Does Pybind11 have problems with name mangling?

Question

I am trying to read a C++ code (long and nested) in Python. My C++ files are:

• celinoid_propagator.cpp --> contains the "main" function.
• celinoid_propagator_lib.cpp --> contains the methods of each of the functions. The only function I want to use is here.
• celinoid_propagator_lib.h --> contains the declarations of variables, structures, functions, etc, all inside a class named "MODEL_GAUSS".

I have tried with ctypes but no luck. After some research (and because of a suggestion in my last question), I have decided to try Pybind11.

In principle, it seems more straightforward to use. I am building the project with Cmake. Both the cmake command and the make command work fine.

However, when I try to run my .py program I get the following error:

Traceback (most recent call last): File "/home/milagros/Desktop/OPUS/C-Python/C-Python/pybind11/program.py", line 3, in . from celinoid import MODEL_GAUSS ImportError: /home/milagros/Desktop/OPUS/C-Python/pybind11/build/celinoid.cpython-311-x86_64-linux-gnu.so: undefined symbol: _ZN11MODEL_GAUSS27generate_syntetic_magnitudoEPddi

This looks like there is a problem with the mangled names.

This is my .cpp wrapper:

// model_gauss-wrapper.cpp

  #include <pybind11/pybind11.h>
  #include "celinoid_propagator_lib.h"

  namespace py = pybind11;
  constexpr auto byref = py::return_value_policy::reference_internal;

  PYBIND11_MODULE(celinoid, m) {
      m.doc() = "Model Gauss for celinoid propagator";

      py::class_<MODEL_GAUSS>(m, "Model_Gauss")
      .def(py::init<>())  
      .def("generate_syntetic_magnitudo", &MODEL_GAUSS::generate_syntetic_magnitudo, py::call_guard<py::gil_scoped_release>());
    }

Somewhere I read that I should put "extern "C" {#include "celinoid_propagator_lib.h"}" but it really doesn't change anything.

And here is my CMake file:

cmake_minimum_required(VERSION 3.15)
project(celinoid)

link_directories(${PROJECT_SOURCE_DIR})

find_package(pybind11 REQUIRED)

pybind11_add_module(celinoid model_gauss-wrapper.cpp)