Dereferencing Pointer to incomplete type Linked List - C

Question

I've been trying to figure this out for a while now, but cannot find a solution. I am building a linked list and when I try to pass the list as a pointer to anything I get an error: Dereferencing Pointer to incomplete type.

Here is my struct declaration

typedef struct listStruct{
 char *name;
 int size;
 boolean inRestStatus;
 list *next;
 }list;

and one of the many functions that do not work.

void addToList(list *l, char * name, int size){
list *tmp;
while(l->next != NULL){
        l = l->next;
        }
tmp = malloc(sizeof(list));
tmp->name = name;
tmp->size = size;
tmp->inRestStatus = NO;
tmp->next = NULL;
l->next = tmp;
}

and the header

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

typedef struct listStruct list;

I have tried changing the struct declaration to

typedef struct listStruct list{
...
};

and received the error: request for member in something not structure or union. If anyone has any ideas that'd be awesome.

Edit

The struct definition is/was in a main function in a seperate file than the function, I have since moved the definition to the header file.

Describe your file structure fully: what file contains what piece of code. — AnT

Vlad from Moscow Vlad from Moscow · Accepted Answer · 2015-02-25T20:54:06

It seems that you declared only typedef name in the header

typedef struct listStruct list;

Thus the module where function

void addToList(list *l, char * name, int size);

is defined does not know the definition of the structure.

You have to include the structure definition in the header as for example

typedef struct listStruct{
 char *name;
 int size;
 boolean inRestStatus;
 struct listStruct *next;
 }list;

that it would be accessible in the module where the function is defined.

Take into account that this method

void addToList(list *l, char * name, int size){
list *tmp;
while(l->next != NULL){
        l = l->next;
        }
tmp = malloc(sizeof(list));
tmp->name = name;
tmp->size = size;
tmp->inRestStatus = NO;
tmp->next = NULL;
l->next = tmp;
}

is also wrong. For example l can be equal to NULL can't it?

Also simple copying pointers

tmp->name = name;

looks questionably. Should you allocate memory to store a copy of a string pointed to by argument name?

Dereferencing Pointer to incomplete type Linked List - C

2 Answers