Thread: ROS subscriber callback as member function does not get called

I can't see the solution for the problem and it doesn't even say what the problem actually was, so you're going to have to post some code. Put a compilable example that is as simple as possible while still exhibiting the problem.

> There is already a thread with exactly the same problem I have, but the answer to solve the problem isn't stated at the end.
So you were hoping to score a quick homework win by googling code, found something almost there - pulse racing as you scrolled down to reveal the answer to your homework, only for your hopes to be dashed on the rock of disappointment.

> Anyone has an idea about how to solve this?
Well the OP of the thread did.

Google plus "does anyone know" won't make you a programmer.

No need to be rude, this is the first time I post a thread in a forum. Sorry for not providing enough information.

Here is a short version of my code. It is I believe pretty much the same as the similar thread I referred to. If I'm not doing exactly the same thing, I don't know what's different. Since I removed most of it for briefty, I doubt it will compile, but the main parts are there.

Code:

int main( int argc, char **argv )
{
    // Initialize the ROS system
    ros::init( argc, argv, "elikos_aiAgent" );

    // Establish this program as a ROS node
    ros::NodeHandle nh;
    ros::Rate r(30);    //10 hz

    // Create the quad AI Agent
    elikos_ai::Agent agent(&nh);
    agent.init();

    while (ros::ok())
    {
        // stuff

        r.sleep();
    }

    agent.destroy();
}

class Agent
{

public:

    Agent( ros::NodeHandle* nh );
    ~Agent();
    void init();
    void destroy();
    void run();

    void receiveRobotsPosCallback( const elikos_ros::RobotsPos& msg );

private:
    ros::NodeHandle& nh_;

    void setSubscribers();

    std::map<std::string, ros::Publisher> rosPublishers_;
     std::map<std::string, ros::Subscriber> rosSubscribers_;

    // I've tested with this version too (the subscriber not being in a map)
    // ros::Subscriber sub_;
};

Agent::Agent( ros::NodeHandle* nh ) : nh_(*nh)
{}

void Agent::init()
{
    setSubscribers();
}

void Agent::setSubscribers()
{
    ROS_INFO_STREAM( "Agent::setSubscribers" );
    // Subscribe to all robots' positions' topics
    std::string robotsPosTopic = TOPICS_NAMES[robotsPos];
     ros::Subscriber sub =  nh_.subscribe(robotsPosTopic, 1000,  &Agent::receiveRobotsPosCallback, this );
    rosSubscribers_.insert( std::pair<std::string,ros::Subscriber>(robotsPosTopic, sub) );
    ROS_INFO_STREAM( "Agent::setSubscribers, end" );

    // I've tested with this version too (the subscriber not being in a map)
    // sub_ = nh_.subscribe(robotsPosTopic, 1000, &Agent::receiveRobotsPosCallback, this );
}

void Agent::receiveRobotsPosCallback( const elikos_ros::RobotsPos& msg )
{
    std::cout << "AGENT CALLBACK" << std::endl;
    ROS_INFO_STREAM( "Agent::callback -- Push RobotsPos message" );
    queueRobotsPos_.push( msg );
}

With this code, here are the console logs (with ROS_INFO_STREAM) I get:

The terminal running the ai_agent node (executable):

[ INFO] [1425144919.193049638]: Agent::setSubscribers
[ INFO] [1425144919.198125285]: Agent::setSubscribers, end

In another terminal, I checked if ROS receives any elikos_ros::RobotsPos messages at all, and it does. This means that any node subscribed to the RobotsPos topic should see their callback function called (where my program fails).

I tried several variations but none made it work, though I followed the given tutorials from the library and discussed it with coworkers. The library tutorials :

roscpp/Overview/Publishers and Subscribers - ROS Wiki (see point 2.3.2)

As in the previous thread, it was suggested to look into the ros::NodeHandle::subscribe() function, I tried to find the source but only managed to find the header file and couldn't find anything from this point:

roscpp: node_handle.h Source File

I tried the solution in this post, but it didn't work:

Subscriber callback not being called in C++ - ROS Answers: Open Source Q&A Forum

Thanks for you help