Release 10.1A: OpenEdge Development:
Programming Interfaces

Windows Dynamic Data Exchange

Dynamic data exchange (DDE) is a general protocol for inter-process communication in Windows. This protocol allows any two Windows applications to communicate as client and server, where the client initiates communications with the server and the server provides data and services to the client.

Progress supports DDE communications acting as a DDE client only. Using 4GL DDE statements, your OpenEdge application can initiate and maintain communications with any other Windows application with DDE server capability. This communications includes exchanging data with the server and directing the server to execute server-defined commands. Your OpenEdge application can communicate with different server applications during a session, and can even access entirely new server applications without modifying your existing Progress code.

The following sections describe how to use DDE in your OpenEdge applications. For more information on DDE concepts and facilities, see the Windows programming documentation on DDE.

This chapter contains the following sections:

Using the Dynamic Data Exchange protocol
Structuring a DDE conversation in Progress
Defining conversation endpoints—DDE frames
Opening DDE conversations
Exchanging data in conversations
Closing DDE conversations
DDE example