Maybe I live in a C reality distortion field. :)
void free_circularly_linked_list(struct node *head) {
struct node *tmp = head;
do {
struct node *next = tmp->next;
free(tmp);
tmp = next;
} while (tmp != head);
}
I've written up a demo with your code, running it through several analysers:
https://gist.github.com/technion/1b12c9b4581e915241d9483c5c2...
The tl;dr here is that tis-interpreter is a fantastic new tool, as it correctly complains about this.
Edit: I also note a departure from yester-year, where every linting tool would only manage to complain about unchecked malloc() returns.
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)