For example, if you wanted to create a control that changes its appearance by cycling through a range of pictures, you would repeatedly call the function below (or a more terse equivalent):
{
int Val, Max, Min;
Val = GetCtlValue(ControlHandle);
Min = GetCtlMin(ControlHandle);
Max = GetCtlMax(ControlHandle);
Val++; /* Increment Val to move to the next picture in the series */