Variable already defined in .obj; What is going on here?

Question

head.h

#pragma once

namespace foo
{
    int bar;

    int funct1();
}

head.cpp

#include \"head.h\"

int foo::funct1()
{
         


        

Answer 1

I am not redefining anything. I am literally just assigning 1 to the variable

You're redefining the variable!

head.cpp has one via #include "head.h", and main.cpp has one via #include "head.h".

You need to merely declare it (unusual but not too strange) in the header:

extern int bar;

…then define it in one translation unit. This is just like what you do with static class members (albeit with slightly different syntax).

Since C++17, you may do this by instead plopping the inline keyword on to your definition.

Alternatively, avoid mutable globals…