RasDialFunc info  Overview  Group

The RasDialFunc function is an application-defined or library-defined callback function that the RasDial function calls when a change of state occurs during a RAS connection process.

VOID WINAPI RasDialFunc(

UINT unMsg,	// type of event that has occurred
RASCONNSTATE rasconnstate,	// connection state about to be entered
DWORD dwError	// error that may have occurred
);

Parameters

unMsg

Specifies the type of event that has occurred. Currently, the only event defined is WM_RASDIALEVENT.

rasconnstate

Specifies a RASCONNSTATE enumerator value that indicates the state the RasDial remote access connection process is about to enter.

dwError

Indicates the error that has occurred, or zero if no error has occurred.

RasDial calls RasDialFunc with dwError set to zero upon entry to each connection state. If an error occurs within a state, RasDialFunc is called again with a nonzero dwError value.

Return Values

None.

Remarks

A RasDial connection operation is suspended during a call to a RasDialFunc callback function. For that reason, your RasDialFunc implementation should generally return as quickly as possible. There are two exceptions to that rule. Asynchronous (slow) devices such as modems often have time-out periods measured in seconds rather than milliseconds; a less-than-prompt return from a RasDialFunc function is generally not a problem. The prompt return requirement also does not apply when dwError is nonzero, indicating that an error has occurred. It is safe, for example, to put up an error dialog box and wait for user input.

Your RasDialFunc implementation should not depend on the order or occurrence of particular RASCONNSTATE connection states, because this may vary between platforms.

Do not call the RasDial function from within a RasDialFunc callback function. You can call the RasGetConnectStatus, RasEnumEntries, RasEnumConnections, RasGetErrorString, and RasHangUp functions from within the callback function. For example, calling RasGetConnectStatus from within a callback function would be useful for determining the name and type of the connecting device.

Note that, for convenience, RasHangUp can be called from within a RasDialFunc callback function. However, much of the hang-up processing occurs after the RasDialFunc callback function has returned.

RasDialFunc is a placeholder for the application-defined or library-defined function name.

See Also

RASCONNSTATE, RasDial, RasDialFunc1, RasDialFunc2, RasEnumConnections, RasEnumEntries, RasGetConnectStatus, RasGetErrorString, RasHangUp