Question

I have a basic file I’m attempting to use.

#ifndef POINT_GUARD
#define POINT_GUARD

//------------------------------------------------------------------------------

struct Point {
    int x, y;
    Point(int xx, int yy) : x(xx), y(yy) { }
    Point() :x(0), y(0) { }
};

//------------------------------------------------------------------------------

inline bool operator==(Point a, Point b) { return a.x==b.x && a.y==b.y; } 

//------------------------------------------------------------------------------

inline bool operator!=(Point a, Point b) { return !(a==b); }

//------------------------------------------------------------------------------

#endif // POINT_GUARD

Notice that it’s wrapped in a guard. Now this is imported into two different files. I’m getting an error, though.

It complains as soon as it hits struct Point that it’s a “Redefinition of Point”. Any ideas what could be happening here?

Answer 1

I can’t reproduce the error with the input given. I placed your code in test.h, and wrote this for test.cpp:

#include "test.h"
#include "test.h"

Running g++ -Wall -c test.cpp produces no errors or warnings, and running it through the pre-processor shows that struct Point is declared only once, so the guard is working.

I’d guess there’s a declaration with the same name somewhere else, outside of the code you quoted?