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<a name="Dump-files-and-streams"></a>
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Next: <a href="Dump-output-verbosity.html#Dump-output-verbosity" accesskey="n" rel="next">Dump output verbosity</a>, Previous: <a href="Optimization-groups.html#Optimization-groups" accesskey="p" rel="prev">Optimization groups</a>, Up: <a href="Optimization-info.html#Optimization-info" accesskey="u" rel="up">Optimization info</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Dump-files-and-streams-1"></a>
<h4 class="subsection">9.7.3 Dump files and streams</h4>
<a name="index-optimization-info-file-names"></a>

<p>There are two separate output streams available for outputting
optimization information from passes. Note that both these streams
accept <code>stderr</code> and <code>stdout</code> as valid streams and thus it is
possible to dump output to standard output or error. This is specially
handy for outputting all available information in a single file by
redirecting <code>stderr</code>.
</p>
<dl compact="compact">
<dt><code><code>pstream</code></code></dt>
<dd><p>This stream is for pass-specific dump output. For example,
<samp>-fdump-tree-vect=foo.v</samp> dumps tree vectorization pass output
into the given file name <samp>foo.v</samp>. If the file name is not provided,
the default file name is based on the source file and pass number. Note
that one could also use special file names <code>stdout</code> and
<code>stderr</code> for dumping to standard output and standard error
respectively.
</p>
</dd>
<dt><code><code>alt_stream</code></code></dt>
<dd><p>This steam is used for printing optimization specific output in
response to the <samp>-fopt-info</samp>. Again a file name can be given. If
the file name is not given, it defaults to <code>stderr</code>.
</p></dd>
</dl>


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