[Chapter 3] 3.2.144 shmctl
Author: Larry Wall, Tom Christiansen & Randal L. Schwartz
Date: 1999-07-02T01:54:02Z

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| Chapter 3 Functions |

### 3.2.144 shmctl

    shmctl ID, CMD, ARG

This function calls the System V IPC system call, shmctl(2). If `CMD` is `&IPC_STAT`, then `ARG` must be a variable which 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.

3.2.143 shift |  | 3.2.145 shmget