From cppreference.com
template<classT>structis_enum;(since C++11)std::is_enum is a
.
Checks whether T is an
. 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.
Template parameters
T - a type to check Helper variable template
template<classT>constexprboolis_enum_v=is_enum<T>::value;(since C++17)Inherited from
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_typebooltypestd::integral_constant<bool,value>Example
Run this code
#include<type_traits>structA{enumE{e};};static_assert(!std::is_enum_v<A>);static_assert(std::is_enum_v<A::E>);static_assert(std::is_enum_v<decltype(A::E::e)>);enumE{};static_assert(std::is_enum_v<E>);static_assert(std::is_enum_v<constE>,"Constness is ignored");static_assert(!std::is_enum_v<E&>,"References matter");enumclassE1:int{e};static_assert(std::is_enum_v<E1>);static_assert(std::is_enum_v<decltype(E1::e)>);static_assert(!std::is_enum_v<int>);enumclassE2;static_assert(std::is_enum_v<E2>,"Forward-declared scoped enum");enumclassE3:char;static_assert(std::is_enum_v<E3>,"Forward-declared scoped enum with explicit base type");intmain(){}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)
(C++26)
checks if reflection represents an
(function)
(C++26)
checks if reflected type is an enumeration type
(function)