What are the uses of the type `std::nullptr_t`?

Question

I learned that nullptr, in addition to being convertible to any pointer type (but not to any integral type) also has its own type std::nullptr_t. S

Answer 1

If more than one overload accepts a pointer type, an overload for std::nullptr_t is necessary to accept a nullptr argument. Without the std::nullptr_t overload, it would be ambiguous which pointer overload should be selected when passed nullptr.

Example:

void f(int *intp)
{
    // Passed an int pointer
}

void f(char *charp)
{
    // Passed a char pointer
}

void f(std::nullptr_t nullp)
{
    // Passed a null pointer
}