Name
shmctl
Synopsis
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.
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