Namespaces
Variants

    std::is_scoped_enum

    From cppreference.com
     
    C++
     
    Metaprogramming library
    Type traits
    Type categories
    (C++11)
    (C++11)(DR*)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11) 
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)  
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    Type properties
    (C++11)
    (C++11)
    (C++11)
    (C++11)
    (C++14)
    (C++11)
    (C++17)
    (C++23)
    (C++11)(deprecated in C++26)
    (C++11)
    (C++11)
    (C++11)(until C++20*)
    (C++11)(deprecated in C++20)
    (C++11)
    (C++11)
    (C++20)
    (C++20)
    (C++23)
    (C++17)
    Type trait constants
    (C++11)(C++17)(C++11)(C++11)
    Metafunctions
    (C++17)
    (C++17)
    (C++17)
    Supported operations
    Relationships and property queries
    Type modifications
    (C++11)(C++11)(C++11)
    (C++11)(C++11)(C++11)
    (C++11)
    (C++11)
    Type transformations
    (C++11)(deprecated in C++23)
    (C++11)(deprecated in C++23)
    (C++11)
    (C++20)
    (C++11)(until C++20*)(C++17)

    (C++11)
    (C++11)
    (C++20)
    (C++11)
    (C++20)
    (C++11)
    (C++17)
    Compile-time rational arithmetic
    Compile-time integer sequences
    (C++14)
     
    Defined in header <type_traits>
    template< class T > struct is_scoped_enum;
    		 (since C++23)
    See More

    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

    T - a type to check

    Helper variable template

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

    Inherited from std::integral_constant

    Member constants

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

    Member functions

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

    namespace detail
{
void test_conversion(...);          // selected when E is complete and scoped
void test_conversion(int) = delete; // selected when E is complete and unscoped

template<class E>
concept is_scoped_enum_impl =
    std::is_enum_v<E> &&                        // checked first
    requires { detail::test_conversion(E{}); }; // ill-formed before overload resolution
                                                // when E is incomplete
} // namespace detail

template<class T>
struct is_scoped_enum : std::bool_constant<detail::is_scoped_enum_impl<T>> {};

    Example

    Run this code
    #include <type_traits>

static_assert(std::is_scoped_enum_v<int> == false);

class A {};
static_assert(std::is_scoped_enum_v<A> == false);

enum B { self_test = std::is_scoped_enum_v<B> };
static_assert(std::is_scoped_enum_v<B> == false);
static_assert(!self_test);

enum struct C { final, import, module };
static_assert(std::is_scoped_enum_v<C> == true);

enum class D : int { pre, post, override };
static_assert(std::is_scoped_enum_v<D> == true);

enum class E;
static_assert(std::is_scoped_enum_v<E> == true);

int main() {}

    See also

    (C++11)
    		 checks if a type is an integral type
    (class template) [edit]
    (C++11)
    		 checks if a type is an arithmetic type
    (class template) [edit]
    (C++11)
    		 checks if a type is a scalar type
    (class template) [edit]
    (C++11)
    		 checks if a type is an enumeration type
    (class template) [edit]