Reference: shmctl
Author: Ellen Siever, Stephen Spainhour & Nathan Patwardhan
Date: 1999-07-02T01:37:56Z

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| Chapter 5 Function Reference |

## 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 zero, 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.

Reference: shift |  | Reference: shmget