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)

Changing C standards

In this recipe, we will be learning and exploring different C standards, what they are, why they matter, and how they affect our programs. We will also learn how to set the C standard at compile time.

The most commonly used C standards today are C89, C99, and C11 (C89 for 1989, C11 for 2011, and so on). Many compilers still default to using C89 because it's the most compatible, widespread, and complete implementation. However, C99 is a more flexible and modern implementation. Often, under newer versions of Linux, the default is C18, together with some POSIX standards.

We will write two programs and compile them with both C89 and C99, and see their differences.

Getting ready

All you need for this recipe is a Linux computer with GCC installed, preferably via the meta-package or package group described in Chapter 1, Getting the Necessary Tools and Writing our First Linux Programs.

How to do it…

Follow along to explore the differences...