Book Image

Embedded Linux Development Using Yocto Project - Third Edition

By : Otavio Salvador, Daiane Angolini
Book Image

Embedded Linux Development Using Yocto Project - Third Edition

By: Otavio Salvador, Daiane Angolini

Overview of this book

The Yocto Project is the industry standard for developing dependable embedded Linux projects. It stands out from other frameworks by offering time-efficient development with enhanced reliability and robustness. With Embedded Linux Development Using Yocto Project, you’ll acquire an understanding of Yocto Project tools, helping you perform different Linux-based tasks. You’ll gain a deep understanding of Poky and BitBake, explore practical use cases for building a Linux subsystem project, employ Yocto Project tools available for embedded Linux, and uncover the secrets of SDK, recipe tool, and others. This new edition is aligned with the latest long-term support release of the aforementioned technologies and introduces two new chapters, covering optimal emulation in QEMU for faster product development and best practices. By the end of this book, you’ll be well-equipped to generate and run an image for real hardware boards. You’ll gain hands-on experience in building efficient Linux systems using the Yocto Project.
Table of Contents (20 chapters)

Understanding the scope of a variable

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

  • Variables defined in configuration files are global to every recipe, also referred to as configuration metadata. 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 have recipe visibility scope that is local to the specific recipe only during the execution of its tasks.