NAME¶

std::is_rvalue_reference - std::is_rvalue_reference

Synopsis¶

Defined in header <type_traits>
template< class T > (since C++11)
struct is_rvalue_reference;

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.

Template parameters¶

T - a type to check

Helper variable template

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

Inherited from std::integral_constant

Member constants¶

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

Member functions¶

operator bool converts the object to bool, returns value
(public member function)
operator() returns value
(C++14) (public member function)

Member types¶

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

Possible implementation¶

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

Example¶

// Run this code

#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&&> );
}

See also¶

is_lvalue_reference checks if a type is a lvalue reference
(C++11) (class template)
is_reference checks if a type is either a lvalue reference or rvalue
(C++11) reference
(class template)