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Re: Calling exit() in thread does not call exit handler

by BrowserUk (Pope)
on Oct 29, 2014 at 16:05 UTC ( #1105498=note: print w/replies, xml ) Need Help??


in reply to Calling exit() in thread does not call exit handler

calling exit() (I know, it is not recommended)

Then don't do that.

If you want to trap an abnormal exit from a thread, use eval & die just like you normally would:

use strict; use threads; use threads::shared; my $inthread : shared; # the exit handler (END block) is never called when a thread performs +an exit() # using a lower main sleep time will result in a normal exit of the ma +in thread. my $threadsleeptime : shared = 2; my $mainsleeptime = 5; my $thread = async { eval { $inthread = 1; sleep($threadsleeptime); print "Sleep in thread finished\n"; die('abnormal exit'); }; if( $@ =~ /^abnormal exit/ ) { ## do cleanup print "doing cleanup in thread\n"; } } sleep($mainsleeptime); print "Sleep in main finished\n"; $thread->join if ($thread); print "End of main program\n"; __END__ C:\test>junk29 Sleep in main finished Sleep in thread finished doing cleanup in thread End of main program

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^2: Calling exit() in thread does not call exit handler
by kees (Initiate) on Oct 30, 2014 at 12:55 UTC
    I don't like to catch an abnormal exit of my thread, but I use a thread to be able to force an exit of the main thread, including cleanup (that belongs to the main thread).

    I know gathered all required information in a shared multi-dimensional hash table, which worked well. It just took some time to solve all invalid scalar errors that happened on runtime (because not all required data was correctly marked as shared).

      I use a thread to be able to force an exit of the main thread

      That is really, really, really bad design -- (*)like designing a train where the only way to get off is to smash a window and jump; and hoping that there'll be somewhere soft to land -- and it will come back to bite you!

      * That's a pretty terrible analogy; maybe this is better: Like designing a satnav such that when you reach your destination, it kills your engine dead and then relies upon the anti-skid brakes and collision avoidance systems to bring you to a halt safely.

      I seriously caution you against taking this design forward. Especially when it is so simple to avoid it:

      use strict; use threads; use threads::shared; my $inthread : shared; sub doCleanUp { print "doing cleanup"; } my $threadsleeptime : shared = 2; my $mainsleeptime = 5; my $thread = async { eval { $inthread = 1; sleep($threadsleeptime); print "Sleep in thread finished\n"; die('abnormal exit'); }; if( $@ =~ /^abnormal exit/ ) { print "triggering cleanup in main\n"; return -1; } return 0; }; $thread->join() and doCleanUp() if ($thread); print "End of main program\n"; __END__ C:\test>junk29 Sleep in thread finished triggering cleanup in main doing cleanupEnd of main program

      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.

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