README.md - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 [![CMock Unit Tests](https://github.com/FreeRTOS/FreeRTOS-Kernel/actions/workflows/unit-tests.yml/badge.svg?branch=main&event=push)](https://github.com/FreeRTOS/FreeRTOS-Kernel/actions/workflows/unit-tests.yml?query=branch%3Amain+event%3Apush+workflow%3A%22CMock+Unit+Tests%22++)
 [![codecov](https://codecov.io/gh/FreeRTOS/FreeRTOS-Kernel/badge.svg?branch=main)](https://codecov.io/gh/FreeRTOS/FreeRTOS-Kernel)

 ## Getting started

 This repository contains FreeRTOS kernel source/header files and kernel
 ports only. This repository is referenced as a submodule in
 [FreeRTOS/FreeRTOS](https://github.com/FreeRTOS/FreeRTOS)
 repository, which contains pre-configured demo application projects under
 ```FreeRTOS/Demo``` directory.

 The easiest way to use FreeRTOS is to start with one of the pre-configured demo
 application projects.  That way you will have the correct FreeRTOS source files
 included, and the correct include paths configured. Once a demo application is
 building and executing you can remove the demo application files, and start to
 add in your own application source files.  See the
 [FreeRTOS Kernel Quick Start Guide](https://www.FreeRTOS.org/FreeRTOS-quick-start-guide.html)
 for detailed instructions and other useful links.

 Additionally, for FreeRTOS kernel feature information refer to the
 [Developer Documentation](https://www.FreeRTOS.org/features.html),
 and [API Reference](https://www.FreeRTOS.org/a00106.html).

 Also for contributing and creating a Pull Request please refer to
 [the instructions here](.github/CONTRIBUTING.md#contributing-via-pull-request).

 ### Getting help

 If you have any questions or need assistance troubleshooting your FreeRTOS project,
 we have an active community that can help on the
 [FreeRTOS Community Support Forum](https://forums.freertos.org).

 ## To consume FreeRTOS-Kernel

 ### Consume with CMake

 If using CMake, it is recommended to use this repository using FetchContent.
 Add the following into your project's main or a subdirectory's `CMakeLists.txt`:

 - Define the source and version/tag you want to use:

 ```cmake
 FetchContent_Declare( freertos_kernel
   GIT_REPOSITORY https://github.com/FreeRTOS/FreeRTOS-Kernel.git
   GIT_TAG        main #Note: Best practice to use specific git-hash or tagged version
 )
 ```

 In case you prefer to add it as a git submodule, do:

 ```bash
 git submodule add https://github.com/FreeRTOS/FreeRTOS-Kernel.git <path of the submodule>
 git submodule update --init
 ```

 - Add a freertos_config library (typically an INTERFACE library) The following assumes the directory structure:
   - `include/FreeRTOSConfig.h`

 ```cmake
 add_library(freertos_config INTERFACE)

 target_include_directories(freertos_config SYSTEM
 INTERFACE
     include
 )

 target_compile_definitions(freertos_config
   INTERFACE
     projCOVERAGE_TEST=0
 )
 ```

 In case you installed FreeRTOS-Kernel as a submodule, you will have to add it as a subdirectory:

 ```cmake
 add_subdirectory(${FREERTOS_PATH})
 ```

 - Configure the FreeRTOS-Kernel and make it available
   - this particular example supports a native and cross-compiled build option.

 ```cmake
 set( FREERTOS_HEAP "4" CACHE STRING "" FORCE)
 # Select the native compile PORT
 set( FREERTOS_PORT "GCC_POSIX" CACHE STRING "" FORCE)
 # Select the cross-compile PORT
 if (CMAKE_CROSSCOMPILING)
   set(FREERTOS_PORT "GCC_ARM_CA9" CACHE STRING "" FORCE)
 endif()

 FetchContent_MakeAvailable(freertos_kernel)
 ```

 - In case of cross compilation, you should also add the following to `freertos_config`:

 ```cmake
 target_compile_definitions(freertos_config INTERFACE ${definitions})
 target_compile_options(freertos_config INTERFACE ${options})
 ```

 ### Consuming stand-alone - Cloning this repository

 To clone using HTTPS:

 ```
 git clone https://github.com/FreeRTOS/FreeRTOS-Kernel.git
 ```

 Using SSH:

 ```
 git clone git@github.com:FreeRTOS/FreeRTOS-Kernel.git
 ```

 ## Repository structure

 - The root of this repository contains the three files that are common to
 every port - list.c, queue.c and tasks.c.  The kernel is contained within these
 three files.  croutine.c implements the optional co-routine functionality - which
 is normally only used on very memory limited systems.

 - The ```./portable``` directory contains the files that are specific to a particular microcontroller and/or compiler.
 See the readme file in the ```./portable``` directory for more information.

 - The ```./include``` directory contains the real time kernel header files.

 - The ```./template_configuration``` directory contains a sample `FreeRTOSConfig.h` to help jumpstart a new project.
 See the [FreeRTOSConfig.h](examples/template_configuration/FreeRTOSConfig.h) file for instructions.

 ### Code Formatting

 FreeRTOS files are formatted using the
 "[uncrustify](https://github.com/uncrustify/uncrustify)" tool.
 The configuration file used by uncrustify can be found in the
 [FreeRTOS/CI-CD-GitHub-Actions's](https://github.com/FreeRTOS/CI-CD-Github-Actions)
 [uncrustify.cfg](https://github.com/FreeRTOS/CI-CD-Github-Actions/tree/main/formatting)
 file.

 ### Line Endings

 File checked into the FreeRTOS-Kernel repository use unix-style LF line endings
 for the best compatibility with git.

 For optimal compatibility with Microsoft Windows tools, it is best to enable
 the git autocrlf feature. You can enable this setting for the current
 repository using the following command:

 ```
 git config core.autocrlf true
 ```

 ### Git History Optimizations

 Some commits in this repository perform large refactors which touch many lines
 and lead to unwanted behavior when using the `git blame` command. You can
 configure git to ignore the list of large refactor commits in this repository
 with the following command:

 ```
 git config blame.ignoreRevsFile .git-blame-ignore-revs
 ```

 ### Spelling and Formatting

 We recommend using [Visual Studio Code](https://code.visualstudio.com),
 commonly referred to as VSCode, when working on the FreeRTOS-Kernel.
 The FreeRTOS-Kernel also uses [cSpell](https://cspell.org/) as part of its
 spelling check. The config file for which can be found at [cspell.config.yaml](cspell.config.yaml)
 There is additionally a
 [cSpell plugin for VSCode](https://marketplace.visualstudio.com/items?itemName=streetsidesoftware.code-spell-checker)
 that can be used as well.
 *[.cSpellWords.txt](.github/.cSpellWords.txt)* contains words that are not
 traditionally found in an English dictionary. It is used by the spellchecker
 to verify the various jargon, variable names, and other odd words used in the
 FreeRTOS code base are correct. If your pull request fails to pass the spelling
 and you believe this is a mistake, then add the word to
 *[.cSpellWords.txt](.github/.cSpellWords.txt)*. When adding a word please
 then sort the list, which can be done by running the bash command:
 `sort -u .cSpellWords.txt -o .cSpellWords.txt`
 Note that only the FreeRTOS-Kernel Source Files, [include](include),
 [portable/MemMang](portable/MemMang), and [portable/Common](portable/Common)
 files are checked for proper spelling, and formatting at this time.
	[![CMock Unit Tests](https://github.com/FreeRTOS/FreeRTOS-Kernel/actions/workflows/unit-tests.yml/badge.svg?branch=main&event=push)](https://github.com/FreeRTOS/FreeRTOS-Kernel/actions/workflows/unit-tests.yml?query=branch%3Amain+event%3Apush+workflow%3A%22CMock+Unit+Tests%22++)
	[![codecov](https://codecov.io/gh/FreeRTOS/FreeRTOS-Kernel/badge.svg?branch=main)](https://codecov.io/gh/FreeRTOS/FreeRTOS-Kernel)

	## Getting started

	This repository contains FreeRTOS kernel source/header files and kernel
	ports only. This repository is referenced as a submodule in
	[FreeRTOS/FreeRTOS](https://github.com/FreeRTOS/FreeRTOS)
	repository, which contains pre-configured demo application projects under
	```FreeRTOS/Demo``` directory.

	The easiest way to use FreeRTOS is to start with one of the pre-configured demo
	application projects. That way you will have the correct FreeRTOS source files
	included, and the correct include paths configured. Once a demo application is
	building and executing you can remove the demo application files, and start to
	add in your own application source files. See the
	[FreeRTOS Kernel Quick Start Guide](https://www.FreeRTOS.org/FreeRTOS-quick-start-guide.html)
	for detailed instructions and other useful links.

	Additionally, for FreeRTOS kernel feature information refer to the
	[Developer Documentation](https://www.FreeRTOS.org/features.html),
	and [API Reference](https://www.FreeRTOS.org/a00106.html).

	Also for contributing and creating a Pull Request please refer to
	[the instructions here](.github/CONTRIBUTING.md#contributing-via-pull-request).

	### Getting help

	If you have any questions or need assistance troubleshooting your FreeRTOS project,
	we have an active community that can help on the
	[FreeRTOS Community Support Forum](https://forums.freertos.org).

	## To consume FreeRTOS-Kernel

	### Consume with CMake

	If using CMake, it is recommended to use this repository using FetchContent.
	Add the following into your project's main or a subdirectory's `CMakeLists.txt`:

	- Define the source and version/tag you want to use:

	```cmake
	FetchContent_Declare( freertos_kernel
	GIT_REPOSITORY https://github.com/FreeRTOS/FreeRTOS-Kernel.git
	GIT_TAG main #Note: Best practice to use specific git-hash or tagged version
	)
	```

	In case you prefer to add it as a git submodule, do:

	```bash
	git submodule add https://github.com/FreeRTOS/FreeRTOS-Kernel.git <path of the submodule>
	git submodule update --init
	```

	- Add a freertos_config library (typically an INTERFACE library) The following assumes the directory structure:
	- `include/FreeRTOSConfig.h`

	```cmake
	add_library(freertos_config INTERFACE)

	target_include_directories(freertos_config SYSTEM
	INTERFACE
	include
	)

	target_compile_definitions(freertos_config
	INTERFACE
	projCOVERAGE_TEST=0
	)
	```

	In case you installed FreeRTOS-Kernel as a submodule, you will have to add it as a subdirectory:

	```cmake
	add_subdirectory(${FREERTOS_PATH})
	```

	- Configure the FreeRTOS-Kernel and make it available
	- this particular example supports a native and cross-compiled build option.

	```cmake
	set( FREERTOS_HEAP "4" CACHE STRING "" FORCE)
	# Select the native compile PORT
	set( FREERTOS_PORT "GCC_POSIX" CACHE STRING "" FORCE)
	# Select the cross-compile PORT
	if (CMAKE_CROSSCOMPILING)
	set(FREERTOS_PORT "GCC_ARM_CA9" CACHE STRING "" FORCE)
	endif()

	FetchContent_MakeAvailable(freertos_kernel)
	```

	- In case of cross compilation, you should also add the following to `freertos_config`:

	```cmake
	target_compile_definitions(freertos_config INTERFACE ${definitions})
	target_compile_options(freertos_config INTERFACE ${options})
	```

	### Consuming stand-alone - Cloning this repository

	To clone using HTTPS:

	```
	git clone https://github.com/FreeRTOS/FreeRTOS-Kernel.git
	```

	Using SSH:

	```
	git clone git@github.com:FreeRTOS/FreeRTOS-Kernel.git
	```

	## Repository structure

	- The root of this repository contains the three files that are common to
	every port - list.c, queue.c and tasks.c. The kernel is contained within these
	three files. croutine.c implements the optional co-routine functionality - which
	is normally only used on very memory limited systems.

	- The ```./portable``` directory contains the files that are specific to a particular microcontroller and/or compiler.
	See the readme file in the ```./portable``` directory for more information.

	- The ```./include``` directory contains the real time kernel header files.

	- The ```./template_configuration``` directory contains a sample `FreeRTOSConfig.h` to help jumpstart a new project.
	See the [FreeRTOSConfig.h](examples/template_configuration/FreeRTOSConfig.h) file for instructions.

	### Code Formatting

	FreeRTOS files are formatted using the
	"[uncrustify](https://github.com/uncrustify/uncrustify)" tool.
	The configuration file used by uncrustify can be found in the
	[FreeRTOS/CI-CD-GitHub-Actions's](https://github.com/FreeRTOS/CI-CD-Github-Actions)
	[uncrustify.cfg](https://github.com/FreeRTOS/CI-CD-Github-Actions/tree/main/formatting)
	file.

	### Line Endings

	File checked into the FreeRTOS-Kernel repository use unix-style LF line endings
	for the best compatibility with git.

	For optimal compatibility with Microsoft Windows tools, it is best to enable
	the git autocrlf feature. You can enable this setting for the current
	repository using the following command:

	```
	git config core.autocrlf true
	```

	### Git History Optimizations

	Some commits in this repository perform large refactors which touch many lines
	and lead to unwanted behavior when using the `git blame` command. You can
	configure git to ignore the list of large refactor commits in this repository
	with the following command:

	```
	git config blame.ignoreRevsFile .git-blame-ignore-revs
	```

	### Spelling and Formatting

	We recommend using [Visual Studio Code](https://code.visualstudio.com),
	commonly referred to as VSCode, when working on the FreeRTOS-Kernel.
	The FreeRTOS-Kernel also uses [cSpell](https://cspell.org/) as part of its
	spelling check. The config file for which can be found at [cspell.config.yaml](cspell.config.yaml)
	There is additionally a
	[cSpell plugin for VSCode](https://marketplace.visualstudio.com/items?itemName=streetsidesoftware.code-spell-checker)
	that can be used as well.
	[.cSpellWords.txt](.github/.cSpellWords.txt) contains words that are not
	traditionally found in an English dictionary. It is used by the spellchecker
	to verify the various jargon, variable names, and other odd words used in the
	FreeRTOS code base are correct. If your pull request fails to pass the spelling
	and you believe this is a mistake, then add the word to
	[.cSpellWords.txt](.github/.cSpellWords.txt). When adding a word please
	then sort the list, which can be done by running the bash command:
	`sort -u .cSpellWords.txt -o .cSpellWords.txt`
	Note that only the FreeRTOS-Kernel Source Files, [include](include),
	[portable/MemMang](portable/MemMang), and [portable/Common](portable/Common)
	files are checked for proper spelling, and formatting at this time.