Difference between 'data type' and variable?

I was told that when I do something like

Code:

---

#include <stdio.h>

 typedef struct{
  int fd;
  char d;
 }DIR;


 /*DIR *opendir(char *getname);*/

 int main(void) {
  return 0;
 }

---

that typedefing the struct declares a new data type. I thought a data type and variable where the same thing. Apparently they aren't. What exactly is the difference between the two then?

Chad

A type (or data type) defines the structure of data that will be stored in an object (variable) of that type.

A variable is a named instance of that data type.

In your example, DIR defines how data is stored in a variable of type DIR, but you aren't declaring any variables of that type (though you hae a commented out function prototype that returns a pointer to an object of that type.)

Okay, thanks. That makes sense.