PyBox | PyBox provides you with a compilation of many such Python | Game Engine library

Apparently, [MS.Docs]: GetGUIThreadInfo function is not wrapped by PyWin32, so alternative ways must be used. One of them is calling it via [Python 3.Docs]: ctypes - A foreign function library for Python (involves writing a lot of extra code).

code00.py:

You need to return a Python int. In C/C++ source this is a PyLongObject (Which is a subtype of PyObject, so you can cast a PyLongObject* to a PyObject* and back). To convert a C++ int into a PyObject* Python int, use PyObject* PyLong_FromLong(long):

self->bx->number_bananas is not a PyObject* so can't be increfed or decrefed. Instead you want to be converting it to/from a PyObject*. In Python3 you do this with various PyLong_* functions.

Some untested code would be:

The basic issue is that bx is a pointer, so bx->id could literally anywhere in memory relative to PyBox. Therefore offsetof can never work and thus defining the members in PyMemberDef also can never work.

One solution would be to change the class definition so Box is part of the class (and so an offset is meaningful). This may or may not make sense depending on your C++ code: