EvtDevicePnpStateChange function

[Applies to KMDF only]

A driver's EvtDevicePnpStateChange event callback function informs the driver that a device's Plug and Play (PnP) state machine is moving from one state to another.

Syntax

C++


EVT_WDF_DEVICE_PNP_STATE_CHANGE_NOTIFICATION EvtDevicePnpStateChange;

VOID EvtDevicePnpStateChange(
  _In_  WDFDEVICE Device,
  _In_  PCWDF_DEVICE_PNP_NOTIFICATION_DATA NotificationData
)
{ ... }

Parameters

Device [in]: A handle to a framework device object.
NotificationData [in]: A pointer to a framework-supplied WDF_DEVICE_PNP_NOTIFICATION_DATA structure that identifies the state machine's old and new states.

Return value

None

Remarks

To register an EvtDevicePnpStateChange callback function, a driver must call WdfDeviceInitRegisterPnpStateChangeCallback.

Most drivers do not need to be notified when the framework's PnP state machine changes state. For more information about the framework's PnP state machine, see State Machines in the Framework.

Examples

To define an EvtDevicePnpStateChange callback function, you must first provide a function declaration that identifies the type of callback function you’re defining. Windows provides a set of callback function types for drivers. Declaring a function using the callback function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it’s a requirement for writing drivers for the Windows operating system.

For example, to define an EvtDevicePnpStateChange callback function that is named MyDevicePnpStateChange, use the EVT_WDF_DEVICE_PNP_STATE_CHANGE_NOTIFICATION type as shown in this code example:


EVT_WDF_DEVICE_PNP_STATE_CHANGE_NOTIFICATION  MyDevicePnpStateChange;

Then, implement your callback function as follows:


_Use_decl_annotations_
VOID
 MyDevicePnpStateChange (
    WDFDEVICE  Device,
    PCWDF_DEVICE_PNP_NOTIFICATION_DATA  NotificationData
 )
  {...}

The EVT_WDF_DEVICE_PNP_STATE_CHANGE_NOTIFICATION function type is defined in the Wdfdevice.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the _Use_decl_annotations_ annotation to your function definition. The _Use_decl_annotations_ annotation ensures that the annotations that are applied to the EVT_WDF_DEVICE_PNP_STATE_CHANGE_NOTIFICATION function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for KMDF Drivers. For information about _Use_decl_annotations_, see Annotating Function Behavior.

Requirements

Minimum KMDF version	1.0
Header	Wdfdevice.h (include Wdf.h)
IRQL	PASSIVE_LEVEL