Detecting Multiple Keyboards/Mice

Hello, I am currently using SDL for collecting input in my engine. I know in the current version of SDL it is just assumed that there is one keyboard and one mouse. The API very clearly reflects this.

I do not know much about the internals of collecting input, nor OS API’s for such things. So I am curious, how complicated would it be to create an API that can distinguish between multiple mice/keyboards connected to the same system. Something that could be used for a split screen PC game, for example. Is that crazy? Would that not be cross-platform? Is that too niche?

I appreciate the links and watched most (but not all) of the video. While it’s great to hear the idea has occurred to the devs and thus the idea must not be TOO crazy, this is still somewhat lacking in detail on the subject on top of being 2 years old. Clearly the idea has hit the backburner. So most of my curiosity on the subject remains.

Slide 39 / 41

The video:

(look up the time yourself, towards the end)