structures: dereferencing pointer to incomplete type

[Adam Rinkleff]

I'm trying to make this basic 'MUD' style game to practice coding, the problem I was having was trying to have two structure types, each of which can contain a pointer to the other type. After I finally got that to compile via the forward typedef declarations, I can no longer access the structure elements and instead get the error: dereferencing pointer to incomplete type

typedef struct node Items;
typedef struct node Areas;

struct Areas{
char desc[255];
char name[255];
Items*items;
int n,s,w,e,u,d;
}; 

extern struct Areas a[1000];

struct Items{
char*desc;
char*name;
Areas*loc;
Items*next;
Items*prev;
};

Here is the code giving me the errors:

	Items*new=createitem("NULL", "NULL", currentarea);
			name=strtok(input,",");
			new->name=name;
			desc=strtok(NULL, " ");		
			new->desc=desc;
			if (a[currentarea].items!=NULL){
                               new->next=a[currentarea].items; 
                                a[currentarea].items->prev=new; 
                                a[currentarea].items=new;}

I thought this might fix it, but no luck:

typedef struct items Items;
typedef struct areas Areas;

-Adam Rinkleff

[itCbitC]

Without a typedef use the entire struct tag, that is

struct Areas
{
    char desc[255];
    char name[255];
    struct Items*items;
    int n,s,w,e,u,d;
};

[stahta01]

Where/what is "struct node" defined as?

Tim S.

[AndrewHunter]

Some suggested reading that might answer your question: C-FAQ 1.15

[Adam Rinkleff]

Where/what is "struct node" defined as?

Tim S.

I don't know, I thought I have defined these structs. The error seems to be that it isn't properly defined. I tried what itCbitC said, but the following still gives the same errors:

typedef struct node Items;
typedef struct node Areas;

struct Areas{
char desc[255];
char name[255];
struct Items*items;
int n,s,w,e,u,d;
}; 


struct Items{
char*desc;
char*name;
struct Areas*loc;
struct Items*next;
struct Items*prev;
};




extern struct Areas a[1000];

[Adam Rinkleff]

struct Areas{
char desc[255];
char name[255];
struct Items*items;
int n,s,w,e,u,d;
}; 


struct Items{
char*desc;
char*name;
struct Areas*loc;
struct Items*next;
struct Items*prev;
};

typedef struct Items Items;
typedef struct Areas Areas;

Perhaps this is correct as per Andrew Hunter's link, at least it seems to compile.

[itCbitC]

Because the typedefs need to be fixed otherwise the highlighted line's incomplete:

typedef struct node Items;  /*  needs to be:   typedef struct Items Items  */
typedef struct node Areas;  /*  needs to be:   typedef struct Areas Areas  */

struct Areas{
char desc[255];
char name[255];
struct Items *items;   /* creates an incomplete type unless typedefs are fixed */
int n,s,w,e,u,d;
}; 


struct Items{
char*desc;
char*name;
struct Areas*loc;
struct Items*next;
struct Items*prev;
};