Bryan, You'll get the same result without the lock. I'm not sure what this indicates. It may show that the contention on the lock and the race condition on i aren't always problems. It may show that generators, at least in CPython 2.4, provide thread safety for free. It does seem to disprove my statement that, "the yield leaves the lock locked".
More than that, I don't know. When threading is involved, different runs of the same code can yield different results. Can we be sure that each thread starts where the last one left off? Why wouldn't a thread just start where it had left off before? Of course, this case would have the potential for problems that Alex talked about earlier. Why would a generator object be any more reentrant than a function object? Because it has a gi_frame attribute? Would generators be thread-safe only in CPython? I started the discussion with simpler versions of these same questions. I'm convinced that using Queue is safe, but now I'm not convinced that just using a generator is not safe. cheers, Jess -- http://mail.python.org/mailman/listinfo/python-list
