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Mainwindow closes when I close PCL window.

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  • S 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();
        
    }
    
    JonBJ Offline
    JonBJ Offline
    JonB
    wrote on last edited by
    #10

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

    viewer.~CloudViewer();

    Ummm??

    1 Reply Last reply
    0
    • S 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();
          
      }
      
      jsulmJ Offline
      jsulmJ Offline
      jsulm
      Lifetime Qt Champion
      wrote on last edited by
      #11

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

      https://forum.qt.io/topic/113070/qt-code-of-conduct

      S 1 Reply Last reply
      1
      • jsulmJ jsulm

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

        S Offline
        S Offline
        surajj4837
        wrote on last edited by
        #12

        @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.

        jsulmJ 1 Reply Last reply
        0
        • JonBJ JonB

          @surajj4837
          Yes.

          So what does line #55 of your MainWindow::on_pushButton_clicked do? Looks like there is a clue about destructing a CloudViewer?

          S Offline
          S Offline
          surajj4837
          wrote on last edited by
          #13

          @JonB

          This viewer declaration is in line #55:

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

          When destructor is called the execution jumps to that line.

          jsulmJ JonBJ 2 Replies Last reply
          0
          • S 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.

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #14

            @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.

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            1 Reply Last reply
            1
            • S 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.

              jsulmJ Offline
              jsulmJ Offline
              jsulm
              Lifetime Qt Champion
              wrote on last edited by
              #15

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

              https://forum.qt.io/topic/113070/qt-code-of-conduct

              S 1 Reply Last reply
              0
              • S 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.

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by
                #16

                @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....

                S 1 Reply Last reply
                1
                • jsulmJ jsulm

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

                  S Offline
                  S Offline
                  surajj4837
                  wrote on last edited by
                  #17

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

                  jsulmJ 1 Reply Last reply
                  0
                  • JonBJ 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....

                    S Offline
                    S Offline
                    surajj4837
                    wrote on last edited by
                    #18

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

                    Christian EhrlicherC JonBJ 2 Replies Last reply
                    0
                    • S surajj4837

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

                      Christian EhrlicherC Offline
                      Christian EhrlicherC Offline
                      Christian Ehrlicher
                      Lifetime Qt Champion
                      wrote on last edited by Christian Ehrlicher
                      #19

                      @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.

                      Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                      Visit the Qt Academy at https://academy.qt.io/catalog

                      S 1 Reply Last reply
                      1
                      • S surajj4837

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

                        JonBJ Offline
                        JonBJ Offline
                        JonB
                        wrote on last edited by JonB
                        #20

                        @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?

                        S 1 Reply Last reply
                        0
                        • S surajj4837

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

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #21

                          @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...

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

                          S 1 Reply Last reply
                          0
                          • Christian EhrlicherC 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.

                            S Offline
                            S Offline
                            surajj4837
                            wrote on last edited by
                            #22

                            @Christian-Ehrlicher Okay

                            1 Reply Last reply
                            0
                            • JonBJ 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?

                              S Offline
                              S Offline
                              surajj4837
                              wrote on last edited by
                              #23

                              @JonB No.

                              1 Reply Last reply
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                              • jsulmJ 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...

                                S Offline
                                S Offline
                                surajj4837
                                wrote on last edited by
                                #24

                                @jsulm Official source code. Line #266.

                                jsulmJ Christian EhrlicherC 4 Replies Last reply
                                0
                                • S surajj4837

                                  @jsulm Official source code. Line #266.

                                  jsulmJ Offline
                                  jsulmJ Offline
                                  jsulm
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #25

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

                                  Line #266.

                                  What is in that line?

                                  https://forum.qt.io/topic/113070/qt-code-of-conduct

                                  1 Reply Last reply
                                  0
                                  • S surajj4837

                                    @jsulm Official source code. Line #266.

                                    Christian EhrlicherC Offline
                                    Christian EhrlicherC Offline
                                    Christian Ehrlicher
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #26

                                    @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.

                                    Qt Online Installer direct download: https://download.qt.io/official_releases/online_installers/
                                    Visit the Qt Academy at https://academy.qt.io/catalog

                                    1 Reply Last reply
                                    0
                                    • S surajj4837

                                      @jsulm Official source code. Line #266.

                                      jsulmJ Offline
                                      jsulmJ Offline
                                      jsulm
                                      Lifetime Qt Champion
                                      wrote on last edited by jsulm
                                      #27

                                      @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).

                                      https://forum.qt.io/topic/113070/qt-code-of-conduct

                                      S 1 Reply Last reply
                                      1
                                      • S surajj4837

                                        @jsulm Official source code. Line #266.

                                        jsulmJ Offline
                                        jsulmJ Offline
                                        jsulm
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #28

                                        @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;
                                        }
                                        

                                        https://forum.qt.io/topic/113070/qt-code-of-conduct

                                        1 Reply Last reply
                                        0
                                        • jsulmJ 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).

                                          S Offline
                                          S Offline
                                          surajj4837
                                          wrote on last edited by
                                          #29

                                          @jsulm Sure, I will do that.

                                          1 Reply Last reply
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