home | help 
std::is_scoped_enum(3)	       C++ Standard Libary	  std::is_scoped_enum(3)

NAME
     std::is_scoped_enum - std::is_scoped_enum

Synopsis
	Defined in header <type_traits>
	template< class T >		 (since C++23)
	struct is_scoped_enum;

	std::is_scoped_enum is a UnaryTypeTrait.

	Checks	whether T is a scoped enumeration type. Provides the member con-
     stant value
	which is equal to true, if T is a scoped  enumeration  type.  Otherwise,
     value is equal
	to false.

	If the program adds specializations for std::is_scoped_enum or
	std::is_scoped_enum_v, the behavior is undefined.

Template parameters
	T - a type to check

	Helper variable template

	template<		    class		    T		       >
     (since C++23)
	inline constexpr bool is_scoped_enum_v = is_scoped_enum<T>::value;

     Inherited from std::integral_constant

Member constants
	value	 true if T is a scoped enumeration type, false otherwise
	[static] (public static member constant)

Member functions
	operator bool converts the object to bool, returns value
		      (public member function)
	operator()    returns value
	(C++14)       (public member function)

Member types
	Type	   Definition
	value_type bool
	type	   std::integral_constant<bool, value>

Notes
	   Feature-test macro	  Value    Std	       Feature
	__cpp_lib_is_scoped_enum 202011L (C++23) std::is_scoped_enum

Possible implementation
	template<typename E>
	struct is_scoped_enum : std::bool_constant<requires
	{
	    requires std::is_enum_v<E>;
	    requires !std::is_convertible_v<E, std::underlying_type_t<E>>;
	}>
	{};

Example
     // Run this code

      #include <type_traits>

      class A {};

      enum E {};

      enum struct Es { oz };

      enum class Ec : int {};

      int main()
      {
	  static_assert(std::is_scoped_enum_v<A> == false);
	  static_assert(std::is_scoped_enum_v<E> == false);
	  static_assert(std::is_scoped_enum_v<Es> == true);
	  static_assert(std::is_scoped_enum_v<Ec> == true);
	  static_assert(std::is_scoped_enum_v<int> == false);
      }

See also
	is_integral   checks if a type is an integral type
	(C++11)       (class template)
	is_arithmetic checks if a type is an arithmetic type
	(C++11)       (class template)
	is_scalar     checks if a type is a scalar type
	(C++11)       (class template)
	is_enum       checks if a type is an enumeration type
	(C++11)       (class template)

http://cppreference.com 	   2024.06.10		  std::is_scoped_enum(3)
home | help