Neither t_object nor t_data are used - the former isn't needed I don't think, the latter (t_data) needs to be passed somewhere it can have something put into it. I'm not sure if this was a prelude to updating MCS_read_socket. At the moment this should be:
```
MCAutoDataRef t_data;
... do read socket stuff ...
if (p_message == NULL)
{
  ctxt . GetEP() . copyasdataref(&t_data);
  ctxt . SetItToValue(*t_data);
}