semget

semget 
key
, 
nsems
, 
size
, 
flags

Calls the System V IPC system call semget(2) . The function returns the semaphore ID, or the undefined value if there is an error. On error, it puts the error code into $! . Before calling, you should say:

require "ipc.ph";
require "sem.ph";

This function is available only on machines supporting System V IPC.