My apparent memory leak from the other day did in fact turn out to be leaking thread resources.

The key: Don’t Join on Yourself! If a thread attempts to call pthread_join on itself it is likely to cause a deadlock in that thread that you may never know about. Particularly if you are using some sort of worker-thread model that creates and destroys threads often. A simple way to catch this problem would be to add an assertion in your destructor.

class threaded_class
        // if somehow this thread tries to join on itself, perhaps by causing this
        // instance of threaded_class to get destroyed, cause an assertion failure
        // so we can investigate it
        assert(!pthread_equal(m_worker_thread, pthread_self()));

    pthread_t m_worker_thread;