I’m trying to include C++ header and source files in my Python package because I use them in the Python files of my package (via cppyy). It works fine on my local PC, but when I build the package for PyPI, install and import it, I get an error that the headers/C++ files don’t exist:

import eefpy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/root/tests/venv/lib/python3.10/site-packages/eefpy/__init__.py", line 2, in <module>
    cppyy.include('solver/eef.h')
  File "/root/tests/venv/lib/python3.10/site-packages/cppyy/__init__.py", line 267, in include
    raise ImportError('Failed to load header file "%s"%s' % (header, err.err))
ImportError: Failed to load header file "solver/eef.h"
input_line_18:1:10: fatal error: 'solver/eef.h' file not found
#include "solver/eef.h"
         ^~~~~~~~~~~~~~

I tried to add the folder that includes the C++ files in the setup.py file as follows:

...
include_package_data=True,
package_data={
    'eefpy': ['../solver/*'],
},
...

I also tried adding the folder/files to MANIFEST.in:

recursive-include solver *

This builds the package and includes the solver folder, but it saves it outside the main package directory in the installed package, so when I install it in my virtual environment, I see it under site-packages as a separate directory, not within the package.

I expected the C++ files to be included within the package directory (e.g., eefpy/solver/) so that they are accessible when the package is installed and imported.