Want to rewrite the micro_ros_subscriber for example_interfaces/msg/String.

[drinkBr]

Hi, I want to rewrite the micro_ros_subscriber for example_interfaces/msg/String. However, when I tried to modify it myself, I encountered an error and couldn't proceed any further. I would like to know how to resolve this issue.

The operating environment ・ArduinoIDE2.1.1 ・Arduino Due

program <

#include <micro_ros_arduino.h>

#include <stdio.h>
#include <rcl/rcl.h>
#include <rcl/error_handling.h>
#include <rclc/rclc.h>
#include <rclc/executor.h>

#include <example_interfaces/msg/string.h>

rcl_subscription_t subscriber;
example_interfaces__msg__String msg;
rclc_executor_t executor;
rclc_support_t support;
rcl_allocator_t allocator;
rcl_node_t node;
rcl_timer_t timer;

#define LED_PIN 13

#define RCCHECK(fn) { rcl_ret_t temp_rc = fn; if((temp_rc != RCL_RET_OK)){error_loop();}}
#define RCSOFTCHECK(fn) { rcl_ret_t temp_rc = fn; if((temp_rc != RCL_RET_OK)){}}


void error_loop(){
  while(1){
    digitalWrite(LED_PIN, !digitalRead(LED_PIN));
    delay(100);
  }
}

void subscription_callback(const void * msgin)
{  
  const example_interfaces__msg__String * msg = (const example_interfaces__msg__String *)msgin;
  digitalWrite(LED_PIN, (msg->data = "0") ? LOW : HIGH);  
}

void setup() {
  set_microros_transports();
  
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, HIGH);  
  
  delay(2000);

  allocator = rcl_get_default_allocator();

  //create init_options
  RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));

  // create node
  RCCHECK(rclc_node_init_default(&node, "micro_ros_arduino_node", "", &support));

  // create subscriber
  RCCHECK(rclc_subscription_init_default(
    &subscriber,
    &node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(example_interfaces, msg, String),
    "key_hit_event"));

  // create executor
  RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
  RCCHECK(rclc_executor_add_subscription(&executor, &subscriber, &msg, &subscription_callback, ON_NEW_DATA));
}

void loop() {
  delay(100);
  RCCHECK(rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100)));
}

Error message

rror: no match for 'operator=' (operand types are 'const rosidl_runtime_c__String' and 'const char [2]')
   digitalWrite(LED_PIN, (msg->data = "0") ? LOW : HIGH);  
                                    ^

Thank you.