FASTBuild

.. versionadded:: 4.2

Generates a fbuild.bff file, which can be used to build the project with FASTBuild <https://www.fastbuild.org/docs/home.html>_.

Usage

Specify the generator when invoking :manual:cmake(1):

.. code-block:: shell

cmake [<options>] -G FASTBuild -B <path-to-build> [-S <path-to-source>]

This writes a FASTBuild configuration file named fbuild.bff into <path-to-build>.

.. note::

This generator also produces IDE project files for Visual Studio and Xcode, which are placed under:

• <path-to-build>/VisualStudio – Visual Studio solution and projects
• <path-to-build>/XCode – Xcode workspace and projects

These IDE files can be generated by building xcode or solution targets and will build using FASTBuild as the backend.

Caching

To enable FASTBuild caching, set the cache path using the :variable:CMAKE_FASTBUILD_CACHE_PATH variable or the FASTBUILD_CACHE_PATH environment variable.

Then build with the -cache flag:

.. code-block:: console

cmake --build <path-to-build> -- -cache

Compiler Behavior Variables

The following variables control how compiler nodes are emitted in the generated fbuild.bff. These settings may affect build determinism, debug info paths, include handling, and compiler argument formatting:

• :variable:CMAKE_FASTBUILD_ALLOW_RESPONSE_FILE
• :variable:CMAKE_FASTBUILD_CLANG_GCC_UPDATE_XLANG_ARG
• :variable:CMAKE_FASTBUILD_CLANG_REWRITE_INCLUDES
• :variable:CMAKE_FASTBUILD_COMPILER_EXTRA_FILES
• :variable:CMAKE_FASTBUILD_FORCE_RESPONSE_FILE
• :variable:CMAKE_FASTBUILD_SOURCE_MAPPING
• :variable:CMAKE_FASTBUILD_USE_DETERMINISTIC_PATHS
• :variable:CMAKE_FASTBUILD_USE_LIGHTCACHE
• :variable:CMAKE_FASTBUILD_USE_RELATIVE_PATHS

Configuration Variables

The following variables can be used to configure this generator:

• :variable:CMAKE_FASTBUILD_CACHE_PATH
• :variable:CMAKE_FASTBUILD_CAPTURE_SYSTEM_ENV
• :variable:CMAKE_FASTBUILD_ENV_OVERRIDES
• :variable:CMAKE_FASTBUILD_IDE_ARGS
• :variable:CMAKE_FASTBUILD_TRACK_BYPRODUCTS_AS_OUTPUT
• :variable:CMAKE_FASTBUILD_VERBOSE_GENERATOR

Target Properties

The following target properties can be used to fine-tune behavior on a per-target basis:

• :prop_tgt:FASTBUILD_CACHING – disables caching for a specific target.
• :prop_tgt:FASTBUILD_DISTRIBUTION – disables distributed compilation for a specific target.

Notes

• This generator does not support directories as outputs of custom commands. If you do specify a directory as an output, it should be marked with the SYMBOLIC property to avoid incorrect behavior.
• It is highly advised to use custom commands with only one output. If multiple outputs are specified, the generator will emit an additional rule to check the outputs at build time. This adds overhead and is necessary because FASTBuild natively supports only a single output per custom step.

Example

.. code-block:: shell

cmake [<options>] -G FASTBuild -B <path-to-build> -DCMAKE_BUILD_TYPE=Release cmake --build <path-to-build> --target my_app

This generates fbuild.bff in <path-to-build> and uses FASTBuild to build the my_app target.

See Also

• :manual:cmake-generators(7)
• FASTBuild Documentation <https://www.fastbuild.org/docs/documentation.html>_