Trouble accessing Int32MultiArray message data in Arduino

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Hi everyone!

I am sending an Int32MultiArray message "act_msg" from Python, which I am trying to read in Arduino.

The topic over which the message is being broadcasted is "move_B1L".

Here is the Python code which is publishing two numbers (60 and 90) in an array. I have left out much of the code as this part is working fine:

act_msg = Int32MultiArray()
act_msg.data = [60, 90]
pub.publish(act_msg)

To confirm it is working, here is what rostopic echo move_B1L shows me:

layout:
   dim: []
   data_offset: 0
data: [60, 90]
---

I am now trying to read the contents of move_B1L in an Arduino callback function:

std_msgs::Int32MultiArray try1_msg;          //Setup test message of Int32MultiArray
ros::Publisher test("test", &try1_msg);       //Setup test message publisher

void B1LCallback(const std_msgs::Int32MultiArray& move_B1L){
  test.publish( &move_B1L );

I am simply getting Arduino to publish the same array it has received from Python, over the topic "test".

Now when I do try rostopic echo test, here is the output I get:

layout: 
  dim: []
  data_offset: 0
data: [29, 90]
---

The two arrays are not the same.

I am trying to assign each of the elements of move_B1L to a separate variable in Arduino, but for some reason I am not able to access the data inside the message.

For example, I followed the guidance on this link: https://github.com/ros-drivers/rosserial/issues/45 and tried to implement the following:

std_msgs::Int32MultiArray try1_msg;

long real_data_storage[2];

ros::Publisher test("test", &try1_msg);

void B1LCallback(const std_msgs::Int32MultiArray& move_B1L){
  try1_msg.data_length = 2;
  try1_msg.data = real_data_storage;
  try1_msg.data[0] = move_B1L.data[0];
  try1_msg.data[1] = move_B1L.data[1];
  test.publish( &try1_msg );

And this gives me something unexpected when I do rostopic echo test again:

layout: 
  dim: []
  data_offset: 0
data: [0, 90]
---

This is different from the previous run of rostopic echo test, even though nothing else has changed.

Can you please help me access the values inside the message correctly?

Thank you so much!

HM