Python C api iterate through classes in module

Question

In this case, the module is a python script loaded from a file. I can't find anything on the Internet about this.

If I could loop through all objects in the module, I can filter for classes using PyClass_Check. But I don't know how to do this either.

// Load
Py_SetProgramName(argv[0]);
Py_Initialize();
PySys_SetArgv(argc, argv);

inithello();

PyObject *pModule = PyImport_ImportModule("test123");

if (pModule != NULL) {      
    // iterate through classes.
    Py_DECREF(pModule);
} else {
    PyErr_Print();
    std::cerr << "Failed to load module" << std::endl;
    return 1;
}
Py_Finalize();

The reason for this is that the user will be defining game content using classes derived from base classes.

class grass_tile(game.Tile):
    def __init__(x, y):
        // initialise

I have tried using PyObject_GetIter() on the module, but it returns NULL (obviously not iterate-able that way.)

Answer 1

Worked it out. Hope this helps someone else.

PyObject *dict = PyModule_GetDict(pModule);
PyObject *key, *value = NULL;
Py_ssize_t pos = 0;

while (PyDict_Next(dict, &pos, &key, &value)) {
    if (PyClass_Check(value)) {
        std::cerr << "IsClass" << std::endl;
    } else {
        std::cerr << "NotClass" << std::endl;
    }
}