Description

   The sem_unlink function removes a semaphore named by the name
   string. If the semaphore is referenced by other processes, sem_
   unlink does not change the state of the semaphore.

   If other processes have the semaphore open when sem_unlink is
   called, the semaphore is not destroyed until all references to
   the semaphore have been destroyed by calls to sem_close. The sem_
   unlink function returns immediately; it does not wait until all
   references have been destroyed.

   Calls to sem_open to recreate or reconnect to the semaphore refer
   to a new semaphore after sem_unlink is called.