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RegisterDeviceNotification function

Registers the device or type of device for which a window will receive notifications.

Syntax


HDEVNOTIFY WINAPI RegisterDeviceNotification(
  _In_  HANDLE hRecipient,
  _In_  LPVOID NotificationFilter,
  _In_  DWORD Flags
);

Parameters

hRecipient [in]

A handle to the window or service that will receive device events for the devices specified in the NotificationFilter parameter. The same window handle can be used in multiple calls to RegisterDeviceNotification.

Services can specify either a window handle or service status handle.

NotificationFilter [in]

A pointer to a block of data that specifies the type of device for which notifications should be sent. This block always begins with the DEV_BROADCAST_HDR structure. The data following this header is dependent on the value of the dbch_devicetype member, which can be DBT_DEVTYP_DEVICEINTERFACE or DBT_DEVTYP_HANDLE. For more information, see Remarks.

Flags [in]

This parameter can be one of the following values.

ValueMeaning
DEVICE_NOTIFY_WINDOW_HANDLE
0x00000000

The hRecipient parameter is a window handle.

DEVICE_NOTIFY_SERVICE_HANDLE
0x00000001

The hRecipient parameter is a service status handle.

 

In addition, you can specify the following value.

ValueMeaning
DEVICE_NOTIFY_ALL_INTERFACE_CLASSES
0x00000004

Notifies the recipient of device interface events for all device interface classes. (The dbcc_classguid member is ignored.)

This value can be used only if the dbch_devicetype member is DBT_DEVTYP_DEVICEINTERFACE.

 

Return value

If the function succeeds, the return value is a device notification handle.

If the function fails, the return value is NULL. To get extended error information, call GetLastError.

Remarks

Applications send event notifications using the BroadcastSystemMessage function. Any application with a top-level window can receive basic notifications by processing the WM_DEVICECHANGE message. Applications can use the RegisterDeviceNotification function to register to receive device notifications.

Services can use the RegisterDeviceNotification function to register to receive device notifications. If a service specifies a window handle in the hRecipient parameter, the notifications are sent to the window procedure. If hRecipient is a service status handle, SERVICE_CONTROL_DEVICEEVENT notifications are sent to the service control handler. For more information about the service control handler, see HandlerEx.

Be sure to handle Plug and Play device events as quickly as possible. Otherwise, the system may become unresponsive. If your event handler is to perform an operation that may block execution (such as I/O), it is best to start another thread to perform the operation asynchronously.

Device notification handles returned by RegisterDeviceNotification must be closed by calling the UnregisterDeviceNotification function when they are no longer needed.

The DBT_DEVICEARRIVAL and DBT_DEVICEREMOVECOMPLETE events are automatically broadcast to all top-level windows for port devices. Therefore, it is not necessary to call RegisterDeviceNotification for ports, and the function fails if the dbch_devicetype member is DBT_DEVTYP_PORT. Volume notifications are also broadcast to top-level windows, so the function fails if dbch_devicetype is DBT_DEVTYP_VOLUME. OEM-defined devices are not used directly by the system, so the function fails if dbch_devicetype is DBT_DEVTYP_OEM.

Examples

For an example, see Registering for Device Notification.

Requirements

Minimum supported client

Windows XP

Minimum supported server

Windows Server 2003

Header

Winuser.h (include Windows.h)

Library

User32.lib

DLL

User32.dll

Unicode and ANSI names

RegisterDeviceNotificationW (Unicode) and RegisterDeviceNotificationA (ANSI)

See also

Device Management Functions
Device Notifications
BroadcastSystemMessage
HandlerEx
RegisterDeviceNotification
UnregisterDeviceNotification
DEV_BROADCAST_HDR
WM_DEVICECHANGE

 

 

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