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    <p>In all operating systems, you can always abruptly terminate any program. Think of <code>kill -9</code> command in Unix/Linux. You do that on any program, and it stops instantly. No way to trap it. No way for the program to request a few more operating system cycles for a clean up.</p> <p>I'm not up on the difference between Unix and Windows signals, but you can imagine why each OS must allow what we call in Unix <em>SIGKILL</em> - a sure and immediate way to kill any program.</p> <p>Imagine you have a buggy program that intercepts a request to terminate (a SIGTERM in Unix), and it enters a cleanup phase. Instead of cleaning up, the program instead gets stuck in a loop that requests more and more memory. If you couldn't pull the <em>SIGKILL</em> emergency cord, you'd be stuck.</p> <p>The ultimate <em>SIGKILL</em>, of course is the plug in the wall. Pull it, and the program (along with everything else) comes to a screeching halt. There's no way your program can say "<em>Hmm... the power is out and the machines has stopped running... Better start up the old cleanup routine!</em>"</p> <p>So, there's no way you can trap every program termination signal, and, your program will have to account for that. What you can do is see if your program needs to do a cleanup before running. On Windows, you can put an entry in the registry when your program starts up, and remove it when it shuts down and does a cleanup. In Unix, you can put a file or directory name starting wit a period in the <code>$ENV{HOME}</code> directory.</p> <p>Back in the 1980s, I wrote accounting software for a very proprietary OS. When the user pressed the ESCAPE button, we were suppose return immediately to the main menu. If the user was entering an order, and took stuff out of inventory, the transaction would be incomplete, and inventory would be showing the items as being <em>sold</em> even though the order was incomplete. The solution was to check for these incomplete orders the next time someone entered an order, and back out the changes in inventory before entering the new order. Your program may have to do something similar.</p>
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    1. POHow to handle abnormal program termination in Perl on Windows
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    1. COI understand that, but that's not what I was asking. In my original question, I said "excluding events that can't be caught". I know I can't catch the Windows equivalent of SIGKILL or other instantly fatal errors, but I want to be able to catch the equivalent of SIGTERM and similar. But for some reason my signal handler isn't being called except on Ctrl-C. I'd like to learn how to use Windows events directly, rather than going through an incomplete emulation of Unix signals.
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    2. CO@Jonathan - Sorry for the confusion. Perl emulates SIGTERM on Cntrl-C, but otherwise, Windows doesn't use signals that can be captured. You can look at [Win32::Events](http://search.cpan.org/~cjm/Win32-IPC/lib/Win32/Event.pm) which ties into Windows Event Handling. That's what Windows sort of uses instead of signals.
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    3. COThe reference to Win32::Events is helpful, but the documentation only explains how to create and manipulate events. I need to catch whatever event is generated when the process is killed. Can you point me to any information on that? I've googled "catch windows events in perl" and come up with almost nothing.
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