std::is_reference
De cppreference.com
<metanoindex/>
<tbody> </tbody>| Definido no cabeçalho <type_traits>
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template< class T > struct is_reference; |
(desde C++11) | |
Se
T é um tipo de referência (lvalue referência ou rvalue referência), fornece o membro constante value true igual. Para qualquer outro tipo, é value false.Original:
If
T is a reference type (lvalue reference or rvalue reference), provides the member constant value equal true. For any other type, value is false.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
You can help to correct and verify the translation. Click here for instructions.
Herdado de std::integral_constant
Member constants
value [estática] |
true se T is a reference type , false contrário Original: true if T is a reference type , false otherwise The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (membro estático público constante) |
Member functions
operator bool |
converte o objeto em bool, retorna value Original: converts the object to bool, returns value The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) |
Member types
Tipo
Original: Type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Definition |
value_type
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bool
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type
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std::integral_constant<bool, value>
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Possível implementação
template <class T> struct is_reference : std::false_type {};
template <class T> struct is_reference<T&> : std::true_type {};
template <class T> struct is_reference<T&&> : std::true_type {};
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Exemplo
#include <iostream>
#include <type_traits>
class A {};
int main()
{
std::cout << std::boolalpha;
std::cout << std::is_reference<A>::value << '\n';
std::cout << std::is_reference<A&>::value << '\n';
std::cout << std::is_reference<A&&>::value << '\n';
std::cout << std::is_reference<int>::value << '\n';
std::cout << std::is_reference<int&>::value << '\n';
std::cout << std::is_reference<int&&>::value << '\n';
}
Saída:
false
true
true
false
true
true