I am attempting to change the display settings to “Duplicate” when I have 2 monitors connected to a PC?
Ie, I am attempting to select the following setting(outlined in red) but using a WinAPI function call.

My Problem: I dont know what WinAPI function call I use to change the display setting to “Duplicate”? I’ve googled and haven’t found any such function.
I am looking for a function that is supported on Windows 2000 or XP and up and not just a Windows Vista and up function. Does anyone know what WinAPI function call I use to achieve this?
I believe you want to use
ChangeDisplaySettingsEx. You set upDEVMODEstructures for both monitors, with thedmPositionmember set to(0, 0), and set (only) theDM_POSITIONflag, so all you do is change their relative positions, not things like resolution or bit depth.This is supposed to work back as far as Windows 2000.