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)

Reading the terminal size

In this recipe, we'll continue digging around our terminal. Here, we write a funny little program that reports the size of the terminal live. As you resize your terminal window (assuming you are using an X console application), you'll instantly see the new size being reported.

To make this work, we'll make use of both a special escape sequence and the ioctl() function.

Knowing how to use these two tools, escape sequences, and ioctl() will enable you to do some amusing things with the terminal.

Getting ready

To make the most of this recipe, it's best to use an X-Window console, such as xterm, rxvt, Konsole, Gnome Terminal, and so on.

You'll also need the GCC compiler, the Make tool, and the generic Makefile.

How to do it…

Here, we will write a program that first clears the screen using a special escape sequence, then fetches the terminal's size and prints to the screen:

  1. Write the following code...