Book Image

Linux System Programming Techniques

By : Jack-Benny Persson
Book Image

Linux System Programming Techniques

By: Jack-Benny Persson

Overview of this book

Linux is the world's most popular open source operating system (OS). Linux System Programming Techniques will enable you to extend the Linux OS with your own system programs and communicate with other programs on the system. The book begins by exploring the Linux filesystem, its basic commands, built-in manual pages, the GNU compiler collection (GCC), and Linux system calls. You'll then discover how to handle errors in your programs and will learn to catch errors and print relevant information about them. The book takes you through multiple recipes on how to read and write files on the system, using both streams and file descriptors. As you advance, you'll delve into forking, creating zombie processes, and daemons, along with recipes on how to handle daemons using systemd. After this, you'll find out how to create shared libraries and start exploring different types of interprocess communication (IPC). In the later chapters, recipes on how to write programs using POSIX threads and how to debug your programs using the GNU debugger (GDB) and Valgrind will also be covered. By the end of this Linux book, you will be able to develop your own system programs for Linux, including daemons, tools, clients, and filters.
Table of Contents (14 chapters)

Writing your first threaded program

In this first recipe, we'll write a small program that checks whether two numbers are prime numbers—in parallel. While those two numbers are checked, each in their own thread, another thread will write dots in the terminal to indicate that the program is still running. A total of three threads will run in this program. Each thread will print its own result, so there's no need to save and return the values in this program.

Knowing the basics of threading will give the foundation to move along to more advanced programs.

Getting ready

For this recipe, you'll need the htop program so you can see the CPU load go up for two CPU cores. Of course, other similar programs work as well, such as KSysGuard for K Desktop Environment (KDE). It's also best if your computer has more than one CPU core. Most computers today have more than one core, even Raspberry Pis and similar small computers, so this shouldn't be a problem...