Question

I’m having a problem with forward declarations in a nested namespace. I put a forward declaration for a class or struct in a nested namespace and when I try to use it in the parent of that namespace I get an error. I don’t know what to do.

This is what the code looks like:

#include "Data\Types.hpp"

namespace GameEngine
{
    class Console
    {
    public:
        class Renderer : public RenderComponent2D
        {
        public:
            Renderer(Console*, const GameEngine::DataProcessing::FontData*);
//...

and in Data\Types.hpp:

namespace GameEngine
{
    namespace DataProcessing
    {
        struct FontData;
//...

and the error MinGW gives me is :

'FontData' in namespace 'GameEngine::DataProcessing' does not name a type

I appreciate any help or suggestions with this problem.

Answer 1

May be problem in declaration of method. You are already inside GameEngine namespace:

namespace GameEngine
{
    class Console

But in declaration you use this namespace too :

 Renderer(Console*, const GameEngine::DataProcessing::FontData*);

Try it without GameEngine :

 Renderer(Console*, const DataProcessing::FontData*);