The basic structure of an extension module

An extension module written in C will have the following parts:

• A header segment, where you include all your external libraries and Python.h
• An initialization segment, where you define the module name and the functions in your C module
• A method structure array to define all the functions in your module
• An implementation segment, where you define all the functions that you would like to expose

The header segment

Header snippets are quite standard, just like a normal C module. We need to include the Python.h header file to give our C code access to the internals of the C-API. This file is present in <path_to_python>/include. We will be using an array object in our example code, hence we have included the numpy/arrayobject.h header file as well. We don't need to specify the full path of the header file here as the path resolution is taken care of in setup.py, which we will take a look at later:

/* 
Header Segment 
*/ 
 
#include...