NAME

sys/ipc.h - 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 structure ipc_perm 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>.

Definitions are given for the following 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 is declared as a function and may also be defined as a macro. Function prototypes must be provided for use with an ISO C compiler.

key_t  ftok(const char *, int);

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

ftok(), <sys/types.h>.