ipc.h, ipc - XSI interprocess communication access structure
#include <sys/ipc.h>
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:
Create entry if key does not exist.
Fail if key exists.
Error if request must wait.
Keys:
Private key.
Control commands:
Remove identifier.
Set options.
Get options.
See attributes(7) for descriptions of the following attributes:
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