Linked List error [SOLVED]

Lexion · 2009-09-12 20:32:44

I have written linked lists many times, but I'm stumped by this error.

header

#include <stdio.h>

typedef struct
{
char *str;
struct strstack *next;
} strstack;

void connect(struct strstack *a, struct strstack *b);

source

#include <stdio.h>
#include "strstack.h"

void connect(struct strstack *a, struct strstack *b)
{
a->next = b;
}

errors

gcc -g -O2 --std=c99 -c strstack.c
strstack.c: In function 'connect':
strstack.c:7: error: dereferencing pointer to incomplete type
make: *** [strstack] Error 1

Does anybody have any idea what causes this?

Last edited by Lexion (2009-09-12 23:48:49)

gnud · 2009-09-12 21:08:21

Yes.

Your typedef is silly.

Replace with

typedef struct stack_s
{
char *str;
struct stack_s *next;
} stack_t;

or similar.

You have to name the struct, and use the struct name when declaring the next pointer. You can typedef it too, if you want to, but that name can't be used in the struct declaration.

gnud · 2009-09-12 21:09:24

To clarify: You don't declare "struct strstack" anywhere. You declare an unnamed struct, and typedef that struct as strstack.

ewaller · 2009-09-12 21:22:41

There is an article on this at http://www.netalive.org/codersguild/posts/1753.shtml

Try:

struct strstack
{
char *str;
struct strstack *next;
} ;

Lexion · 2009-09-12 23:48:08

Thanks all, it works great!

Arch Linux

#1 2009-09-12 20:32:44

Linked List error [SOLVED]

#2 2009-09-12 21:08:21

Re: Linked List error [SOLVED]

#3 2009-09-12 21:09:24

Re: Linked List error [SOLVED]

#4 2009-09-12 21:22:41

Re: Linked List error [SOLVED]

#5 2009-09-12 23:48:08

Re: Linked List error [SOLVED]

Board footer