[Libusb-win32-devel] access to usb_config_descriptor

[<mmi...@gm...>]

Hello,

I am working in a project that needs to use libusb to avoid automatic
detection of some usb devices when connected.

I have downloaded and instaled libusb-win32-filter-bin-20060827.exe.  But I
can't make work the example application, I have an "access violation error"
when trying to access to usb_configuration_descriptor, here is the code:

struct usb_bus *bus;
 struct usb_device *dev;
 const struct usb_version *version;

 edit_printf_init();

 usb_find_devices();

 version = usb_get_version();

 if(version)
   {
     edit_printf("DLL version:\t%d.%d.%d.%d\r\n",
                 version->dll.major, version->dll.minor,
                 version->dll.micro, version->dll.nano);

     edit_printf("Driver version:\t%d.%d.%d.%d\r\n\r\n",
                 version->driver.major, version->driver.minor,
                 version->driver.micro, version->driver.nano);
   }

 edit_printf("bus/device  idVendor/idProduct\r\n");

 for (bus = usb_get_busses(); bus; bus = bus->next) {
   for (dev = bus->devices; dev; dev = dev->next) {
     int ret, i;
     char string[256];
     usb_dev_handle *udev;

     edit_printf("%s/%s     %04X/%04X\r\n", bus->dirname, dev->filename,
                 dev->descriptor.idVendor, dev->descriptor.idProduct);
     udev = usb_open(dev);
          if (udev) {
       if (dev->descriptor.iManufacturer) {
         ret = usb_get_string_simple(udev, dev->descriptor.iManufacturer,
                                     string, sizeof(string));
         if (ret > 0)
           edit_printf("- Manufacturer : %s\r\n", string);
         else
           edit_printf("- Unable to fetch manufacturer string\r\n");
       }

       if (dev->descriptor.iProduct) {
         ret = usb_get_string_simple(udev, dev->descriptor.iProduct, string,

                                     sizeof(string));
         if (ret > 0)
           edit_printf("- Product      : %s\r\n", string);
         else
           edit_printf("- Unable to fetch product string\r\n");
       }

       if (dev->descriptor.iSerialNumber) {
         ret = usb_get_string_simple(udev, dev->descriptor.iSerialNumber,
                                     string, sizeof(string));
         if (ret > 0)
           edit_printf("- Serial Number: %s\r\n", string);
         else
           edit_printf("- Unable to fetch serial number string\r\n");
       }

       usb_close (udev);
     }

     if (!dev->config) {
       edit_printf("  Couldn't retrieve descriptors\r\n");
       continue;
     }

     for (i = 0; i < dev->descriptor.bNumConfigurations; i++)
       print_configuration(&dev->config[i]);
   }
 }

 SendMessage(edit_box, WM_SETTEXT, 0, (LPARAM) edit_buffer);
 edit_printf_free();
}

dev->config is not NULL, but when I try to acces to his content I have the
acces violation error. That makes me think that the configuration is not in
the structure, but Why not??

I would appereciate very much your help.

Regards,
Mar