C++ Python append to inittab from pyd file

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C++

Python

Boost

I am trying to expose a c++ class to python using boost, and extract a object defined in python in c++ side.

What I have tried:

I defined my c++ class in the file MyInt.h:
<pre>
    struct MyInt
    {
	   int i_;
    };

If I define the BOOST_PYTHON_MODULE in the project everything works fine. For example this code works well:

#include "MyInt.h"

BOOST_PYTHON_MODULE(Example)
{
    bpy::class_<MyInt>("MyInt")
    .def_readwrite("i_", &MyInt::i_);
}

int main()
{

    PyImport_AppendInittab("Example", &PyInit_Example);
    Py_Initialize();
    try
    {

        bpy::object main_module = bpy::import("__main__");
        bpy::object main_namespace = main_module.attr("__dict__");
        main_namespace["ex"] = bpy::import("Example");
        bpy::exec("i = ex.MyInt()", main_namespace, main_namespace);
        bpy::exec("i.i_ = 5", main_namespace, main_namespace);

        MyInt& myI = bpy::extract<MyInt&>(main_namespace["i"]);
        std::cout << "MyI.i_ : " << myI.i_ << std::endl;
    }
    catch (bpy::error_already_set& pye)
    {
        PyErr_Print();
    }

    Py_Finalize();
    system("Pause");

}

Now, if I build the Example.pyd file using the same BOOST_PYTHON_MODULE, i can import it in python but the following code in c++ doesn't work:

#include "MyInt.h"

int main()
{
    HMODULE hLib = LoadLibrary("Example.pyd");
    if (hLib)
    {
        typedef PyObject* (*PFN) ( void);
        PFN init_func = (PFN)GetProcAddress(hLib,"PyInit_Example");
        if (init_func != 0)
        {
            int y = 0;
            if ((y = PyImport_AppendInittab("Example", init_func)) == -1)
            {
                std::cout << "PyImport failed" << std::endl;
            }
        }
    }

    Py_Initialize();

    try
    {

        bpy::object main_module = bpy::import("__main__");
        bpy::object main_namespace = main_module.attr("__dict__");
        main_namespace["ex"] = bpy::import("Example");
        bpy::exec("i = ex.MyInt()", main_namespace, main_namespace);
        bpy::exec("i.i_ = 5", main_namespace, main_namespace);
        MyInt& myI = bpy::extract<MyInt&>(main_namespace["i"]);
        std::cout << "MyI.i_ : " << myI.i_ << std::endl;
    }
    catch (bpy::error_already_set& pye)
    {
        PyErr_Print();
    }

    Py_Finalize();
    system("Pause");
    if (hLib) FreeLibrary(hLib);

}

it seems that the load of library and the PyImport_AppendInitTab call is ok, but the following error is thrown:

TypeError: No registered converter was able to extract a C++ reference to type struct MyInt from this Python object of type MyInt


How can i fix this error?
Is it possible to register a converter from pyd file?

thanks