pthread_unlock_global_np - Unlocks the DECthreads global mutex.
DECthreads POSIX 1003.1c Library (libpthread.so)
This routine unlocks the DECthreads global mutex. Because the global mutex is recursive, the unlock occurs when each call to pthread_lock_global_np(3) has been matched by a call to this routine. For example, if you called pthread_lock_global_np(3) three times, pthread_unlock_global_np(3) unlocks the global mutex when you call it the third time.
If no threads are waiting for the DECthreads global mutex, it becomes unlocked with no current owner. If one or more threads are waiting to lock the global mutex, this routine causes one thread to unblock and try to acquire the global mutex. The scheduling policy is used to determine which thread is awakened. For the policies SCHED_FIFO and SCHED_RR, a blocked thread is chosen in priority order, using first-in/first-out (FIFO) within priorities.
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows: Successful completion. The mutex is unlocked or owned by another thread.
Manuals: Guide to DECthreads and Programmer's Guide