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How to correctly Connect from qthreadpool

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qthreadpoolsignalslots
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  • SGaistS Offline
    SGaistS Offline
    SGaist
    Lifetime Qt Champion
    wrote on last edited by
    #2

    Hi,

    Do you mean from your QRunnable subclass ?

    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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    • P Offline
      P Offline
      PXLFuSSeL
      wrote on last edited by PXLFuSSeL
      #3

      Hy,
      thats what i mean.

      i have implemented a QRunnable to do that work.
      Then i loop through a list were the params in, create an object, connect the signal and slot, and start the work with pool->start().

      But all i get is "Function recv() failed" on console but no entrie in my list.
      Is that correct? Or shall i implement an own kind of threadpool?

      regards,

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

        Since you have a list of parameters that you iterate, why not use QtConcurrent::map and QFutureWatcher ?

        You'll have the progress indication for free.

        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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        • P Offline
          P Offline
          PXLFuSSeL
          wrote on last edited by
          #5

          I know Threadpools from python and thought it works the same way.
          But ok i will give that a shot.

          QImage scaled(const QImage &image)
          {
          return image.scaled(100, 100);
          }

          QList<QImage> images = ...;
          QFuture<QImage> thumbnails = QtConcurrent::mapped(images, scaled);

          like that?

          Thx

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

            Yes, adding a QFutureWatcher in the mix.

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

            P 1 Reply Last reply
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            • SGaistS SGaist

              Yes, adding a QFutureWatcher in the mix.

              P Offline
              P Offline
              PXLFuSSeL
              wrote on last edited by
              #7

              @SGaist
              hey is there also a way to get the already compute results while running?
              So i want to update the gui, as soon as an results is computed.
              Or isnt it a good idea?

              jsulmJ 1 Reply Last reply
              0
              • P PXLFuSSeL

                @SGaist
                hey is there also a way to get the already compute results while running?
                So i want to update the gui, as soon as an results is computed.
                Or isnt it a good idea?

                jsulmJ Offline
                jsulmJ Offline
                jsulm
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @PXLFuSSeL You get the result from QFuture and then update the GUI. Using QFutureWatcher (as @SGaist suggested) you also get notification when a job is finished and then use QFuture to get the result.

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

                P 1 Reply Last reply
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                • jsulmJ jsulm

                  @PXLFuSSeL You get the result from QFuture and then update the GUI. Using QFutureWatcher (as @SGaist suggested) you also get notification when a job is finished and then use QFuture to get the result.

                  P Offline
                  P Offline
                  PXLFuSSeL
                  wrote on last edited by
                  #9

                  @jsulm yes that is implemented, but i am interested in getting a result as soon as it is calculated, because am working with really big lists

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

                    As already hinted twice, QFutureWatcher 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

                    P 1 Reply Last reply
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                    • SGaistS SGaist

                      As already hinted twice, QFutureWatcher is your friend.

                      P Offline
                      P Offline
                      PXLFuSSeL
                      wrote on last edited by
                      #11

                      @SGaist yes, thx, my fault was trying to iterate through the future until not be ready.
                      now i got what i want, not as fast as i want, but it works stable.

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