std:: is_scoped_enum

std::is_scoped_enum is a UnaryTypeTrait .

Checks whether T is a scoped enumeration type . Provides the member constant 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

Helper variable template

Notes

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

#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