std::is_enum
Defined in header <type_traits> | ||
|---|---|---|
template< class T > struct is_enum; | (since C++11) |
std::is_enum is a UnaryTypeTrait.
Checks whether T is an enumeration type. Provides the member constant value which is equal to true, if T is an enumeration type. Otherwise, value is equal to false.
The behavior of a program that adds specializations for std::is_enum or std::is_enum_v is undefined.
Template parameters
| T | - | a type to check |
Helper variable template
template< class T > inline constexpr bool is_enum_v = is_enum<T>::value; | (since C++17) |
Inherited from std::integral_constant
Member constants
| value
[static] | true if T is an 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> |
Example
#include <type_traits>
struct A { enum E {}; };
static_assert(std::is_enum_v<A> == false);
static_assert(std::is_enum_v<A::E> == true);
enum E {};
static_assert(std::is_enum_v<E> == true);
enum class Ec : int {};
static_assert(std::is_enum_v<Ec> == true);
static_assert(std::is_enum_v<int> == false);
int main() {}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++23) | checks if a type is a scoped enumeration type (class template) |
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