27.1 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.

27.1.1 System V Semaphores

Function: int semctl (int semid, int semnum, int cmd);

Preliminary: | MT-Safe | AS-Safe | AC-Unsafe corrupt/linux | See POSIX Safety Concepts.

Function: int semget (key_t key, int nsems, int semflg);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Function: int semop (int semid, struct sembuf *sops, size_t nsops);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Function: int semtimedop (int semid, struct sembuf *sops, size_t nsops, const struct timespec *timeout);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

27.1.2 POSIX Semaphores

Function: int sem_init (sem_t *sem, int pshared, unsigned int value);

Preliminary: | MT-Safe | AS-Safe | AC-Unsafe corrupt | See POSIX Safety Concepts.

Function: int sem_destroy (sem_t *sem);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Function: sem_t *sem_open (const char *name, int oflag, ...);

Preliminary: | MT-Safe | AS-Unsafe init | AC-Unsafe init | See POSIX Safety Concepts.

Function: int sem_close (sem_t *sem);

Preliminary: | MT-Safe | AS-Unsafe lock | AC-Unsafe lock | See POSIX Safety Concepts.

Function: int sem_unlink (const char *name);

Preliminary: | MT-Safe | AS-Unsafe init | AC-Unsafe corrupt | See POSIX Safety Concepts.

Function: int sem_wait (sem_t *sem);

Preliminary: | MT-Safe | AS-Safe | AC-Unsafe corrupt | See POSIX Safety Concepts.

Function: int sem_timedwait (sem_t *sem, const struct timespec *abstime);

Preliminary: | MT-Safe | AS-Safe | AC-Unsafe corrupt | See POSIX Safety Concepts.

Function: int sem_trywait (sem_t *sem);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Function: int sem_post (sem_t *sem);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.

Function: int sem_getvalue (sem_t *sem, int *sval);

Preliminary: | MT-Safe | AS-Safe | AC-Safe | See POSIX Safety Concepts.