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Using Qt for Open Source project that doesn't use GPL license



  • I'm the "lead" developer for DeepSkyStacker

    DeepSkyStacker uses the BSD 3-Clause license, not GPL/LGPL. Reading about Qt for OpenSource guidance, I'm unclear whether I am allowed to use Qt under the OpenSource license or not.

    I do hope this won't be an obstacle ...

    David


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    WARNING I am not a lawyer so the only correct answer here is: ask a lawyer.

    As for my understanding of these licenses:

    • You can use a LGPL library with your project that is BSD licensed. You need to abide by the constraints of the LPGL though meaning that if you provide binaries of your application, your users must be able to swap the Qt libraries for their own and you also must provide a place that cites that you are using Qt (the easiest is using the QApplicatoin::aboutQt slot. These two points are not Qt specific though, it will apply to all LGPL libraries you might be using. One other thing is that if you modify Qt itself for some reasons, you have to provide these patches as well.

    • If you are using Qt under GPL, then it's the GPL that kicks in and all your code shall be GPLed so I don't think that it is what you are after.



  • I most definitely don't wish to catch the GPL virus - which is why I asked - its a royal pain (tm) that some parts of Qt are under a viral license (GPL) that REQUIRES you to use that license if you use any GPL code in your stuff. I'm just not doing that! We are quite happy with the BSD license for our code and have no wish to be forced to change. So I won't be using QtChart ...

    David


  • Lifetime Qt Champion

    Then you might be interested by Qwt


  • Moderators

    @Perdrix Just don't use the GPL parts then. Most of Qt is available also under LGPL which is compatible with BSD as far as I can see (IANAL). There are only a couple of modules that are not available under LGPL so as long as you don't use those you are in the clear.


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