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POLogging from output in Perl
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copied!<p>I have a program that is supposed to run a set of other programs and collect their output for logging purposes. Everything is working fine as long as there is output to standard out.</p> <p>That leads me to my two problems:</p> <ol> <li><p>How can I capture both <code>STDIN</code> and <code>STDERR</code> of another program in one file?</p></li> <li><p>If there is no output at all (or output to <code>STDERR</code> only) the program will get stuck on the line:</p> <pre><code>while (<$input>) </code></pre></li> </ol> <p>How can I make the program wait for possible output from another program of indeterminate run time, and still continue if there is no output by the time the program finishes execution.</p> <p>Here is that section of the code</p> <pre><code>my $pid = open (my $input, '-|', "$prog $args") or push @errors, "A failute has occurred in $prog $args"; if(not @errors){ while (<$input>){ #POSSIBLE LOCATION FOR HANG UP IF NO PRINTING IS DONE if($input =~ /^END\n$/){ last; } print $fh $_; } } else{ print $fh "An error has occurred with executing \"$prog $args\""; } </code></pre> <p>note: <code>$fh</code> is my file handler used to write to my log file, and <code>@errors</code> is used for internally reporting errors in my program.</p> <p>EDIT: One problem I experienced with trying the <a href="http://p3rl.org/Proc%3a%3aReliable" rel="nofollow">Proc::Reliable</a> route is that it seems to have after effects on <code>STDOUT</code> and <code>STDERR</code>, and I would need to fix those after each call to run. This leads to another problem in my code. I am running in parallel and any change to <code>STDOUT</code> and <code>STDERR</code> effect all of the threads <em>(using Windows at least)</em>.</p> <p><a href="http://p3rl.org/IO%3a%3aCaptureOutput" rel="nofollow">IO::CaptureOutput</a> has the same issue for me, but it tries to correct the <code>STDOUT</code> and <code>STDERR</code> jumbling internally and causes the following error to occur:</p> <pre class="lang-none prettyprint-override"><code>Couldn't remove temp file 'C:\Users\SBLAKE~1\AppData\Local\Temp\m8E3pUGfOS' - Permission denied at C:/Perl/site/lib/IO/CaptureOutput.pm line 82 </code></pre>

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