How to know if I use a touchscreen?


The question may looks strange but in fact I develop on a desktop environment where I use a mouse and I run the application on a target where I use a touchscreen.

In my application, I need to generate button click events but the problem is that I need to generate event.button.x and event.button.y coordinates in touchscreen resolution (4096x4096) and not screen resolution (1024x768).

Basically that’s not a problem but I just wonder how SDL2 guess that the coordinates must be adapted and how I can my self guess that I run on the target or on the desktop (so touchscreen or not touchscreen) to adapt coordinates calculation.
I could use a conditional build of course but is there any info in the SDL2 which helps to know it?