CXX_EXTENSIONS -------------- .. versionadded:: 3.1 Boolean specifying whether compiler specific extensions are requested. This property specifies whether compiler specific extensions should be used. For some compilers, this results in adding a flag such as ``-std=gnu++11`` instead of ``-std=c++11`` to the compile line. This property is ``ON`` by default. The basic C++ standard level is controlled by the :prop_tgt:`CXX_STANDARD` target property. See the :manual:`cmake-compile-features(7)` manual for information on compile features and a list of supported compilers. This property is initialized by the value of the :variable:`CMAKE_CXX_EXTENSIONS` variable if set when a target is created and otherwise by the value of :variable:`CMAKE_CXX_EXTENSIONS_DEFAULT _EXTENSIONS_DEFAULT>` (see :policy:`CMP0128`).