ipc(3head) [freebsd man page]
ipc.h(3HEAD) Headers ipc.h(3HEAD) NAME
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: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
ftok(3C), types.h(3HEAD), attributes(5), standards(5) SunOS 5.10 10 Sep 2004 ipc.h(3HEAD)
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sem.h(3HEAD) Headers sem.h(3HEAD) NAME
sem.h, sem - semaphore facility SYNOPSIS
#include <sys/sem.h> DESCRIPTION
The <sys/sem.h> header defines the following constants and structures. Semaphore operation flags: SEM_UNDO Set up adjust on exit entry. Command definitions for the semctl() function are provided as listed below. See semctl(2). GETNCNT Get semncnt. GETPID Get sempid. GETVAL Get semval. GETALL Get all cases of semval. GETZCNT Get semzcnt. SETVAL Set semval. SETALL Set all cases of semval. The semid_ds structure contains the following members: struct ipc_perm sem_perm /* operation permission structure */ unsigned short sem_nsems /* number of semaphores in set */ time_t sem_otime /* last semop() time */ time_t sem_ctime /* last time changed by semctl() */ The pid_t, time_t, key_t, and size_t types are defined as described in <sys/types.h>. See types.h(3HEAD). A semaphore is represented by an anonymous structure containing the following members: unsigned short semval /* semaphore value */ pid_t sempid /* process ID of last operation */ unsigned short semncnt /* number of processes waiting for semval to become greater than current value */ unsigned short semzcnt /* number of processes waiting for semval to become 0 */ The sembuf structure contains the following members: unsigned short sem_num /* semaphore number */ short sem_op /* semaphore operation */ short sem_flg /* operation flags */ All of the symbols from <sys/ipc.h> are defined when this header is included. See ipc.h(3HEAD). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
semctl(2), semget(2), semop(2), ipc.h(3HEAD), types.h(3HEAD), attributes(5), standards(5) SunOS 5.11 10 Sep 2004 sem.h(3HEAD)