Python C Extension Hello World

build.sh

gcc -fpic --shared $(python-config --includes) greetmodule.c -o greetmodule.so

greetmodule.c

#include <Python.h>

static PyObject *
greet_name(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 GreetMethods[] = {
    {"greet", greet_name, METH_VARARGS, "Greet an entity."},
    {NULL, NULL, 0, NULL}
};

PyMODINIT_FUNC
initgreet(void)
{
    (void) Py_InitModule("greet", GreetMethods);
}

helloworld_in_c.py

import greet

def main():
    greet.greet('World')

if __name__ == "__main__":
    main()

Perfect! Just be sure to update the python-config --includes part of the gcc call to fit your python version, so for instance for python 3.8 I used python3.8-config --includes.