What is the really pointing to?

[Pete Schmitt]

What is the null pointer really pointing to?

If I define the following:

struct entry
{
	int	value;
	struct entry *next;
};

struct entry n1, n2, n3, *list_pointer = &n1;

n1.next = &n2;
n2.next = &n3;
n3.next = (struct entry *) 0;   /* <-- what is this pointing to, address 0? */