| CMAKE_TOOLCHAIN_FILE | |
| -------------------- | |
| .. versionadded:: 3.21 | |
| .. include:: ENV_VAR.txt | |
| 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`. |