Question

I’m not really familiar with C and when I was trying to use C to build a linked list, I ran into a little problem and would like to have someone clarify it for me.

Here’s my code so far:

typedef struct {
struct dlinkNode_t *next;
struct dlinkNode_t *prev;
void *value;
} dlinkNode_t;

dlinkNode_t* getNext(dlinkNode_t *ptr){
/**return the next node of the node pointed by ptr. Return NULL if next element*/
return ptr->next;

When I tried to compile it I got the following warning:

"warning: return from incompatible pointer type"

I defined dlinkNode_t to be the type of my linked list’s node, and each node has 2 pointers pointing forward and backward. Should I define the return type of getNext to be:

struct dlinkNode_t*

But this seems to violate the purpose of typedef, because I want to define dlinkNode as a new type. Any help would be good.

Thank you!

Answer 1

Hope this helps.. struct must have name when you are using same struct pointer inside it ….

typedef struct dlinkNode {
struct dlinkNode *next;
struct dlinkNode *prev;
void *value;
} dlinkNode_t;

dlinkNode_t* getNext(dlinkNode_t *ptr){
/**return the next node of the node pointed by ptr. Return NULL if next element*/
return ptr->next;