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<h4 class="subsection">9.7.3 Dump files and streams</h4>
<p><a name="index-optimization-info-file-names-1704"></a>
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>.
<dl>
<dt><code>pstream</code><dd>This stream is for pass-specific dump output. For example,
<samp><span class="option">-fdump-tree-vect=foo.v</span></samp> dumps tree vectorization pass output
into the given file name <samp><span class="file">foo.v</span></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.
<br><dt><code>alt_stream</code><dd>This steam is used for printing optimization specific output in
response to the <samp><span class="option">-fopt-info</span></samp>. Again a file name can be given. If
the file name is not given, it defaults to <code>stderr</code>.
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