Function screen_scroll_area 

pub unsafe extern "C" fn screen_scroll_area(
    x0: i16,
    y0: i16,
    x1: i16,
    y1: i16,
    lines: i16,
) -> u32

Scroll lines within a region on the display

This function behaves in the same way as screen_scroll, except that you specify a rectangular region within which to scroll lines instead of a start line.

This function uses the following values of errno when an error state is reached: EACCESS - Another resource is currently trying to access the screen mutex.

\param x0, y0 The (x,y) coordinates of the first corner of the rectangular region \param x1, y1 The (x,y) coordinates of the second corner of the rectangular region \param lines The number of lines to scroll upwards

\return 1 if there were no errors, or PROS_ERR if an error occured taking or returning the screen mutex.