*SDL_GetTicks — Get the number of milliseconds since the SDL library initialization.

• SDL_Delay — Wait a specified number of milliseconds before returning.
• SDL_AddTimer — Add a timer which will call a callback after the specified number of milliseconds has elapsed.
• SDL_RemoveTimer — Remove a timer which was added with SDL_AddTimer.
• SDL_SetTimer — Set a callback to run after the specified number of milliseconds has elapsed.
  
  

SDL provides several cross-platform functions for dealing with time. It provides a way to get the current time, a way to wait a little while, and a simple timer mechanism. These functions give you two ways of moving an object every x milliseconds:

• Use a timer callback function. This may have the bad effect that it runs in a seperate thread or uses alarm signals, but it's easier to implement.
• Or you can get the number of milliseconds passed, and move the object if, for example, 30 ms passed.