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)

The what and why of libraries

Before we go into the details of libraries, it's essential to understand what they are and why they matter to us. It's also important to understand the difference between static and dynamic libraries:

This knowledge will enable you to make smarter choices when making your own libraries.

A dynamic library is dynamically linked to the binary that uses it. What this means is that the library code isn't included in the binary. The library resides outside of the binary. This has several advantages. First, the resulting binary will be smaller in size since the library code isn't included. Second, the library can be updated without needing to recompile the binary. The disadvantage is that we can't move or delete the dynamic library from the system. If we do, the binary won't work anymore.

A static library, on the other hand, is included inside the binary file. The advantage of this is that the binary will be completely independent...