SYSIPC.H(7) Miscellaneous Information Manual SYSIPC.H(7)

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