The client application uses the following data structures, the prototypes of which are defined in OLE.H:
| Structure | Contents, as defined in OLE.H |
| OLESTREAM | A single pointer (LPOLESTREAMVTBL) to the OLESTREAMVTBL structure that provides stream input and output functions. |
| OLESTREAMTVTBL | Far pointers to functions OLECLI.DLL uses for stream operations on objects. |
| OLECLIENT | A single pointer (LPOLECLIENTVTBL) to the client callback VTBL, OLECLIENTVTBL. |
| OLECLIENTVTBL | Far pointer to the client CallBack function. |