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

Nobody has claimed this yet.

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

#include
#include
#include
#include
#include

#include

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.

Start with the posted Arduino sketch, especially subscription_callback and the compiler diagnostic on the digitalWrite line. Compare the String message handling with the existing micro_ros_subscriber example and verify that the sketch compiles and responds correctly to the key_hit_event subscription.

Written by the indexing model from the issue text.