Multiplayer SDL 1.2 GAME

hello, I’m a student in the first year faculty I programmed a game in sdl 1.2 however the game is in single player mode but I want to put a multiplayer option: the screen is split in two is each player plays on the same card and the one who finishes first wins (both players are on two separate cards).
I would like to know if it’s possible or not and if someone has an idea like doing it.
Thank you.

This question not related to SDL directly. Multiplayer realization of your game depends on target platform.