I've tried searching around google for this and couldn't find anything, so I apologize if this is a repeat.

I'm have a problem returning a reference to an internal class in AngelScript.

Basically I have a class like this:

class Engine
{
public:
    AudioSystem& getAudioSystem()
    {
        return m_audioSystem;
    }
private:
    AudioSystem m_audioSystem;
};

     int r= state->RegisterObjectType("Engine", 0, asOBJ_REF | asOBJ_NOCOUNT);
     r = state->RegisterObjectMethod("Engine", "AudioSystem@ getAudioSystem()", asMETHODPR(Engine, getAudioSystem, (), AudioSystem&), asCALL_THISCALL); assert(r >= 0);

int result = state->RegisterObjectType("AudioSystem", 0, asOBJ_REF | asOBJ_NOCOUNT);
result = state->RegisterObjectMethod("AudioSystem", "bool addSound(const string &in, const string &in, const bool overwriteExisting = true, const bool useStoredPath = true, const bool isSoundEffect = false, const string extension = \".mp3\")",
		asMETHOD(AudioSystem, addSound), asCALL_THISCALL);

	result = state->RegisterObjectMethod("AudioSystem", "void playSound(const string &in, const int channel = 0, const bool loop = true, const float vol = 1.0)",
		asMETHOD(AudioSystem, playSound), asCALL_THISCALL);

void main()
{
	AudioSystem& as = engine.getAudioSystem();//.addSound("Dive into the Heart", "Dive into the Heart");
	as.addSound("Dive into the Heart", "Dive into the Heart");
	as.playSound("Dive into the Heart");
}

AudioSystem@ as = engine.getAudioSystem();

r = state->RegisterObjectMethod("Engine", "AudioSystem@ getAudioSystem()", asMETHOD(Engine, getAudioSystem), asCALL_THISCALL); assert(r >= 0);

The & cannot be used in variable declarations in AngelScript. Instead you should use the @ symbol.

I think your problem lies with how you've registered the global property 'engine'. I suspect that you're probably giving the wrong address to AngelScript, but unfortunately you didn't show us how you've declared the global instance of your Engine in your application nor how you're making the call to RegisterGlobalProperty.

Please show how you expose the global instance of your Engine to the script so we can verify if it is correct.

I'm exposing it like this:

void registerEngine(asIScriptEngine* state, Engine* engine)
{
    //class definition export code here
    registerObjectToAngelScript<Engine>(state, "engine", "Engine", *engine, true, false);
}


template <class T>
int registerObjectToAngelScript(asIScriptEngine* scriptCtx, const std::string& index, const std::string& objType, T& object, const bool byPtr = true, const bool isConst = false)
{
	std::string objDeclaration((isConst ? "const " : "") + objType + " " + (byPtr ? "@" : "") + index);
	return scriptCtx->RegisterGlobalProperty(objDeclaration.c_str(), &object);
}

my objDeclaration sctring ends up looking like this:

objDeclaration: "Engine @engine"

Hm yea when I pass a pointer only, it gives me a new/incorrectly initialized instance of Engine, so I changed the registration to

template <class T>
int registerObjectToAngelScript(asIScriptEngine* scriptCtx, const std::string& index, const std::string& objType, T& object, const bool byPtr = true, const bool isConst = false)
{
	std::string objDeclaration((isConst ? "const " : "") + objType + " " + (byPtr ? "@" : "") + index);
	T* objPtr = &object;
	return scriptCtx->RegisterGlobalProperty(objDeclaration.c_str(), &objPtr);
}

to make a pointer to a pointer. Now though, the engine instance is null (or the equivalent, 0xcccccccc in visual studio). Maybe I misunderstood what you meant?