DDEML - DDEML API interface unit


4.17. D3Dx8 - Headers of helper library for 3D programming	Table of Contents	4.19. DDraw - DirectDraw interface unit

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4. Standard Units

4.18. DDEML - DDEML API interface unit

Targets: Win32 only

This module contains the Dynamic Data Exchange Management Library interface.

In Microsoft Windows, Dynamic Data Exchange (DDE) is a form of interprocess communications that uses shared memory to exchange data between applications. Applications can use DDE for one-time data transfers and for ongoing exchanges and updating of data.

DDE differs from the clipboard data-transfer mechanism that is also part of the Windows operating system. One difference is that the clipboard is almost always used as a one-time response to a specific action by the user ? such as choosing the Paste command from a menu. Although DDE may also be initiated by a user, it typically continues without the user's further involvement.

The Dynamic Data Exchange Management Library (DDEML) provides an application programming interface (API) that simplifies the task of adding DDE capability to a Windows application. Instead of sending, posting, and processing DDE messages directly, an application uses the functions provided by the DDEML to manage DDE conversations. A DDE conversation is the interaction between client and server applications. The DDEML also provides a means for managing the strings and data shared among DDE applications. Instead of using atoms and pointers to shared memory objects, DDE applications create and exchange string handles, which identify strings, and data handles, which identify DDE objects. The DDEML provides a function (DdeNameService) that enables a server application to register the service names it supports. The service names are then broadcast to other applications in the system, which use the names to connect to the server. The DDEML also ensures compatibility among DDE applications by requiring them to implement the DDE protocol in a consistent manner.

Existing applications using the message-based DDE protocol are fully compatible with those that use the DDEML; that is, an application using message-based DDE can establish conversations and perform transactions with applications using the DDEML. Instead of using DDE messages in your new application, take advantage of the DDEML and the many improvements it offers.

To use the API elements of the DDEML, you must USE DDEML.PAS unit in your source files.

For more info look the "Dynamic Data Exchange Reference" in WIN32.HLP.


4.17. D3Dx8 - Headers of helper library for 3D programming	Table of Contents	4.19. DDraw - DirectDraw interface unit

- 4.18. -