字符串信息

2万 · 2014-6-23 19:59

以前从没有做过USB，头给我一个Cypress的Ezusb的控制面板程序，让我读然后模仿写一个自己的应用程序，我看的头大了，当我我模仿写到获取字符串信息时，原程序发送了两次DeviceIoControl命令，为什么呢要两次呢？

2万 · 2014-6-23 20:01

原代码如下：
char    temp[64]    = " ";
GET_STRING_DESCRIPTOR_IN input;
pvBuffer = malloc (sizeof (Usb_String_Descriptor) + 128);
if (bOpenDriver (&hDevice, pcDriverName) != TRUE)    // Open the driver
{
      显示信息
}
#ifdef USING_MFC
input.Index = (UCHAR) pTh-> index;
input.LanguageId = 27; // NOTE: frameworks ignores it anyway
wsprintf (temp, "GetStringDescripter: Index=%d ", input.Index);
EzSendMessage (hOutputBox, LB_ADDSTRING, 0, (LPARAM)emp);
#endif
// Get the first bytes of the descriptor to determine the size of
// the entire descriptor.
if (hDevice != NULL)
{// Perform the Get-Descriptor IOCTL
      bResult = DeviceIoControl (hDevice,
                  IOCTL_Ezusb_GET_STRING_DESCRIPTOR,
&input,
sizeof (GET_STRING_DESCRIPTOR_IN),
pvBuffer,
sizeof (Usb_String_Descriptor),
(unsigned long *)&nBytes,
NULL);
}/* if valid driver handle */
if (bResult!=TRUE)
{// This will happen with no string defined
      EzSendMessage (hOutputBox, LB_ADDSTRING, 0, (LPARAM) "Get String Descriptor Failed ");
      //ShowSystemError(hOutputBox);
      CloseHandle (hDevice);
      free (pvBuffer);
}/* if */
ulLength = GET_STRING_DESCRIPTOR_LENGTH(pvBuffer);
assert (ulLength > = 0);
// Now get the entire descriptor
pvBuffer = realloc (pvBuffer, ulLength);
if (pvBuffer)
{
   // Perform the Get-Descriptor IOCTL
   bResult = DeviceIoControl (hDevice,
IOCTL_Ezusb_GET_STRING_DESCRIPTOR,
&input,
ulLength,
pvBuffer,
ulLength,
(unsigned long *)&nBytes,
NULL);
if (bResult==TRUE)
{
   显示信息
}

1万 · 2014-6-23 20:02

驱动用CB写吗？不少介绍都是用VC＋DS，我不懂。

2万 · 2014-6-23 20:03

请教一下CB6和DS2.1能配合使用开发WIN2000 和XP的驱动程序吗？

2万 · 2014-6-23 20:05

说真的我也知道，我是用BCB写应用程序这部分，驱动不是我写的，我们用已经有的，我这个地方很晕，谢谢各位支持

2万 · 2014-6-23 20:07

typedef struct _GET_STRING_DESCRIPTOR_IN
{
UCHAR Index;
USHORT LanguageId;
} GET_STRING_DESCRIPTOR_IN, *PGET_STRING_DESCRIPTOR_IN;
这是驱动里的GET_STRING_DESCRIPTOR_IN结构