This chapter explained one of the most advanced topics in the book. We discussed the reasons and tools for building Python extensions. We started from writing pure C extensions that depend only on Python/C API and then re-implemented them with Cython to show how easy it can be if you only choose the proper tool.

There are still some reasons for doing things the hard way and using nothing more than the pure C compiler and the Python.h headers. Anyway, the best recommendation is to use tools such as Cython or Pyrex (not featured here) because it will make your codebase more readable and maintainable. It will also save you from most of the issues caused by incautious reference counting and memory management.

Our discussion of extensions ended with the presentation of ctypes and CFFI as an alternative way to solve the problems of integrating shared libraries. Because they do not require writing custom extensions to call functions from compiled binaries, they should be your tools of choice for doing that—especially if you don't need to use custom C code.

In next chapter, we will take a short rest from low-level programming techniques and delve into topics that are no less important—code management and version control systems.