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Windows NT
Import Library
Header File
Platform Notes


The RasDial function establishes a RAS connection between a RAS client and a RAS server. The connection data includes callback and user authentication information.

DWORD RasDial(

// pointer to function extensions data
LPTSTR lpszPhonebook,
// pointer to full path and filename of phone-book file
// pointer to calling parameters data
DWORD dwNotifierType,
// specifies type of RasDial event handler
LPVOID lpvNotifier,
// specifies a handler for RasDial events
// pointer to variable to receive connection handle



Windows NT:

Points to a RASDIALEXTENSIONS structure that specifies a set of RasDial extended features to enable. If you do not need to enable any of the extensions, set this parameter to NULL.

Windows 95:

This parameter is ignored. On Windows 95, RasDial always uses the default behaviors for the RASDIALEXTENSIONS options.


Windows NT: Pointer to a null-terminated string that specifies the full path and filename of a phone-book (.PBK) file. If this parameter is NULL, the function uses the current default phone-book file. The default phone-book file is the one selected by the user in the User Preferences property sheet of the Dial-Up Networking dialog box.

Windows 95: This parameter is ignored. Dial-up networking stores phone-book entries in the registry rather than in a phone-book file.


Points to a RASDIALPARAMS structure that specifies calling parameters for the RAS connection.

The caller must set the RASDIALPARAMS structure's dwSize member to the sizeof(RASDIALPARAMS) to identify the version of the structure being passed.


Specifies the nature of the lpvNotifier parameter. If lpvNotifier is NULL, dwNotifierType is ignored. If lpvNotifier is not NULL, set dwNotifierType to one of the following values:

The lpvNotifier parameter is a handle to a window to receive progress notification messages. In a progress notification message, wParam is the equivalent of the rasconnstate parameter of RasDialFunc and RasDialFunc1, and lParam is the equivalent of the dwError parameter of RasDialFunc and RasDialFunc1.
The progress notification message uses a system registered message code. You can obtain the value of this message code as follows:
{UINT unMsg =
RegisterWindowMessageA( RASDIALEVENT );
if (unMsg == 0)

The lpvNotifier parameter points to a RasDialFunc callback function.

The lpvNotifier parameter points to a RasDialFunc1 callback function.

Windows NT: The lpvNotifier parameter points to a RasDialFunc2 callback function.


Specifies a window handle or a RasDialFunc, RasDialFunc1, or RasDialFunc2 callback function to receive RasDial event notifications. The dwNotifierType parameter specifies the nature of lpvNotifier. Please refer to its description preceding for further detail.

If this parameter is not NULL, RasDial sends the window a message, or calls the callback function, for each RasDial event. Additionally, the RasDial call operates asynchronously: RasDial returns immediately, before the connection is established, and communicates its progress via the window or callback function.

If lpvNotifier is NULL, the RasDial call operates synchronously: RasDial does not return until the connection attempt has completed successfully or failed.

If lpvNotifier is not NULL, notifications to the window or callback function can occur at any time after the initial call to RasDial. Notifications end when one of the following events occurs:

  • The connection is established. In other words, the RAS connection state is RASCS_Connected.

  • The connection fails. In other words, dwError is nonzero.

  • RasHangUp is called on the connection.

The callback notifications are made in the context of a thread captured during the initial call to RasDial.


Points to a variable of type HRASCONN. You must set the HRASCONN variable to NULL before calling RasDial. If RasDial succeeds, it stores a handle to the RAS connection into *lphRasConn.

Return Values

If the function succeeds, the immediate return value is zero. In addition, the function stores a handle to the RAS connection into the variable pointed to by lphRasConn.

If the function fails, the immediate return value is a nonzero error value, either from the set listed in the RAS header file or ERROR_NOT_ENOUGH_MEMORY.


Errors that occur after the immediate return can be detected by RasGetConnectStatus. Data is available until an application calls RasHangUp to hang up the connection.

An application must eventually call RasHangUp whenever a non-NULL connection handle is stored into *lphRasConn. This applies even if RasDial returns a nonzero (error) value.

An application can safely call RasHangUp from a RasDial notifier callback function. If this is done, however, the hangup does not occur until the routine returns.

Windows NT:

If the structure pointed to by lpRasDialExtensions enables RDEOPT_PausedStates, the RasDial function pauses whenever it enters a state in which the RASCS_PAUSED bit is set to one. To restart RasDial from such a paused state, call RasDial again, passing the connection handle returned from the original RasDial call in *lphRasConn. The same notifier used in the original RasDial call must be used when restarting from a paused state.

To specify that RasDial should enter a RASCS_CallbackSetByCaller state, set lpRasDialParams->szCallbackNumber to "*" on the initial call to RasDial. When your notification handler is called with this state, you can set the the callback number to a number supplied by the user.

Windows 95:

Windows 95 does not support the RASCS_CallbackSetByCaller state or any of the other paused states.

See Also

, RasDialFunc, RasDialFunc1, RasDialFunc2, RasGetConnectStatus, RasHangUp, RASDIALEXTENSIONS, RASDIALPARAMS, WM_RASDIALEVENT

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