Thread: Header Files Typedef Redefintion

Hello,

I have 3 c files and 2 header files:
main.c, lifecycle.c, table.c, lifecycle.h and table.h
I worked on the table in a different problem with a different main and it works fine.

The issue I am having is that in both lifecycle.h and table.h I have

Code:

typedef enum BOOL { false, true } Boolean;

So I get errors like: "error: redefinition of enumerator 'false'" or "note: previous definition is here"

The way I have linked this is lifecycle.c include:

Code:

#include "lifecycle.h"
#include "table.h"

table.c includes only it's corresponding header file table.h.
main.c includes only lifecycle.h

I get that I should only have this typdef in 1 place because this duplication is causing error, but I'm not sure the best place to put this.
I am not used to using this many files.

So to clarify I want this typedef to work with table.c and lifecycle.c and main.c (all my c files).
I tried moving this typedef but the 2 header files have Boolean returns so the headers must also have access to this typedef.

Thanks,

Do your header files have the proper inclusion guards?

Please post the contents of the headers, or better yet a small complete program that illustrates the problem.

Jim

By guards do you mean this?:

Code:

#ifndef _TABLE_H
#define _TABLE_H

Code:

#ifndef _LIFECYCLE_H
#define _LIFECYCLE_H

At the end of each header file is the corresponding #endif.
The functions in both header files have returns of Boolean as mentioned in the original post.

Originally Posted by jimblumberg

Do your header files have the proper inclusion guards?

Please post the contents of the headers, or better yet a small complete program that illustrates the problem.

Jim

If your compiler defaults to the C99 C Standard (or higher) or you are using a compiler flag to force C99 or higher, then just:

Code:

#include <stdbool.h>

and use "bool", "true" and "false" as defined in this header file and the C99+ Standards.

Then instead of doing the typedef in several include files only use the definition in the lifecycle.h file. Include that file in any file that requires that typedef.

Also note that _LIFECYCLE_H is a bad practice because any identifier starting with an underscore and an upper case letter or another underscore are reserved.

Jim

*edit: realized I didn't need to include it in both table.c and table.h only table.h because table.c includes the table.h.

Actually IMO you should include it in both table.c and table.h if both of these files require the typedef. Never rely on some other file including a required header.


Jim

ok, will do, thanks for the advice.

Out of curiosity, Which compiler & version are you using, and what C Standard does your compiler default to, and are you overriding that default with a lower or higher level?

Possible levels are:

C89/90
C99
C11

Thanks!