Service Name Registration

By registering its service names with the DDEML, a server informs other DDE applications in the system that a new server is available. A server registers a service name by calling the DdeNameService function and specifying a string handle that identifies the name. In response, the DDEML sends an XTYP_REGISTER transaction to the callback function of each DDEML application in the system (except those that specified the CBF_SKIP_REGISTRATIONS filter flag in the DdeInitialize function). The XTYP_REGISTER transaction passes two string handles to a callback function: the first identifies the string specifying the base service name, and the second identifies the string specifying the instance-specific service. A client typically uses the base service name in a list of available servers, so the user can select a server from the list. The client uses the instance-specific service name to establish a conversation with a specific instance of a server application, if more than one instance is running.

A server can use DdeNameService to unregister a service name. This function causes the DDEML to send XTYP_UNREGISTER transactions to the other DDE applications in the system, informing them that they can no longer use the name to establish conversations.

A server must call DdeNameService to register its service names soon after calling DdeInitialize. A server must unregister its service names by using DdeNameService just before calling the DdeUninitialize function.