How to communicate with USB device (EV3)

I am working on a Qt based application to interact with Lego Ev3 Mindstorm.

I am working on Windows 10 platform using Qt 5.14 and Visual Studio 2017;

I know the brick has a valid USB connection because the Lego application can control it.

I have tried using libusb but the bulk_transfer apparently is not supported on Windows. I can connect to the device in libusb but the transfer always fails.

I also tried hidapi. again I can connect to the device but canont write to it.

Is there a library that is known to work with Qt and windows USB devices?

Bruce

USB handles multiple different protocols. You need to identify what protocol Ev3 is using for communication and then you have to follow that protocol (it may be some kind of custom serial transmission) in your libusb code. bulk_transfer is probably not the protocol you want.