ipc.h

, ipc

- XSI interprocess communication access structure

Synopsis

#include <sys/ipc.h> 

Description

The <sys/ipc.h> header is used by three mechanisms for interprocess communication (IPC): messages, semaphores, and shared memory. All use a common structure type, ipc_perm, to pass information used in determining permission to perform an IPC operation.

The ipc_perm structure contains the following members:

uid_t  uid     /* owner's user ID */
gid_t  gid     /* owner's group ID */
uid_t  cuid    /* creator's user ID */
gid_t  cgid    /* creator's group ID */
mode_t mode    /* read/write permission

The uid_t, gid_t, mode_t, and key_t types are defined as described in <sys/types.h>. See types.h(3HEAD).

Definitions are provided for the constants listed below.

Mode bits:

IPC_CREAT

Create entry if key does not exist.

IPC_EXCL

Fail if key exists.

IPC_NOWAIT

Error if request must wait.

Keys:

IPC_PRIVATE

Private key.

Control commands:

IPC_RMID

Remove identifier.

IPC_SET

Set options.

IPC_STAT

Get options.

Attributes

See attributes(5) for descriptions of the following attributes:

See Also

ftok(3C), types.h(3HEAD), attributes(5), standards(5)