ros2.crystal. Is there anything wrong with adding the node to the executor before the subscriber has been properly initialized?

edit

Hi,

I am currently not sure if it is okay to add the node to the executor before the subscriber has been defined. Although the subscriber and publisher work without any issues, I just wanted to make sure there was not any unforeseen consequences in doing so.

The code I am working on is really large so I have attached a sample code.

using rclcpp::executors::MultiThreadedExecutor;
using builtin_interfaces::msg::Time;

std::shared_ptr<rclcpp::Node> master_node;

int value=0;


class test{

public:
    static void topic_callback(test_msgs::msg::Test::SharedPtr msg)
  {
    std::cout  <<" Subscriber Received [" << msg->data << "]" << std::endl;
    value = msg->data;
  }

};

int main()
{

  rclcpp::shutdown();
  test *t;
  t = new test();
  rclcpp::init(0, nullptr);

  MultiThreadedExecutor executor;
  master_node = rclcpp::Node::make_shared("MasterNode");
  executor.add_node(master_node); // Currently I have it here


  rclcpp::Publisher<test_msgs::msg::Test2>::SharedPtr publisher_;
  rclcpp::Subscription<test_msgs::msg::Test>::SharedPtr subscription_;


  subscription_ = master_node->create_subscription<test_msgs::msg::Test>("Test",t->topic_callback);  
  publisher_ =  master_node->create_publisher<test_msgs::msg::Test2>("Test2");
  rclcpp::Clock ros_clock(RCL_ROS_TIME);
  Time ros_now = ros_clock.now();
  // I seen examples and they mostly have it here
  std::thread executor_thread(std::bind(&MultiThreadedExecutor::spin, &executor));
  executor_thread.detach();


while(rclcpp::is_initialized)
  {
    auto message = test_msgs::msg::Test();
    message.header.stamp.nanosec = ros_now.nanosec;
    publisher_->publish(message);
    usleep(3000000);
  } 
    rclcpp::shutdown();

}

Would it be okay for me to keep the position of the add_node as is?