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Correct syntax to register object reference using qRegisterMetaType?

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  • SPlattenS SPlatten

    @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. I'm not experience any other problems, crashes or bugs.

    JonBJ Online
    JonBJ Online
    JonB
    wrote on last edited by
    #14

    @SPlatten
    The signal argument type is "OK", insofar as it would work OK with non-cross-thread direct connection connect()s. But the problem is that you are trying to use it when you need a queued connection. That is why you get the error message on the QObject::connect statement.

    SPlattenS 1 Reply Last reply
    1
    • JonBJ JonB

      @SPlatten
      The signal argument type is "OK", insofar as it would work OK with non-cross-thread direct connection connect()s. But the problem is that you are trying to use it when you need a queued connection. That is why you get the error message on the QObject::connect statement.

      SPlattenS Offline
      SPlattenS Offline
      SPlatten
      wrote on last edited by
      #15

      @JonB , thank you, I'll take a look.

      Kind Regards,
      Sy

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      • SPlattenS SPlatten

        @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. I'm not experience any other problems, crashes or bugs.

        SGaistS Offline
        SGaistS Offline
        SGaist
        Lifetime Qt Champion
        wrote on last edited by
        #16

        @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

        @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. I'm not experience any other problems, crashes or bugs.

        For the slots as well ?

        Interested in AI ? www.idiap.ch
        Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

        SPlattenS 1 Reply Last reply
        2
        • SGaistS SGaist

          @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

          @kshegunov , I am using const QJsonObject& for my signal arguments, these are working, the only thing that is displayed in the Application Output is the message I've raised. I'm not experience any other problems, crashes or bugs.

          For the slots as well ?

          SPlattenS Offline
          SPlattenS Offline
          SPlatten
          wrote on last edited by
          #17

          @SGaist Of course.

          Kind Regards,
          Sy

          1 Reply Last reply
          0
          • SPlattenS Offline
            SPlattenS Offline
            SPlatten
            wrote on last edited by
            #18

            Ok, I've now got rid of the warning, by going through all the QObject::connect calls and only using Qt::DirectionConnection where the signal and slot pointers are the same.

            Kind Regards,
            Sy

            JonBJ 1 Reply Last reply
            0
            • SPlattenS SPlatten

              Ok, I've now got rid of the warning, by going through all the QObject::connect calls and only using Qt::DirectionConnection where the signal and slot pointers are the same.

              JonBJ Online
              JonBJ Online
              JonB
              wrote on last edited by
              #19

              @SPlatten
              A lot of your questions are about threads. Are your connect()s' senders/receivers never in separate threads?

              SPlattenS 1 Reply Last reply
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              • JonBJ JonB

                @SPlatten
                A lot of your questions are about threads. Are your connect()s' senders/receivers never in separate threads?

                SPlattenS Offline
                SPlattenS Offline
                SPlatten
                wrote on last edited by
                #20

                @JonB , not for the ones where I've used Qt::DirectConnection

                Kind Regards,
                Sy

                1 Reply Last reply
                1
                • Christian EhrlicherC Offline
                  Christian EhrlicherC Offline
                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on last edited by
                  #21

                  @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                  not for the ones where I've used Qt::DirectConnection

                  Then it's useless since then Qt::AutoConnection evaluates to Qt::DirectConnection. Specifying a connection type is not needed in most of the cases.

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

                  SPlattenS 1 Reply Last reply
                  0
                  • Christian EhrlicherC Christian Ehrlicher

                    @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                    not for the ones where I've used Qt::DirectConnection

                    Then it's useless since then Qt::AutoConnection evaluates to Qt::DirectConnection. Specifying a connection type is not needed in most of the cases.

                    SPlattenS Offline
                    SPlattenS Offline
                    SPlatten
                    wrote on last edited by
                    #22

                    @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                    Kind Regards,
                    Sy

                    SGaistS Christian EhrlicherC kshegunovK 3 Replies Last reply
                    0
                    • SPlattenS SPlatten

                      @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                      SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #23

                      @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                      @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                      For that a minimal compilable example would be needed.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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                      • SPlattenS SPlatten

                        @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                        Christian EhrlicherC Offline
                        Christian EhrlicherC Offline
                        Christian Ehrlicher
                        Lifetime Qt Champion
                        wrote on last edited by
                        #24

                        @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                        so perhaps this is something that needs looking at?

                        This means that there is a thread context switch somewhere even you tell us it isn't.

                        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
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                        • SPlattenS SPlatten

                          @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                          kshegunovK Offline
                          kshegunovK Offline
                          kshegunov
                          Moderators
                          wrote on last edited by
                          #25

                          @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                          @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                          Run with QT_FATAL_WARNINGS=1 as an environment variable and extract the stack trace, then you will have leveraged your debugger to show you exactly where you're passing a reference between threads.

                          Read and abide by the Qt Code of Conduct

                          SPlattenS 1 Reply Last reply
                          2
                          • kshegunovK kshegunov

                            @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                            @Christian-Ehrlicher , Well that's the only change I'm implemented and now there is no message, so perhaps this is something that needs looking at?

                            Run with QT_FATAL_WARNINGS=1 as an environment variable and extract the stack trace, then you will have leveraged your debugger to show you exactly where you're passing a reference between threads.

                            SPlattenS Offline
                            SPlattenS Offline
                            SPlatten
                            wrote on last edited by
                            #26

                            @kshegunov said in Correct syntax to register object reference using qRegisterMetaType?:

                            QT_FATAL_WARNINGS=1

                            I've opened both .pro files and added that line, then cleaned and rebuilt, the applications have been running for several minutes, nothing to report, no issues.

                            Kind Regards,
                            Sy

                            1 Reply Last reply
                            0
                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #27

                              It's an environnement variable, not a define.

                              You have to set it in the Run tab of the Project panel.

                              Interested in AI ? www.idiap.ch
                              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                              SPlattenS 1 Reply Last reply
                              1
                              • SGaistS SGaist

                                It's an environnement variable, not a define.

                                You have to set it in the Run tab of the Project panel.

                                SPlattenS Offline
                                SPlattenS Offline
                                SPlatten
                                wrote on last edited by
                                #28

                                @SGaist , Yes, just googled it and then added as environment variable:

                                export QT_FATAL_WARNINGS=1
                                

                                Then restarted, same, not seeing anything additional.

                                Kind Regards,
                                Sy

                                1 Reply Last reply
                                0
                                • SGaistS Offline
                                  SGaistS Offline
                                  SGaist
                                  Lifetime Qt Champion
                                  wrote on last edited by
                                  #29

                                  Restarted what ?
                                  How are you currently running your application ?

                                  Interested in AI ? www.idiap.ch
                                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                  SPlattenS 1 Reply Last reply
                                  1
                                  • SGaistS SGaist

                                    Restarted what ?
                                    How are you currently running your application ?

                                    SPlattenS Offline
                                    SPlattenS Offline
                                    SPlatten
                                    wrote on last edited by
                                    #30

                                    @SGaist , I launch the processes with Qt Creator in debug mode, using two separate instances of Qt Creator.

                                    Kind Regards,
                                    Sy

                                    1 Reply Last reply
                                    0
                                    • SGaistS Offline
                                      SGaistS Offline
                                      SGaist
                                      Lifetime Qt Champion
                                      wrote on last edited by SGaist
                                      #31

                                      Did you check the environment variables in the Run part of the Project Panel to ensure it's properly set ?

                                      Interested in AI ? www.idiap.ch
                                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                                      SPlattenS 1 Reply Last reply
                                      1
                                      • SGaistS SGaist

                                        Did you check the environment variables in the Run part of the Project Panel to ensure it's properly set ?

                                        SPlattenS Offline
                                        SPlattenS Offline
                                        SPlatten
                                        wrote on last edited by
                                        #32

                                        @SGaist , I checked in a terminal, I don't know how or where to "Run part of the Project Panel" ?

                                        Kind Regards,
                                        Sy

                                        jsulmJ 1 Reply Last reply
                                        0
                                        • SPlattenS SPlatten

                                          @SGaist , I checked in a terminal, I don't know how or where to "Run part of the Project Panel" ?

                                          jsulmJ Offline
                                          jsulmJ Offline
                                          jsulm
                                          Lifetime Qt Champion
                                          wrote on last edited by jsulm
                                          #33

                                          @SPlatten said in Correct syntax to register object reference using qRegisterMetaType?:

                                          I don't know how or where to "Run part of the Project Panel" ?

                                          Easy to find actually.
                                          Left pane: Projects -> Build & Run -> Run...

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

                                          SPlattenS 1 Reply Last reply
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