How can I avoid the LNK2005 linker error for variables defined in a header file?

Question

I have 3 cpp files that look like this

#include \"Variables.h\"
void AppMain() {
    //Stuff...
}

They all use the same variables inside th

Answer 1

Because "int slider" is already defined in another file? Check that you have header guards...

#ifndef _VARIABLES_H_
#define _VARIABLES_H_

int slider;

#endif

If it is across multiple translation units, and you do want the variables to be different (ie not global), then maybe declare them in an anonymous namespace:

namespace {
    int slider;
}

If you do want them global, look to James' solution.