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problem using QSerialPort

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  • jsulmJ jsulm

    @mzimmers Is there a reason why you're using a thread? QSerialPort has an asynchronous API and there is usually no need to use threads for that.

    mzimmersM Offline
    mzimmersM Offline
    mzimmers
    wrote on last edited by
    #8

    @jsulm I'm not using a thread exclusively for the serial port work; my worker thread essentially does all my non-UI stuff(encoding/decoding messages, etc.)
    @kshegunov sorry; I was engaging in a bit of shorthand. m_serialPort is a member variable of SerialPort. The connect is correct, though.
    @J-Hilk I'm currently using (non-static) 5.12.5.

    Last night it occurred to me that long ago, I'd come across a problem with transferring objects to new threads, in which some sub-objects don't get transferred properly.

    I might try Dorfman's idea, though I'd prefer not to have to do that.

    Thanks...

    J.HilkJ 1 Reply Last reply
    1
    • mzimmersM mzimmers

      @jsulm I'm not using a thread exclusively for the serial port work; my worker thread essentially does all my non-UI stuff(encoding/decoding messages, etc.)
      @kshegunov sorry; I was engaging in a bit of shorthand. m_serialPort is a member variable of SerialPort. The connect is correct, though.
      @J-Hilk I'm currently using (non-static) 5.12.5.

      Last night it occurred to me that long ago, I'd come across a problem with transferring objects to new threads, in which some sub-objects don't get transferred properly.

      I might try Dorfman's idea, though I'd prefer not to have to do that.

      Thanks...

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

      @mzimmers said in problem using QSerialPort:

      @J-Hilk I'm currently using (non-static) 5.12.5.

      And there is your problem
      https://bugreports.qt.io/browse/QTBUG-78086

      please update


      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.

      mzimmersM 1 Reply Last reply
      3
      • J.HilkJ J.Hilk

        @mzimmers said in problem using QSerialPort:

        @J-Hilk I'm currently using (non-static) 5.12.5.

        And there is your problem
        https://bugreports.qt.io/browse/QTBUG-78086

        please update

        mzimmersM Offline
        mzimmersM Offline
        mzimmers
        wrote on last edited by
        #10

        @J-Hilk bang! Good eye. Thanks for catching that. I'll update immediately.

        KroMignonK 1 Reply Last reply
        2
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #11

          Hi,

          IIRC, your QSerialPort object won't get moved if your don't parent it.

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

          mzimmersM 1 Reply Last reply
          1
          • mzimmersM mzimmers

            @J-Hilk bang! Good eye. Thanks for catching that. I'll update immediately.

            KroMignonK Offline
            KroMignonK Offline
            KroMignon
            wrote on last edited by KroMignon
            #12

            @mzimmers said in problem using QSerialPort:

            Good eye. Thanks for catching that. I'll update immediately.

            Any way, your initialization seems not correct to me:

            SerialPort::SerialPort(QObject *parent) : QObject (parent)
            {
                QSerialPort m_serialPort;
                connect(&m_serialPort, &QSerialPort::readyRead, this, &SerialPort::readSerial);
            ...
            }
            

            should be, I think:

            SerialPort::SerialPort(QObject *parent)
                 : QObject (parent)
                 , m_serialPort(new QSerialPort(this))
            {
                connect(m_serialPort, &QSerialPort::readyRead, this, &SerialPort::readSerial);
            ...
            }
            

            It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

            1 Reply Last reply
            1
            • SGaistS SGaist

              Hi,

              IIRC, your QSerialPort object won't get moved if your don't parent it.

              mzimmersM Offline
              mzimmersM Offline
              mzimmers
              wrote on last edited by mzimmers
              #13

              @SGaist ah yes, that's what it was. Thanks for refreshing my memory.

              Edit:

              Which member variables does this apply to? For example, I also have a member QByteArray; does that need to be parented too?

              Thanks...

              KroMignonK 1 Reply Last reply
              0
              • mzimmersM mzimmers

                @SGaist ah yes, that's what it was. Thanks for refreshing my memory.

                Edit:

                Which member variables does this apply to? For example, I also have a member QByteArray; does that need to be parented too?

                Thanks...

                KroMignonK Offline
                KroMignonK Offline
                KroMignon
                wrote on last edited by
                #14

                @mzimmers said in problem using QSerialPort:

                Which member variables does this apply to?

                Each member which base class is QObject.

                It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth. (Sherlock Holmes)

                mzimmersM 1 Reply Last reply
                2
                • KroMignonK KroMignon

                  @mzimmers said in problem using QSerialPort:

                  Which member variables does this apply to?

                  Each member which base class is QObject.

                  mzimmersM Offline
                  mzimmersM Offline
                  mzimmers
                  wrote on last edited by mzimmers
                  #15

                  @KroMignon thanks...so a QByteArray object wouldn't be affected then.

                  It looks like the mechanics of updating have changed since I last used them. Is there a pre-built 5.14 for Windows available somewhere on github? EDIT: looks like the answer is "no;" I guess everyone builds their own now. Given my recent troubles trying to build a static Qt, I hope the directions in the 5.14 README are accurate.

                  I'm going to mark this solved, in anticipation that when I get a new Qt built, it'll work. Thanks for everyone's input on this.

                  1 Reply Last reply
                  0
                  • SGaistS Offline
                    SGaistS Offline
                    SGaist
                    Lifetime Qt Champion
                    wrote on last edited by
                    #16

                    You need now to use your Qt account to access the pre-built binaries (the same you use to post here)

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

                    mzimmersM 1 Reply Last reply
                    0
                    • SGaistS SGaist

                      You need now to use your Qt account to access the pre-built binaries (the same you use to post here)

                      mzimmersM Offline
                      mzimmersM Offline
                      mzimmers
                      wrote on last edited by
                      #17

                      @SGaist thanks. Good thing they still exist, because I'm continuing to have nothing but trouble in my attempts to build the libraries. I really should report my problems with this to someone; any suggestions?

                      1 Reply Last reply
                      0
                      • SGaistS Offline
                        SGaistS Offline
                        SGaist
                        Lifetime Qt Champion
                        wrote on last edited by
                        #18

                        The bug tracker is your friend :-)

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

                        mzimmersM 1 Reply Last reply
                        1
                        • SGaistS SGaist

                          The bug tracker is your friend :-)

                          mzimmersM Offline
                          mzimmersM Offline
                          mzimmers
                          wrote on last edited by
                          #19

                          @SGaist done. Thanks.

                          aha_1980A 1 Reply Last reply
                          0
                          • mzimmersM mzimmers

                            @SGaist done. Thanks.

                            aha_1980A Offline
                            aha_1980A Offline
                            aha_1980
                            Lifetime Qt Champion
                            wrote on last edited by
                            #20

                            Hi @mzimmers,

                            would you mind letting us know, where?

                            Thanks and regards

                            Qt has to stay free or it will die.

                            mzimmersM 1 Reply Last reply
                            1
                            • aha_1980A aha_1980

                              Hi @mzimmers,

                              would you mind letting us know, where?

                              Thanks and regards

                              mzimmersM Offline
                              mzimmersM Offline
                              mzimmers
                              wrote on last edited by
                              #21

                              Hi @aha_1980 - if you're referring to my bug report, it's here.

                              1 Reply Last reply
                              2

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