I'm writting a driver for a Rigol oscilloscope using VISA with the USB port (scope firmware supports VISA).
How can you determine how many bytes are waiting to be read?
With the Visa-serial I can use "Number of bytes at serial port" but I can't find the equivalent for "plain" VISA.
I'm using a very high byte count with the VISA read vi to make sure I'm getting the full response but this seems a bit of a kludge.
So far the only way I can find is to catch the timeout error when no data is available.