Re: LGPL Considered Viral in Java
5. A program that contains no derivative of any portion of the Library, but is designed to work with the Library by being compiled or linked with it, is called a "work that uses the Library". Such a work, in isolation, is not a derivative work of the Library, and therefore falls outside the scope of this License.Emphasis mine. I am not a lawyer, this is not legal advice, but it seems to me that 1) The portion I highlighted has significance in making the decision and 2) even if it is a "work that uses the Library", then if falls under section 6b).
However, linking a "work that uses the Library" with the Library creates an executable that is a derivative of the Library (because it contains portions of the Library), rather than a "work that uses the library". The executable is therefore covered by this License. Section 6 states terms for distribution of such executables.
When a "work that uses the Library" uses material from a header file that is part of the Library, the object code for the work may be a derivative work of the Library even though the source code is not. Whether this is true is especially significant if the work can be linked without the Library, or if the work is itself a library. The threshold for this to be true is not precisely defined by law.
If such an object file uses only numerical parameters, data structure layouts and accessors, and small macros and small inline functions (ten lines or less in length), then the use of the object file is unrestricted, regardless of whether it is legally a derivative work. (Executables containing this object code plus portions of the Library will still fall under Section 6.)
Otherwise, if the work is a derivative of the Library, you may distribute the object code for the work under the terms of Section 6. Any executables containing that work also fall under Section 6, whether or not they are linked directly with the Library itself.
6. As an exception to the Sections above, you may also combine or link a "work that uses the Library" with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer's own use and reverse engineering for debugging such modifications.
You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License. If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License. Also, you must do one of these things:
[...]
- b) Use a suitable shared library mechanism for linking with the Library. A suitable mechanism is one that (1) uses at run time a copy of the library already present on the user's computer system, rather than copying library functions into the executable, and (2) will operate properly with a modified version of the library, if the user installs one, as long as the modified version is interface-compatible with the version that the work was made with.
Regardless, this is the Apache Software Foundation's opinion only. Most other open source groups do not take such a conservative view with Java.
Also, reading the [link|http://superlinksoftware.com/text/lgpl.txt|email] lends a different interpretation. Read Turner's comment at the very end of the blog:
Comment by: David Turner -
Left on: Thu Jul 17 23:07:14 EDT 2003
Jonabell, I'm not a lawyer. I'm a licensing guy. I know how to program in Java (although I prefer Perl or Python). I understand, at an operational level, how Java does libraries. My message is that the LGPL works basically the way everyone has always thought it does -- that it is not the same as the GPL. Of course, not everyone knew about the reverse engineering stuff in Section 6, but it's not a secret -- it's mentioned in the GPL Quiz on FSF's site, for instance. Fred Grott, the CPL is much closer to the GPL than the LGPL.