NAME

sem_destroy - destroy an unnamed semaphore (REALTIME)

SYNOPSIS

[SEM] #include <semaphore.h>

int sem_destroy(sem_t *sem);

DESCRIPTION

The sem_destroy() function shall destroy the unnamed semaphore indicated by sem. Only a semaphore that was created using sem_init() may be destroyed using sem_destroy(); the effect of calling sem_destroy() with a named semaphore is undefined. The effect of subsequent use of the semaphore sem is undefined until sem is reinitialized by another call to sem_init().

It is safe to destroy an initialized semaphore upon which no threads are currently blocked. The effect of destroying a semaphore upon which other threads are currently blocked is undefined.

RETURN VALUE

Upon successful completion, a value of zero shall be returned. Otherwise, a value of -1 shall be returned and errno set to indicate the error.

ERRORS

The sem_destroy() function may fail if:

[EINVAL]

The sem argument is not a valid semaphore.

[EBUSY]

There are currently processes blocked on the semaphore.

EXAMPLES

None.

APPLICATION USAGE

The sem_destroy() function is part of the Semaphores option and need not be available on all implementations.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

semctl(), semget(), semop() , sem_init(), sem_open(), the Base Definitions volume of IEEE Std 1003.1-2001, <semaphore.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Realtime Extension.

Issue 6

The sem_destroy() function is marked as part of the Semaphores option.

The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support the Semaphores option.

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/114 is applied, updating the ERRORS section so that the [EINVAL] error becomes optional.