LGPL license and "open" consumer device obligation with embedded.



  • Hello

    I made a lot of googling but not have found a concrete answer on the question:
    How Qt Company understands the obligation "Must make open" consumer device? From https://www.qt.io/download.

    Let's suppose that I want to use Qt Open Source and develop the device with all its hardware connected to Linux machine running the Qt application - user graphical interface with the device. And I want to make the app source code closed with compliance to all LGPL requirements.

    So how I should consider the Qt "open consumer device" term in my case?

    Does it mean I have to:

    1. provide the user, physical ability to get into my Linux machine in order to for example use another version of Qt Libraries (used by my app) - to provide the user permissions which give the LGPL license.

    or...
    2. make open hardware (like providing all schematics etc.) as well with the abilities in mentioned in 1.

    or something else that I don't get?

    So If 1. is possible. Are there other issues that I should know about?


  • Qt Champions 2017

    I don't know how devices relate to the licensing, and I'm not a lawyer. However, the LGPL dictates that when you distribute your software you must provide for the user to be able to relink the library that is under LGPL. This means:

    1. When linking statically - providing object files of the software, so the user can link it with his/hers own copy of the library.
    2. When linking dynamically - satisfied by itself.

    Note there are additional clauses, as far as I recall, that you need to keep a copy of the (exact) source from which the library is built to allow for later inspection. Again, these questions are best directed to a copyright solicitor, not to a user forum. Threat the above as general-purpose information.

    PS. Perhaps you could ask the Qt Company to clarify even.



  • Thanks @kshegunov. Yes, I asked some time ago Qt Company, but for now, there is no answer yet. So I was hoping to find someone here, who have had a similar problem and will be able to point me to valuable remarks or further steps.



  • Some time ago Qt published webinar concerning the topic, which helped me a lot.

    I am adding a link for future readers: https://resources.qt.io/videos/complying-with-the-requirements-of-the-gpl-lgpl-v3-license-on-demand-webinar