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Re: Need Help With Alarm And Eval

by afoken (Abbot)
on Dec 06, 2012 at 12:12 UTC ( #1007554=note: print w/replies, xml ) Need Help??


in reply to Need Help With Alarm And Eval

The problem is local inside sub On. Perl restores $SIG{'ALRM'} as soon as On returns. You have no other handler for that signal, so the default handler kicks in and kills perl.

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

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Re^2: Need Help With Alarm And Eval
by PerlRocks6345 (Novice) on Dec 06, 2012 at 12:59 UTC

    Hey thanks a lot for your reply removed local and every thing worked perfectly!!!! Thanks a lot!!!!!

      removed local and every thing worked perfectly

      No, it doesn't. The On function sets the signal handler globally, for ever, even after eval has finished. You want local $SIG{'ALRM'} inside that eval.

      The extra subs don't make your code any clearer. I think you should keep alarm and local $SIG{'ALRM'} inside the eval.

      You could also consider writing a generic timeout function like this:

      # untested sub withTimeout { my ($timeout,$worker,$timeouthandler)=@_; eval { local $SIG{'ALRM'}=sub { die "TIMEOUT" }; alarm($timeout); $worker->(); alarm(0); }; if ($@ and $@=~/TIMEOUT/) { $timeouthandler->(); } }

      Alexander

      --
      Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

        Hey Thank you.My problem is ,I want subs to switch on and off my alarm so that i can call them when needed. Any suggestion how to do that ?

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[Corion]: Also see Config::V, which is less of that hackery, or that hackery hidden in a module ;)
[1nickt]: The problem was with Perlbrew
[Corion]: Whoops - Config::Perl::V
[1nickt]: I found that when using Perlbrew as recommended, with cpanminus in the system perl lib, such tests were failing to detect the data about the perl that was the install destination.

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