Error: incomplete type is not allowed

Question

in .h:

typedef struct token_t TOKEN;

in .c:

#include "token.h"

struct token_t
{
    char* start;
    int length;
    int type;
};

in main.c:

#include "token.h"

int main ()
{
    TOKEN* tokens; // here: ok
    TOKEN token;   // here: Error: incomplete type is not allowed
    // ...
}

The error I get in that last line:

Error: incomplete type is not allowed

What's wrong?

Answer 1

You need to move the definition of the struct into the header file:

/* token.h */

struct token_t
{
    char* start;
    int length;
    int type;
};