The variations are:

These properties specify whether compiler-specific extensions are requested.

These properties are initialized by the value of the CMAKE_<LANG>_EXTENSIONS variable if it is set when a target is created and otherwise by the value of CMAKE_<LANG>_EXTENSIONS_DEFAULT (see CMP0128).

For supported CMake versions see the respective pages. To control language standard versions see <LANG>_STANDARD.

See the cmake-compile-features(7) manual for information on compile features and a list of supported compilers.