 -- Class: <gtk-vscale>
     Derives from <gtk-scale>.

     This class defines no direct slots.

 -- Function: gtk-vscale-new (adjustment <gtk-adjustment>) =>  (ret <gtk-widget>)
     Creates a new <gtk-vscale>.

     adjustment
          the <gtk-adjustment> which sets the range of the scale.

     ret
          a new <gtk-vscale>.

 -- Function: gtk-vscale-new-with-range (min double) (max double) (step double) =>  (ret <gtk-widget>)
     Creates a new vertical scale widget that lets the user input a number between MIN and MAX (including MIN and MAX) with the increment STEP. STEP must be nonzero; it's the distance the slider moves when using the arrow keys to adjust the scale value.

     Note that the way in which the precision is derived works best if STEP is a power of ten. If the resulting precision is not suitable for your needs, use gtk-scale-set-digits to correct it.

     min
          minimum value

     max
          maximum value

     step
          step increment (tick size) used with keyboard shortcuts

     ret
          a new <gtk-vscale>