Ask the Chopping Block!

This month's question was:

I've don't know about the different licenses WorldForge uses. What are the good and bad parts about the different ones? Do I retain ownership of my work?


I hunted down novalis and he has given this answer.


Worldforge uses the following license: GPL, GFDL, GPL / GFDL disjunction, LGPL and X11-style. In all cases, you retain copyright on code you contribute.

The GPL (version 2 or greater) is the preferred license for all code. The GPL/GFDL disjunction is the preferred license for all artwork. The GFDL (version 1 or later) is the preferred license for text which will not go into games. For libraries which benefit the project more by becoming universal standards than by preserving the maximal amount of freedom, we recommend the LGPL (version 2.1 or greater). We chose these standards a few years ago by vote. In all cases, the individual developer may choose any license which is compatible with the GPL. For example, Jesse Jones prefers to use X11-style licensing for components he has created. This is OK -- they are automatically upgraded to the GPL when they are linked with GPL-licensed components. To find a list of GPL-compatible Free Software licenses, see the license list from the Free Software Foundation.

X11-style licenses are permissive -- they allow derivative works (usually new versions) to be made and distributed under any license at all, including proprietary software licenses. Most Worldforge developers have no interest in helping proprietary software in their spare time, so most of our code is under the GPL or LGPL.

The GPL allows derivative works, but these works must be released under the GPL with full source code. So, if anyone distributes a modified version of STAGE (which is released under the GPL) they must distribute it with full source code, under the terms of the GPL.

The LGPL is just like the GPL, except that certain classes of derivative works (those that use the LGPL-licensed work as a library) can be licensed under a non-LGPL license. Source code for the version of the library must be distributed with the derivative work. The derivative work must be built and licensed in such a way that new versions of the LGPL-licensed library can be linked with it.

The GFDL is similar to the GPL. It is intended for technical manuals, but is also useful for artwork. It contains requirements about distribution formats and attribution. We use the GFDL with the GPL for artwork so that our artwork can be used in GPL-licensed programs and GFDL-licensed documents like manuals.

In all cases, please read the actual text of the licenses carefully and be sure you understand them before distributing software. If you distribute verbatim copies (like a mirror site), you should not worry; verbatim copying is allowed with no restrictions. If you have specific WF-related licensing questions, ask me: novalis on IRC (irc.worldforge.org).

Once a work is licensed under any of these licenses, that version is available under that license until the copyright expires (which, given the current trend in copyright law, will never happen). The copyright holder can license new versions under whatever license she wants to, so long as they contain only code by the the original copyright holder, or the other copyright holders agree to allow this.

You can always find the license of WF software in the COPYING file at the root of the software's directory. If some piece of WF software is missing a COPYING file, please report that to the software's author.


Novalis works for the Free Software Foundation on their new GPL Compliance lab.


Well there is another question answered by the Chopping Block! Hoped this helped with all your Licensing Problems. Next month i'll get an answer for the question ""