Hello, I would like to use a counting semaphore - and to make sure that the threads will enter the semaphore by their arrival order. Is there a build-in counting semaphore with some kind of priority queue? if not, do boost threads have some kind of priority? I've noticed that some people implemented counting semaphore with condition variable, using wait and notify, but that doesn't keep the order. Is there another way to do it without actually implement my own priority queue? Thanks in advance, Gali