1The value of this variable should be set prior to the first 2:command:`project` or :command:`enable_language` command invocation 3because it may influence configuration of the toolchain and flags. 4It is intended to be set locally by the user creating a build tree. 5This variable should be set as a ``CACHE`` entry (or else CMake may 6remove it while initializing a cache entry of the same name). 7 8Despite the ``OSX`` part in the variable name(s) they apply also to 9other SDKs than macOS like iOS, tvOS, or watchOS. 10 11This variable is ignored on platforms other than Apple. 12