CMAKE_TOOLCHAIN_FILE

Added in version 3.21.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

The CMAKE_TOOLCHAIN_FILE environment variable specifies a default value for the 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 CMAKE_TOOLCHAIN_FILE.