Round Trip: C to Python to C Module

[Eric Frederich]

I have a proprietary software PropSoft that I need to extend.
They support extensions written in C that can link against PropLib to
interact with the system.

I have a Python C module that wraps a couple PropLib functions that I
call PyProp.
>From an interactive Python shell I can import PyProp and call a function.
None of these functions really do anything outside the context of
being logged into the PropSoft software; so all the functions fail
when running from Python alone.

To my amazement, I was able to run PyRun_SimpleString("import
PyProp\nPyProp.some_function()") without setting PYTHONPATH or
anything.  How this works, I don't know and I don't really care (at
the moment anyway).

The problem I'm having now is how do I return things from my Python
script back to C?
Ultimately I won't be hard coding python inside of PyRun_SimpleString
but loading the script from a file.
So, how do I return values back to C?  Python functions return values
but running a python script?... doesn't that just have an exit status?
Is there a mechanism for doing this?

Thanks in advance,
~Eric