# CMAKE_SYSTEM_NAME

The name of the operating system for which CMake is to build. See the `CMAKE_SYSTEM_VERSION` variable for the OS version.

Note that `CMAKE_SYSTEM_NAME` is not set to anything by default when running in script mode, since it’s not building anything.

## System Name for Host Builds

`CMAKE_SYSTEM_NAME` is by default set to the same value as the `CMAKE_HOST_SYSTEM_NAME` variable so that the build targets the host system.

## System Name for Cross Compiling

`CMAKE_SYSTEM_NAME` may be set explicitly when first configuring a new build tree in order to enable cross compiling. In this case the `CMAKE_SYSTEM_VERSION` variable must also be set explicitly.