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.