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 a static library

In this recipe, we'll use the static library created in the previous recipe in a program. Using a static library is a bit easier than using a dynamic library. We just add the static library (the archive file) to the list of files that will be compiled to a final binary.

Knowing how to use a static library will enable you to use other people's libraries and reuse your own code as static libraries.

Getting ready

For this recipe, you'll need both the convert.h file and the static library file, libconvert.a. You'll also need the GCC compiler.

How to do it…

Here, we will write a small program that uses our functions from the library we created in the previous recipe:

  1. Write the following code in a file and save it as temperature.c. Notice the syntax for including header files from the current directory.

The program takes two arguments: an option (either -f or -k for Fahrenheit or Kelvin) and a Celsius degree...