use strict;

my $limit = 0.25; # 25% is acceptable slosh for testing timers

    use Time::HiRes qw(setitimer getitimer ITIMER_VIRTUAL);

    my $i = 3;
    my $r = [Time::HiRes::gettimeofday()];

    $SIG{VTALRM} = sub {
        $i ? $i-- : setitimer(&ITIMER_VIRTUAL, 0);
        print "# Tick! $i ", Time::HiRes::tv_interval($r), "\n";
    }; 

    print "# setitimer: ", join(" ", setitimer(ITIMER_VIRTUAL, 0.5, 0.4)), "\n";

    # Assume interval timer granularity of $limit * 0.5 seconds.  Too bold?
    my $virt = getitimer(&ITIMER_VIRTUAL);
    print "not " unless defined $virt && abs($virt / 0.5) - 1 < $limit;
    print "ok 18\n";

    print "# getitimer: ", join(" ", getitimer(ITIMER_VIRTUAL)), "\n";

    while (getitimer(&ITIMER_VIRTUAL)) {
        my $j;
        for (1..1000) { $j++ } # Can't be unbreakable, must test getitimer().
    }

    print "# getitimer: ", join(" ", getitimer(ITIMER_VIRTUAL)), "\n";

    $virt = getitimer(&ITIMER_VIRTUAL);
    print "not " unless defined $virt && $virt == 0;
    print "ok 19\n";

    $SIG{VTALRM} = 'DEFAULT';