This module contains the Dynamic Data Exchange Management Library
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.