Swish-e is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See below for version 2 of the GNU GPL. Unless otherwise indicated, all source files are Copyright (C) 2005, the Swish-e Project, http://swish-e.org. Swish-e includes a library for searching with a well-defined API. The library is named libswish-e. Linking libswish-e statically or dynamically with other modules is making a combined work based on Swish-e. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of Swish-e give you permission to link Swish-e with independent modules that communicate with Swish-e solely through the libswish-e API interface, regardless of the license terms of these independent modules, and to copy and distribute the resulting combined work under terms of your choice, provided that every copy of the combined work is accompanied by, or provides a URL link to, a complete copy of the source code of Swish-e (the version of Swish-e used to produce the combined work), being distributed under the terms of the GNU General Public License plus this exception. An independent module is a module which is not derived from or based on Swish-e. Note that people who make modified versions of Swish-e are not obligated to grant this special exception for their modified versions; it is their choice whether to do so. The GNU General Public License gives permission to release a modified version without this exception; this exception also makes it possible to release a modified version which carries forward this exception. GNU GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 0. This License applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any derivative work under copyright law: that is to say, a work containing the Program or a portion of it, either verbatim or with modifications and/or translated into another language. (Hereinafter, translation is included without limitation in the term "modification".) Each licensee is addressed as "you". 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Frequently Asked Questions about the Swish-e License
- So what's the deal with the special exception to the standard GPL?
The GNU GPL allows for a special exception to the "tainting" behaviour of the GPL. See http://www.gnu.org/licenses/gpl-faq.html#LinkingOverControlledInterface for the official description.
In order to settle some ambiguities within the Swish-e source code, the developers decided to switch from the LGPL license under which Swish-e had originally been released to the standard GPL license. This is allowed (and often encouraged) under both licenses.
However, in order to allow other software projects to continue to link against the Swish-e searching library (libswish-e) and to continue to give other open source projects the freedom to use their own open source licenses, the special exception clause was invoked. This clause makes the Swish-e library and its API available under similar terms to the original LGPL, while putting the entire Swish-e project under the umbrella of the GPL.
We know this kind of legal hairsplitting can appear clever and needlessly subtle. The developers tend to agree. The developers also want to protect ten years of community effort from being used in closed, proprietary ways, while still allowing other open source efforts the freedom to use non-GPL licenses. Hence this compromise.
Contact the Swish-e discussion list with any questions about the Swish-e license.
- I want to develop a new API interface to Swish-e in [insert your favorite programming language here]. Can I do that under the Swish-e License?
- Why yes, you can! See FAQ #1.
- Why did you switch from the LGPL? You've ruined [insert name of your favorite project here]!!
If you've got a project that depends on Swish-e and the LGPL, then you're probably familiar with the Swish-e source code. And therefore, you're probably also familiar with the fact that Swish-e is a smorgasbord of LGPL, GPL, BSD, MIT, public domain and other licenses.
The original "purity" of the LGPL status of Swish-e has long been in debate and as a consequence, Swish-e's licensure has been in limbo for years. That limbo worked for a while (hey, we're all friendly here right?), but in response to a specific request for the status of the Swish-e license, a thorough review was made of the source code. The result was the decision to officially declare ourselves a GPL'd project, but with the special exception for linking against libswish-e (see FAQ #1).
If the new Swish-e License still boggles you and ruins your day, feel free to contact the discussion list. We can probably sort something out.
- What version(s) of Swish-e does this license apply to?
- The Swish-e License is applicable to the 2.4.x release branch of Swish-e.
- I'm confused. Are you saying that "we are GPL, but unlike normal GPL, we don't force you into GPL for using the code"?
- No. We're saying "we can't force you into GPL for linking against the libswish-e library." That's just a little slice of the Swish-e pie. If you wanted to make a derivative work of the Swish-e code (like a Super-Swish), you can not release it without the GPL. (You could if Swish-e were still under the LGPL. But it's not.)
- You mean I can use Swish-e in my project without obligation?
Well, not exactly. You have to provide source code for the actual version you use (you may point to swish-e.org if you use an unmodified version of the software and state the version).
In addition to that legal requirement, there are some strong recommendations that aren't legally required. You should make it clear to your users that you are using Swish-e in your product by listing Swish-e in your documentation and, if you have a web site, with an easy to find link on your web site. (Consider using the Swish-e logo). You must feel guilt if you add features or bug fixes to the software and do not inform other users of swish-e via the Swish-e discussion list, and you should think about buying the developers a beer. Or two. Or until they say 'stop'.