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How to correctly unload QApplication in a DLL?

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  • M Offline
    M Offline
    maisoui
    wrote on last edited by
    #11

    Yes, qApp can be NULL (from documentation: Returns a pointer to the application's QCoreApplication (or QApplication) instance. If no instance has been allocated, null is returned). But don't focus on that, If I change the code like this, problem is the same.
    @int argc = 0;
    myApplication = new QApplication(argc, NULL);

    ...

    delete myApplication;@

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    • A Offline
      A Offline
      AlterX
      wrote on last edited by
      #12

      I don't think this is your problem...you are just setting a normal variable (QVariant) with another variable (MyObject)...problem is on qApp stuff.
      Can you check if second time a new QApplication is created again?

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      • M Offline
        M Offline
        maisoui
        wrote on last edited by
        #13

        Checked. The second time a new QApplication is created too.

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        • sierdzioS Offline
          sierdzioS Offline
          sierdzio
          Moderators
          wrote on last edited by
          #14

          I think you would get better answers on the interest mailing list. People fluent in QtCore code are likely to know the cause of your problem.

          (Z(:^

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          • A Offline
            A Offline
            AlterX
            wrote on last edited by
            #15

            Anyway scenario is very complex since you are using a static object in process with another application (autocad) and managing a QApplication using qApp that can have different scope and logic behind.
            Can you tell me why are you using QApplication and if you remove those instructions if it is working

            Qt Ambassador
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            Free Real-time network platform sdk: https://github.com/AlterX76/Solomon

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            • M Offline
              M Offline
              maisoui
              wrote on last edited by
              #16

              As with any Qt application, I need to create a valid QApplication. I'm surprised by your question.

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              • A Offline
                A Offline
                AlterX
                wrote on last edited by
                #17

                I don't understand...you are creating a plugin for Autocad if you don't need gui why are you using Qt?
                and again I don't think this is the correct approch to check qApp and create an anonymous QApplication without an explicit reference

                Qt Ambassador
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                Free Real-time network platform sdk: https://github.com/AlterX76/Solomon

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                • sierdzioS Offline
                  sierdzioS Offline
                  sierdzio
                  Moderators
                  wrote on last edited by
                  #18

                  AlterX QObject class requires a valid QCoreApplication instance to work properly.

                  (Z(:^

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                  • M Offline
                    M Offline
                    maisoui
                    wrote on last edited by
                    #19

                    Yes, and I need GUI. I do a little condensed code just to reproduce the issue. Of course, this is not my whole application. It's just a "debug" example.

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                    • A Offline
                      A Offline
                      AlterX
                      wrote on last edited by
                      #20

                      Ok, so due to this problem can be related to in process plugin, it is very hard to help you since we don't know how to reproduce this on our own. Maybe you can try to not unload the entire plugin and reload it, and have a only one instance of QApplication created when you load plugin? Can you do this?

                      Qt Ambassador
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                      Free Real-time network platform sdk: https://github.com/AlterX76/Solomon

                      https://codereview.qt-project.org/...

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                      • A Offline
                        A Offline
                        AlterX
                        wrote on last edited by
                        #21

                        [quote author="sierdzio" date="1417515370"]AlterX QObject class requires a valid QCoreApplication instance to work properly.[/quote]

                        Yes I know of course, but since he spoke about just an example I was thinking that original code was not using Qt and that this was just a curious question for him

                        Qt Ambassador
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