std::is_polymorphic - cppreference.com
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      std::is_polymorphic

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      <tbody> </tbody>
      Definido no cabeçalho <type_traits>
      template< class T > struct is_polymorphic;
      		 (desde C++11)
      Se T é uma classe polimórfica (que é, uma classe que declara ou herda pelo menos uma função virtual), fornece o membro constante value true igual. Para qualquer outro tipo, é value false.
      Original:
      If T is a polymorphic class (that is, a class that declares or inherits at least one virtual function), provides the member constant value equal true. For any other type, value is false.
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      Herdado de std::integral_constant

      Member constants

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

      Member functions

      operator bool
      converte o objeto em bool, retorna value
      Original:
      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>

      Notas

      Apenas classes polimórficas conter informação escondida RTTI o que torna possível a examinar e convertê-los com dynamic_cast.
      Original:
      Only polymorphic classes contain hidden RTTI information which makes it possible to examine and convert them with dynamic_cast.
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      Exemplo

      #include <iostream>
#include <type_traits>

struct A {
    int m;
};

struct B {
    virtual void foo();
};

struct C : B {};

int main()
{
    std::cout << std::boolalpha;
    std::cout << std::is_polymorphic<A>::value << '\n';
    std::cout << std::is_polymorphic<B>::value << '\n';
    std::cout << std::is_polymorphic<C>::value << '\n';
}

      Saída: 

      false
true
true

      Veja também