June 2002
Beginner
759 pages
80h 42m
English
shmctl
shmctl id, cmd, arg
Calls the System V IPC system call, shmctl(2), for performing operations on
shared memory segments. If cmd is
&IPC_STAT, then
arg must be a variable that will hold
the returned shmid_ds
structure. The function returns like ioctl: the undefined value for error,
"0 but true" for 0, or the actual return value otherwise.
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.