WM_DEVICECHANGE Overview  Group

The WM_DEVICECHANGE device message notifies an application or device driver of a change to the hardware configuration of a device or the computer.

Event = (UINT) wParam;
dwData = (DWORD) lParam;
 

Parameters

Event

Event type. This parameter can be one of the following values:

Value	Meaning
DBT_CONFIGCHANGECANCELED	A request to change the current configuration (dock or undock) has been canceled.
DBT_CONFIGCHANGED	The current configuration has changed, due to a dock or undock.
DBT_DEVICEARRIVAL	A device has been inserted and is now available.
DBT_DEVICEQUERYREMOVE	Permission is requested to remove a device. Any application can deny this request and cancel the removal.
DBT_DEVICEQUERYREMOVEFAILED	A request to remove a device has been canceled.
DBT_DEVICEREMOVECOMPLETE	A device has been removed.
DBT_DEVICEREMOVEPENDING	A device is about to be removed. Cannot be denied.
DBT_DEVICETYPESPECIFIC	A device-specific event has occurred.
DBT_QUERYCHANGECONFIG	Permission is requested to change the current configuration (dock or undock).
DBT_USERDEFINED	The meaning of this message is user-defined.

dwData

Address of a structure that contains event-specific data. Its meaning depends on the given event.

Return Values

Return TRUE to grant a requested action.

Return BROADCAST_QUERY_DENY to deny a requested action.

Remarks

For devices that offer software-controllable features, such as ejection and locking, the operating system typically sends a DBT_DEVICEREMOVEPENDING message to let applications and device drivers end their use of the device gracefully.

If the operating system forcibly removes a device, it may not send a DBT_DEVICEQUERYREMOVE message before doing so.

DBT_CONFIGCHANGECANCELED, DBT_CONFIGCHANGED, DBT_DEVICEARRIVAL, DBT_DEVICEQUERYREMOVE, DBT_DEVICEQUERYREMOVEFAILED, DBT_DEVICEREMOVECOMPLETE, DBT_DEVICEREMOVEPENDING, DBT_DEVICETYPESPECIFIC, DBT_QUERYCHANGECONFIG, DBT_USERDEFINED