CMAKE_TOOLCHAIN_FILE -------------------- .. versionadded:: 3.21 .. include:: include/ENV_VAR.rst The ``CMAKE_TOOLCHAIN_FILE`` environment variable specifies a default value for the :variable:`CMAKE_TOOLCHAIN_FILE` variable when there is no explicit configuration given on the first run while creating a new build tree. On later runs in an existing build tree the value persists in the cache as :variable:`CMAKE_TOOLCHAIN_FILE`.
