How can I recover the return value of a function passed to multiprocessing.Process?

Michael Zippo

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In the example code below, I"d like to recover the return value of the function worker. How can I go about doing this? Where is this value stored?

Example Code:

import multiprocessing

def worker(procnum):
    """worker function"""
    print str(procnum) + " represent!"
    return procnum


if __name__ == "__main__":
    jobs = []
    for i in range(5):
        p = multiprocessing.Process(target=worker, args=(i,))
        jobs.append(p)
        p.start()

    for proc in jobs:
        proc.join()
    print jobs

Output:

0 represent!
1 represent!
2 represent!
3 represent!
4 represent!
[<Process(Process-1, stopped)>, <Process(Process-2, stopped)>, <Process(Process-3, stopped)>, <Process(Process-4, stopped)>, <Process(Process-5, stopped)>]

I can"t seem to find the relevant attribute in the objects stored in jobs.

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We hope this article has helped you to resolve the problem. Apart from How can I recover the return value of a function passed to multiprocessing.Process?, check other __main__ Python module-related topics.

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Angelo Richtgofen

Prague | 2023-03-26

I was preparing for my coding interview, thanks for clarifying this - How can I recover the return value of a function passed to multiprocessing.Process? in Python is not the simplest one. Will use it in my bachelor thesis

Oliver Innsbruck

New York | 2023-03-26

Simply put and clear. Thank you for sharing. How can I recover the return value of a function passed to multiprocessing.Process? and other issues with __main__ Python module was always my weak point 😁. Will use it in my bachelor thesis

Olivia Innsbruck

Milan | 2023-03-26