std::is_enum - cppreference.com (original) (raw)
| | | | | ------------------------------------- | | ------------- | | 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.
If the program adds specializations for std::is_enum or std::is_enum_v, the behavior is undefined.
Contents
[edit] Template parameters
[edit] Helper variable template
| template< class T > constexpr bool is_enum_v = is_enum<T>::value; | | (since C++17) | | ----------------------------------------------------------------------- | | ------------- |
Inherited from std::integral_constant
Member constants
| | true if T is an enumeration type, false otherwise (public static member constant) | | ------------------------------------------------------------------------------------ |
Member functions
| | converts the object to bool, returns value (public member function) | | ---------------------------------------------------------------------- | | | returns value (public member function) |
Member types
[edit] Example
#include struct A { enum E {}; }; static_assert(std::is_enum_v == false); static_assert(std::is_enum_v<A::E> == true); enum E {}; static_assert(std::is_enum_v == true); enum class Ec : int {}; static_assert(std::is_enum_v == true); static_assert(std::is_enum_v == false); int main() {}