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Licensing question



  • Hi,

    I want to develop a tool which should help a lot of people (in the security area). It's basically two projects, one "core" which does calculations and a GUI written with QT for visualisation of the calculations.

    I'm developing the "core" (which is not developed with QT) during my worktime at my employee and the GUI in my spare time (the GUI is just for the community for which I develop it so that the tool is more simple to use; it's not for my company)

    The source code of both projects will be published and open sourced. However, my company requests that the tool will later be named "company-name toolname" when we publish it because I'm developing it during worktime (the core).

    My question now is:
    Am I allowed to use the free QT license for this? Since I'm developing the GUI (all QT stuff) in my spare time and we publish all source codes, I hope that this is allowed? However, the (free) tool will have my company name in it. I'm asking this because if it's not allowed I would not start to develop the GUI, however, I think the GUI will help a lot of people to use the free tool.


  • Lifetime Qt Champion

    Hi,

    The branding of your application has not much to do with the constraints of using the LGPL/GPL version of Qt. Just respect them and you'll be fine.

    By the way, it's Qt, QT stands for Apple's QuickTime which is likely not what you are going to use.



  • Thank you very much for your answer!

    One more question:
    What I want is: Other people (private persons, students, researchers, developers of their own code, ...) should be allowed to use my application. The application basically finds security vulnerabilities in software. I therefore don't want that another security company just takes my free application and sells a service with it. Is this somehow possible to forbid?

    As far as I understand I would publish my source code under GPLv3 license (as requested by Qt) which does not forbid commerical use.
    That means company ABC could fork my application, rebrand it from company XYZ to "company ABC security tool" and then start to sell a service with it?

    How do developers typically protect against this? Would it be possible that I publish the "core" project with a license which forbids commerical use (which license can be used for that?) and the GUI under GPLv3? The GUI is basically just a wrapper for the ~300 command-line options and verifies if the selected options together make sense.

    Am I allowed to publish the two projects with different licenses?


  • Lifetime Qt Champion

    You should consider contacting a lawyer for all these questions.


  • Moderators

    @Nobodyxxx said in Licensing question:

    As far as I understand I would publish my source code under GPLv3 license (as requested by Qt)

    Note that most Qt modules are available under the LGPLv3 license too.

    @Nobodyxxx said in Licensing question:

    Am I allowed to publish the two projects with different licenses?

    Yes.

    As @SGaist said, you should consult a lawyer for definite answers to all your questions. (Does your company have a legal team?)

    Here is some reading material to get you started:



  • Hi,

    yes my company has a lawyer and we will contact him. I just wanted to get some background / knowledge in that field first.

    May I ask a final question?
    So the GPLv3 license from Qt requires that I publish the source code of my application (I know that LGPL can also be used, but I want to publish the source code). Does that mean that I have to make the source accessable from the beginning?
    E.g.: I would like to develop the application some months and then publish all the code on one day. Is that possible or do I have to push all git commits every day to a public open repo?

    edit: And thanks for the links!!


  • Moderators

    @Nobodyxxx said in Licensing question:

    yes my company has a lawyer and we will contact him. I just wanted to get some background / knowledge in that field first.

    This would be best, especially since your questions involve software owned by your company (even though you're the one who's writing it)

    May I ask a final question?

    Sure.

    So the GPLv3 license from Qt requires that I publish the source code of my application (I know that LGPL can also be used, but I want to publish the source code).

    The GPLv3 is more than just about publishing source code. It is about freedom for users to study and modify software. Source code is just one part of this freedom; another part is that GPL'ed code cannot be used in a DRM system, even if the source code of the system is published.

    Anyway,

    • If you use Qt under the GPLv3 license, then your own software must also be released under GPLv3
    • If you use Qt under the LGPLv3 license, then in many cases your own software can be released under any license you want (including GPLv3!)
      • Your lawyer can tell you when you can and can't choose your own license

    Does that mean that I have to make the source accessable from the beginning?
    E.g.: I would like to develop the application some months and then publish all the code on one day. Is that possible or do I have to push all git commits every day to a public open repo?

    No.

    The GPL requires you to share your source code with people who have access to your software. If you haven't released your software, then nobody has access to it so you have to share your source code with nobody.

    edit: And thanks for the links!!

    You're welcome. All the best with your projects!

    Please understand: It's not that @SGaist and myself don't want to answer your questions; it's just that the answers are complex and depend on many different things.


  • Lifetime Qt Champion

    To add to @JKSH : we are not lawyers.


  • Moderators

    @SGaist said in Licensing question:

    To add to @JKSH : we are not lawyers.

    Oh yeah... I forgot about that part... :-D



  • Thank you both again for your time! I think I now know everything I need to know and we will contact our lawyers.


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