Mainwindow closes when I close PCL window.

[surajj4837]

@jsulm

void MainWindow::on_pushButton_clicked()
{
    pcl::PointCloud<pcl::PointXYZ>::Ptr cloud (new pcl::PointCloud<pcl::PointXYZ>);
    pcl::io::loadPCDFile ("000000.pcd", *cloud);

    pcl::visualization::CloudViewer viewer("Cloud Viewer");

    //blocks until the cloud is actually rendered
    viewer.showCloud(cloud);

    //use the following functions to get access to the underlying more advanced/powerful
    //PCLVisualizer

    //This will only get called once
    viewer.runOnVisualizationThreadOnce (viewerOneOff);

    //This will get called once per visualization iteration
    viewer.runOnVisualizationThread (viewerPsycho);
    while (!viewer.wasStopped ())
    {
        //you can also do cool processing here
        //FIXME: Note that this is running in a separate thread from viewerPsycho
        //and you should guard against race conditions yourself...
        user_data++;
    }

    std::cout << "Quit" << std::endl;

    viewer.~CloudViewer();
    
}

[JonB]

@surajj4837 said in Mainwindow closes when I close PCL window.:

viewer.~CloudViewer();

Ummm??

[jsulm]

@surajj4837 As I thought: viewer is allocated on the STACK not heap. So, no need to delete it!
Remove viewer.~CloudViewer();

[surajj4837]

@jsulm That was the original problem I started with. The following statement was not there earlier

viewer.~CloudViewer();

But when I clicked on close button of viewer the cloudviewer window still existed on screen, so I tried closing through code. But that raised the error.

[surajj4837]

@JonB

This viewer declaration is in line #55:

pcl::visualization::CloudViewer viewer("Cloud Viewer");

When destructor is called the execution jumps to that line.

[jsulm]

@surajj4837 said in Mainwindow closes when I close PCL window.:

But when I clicked on close button of viewer the cloudviewer window still existed on screen

Then debug your code instead of doing strange things like deleting stack allocated objecs. Probably you're hanging in while (!viewer.wasStopped ()) loop.

[jsulm]

@surajj4837 Also, does pcl::visualization::CloudViewer allocate the actual dialog on the heap?

[JonB]

@surajj4837
For one thing, because of your

pcl::visualization::CloudViewer viewer("Cloud Viewer");

local variable this will be automatically destructed on reaching the end of function's } scope. You shouldn't call the destructor explicitly, even if that was OK I imagine it would cause double-destruction on exiting the method....

[surajj4837]

@jsulm The CloudViewer constructor definition says it creates the object on heap.

[surajj4837]

@JonB https://www.geeksforgeeks.org/possible-call-constructor-destructor-explicitly/

[Christian Ehrlicher]

@surajj4837 You must not call a dtor for an object when you created it on the stack as you did - no matter if you call it in an unusual way like you did or with the correct c++ way by calling delete. C++ basics.

[JonB]

@surajj4837

@JonB https://www.geeksforgeeks.org/possible-call-constructor-destructor-explicitly/

Explicit call to destructor is only necessary when object is placed at particular location in memory by using placement new.

Do you have any evidence this is the case for you?

[jsulm]

@surajj4837 said in Mainwindow closes when I close PCL window.:

The CloudViewer constructor definition says it creates the object on heap

Please show its code. viewer itself is allocated on the stack as you can clearly see from your code...

[surajj4837]

@Christian-Ehrlicher Okay

[surajj4837]

@JonB No.

[surajj4837]

@jsulm Official source code. Line #266.

[jsulm]

@surajj4837 said in Mainwindow closes when I close PCL window.:

Line #266.

What is in that line?

[Christian Ehrlicher]

@surajj4837 said in Mainwindow closes when I close PCL window.:

@jsulm Official source code. Line #266.

There the object itself creates a new object on the heap. Don't know what this should have to do with your object which you create on the stack though.

[jsulm]

@surajj4837 This does not change anything! viewer is allocated on the stack. Its constructor allocates something on the heap but that is deleted in the destructor. But you do not have to call destructor for objects allocated on the stack as it is called when the object is destroyed (if it leaves its scope). I suggest you learn C++ basics (memory management).

[jsulm]

@surajj4837 Actually there seems to be a bug:

00270 pcl::visualization::CloudViewer::~CloudViewer ()
00271 {
00272   impl_->quit_ = true;
00273   impl_->viewer_thread_.join();
00274 }
00275 

Destructor does not delete impl!
It should be

pcl::visualization::CloudViewer::~CloudViewer ()
{
   impl_->quit_ = true;
   impl_->viewer_thread_.join();
   delete impl;
}