OLE is implemented through the use of two DLLs: OLESVR.DLL and OLECLI.DLL. A third DLL, named SHELL.DLL, is used at certain times by the applications and the setup program to maintain and query the registration database; for more information on this DLL, see Chapter 10, "Using the Registration Database."
OLESVR.DLL contains functions that are called by the server application during OLE operations. Figure 37 shows that OLESVR.DLL makes callbacks to the server application to perform operations on objects and documents, and to invoke the server functions such as open a file, edit a file, and so on.
Figure 37. Relationship between applications and OLE DLLs
Note All communication between the OLESVR.DLL and OLECLI.DLL is handled via DDE, which is transparent to the client and server applications.