c# - WinUSB_Initialize 函数出现 INVALID_FUNCTION (0x1) 错误

Question

为什么WinUSB_Initialize函数会出现INVALID_FUNCTION (0x1) Error？这是 winusb.dll 中的一个函数，它返回一个接口(interface)句柄。

我想获得一个接口(interface)句柄。我已经有一个设备句柄。

internal struct devInfo
        {
            internal SafeFileHandle deviceHandle;
            internal IntPtr winUsbHandle;
            internal Byte bulkInPipe;
            internal Byte bulkOutPipe;
            internal Byte interruptInPipe;
            internal Byte interruptOutPipe;
            internal UInt32 devicespeed;
        }

    internal const Int32 FILE_ATTRIBUTE_NORMAL = 0X80;
        internal const Int32 FILE_FLAG_OVERLAPPED = 0X40000000;
        internal const Int32 FILE_SHARE_READ = 1;
        internal const Int32 FILE_SHARE_WRITE = 2;
        internal const UInt32 GENERIC_READ = 0X80000000;
        internal const UInt32 GENERIC_WRITE = 0X40000000;
        internal const Int32 OPEN_EXISTING = 3;

        [DllImport("winusb.dll", SetLastError = true)]
        internal static extern Boolean WinUsb_Initialize
        (SafeFileHandle DeviceHandle,
        ref IntPtr InterfaceHandle);

        internal devInfo myDevInfo; // = new devInfo();

        public IntPtr Get_WinUSB_handle()
        {

            Guid myGuid = Get_HID_GUID();
            IntPtr deviceInfoSet = Get_Device_Info_Set(myGuid);
            SP_DEVICE_INTERFACE_DATA MyDeviceInterfaeData = Get_Device_Interface_Data(deviceInfoSet, myGuid);
            IntPtr detailDataBuffer = Get_Structure_with_Device_PathName(deviceInfoSet, ref MyDeviceInterfaeData);
            string devicePathName = Get_Device_PathName(detailDataBuffer);

           myDevInfo.deviceHandle= CreateFile(devicePathName,
           (GENERIC_WRITE | GENERIC_READ),
           FILE_SHARE_READ | FILE_SHARE_WRITE,
           IntPtr.Zero,
           OPEN_EXISTING,
           FILE_FLAG_OVERLAPPED,
           0);

               Boolean success;
               success = WinUsb_Initialize(myDevInfo.deviceHandle, ref myDevInfo.winUsbHandle);
               System.Console.WriteLine(Marshal.GetLastWin32Error());
               System.Console.WriteLine(success);


            return myDevInfo.winUsbHandle;

        }

Answer 1

       success = WinUsb_Initialize(...);
       System.Console.WriteLine(Marshal.GetLastWin32Error());

这种错误检查是错误的。仅当 winapi 函数失败时调用 Marshal.GetLastWin32Error() 才有效。因此，一个坚如磐石的要求是首先检查 success 。如果函数实际成功，无论如何调用 GetLastWin32Error() 都会产生任意垃圾值。 ERROR_INVALID_FUNCTION 肯定有很高的垃圾值(value)。

当实际 出现错误时，代码也相当糟糕，它几乎没有发出足够的噪音，客户端代码可以轻松忽略无效的句柄值。正确的代码是:

       bool success = WinUsb_Initialize(...);
       if (!success) throw new System.ComponentModel.Win32Exception();

异常构造函数已调用 Marshal.GetLastWin32Error() 并将生成适当的本地化错误消息。