// Client & Server Header struct WorldState{ vector<Client> vClients; // Other world info here}; class IMessageHandler{public: virtual void Release() = 0; virtual bool HandleMessage(int nMsg, void* pMsgData) = 0;}; IMessageHandler* Create(WorldState* pState);typedef IMessageHandler* (*pfnCreate)(WorldState* pState); // DLL Headerclass CMessageHandler : public IMessageHandler{public: CMessageHandler(WorldState* pState) :m_pState(pState) {} virtual void Release() {delete this;} virtual bool HandleMessage(int nMsg, void* pMsgData); protected: WorldState* m_pState; // Usual member variables etc here}; // DLL SourceIMessageHandler* Create(WorldState* pState){ return new CMessageHandler(pState);} bool CMessageHandler::HandleMessage(int nMsg, void* pMsgData){User* pUser; switch(nMsg) { case 1000: pUser = (SUser*)pMsgData; m_pState->listOfUsers.Remove(pUser->ID); return true; default: return false; }} // In the servers init code (server has variable m_pHandler)// IMessageHandler* m_pHandler; HMODULE hMod = LoadLibrary("Messages.dll");pfnCreate func = (pfnCreate)GetProcAddress("Create");m_pHandler = func(m_pState); // When server recieves a message:m_pHandler->HandleHessage(int nMsg, void* pData); I haven''t tested that code at all, its just as an example. So you pass the message handler a state block, which should have information about all the users in it along with other information. If you use e.g. a vector, you''ll have to be careful not to allocate memory in the DLL and free it in the EXE (or vice-versa).
When you recieve a message, you pass it along to your message handler in your DLL. Maybe abstract classes is overkill, you could just as well go and have a function, and a global for the world state.
HTH
