Thread: library with struct definitions

How would I define some structs in a seperate c file and have them exported?

I have inside c file stuff that looks like this:
types.c

Code:

#include "types.h"
static struct s_pos{
  ...
  };
extern struct s_cell{
  ...
  };

and in header, types.h

Code:

struct s_cell;

things are declared in this

Code:

#include "types.h"
extern struct s_cell map[256][256];

When I compile, I get error
[warning] storage size of `map` isn't known

so they must not be exported correctly.

Could someone explain or point me to a helpful page, thanks.

Include the file in which struct cell is defined.

storage size of map is unknown because any declaration with extern is not a definition. What itCbitC said was true:

Code:

/* types.h */

extern struct s_cell;

/* types.c */

struct s_cell { /* ... */ };

struct s_cell map[256][256];

This sort of thing can be useful for hiding implementations and so forth, though.

What I want to do is have the data types defined in a seperate file that will compile to an object alone and then include into another file and set up variables using those data types.

I want struct s_cell and struct s_cell map[x][y] to be in source different files.

Well as long as you compile types.c with the source that defines map, then you should be ok. Make sure to include the header in both types.c and the other source file. From what I've shown you, nothing needs to be different.

Should I be able to do something like this?

Code:

 > types.c
struct s_cell {
  int foo;
  int bar;
  };

 > types.h
struct s_cell;

 > defs.c
#include "types.h"
struct s_cell map[256][256];
map[0][0].foo = 4;
map[0][0].bar = 3;

 > defs.h
extern struct s_cell map[256][256];

 > main.c
#include "defs.h"
int main()
{map[0][0].foo = map[0][0].bar;}

Sorry, I must be misunderstanding someone.

Why not declare and define the struct in the header file?

That's not what I want to do. :P