Basic C++ Python Extension

hellomodule.cpp

/*
This file will create a python module named `hello` (l. 42)
It's important that the project is set to output a file named
`hello.pyd` which must be identical to the module name.

Python will then search for the method `PyInit_hello(void)`
and call it. There, `PyModule_Create` must be called with
a `struct PyModuleDef` as argument.

Within there, the module's methods are defined. This is done
via a `PyMethodDef` mapping Python methods to the according
C++ methods.

Lastly, methods can be defined, returning and taking `PyObject*`s.
If nothing is returned, `Py_RETURN_NONE` must be called.
*/


#include <Python.h>

static PyObject*
say_hello(PyObject* self, PyObject* args)
{
    const char* name;

    if (!PyArg_ParseTuple(args, "s", &name))
        return NULL;

    printf("Hello %s!\n", name);
    
    Py_RETURN_NONE;
}

static PyMethodDef HelloMethods[] = {
    {"hello",  say_hello, METH_VARARGS, "Say Hello."},
    {NULL, NULL, 0, NULL}        /* Sentinel */
};

static struct PyModuleDef HelloModule =
{
	PyModuleDef_HEAD_INIT,
   "hello",   /* name of module */
   NULL, /* module documentation, may be NULL */
   -1,       /* size of per-interpreter state of the module,
                or -1 if the module keeps state in global variables. */
   HelloMethods
};

PyMODINIT_FUNC
PyInit_hello(void)
{
     return PyModule_Create(&HelloModule);
}