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17<title>LD: Output Section Fill</title>
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64<a name="Output-Section-Fill"></a>
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66<p>
67Previous: <a href="Output-Section-Phdr.html#Output-Section-Phdr" accesskey="p" rel="previous">Output Section Phdr</a>, Up: <a href="Output-Section-Attributes.html#Output-Section-Attributes" accesskey="u" rel="up">Output Section Attributes</a> &nbsp; [<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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70<a name="Output-Section-Fill-1"></a>
71<h4 class="subsubsection">3.6.8.8 Output Section Fill</h4>
72<a name="index-_003dfillexp"></a>
73<a name="index-section-fill-pattern"></a>
74<a name="index-fill-pattern_002c-entire-section"></a>
75<p>You can set the fill pattern for an entire section by using
76&lsquo;<samp>=<var>fillexp</var></samp>&rsquo;.  <var>fillexp</var> is an expression
77(see <a href="Expressions.html#Expressions">Expressions</a>).  Any otherwise unspecified regions of memory
78within the output section (for example, gaps left due to the required
79alignment of input sections) will be filled with the value, repeated as
80necessary.  If the fill expression is a simple hex number, ie. a string
81of hex digit starting with &lsquo;<samp>0x</samp>&rsquo; and without a trailing &lsquo;<samp>k</samp>&rsquo; or &lsquo;<samp>M</samp>&rsquo;, then
82an arbitrarily long sequence of hex digits can be used to specify the
83fill pattern;  Leading zeros become part of the pattern too.  For all
84other cases, including extra parentheses or a unary <code>+</code>, the fill
85pattern is the four least significant bytes of the value of the
86expression.  In all cases, the number is big-endian.
87</p>
88<p>You can also change the fill value with a <code>FILL</code> command in the
89output section commands; (see <a href="Output-Section-Data.html#Output-Section-Data">Output Section Data</a>).
90</p>
91<p>Here is a simple example:
92</p><div class="smallexample">
93<pre class="smallexample">SECTIONS { .text : { *(.text) } =0x90909090 }
94</pre></div>
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