std::result_of - cppreference.com

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Definido no cabeçalho `<type_traits>`

`template< class > class result_of; //not defined`	(1)	(desde C++11)

`template< class F, class... ArgTypes > class result_of<F(ArgTypes...)>;`	(2)	(desde C++11)

Deduz o tipo de retorno de uma expressão chamada de função em tempo de compilação.

Original:

Deduces the return type of a function call expression at compile time.

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Tipos de membro


Tipo de membro Original: Member type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.	Definition

`type`	o tipo de retorno da função se `F` chamado com o `ArgTypes...` argumentos Original: the return type of the function `F` if called with the arguments `ArgTypes...` The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Possível implementação

template<class>
struct result_of;

template<class F, class... ArgTypes>
struct result_of<F(ArgTypes...)>
{
    typedef decltype(
                     std::declval<F>()(std::declval<ArgTypes>()...)
                    ) type;
};

Exemplo

struct S {
    double operator()(char, int&);
};

int main()
{
    std::result_of<S(char, int&)>::type f = 3.14; // f has type double
}

Veja também


	obtém o tipo de expressão em contexto não avaliada Original: obtains the type of expression in unevaluated context The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função) [edit]