C Typedef - Incomplete Type

Question

So, out of the blue, the compiler decides to spit this in face: "field customer has incomplete type".

Here's the relevant snippets of code:

customer.c

#include <stdlib.h>
#include <string.h>

#include "customer.h"

struct CustomerStruct;
typedef struct CustomerStruct
{
    char id[8];
    char name[30];
    char surname[30];
    char address[100];
} Customer ;

/* Functions that deal with this struct here */

customer.h

A header file for customer.h

#include <stdlib.h>
#include <string.h>

#ifndef CUSTOMER_H
#define CUSTOMER_H

    typedef struct CustomerStruct Customer;

    /* Function prototypes here */

#endif

This is where my problem is:

customer_list.c

#include <stdlib.h>
#include <string.h>

#include "customer.h"
#include "customer_list.h"

#include "..\utils\utils.h"


struct CustomerNodeStruct;
typedef struct CustomerNodeStruct
{
    Customer customer; /* Error Here*/
    struct CustomerNodeStruct *next;
}CustomerNode;



struct CustomerListStruct;
typedef struct CustomerListStruct
{
    CustomerNode *first;
    CustomerNode *last;
}CustomerList;

/* Functions that deal with the CustomerList struct here */

This source file has a header file, customer_list.h ,but I don't think its relevant.

My Problem

In customer_list.c, at the line with the comment /* Error Here */, the compiler complains about field customer has incomplete type.

I've been googling this problem all day, and now im at the point of pulling out my eyeballs and blending them with strawberries.

What is the source of this error ?

Thanks in advance :)

[P.S. if I forgot to mention something, let me know. Its been a stressful day for me, as you might tell ]

Answer 1

It seems that something like

typedef struct foo bar;

won't work without the definition in the header. But something like

typedef struct foo *baz;

will work, as long as you don't need to use baz->xxx in the header.

Answer 2

Move the struct declaration to the header:

customer.h
typedef struct CustomerStruct
{
...
}