Error 'a value of type “X *” cannot be assigned to an entity of type “X *”' when using typedef struct

Question

Here is the struct I am using for the nodes...

typedef struct
{
    struct Node* next;
    struct Node* previous;
    void* data;
} Node;

and h

Answer 1

Similar to Deepu's answer, but a version that will let your code compile. Change your struct to the following:

typedef struct Node // <-- add "Node"
{
    struct Node* next;
    struct Node* previous;
    void* data;
}Node; // <-- Optional

void linkNodes(Node* first, Node* second)
{    
    if (first != NULL)
        first->next = second;

    if (second != NULL)
        second->previous = first;
}

Answer 2

I think the problem is there is no struct called Node, there is only a typedef. Try

 typedef struct Node { ....

Answer 3

Defining typedef of struct in C is best done before the struct declaration itself.

typedef struct Node Node; // forward declaration of struct and typedef

struct Node
{
    Node* next;          // here you only need to use the typedef, now
    Node* previous;
    void* data;
};