struct tMessage
{
    int    iFromUser;
    int    iFlags;
    string szMessage;
};

class CClient
{
public:
     Execute();
     vector<tMessage> *pMsgQueue;
};

class CServer
{
public:
    CServer() {}
    ~CServer() {}
    Startup(...);
    ....
private:
    ClientData
    vector<tMessage> MessageQueue;
};
  

  
CServer::Startup(...)
{
    ClientData = new CClient[iMaxConn];
    for (int i = 0; i < iMaxConn; i++)
        ClientData[i].pMsgQueue = &MessageQueue
}
  

  
CClient::Execute()
{
    //other shutdown code

    pMsgQueue->push_back(Msg); // Push in msg queue

    return (0);
}