c - change pointer passed by value

Question

I have given a function foo(struct node *n) where n is the head node in a linked list. Now foo should change n s.t. it points to the end of the list.

But is this possible with this function signature?

Assuming t is the pointer to the end of the list:

• n = t won't work because the pointer is passed by value.
• *n = *t won't work because I would overwrite the head of the list.

Did I miss something?

Answer 1

You would need to use a pointer to a pointer:

foo(struct node **n) 

To change what n points to, you do:

*n = t;