This function calls the System V IPC system call
(2) to perform
semaphore operations such as signaling and waiting.
require "ipc.ph"; require "sem.ph";
The following code waits on semaphore
$semop = pack "s*", $semnum, -1, 0; die "Semaphore trouble: $!\n" unless semop $semid, $semop;
To signal the semaphore, simply replace
This function is available only on machines supporting System V IPC.