Po_mutex * restrict mtx
Unlocks a Po_mutex the calling thread has a lock on.
mtx (in) should point to a Po_mutex object previously successfully locked (in the same thread) with Po_LockMutex(). Passing NULL is an error.
Doesn't return a value.
Unlocking a Po_mutex that the thread doesn't have a lock on is undefined (so don't do it).
Since locking a Po_mutex can be recursive, the number of calls to this function must match the number of calls to Po_LockMutex() and/or Po_TryLockMutex() before the lock is actually released.