INF: Using OLE to Perform Standard DDE Operations

ID Number: Q74801

3.10

WINDOWS

Summary:

In general, the Object Linking and Embedding (OLE) libraries can be

used to perform the same types of operations as the Dynamic Data

Exchange Management Library (DDEML). With the OLE libraries, an

application can:

- Initialize conversations based on application and topic names or

wild cards

- Request data for named items in negotiated formats from a server

- Establish an advise loop, (that is, request that a server notify the

client of changes to the values of specified items, and optionally

send the data when the change occurs)

- Send data from a server to a client

- Poke data from a client to a server

- Send a command (execute string) to the server

To get an idea of how these operations are performed using the OLE

libraries, review the OLE library API. Except for sending commands,

the OLE API was designed with embedded and linked objects in mind;

however, OLE is applicable to traditional, nonpersistent DDE items.

Because DDE execute strings are outside of the realm of the OLE

protocol, a special API has been provided. The OleExecute function

in OLECLI (the OLE client library) enables an application to send a

DDE execute command with an arbitrary command string. The server

responds to this command using the Execute method defined in the

OLEDOCUMENTVTBL structure.