| Boolean describing whether the value of :prop_tgt:`CXX_STANDARD` is a requirement. |
| If this property is set to ``ON``, then the value of the |
| :prop_tgt:`CXX_STANDARD` target property is treated as a requirement. If this |
| property is ``OFF`` or unset, the :prop_tgt:`CXX_STANDARD` target property is |
| treated as optional and may "decay" to a previous standard if the requested is |
| not available. For compilers that have no notion of a standard level, such as |
| MSVC 1800 (Visual Studio 2013) and lower, this has no effect. |
| 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_STANDARD_REQUIRED` variable if it is set when a |
| Alternatively, see :ref:`Requiring Language Standards`. |
