<html lang="en"> <head> <title>Input Section Basics - Untitled</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Untitled"> <meta name="generator" content="makeinfo 4.7"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="Input-Section.html#Input-Section" title="Input Section"> <link rel="next" href="Input-Section-Wildcards.html#Input-Section-Wildcards" title="Input Section Wildcards"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- This file documents the GNU linker LD (GNU Binutils) version 2.19. Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc. 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A copy of the license is included in the section entitled ``GNU Free Documentation License''.--> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family: serif; font-weight: normal; } --></style> </head> <body> <div class="node"> <p> <a name="Input-Section-Basics"></a>Next: <a rel="next" accesskey="n" href="Input-Section-Wildcards.html#Input-Section-Wildcards">Input Section Wildcards</a>, Up: <a rel="up" accesskey="u" href="Input-Section.html#Input-Section">Input Section</a> <hr><br> </div> <h5 class="subsubsection">3.6.4.1 Input Section Basics</h5> <p><a name="index-input-section-basics-368"></a>An input section description consists of a file name optionally followed by a list of section names in parentheses. <p>The file name and the section name may be wildcard patterns, which we describe further below (see <a href="Input-Section-Wildcards.html#Input-Section-Wildcards">Input Section Wildcards</a>). <p>The most common input section description is to include all input sections with a particular name in the output section. For example, to include all input <span class="samp">.text</span> sections, you would write: <pre class="smallexample"> *(.text) </pre> <p class="noindent">Here the <span class="samp">*</span> is a wildcard which matches any file name. To exclude a list of files from matching the file name wildcard, EXCLUDE_FILE may be used to match all files except the ones specified in the EXCLUDE_FILE list. For example: <pre class="smallexample"> *(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors) </pre> <p>will cause all .ctors sections from all files except <span class="file">crtend.o</span> and <span class="file">otherfile.o</span> to be included. <p>There are two ways to include more than one section: <pre class="smallexample"> *(.text .rdata) *(.text) *(.rdata) </pre> <p class="noindent">The difference between these is the order in which the <span class="samp">.text</span> and <span class="samp">.rdata</span> input sections will appear in the output section. In the first example, they will be intermingled, appearing in the same order as they are found in the linker input. In the second example, all <span class="samp">.text</span> input sections will appear first, followed by all <span class="samp">.rdata</span> input sections. <p>You can specify a file name to include sections from a particular file. You would do this if one or more of your files contain special data that needs to be at a particular location in memory. For example: <pre class="smallexample"> data.o(.data) </pre> <p>You can also specify files within archives by writing a pattern matching the archive, a colon, then the pattern matching the file, with no whitespace around the colon. <dl> <dt><span class="samp">archive:file</span><dd>matches file within archive <br><dt><span class="samp">archive:</span><dd>matches the whole archive <br><dt><span class="samp">:file</span><dd>matches file but not one in an archive </dl> <p>Either one or both of <span class="samp">archive</span> and <span class="samp">file</span> can contain shell wildcards. On DOS based file systems, the linker will assume that a single letter followed by a colon is a drive specifier, so <span class="samp">c:myfile.o</span> is a simple file specification, not <span class="samp">myfile.o</span> within an archive called <span class="samp">c</span>. <span class="samp">archive:file</span> filespecs may also be used within an <code>EXCLUDE_FILE</code> list, but may not appear in other linker script contexts. For instance, you cannot extract a file from an archive by using <span class="samp">archive:file</span> in an <code>INPUT</code> command. <p>If you use a file name without a list of sections, then all sections in the input file will be included in the output section. This is not commonly done, but it may by useful on occasion. For example: <pre class="smallexample"> data.o </pre> <p>When you use a file name which is not an <span class="samp">archive:file</span> specifier and does not contain any wild card characters, the linker will first see if you also specified the file name on the linker command line or in an <code>INPUT</code> command. If you did not, the linker will attempt to open the file as an input file, as though it appeared on the command line. Note that this differs from an <code>INPUT</code> command, because the linker will not search for the file in the archive search path. </body></html>