zeromq/pyzmq

import threading
from multiprocessing import Process
import zmq

def step1(context=None):
    """Step 1"""
    context = context or zmq.Context.instance()
    # Signal downstream to step 2
    sender = context.socket(zmq.PAIR)
    sender.connect("inproc://step2")

    sender.send(b"from step1")

def step2(context=None):
    """Step 2"""
    context = context or zmq.Context.instance()
    # Bind to inproc: endpoint, then start upstream thread
    receiver = context.socket(zmq.PAIR)
    receiver.bind("inproc://step2")

    #thread = threading.Thread(target=step1)
    thread = Process(target=step1, args=(context,))
    thread.start()

    # Wait for signal
    msg = receiver.recv()
    print("%s" % msg)

    # Signal downstream to step 3
    sender = context.socket(zmq.PAIR)
    sender.connect("inproc://step3")
    sender.send(b"from step2")

def main():
    """ server routine """
    # Prepare our context and sockets
    context = zmq.Context.instance()

    # Bind to inproc: endpoint, then start upstream thread
    receiver = context.socket(zmq.PAIR)
    receiver.bind("inproc://step3")

    #thread = threading.Thread(target=step2)
    thread = Process(target=step2, args=(context,))
    thread.start()

    # Wait for signal
    msg = receiver.recv()
    print("%s" % msg)

    print("Test successful!")

    receiver.close()
    context.term()

if __name__ == "__main__":
    main()

So far this example (changed with multiprocessing in mind) fails. I took, and changed it from here: https://github.com/companycy/cpp_by_example/blob/master/inproc_example.py

It gives this result:

Assertion failed: ok (src/mailbox.cpp:99)
Assertion failed: ok (src/mailbox.cpp:99)
[1]    3015255 abort (core dumped)  python test-pymq.py