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std::is_rvalue_reference

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Revision as of 17:03, 2 November 2012 by P12bot (Talk | contribs)

 
 
 
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is_rvalue_reference
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Template:ddcl list begin <tr class="t-dsc-header">

<td>
Defined in header <type_traits>
</td>

<td></td> <td></td> <tr class="t-dcl-sep"><td></td><td></td><td></td></tr>

<tr class="t-dcl ">

<td >
template< class T >
struct is_rvalue_reference;
</td>

<td class="t-dcl-nopad"> </td> <td > (since C++11) </td> </tr> Template:ddcl list end

If T is an rvalue reference type, provides the member constant value equal true. For any other type, value is false.

Contents

Inherited from std::integral_constant

Member constants

value
[static]
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)

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

#include <iostream>
#include <type_traits>
 
class A {};
 
int main() 
{
    std::cout << std::boolalpha;
    std::cout << std::is_rvalue_reference<A>::value << '\n';
    std::cout << std::is_rvalue_reference<A&>::value << '\n';
    std::cout << std::is_rvalue_reference<A&&>::value << '\n';
    std::cout << std::is_rvalue_reference<int>::value << '\n';
    std::cout << std::is_rvalue_reference<int&>::value << '\n';
    std::cout << std::is_rvalue_reference<int&&>::value << '\n';
}

Output:

false
false
true
false
false
true

See also

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