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Open source license, source code as an option.



  • Goodmorning, I have a question about the open source license.
    By reading the license I understand that I can sell my application created with the open source license providing together with the application the source code of QT and my application.
    My doubt is, I can make the source code available as an option in my application, let me explain better, I can do something like this:

    • My basic app costs 1000 USD (without source code)

    • My application with extended functions costs 3000 USD (without source code)

    • My application with extended functions and source code costs 6000 USD

    is it possible to do such a thing respecting the opensource license?
    Thanks in advance


  • Lifetime Qt Champion

    @Feiderico-Massimi Which license do you mean? If GPL then no, you can't ask for money if users ask for source code.
    If you're talking about LGPL then you do NOT have to provide your source code! You only have to provide the users the possibility to relink your app with their Qt version (usually that means to give them object files *.o).
    Note: I'm not a lawyer!



  • @jsulm said in Open source license, source code as an option.:

    usually that means to give them object files *.o

    That's a new one on me! I thought if one was linking against Qt libraries as *.so/*.dll files (as publicly available, obviously not altered) users wouldn't need any re-linking, just install new version of Qt shared libs and off they go?


  • Lifetime Qt Champion

    @JonB said in Open source license, source code as an option.:

    @jsulm said in Open source license, source code as an option.:

    usually that means to give them object files *.o

    That's a new one on me! I thought if one was linking against Qt libraries as *.so/*.dll files (as publicly available, obviously not altered) users wouldn't need any re-linking, just install new version of Qt shared libs and off they go?

    That's correct. The object files are needed in case it's a static build and it's therefore way more hassle to provide than use dynamic linking.



  • @SGaist
    Sorry to ask for clarification, but...

    Static linking has not been mentioned here. Let's say I'm in the absolute normal case: I am linking against dynamic Qt libraries, I have made no changes to them, my output is an executable. I do not have to supply my own sources. Are you/ @jsulm now saying I do need to supply my own files' intermediate *.o/*.obj, perhaps so that someone else can relink if they want to use static Qt libraries or something?

    I have not heard this before. I thought I understood it all, now I am confused...


  • Lifetime Qt Champion

    @JonB "The object files are needed in case it's a static build" - in case of static build.
    Since you talk about dynamic build you do not have to provide object files.


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