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 a simple C program for Linux

In this recipe, we will be building a small C program that sums up the values that are passed to the program as arguments. The C program will contain some essential elements we need to know about when programming for Linux. These elements are return values, arguments, and help texts. As we progress through this book, these elements will show up, time and time again, along with some new ones that we'll learn about along the way.

Mastering these elements is the first step to writing great software for Linux.

Getting ready

The only thing you'll need for this recipe is the C source code, sum.c, and the GCC compiler. You can choose to type the code in yourself or download it from GitHub. Typing it in yourself gives you the benefit of learning how to write it.

How to do it…

Follow these steps to write your first program in Linux:

  1. Open a text editor and type in the following code, naming the file sum.c. The program...