value. gtkScaleAddMark(object, value, position, markup = NULL)objectGtkScalevaluepositionGTK_POS_TOP
is drawn above the scale, anything else below. For a vertical scale,
GTK_POS_LEFT is drawn to the left of the scale, anything else to the
right.markupNULL. [ allow-none ]markup is not NULL, text is shown next to the tick mark.
To remove marks from a scale, use gtkScaleClearMarks.
Since 2.16