What is the correct way to determine the number of running/busy threads (thread_count)? I think you need to go buy a basic book on threaded programming. This list is not that book. ---- Not sure the reason for that comment. Mine seems a logical approach and is almost working. My only other experience with threading was with Python and it had a similar method called threading.active_count() So my logic (while maybe wrong) is to: 1. Get the number of cores using boost::thread::hardware_concurrency() 2. Fill a std::queue container with jobs for the threads. 3. While the container is not empty and there are less active threads than boost::thread::hardware_concurrency(), then start a new thread. Again, not sure why that would be deserving of a condescending response, it seems logical. _________________________________________________________________ Hotmail: Trusted email with Microsoft’s powerful SPAM protection. https://signup.live.com/signup.aspx?id=60969