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ragingcorgi
ragingcorgi

Reputation: 3468

return from incompatible pointer type warning in C

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!

Upvotes: 0

Views: 424

Answers (2)

Gabriele Petronella
Gabriele Petronella

Reputation: 108101

Change it to

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

Upvotes: 1

Adeel Ahmed
Adeel Ahmed

Reputation: 1601

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;

Upvotes: 3

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