# CXX_STANDARD

New in version 3.1.

The C++ standard whose features are requested to build this target.

This property specifies the C++ standard whose features are requested to build this target. For some compilers, this results in adding a flag such as `-std=gnu++11` to the compile line. For compilers that have no notion of a standard level, such as Microsoft Visual C++ before 2015 Update 3, this has no effect.

Supported values are `98`, `11`, `14`, `17`, and `20`.

If the value requested does not result in a compile flag being added for the compiler in use, a previous standard flag will be added instead. This means that using:

    set_property(TARGET tgt PROPERTY CXX_STANDARD 11)

with a compiler which does not support `-std=gnu++11` or an equivalent flag will not result in an error or warning, but will instead add the `-std=gnu++98` flag if supported. This “decay” behavior may be controlled with the `CXX_STANDARD_REQUIRED` target property. Additionally, the `CXX_EXTENSIONS` target property may be used to control whether compiler-specific extensions are enabled on a per-target basis.

See the `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 `CMAKE_CXX_STANDARD` variable if it is set when a target is created.