Book Image

Mastering Embedded Linux Programming - Second Edition

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming - Second Edition

By: Chris Simmonds

Overview of this book

Embedded Linux runs many of the devices we use every day, from smart TVs to WiFi routers, test equipment to industrial controllers - all of them have Linux at their heart. Linux is a core technology in the implementation of the inter-connected world of the Internet of Things. The comprehensive guide shows you the technologies and techniques required to build Linux into embedded systems. You will begin by learning about the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. You’ll see how to create each of these elements from scratch, and how to automate the process using Buildroot and the Yocto Project. Moving on, you’ll find out how to implement an effective storage strategy for flash memory chips, and how to install updates to the device remotely once it is deployed. You’ll also get to know the key aspects of writing code for embedded Linux, such as how to access hardware from applications, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters show you how to debug your code, both in applications and in the Linux kernel, and how to profile the system so that you can look out for performance bottlenecks. By the end of the book, you will have a complete overview of the steps required to create a successful embedded Linux system.
Table of Contents (17 chapters)

Linking with libraries – static and dynamic linking

Any application you write for Linux, whether it be in C or C++, will be linked with the C library libc. This is so fundamental that you don't even have to tell gcc or g++ to do it because it always links libc. Other libraries that you may want to link with have to be explicitly named through the -l option.

The library code can be linked in two different ways: statically, meaning that all the library functions your application calls and their dependencies are pulled from the library archive and bound into your executable; and dynamically, meaning that references to the library files and functions in those files are generated in the code but the actual linking is done dynamically at runtime. You will find the code for the examples that follow in the book code archive in MELP/chapter_02/library.

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