title: libusb failing at getting string descriptor on some devices
body: <p>I am trying to get information about all attached devices.   </p>
  
  <p>This is my code:</p>
  
  <pre><code>libusb_device_descriptor desc;
  libusb_config_descriptor *conDesc;
  char szBuffer[256] = { 0 };
  unsigned char strDesc[256];
  libusb_device_handle *devHandle = NULL;
  int retVal = 0;
  __int64 i64Temp;
  DWORD dwProdId;
  DWORD dwProdId1;
  i64Temp = 13888;
  dwProdId = (DWORD)i64Temp;
  
  retVal = libusb_open(dev, &amp;devHandle);
  
  
  int r = libusb_get_device_descriptor(dev, &amp;desc);
  if (r &lt; 0)
  {
      cout &lt;&lt; "failed to get device descriptor" &lt;&lt; endl;
      return;
  }
  r = libusb_get_config_descriptor(dev, 0, &amp;conDesc);
  printf("Interface Class = %d\n", conDesc-&gt;interface-&gt;altsetting-&gt;bInterfaceClass);
  cout &lt;&lt; "Number of possible configurations: " &lt;&lt; (int)desc.bNumConfigurations &lt;&lt; "" &lt;&lt; endl;
  cout &lt;&lt; "Device Class: " &lt;&lt; desc.bDeviceClass &lt;&lt; endl;
  cout &lt;&lt; "Device Class: " &lt;&lt; desc.bDeviceSubClass &lt;&lt; endl;
  printf("Class = %d\n", desc.bDeviceClass);
  cout &lt;&lt; "VendorID: " &lt;&lt; desc.idVendor &lt;&lt; endl;
  cout &lt;&lt; "ProductID: " &lt;&lt; desc.idProduct &lt;&lt; endl;
  if (retVal == LIBUSB_SUCCESS)
  {
      retVal = libusb_get_string_descriptor_ascii(devHandle, desc.iManufacturer, strDesc, 256);
      printf("Manufacturer: %s\n", strDesc);
      retVal = libusb_get_string_descriptor_ascii(devHandle, desc.iSerialNumber, strDesc, 256);
      printf("SerialNumber: %s\n", strDesc);
      retVal = libusb_get_string_descriptor_ascii(devHandle, desc.iProduct, strDesc, 256);
      printf("Product: %s\n", strDesc);
      printf("\n\n");
  }
  else if (retVal != LIBUSB_SUCCESS)
  {
      printf("retVal failed");
      printf("\n\n");
  }
  </code></pre>
  
  <p>My code knows that there are 8 devices connected but it's getting manufacturer or serial number only on two of them. I would like to get this information for all of the attached devices.</p>