this stuff always seemed a mess. in practice i've always just used async io (non-blocking) and condition variables with shutdown flags. trying to preemptively

this stuff always seemed a mess. in practice i've always just used async io (non-blocking) and condition variables with shutdown flags. trying to preemptively terminate a thread in a reliable fashion under linux always seemed like a fool's errand. fwiw. it's not all that important, they get cleaned up at exit anyway. (and one should not be relying on operating system thread termination facilities for this sort of thing.)