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reading file line by line crashes

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qt 4.8qtextstreamreadline
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  • M mourad_bilog

    First, Thanks for reply.

    @jsulm it's a memory crash. Below the error occured :

    Exception de première chance à 0x0fcbd5be (msvcr80d.dll) dans TheriaqueUpdater.exe : 0xC0000005: Violation d'accès lors de l'écriture à l'emplacement 0x2804e000.
    Exception non gérée à 0x0fcbd5be (msvcr80d.dll) dans TheriaqueUpdater.exe : 0xC0000005: Violation d'accès lors de l'écriture à l'emplacement 0x2804e000.
    

    @J-Hilk the crash occus on in.readLine. The recod data has 6 entries and it's shown evey time.
    I've commented the eventLoop but the application still crashes.

    Note that line data lengths can be around 1 milion carachtars.

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #5

    @mourad_bilog said in reading file line by line crashes:

    Note that line data lengths can be around 1 milion carachtars

    How long is the line you're reading when the app is crashing?

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

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    • M mourad_bilog

      First, Thanks for reply.

      @jsulm it's a memory crash. Below the error occured :

      Exception de première chance à 0x0fcbd5be (msvcr80d.dll) dans TheriaqueUpdater.exe : 0xC0000005: Violation d'accès lors de l'écriture à l'emplacement 0x2804e000.
      Exception non gérée à 0x0fcbd5be (msvcr80d.dll) dans TheriaqueUpdater.exe : 0xC0000005: Violation d'accès lors de l'écriture à l'emplacement 0x2804e000.
      

      @J-Hilk the crash occus on in.readLine. The recod data has 6 entries and it's shown evey time.
      I've commented the eventLoop but the application still crashes.

      Note that line data lengths can be around 1 milion carachtars.

      J.HilkJ Offline
      J.HilkJ Offline
      J.Hilk
      Moderators
      wrote on last edited by
      #6

      @mourad_bilog said in reading file line by line crashes:

      @J-Hilk the crash occus on in.readLine. The recod data has 6 entries and it's shown evey time.

      do not base this solely on faith:

      if(record_data.size()> 3)
      qDebug() << "Fin lecture d'une ligne n°" << QString::number(++nb_cmd) << record_data[3] << QTime::currentTime().toString("hh:mm") << endl ;
       else
       qDebug() << "would have crashed";
      

      Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


      Q: What's that?
      A: It's blue light.
      Q: What does it do?
      A: It turns blue.

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      • M Offline
        M Offline
        mourad_bilog
        wrote on last edited by
        #7

        @jsulm said in reading file line by line crashes:

        How long is the line you're reading when the app is crashing?

        About 1 200 000 charactars.

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        • M Offline
          M Offline
          mourad_bilog
          wrote on last edited by
          #8

          @J-Hilk
          I've commented that line but the same occurs.

          J.HilkJ 1 Reply Last reply
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          • M mourad_bilog

            @J-Hilk
            I've commented that line but the same occurs.

            J.HilkJ Offline
            J.HilkJ Offline
            J.Hilk
            Moderators
            wrote on last edited by
            #9

            @mourad_bilog alight thanks thumbs up

            question , is this Qt4?
            and is this a multi threaded project, and is do you read and write to that file from different places ?


            Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


            Q: What's that?
            A: It's blue light.
            Q: What does it do?
            A: It turns blue.

            M 1 Reply Last reply
            0
            • J.HilkJ J.Hilk

              @mourad_bilog alight thanks thumbs up

              question , is this Qt4?
              and is this a multi threaded project, and is do you read and write to that file from different places ?

              M Offline
              M Offline
              mourad_bilog
              wrote on last edited by
              #10

              @J.Hilk
              question , is this Qt4? yes. but the program runs correctly for some years.

              and is this a multi threaded project, : No, it's one thread.

              and is do you read and write to that file from different places : No, I just read from that file. I just open it in "ReadOnly" mode.

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

                I've read in a post how has similar problem that he has solved the problem using file.readLine no QTextStream.readLine(). What is the difference between the 2 functions ?

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                • Christian EhrlicherC Offline
                  Christian EhrlicherC Offline
                  Christian Ehrlicher
                  Lifetime Qt Champion
                  wrote on last edited by
                  #12

                  @mourad_bilog said in reading file line by line crashes:

                  1 200 000

                  really one line?

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

                    @Christian-Ehrlicher there's many lines witch everyone exceed 1 milion charactars.
                    Is this a problem ? That can exceed what QTextStream buffer contains ?

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                    • Christian EhrlicherC Offline
                      Christian EhrlicherC Offline
                      Christian Ehrlicher
                      Lifetime Qt Champion
                      wrote on last edited by
                      #14

                      At least I would consider this - it's a 2.4MB huge QString, should be ok but who knows. I would simply try QFile::readLine(), split the QByteArray and convert to QString as late as possible (if needed at all)

                      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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                      • M Offline
                        M Offline
                        mourad_bilog
                        wrote on last edited by
                        #15

                        Checking Windows events journal, it indicates that msvcr causes this crash, that's true ?

                        Nom de l’application défaillante Updater.exe, version : 2.7.4.0, horodatage : 0x5a018f88
                        Nom du module défaillant : MSVCR80.dll, version : 8.0.50727.9445, horodatage : 0x5a7bc74c
                        Code d’exception : 0xc0000005
                        Décalage d’erreur : 0x0001508e
                        ID du processus défaillant : 0x19a0
                        Heure de début de l’application défaillante : 0x01d4d8a5bb99dd52
                        Chemin d’accès du module défaillant: C:\WINDOWS\WinSxS\x86_microsoft.vc80.crt_1fc8b3b9a1e18e3b_8.0.50727.9445_none_d08c58b4442ba54f\MSVCR80.dll
                        ID de rapport : 6c470b7e-a3b2-4584-b404-3d7957545ead
                        Nom complet du package défaillant : 
                        ID de l’application relative au package défaillant : 
                        

                        I've re-installed Visual redistribuable 2005 but the problem persists. Note that I dont found msvcr80 in the system32 not like other versions msvcr71, msvcr10, etc.

                        Does this the problem ?

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

                          Hi,

                          Did you monitor your application RAM usage ?

                          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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                          • M Offline
                            M Offline
                            mourad_bilog
                            wrote on last edited by
                            #17

                            Finally I changed reading mode to read directly from the data file. It's most faster and just I was care to encode data when reading to keep special charcatars.

                            Thanks all for your ideas

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