How to find minimum versions of python interpreter and libs using CMake

Question

I am building a C extension using pybind11 with CMake. I used to do this with:

find_package(Python3 3.7 REQUIRED)
find_package(PythonLibs 3.7 REQUIRED)

without any issues. Now I need python 3.8 and changed it to:

find_package(PythonInterp 3.8 REQUIRED)
find_package(PythonLibs 3.8 REQUIRED)

However, despite libpython3.8.so being in the same folder as libpython3.7m.so CMake does not find it. It returns:

Could NOT find PythonLibs: Found unsuitable version "3.7.5", but required
is at least "3.8" (found /usr/lib/x86_64-linux-gnu/libpython3.7m.so)

When researching this I noticed that PytonInterp and PythonLibs are deprecated since CMake 3.12 and FindPython is preferred. So I tried:

find_package(Python3)

This finds my python 3.8 interpreter, but not my python 3.8 libraries. Hence, I still cannot use the package, as

mypy.cpython-37m-x86_64-linux-gnu.so

is based on python 3.7 libraries. How can I ensure it also finds my 3.8 libraries? As said, they are in the same folder.

Answer 1

The documentation for the FindPython module states:

If no COMPONENTS are specified, Interpreter is assumed.

So, yes, since you haven't specified any COMPONENTS , only the interpreter is found.

If you want CMake to find the Python include directories and libraries , you should specify Development :

find_package(Python3 COMPONENTS Interpreter Development)