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CTRL+C Handling in Perl Threads

by anshumangoyal (Scribe)
on Nov 27, 2012 at 09:34 UTC ( #1005824=perlquestion: print w/ replies, xml ) Need Help??
anshumangoyal has asked for the wisdom of the Perl Monks concerning the following question:

I have a program which created 10 different threads. Now, when a user press ctrl+c on this script I have written an interrupt handler in this $SIG{INT} = 'INT_HANDLER' which calls the subroutine 'INT_HANDLER'. But when threads are running, the INterrupt handler is not triggered. Just want to check if Threads have something to do with interrupt handler signals? This is my Program:
use strict; use threads; my @threadsArr; $SIG{INT} = 'INT_HANDLER'; for (my $ii = 0; $ii < 10; $ii++) { my $Thread = threads->new( "Thread_SUB", $arg1, $arg2 ); push (@ThreadsArr, $Thread); } foreach (@ThreadsArr) { $_->join(); } sub INT_HANDLER { print "Received Interrupt, Stopping the Program.\n"; } sub Thread_SUB { my $arg1 = shift; my $arg2 = shift; print "$arg1 - $arg2\n"; sleep 200; }
When this code is executing and Thread_SUB is sleeping and I press CTRL+C, the SIG{INT} is not triggered and thus the Print line in "INT_HANDLER' is not printed.

Comment on CTRL+C Handling in Perl Threads
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Re: CTRL+C Handling in Perl Threads
by remiah (Hermit) on Nov 27, 2012 at 10:09 UTC
      I am using this in Linux/Unix. So Windows is not an issue for me. Can you help me in Unix. Here is my updated sample code:
      use strict; use threads; no warnings 'threads'; our @ThreadsArr; $SIG{INT} = \&INT_HANDLER; $| = 1; sub INT_HANDLER { print "Received Interrupt. Stopping Main Program\n"; } for (my $ii = 0; $ii < 10; $ii++) { my $Thread = threads->new( "Thread_SUB", $ii ); push (@ThreadsArr, $Thread); } foreach (@ThreadsArr) { $_->join(); } sub Thread_SUB { my $thread_id = shift; $SIG{'KILL'} = sub { print "Killing Thread $thread_id\n"; threads->exit(); }; for (my $ii = 0; $ii <= 15; $ii++) { print "$thread_id - Sleeping $ii\n"; sleep 1; } }
      This program is not acknowledging the interrupts when sent as ctrl+c

        I am working on FreeBSD.

        First example showed me SIG_INT message with correcting a few typo. This time also shows me message like

        0 - Sleeping 14
        ^CReceived Interrupt. Stopping Main Program   <==pressed ctrl+c
        
        I wonder why?

        Could you send SIG INT from another terminal? I mean by kill command.

Re: CTRL+C Handling in Perl Threads
by zentara (Archbishop) on Nov 27, 2012 at 10:46 UTC

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