Perl threads kill timeout thread

Question

I have a multi-thread perl script using threads, works ok but when it tries to kill the hanged threads I got an error and script exists:

for (0..$threads-1) {
        $trl[$_] = threads->create(\&my_sub, $_);
        $SIG{ALRM} = sub {
                if ($trl->is_running) {
                   $trl->kill('ALRM');
                }
        }
}
for (@trl) {
        alarm 10;
        $_->join;
}

and

sub my_sub {
  $SIG{ALRM} = sub {
        threads->exit(1);
  };
  while (@site) {
  {
        lock(@site);
        $url = shift @site;
  }

and the error:

Can't call method "is_running" on an undefined value at test.pl line 61.
Perl exited with active threads:
        9 running and unjoined
        40 finished and unjoined
        0 running and detached

the line 61 is:

if ($trl->is_running) {

Sobrique Sobrique · Accepted Answer · 2015-08-07T13:01:06

OK, please turn on strict and warnings. This would tell you that @trl and $trl are not the same thing. Specifically - your 'signal handler' in your main program - you're redefining every time you start a thread, and so it'll only kill the latest one. (Except it won't, because $tr1 is undefined).

I would suggest you don't want to mix signals and threads anyway though - this depends rather more on what you're doing. But usually I'd suggest - fork and kill. thread and Thread::Semaphore or Thread::Queue.

Perl threads kill timeout thread

1 Answers