/sys$common/syshlp/helplib.hlb POSIX Threads, TIS routines, tis_write_unlock, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    This routine unlocks a read-write lock that was acquired for
    write access.

    Upon completion of this routine, any thread waiting to acquire
    the lock for read access will have those acquisitions granted. If
    no threads are waiting to acquire the lock for read access, then
    a thread waiting to acquire it for write access will have that
    acquisition granted.