一本在讲述USB驱动程式的书 及其范例原码

				// Control.cpp -- IOCTL handlers for notify driver
				// Copyright (C) 1999, 2000 by Walter Oney
				// All rights reserved
				
				#include "stddcls.h"
				#include "driver.h"
				#include "ioctls.h"
				
				///////////////////////////////////////////////////////////////////////////////
				
				#pragma PAGEDCODE
				
				NTSTATUS DispatchControl(PDEVICE_OBJECT fdo, PIRP Irp)
					{							// DispatchControl
					PDEVICE_EXTENSION pdx = (PDEVICE_EXTENSION) fdo->DeviceExtension;
				
					NTSTATUS status = STATUS_SUCCESS;
					ULONG info = 0;
				
					PIO_STACK_LOCATION stack = IoGetCurrentIrpStackLocation(Irp);
					ULONG cbin = stack->Parameters.DeviceIoControl.InputBufferLength;
					ULONG cbout = stack->Parameters.DeviceIoControl.OutputBufferLength;
					ULONG code = stack->Parameters.DeviceIoControl.IoControlCode;
				
					switch (code)
						{						// process request
				
					case IOCTL_WAIT_NOTIFY:				// code == 0x800
						{						// IOCTL_WAIT_NOTIFY
						if (cbout < sizeof(ULONG))
							status = STATUS_INVALID_PARAMETER;
						else
							status = GenericCacheControlRequest(pdx->pgx, Irp, &pdx->NotifyIrp);
						break;
						}						// IOCTL_WAIT_NOTIFY
				
					case IOCTL_GENERATE_EVENT:				// code == 0x801
						{						// IOCTL_GENERATE_EVENT
						if (cbin < sizeof(ULONG))
							{					// buffer too small
							status = STATUS_INVALID_PARAMETER;
							break;
							}					// buffer too small
				
						PIRP nfyirp = GenericUncacheControlRequest(pdx->pgx, &pdx->NotifyIrp);
						if (nfyirp)
							{					// complete notification IRP
							*(PULONG) nfyirp->AssociatedIrp.SystemBuffer = *(PULONG) Irp->AssociatedIrp.SystemBuffer;
							CompleteRequest(nfyirp, STATUS_SUCCESS, sizeof(ULONG));
							}					// complete notification IRP
						else
							status = STATUS_UNSUCCESSFUL;
				
						break;
						}						// IOCTL_GENERATE_EVENT
				
					default:
						status = STATUS_INVALID_DEVICE_REQUEST;
						break;
				
						}						// process request
				
					return status == STATUS_PENDING ? status : CompleteRequest(Irp, status, info);
					}							// DispatchControl
				
				#pragma LOCKEDCODE				// force inline functions into nonpaged code