sub subroutine {
    foreach (1..4) {
        my $pid= fork;
        die "Can't fork: $!\n"   unless  defined $pid;
        if(  ! $pid  ) {
            # do something here 
            exit(0);
        }
    }
    foreach (1..4) {
        wait();
        print "$_ child finished; status is: $?\n";
    }
}