The system broadcasts the DBT_DEVICEREMOVECOMPLETE device event when a device or piece of media has been physically removed.
To broadcast this device event, the system uses the WM_DEVICECHANGE message with wParam set to DBT_DEVICEREMOVECOMPLETE and lParam set as described following.
LRESULT CALLBACK WindowProc( HWND hwnd, // handle to window UINT uMsg, // WM_DEVICECHANGE WPARAM wParam, // device-change event LPARAM lParam // event-specific data );
A handle to a window.
The WM_DEVICECHANGE message identifier.
Set to DBT_DEVICEREMOVECOMPLETE
A pointer to a structure identifying the device removed. The structure consists of an event-independent header, followed by event-dependent members that describe the device. To use this structure, treat the structure as a DEV_BROADCAST_HDR structure, then check its dbch_devicetype member to determine the device type.
The system may broadcast a DBT_DEVICEREMOVECOMPLETE message without sending corresponding DBT_DEVICEQUERYREMOVE and DBT_DEVICEREMOVEPENDING messages. In such cases, the applications and drivers must recover from the loss of the device as best they can.
If media is being removed, the type of device arriving is a volume (the dbch_devicetype member is DBT_DEVTYP_VOLUME) and the change effects the media (the dbcv_flags member is DBTF_MEDIA).
For an example, see Detecting Media Insertion or Removal or Processing a Request to Remove a Device.
|Minimum supported client
|Minimum supported server
||Windows Server 2003