Something like this:

use strict;
use warnings;
use threads;
use Thread::Queue;

my $workQueue = Thread::Queue->new();
my $doneQueue = Thread::Queue->new();
my @threads;

push @threads, threads->create(sub{DoWork($workQueue, $doneQueue)}) fo
+r 1 .. 4;

for (1 .. 10000) {
    my $work = int(rand(10000));

    $workQueue->enqueue($work);
}

$workQueue->end();
$_->join() for @threads;

print "$_\n" while $doneQueue->pending() && ($_ = $doneQueue->dequeue(
+));
exit;

sub DoWork {
    my ($work, $done) = @_;

    while (my $item = $work->dequeue()) {
        $done->enqueue($item) if $item >= 10 && $item <= 20;
    }
}
[download]

Prints (YMMV):

17
14
11
19
12
10
13
10
11
[download]