function callback using std::bind in ros 2 subscription

asked 2018-04-20 07:19:37 -0600

Skyking
151 ●18 ●24 ●28

Hi,

Using std::bind with rclcpp::Node::create_subscription() throws compilation errors.

For example, I cannot use

sub_input_ = node->create_subscription<sensor_msgs::msg::Imu>("input",
  std::bind(
      &input_surface_indices_callback,
      this, <argument1>,<argument2>));

However using lamdas as a callback function is ok in this case. Any help/information on this is welcome.

Comments

What about showing us such a "compilation error"? We cannot help you without you showing us what happened.

gvdhoorn ( 2018-04-20 07:33:39 -0600 )edit

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answered 2018-04-20 10:43:48 -0600

Karsten
643 ●9 ●18 ●23

I believe this is the same issue as reported in here: https://github.com/ros2/rclcpp/issues...

std::bind with additional arguments is not getting resolved correctly. However, I believe if you extract your std::bind to a std::function and then pass the function instance to the callback it will work.

std::function<void(std::shared_ptr<sensor_msgs::msg::Imu>)> fnc = std::bind(
   &input_surface_indices_callback, this, std::placeholders::_1, <argument1>, <argument2>);
sub_input_ = node->create_subscription<sensor_msgs::msg::Imu>("input", fnc);

I am assuming here that your callback has a signature like:

void input_surface_indices_callback(std::shared_ptr<sensor_msgs::msg::Imu>, Argument1T arg1, Argument2T arg2);

Could you try that out and see if it works for you?

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Comments

I was able to pass extra parameters to the callbacks in bouncy using the std::function method https://github.com/lucasw/v4l2ucp/blo... (though I'm probably going replace the subscribers with service/s later)