AutoDial Connection Operations

When an attempt to connect to a network address fails because the host cannot be reached, the system searches the AutoDial mapping database for the address. If the address is in the database, the system initiates an AutoDial operation for the RASAUTODIALENTRY, if any, that corresponds to the local TAPI dialing location.

The Win32 API provides functions that enable you to set and query AutoDial parameters that control AutoDial connections. You can call the RasSetAutodialEnable function to enable or disable the AutoDial feature for a specified TAPI dialing location. The RasGetAutodialEnable function indicates whether the AutoDial feature is enabled for a specified TAPI dialing location. For more information about TAPI dialing locations, see the TAPI documentation. You can call the RasSetAutodialParam function to set other AutoDial connection parameters. For example, you can disable AutoDial connections for the current logon session. Call the RasGetAutodialParam function to determine the current value of the AutoDial connection parameters.

The system provides a default user interface for AutoDial dialing operations. However, you can create an AutoDial dynamic-link library (DLL) to provide a custom user interface for AutoDial dialing operations involving specified phone-book entries. Your AutoDial DLL must export both an ANSI and a Unicode version of a RASADFunc AutoDial handler.

To enable your custom AutoDial handler for a phone-book entry, call the RasSetEntryProperties function to set the properties for that entry. The szAutodialDll and szAutodialFunc members of the RASENTRY structure passed to RasSetEntryProperties specify the name of your AutoDial DLL and the name of your RASADFunc function, excluding the "A" or "W" suffix.

When the system starts an AutoDial operation for a phone-book entry with a custom AutoDial handler, it calls the specified RASADFunc. The RASADFunc function receives a pointer to a RASADPARAMS structure that indicates the location and parent window for the window of your user interface. Your RASADFunc can start a thread to perform the custom dialing operation. The RASADFunc function returns TRUE to indicate that it took over the dialing, or FALSE to allow the system to perform the dialing. Your custom dialing operation must use the RasDial function to do the actual dialing. When the dialing operation has been completed, the custom dialing operation indicates success or failure by setting the variable pointed to by the lpdwRetCode parameter passed to RASADFunc.