Destroys an unnamed semaphore.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <semaphore.h>

      int sem_destroy  (sem_t *sem);

1 - Argument

 sem

    The unnamed semaphore to be destroyed. Use the sem argument that
    was supplied to, and filled in by, the previous call to sem_init.

2 - Description

    The sem_destroy function destroys an unnamed semaphore indicated
    by sem. Only a semaphore created using sem_init may be destroyed
    using sem_destroy.

    The potential for deadlock exists if a process calls sem_destroy
    for a semaphore while there is a pending sem_wait, because a
    process may be waiting for a poster that has not yet opened the
    semaphore.

3 - Return Values

    0                  Successful completion.
    -1                 Indicates an error. The function sets errno
                       to one of the following values, without
                       destroying the semaphore indicated by the
                       sem argument:

                       o  EINVAL - The sem argument is not a valid
                          semaphore.

                       o  ENOSYS - The function is not implemented.

                       o  EVMSERR - OpenVMS specific nontranslatable
                          error code.

                       o  EBUSY - The processes are blocked on the
                          semaphore.