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)

Creating a dynamic library

While static libraries are convenient and easy to both create and use, dynamic libraries are more common. Just as we saw at the beginning of this chapter, many developers choose to provide a library and not only a program—for example, cURL.

In this recipe, we'll redo the library from the Creating a static library recipe that we covered earlier in this chapter so that it becomes a dynamic library.

Knowing how to create dynamic libraries enables you to distribute your code as easy-to-implement libraries for other developers to use.

Getting ready

For this recipe, you'll need the two convert.c and convert.h files from the Creating a static library recipe earlier in this chapter. You'll also need the GCC compiler.

How to do it…

Here, we make a dynamic library out of convert.c from the Creating a static library recipe earlier in this chapter:

  1. First of all, let's remove the object file and the old static...