code: func (v *LevelBar) GetOffsetValue(name string) (float64, bool) {
  	cstr := C.CString(name)
  	defer C.free(unsafe.Pointer(cstr))
  	var value C.gdouble
  	c := C.gtk_level_bar_get_offset_value(v.native(), (*C.gchar)(cstr), &value)
  	return float64(value), gobool(c)
  }
docs: // GetOffsetValue() is a wrapper around gtk_level_bar_get_offset_value().