Inter-Process Communication

This chapter describes the GNU C Library inter-process communication primitives

Semaphores

The GNU C Library implements the semaphore APIs as defined in POSIX and System V. Semaphores can be used by multiple processes to coordinate shared resources. The following is a complete list of the semaphore functions provided by the GNU C Library.

System V Semaphores

int semctl(intsemid, intsemnum, intcmd);

Preliminary:|MT-Safe|AS-Safe|AC-Unsafe corrupt/linux|SeeSection 1.2.2.1 POSIX Safety Concepts, page 2.

int semget(keytkey, intnsems, intsemflg);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|SeeSection 1.2.2.1 POSIX Safety Concepts, page 2.

int semop(intsemid, struct sembuf *sops, sizetnsops);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|SeeSection 1.2.2.1 POSIX Safety Concepts, page 2.

int semtimedop(intsemid, struct sembuf *sops, sizetnsops, conststruct timespec *timeout);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|SeeSection 1.2.2.1 POSIX Safety Concepts, page 2.

POSIX Semaphores

int sem_init(semt *sem, intpshared, unsigned intvalue);

Preliminary:|MT-Safe|AS-Safe|AC-Unsafe corrupt|SeeSection 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_destroy(semt *sem);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

sem_t *sem_open(const char *name, intoflag, ...);

Preliminary:|MT-Safe|AS-Unsafe init|AC-Unsafe init|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_close(semt *sem);

Preliminary:|MT-Safe|AS-Unsafe lock|AC-Unsafe lock|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_unlink(const char *name);

Preliminary:|MT-Safe|AS-Unsafe init|AC-Unsafe corrupt|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_wait(semt *sem);

Preliminary:|MT-Safe|AS-Safe|AC-Unsafe corrupt|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_timedwait(semt *sem, const struct timespec *abstime);

Preliminary:|MT-Safe|AS-Safe|AC-Unsafe corrupt|See Section 1.2.2.1 POSIX Safety Concepts, page 2.

int sem_trywait(semt *sem);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|See Section 1.2.2.1 POSIX SafetyConcepts, page 2.

int sem_post(semt *sem);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|See Section 1.2.2.1 POSIX SafetyConcepts, page 2.

int sem_getvalue(semt *sem, int *sval);

Preliminary:|MT-Safe|AS-Safe|AC-Safe|See Section 1.2.2.1 POSIX SafetyConcepts, page 2.