Cannot import some builtin modules from embedded boost python

Question

I am running python scripts from within my C++ application using boost::python . I get the error: ModuleNotFoundError: No module named 'math' . Some builtin modules work, but some don't. For example, import sys works.

I verified that I have a normal python installation and the modules are all imported correctly when I run python from command line.

I printed sys.path , sys.executable , sys.version , sys.builtin_module_names in both the embedded version and the command line version and there is only one difference - the builtin modules list is shorter when run from inside my C++ executable, with some modules are missing.

What am I missing?

Answer 1

FYI, I am running into the exact same problem.

I am running on RHEL 7 and am building a shared library that is part of a complex system. Of the following 4 calls, only calendar fails (returns null):

PyObject* t1 = PyImport_ImportModule("calendar");
PyObject* t2 = PyImport_ImportModule("itertools");
PyObject* t3 = PyImport_ImportModule("appdirs");
PyObject* t4 = PyImport_ImportModule("cython");

After trying a whole bunch of different modules/packages, it appears it works for built in packages like sys and itertools, AND it works for modules in site-packages (that is simple.py files in site-packages), but not when you have a full fledged package...a directory with an init .py file

If you put the call to PyImport_ImportModule in a try/catch block: