Re: Newbie user! Anybody can help me?

On Fri, 3 Sep 2004, PerlDiscuss - Perl Newsgroups and mailing lists wrote:

> If the pool is empty the threads stay waiting for new files.

Why not use dequeue(), which is blocking?

> I'm trying to do something like this script below, but the threads can't
> see the queue list.

Do you mean that the worker threads see $DataQueue as perpetually empty, or
what?

At any rate, your example seems to work for me with the following significant
changes, under 5.8.0 (old!):

  - 'threads' instead of 'Thread'
    threads->create(\&threadWorker);     # instead of new Thread ...

  - omit threads::shared
    my $DataQueue = Thread::Queue->new;  # automatically shared

Modified code:

--------------------
#!/usr/bin/perl

use threads;
use Thread::Queue;

my $DataQueue = Thread::Queue->new;

# start threads
threads->create(\&threadWorker, $_) for 1 .. 4;

while (1) {
  $DataQueue->enqueue( my $item = time() );
  print "[producer] Added: $item / Total: ", $DataQueue->pending, "\n";
  sleep 1;
}

sub threadWorker {
  my $WorkerID = shift;
  sleep 5;
  while (1) {
    if ( my $DataElement = $DataQueue->dequeue_nb ) {
      print "[consumer $WorkerID] popped $DataElement\n";
    } else {
      print "[consumer $WorkerID] queue empty [", $DataQueue->pending, "]\n";
    }
    sleep 1;
  }
  return 1;
}
--------------------

Regards,
Mike