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)

Stepping inside a function with GDB

When we use the next command in a program with a function, it will simply execute the function and move on. However, there's another command called step that will enter the function, step through it, and then return to main() again. In this recipe, we'll examine the difference between next and step.

Knowing how to step into a function with GDB will help you debug an entire program, including its functions.

Getting ready

For this recipe, you'll need the GDB tool, the GCC compiler, the Makefile we wrote in the Starting GDB recipe in this chapter, and the Make tool.

How to do it…

In this recipe, we'll write a small program that has a function. Then, we'll step into that function with GDB, using the step command:

  1. Write the following code in a file and save it as area-of-circle.c. The program takes the radius of a circle as an argument and prints its area:
    #include <stdio.h>
    #include <stdlib...