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confused about Qt QPL/GPL license

Tuesday, 26 August 2003  |  jason harris

(EDIT: changed the title. Thanks for the discussion, I am less confused now :) )

How many of you, when confronted with the Qt licensing option (during the 'configure' step of the compile) select the GPL as your Qt/X11 license? I had always done so, but I have come to understand that using KDE precludes this option.


If you use KDE, the QPL is your only non-commercial licensing option, because a GPL'd library cannot be linked with non-GPL code. KDE contains lots of this. Here's a partial list, just of the core apps and libs:

  • kdelibs (LGPL)
  • kwin (BSD)
  • kicker (BSD)
  • ksmserver (BSD)
  • klipper (Artistic)
There are many more besides these.

Anyway, just some food for thought. Since there's no *explicit* choice made between QPL and GPL, I guess anyone who mistakenly chose the GPL like I did can just retroactively change their mind and continue using Qt under the QPL. I have heard the opinion that the Qt licensing option can be interpeted as allowing the user to decide on a per-application basis which license they will use, but I can't really buy that. Besides, it doesn't matter since kdelibs is LGPL'd, and therefore can't be linked with GPL'd Qt/X11. (EDIT: actually, combining a GPL'd lib with a LGPL'd lib can be allowed, *if* the resulting app is GPL'd. So maybe there's hope for this "per-application" Qt licensing meme, though it still seems like a huge stretch to me)

BTW, why not eliminate the GPL option in qt-copy? It just adds confusion.

(EDIT: how am I supposed to insert paragraph breaks? it doesn't recognize the p tag, so I used two br's in a row)