DDE¶
DDE, or Dynamic Data Exchange, is a form of communication between two processes. The two processes involved are known as the client and the server. Programs that support DDE can be DDE clients, DDE servers or both. Sculptor supports both DDE client functions and a DDE server interface.
The general concept of DDE is that a conversation is set up between a client and a server. Several different conversations can exist at the same time, and a single server can support multiple client connections simultaneously. The server program can supply information to the client and can, in some cases, be sent commands by the client. Windows programs such as Program Manager and Microsoft Word are DDE servers. DDE enables a Sculptor program to send commands to Program Manager to open and add program groups. In order to use the facilities provided by any particular DDE server, it is necessary to consult the program’s DDE documentation.
Each conversation is identified by a service name and a topic name.
The service name is usually the name of the server program. For example, Windows Program Manager provides the service “PROGMAN”.
A single server may support several conversation topics, and so the topic name is used to specify the topic required. Program Manager only supports a single topic, also called “PROGMAN”. The topic must be specified even if only one is supported. Most services support the topic “SYSTEM”.
Once a conversation has been established, data can be requested by the use of item names. The item name “GROUPS”, for example, asks Program Manager to send a list of all program groups.