Hi,

I have been trying to control the dynamixel using the data received by the subscriber of msg type Int64MultiArray. I do not know what the problem is, I could not able to make it work. I could able to publish the array but not subscribe. When the msg type of subscriber is changed to Int32 it is working fine but I need to get a array of data( six values).

Kindly inform what is the problem or any alternate methods.

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

void subscription_callback(const void * msgin)
{ 

  const std_msgs__msg__Int64MultiArray * goal_vel = (const std_msgs__msg__Int64MultiArray *)msgin;
  int64_t left_front; 

    value[0] = int64_t(goal_vel->data.data[0]);
    value[1] = goal_vel->data.data[1];
    left_front = (goal_vel->data.data[0]);

    //left_front = int32_t(msg->data);
    dxl.setGoalVelocity(DXL_ID,value[0]);

   }

void setup() {
  // put your setup code here, to run once:
    set_microros_transports();

    allocator = rcl_get_default_allocator();

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

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

    //create publisher
    RCCHECK(rclc_publisher_init_default(&publisher, &node, 
      ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int64MultiArray), "ticks"));

     // create subscriber
    RCCHECK(rclc_subscription_init_default(&subscriber,&node,
    ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int64MultiArray),  "drive_cmd"));

    // create executor
    RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
    RCCHECK(rclc_executor_add_timer(&executor, &timer));
    RCCHECK(rclc_executor_add_subscription(&executor, &subscriber, &goal_vel, &subscription_callback, ON_NEW_DATA));

      Serial.begin(115200);
    dxl.begin(1000000);
    dxl.setPortProtocolVersion(DXL_PROTOCOL_VERSION);

    //dxl.ping(DXL_ID);
    dxl.torqueOff(DXL_ID);
  dxl.setOperatingMode(DXL_ID, OP_VELOCITY);
  dxl.torqueOn(DXL_ID);
  dxl.setGoalVelocity(DXL_ID,20);

  goal_vel = std_msgs__msg__Int64MultiArray__create();
  ticks = std_msgs__msg__Int64MultiArray__create();

  goal_vel->data.data = (int64_t*)malloc(sizeof(value));
  ticks->data.data = (int64_t*)malloc(sizeof(array_tic)); 

  ticks->data.size = sizeof(array_tic)/sizeof(int64_t);memcpy(ticks->data.data,array_tic,sizeof(array_tic));
  goal_vel->data.size = sizeof(value)/sizeof(int64_t);memcpy(goal_vel->data.data, value,sizeof(value));
}

void loop() {
  // put your main code here, to run repeatedly:
    delay(100);
    array_tic[0]= left_tick;
    array_tic[1] = right_tick;
    left_tick =  dxl.getPresentPosition(DXL_ID);  
    right_tick =  dxl.getPresentPosition(2); 
    ticks->data.data = array_tic;  

    RCSOFTCHECK(rcl_publish(&publisher, ticks, NULL));
    RCSOFTCHECK(rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100)));
}