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QThread and Error Access violation

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  • ? Offline
    ? Offline
    A Former User
    wrote on last edited by
    #3

    [quote author="SGaist" date="1407411703"]Hi,

    Are you trying to call MainWindow::_send directly from MyThread::run ?[/quote]

    hi SGaist how are you ?
    Thanks for your reply..

    By MainWindow::_send(); i get this error :

    @

    error: cannot call member function 'void MainWindow::_send()' without object
    MainWindow::_send();
    ^
    @

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #4

      You can't call a function from another class.

      Also, you have a signature mismatch between your header and implementation.

      What exactly are you trying to achieve ?

      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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      • ? Offline
        ? Offline
        A Former User
        wrote on last edited by
        #5

        [quote author="SGaist" date="1407412316"]You can't call a function from another class.

        Also, you have a signature mismatch between your header and implementation.

        What exactly are you trying to achieve ?
        [/quote]

        Where is my mismatch can u show me?
        I want to change my tabWidget status from disable to enable after Thread processing...

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #6

          @
          namespace Ui {
          class MainWindow;
          }

          class MainWindow : public QMainWindow
          {
          Q_OBJECT

          public:
          explicit MainWindow(QWidget *parent = 0);
          ~MainWindow();
          public:
          void _send(QString _title, QString _message); << here
          }; @

          @
          void MyThread::run()
          {
          //Run my function
          _send(); << there
          }
          @

          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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          • ? Offline
            ? Offline
            A Former User
            wrote on last edited by
            #7

            [quote author="SGaist" date="1407442699"]@
            namespace Ui {
            class MainWindow;
            }

            class MainWindow : public QMainWindow
            {
            Q_OBJECT

            public:
            explicit MainWindow(QWidget *parent = 0);
            ~MainWindow();
            public:
            void _send(QString _title, QString _message); << here
            }; @

            @
            void MyThread::run()
            {
            //Run my function
            _send(); << there
            }
            @

            [/quote]

            Hi again...

            I Chaged to

            @
            public:
            void _send();
            @

            and

            @
            void MainWindow::_send()

            {

            ui->tabWidget->setDisabled(false);

            };
            @

            and

            @
            void MyThread::run()
            {
            //Run my function
            //MainWindow::_send();

            MainWindow *II;
                II->_send();
            

            }
            @

            but not working !
            Error :

            @
            QObject::connect: No such slot MainWindow::_send() in ..\untitled15\mainwindow.cpp:40
            QObject::connect: (receiver name: 'MainWindow')
            @

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            • ? Offline
              ? Offline
              A Former User
              wrote on last edited by
              #8

              try to change "public" into "public slots" before your send function.

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              • ? Offline
                ? Offline
                A Former User
                wrote on last edited by
                #9

                [quote author="msue" date="1407481533"]try to change "public" into "public slots" before your send function.[/quote]

                Unfortunately ...
                The program has unexpectedly finished.
                ..\untitled15.exe crashed

                :(

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #10

                  That's normal, MainWindow *ll is uninitialized.

                  Anyway, you should not access MainWindow from your thread, just emit the signal you connected earlier.

                  Also it's seems you are new to C++, I'd recommend getting a good book about it

                  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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                  • ? Offline
                    ? Offline
                    A Former User
                    wrote on last edited by
                    #11

                    [quote author="SGaist" date="1407483129"]That's normal, MainWindow *ll is uninitialized.

                    Anyway, you should not access MainWindow from your thread, just emit the signal you connected earlier.

                    Also it's seems you are new to C++, I'd recommend getting a good book about it[/quote]

                    Can you show me a good document or book about this question ?!
                    I mean how to update GUI in Thread process.

                    Thank you.

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #12

                      Qt's own documentation and examples e.g. the Mandelbrot example

                      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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                      • ? Offline
                        ? Offline
                        A Former User
                        wrote on last edited by
                        #13

                        [quote author="SGaist" date="1407484062"]Qt's own documentation and examples e.g. the Mandelbrot example[/quote]

                        Thank you for your helping... i try to read it :)

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