| .. _apps_overview: |
| |
| Application Overview |
| #################### |
| |
| A Zephyr application is a collection of user-supplied files that can be built |
| into an application image that executes on a board. |
| |
| Each application resides in a distinct directory created by the developer. |
| The directory has the following structure. |
| |
| * **Application source code files**: An application typically provides one |
| or more application-specific files, written in C or assembly language. These |
| files are usually located in a sub-directory called :file:`src`. |
| |
| * **Kernel configuration files**: An application typically provides |
| a configuration file (:file:`.conf`) that specifies values for one or more |
| kernel configuration options. If omitted, the application's existing kernel |
| configuration option values are used; if no existing values are provided, |
| the kernel's default configuration values are used. |
| |
| * **Makefile**: This file typically contains a handful of lines that tell |
| the build system where to find the files mentioned above, as well as |
| the desired target board configuration. |
| |
| Once the application has been defined, it can be built with a single command. |
| The results of the build process are located in a sub-directory |
| called :file:`outdir/BOARD`. This directory contains the files generated |
| by the build process, the most notable of which are listed below. |
| |
| * The :file:`.config` file that contains the configuration settings |
| used to build the application. |
| |
| * The various object files (:file:`.o` files and :file:`.a` files) containing |
| custom-built kernel and application-specific code. |
| |
| * The :file:`zephyr.elf` file that contains the final application image. |
