The `multiprocessing.Pool` uses a `multiprocessing.Queue` in the background to retrieve the results after completion.

The `multiprocessing.Queue` in turn uses `multiprocessing.connection.Pipe` and sends the pickled objects over to the wire.

So I don't see how this is any better than ZMQ.

Just because stuff has an API that doesn't look like message passing doesn't mean it can't be doing that in the background. Which is funny, because that's the whole point of ZProc.

I realize the subtle difference that Cpython uses pipes, not sockets, unlike ZMQ. But that doesn't really make a difference now, does it?

Proof:

Process Pool worker, returning the result by using `outqueue.put()`

https://github.com/python/cpython/blob/86b89916d1b0a26c1e77f...

multiprocessing Queue, initializing a Pipe

https://github.com/python/cpython/blob/86b89916d1b0a26c1e77f...

multiprocessing Queue serializing data to send it using that Pipe

https://github.com/python/cpython/blob/86b89916d1b0a26c1e77f...