C: transitive (double) assignments

Question

I have used such construct in C:

list->head = list->tail = NULL;

and now I consider whether this really mean what I suppose.

<

Answer 1

Neither of them. It mean

list->tail = NULL;
list->head = list->tail;

1 is incorrect because in case the type of list->tail is not a pointer, it may yield different result because the value will be converted to the type of the destination of the assignment.

The order of two statements in 2 is incorrect.