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)

Using the dynamic library in a program

Now that we have created a dynamic library and installed it on our system, it's time to try it out in a program. We have actually been using dynamic libraries without even thinking about it since the very beginning of this book. Functions such as printf() and so on are all part of the standard library. In the The what and why of libraries recipe from earlier in this chapter, we used another dynamic library called cURL. In this recipe, we'll use our very own library that we installed in the previous recipe.

Knowing how to use custom libraries will enable you to use other developers' code, which will speed up the development process. There's often no need to reinvent the wheel.

Getting ready

For this recipe, we'll need the temperature.c code from the Using a static library recipe earlier in this chapter. That program will use the dynamic library. You'll also need to complete the previous recipe before attempting...