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std::nullptr_t

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Defined in header <cstddef>
typedef decltype(nullptr) nullptr_t;
(dal C++11)
std::nullptr_t è il tipo di puntatore nullo letterale, nullptr.
Original:
std::nullptr_t is the type of the null pointer literal, nullptr.
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[modifica] Esempio

Se due o più sovraccarichi accettare diversi tipi di puntatore, un sovraccarico per std::nullptr_t è necessario accettare un argomento puntatore nullo .
Original:
If two or more overloads accept different pointer types, an overload for std::nullptr_t is necessary to accept a null pointer argument.
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#include <cstddef>
#include <iostream>
 
void f(int* pi)
{
   std::cout << "Pointer to integer overload\n";
}
 
void f(double* pd)
{
   std::cout << "Pointer to double overload\n";
}
 
void f(std::nullptr_t nullp)
{
   std::cout << "null pointer overload\n";
}
 
int main()
{
    int* pi; double* pd;
 
    f(pi);
    f(pd);
    f(nullptr);  // would be ambiguous without void f(nullptr_t)
    // f(NULL);  // ambiguous overload: all three functions are candidates
}

Output:

Pointer to integer overload
Pointer to double overload
null pointer overload

[modifica] Vedi anche

nullptr
il puntatore letterale che specifica un valore nullo (C++11) valore del puntatore
Original:
the pointer literal which specifies a null pointer value (C++11)
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[edit]
implementazione definita puntatore nullo costante
Original:
implementation-defined null pointer constant
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(macro costante) [edit]