Friend classes across different namespaces. Is that possible

Question

I\'m having problems trying to use the friend feature of C++. I have these interfaces:

#pragma once
#include \"Mesh3D.h\"
#include 
namespace t         


        

Answer 1

See if something like this works a bit better (for the moment, I've merged them into a single source file).

#include <string>

namespace tools {
    namespace sysInput {
        class CGeometryManager3D;
    }
}

namespace render {   
    class CMesh3D
    {
    public:
        friend class tools::sysInput::CGeometryManager3D;
        CMesh3D(void);
        ~CMesh3D(void);
    };    
}

namespace tools {
    namespace sysInput{
        class CGeometryManager3D
        {
        public:
            bool loadFromFile(render::CMesh3D& mesh, std::string filename);
            CGeometryManager3D(void);
            ~CGeometryManager3D(void);
        };

    };    
}

Answer 2

I guess you need to remove following code in the second file:

#include "GeometryManager.h"

class CGeometryManager3D;

The first line causes circular inclusion as the comments in the question suggests;

The second line declares a totally irrelevant class as it is in the global name space;