I'm trying to force function caller from a specific class. For example this code bellow demonstrate my problem. I want to make 'use' function would be called only from class A. I'm using a global namespace all over the project.

a.h

#include "b.h"
namespace GLOBAL{

class A{
public:
    void doSomething(B);
}
}

a.cpp

#include "a.h"
using namespace GLOBAL;

void A::doSomething(B b){

    b.use();
}

b.h

namespace GLOBAL{

class B{
public:
    friend void GLOBAL::A::doSomething(B);
private:
    void use();
}

Compiler says:

‘GLOBAL::A’ has not been declared

‘void GLOBAL::B::use()’ is private

Can anyone help here ?

Thanks a lot,

Mike.