Embedded Python and multiprocessing on Windows?

[Apple]

A quick update as I found a minor workaround, but I don't quite understand why it works this way or how I would fix it to work differently:

So my program runs one script file, and multiprocessing commands from that script file seem to fail to spawn new processes.

However, if that script file calls a function in a separate script file that it has imported, and that function calls multiprocessing functions, it all works exactly the way it should.

So now I think my question is why does it behave this way, and is there anything I can do to fix the behavior in the first script? It's not the end of the world to need 2 scripts, but it sure would be a lot cleaner with just one.

On Thursday, August 9, 2018 at 12:09:36 PM UTC-4, Apple wrote:
> I've been working on a project involving embedding Python into a Windows application. I've got all of that working fine on the C++ side, but the script side seems to be hitting a dead end with multiprocessing. When my script tries to run the same multiprocessing code that works in a non-embedded environment, the code doesn't appear to be executed at all.
> 
> A StackOverflow thread gave me a few ideas to try out, so I gave it a shot with these lines added:
> 
> sys.argv = ['C:\\path\\to\\script.py']
> mp.set_executable("C:\\Python37\\python.exe")
> p = mp.Process(target=somefunction)
> p.start()
> 
> Still no joy. However, a Python.exe window does pop up for a tenth of a second, so *something* is happening.
> 
> So does multiprocessing actually work in embedded Python, or am I at a dead end here? My guess is that it's probably linked to Windows not having fork, so the combination of being embedded and having to spawn is making things go goofy.