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(3) 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(3).
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 shall fail
if:
- [EINVAL]
- The sem argument is not a valid semaphore.
The sem_destroy () function may fail
if:
- [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(3) , semget(3) , semop(3) , sem_init(3) , sem_open(3) , the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <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.
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