code: func AdjustmentNew(value, lower, upper, stepIncrement, pageIncrement, pageSize float64) (*Adjustment, error) {
  	c := C.gtk_adjustment_new(C.gdouble(value),
  		C.gdouble(lower),
  		C.gdouble(upper),
  		C.gdouble(stepIncrement),
  		C.gdouble(pageIncrement),
  		C.gdouble(pageSize))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	obj := glib.Take(unsafe.Pointer(c))
  	return wrapAdjustment(obj), nil
  }
docs: // AdjustmentNew is a wrapper around gtk_adjustment_new().