CMAKE_SYSTEM_PROCESSOR — CMake 4.2.6 Documentation

# CMAKE_SYSTEM_PROCESSOR

When not cross-compiling, this variable has the same value as the `CMAKE_HOST_SYSTEM_PROCESSOR` variable. In many cases, this will correspond to the target architecture for the build, but this is not guaranteed. (E.g. on Windows, the host may be `AMD64` even when using a MSVC `cl` compiler with a 32-bit target.)

When cross-compiling, a `CMAKE_TOOLCHAIN_FILE` should set the `CMAKE_SYSTEM_PROCESSOR` variable to match target architecture that it specifies (via `CMAKE_<LANG>_COMPILER` and perhaps `CMAKE_<LANG>_COMPILER_TARGET`).