Reference: shmget

shmget

shmget key, size, flags

Calls the System V IPC system call, shmget(2). The function returns the shared memory segment 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 "shm.ph";

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