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			119 lines
		
	
	
	
		
			5.8 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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								<title>Input Section Basics - Untitled</title>
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								<link title="Top" rel="start" href="index.html#Top">
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								<link rel="up" href="Input-Section.html#Input-Section" title="Input Section">
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								<link rel="next" href="Input-Section-Wildcards.html#Input-Section-Wildcards" title="Input Section Wildcards">
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								<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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								<!--
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								This file documents the GNU linker LD
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								(GNU Binutils)
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								version 2.19.
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								Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
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								2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
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								Permission is granted to copy, distribute and/or modify this document
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								under the terms of the GNU Free Documentation License, Version 1.1
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								or any later version published by the Free Software Foundation;
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								with no Invariant Sections, with no Front-Cover Texts, and with no
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								Back-Cover Texts.  A copy of the license is included in the
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								<p>
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								<a name="Input-Section-Basics"></a>Next: <a rel="next" accesskey="n" href="Input-Section-Wildcards.html#Input-Section-Wildcards">Input Section Wildcards</a>,
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								Up: <a rel="up" accesskey="u" href="Input-Section.html#Input-Section">Input Section</a>
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								<hr><br>
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								</div>
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								<h5 class="subsubsection">3.6.4.1 Input Section Basics</h5>
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								<p><a name="index-input-section-basics-368"></a>An input section description consists of a file name optionally followed
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								by a list of section names in parentheses.
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								   <p>The file name and the section name may be wildcard patterns, which we
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								describe further below (see <a href="Input-Section-Wildcards.html#Input-Section-Wildcards">Input Section Wildcards</a>).
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								   <p>The most common input section description is to include all input
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								sections with a particular name in the output section.  For example, to
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								include all input <span class="samp">.text</span> sections, you would write:
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								<pre class="smallexample">     *(.text)
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								</pre>
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								   <p class="noindent">Here the <span class="samp">*</span> is a wildcard which matches any file name.  To exclude a list
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								of files from matching the file name wildcard, EXCLUDE_FILE may be used to
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								match all files except the ones specified in the EXCLUDE_FILE list.  For
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								example:
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								<pre class="smallexample">     *(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors)
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								</pre>
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								   <p>will cause all .ctors sections from all files except <span class="file">crtend.o</span> and
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								<span class="file">otherfile.o</span> to be included.
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								   <p>There are two ways to include more than one section:
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								<pre class="smallexample">     *(.text .rdata)
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								     *(.text) *(.rdata)
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								</pre>
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								   <p class="noindent">The difference between these is the order in which the <span class="samp">.text</span> and
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								<span class="samp">.rdata</span> input sections will appear in the output section.  In the
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								first example, they will be intermingled, appearing in the same order as
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								they are found in the linker input.  In the second example, all
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								<span class="samp">.text</span> input sections will appear first, followed by all
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								<span class="samp">.rdata</span> input sections.
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								   <p>You can specify a file name to include sections from a particular file. 
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								You would do this if one or more of your files contain special data that
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								needs to be at a particular location in memory.  For example:
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								<pre class="smallexample">     data.o(.data)
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								</pre>
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								   <p>You can also specify files within archives by writing a pattern
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								matching the archive, a colon, then the pattern matching the file,
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								with no whitespace around the colon.
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								     <dl>
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								<dt><span class="samp">archive:file</span><dd>matches file within archive
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								<br><dt><span class="samp">archive:</span><dd>matches the whole archive
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								<br><dt><span class="samp">:file</span><dd>matches file but not one in an archive
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								</dl>
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								   <p>Either one or both of <span class="samp">archive</span> and <span class="samp">file</span> can contain shell
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								wildcards.  On DOS based file systems, the linker will assume that a
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								single letter followed by a colon is a drive specifier, so
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								<span class="samp">c:myfile.o</span> is a simple file specification, not <span class="samp">myfile.o</span>
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								within an archive called <span class="samp">c</span>.  <span class="samp">archive:file</span> filespecs may
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								also be used within an <code>EXCLUDE_FILE</code> list, but may not appear in
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								other linker script contexts.  For instance, you cannot extract a file
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								from an archive by using <span class="samp">archive:file</span> in an <code>INPUT</code>
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								command.
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								   <p>If you use a file name without a list of sections, then all sections in
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								the input file will be included in the output section.  This is not
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								commonly done, but it may by useful on occasion.  For example:
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								<pre class="smallexample">     data.o
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								</pre>
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								   <p>When you use a file name which is not an <span class="samp">archive:file</span> specifier
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								and does not contain any wild card
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								characters, the linker will first see if you also specified the file
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								name on the linker command line or in an <code>INPUT</code> command.  If you
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								did not, the linker will attempt to open the file as an input file, as
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								though it appeared on the command line.  Note that this differs from an
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								<code>INPUT</code> command, because the linker will not search for the file in
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								the archive search path.
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								   </body></html>
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