It works in Windows too. Many applications use it to "embed" other applications' window into their own UI. A non-gaming-related example is PuTTY and its various front-ends (SuperPuTTY and whatnot) but it (reportedly) also works for GL-enabled windows which is often used by "overlay"-type software (I think there's even a flag that can be passed to SDL which makes it attach to that window instead of creating its own. It's been a few years since I last used such features though)
Last edited by Darkstar; 10/02/16 10:45 AM.