(11-16-2012, 03:10 AM)Previous Wrote: Nintendo used the official Nintendo SDK for DS / 3DS, obviously.

It heavily depends on the game making tools you're using. Different utilities and programming languages may do it in different ways, if at all.
If it's meant to run on a PC on seperate monitors, I'd guess DirectX and OpenGL would have some functions to get that set up. If it's meant to run on a single screen on a PC, but in two parts, you'd use two different rendering views, but draw them on the same output. I'm not experienced with the technical aspects and coding of such things, though.

(11-16-2012, 05:11 AM)Previous Wrote: Can you be more specific and less general?

I don't think GameMaker supports multiple physical screens, but I haven't used it in ages. It does support multiple views for the single-screen variant, though. As for Flash, pretty much the same. You can't use multiple screens, but by using masked movievlips you could have multiple viewports on the same window.
C++, certainly, you should look into DirectX or OpenGL though or see if there are any libraries that make such a thing easier. I can't point you to anything specific, sorry.

(11-16-2012, 05:33 AM)Previous Wrote: I wouldn't know why someone would choose such a design for a PC game, where screens tend to be wider than high, but those should be doable with GM (don't ask me how, though!).
You basically need two seperate views or surfaces, rendering the map to one, the overworld on the over.

(11-17-2012, 06:17 PM)Previous Wrote: If you can do it, you can do it. But honestly, I wouldn't know why someone would want to have such a thing instead of having all the options accessible from within the running game. They may be a neat addition to equivalent in-game options, but shouldn't be the only way to go.

Here, you'd use files to safe your options and configurations. These files would be editable by your configurator program and would be read by the game.