Have you ever used GPL library for writing non-GPL software?

Question

While reading article A Practical Legal Guide to iPhone Application Development I was wondering by information in comment titled "“Dynamic linking” and the GPL".

There are opposing views within the legal community regarding the “dynamic linking”-“derivative work” issue as it relates to the GPL license; and no U.S. court has yet definitively ruled on the subject.

Therefore, to avoid potential confusion, until there is clear legal precedent, the following Practice Point has been removed from the article.

PRACTICE POINT

To avoid inadvertently “infecting” your proprietary software with the “viral” effect of the GPL license, your product should “dynamically link” to the open source components when it is running so that your proprietary code and the open source code are not considered as a single work subject to the GPL license, which would be the legal result if the open source components were “statically linked.”

Having googled, I managed to find that there different points of view on whether or not non-GPL software can legally statically link or dynamically link to GPL libraries. Wikipedia has a short overview of them.

I understand that SO is not a place for lawyers so I'm just interesting in have you ever used GPL library for writing non-GPL software?

Answer 1

Yes, many times - but as it was never distributed outside of the company, the GPL never takes effect and thus it's fine.

Answer 2

No, I haven't. Although untested in court, the FSF claims that even dynamically-linking to a GPL-licensed library constitutes a derivative work.

But beyond the legal issues, I look at this as an ethical issue. The reason most authors release a library (or other software) under the GPL is because they want others who benefit from the use of their code to release their code in the same fashion. Put another way, I expect users to respect the license of the software I write, so I should, in turn, respect the license of software that others write. If I don't want to adhere to the spirit of the GPL, I'm free to use another library with licensing terms that are compatible with my own.

(Of course, I've linked to and modified GPL-licensed libraries and software for internal use, but that's okay -- the GPL explicitly states that if you don't distribute your work, the licensing terms don't apply to you.)

Answer 3

http://stackoverflow.com/questions/3248823/legal-question-about-the-gpl-license-net-dlls/3249001#3249001 gives an example of how a GPL library can be "used" in a non-GPL application (that is made available to other people) by dynamic linking. I think that's about as close as you're going to get.