[Interest] Qt LGPLv3 and Qt LGPL Exception

[Tuukka Turunen]

> -----Original Message-----
> From: Interest [mailto:interest-bounces+tuukka.turunen=qt.io at qt-
> project.org] On Behalf Of Benjamin TERRIER
> Sent: keskiviikkona 29. kesäkuuta 2016 9.13
> To: qt qt <interest at qt-project.org>
> Subject: Re: [Interest] Qt LGPLv3 and Qt LGPL Exception
> 
> 2016-06-28 20:53 GMT+02:00 André Somers <andre at familiesomers.nl>:
> >
> >
> >
> > Op 28/06/2016 om 11:09 schreef Jean-Michaël Celerier:
> >
> >
> > On Tue, Jun 28, 2016 at 10:39 AM, Benjamin TERRIER
> <b.terrier at gmail.com> wrote:
> >>
> >> The technical reason is that when including Qt headers in proprietary
> >> software, your final binary contains compiled forms of Qt code (e.g
> >> inline function or template classes).
> >
> >
> > From the LGPLv3 :
> >
> > 3. Object Code Incorporating Material from Library Header Files.
> >
> > The object code form of an Application may incorporate material from a
> header file that is part of the Library. You may convey such object code under
> terms of your choice, provided that, if the incorporated material is not limited
> to numerical parameters, data structure layouts and accessors, or small
> macros, inline functions and templates (ten or fewer lines in length), you do
> both of the following:
> >
> > So... How exactly do you use any of the Qt containers using the LGPL3
> libraries? Are they implemented in 10 or less lines of template code?
> >
> > It think the question is valid, and reading the question, you can see that he
> read that passage.
> >
> > André
> >
> > a) Give prominent notice with each copy of the object code that the Library
> is used in it and that the Library and its use are covered by this License.
> > b) Accompany the object code with a copy of the GNU GPL and this license
> document.
> >
> >
> >
> > Best
> > Jean-Michaël Celerier
> >
> >
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> 
> 
> It appears I misread the LGPLv3 and that there are no issues with Qt.
> 
> I thought the exception was only valid for inline functions of less than 10
> lines. Whereas in reality the exception is always valid, but requires you only
> to give credits if there is such a function.
> 
> It seems I'm not the only one on the Internet to misread this part when
> reading it fast :-/
> 
> Sorry about all the fuss.
> 

It is actually very good that these kind of items are asked. 

No longer needing to have similar LGPL exception with v3 was, of course, known and analyzed when the new licensing was decided. But it seems that we have not updated the licensing FAQ (http://qt.io/faq) about it and it clearly is not a self-evident topic. 

Yours,

	Tuukka

> Cheers,
> 
> Benjamin
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