[PC_HOST]<->[RPI]<->[STM32] ROS2 et Micro-ROS  

void subscription_callback(const void * msgin)
{
  const std_msgs__msg__String * msg = (const std_msgs__msg__String *)msgin;

  // Process message
  printf("Received from HOST: %s\n\r", msg->data);
}


void microros_task(void *argument)
{
  rmw_uros_set_custom_transport( true, (void *) &huart1, cubemx_transport_open,  cubemx_transport_close,  cubemx_transport_write, cubemx_transport_read);

  rcl_allocator_t freeRTOS_allocator = rcutils_get_zero_initialized_allocator();
  freeRTOS_allocator.allocate = microros_allocate;
  freeRTOS_allocator.deallocate = microros_deallocate;
  freeRTOS_allocator.reallocate = microros_reallocate;
  freeRTOS_allocator.zero_allocate =  microros_zero_allocate;

  if (!rcutils_set_default_allocator(&freeRTOS_allocator)) {
      printf("Error on default allocators (line %d)\n", __LINE__);
  }

  // micro-ROS app
  rclc_support_t support;
  rcl_allocator_t allocator;
  allocator = rcl_get_default_allocator();

  // create node
  rcl_node_t node;
  rcl_node_options_t node_ops = rcl_node_get_default_options();
  rcl_init_options_t init_options = rcl_get_zero_initialized_init_options();
  rcl_init_options_init(&init_options, allocator);
  rcl_init_options_set_domain_id(&init_options, ROS_DOMAIN_ID);

  rclc_support_init_with_options(&support, 0, NULL, &init_options, &allocator);
  rclc_node_init_default(&node, "STM32_Node","", &support);

  // create publisher
  rcl_publisher_t publisher;
  std_msgs__msg__String sensor_dist_back_msg;
  rclc_publisher_init_default(&publisher, &node, ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, String),"/sensor/dist_back");

  // create subscriber
  rcl_subscription_t subscriber;
  std_msgs__msg__String str_msg;
  rclc_subscription_init_default(&subscriber,&node,ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, String),"/command/move");
  // Add subscription to the executor
  rclc_executor_t executor;
  rclc_executor_init(&executor, &support.context, 1, &allocator); // ! 'NUMBER OF HANDLES' A MODIFIER EN FONCTION DU NOMBRE DE TOPICS
  rclc_executor_add_subscription(&executor, &subscriber, &str_msg, &subscription_callback, ON_NEW_DATA);

  str_msg.data.data = (char * ) malloc(ARRAY_LEN * sizeof(char));
  str_msg.data.size = 0;
  str_msg.data.capacity = ARRAY_LEN;

  for(;;)
  {
	  sprintf(str_msg.data.data, "from STM32 : mes_vl53 : #%d", (int32_t)mes_vl53);
	  str_msg.data.size = strlen(str_msg.data.data);

      rcl_ret_t ret = rcl_publish(&publisher, &str_msg, NULL);

		if (ret != RCL_RET_OK)
		{
		  printf("Error publishing (line %d)\n\r", __LINE__);
		}
    rclc_executor_spin_some(&executor, RCL_MS_TO_NS(10));
    osDelay(10);
  }
}