ros2将多个topic的消息写进文件

[3202319872]

通过建立多个监听者将topic的消息订阅到想把他们写进文件，但是ros2的订阅函数都是静态的，我应该怎么才能将这些不同的消息整合到一起处理呢？

#include <memory>
#include <iostream>
#include <fstream>

#include "rclcpp/rclcpp.hpp"
#include "auto_move_msgs/msg/car_message.hpp"
#include "auto_move_msgs/msg/imu_message.hpp"
#include "auto_move_msgs/msg/save_message.hpp"
using std::placeholders::_1;

//struct save_message{
//    float speed;
//    float torque;
//    float acceleration;
//};

class DataCollector : public rclcpp::Node
{
public:
    auto_move_msgs::msg::SaveMessage saveMessage;
    DataCollector()
            : Node("data_collector_subscriber")
    {
        car_subscription_ = this->create_subscription<auto_move_msgs::msg::CarMessage>(
                "car_message", 10, std::bind(&DataCollector::car_message_callback, this, _1));

        imu_subscription_ = this->create_subscription<auto_move_msgs::msg::ImuMessage>(
                "imu_message", 10, std::bind(&DataCollector::imu_message_callback, this, _1));
        //RCLCPP_INFO(this->get_logger(),"I will write data to file");
        //ofstream

    }

private:
    void car_message_callback(const auto_move_msgs::msg::CarMessage::SharedPtr car_msg) const
    {
        RCLCPP_INFO(this->get_logger(), "I heard car message: '%f' , '%f'", car_msg->speed,car_msg->torque);
        saveMessage.speed = car_msg->speed;
        saveMessage.torque = car_msg->torque;
    }

    void imu_message_callback(const auto_move_msgs::msg::ImuMessage::SharedPtr imu_msg) const
    {
        RCLCPP_INFO(this->get_logger(), "I heard imu message: '%f'", imu_msg->acceleration);
        saveMessage.acceleration = imu_msg->acceleration;
    }

    rclcpp::Subscription<auto_move_msgs::msg::CarMessage>::SharedPtr car_subscription_;
    rclcpp::Subscription<auto_move_msgs::msg::ImuMessage>::SharedPtr imu_subscription_;
};
int main(int argc, char * argv[])
{
    rclcpp::init(argc, argv);
    rclcpp::spin(std::make_shared<DataCollector>());
    rclcpp::shutdown();
    return 0;
}

上面是我的代码我想将多个topic保存进我自定义的消息里然后写进文件，大家有什么好的建议吗

[3202319872]

数据处理问题已经解决实际上是一个cpp语法问题

    auto_move_msgs::msg::SaveMessage saveData;
    auto_move_msgs::msg::SaveMessage & saveMessage = saveData;

用一个引用就可以修改数据本身了

写进文件的操作正在解决，大家有什么好的建议可以给我留言