AttributeError: 'GPIBInstrument' object has no attribute 'flush'

Problem

The flush() method cannot be called on a GPIBInstrument object

I can do this from Labview, and the official NI VISA documentation says that viFlush() is valid for the following resource classes: GPIB INSTR, GPIB INTFC, Serial INSTR, TCPIP INSTR, TCPIP SOCKET, VXI INSTR, VXI SERVANT

From looking at the pyvisa code, it appears as though the only resource class that has flush() implemented is asynchronous serial.

Steps to reproduce

import visa
rm = visa.ResourceManager()
session = rm.open_resource('GPIB0::5::INSTR')
session.flush()

returns this error:

Traceback (most recent call last):
session.flush(0b00100000)
AttributeError: 'GPIBInstrument' object has no attribute 'flush'

Proposed fix

Implement flush() by calling viFlush() within the GPIBInstrument class, and any other objects in the list above where it’s safe to be called.

If you’d like that in the form of a pull request I can handle that, but wanted to ensure that this is indeed a bug and not a mis-interpretation on my end.

[MatthieuDartiailh]

VXI is not widely used with PyVISA (at least I never heard of anybody using it), so it is fine to skip the implementation.

[KM4YRI]

Nice, thanks!