Book Image

Secret Recipes of the Python Ninja

Book Image

Secret Recipes of the Python Ninja

Overview of this book

This book covers the unexplored secrets of Python, delve into its depths, and uncover its mysteries. You’ll unearth secrets related to the implementation of the standard library, by looking at how modules actually work. You’ll understand the implementation of collections, decimals, and fraction modules. If you haven’t used decorators, coroutines, and generator functions much before, as you make your way through the recipes, you’ll learn what you’ve been missing out on. We’ll cover internal special methods in detail, so you understand what they are and how they can be used to improve the engineering decisions you make. Next, you’ll explore the CPython interpreter, which is a treasure trove of secret hacks that not many programmers are aware of. We’ll take you through the depths of the PyPy project, where you’ll come across several exciting ways that you can improve speed and concurrency. Finally, we’ll take time to explore the PEPs of the latest versions to discover some interesting hacks.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Foreword
Contributors
Preface
Index

Forking processes


Process forking is the traditional method of parallelizing work, especially in *nix operating systems. When a program is forked, the OS simply makes a new copy of the original program, including its memory state, and proceeds to run the two versions of the program simultaneously. Naturally, the copied program can have its own forks, creating a hierarchy of the original, parent process, with numerous children and grandchildren copies. If the parent program is killed, the child processes can still operate normally.

How to do it...

In Python, to fork a process, all you have to do is import the os module and invoke the fork() function. The following example creates a simple parent/child process forking program:

  1. Import the os module, necessary to access fork():
        import os
  1. Define the child process:
        def child():
            print("Child {} calling".format(os.getpid()))
            os._exit(0)
  1. Create the parent process:
        def parent():
            for i in range(10...