ros2_tracing/tracetools_test/src/test_timer.cpp

#include <memory>
#include <chrono>

#include "rclcpp/rclcpp.hpp"

using namespace std::chrono_literals;

class TimerNode : public rclcpp::Node
{
public:
  explicit TimerNode(rclcpp::NodeOptions options)
  : Node("timer_node", options)
  {
    is_done_ = false;
    timer_ = this->create_wall_timer(
      1ms,
      std::bind(&TimerNode::timer_callback, this));
  }

private:
  void timer_callback()
  {
    if (is_done_) {
      rclcpp::shutdown();
    } else {
      is_done_ = true;
    }
  }

  rclcpp::TimerBase::SharedPtr timer_;
  bool is_done_;
};

int main(int argc, char * argv[])
{
  rclcpp::init(argc, argv);

  rclcpp::executors::SingleThreadedExecutor exec;
  auto timer_node = std::make_shared<TimerNode>(rclcpp::NodeOptions());
  exec.add_node(timer_node);

  printf("spinning\n");
  exec.spin();

  // Will actually be called inside the timer's callback
  rclcpp::shutdown();
  return 0;
}