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std::is_const

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is_const
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Definido no cabeçalho <type_traits>
template< class T >
struct is_const;
 (desde C++11)
Se T é um tipo const qualificado (isto é, const ou const volatile), fornece o membro constante value true igual. Para qualquer outro tipo, é value false.
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If T is a const-qualified type (that is, const, or const volatile), provides the member constant value equal true. For any other type, value is false.
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Índice

Herdado de std::integral_constant

Member constants

value
[estática]
true se T is a const-qualified type , false contrário
Original:
true if T is a const-qualified type , false otherwise
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(membro estático público constante)

Member functions

operator bool
converte o objeto em bool, retorna value
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converts the object to bool, returns value
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(função pública membro)

Member types

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

[editar] Possível implementação

template<class T> struct is_const          : std::false_type {};
template<class T> struct is_const<const T> : std::true_type {};

[editar] Exemplo

#include <iostream>
#include <type_traits>
 
int main() 
{
    std::cout << boolalpha;
    std::cout << std::is_const<int>::value << '\n';
    std::cout << std::is_const<const int>::value  << '\n';
}

Saída: 

false
true

[editar] Veja também

(C++11)
verifica se um tipo é volátil qualificado
Original:
checks if a type is volatile-qualified
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(modelo de classe) [edit]
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