GPL vs LGPL, in the context of adns
-----------------------------------
-Several people have asked me to release adns under the GNU Lesser
+Several people have asked me to release GNU adns under the GNU Lesser
General Public Licence (LGPL, formerly the Library GPL) instead of the
`stronger' GPL. This file is intended to answer most of these
questions. If you still have questions or comments, please mail me at
<adns-maint@chiark.greenend.org.uk>.
Typically there are two or three kinds of situation where people make
-this request: the first is where someone is developing a proprietary
-program and wishes to make use of adns but doesn't wish to make their
-program free software. The second case is where a free software
-project is currently using an MIT-like licence and fear `GPL
-infection'. The third case, which often overlaps with the second, is
-where another free software project currently using a GPL-incompatible
-licence, wishes to use adns.
+this request: the first is where another free software project
+currently using a GPL-incompatible licence, wishes to use adns. The
+second case, which often overlaps with the first, is where a free
+software project is currently using an MIT-like licence or the LGPL
+and fear `GPL infection'. The third case is where someone is
+developing a proprietary program and wishes to make use of adns but
+doesn't wish to make their program free software
-1. Proprietary applications of adns
------------------------------------
-
-So, let me get this straight. You're writing a proprietary
-program, by which I mean that you will not be distributing source code
-and not allowing users to modify and share your software; most likely
-you are doing this for your own (personal or corporate) financial
-gain.
+1. GPL-incompatible free software licences
+------------------------------------------
-However, you want to take advantage of adns, software which I have
-spent my time and effort on, and which I release as free software so
-that everyone can improve, share and use it.
+Regrettably, there are a number of free software licences (and
+semi-free licences) in existence which are not compatible with the
+GPL. That is, they impose restrictions which are not present in the
+GPL, and therefore distributing a whole work which contains both such
+a program and a GPL'd program is not possible: either the combination
+would have to be distributed under the GPL (violating the restrictions
+made by the original author), or under the GPL-incompatible licence
+(violating the GPL).
-Don't you think that is a little hypocritical ? I'm sorry, but I
-don't want you to just take my nice convenient software, without
-giving something back to the free software community or giving the
-same rights to your users as I do to you.
+I may be prepared to make exceptions for such a licence. Please
+contact me at <adns-maint@chiark.greenend.org.uk> with the full text
+of the GPL-incompatible licence. However, I would usually prefer it
+if you could use a GPL-compatible licence for your project instead.
-If you really aren't the nasty kind of person I've described here, for
-example if you have a good reason other than your own selfishness for
-wanting to restrict distribution of your program, then perhaps you
-should contact me to discuss it.
+I have already issued some waivers for certain projects. These are
+reproduced in LICENCE.WAIVERS.
2. GPL-avoiding projects (MIT licence, et al)
Some free software projects prefer to avoid the GPL and other licences
which force the software always to be free. Instead they use
something like the MIT X licence, which allows proprietary versions of
-their software. I have to say that I don't understand why they do
-this, and think they are misguided, but that doesn't mean that they
-don't have a perfect right to.
+their software, or the in the case of some free libraries, the LGPL,
+which allows proprietary applications. I have to say that I think
+these people are misguided, but that doesn't mean that they don't have
+a perfect right to do that.
Some of these people think that merely writing to an interface
provided by GPL'd software will cause their program to become GPL'd
too, even if they don't distribute the GPL'd software. I don't think
-this is the case. I'm perfectly happy for non-GPL'd software to refer
-to adns in its source code or executables (eg, dynamic linking).
-However, if you distribute adns yourself then whether a program which
-uses it needs also to be GPL'd depends on the interpretation of the
-`work as a whole' and `mere aggregation' parts of the GPL.
-
-Whether you are distributing a `work as a whole' might depend on many
-things, but they key one to me is what the appearance is to a user.
-If the user knows that they are getting a collection of software
-rather than a single product, then it's probably an aggregation which
-works together. So, you can distribute both your (i) non-GPLd program
-source and/or binaries and (ii) adns source code or even binaries
-(provided the adns source is available as per the GPL), eg from your
-website, provided the user can tell that these are separate works and
-can tell which parts are which.
-
-But, if you package your program and adns together so that the user is
-no longer aware of adns as a separate work, then I think you are
-distributing a `work as a whole', and the whole work including adns
-and your software which depends on it must be GPL'd. This is of
-course not a problem if your non-GPL licence is GPL-compatible (see
-the next section): it just means that _when the whole lot is shipped
-together as one work_ it is covered by the GPL. People who wish to
-make proprietary works based on just your code can do so, provided
-they (or you) arrange for something to fill the hole left by the lack
-of adns.
-
-
-3. GPL-incompatible free software licences
-------------------------------------------
-
-Regrettably, there are a number of free software licences (and
-semi-free licences) in existence which are not compatible with the
-GPL. That is, they impose restrictions which are not present in the
-GPL, and therefore distributing a whole work which contains such a
-program and a GPL'd program is not possible: either the work would
-have to be distributed under the GPL (violating the restrictions made
-by the original author), or under the GPL-incompatible licence
-(violating the GPL).
-
-I may be prepared to make exceptions for such a licence. Please
-contact me at <adns-maint@chiark.greenend.org.uk> with the full text
-of the GPL-incompatible licence. However, I would prefer it if you
-could use a GPL-compatible licence for your project instead.
-
-There are a couple of common extra restrictions, and I make some
-specific extensions to my licence for adns below.
-
-3.1. BSD advertising clause and endorsement restriction
-
-The most notable and common extra restriction found in free software
-licences is the `obnoxious BSD advertising clause' (see Richard
-Stallman's article on the subject, available from www.gnu.org) and the
-endorsement restriction.
-
-The problem with the advertising clause isn't that the sentence
-required, referring the the Regents of the UC Berkeley, is awkward.
-The problem is that if everyone contributing to a large project gets
-such a mention the number of sentences required becomes very large;
-however, it is unfair for some people to get credit and others not to.
-
-I disapprove of these clause, but I recognise that it may be difficult
-for some people to get them removed from particular programs.
-
-So, I hereby make an extension to my licence for adns:
-
- You may alternatively distribute adns under the GNU GPL version 2
- with the following banner and either one or both of the following
- additional restrictions, to be inserted at the end of section 1:
-
- ADDITIONAL RESTRICTIONS:
- (The permissions granted in this licence only apply if you comply
- with the following restrictions:)
-
- (a) All advertising materials mentioning features or use of the Program
- (or a work based on the Program, GPL section 2) must display the
- following acknowledgement for each author, copyright holder or
- group of authors or copyright holders:
-
- This product includes software developed by PERSON OR GROUP.
+this is the case. I'm perfectly happy for non-GPL'd but
+GPL-compatible software to refer to adns in its source code. However,
+I think that exectuables (or compiled libraries) which contain or are
+dynamically linked against adns must be GPL'd; likewise executable
+programs (whether compiled or in an interpreted language) which
+require utilities from adns to function properly must be GPL'd.
+
+So, you can distribute your non-GPL'd program source which needs adns
+to compile (provided it's under a GPL-compatible licence), but people
+who wish to distribute binaries must do so under the terms of the GNU
+GPL. This may make sense for some GPL-avoiding free software
+projects; people can still make proprietary programs from your code,
+provided that they make some provision to replace adns with something
+whose copyright allows proprietary versions.
+
+However, this doesn't make much sense for the authors of LGPL'd
+libraries. All I can say to them is to ask which is more important:
+that their library be well-constructed and use all the best technology
+available as free software, or whether it is worth degrading quality
+of their library in order to allow proprietary programs to use it !
+
+To help the case of LGPL'd libraries for which adns is not a vital
+component - for example, a library which provides access to other
+libraries so that programs which use it need only use certain parts,
+I have released adns.h (just the public header file) under the LGPL as
+well as the GPL. See the copyright notice in adns.h for details.
+Note that this will not help you if it adns is essential to the
+functioning of your library, because all programs using your library
+must link against both your library and adns and so must be GPL'd.
+
+
+For some information and views from the Free Software Foundation on
+free software licensing, visit:
+
+ Various licenses and comments about them
+ at http://www.fsf.org/philosophy/license-list.html
+
+ Why you shouldn't use the Library GPL for your next library
+ at http://www.fsf.org/philosophy/why-not-lgpl.html
+
+
+3. Proprietary applications of adns
+-----------------------------------
- where PERSON OR GROUP is the name of the (group of) authors or
- copyright holders, in the form in which they reasonably wish
- themselves to be identified in such acknowledgements. A
- reasonable alternative form of words must be used if requested
- by the person or group.
+This applies to you if you are writing a proprietary program, by which
+I mean that you will not be distributing source code and not allowing
+users to modify and share your software; most likely you are doing
+this for your own (personal or corporate) financial gain.
- The desires of the persons or groups are to be inferred from
- statements made about the desired form of such acknowledgements
- by these persons or groups in their own copyright notices and
- licences. Such statements are to be considered part of the
- appropriate copyright notice that the GPL requires you to
- publish (section 1).
+In this case the copyleft GPL licence does not meet your needs.
+Instead, you will need to negotiate a separate proprietary licence for
+adns.
- This credit must be given for every author and copyright holder
- of the Program or the work based on the Program, in so far as it
- reasonably possible to determine who the author(s) and copyright
- holder(s) are.
+The List Price for a proprietary but LGPL-compatible application which
+uses adns is EUR150,000 per program per 10,000 users or part thereof,
+of which I will donate 25% to a Free Software organisation of my
+choice (as recognition for the contributions and help I have received
+from the Free Software communicy).
- (b) None of the names of the copyright holders and authors of the
- Program or works based on the Program may be used to endorse or
- promote the Program or works based on the Program without
- specific prior written permission.
+Discounts may be available, particularly if I approve of your product.
+So, if you are serious about proprietary software, and paying for the
+software that you use, please contact me to negotiate a good deal.
- Any rephrasing of this restriction provided by authors or
- copyright holders in their copyright notices is to be retained
- as part of the appropriate copyright notice that the GPL
- requires you to publish (section 1).
+-- Ian Jackson 22.5.2004
---- Ian Jackson 9.5.1999
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