An application sends the SBM_SETRANGE message to a scroll bar control to set the minimum and maximum position values for the control.
SBM_SETRANGE wParam = (WPARAM) nMinPos; // minimum scrolling position lParam = (LPARAM) nMaxPos; // maximum scrolling position
If the position of the scroll box changed, the return value is the previous position of the scroll box; otherwise, it is zero.
The default minimum and maximum position values are zero. The difference between the values specified by the nMinPos and nMaxPos parameters must not be greater than the value of MAXLONG.
If the minimum and maximum position values are equal, the scroll bar control is hidden and, in effect, disabled.