Bearbeta ett asynkront drivrutinsmeddelande

När operativsystemet anropar en registrerad återanropsfunktion skickar den en pekare till en DEVICE_INTERFACE_CHANGE_NOTIFICATION struktur i parametern NotificationStructure .

I följande kodexempel visas en implementering av en återanropsfunktion som bearbetar asynkrona drivrutinsmeddelanden för processorer:

// Asynchronous processor notification callback function
NTSTATUS
  AsyncProcessorCallback(
    IN PVOID NotificationStructure,
    IN PVOID Context
    )
{
  PDEVICE_INTERFACE_CHANGE_NOTIFICATION Notification;
  ULONG ProcessorCount;
  KAFFINITY ActiveProcessors;

  Notification = 
    (PDEVICE_INTERFACE_CHANGE_NOTIFICATION)
      NotificationStructure;

  // Verify that this notification is about a processor
  // that is being added to the hardware partition.
  if (IsEqualGUID(
        &Notification->Event,
        &GUID_DEVICE_INTERFACE_ARRIVAL
        ))
  {
    // Get the current processor count and affinity
    ProcessorCount =
      KeQueryActiveProcessorCount(
        &ActiveProcessors
        );

    // Adjust any resource allocations that are based
    // on the number of processors.
    ...

    // Adjust the assignment of resources that are
    // assigned to specific processors.
    ...

    // Begin scheduling any per processor threads
    // on the new processor.
    ...

    // Adjust the scheduling of DPCs and other threads
    ...

    // Adjust any load balancing algorithms
    ...
  }

  // Always return success status
 return STATUS_SUCCESS;
}

I följande kodexempel visas en implementering av en återanropsfunktion som bearbetar asynkrona drivrutinsmeddelanden för minne:

// Asynchronous memory notification callback function
NTSTATUS
  AsyncMemoryCallback(
    IN PVOID NotificationStructure,
    IN PVOID Context
    )
{
  PDEVICE_INTERFACE_CHANGE_NOTIFICATION Notification;

  Notification = 
    (PDEVICE_INTERFACE_CHANGE_NOTIFICATION)
      NotificationStructure;

  // Verify that this notification is about memory
  // that is being added to the hardware partition.
  if (IsEqualGUID(
        &Notification->Event,
        &GUID_DEVICE_INTERFACE_ARRIVAL
        ))
  {
    // Increase the size of any memory buffers
    // for optimal performance of the driver.
    ...
  }

  // Always return success status
  return STATUS_SUCCESS;
}