How to get usb mass storage size using libusb library? - libusb

Question

I am finding out usb mass storage related information using libusb library.
But don't know how to get usb mass storage size?
My tryout is:
void printdev(libusb_device *dev);
int main()
{
libusb_device **devs;
libusb_context *ctx = NULL; //a libusb session
int r;
ssize_t cnt; //holding number of devices in list
r = libusb_init(&ctx); //initialize a library session
if(r < 0)
{
cout<<"Init Error "<<r<<endl; //there was an error
return 1;
}
libusb_set_debug(ctx, 3); //set verbosity level to 3, as suggested in the documentation
cnt = libusb_get_device_list(ctx, &devs); //get the list of devices
if(cnt < 0)
{
cout<<"Get Device Error"<<endl; //there was an error
}
cout<<cnt<<" Devices in list."<<endl; //print total number of usb devices
int i;
for(i = 0; i < cnt; i++)
{
printdev(devs[i]);
}
libusb_free_device_list(devs, 1); //free the list, unref the devices in it
libusb_exit(ctx); //close the session
return 0;
}
void printdev(libusb_device *dev)
{
libusb_device_descriptor desc;
libusb_config_descriptor *conDesc;
char szBuffer[256] = {0};
unsigned char strDesc[256];
libusb_device_handle *devHandle = NULL;
int retVal;
__int64 i64Temp;
DWORD dwProdId;
DWORD dwProdId1;
i64Temp = 13888;
dwProdId = (DWORD)i64Temp;
retVal = libusb_open (dev, &devHandle);
if (retVal != LIBUSB_SUCCESS)
return;
int r = libusb_get_device_descriptor(dev, &desc);
if (r < 0)
{
cout<<"failed to get device descriptor"<<endl;
return;
}
r = libusb_get_config_descriptor(dev, 0, &conDesc);
printf("Interface Class = %d\n", conDesc->interface->altsetting->bInterfaceClass);
cout<<"Number of possible configurations: "<<(int)desc.bNumConfigurations<<" ";
// cout<<"Device Class: "<<desc.bDeviceClass<<endl;
// cout<<"Device Class: "<<desc.bDeviceSubClass<<endl;
printf("Class = %d\n", desc.bDeviceClass);
cout<<"VendorID: "<<desc.idVendor<<endl;
cout<<"ProductID: "<<desc.idProduct<<endl;
dwProdId1 = (DWORD)desc.idProduct;
if (dwProdId1 == dwProdId)
{
printf("in if\n");
}
else
{
printf("in else\n");
}
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");
}