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<h3 class="section">7.32 <code>.file</code></h3>
<p><a name="index-g_t_0040code_007bfile_007d-directive-338"></a>
There are two different versions of the <code>.file</code> directive. Targets
that support DWARF2 line number information use the DWARF2 version of
<code>.file</code>. Other targets use the default version.
<h4 class="subheading">Default Version</h4>
<p><a name="index-logical-file-name-339"></a><a name="index-file-name_002c-logical-340"></a>This version of the <code>.file</code> directive tells <samp><span class="command">as</span></samp> that we
are about to start a new logical file. The syntax is:
<pre class="smallexample"> .file <var>string</var>
</pre>
<p><var>string</var> is the new file name. In general, the filename is
recognized whether or not it is surrounded by quotes ‘<samp><span class="samp">"</span></samp>’; but if you wish
to specify an empty file name, you must give the quotes–<code>""</code>. This
statement may go away in future: it is only recognized to be compatible with
old <samp><span class="command">as</span></samp> programs.
<h4 class="subheading">DWARF2 Version</h4>
<p>When emitting DWARF2 line number information, <code>.file</code> assigns filenames
to the <code>.debug_line</code> file name table. The syntax is:
<pre class="smallexample"> .file <var>fileno</var> <var>filename</var>
</pre>
<p>The <var>fileno</var> operand should be a unique positive integer to use as the
index of the entry in the table. The <var>filename</var> operand is a C string
literal.
<p>The detail of filename indices is exposed to the user because the filename
table is shared with the <code>.debug_info</code> section of the DWARF2 debugging
information, and thus the user must know the exact indices that table
entries will have.
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