I have a built my own steering wheel and motion platform that I would like to connect to popular car racing games (e.g. iRacing, Dirt Rally). I need to read data such as the car's acceleration (to send to the motion platform) from these games and send information such as steering wheel's angle to the game. I have written an SDK in C++ to communicate with my steering will and motion platform. Now I need to interface different games with to that SDK. 

I searched quite a bit but could not find much information about how this is generally done. Do game developers provide some sort of extension which allows third party hardware developers to communicate with their game? 

Any guidance from the community is much appreciated.

Kam