std::is_scoped_enum
From cppreference.com
| Defined in header <type_traits>
|
||
| template< class T > struct is_scoped_enum; |
(since C++23) | |
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) | |
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
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
| (C++11) |
checks if a type is an integral type (class template) |
| (C++11) |
checks if a type is an arithmetic type (class template) |
| (C++11) |
checks if a type is a scalar type (class template) |
| (C++11) |
checks if a type is an enumeration type (class template) |