The `tmp != head` comparion is UB because `head` is a dangling pointer after the first loop iteration, right?
void free_circularly_linked_list(struct node *head) {
struct node *tmp = head->next;
while (1) {
if (tmp == head) {
/* Has to be a separate case since even assigning
* a dangling pointer is UB I believe? */
free(tmp);
break;
} else {
struct node *next = tmp->next;
free(tmp);
tmp = next;
}
}
} void free_circularly_linked_list(struct node *head)
{
struct node *a = head->next;
while (a != head) {
struct node *b = a->next;
free(a);
a = b;
}
free(head);
}
Let's say head value is "10" and the memory at "10" is {..., next: "10"}
After the first iteration we will have:
Head: "10" Next: "10" Temp: "10"
With "10" pointing to freed memory. But why do we care? We are not dereferencing it, are we?
(I think I am missing something very obvious)