Need correct syntax to call an actionlib service from a class member function.

asked 2013-10-15 12:18:11 -0600

rnunziata
711 ●145 ●164 ●190

updated 2013-10-23 01:05:15 -0600

What is the correct syntax to call an actionlib service from a class member function. As it is defined below I believe the var ac goes out of scope. But I am my attempts to move it outside being weak in c++ have failed.

void handelerSimpleGoal(const geometry_msgs::PoseStamped msg)
{
     typedef actionlib::SimpleActionClient<move_base_msgs::MoveBaseAction> MoveBaseClient;

     // find the coke can and use it as goal
     ros::ServiceClient client = n.serviceClient<gazebo_msgs::GetModelState>("/gazebo/get_model_state");
     gazebo_msgs::GetModelState getmodelstate;
     getmodelstate.request.model_name ="coke_can";
     client.call(getmodelstate);

     // send the new goal
     MoveBaseClient ac("move_base", true);
     move_base_msgs::MoveBaseGoal goal;
     goal.target_pose.header.frame_id = "map";
     goal.target_pose.header.stamp = ros::Time::now();
     goal.target_pose.pose = getmodelstate.response.pose;
     ac.sendGoal(goal);
}

answered 2013-10-23 02:54:45 -0600

skiesel

549 ●13 ●16 ●26 http://cs.unh.edu/~skiesel

I would imagine at some point you want to know the status of this issued request. The tutorial on using this in the navigation stack suggests that you wait for the result (which will block), then check the result to see what happened. "ac" will still go out of scope once the function finishes but at least this way you'll have all the information you need. Depending on your exact use case needs you can also increase the scope of that MoveBaseClient variable and avoid this issue. Anyway according to http://wiki.ros.org/navigation/Tutorials/SendingSimpleGoals :

  ac.waitForResult();

  if(ac.getState() == actionlib::SimpleClientGoalState::SUCCEEDED)
    ROS_INFO("Hooray, the base moved 1 meter forward");
  else
    ROS_INFO("The base failed to move forward 1 meter for some reason");

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I do not want to wait in my callback ..but not sure how to move the typedef and declaration outside the method. All my attempts have failed. Do you know how to do this ...this is my jest of my question.

rnunziata ( 2013-10-23 03:19:42 -0600 )edit

You can move the typedef out of the function, that shouldn't be an issue. The other situation is the object. If you REALLY want it to persist, you can declare it as a pointer outside the function, instantiate it in your main function, and access it in this callback.

skiesel ( 2013-10-23 04:25:35 -0600 )edit

I do not understand why many functions like action interface and time sync are not oop friendly. I should not have to jump though hoops to use these in a member class. Can this be treated as a ticket-able item?

rnunziata ( 2013-10-25 05:43:30 -0600 )edit

When you issue a goal, typically you want to know if it was achieved. As a result you need to wait for the execution to complete. On the other hand, if you do not care about those things, why do you care if "ac" goes out of scope and is cleaned up? sendGoal will complete before that happens?

skiesel ( 2013-10-25 08:50:28 -0600 )edit

I do care , I just want to check on it later and not in the issuing call back. But my question is not one of usage but why is it not callable from class method putting the handle in a class var. We are in a OOP. Anyway I think this topic is wondering.

rnunziata ( 2013-10-25 15:59:09 -0600 )edit

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Need correct syntax to call an actionlib service from a class member function.

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Need correct syntax to call an actionlib service from a class member function.