Create a Python3 module at runtime while initialize an embedded Python - c++

Question

We have a DLL that implements a custom programming language. What I want to do is adding support for the python language keeping the same code for "API function".
I have succefully embedded python in this DLL, now I'm approaching the problem to expose all the old function as a python module.
Now this DLL doesn't expose the API function as interface function but it's installed (as function pointer) to the language engine. In this way it's impossible to create a new python module (a new DLL). But I need to keep the compatibility with the old method...
It's possible to create (and install) at runtime a module defined in the same DLL where the Python is located?
I think something like calling the PyInit_xxxx method after PyInitialize();

Answer 1

This has gotten substantially more complicated in Python 3 (vs. how it was in Python 2), but I've gotten it working for my code, so I hope this works for you as well.
// Python 3's init function must return the module's PyObject* made
// with PyModule_Create()
PyObject* initspam();
const char* spam_module_name;
int main(int argc, char **argv)
{
Py_Initialize();
PyImport_AddModule(spam_module_name);
PyObject* module = initspam();
PyObject* sys_modules = PyImport_GetModuleDict();
PyDict_SetItemString(sys_modules, spam_module_name, module);
Py_DECREF(module)
...
}
I found an example of this in the python 3 source code:
Python-3.4.2\Python\pythonrun.c : import_init()
That has much better error checking and such than my example above.

Answer 2

I've solved using a code like this before Py_Initialize();
/* Add a built-in module, before Py_Initialize */
PyImport_AppendInittab("xxx", PyInit_xxx);

Answer 3

The easiest way to handle this is to statically initialize your statically-linked modules by directly calling initspam() after the call to Py_Initialize() or PyMac_Initialize():
int main(int argc, char **argv)
{
/* Pass argv[0] to the Python interpreter */
Py_SetProgramName(argv[0]);
/* Initialize the Python interpreter. Required. */
Py_Initialize();
/* Add a static module */
initspam();
An example may be found in the file Demo/embed/demo.c in the Python source distribution.