C:\test>perl -le "for (1..100) {Win32::Spawn( $ENV{ComSpec},'/c echo>null', $pid );print qq[$_\tpid:$pid\t],$?==-1 ? $! : 'OK' };" 1 pid:5492 OK 2 pid:5256 OK 3 pid:1860 OK ... 93 pid:2236 OK 94 pid:2308 OK 95 pid:4012 OK 96 pid:4796 OK 97 pid:4636 OK 98 pid:4780 OK 99 pid:244 OK 100 pid:4800 OK