Subject: Re: license-mix, legal consequences?
From: Danese Cooper <Danese.Cooper@Sun.COM>
Date: Tue, 19 Jun 2001 12:45:01 -0700

At Sun, we license code under both the LGPL and SISSL.
Since only the copyright holder can change licensing terms for a body 
of code, we collect copyright assignments from contributors (whether 
they are working under LGPL or SISSL).  The point is that we have to 
work at keeping the codebase "whole" under both licenses.

About including code you don't "own" (by copyright) in such a scheme.  In 
NetBeans there were several libraries which we didn't own and didn't have 
rights to redistribute.  We included these as binaries with the author's 
permission and modified our build system to use the binaries...


>on Sun, Jun 17, 2001 at 08:38:55AM -0300, Henningsen ( wrote:
>> I want to release code I write myself under a dual license scheme,
>> both GPL and commercial license, the latter for people who want to use
>> the code in closed source projects. In my project I would like to
>> include code released under the Tcl/Tk license model ("keep copyright
>> notices in place, and keep this license text with the code"), and code
>> released under the MIT license. 
>> I checked on the FSF's site whether these licenses are compatible with
>> the GPL, and didn't find anything. Are they or are they not? And if
>> they're not, would that mean that people who want to use my
>> GPL-released code could not also use the code modules with
>> incompatible licenses unless they got a special permission from me (in
>> effect a free commercial license)?
>First, IANAL.
>Dual licensing of your own code doesn't (generally) require
>"compatibility" between licenses, defined as the ability for software
>under one license to be used under the terms of another.  
>This is effectively a logical OR:  compatibility requires that,
>excepting other arrangements with the copyright holder(s), you can use
>alternative or additional licensing terms.  This is a small set of
>Dual (or multiple) licensing, on the other hand, is a logical AND.
>You're saying that any of the specified licenses is sufficient to meet
>the legal obligations for software copying, modification, distribution,
>or other 17 USC (or Berne, internationally) exclusive rights under
>The issue that may then arise is the introduction of third-party code
>into your project.  So long as this code is introduced under the same
>dual/multi license terms, there are no compatibility issues raised.
>However, if code is contributed under only one, or some other subset, of
>licenses, the codebase as a whole becomes restricted as to which
>portions can be used under what terms under altnernative licensing
>As an example, I do work under Python.  Until now, Python has been
>licensed under terms similar to the BSD/MIT license.  Last week, Guido
>van Rossum announced that license compatibility with the GNU GPL had
>been achieved.  I would prefer to license my own code under the
>GPL/LGPL, and preferably no other terms.  This could create a conflict
>for those who are using Python in, say, proprietary applications, but
>would then have to determine whether or not they could incorporate code
>authored by me, and/or under what terms.
>Multiple licensing is an interesting hack, but it's not without its own
>set of additional issues as well.
>In your own case, my general understanding is that the MIT and Tcl/Tk
>licenses should be compatible. 
>I'd be interested in other viewpoints on this.
>Karsten M. Self <>
> What part of "Gestalt" don't you understand?       There is no K5 cabal
>   Are these opinions my employer's?  Hah!  I don't believe them myself!