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Re: licensing confusion

On Thu, 04 Mar 2004, Marek Habersack wrote:
> I know it belongs in debian-legal, but I'm not inclined enough to
> join yet another mailing list which I will read few and far between,
> so I will take the liberty to ask my question here.

In cases like these, please set Mail-Followup-To: so you'll be Cc:'ed
as well as the list, and then send the mail to the appropriate
list. [Crossposting to -legal, MFT: set appropriately. Please continue
relevant discussion there.]

> It's simple - how is it possible that most licenses used by free
> software are incompatible [1] with GPL and yet debian mixes them in
> many projects it distributes (like mozilla, php, apache to name the
> most prominent ones). 

Mozilla is (for the most part) dual licensed under the (M|N)PL and

Apache itself doesn't contain any GPL licensed code, and as far as I
am aware, isn't a derivative work of any GPL licensed code.

PHP (to my knowledge) follows along much the same lines as Apache.

Before trotting out examples of incompatibilities (especially ones
that "debian mixes [...] in many projects it distributes"), you need
to walk through why you believe the incompatibility to exist in the
first place. In cases where we discover code that is a derivative work
of a GPLed work that cannot be re-distributed under the GPL, we
scrutinize them very carefully, and often request specific exemptions
from the author of the derivative work so that we can legally
distribute the resultant work.

> What are the rules to freely (as in freedom) use the other licenses
> which are incompatible with GPL and to remain compatible with GPL
> without being forced to use it in your own projects which you don't
> want to license under GPL/LGPL? Does one have to obtain some kind of
> exemption from any of the "sides"?

You (in general) can't incorporate code which is under a license that
is incompatible with the GPL to create a derivative work under the GPL
unless you yourself are the copyright holder of both works in

The general method is to choose licenses carefully so that they are
GPL compatible if you ever want to incorporate them into a GPLed work,
or dual license the work so that you can incorporate them.

In the end, it really depends on what your goals are for the license
and for the work. If you have a concrete example of what you want to
do, we may be able to provide some ideas on what you might want to

Don Armstrong

It seems intuitively obvious to me, which means that it might be wrong
 -- Chris Torek


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