struct problems.

I have a header file and a normal c-file. When trying to compile them I get a few errors. I don't know what to do about them. Here are the files :

Code:

//H_linked_list.h : 
struct ListNode;

typedef struct _List {
	ListNode *first;
	ListNode *last;
	int size;
} List;

List initList();
void freeList (List *list);
void addNode (List *list, void *data);
void freeNode (List *list, void *data);
void *getData (ListNode *node);
ListNode *next (ListNode *node);
ListNode *prev (ListNode *node)
ListNode *getFirst (List *list);
ListNode *getLast (List *list);
int getSize (List *list);

Code:

//H_linked_list.c : 
#include "H_linked_list.h"

typedef struct _ListNode {
	ListNode *next;
	ListNode *prev;
	void *data;
} ListNode;

int main(){
	return 0;
}

Code:

typedef struct _List {
	struct _List *first;
	struct _List *last;
	int size;
} List;

You must use the tag name of the struct when referring to itself