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Mix commercial and open source

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  • J Offline
    J Offline
    JohannesW
    wrote on 22 Feb 2024, 21:23 last edited by
    #1

    Actually, it's clear that you can't mix commercial and open source.

    Does this also apply if a company works open source and an external company develops a commercial sub-application, but links the open source Qt dynamically? Without static linking, so that in the end only the open source Qt remains?

    Or are you not allowed to mix things under any circumstances, even if it only affects the development?

    I don't expect a legally certain answer, just an empirical value.

    V S K 3 Replies Last reply 22 Feb 2024, 21:26
    0
    • J JohannesW
      22 Feb 2024, 21:23

      Actually, it's clear that you can't mix commercial and open source.

      Does this also apply if a company works open source and an external company develops a commercial sub-application, but links the open source Qt dynamically? Without static linking, so that in the end only the open source Qt remains?

      Or are you not allowed to mix things under any circumstances, even if it only affects the development?

      I don't expect a legally certain answer, just an empirical value.

      V Offline
      V Offline
      Volker75
      wrote on 22 Feb 2024, 21:26 last edited by
      #2

      @JohannesW Impossible to answer that, because there are a lot of different open source licenses available. You must tell us about wish open source license you are talking. Because sometimes it is allowed and sometimes it is not allowed, depending on the open source license.

      J 1 Reply Last reply 22 Feb 2024, 21:33
      1
      • V Volker75
        22 Feb 2024, 21:26

        @JohannesW Impossible to answer that, because there are a lot of different open source licenses available. You must tell us about wish open source license you are talking. Because sometimes it is allowed and sometimes it is not allowed, depending on the open source license.

        J Offline
        J Offline
        JohannesW
        wrote on 22 Feb 2024, 21:33 last edited by
        #3

        @Volker75 GPLv2/GPLv3 and LGPLv2/LGPLv3
        But I thought there were Qt specific conditions?

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        • V Offline
          V Offline
          Volker75
          wrote on 22 Feb 2024, 22:19 last edited by
          #4

          @JohannesW Qt has a lot of different licenses, depending on the modules that you are using.

          It is allowed to link against LGPL code, as long as you still care about the LGPL. see https://www.qt.io/licensing/open-source-lgpl-obligations

          GPL, no, you are not allowed to link against them.

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          • J JohannesW
            22 Feb 2024, 21:23

            Actually, it's clear that you can't mix commercial and open source.

            Does this also apply if a company works open source and an external company develops a commercial sub-application, but links the open source Qt dynamically? Without static linking, so that in the end only the open source Qt remains?

            Or are you not allowed to mix things under any circumstances, even if it only affects the development?

            I don't expect a legally certain answer, just an empirical value.

            S Offline
            S Offline
            SGaist
            Lifetime Qt Champion
            wrote on 24 Feb 2024, 20:22 last edited by
            #5

            @JohannesW Hi,

            What exactly do you mean by commercial and Open Source ?

            Do you mean building a commercial application using Open Source libraries or mixing the Qt Open Source and Commercial licenses ?

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

            1 Reply Last reply
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            • J JohannesW
              22 Feb 2024, 21:23

              Actually, it's clear that you can't mix commercial and open source.

              Does this also apply if a company works open source and an external company develops a commercial sub-application, but links the open source Qt dynamically? Without static linking, so that in the end only the open source Qt remains?

              Or are you not allowed to mix things under any circumstances, even if it only affects the development?

              I don't expect a legally certain answer, just an empirical value.

              K Offline
              K Offline
              kshegunov
              Moderators
              wrote on 25 Feb 2024, 00:04 last edited by
              #6

              @JohannesW said in Mix commercial and open source:

              Or are you not allowed to mix things under any circumstances, even if it only affects the development?

              You are not allowed to mix code that was developed with Qt commercial license(s) and such that was developed with Qt's LGPL offering. TQtC's concern being that you can develop a whole system with LGPL and then decide that you want to jump to commercial to close the source completely (i.e. to decide you don't want oblige the requirements of the LGPL at some point after the code is already developed).

              In any case you can use the LGPL to develop commercial software, simply don't mix the licenses.

              Read and abide by the Qt Code of Conduct

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              22 Feb 2024, 21:33

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