NI's VISA32.DLL not compatible with Keysight's

HI:

I use the visa32.dll development tool

Declare Function viOpenDefaultRM Lib "VISA32.DLL" (ByRef sesn As Integer) As Integer

Declare Function viGetDefaultRM Lib "VISA32.DLL" Alias "#128" (ByRef sesn As Integer) As Integer

I find that if I use the "Keysight" driver. I can control the "GPIB0::20::INSTR" address of the instrument. But I use the "NI" driver. I will not be able to control the "GPIB0::20::INSTR" address of the instrument.

Why is this?

Are two visa32.dlls different?

I find the sizes of two visa32.dlls are different.