Sending sig INT (control C) to threads

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December 28th, 2006, 04:09 PM

miky

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Sending sig INT (control C) to threads

Hello,
I've seen the documentation of threads with perl and tryed to do what they said to interrupt a thread after Control-C is pressed.
http://search.cpan.org/~jdhedden/threads-1.57/threads.pm#THREAD_SIGNALLING
Unfortunately it makes an error

Code:

#!/usr/bin/perl -w

use strict;
use threads;

sub f1
{
  $SIG{'INT'} = sub { print "Thread exit\n"; threads->exit(); };
  while(1)
  {
    print "SLEEP\n";
    sleep(2);
  }
}

my $thr = threads->new('f1');
$thr->kill('INT')->detach();

Code:

$ ./sigint.pl
Can't locate auto/threads/kill.al in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.8.8 /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl .) at ./new.pl line 19
A thread exited while 2 threads were running.

Strange because I created only one thread not two.

September 7th, 2007, 01:32 PM

BenZarboni

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Ever find a solution for this? I'm stuck on the same thing...

Oh btw, if you spawn a thread, you're going to have two threads: your new thread, and the main thread of execution.

September 7th, 2007, 03:52 PM

Clueless Newbie

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Quote:

Originally Posted by BenZarboni

Ever find a solution for this? I'm stuck on the same thing...

Oh btw, if you spawn a thread, you're going to have two threads: your new thread, and the main thread of execution.

ActiveState 5.8.8 on Win2k

Code:

#!/usr/bin/perl -w

use threads;
use strict;
use lib 'library';
use LOG;
use Smart::Comments;

sub f1 {
  $SIG{INT} = sub {
    ### Thread exit! ...
    threads->exit();
  };
  while(1) {
    ### SLEEPING ...
    sleep(2);
  };
} # f1: well, Monza is SUNDAY

### Starting a thread, dude ...
# AND that "my $thr = threads->new('f1');" is just wrong
my $thr = threads->new(\&f1);
### Wait until the bloody thread has started before you try sending a signal ...
sleep(1);
### Send a signal to the thread ...
$thr->kill('INT');

### Collect the bits and pieces! ...
$_->join foreach threads->list;

__END__

produces

Code:

duh.pl(996) 0 Fri Sep  7 15:49:28 2007 duh.pl(0) << duh.pl >>

duh.pl(996) 0 Fri Sep  7 15:49:28 2007 duh.pl(20) << ### Starting a thread, dude ... >>

duh.pl(996) 0 Fri Sep  7 15:49:28 2007 duh.pl(23) << ### Wait until the bloody thread has started before you try sending a signal ... >>

duh.pl(996) 1 Fri Sep  7 15:49:28 2007 duh.pl(15) << ### SLEEPING ... >>

duh.pl(996) 0 Fri Sep  7 15:49:29 2007 duh.pl(25) << ### Send a signal to the thread ... >>

duh.pl(996) 0 Fri Sep  7 15:49:29 2007 duh.pl(28) << ### Collect the bits and pieces! ... >>

duh.pl(996) 1 Fri Sep  7 15:49:30 2007 duh.pl(11) << ### Thread exit! ... >>

Yes, the number between the (996) and Fri Sep is the thread id!

__________________
"Plagiarize the code of others, I say!"

That's about the worst you can do. It's the fast way to make a very bad coder out of you. It's important to understand what you are doing. Just asking what you should do, and blindly copying that if you would have gotten an unambigious answer is very, very bad.

-- Abigail

September 10th, 2007, 08:21 AM

BenZarboni

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Posts: 104

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Hey;

Thanks for the sample code. Helped me clean some of my stuff up..
The problem for me however lies elsewhere.

In your code or mine, whenever I try to CTRL-C and catch that signal + terminate my threads, I get two problems:

1) The same as the original poster:

$thr->kill('INT'); produces

Quote:

$ ./sigint.pl
Can't locate auto/threads/kill.al in @INC (@INC contains: /etc/perl /usr/local/lib/perl/5.8.8 /usr/local/share/perl/5.8.8 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.8 /usr/share/perl/5.8 /usr/local/lib/site_perl .) at ./new.pl line 19
A thread exited while 2 threads were running.

2) My threads block until they've completed whatever they're doing.. So CTRL-C is blocked until the thread is finished, which prevents me from doing what I want (killing the program immediately)...

hmm..

September 10th, 2007, 08:43 AM

Clueless Newbie

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Post code --- Note that you need to insure that the thread is running and has the SIG handler installed before you attempt the signal ... which is why the sleep 1 in my example.

March 2nd, 2012, 05:35 AM

genaanikev

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Sending sig INT (control C) to threads

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