std::nullptr_t — cppreference.com

Original:

std::nullptr_t is the type of the null pointer literal, nullptr.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Si deux ou plusieurs surcharges accepter types de pointeurs différents, une surcharge pour std::nullptr_t est nécessaire d'accepter un argument pointeur nul .

#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
}

Pointer to integer overload
Pointer to double overload
null pointer overload