SetScrollRange
Sets the current position of a scroll box and, if requested, redraws the scroll bar to reflect the new position of the scroll box. Setting bRedraw to FALSE is useful whenever the scroll bar will be redrawn by a subsequent call to another function.
void SetScrollRange( int nBar, int nMinPos, int nMaxPos, BOOL bRedraw = TRUE )
The previous position of the scroll box.
origin.h