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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;
}

[download]
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 (Friar) on Nov 27, 2012 at 10:09 UTC
[reply]
      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;
    }
}


      [download]
      This program is not acknowledging the interrupts when sent as ctrl+c
[reply]
[d/l]

        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.

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

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