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Segmentation fault on dummy app

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imx6yocto
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  • R raven-worx
    16 Jun 2016, 11:01

    @VincentB
    did you compile Qt yourself?
    Please also post the stack trace of the crash

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    VincentB
    wrote on 16 Jun 2016, 11:28 last edited by
    #5

    @raven-worx ,

    Qt has been compiled by yocto.

    What steps I have to follow to have a stack trace ?

    R 1 Reply Last reply 17 Jun 2016, 05:46
    0
    • M Offline
      M Offline
      micland
      wrote on 16 Jun 2016, 11:30 last edited by
      #6

      @VincentB
      As I see you use QApplication which is designed for GUI apps. I don't think that this is the reason but can you try to replace QApplication with QCoreApplication and repeat the test?

      Footnote: I can't reproduce the error with Qt 5.5 on Ubuntu (no crash).

      V 1 Reply Last reply 16 Jun 2016, 12:09
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      • M micland
        16 Jun 2016, 11:30

        @VincentB
        As I see you use QApplication which is designed for GUI apps. I don't think that this is the reason but can you try to replace QApplication with QCoreApplication and repeat the test?

        Footnote: I can't reproduce the error with Qt 5.5 on Ubuntu (no crash).

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        VincentB
        wrote on 16 Jun 2016, 12:09 last edited by
        #7

        @micland ,

        With QCoreApplication, there is no problem. What could we conclude ?

        M K 2 Replies Last reply 16 Jun 2016, 12:43
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        • V VincentB
          16 Jun 2016, 12:09

          @micland ,

          With QCoreApplication, there is no problem. What could we conclude ?

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          M Offline
          micland
          wrote on 16 Jun 2016, 12:43 last edited by
          #8

          @VincentB said:

          With QCoreApplication, there is no problem. What could we conclude ?

          Fine - we found a solution :) But I have no idea what the problem is. QApplication inherits QGuiApplication which inherits QCoreApplication. In my opinion the child classes just add additional GUI related functionality but should not have different behaviour (and shall not have following the Liskov substitution principle).
          The documentation only says that QCoreApplication should be used for non-GUI applications because it has no dependencies to QWidgets. But there is no note that you have to use only QCoreApplication.
          Perhaps someone else here knows more about the internas of the three classes?

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          • V VincentB
            16 Jun 2016, 12:09

            @micland ,

            With QCoreApplication, there is no problem. What could we conclude ?

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            kshegunov
            Moderators
            wrote on 16 Jun 2016, 13:52 last edited by
            #9

            @VincentB @micland
            Well,
            QCoreApplication does almost nothing - it starts an event loop, while QApplication is fat and heavy and loads plugins and platform integrations and widgety things, so it may simply be a bug. But in any case @raven-worx's request is relevant, you should obtain a stack trace from the crash (how depends on the IDE and its setup).

            Kind regards.

            Read and abide by the Qt Code of Conduct

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              VincentB
              wrote on 16 Jun 2016, 15:58 last edited by VincentB
              #10

              Ok,

              I''ve done this test cause on my main gui application I've got the same problem. Now, I'll search how to get a good stack trace to poste here (Unless you can advice me on how to do that).

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              • V VincentB
                16 Jun 2016, 11:28

                @raven-worx ,

                Qt has been compiled by yocto.

                What steps I have to follow to have a stack trace ?

                R Offline
                R Offline
                raven-worx
                Moderators
                wrote on 17 Jun 2016, 05:46 last edited by
                #11

                @VincentB
                from where do you have the console output? From your IDE?
                If so there should also be a window which shows the stack trace at the time of the crash.

                --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
                If you have a question please use the forum so others can benefit from the solution in the future

                V 1 Reply Last reply 17 Jun 2016, 12:51
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                • R raven-worx
                  17 Jun 2016, 05:46

                  @VincentB
                  from where do you have the console output? From your IDE?
                  If so there should also be a window which shows the stack trace at the time of the crash.

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                  VincentB
                  wrote on 17 Jun 2016, 12:51 last edited by
                  #12

                  @raven-worx ,

                  Hi, ok, I'll check this

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                    VincentB
                    wrote on 17 Jun 2016, 13:14 last edited by
                    #13

                    Sorry but I'm not sure to find where to find this stack window .. (I'm using qtcreator 3.6.0)

                    R 1 Reply Last reply 20 Jun 2016, 06:09
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                    • V VincentB
                      17 Jun 2016, 13:14

                      Sorry but I'm not sure to find where to find this stack window .. (I'm using qtcreator 3.6.0)

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                      R Offline
                      raven-worx
                      Moderators
                      wrote on 20 Jun 2016, 06:09 last edited by raven-worx
                      #14

                      @VincentB said:

                      Sorry but I'm not sure to find where to find this stack window .. (I'm using qtcreator 3.6.0)

                      see this.

                      --- SUPPORT REQUESTS VIA CHAT WILL BE IGNORED ---
                      If you have a question please use the forum so others can benefit from the solution in the future

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