Problem getting USB_BANDWIDTH_INFO structure - windows

Question

I'm writing a Windows application in C++ reading images from an external USB cam and displaying them (which works nicely). I like to monitor the used USB bandwidth at the same time. I know that there exists a USB_BANDWIDTH_INFO structure (https://learn.microsoft.com/en-us/windows/win32/api/usbuser/ns-usbuser-usb_bandwidth_info), but I have no clue how to use it. More precisely: The structure itself is pretty clear, but how do I get/read it (didn't find any example code explaining that)?

Answer 1

According to the MSDN:
The USB_BANDWIDTH_INFO structure is used with the IOCTL_USB_USER_REQUEST I/O control request to retrieve information about the allocated bandwidth.
So you need to call DeviceIoControl with IOCTL_USB_USER_REQUEST.
Refer to the official example, you can find:
GetHostControllerInfo(
HANDLE hHCDev,
PUSBHOSTCONTROLLERINFO hcInfo)
{
USBUSER_CONTROLLER_INFO_0 UsbControllerInfo;
DWORD dwError = 0;
DWORD dwBytes = 0;
BOOL bSuccess = FALSE;
memset(&UsbControllerInfo, 0, sizeof(UsbControllerInfo));
// set the header and request sizes
UsbControllerInfo.Header.UsbUserRequest = USBUSER_GET_CONTROLLER_INFO_0;
UsbControllerInfo.Header.RequestBufferLength = sizeof(UsbControllerInfo);
//
// Query for the USB_CONTROLLER_INFO_0 structure
//
bSuccess = DeviceIoControl(hHCDev,
IOCTL_USB_USER_REQUEST,
&UsbControllerInfo,
sizeof(UsbControllerInfo),
&UsbControllerInfo,
sizeof(UsbControllerInfo),
&dwBytes,
NULL);
if (!bSuccess)
{
dwError = GetLastError();
OOPS();
}
else
{
hcInfo->ControllerInfo = (PUSB_CONTROLLER_INFO_0) ALLOC(sizeof(USB_CONTROLLER_INFO_0));
if(NULL == hcInfo->ControllerInfo)
{
dwError = GetLastError();
OOPS();
}
else
{
// copy the data into our USB Host Controller's info structure
memcpy(hcInfo->ControllerInfo, &UsbControllerInfo.Info0, sizeof(USB_CONTROLLER_INFO_0));
}
}
return dwError;
}
You can modify it like:
USBUSER_CONTROLLER_INFO_0 UsbControllerInfo;
UsbControllerInfo.Header.UsbUserRequest = USBUSER_GET_BANDWIDTH_INFORMATION;
UsbControllerInfo.Header.RequestBufferLength = sizeof(UsbControllerInfo);
USB_BANDWIDTH_INFO UsbBandInfo{};
DWORD dwError = 0;
DWORD dwBytes = 0;
BOOL bSuccess = FALSE;
bSuccess = DeviceIoControl(hHCDev,
IOCTL_USB_USER_REQUEST,
&UsbControllerInfo,
sizeof(UsbControllerInfo),
&UsbBandInfo,
sizeof(USB_BANDWIDTH_INFO),
&dwBytes,
NULL);