Callback function in thread

Question

I am receiving an error of error C2248: 'boost::mutex::mutex' : cannot access private member declared in class 'boost::mutex'

I have seen various variations of questions regarding the same error but can't not figure out the solution yet. I am trying to implement a callback function in a thread. The callback function is being called through a member function as shown below:

// KinectGrabber.h
class KinectGrabber{
private:
      mutable boost::mutex cloud_mutex_;
public:
      KinectGrabber() { };
      void run ();
      void cloud_cb_ (const CloudPtr& cloud);
};
// KinectGrabber.cpp
void KinectGrabber::cloud_cb_ (const CloudPtr& cloud)
{
    boost::mutex::scoped_lock lock (KinectGrabber::cloud_mutex_);
    // capturing the point cloud
}
void KinectGrabber::run() {
      // make callback function from member function
      boost::function<void (const CloudPtr&)> f =
      boost::bind (&KinectGrabber::cloud_cb_, this, _1);
      // connect callback function for desired signal. In this case its a point cloud with color values
      boost::signals2::connection c = interface->registerCallback (f);
}
int main (int argc, char** argv)
{
      KinectGrabber kinect_grabber;
      //kinect_grabber.run(); //this works
      boost::thread t1(&KinectGrabber::run,kinect_grabber); // doesnt work
      t1.interrupt;
      t1.join;
}

I am using multithreading as there are other functions which I need to run along with this. Thank you for your assistance.

score 1 · Answer 1 · edited May 23 '17 at 10:31

1

The run is a non static function you don't need to do it the way you are doing it just call the "cloud_cp" function in it I would have understand a bit of the code if run was static but it is not and it is using the this pointer ! you can stick with the code just keep the run function simple

and you will need to boost::bind at the boost::thread check this Using boost thread and a non-static class function

edited May 23 '17 at 10:31

Community

1
1

answered Nov 17 '13 at 12:01

Ibrahim

342
4
14

Can you please explain a bit more? I dont think I understand perfectly. – shunyo Nov 18 '13 at 15:10

score 1 · Accepted Answer · edited May 23 '17 at 11:50

Found out the answer after some ordeal. The problem for this kind of error is the class cannot be copied (Ref: boost mutex strange error with private member). So the solution is this:

boost::thread t1(&KinectGrabber::run,boost::ref(kinect_grabber));

The boost::thread by default copies the object by value thereby violating the non-copyable criterion. Changing it to passing by reference in the thread solves the error. Hopefully it helps all others.

Callback function in thread

2 Answers2