C_STANDARD

.. versionadded:: 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=gnu11 to the compile line. For compilers that have no notion of a C standard level, such as Microsoft Visual C++ before VS 16.7, this property has no effect.

Supported values are:

90 C89/C90

99 C99

11 C11

17 .. versionadded:: 3.21

C17

23 .. versionadded:: 3.21

C23

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:

.. code-block:: cmake

set_property(TARGET tgt PROPERTY C_STANDARD 11)

with a compiler which does not support -std=gnu11 or an equivalent flag will not result in an error or warning, but will instead add the -std=gnu99 or -std=gnu90 flag if supported. This "decay" behavior may be controlled with the :prop_tgt:C_STANDARD_REQUIRED target property. Additionally, the :prop_tgt:C_EXTENSIONS target property may be used to control whether compiler-specific extensions are enabled on a per-target basis.

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_C_STANDARD variable if it is set when a target is created.