VMS Help POSIX Threads, TIS routines, tis_unlock_global, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    This routine unlocks the global mutex. Because the global mutex
    is recursive, the unlock occurs when each call to tis_lock_
    global() has been matched by a call to this routine. For example,
    if your program called tis_lock_global() three times, tis_unlock_
    global() unlocks the global mutex when you call it the third
    time.

    For more information about actions taken when threads are
    present, refer to the pthread_unlock_global_np() description.