std::tie 如何返回多个值

假设有两个变量，需要赋值

NodeOptions node_options;
TrajectoryOptions trajectory_options;

我们可以一次性通过std::tie 进行赋值

std::tie(node_options, trajectory_options) =
      LoadOptions(FLAGS_configuration_directory, FLAGS_configuration_basename);

其中LoadOption的定义和返回值应该为

std::tuple<NodeOptions, TrajectoryOptions> LoadOptions(
    const std::string& configuration_directory,
    const std::string& configuration_basename) {
    ...
    return std::make_tuple(CreateNodeOptions(&lua_parameter_dictionary),
                         CreateTrajectoryOptions(&lua_parameter_dictionary));