1

Disclaimer: I am not a native English speaker NOR am I versed in the law beyond the basics you learn in highschool-/uni-courses.


I am writing a software which uses LGPL licensed libraries. From studying the LGPL text (well mostly googling and reading explanations from random people on the internet) I understand that I will have to either have to

a) include binaries & sources of the used libraries with my software package
b) ship my software without the libraries and tell the user to get them themselves

I am wondering/unsure if my including a utility that downloads the required binaries onto the user's computer, instead of having them do it themselves, would be permissible/compliant to the license terms of these libraries?


Question: Would the practice described in the last paragraph work, or are there issues that contradict with the license?


Linking: https://www.gnu.org/licenses/gpl-faq.html#LGPLStaticVsDynamic
LGPLv3: https://www.gnu.org/licenses/lgpl-3.0.en.html
GPLv3: https://www.gnu.org/licenses/gpl-3.0.html

1

I understand that I will have to either have to

a) include binaries & sources of the used libraries with my software package

This is not correct. You can redistribute binaries without the sources and the sources without the binaries. In all versions of the LGPL, you need to eventually redistribute the corresponding source code if you only redistribute the binaries. The GPL 3.0 section 6 explains how you can handle the redistribution of the corresponding source code when you redistribute a binary (and this is in the GPL and not the LGPL 3.0 text, the former being incorporated by reference in the LGPL 3.0 text) and there are at least six different ways.

b) ship my software without the libraries and tell the user to get them themselves

This is not correct. You can include the libraries alright and redistribute the corresponding source code for the LGPL-licensed library either bundled or separately from your software product. Depending whether or not the LGPL-licensed library has been modified and how your code interacts with this library you may have additional obligations and the copyleft may extend in some cases to your own code calling this library.

I am wondering/unsure if my including a utility that downloads the required binaries onto the user's computer, instead of having them do it themselves, would be permissible/compliant to the license terms of these libraries?

This may be OK in some cases but will never comply with the spirit of the license (beside being a major pain for your users)... Furthermore, if you are for instance using a programming language that compiles to native code such as C/C++ and are dynamically linking with the LGPL-licensed library, you are de facto incorporating header includes in your own binary which makes the separate user installation of the library a rather moot point.

  • Thank you for the elaboration on these points; If I may inquire about your chosen wording: beside being a major pain for your users -> As an enduser I am usually delighted when I get the choice to either press a button and download additional things needed for the software, or can download these myself from the source I prefer; instead of having to dig into install paths to replace things that I did not want in the first place (similarly extends to choosing an installation directory myself). || Did you refer to that, or was the wording in my question misleading? – dot_Sp0T Dec 28 '16 at 9:08
  • 1
    As an end user, I like things that work and require as little configuration and fiddling as possible. This is for applications but also for libraries. In my book, if I cannot download and run or use, then this is a big minus. – Philippe Ombredanne Dec 28 '16 at 10:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.