Book Image

Embedded Linux Development with Yocto Project

By : Otavio Salvador
Book Image

Embedded Linux Development with Yocto Project

By: Otavio Salvador

Overview of this book

A practical tutorial guide which introduces you to the basics of Yocto Project, and also helps you with its real hardware use to boost your Embedded Linux-based project. If you are an embedded systems enthusiast and willing to learn about compelling features offered by the Yocto Project, then this book is for you. With prior experience in the embedded Linux domain, you can make the most of this book to efficiently create custom Linux-based systems.
Table of Contents (17 chapters)
15
A. References
16
Index

Understanding the variables scope


The BitBake metadata has thousands of variables, but the scope where these variables are available depends on where it is defined. Basically, there are two kinds of variables as follows:

  • Variables defined in configuration files are global to every recipe. The parsing order of the main configuration files is shown as follows:

    • build/conf/local.conf

    • <layer>/conf/machines/<machine>.conf

    • <layer>/conf/distro/<distro>.conf

  • Variables defined within recipe files are local to the specific recipe only during the execution of its tasks.