Not knowing SDL feels like someone having no idea what C++ or Unreal Engine is. I am curious how you managed to avoid learning about SDL despite being on hacker news.
I've literally never even heard the term SDL before this. I would say that it's nowhere near the same class of ubiquity as the other two examples you gave.
Granted that is trivially true because Unreal Engine itself and many, many other engines use SDL internally but still. So yeah, is is way MORE ubiquitous than Unreal Engine.
I guess there is just less awareness because SDL is a lower level detail that most people don't really need to care about. It just works and powers a huge chunk of our games and software.
Nothing wrong with not knowing about it, it is just interesting to me that even in tech spaces some people are not aware of SDL. I am sure there is a lot of things I don't know either.