About Dynamic Data Exchange

DDE is a form of inter-process Windows communication that uses shared memory to exchange data between applications. Applications can use DDE DDE was originally called Dynamic Data Linking, or DDL. It is aMicrosoft Windows 3 hotlink protocol that allows application programs to communicate using a client-server model. Whenever the server (or "publisher") modifies part of a document which is being shared via DDE, one or more clients ("subscribers") are informed and include the modification in the copy of the data on which they are working. for one-time data transfers, for ongoing exchanges, and for updating of data.  A typical DDE conversation works as follows.

Register the application as DDE client

Open DDE connection (note that QWS3270 Secure requires a pre-existing session)

Initiate DDE transaction(s)

Close DDE connection(s)

Unregister the application

DDE always occurs between a client application (your application) and a server application (QWS3270 Secure). The DDE client application initiates the exchange by establishing a conversation with the server to send transactions to the server. A transaction is a request for data or services. The DDE server application responds to transactions by providing data or services to the client.