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POPerl kill(0, $pid) in Windows always returning 1
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  1. POPerl kill(0, $pid) in Windows always returning 1
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    copied!<p>I'm trying to make a Perl script that will run a set of other programs in Windows. I need to be able to capture the stdout, stderr, and exit code of the process, and I need to be able to see if a process exceeds it's allotted execution time. Right now, the pertinent part of my code looks like:</p> <pre><code>... $pid = open3($wtr, $stdout, $stderr, $command); if($time &lt; 0){ waitpid($pid, 0); $return = $? &gt;&gt; 8; $death_sig = $? &amp; 127; $core_dump = $? &amp; 128; } else{ # Do timeout stuff, currently not working as planned print "pid: $pid\n"; my $elapsed = 0; #THIS LOOP ONLY TERMINATES WHEN $time &gt; $elapsed ...? while(kill 0, $pid and $time &gt; $elapsed){ Time::HiRes::usleep(1000); # sleep for milliseconds $elapsed += 1; $return = $? &gt;&gt; 8; $death_sig = $? &amp; 127; $core_dump = $? &amp; 128; } if($elapsed &gt;= $time){ $status = "FAIL"; print $log "TIME LIMIT EXCEEDED\n"; } } #these lines are needed to grab the stdout and stderr in arrays so # I may reuse them in multiple logs if(fileno $stdout){ @stdout = &lt;$stdout&gt;; } if(fileno $stderr){ @stderr = &lt;$stderr&gt;; } ... </code></pre> <p>Everything is working correctly if <code>$time = -1</code> (no timeout is needed), but the system thinks that <code>kill 0, $pid</code> is always 1. This makes my loop run for the entirety of the time allowed.</p> <p>Some extra details just for clarity:</p> <ul> <li>This is being run on Windows.</li> <li>I know my process does terminate because I have get all the expected output.</li> <li>Perl version: This is perl, v5.10.1 built for MSWin32-x86-multi-thread (with 2 registered patches, see perl -V for more detail) Copyright 1987-2009, Larry Wall Binary build 1007 [291969] provided by ActiveState <a href="http://www.ActiveState.com" rel="nofollow">http://www.ActiveState.com</a> Built Jan 26 2010 23:15:11</li> <li>I appreciate your help :D</li> </ul> <p><em>For that future person who may have a similar issue</em> I got the code to work, here is the modified code sections:</p> <pre><code> $pid = open3($wtr, $stdout, $stderr, $command); close($wtr); if($time &lt; 0){ waitpid($pid, 0); } else{ print "pid: $pid\n"; my $elapsed = 0; while(waitpid($pid, WNOHANG) &lt;= 0 and $time &gt; $elapsed){ Time::HiRes::usleep(1000); # sleep for milliseconds $elapsed += 1; } if($elapsed &gt;= $time){ $status = "FAIL"; print $log "TIME LIMIT EXCEEDED\n"; } } $return = $? &gt;&gt; 8; $death_sig = $? &amp; 127; $core_dump = $? &amp; 128; if(fileno $stdout){ @stdout = &lt;$stdout&gt;; } if(fileno $stderr){ @stderr = &lt;$stderr&gt;; } close($stdout); close($stderr); </code></pre>
 

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