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.