use Time::HiRes qw( sleep );

my $pid = fork();
die $! if !defined($pid);

if ($pid == 0) {
    for (1..2) {
        kill TTOU => 0
            or die $!
            if $_ != 1;
        for (1..4) {
            sleep(.250) if $_ != 1;
            print(time(), "\n");
        }
    }
} else {
    $SIG{TTOU}='IGNORE';
    sleep 4;
    kill CONT => $pid
        or die $!;
    waitpid($pid, 0);
}