#!/usr/bin/perl -w
use strict;
use threads;
use threads::shared;

my $running :shared = 0;

for (my $i = 0; $i < 50; $i++){
    my $thr = threads->create( \&_run_thread, $i );
    $thr->detach;
    sleep 1;
}

sleep 1 while $running;
print "ok.\n";

sub _run_thread {
    { lock $running; ++$running; }
    my ($id) = @_;
    print "starting thread $id ...\n";
    sleep 4;
    print "exiting thread $id.\n";
    { lock $running; --$running; }
    return;
}