Quite easy.

use forks; 
use Thread::Queue qw( );   # 3.01+

use constant NUM_WORKERS => 10;

sub work {
    my ($client) = @_;
    print("$client start...\n");
    sleep(3 + int(rand(2)));
    print("$client done.\n");
}

{
   my $q = Thread::Queue->new();
   for (1..NUM_WORKERS) {
      async {
         while (my $client = $q->dequeue()) {
            work($client);
         }
      };
   }

   $q->enqueue($_) for 1..33;
   $q->end();
   $_->join() for forks->list();
}
[download]

Can't locate object method "list" via package "forks" at ./threadqueue
+.pl line 33.
Perl exited with active threads:
        10 running and unjoined
        0 finished and unjoined
        0 running and detached
[download]

its threads->list, not forks->list

Yes, and yes. I'm running windows server 2012 with dwimperl.

It sounds like your control program is getting killed by something. I'd recommend opening a shell window and running your control program in that.

Actually I'd recommend running your control program on a Linux machine :)

I was unable to install "forks" eg( use forks) on my windows server 2012 running Dwimperl. So I couldn't test the above code.

The problem I am having is that each of the processes take from 30min to occasionally 2.5 hours to finish, the "wait" seems to be giving up. I can successfully run the first batch of ten, but no method I have tried has ever started the next process when one of the first ten finishes...

Is there a wait time limit var I can adjust? Or is that machine specific?

~~~~~~~~~ I'm unique, just like everybody else! ~~~~~~~~~

Are you running your control program under a webserver? Webservers will time things out on you.

Also, is the control program running on Windows? Fork is faked on Windows.

Please state OS.