# CMAKE_GENERATOR_PLATFORM

New in version 3.1.

Generator-specific target platform specification provided by user.

Some CMake generators support a target platform name to be given to the native build system to choose a compiler toolchain. If the user specifies a platform name (e.g. via the `cmake -A` option or via the `CMAKE_GENERATOR_PLATFORM` environment variable) the value will be available in this variable.

The value of this variable should never be modified by project code. A toolchain file specified by the `CMAKE_TOOLCHAIN_FILE` variable may initialize `CMAKE_GENERATOR_PLATFORM`. Once a given build tree has been initialized with a particular value for this variable, changing the value has undefined behavior.

Platform specification is supported only on specific generators:

- For Visual Studio Generators with VS 2005 and above this specifies the target architecture.

- For `Green Hills MULTI` this specifies the target architecture.

See native build system documentation for allowed platform names.

## Visual Studio Platform Selection

On Visual Studio Generators the selected platform name is provided in the `CMAKE_VS_PLATFORM_NAME` variable.