sys_ipc.h(0p)

Usage

#include <sys/ipc.h>

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

Overview

The <sys/ipc.h> header is used by three mechanisms for XSI 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 <sys/ipc.h> header shall define the ipc_perm structure, which shall include 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 <sys/ipc.h> header shall define the uid_t, gid_t, mode_t, and key_t types as described in <sys/types.h>.

The <sys/ipc.h> header shall define the following symbolic constants.

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.

The following shall be declared as a function and may also be defined as a macro. A function prototype shall be provided.

key_t  ftok(const char *, int);

The following sections are informative.

Application usage

None.

Rationale

None.

Future directions

None.