How to add a directory to PYTHONPATH from CMake?

Question

I have a c++ library which has a python API library based on Boost.python included in the directory structure.

module
|_python_files
|_cpp_files

Is there a standard way to configure CMakelist so that it automatically adds the library containing the python files to PYTHONPATH?

Answer 1

In case you use FindPython you should be able to use

Python_add_library (my_module MODULE src1.cpp)

Or you could add the path to PYTHONPATH:

list(APPEND PYTHONPATH "${CMAKE_CURRENT_DIR}/module/python_files") 

Otherwise, you want to add python_files to your python definition path:

export PYTHONPATH="${PYTHONPATH}:../module/python_files"

Answer 2

based on documentation this should od the trick:

set(ENV{PYTHONPATH} "${CMAKE_CURRENT_SOURCE_DIR}/module/python_files")

I didn't test that.

Note that PYTHONPATH environment variable is read and used by python interpreter not by cmake. It is used when trying locating python libraries imported by python code.