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LGPL license effects
by John on Friday 09/Jan/2004, @14:22
By using KDE dialogs, does it mean that a commercial app developed with Gtk under the LGPL license have to be under the GPL license or otherwise have to buy a license from Trolltech?
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Re: LGPL license effects
by uga on Friday 09/Jan/2004, @15:07
From my understanding point, unless you buy a Qt license, whatever app that links against Qt must either be GPL or QPL compliant. GPL implies that your app must be GPL too. QPL... well http://www.trolltech.com/licenses/qpl.html =)
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  • Re: LGPL license effects
    by ac on Friday 09/Jan/2004, @15:25
    Please stop spreading lies. GPL does not imply your app must be GPL. Period.
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    • Re: LGPL license effects
      by uga on Friday 09/Jan/2004, @15:37
      Ok. So I'm lying. What licenses are allowed to be linked against GPL?
      I know they must be opensourced. What else? Is LGPL allowed? I guess yes, but whatever that uses the first original lib must comply with GPL too, so you're submitted to the GPL license anyway.

      Now tell me, what's the difference?
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      • Re: LGPL license effects
        by Don Sanders on Friday 09/Jan/2004, @22:10
        The GPL FAQ may help answer your questions, and other common questions about the GPL:

        http://www.gnu.org/licenses/gpl-faq.html#WhatDoesCompatMean
        * What does it mean to say that two licenses are "compatible"?
        * What does it mean to say a license is "compatible with the GPL".
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        • Re: LGPL license effects
          by uga on Thursday 15/Jan/2004, @14:33
          Great, thanks! It's one of those things one always hears in discussions but nobody makes clear. Lets hope somebody will give a definite answer to the definition of "derivative" too....
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Re: LGPL license effects
by Anton Velev on Saturday 10/Jan/2004, @02:39
I think a smart solution can be like this:
1) write a small lib - set abstract classes that are LGPL
2) use in your app GTK+ and small lib only and you are still LGPL compilant so your app can be closed source commercial
3) release a GPL licensed implementation (of your small lib) of the classes that links against Qt
3*) and of course still have the "safe" plugin is GTK implementation of your small lib

the only problem then will be with the distribution since from my understanding you cannot distribute closed source and GPL packaged together.. but however if such plugin is widely adopted (in future) and all distros distrubute such plugins you should not care... more than that users will demand such thing since they want everything integrated
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  • Re: LGPL license effects
    by ac on Saturday 10/Jan/2004, @04:04
    Please stop spreading these lies about the GPL license. YOUR APP OR LIB DOES NOT HAVE TO BE GPL LICENSED TO LINK AGAINST KDE.

    So why would you have to release a separate GPL licensed implementation? Please, you have been spouting off on this issue FOREVER. It is time you EDUCATE YOURSELF on these issues.

    Here is the solution for people who can think:

    1) write a small lib - set abstract classes that are LGPL that load either GTK+ or Qt at runtime.

    That's it. That's all. No more license bullsh*t, it works and it's legal. Your proprietary closed source app can then use KDE dialogs for free. Simple.
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    • Re: LGPL license effects
      by Sarang on Saturday 10/Jan/2004, @06:16
      But dosn't linking to KDE automatically link the application to Qt? If a qt link is there, then you need their commercial license to write closed-source applications right?
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      • Re: LGPL license effects
        by Evan on Saturday 10/Jan/2004, @11:01
        In this scheme you wouldn't be linking with KDE. You'd dynamically link your application with a small library with stubs for file dialogs and stuff. This library would be LGPL or something, and would implement the file dialogs etc using GTK. No license issues there, obviously. Just a little indirection.

        Now, if someone wanted the programs on their computer to use Qt dialogs instead of GTK ones, they'd write a new dynamic library which implemented the same interface but used Qt as the backend. They'd then overwrite the first dynamic library with the new one, and boom, programs would magically have Qt dialogs.

        Obviously the second library would have to be GPL. But this isn't a problem--the GPL specifically allows you to do whatever the hell you want with GPL code, including linking with libraries having an incompatible license, as long as you don't distribute the result. Which you wouldn't need to do.

        That's merely one way of many perfectly legal and acceptible ways to accomplish this; it probably works a little differently in real life.

        And that doesn't even consider the approaches where distributing the source code is perfectly legal, but distributing a binary is not.
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    • Re: LGPL license effects
      by Iuri Fiedoruk on Saturday 10/Jan/2004, @09:17
      Man, thank you very much!

      Even that I was in favor of KDE being GPL even if you could not link agains it, your explanation is very welcome and I even think it should be printed in the main page or at least on some FAQs well visible, because there is a lot of FUD because of this GPL/KDE thing.
      Thanks again.
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      • Re: LGPL license effects
        by Kurt Pfeifle on Saturday 10/Jan/2004, @09:37
        > there is a lot of FUD because of this GPL/KDE thing

        You are right. The FUD is spread by top level representatives of KDE opponents. It then trickles down to the rank and file of the community at large, because some friends are repeating it.

        One effective way to counter FUD, is if more people at the grassroots level know the facts. If they speak up in every forum: as soon as they notice another grassroot friend to thoughtlessly repeat bits of it, they should calmly, friendly and backed up with facts and links counter any FUD with facts, figures and arguments.
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        • Re: LGPL license effects
          by Iuri Fiedoruk on Saturday 10/Jan/2004, @14:02
          Very well said.
          I used to use the kompany as a example that comercial software can be done using KDE libraries, but some time ago they started using more QT-only so I stopped using it. But knowing that you can write a little "wrapper" library to make possible writing non-GPL software for KDE (that is more or less that the kompany did) in such a well explained way is a great news that should be spread the most we can.

          (I'm writing a article for a brazilian site about this just now)
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    • Re: LGPL license effects
      by Anton Velev on Saturday 10/Jan/2004, @09:55
      AC, i think you should educate yourself by reading some news on the itnernet and the licenses.

      You know very well that whatever that is deriviated from GPL licensed soft must be GPL (except for Kernel and some other system libs).. anyway .. i think you can make your conlusion now.
      The question that John asked is for a commercial (i guess also closed source) app that is GTK written, and he wants to use KDE file dialog without messing with GPL.
      Of course (only if this QtGTK thing is not GPLd already) one may pay a some money to buy a commercial Qt license.

      I understand the question that John asked (comm GTK app + KDE filedialog) and hope my suggestion will be useful for his solution.


      PS: btw why don't you stay strong after your name, but trying to show the world you are MEN in the same time with unknown identity???
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      • Re: LGPL license effects
        by Allan Sandfeld on Sunday 11/Jan/2004, @06:53
        To things:
        1. What commercial applications use GTK? It just doesnt make sense to use an inferior but free toolkit when you are already paying for development.
        2. The KDE dialogs could by dynamically loaded, that way the application is not derivative, only the library, and the library could be LGPL.
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        • Re: LGPL license effects
          by uga on Thursday 15/Jan/2004, @14:24
          Did you read the definition given by Linus for "derivative"? There was quite a bit of discussion. That part of the license may indeed be the most tricky point. Lets hope GPL v3 will make these points clear :)
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  • Re: LGPL license effects
    by Kevin Krammer on Saturday 10/Jan/2004, @06:49
    > the only problem then will be with the distribution since from my understanding you cannot distribute closed source and GPL packaged together.

    No problem. The application vendor can distribute with the GTK implementation but the Linux distributor can distribute the Qt implementation.
    [ Reply To This | View ]

 
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