> I was thinking about a run time warning that is emitted if you call > os.fork() while multiple threads are active. It is ugly, but at least > it tells you you are doing something that will in most cases not work > correctly. The problem is that multiprocessing itself, by construction, uses fork() with multiple threads. Perhaps there's a way to use only non-blocking communication instead (rendering the helper threads useless), but that's not a trivial change.