SEM_DESTROY(3P)

NAME
sem_destroy - destroy an unnamed semaphore (REALTIME)

SYNOPSIS

#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 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.

The following sections are informative.

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>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .