[Interest] Qt Creator licensing for companies with Qt Commercial developers

Jérôme Godbout godboutj at amotus.ca
Tue Mar 31 16:56:42 CEST 2020

the mix is not a corner case, it’s the reality of many people around. We are a services compagnie, and this is really a headache to understand where it should fall since we do project for client but we are a single cie. The license of Qt have is such an ambiguity and our lawyer recommend (not even sure himself where we do fall) we avoid using it as much as we can given the context we are in. When a client have commercial license, we ask them to use their infrastructure and avoid having any commercial license on premise (we cannot take any chance). If you think your licensing is clear and make it easy, it ain’t, we do more and more Xamarin, just for license reason not because we like it.  I continue Qt mostly on hobby, really like Qml and where the binding in C++ is heading. But for my work job, Qt is fading out.

The departure between mixing LGPL and Commercial one is such a gray area, nobody want to venture anywhere there.

Note: I don’t speak in the name of my cie, but my own opinion here. Just stating the fact that the Qt license is the main reason we often ditch Qt for some application.

From: Interest <interest-bounces at qt-project.org> On Behalf Of Tuukka Turunen
Sent: March 31, 2020 10:33 AM
To: Andy <asmaloney at gmail.com>
Cc: interest at qt-project.org
Subject: Re: [Interest] Qt Creator licensing for companies with Qt Commercial developers

Hi Andy,

You are asking to explicitly define terms like project, company, product. These are rarely possible to define outside of the generic use of the term and each individual contract. I assume you understand that it is not possible to take any stand of those in an email. We have these listed in the FAQ and contracts in as clear way as we have been able to list these.

I have also tried to explain these, but your tone feels rather aggressive. I do not understand what makes you say: “Even a solo developer needs to hire a lawyer before touching anything Qt-related.” For most of the situation the licensing of Qt is really simple and also very permissive. Yes, there are certain complex corner cases, like mixing of commercial on open-source versions of the Qt framework/tools. But how often do you need to mix these? Most of the Qt users are using either the commercial or the open-source version.



From: Andy <asmaloney at gmail.com<mailto:asmaloney at gmail.com>>
Date: Tuesday 31. March 2020 at 16.47
To: Tuukka Turunen <tuukka.turunen at qt.io<mailto:tuukka.turunen at qt.io>>
Cc: Giuseppe D'Angelo <giuseppe.dangelo at kdab.com<mailto:giuseppe.dangelo at kdab.com>>, "interest at qt-project.org<mailto:interest at qt-project.org>" <interest at qt-project.org<mailto:interest at qt-project.org>>
Subject: Re: [Interest] Qt Creator licensing for companies with Qt Commercial developers

> "This is at the moment not listed as an allowed case..."

And this again is here the Qt company is digging it's own grave.

What constitutes a "product"? If a company has one team working on an open source library and another team using it in a proprietary application - what then? What if an internal tool uses some code or a library from proprietary application? What if...

Even a solo developer needs to hire a lawyer before touching anything Qt-related.

Once you start trying to codify all the different scenarios in your licensing, it becomes toxic and people will avoid it

Andy Maloney  //  https://asmaloney.com
twitter ~ @asmaloney<https://twitter.com/asmaloney>

On Tue, Mar 31, 2020 at 9:36 AM Tuukka Turunen <tuukka.turunen at qt.io<mailto:tuukka.turunen at qt.io>> wrote:


The point of the "Prohibited combination" is to prevent a company or a chain of companies (like in a typical subcontracting scenario) from making part of the product with non-paid Qt and part with paid. Qt being as defined in the commercial license agreement, i.e. including tools and framework. This was what the person initiating this mail thread asked about. I do agree that it gets complex when one starts including items created by an independent third party. This is at the moment not listed as an allowed case, even though it is not something we specifically aimed to prevent.



On 31.3.2020, 15.03, "Interest on behalf of Giuseppe D'Angelo via Interest" <interest-bounces at qt-project.org<mailto:interest-bounces at qt-project.org> on behalf of interest at qt-project.org<mailto:interest at qt-project.org>> wrote:

    On 3/31/20 1:22 PM, Tuukka Turunen wrote:
    > For completely independent projects/products this is fine. Note that these really should not be same or in practice the same - or in any way depending, relating, using etc each other as defined in the license agreement.
    > See licensing FAQ question 2.7 athttps://www.qt.io/faq/<http://www.qt.io/faq/>  and License agreement athttps://www.qt.io/terms-conditions/<http://www.qt.io/terms-conditions/>

    It is still unclear if the usage of Qt _Creator_ for developing some
    code would cause such code to fall under the restrictions of commercial

    Here's a few scenarios:

    1) I have a Qt commercial license. In my project using commercial Qt I
    want to use a library developed by

    1a) some other team in my company;
    1b) someone else.

    This other library is under a liberal license; does NOT use Qt itself in
    any way; but has been developed using Qt Creator (GPL). Can I use it in
    my product under the commercial license? Or would it fall under the
    "Prohibited Combination":

    > “Prohibited Combination” shall mean any means to (i) use, combine, incorporate, link or integrate Licensed Software with any software created with or incorporating Open Source Qt, (ii) use Licensed Software for creation of any software created with or incorporating Open Source Qt

    Does "created with" here extend to GPL Creator?

    2) Same as 1, but this time with the library using Qt (as in: using
    headers, linking against it). Example: a Qt-based library coming from
    KDE Frameworks, developed using Creator.

    Giuseppe D'Angelo | giuseppe.dangelo at kdab.com<mailto:giuseppe.dangelo at kdab.com> | Senior Software Engineer
    KDAB (France) S.A.S., a KDAB Group company
    Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
    KDAB - The Qt, C++ and OpenGL Experts

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