument |
| ‘<samp>-l</samp>’. |
| </p> |
| <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. |
| </p> |
| </dd> |
| <dt><code>GROUP(<var>file</var>, <var>file</var>, …)</code></dt> |
| <dt><code>GROUP(<var>file</var> <var>file</var> …)</code></dt> |
| <dd><a name="index-GROUP_0028files_0029"></a> |
| <a name="index-grouping-input-files"></a> |
| <p>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>-(</samp>’ |
| in <a href="Options.html#Options">Command Line Options</a>. |
| </p> |
| </dd> |
| <dt><code>AS_NEEDED(<var>file</var>, <var>file</var>, …)</code></dt> |
| <dt><code>AS_NEEDED(<var>file</var> <var>file</var> …)</code></dt> |
| <dd><a name="index-AS_005fNEEDED_0028files_0029"></a> |
| <p>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>--as-needed</samp> option for all the files listed inside of it |
| and restores previous <samp>--as-needed</samp> resp. <samp>--no-as-needed</samp> |
| setting afterwards. |
| </p> |
| </dd> |
| <dt><code>OUTPUT(<var>filename</var>)</code></dt> |
| <dd><a name="index-OUTPUT_0028filename_0029"></a> |
| <a name="index-output-file-name-in-linker-script"></a> |
| <p>The <code>OUTPUT</code> command names the output file. Using |
| <code>OUTPUT(<var>filename</var>)</code> in the linker script is exactly like using |
| ‘<samp>-o <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> |
| <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>a.out</samp>. |
| </p> |
| </dd> |
| <dt><code>SEARCH_DIR(<var>path</var>)</code></dt> |
| <dd><a name="index-SEARCH_005fDIR_0028path_0029"></a> |
| <a name="index-library-search-path-in-linker-script"></a> |
| <a name="index-archive-search-path-in-linker-script"></a> |
| <a name="index-search-path-in-linker-script"></a> |
| <p>The <code>SEARCH_DIR</code> command adds <var>path</var> to the list of paths where |
| <code>ld</code> looks for archive libraries. Using |
| <code>SEARCH_DIR(<var>path</var>)</code> is exactly like using ‘<samp>-L <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. |
| </p> |
| </dd> |
| <dt><code>STARTUP(<var>filename</var>)</code></dt> |
| <dd><a name="index-STARTUP_0028filename_0029"></a> |
| <a name="index-first-input-file"></a> |
| <p>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. |
| </p></dd> |
| </dl> |
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| Next: <a href="Format-Commands.html#Format-Commands" accesskey="n" rel="next">Format Commands</a>, Previous: <a href="Entry-Point.html#Entry-Point" accesskey="p" rel="prev">Entry Point</a>, Up: <a href="Simple-Commands.html#Simple-Commands" accesskey="u" rel="up">Simple Commands</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="LD-Index.html#LD-Index" title="Index" rel="index">Index</a>]</p> |
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