< cpp‎ | types
Metaprogramming library
Type traits
Type categories
Type properties
(C++11)(until C++20)
(C++11)(deprecated in C++20)
Type trait constants
Supported operations
Relationships and property queries
Type modifications
Type transformations
(C++11)(deprecated in C++23)
(C++11)(deprecated in C++23)

(C++11)(until C++20)(C++17)
Compile-time rational arithmetic
Compile-time integer sequences
Defined in header <type_traits>
template< class T >
struct is_rvalue_reference;
(since C++11)

Checks whether T is an rvalue reference type. Provides the member constant value which is equal to true, if T is an rvalue reference type. Otherwise, value is equal to false.

The behavior of a program that adds specializations for is_rvalue_reference or is_rvalue_reference_v (since C++17) is undefined.


[edit] Template parameters

T - a type to check

[edit] Helper variable template

template< class T >
inline constexpr bool is_rvalue_reference_v = is_rvalue_reference<T>::value;
(since C++17)

Inherited from std::integral_constant

Member constants

true if T is an rvalue reference type , false otherwise
(public static member constant)

Member functions

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

Member types

Type Definition
value_type bool
type std::integral_constant<bool, value>

[edit] Possible implementation

template <class T> struct is_rvalue_reference      : std::false_type {};
template <class T> struct is_rvalue_reference<T&&> : std::true_type {};

[edit] Example

#include <type_traits>
class A {};
int main()
    static_assert( not std::is_rvalue_reference_v<A> );
    static_assert( not std::is_rvalue_reference_v<A&> );
    static_assert(     std::is_rvalue_reference_v<A&&> );
    static_assert( not std::is_rvalue_reference_v<int> );
    static_assert( not std::is_rvalue_reference_v<int&> );
    static_assert(     std::is_rvalue_reference_v<int&&> );

[edit] See also

checks if a type is an lvalue reference
(class template) [edit]
checks if a type is either an lvalue reference or rvalue reference
(class template) [edit]