If you wish to use SDL's function-calling timer, you must use the "SDL_INIT_TIMER" flag when initializing SDL:
Then you can call "SDL_SetTimer()" to have a particular function executed after a certain interval of time:SDL_Init(SDL_INIT_TIMER);
Uint32 callback(Uint32 interval)
{
...
return(interval);
}
...
SDL_SetTimer(interval, callback);
Every "interval" milliseconds, callback will be called.