multiple file scope question

I am making a program with multiple *.c files and multiple *.h files.
I want to declare a "typedef struct" like this:

Code:

---

typedef struct node{
    char data;
    struct node* next;
)NODE;

---

Where do I have to declare it in order for it to be recognized throughout the whole program?

Do I have to make it external?
thanks.

One way is to put it in an include file that is included in every module, with something like this:

Code:

---

#ifndef NODE_DEF
#define NODE_DEF
 typedef struct node
 {
    char data;
    struct node* next;
 ) NODE;
#endif

---

Quote:

---

Do I have to make it external?

---

The extern keyword is used to tell one file that the actual declaration of that variable/struct/whatever is in another file.

For example, if you have a global variable in one .c file declared as int ImAGlobalVariable;, then you could put extern int ImAGlobalVariable; in a header file that you include in other .c files.

thanx for the replies,
i was playing around with it a little more,
whould it work if i declared the struct in one of the .h files and include it in main.c,
whould all the files recognize it that way?

It's fine to define a struct in a header file, but you want to declare instances of the struct in .c files. So you might have this:

Code:

---

// file.c

struct somestruct foo;

---

Code:

---

// file.h
#ifndef FILE_C_
#define FILE_C_

struct somestruct
{
  int a;
  int b;
};

extern struct somestruct foo;
#endif

---

And then any .c file in which you include file.h can use struct somestruct and will also have access to the foo instance of that struct.

I'd been meaning to ask this exact question(well, I thought that's how it worked, but I wanted to make sure it was okay).