I am currently embedding Python3 into my C++ application.
We also ships a defined version of Python3. Currently Py_Initialize finds the system python in /usr/lib/python3.5 (which we do not want). I could not yet figure out how I can strip the search path before calling Py_Initialize and force it to search in my custom path.
It can be done with Py_SetPythonHome.
Embedding specific Python