Function gio_sys::g_menu_model_get_item_attribute

pub unsafe extern fn g_menu_model_get_item_attribute(model: *mut GMenuModel,
                                                     item_index: c_int,
                                                     attribute: *const c_char,
                                                     format_string: *const c_char,
                                                     ...)
                                                     -> gboolean