code: func SpinButtonNew(adjustment *Adjustment, climbRate float64, digits uint) (*SpinButton, error) {
  	c := C.gtk_spin_button_new(adjustment.native(),
  		C.gdouble(climbRate), C.guint(digits))
  	if c == nil {
  		return nil, nilPtrErr
  	}
  	return wrapSpinButton(glib.Take(unsafe.Pointer(c))), nil
  }
docs: // SpinButtonNew() is a wrapper around gtk_spin_button_new().