1CMAKE_TOOLCHAIN_FILE 2-------------------- 3 4.. versionadded:: 3.21 5 6.. include:: ENV_VAR.txt 7 8The ``CMAKE_TOOLCHAIN_FILE`` environment variable specifies a default value 9for the :variable:`CMAKE_TOOLCHAIN_FILE` variable when there is no explicit 10configuration given on the first run while creating a new build tree. 11On later runs in an existing build tree the value persists in the cache 12as :variable:`CMAKE_TOOLCHAIN_FILE`. 13