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Mainwindow closes when I close PCL window.

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  • 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 Online
          Christian EhrlicherC Online
          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

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          • 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
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            • 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

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                • 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
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                    • 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
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                      • S surajj4837

                        @jsulm Official source code. Line #266.

                        Christian EhrlicherC Online
                        Christian EhrlicherC Online
                        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

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                        • 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
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                          • 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
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                            • 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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