#!/usr/local/bin/perl

use threads;
use strict;

# constants
my $workers = 1; #number of simultaneous workers
workerPool();

sub list_threads {
    my @threads = threads->list;
    print "--threads i know of: -----\n";
    for my $t (@threads) {
        print $t->tid."\n";
    }
    print "--------------------------";
}

# sub which maintains a set number of simultaneous threads
sub workerPool {
    print "Starting workerPool...\n";

    my $count = 0;
    my @running_threads = ();
    while (1) {
        @running_threads = threads->list;
        if (scalar(@running_threads) < $workers) {
            # add a new worker
            $count++;
            my $thread = threads->new(\&worker, $count);
        }
        list_threads();
    }
}

# this sub represents a thread
sub worker {
    my $thread_num = $_[0];
    print "---I am thread $thread_num!\n";
    print "+++Thread $thread_num gone!\n";
    eval(((threads->self)->join));
}