The Free Software Foundation is of the opinion that a program that links a library is a derivative work of that library, so a program that links to a GPL-licensed library would need to be distributed under the terms of the GPL. That is what I understood from the following posts:
- What are the arguments for considering dynamic links to constitute derivative works?
- Is it allowed to dynamically link a GPL licensed library for commercial use?
However, the Eclipse Software Foundation has the opposite interpretation. In the Eclipse Public License 2.0 FAQ, merely using the interface of a library does not create a derivative work:
5.3. I’m programmer not a lawyer, can you give me a clear-cut example of when something is or is not a derivative work?
If you have made a copy of existing Eclipse code and made a few minor revisions to it, that is a derivative work. If you’ve written your own Eclipse Platform plug-in with 100% your own code to implement functionality not currently in Eclipse, then it is not a derivative work. Scenarios between those two extremes will require you to seek the advice of your own legal counsel in deciding whether your program constitutes a derivative work.
For clarity, merely interfacing or interoperating with Eclipse Platform plug-in APIs (without modification) does not make an Eclipse Platform plug-in a derivative work.
My question is: why are interpretations of "derivative works" confined to FAQs instead of being placed directly into the license text? If the definition of what constitutes "derivative works" were to be explicitly stated in the license text, there would be less need for all these opinions and interpretations. Why not explicitly state what "derivative works" includes and excludes like in the Apache License 2.0?
"Derivative Works" shall mean any work, whether in Source or Object form, that is based on (or derived from) the Work and for which the editorial revisions, annotations, elaborations, or other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof.