Specify the minimum version of the target platform (e.g. macOS or iOS) on which the target binaries are to be deployed. CMake uses this variable value for the -mmacosx-version-min flag or their respective target platform equivalents. For older Xcode versions that shipped multiple macOS SDKs this variable also helps to choose the SDK in case CMAKE_OSX_SYSROOT is unset.

If not set explicitly the value is initialized by the MACOSX_DEPLOYMENT_TARGET environment variable, if set, and otherwise computed based on the host platform.

The value of this variable should be set prior to the first project() or enable_language() command invocation because it may influence configuration of the toolchain and flags. It is intended to be set locally by the user creating a build tree.

Despite the OSX part in the variable name(s) they apply also to other SDKs than macOS like iOS, tvOS, or watchOS.

This variable is ignored on platforms other than Apple.