[License-discuss] Differences between GPL and LGPL

Engel Nyst engel.nyst at gmail.com
Thu Jan 3 12:47:20 UTC 2013

Hello license-discuss,


Thank you very much for the discussion on the actual differences
between GPL and LGPL in practice! Your clarifications on common
misunderstandings on GPL/LGPL would be extremely welcome for me, and
IMHO they are needed.

Please do consider that apart the groups hinted at, companies which
'force disclosure' of source code and companies which 'choose GPL over
LGPL to force disclosure', there are Open Source projects and
developers which might be interested in the questions. I know I am.

Unfortunately I'm sure that between a common (mis)understanding of
GPL/LGPL and correct use of the legal terms here, there is a mismatch,
which makes it difficult to express what one wants to say without
risking to use the terms inappropriately.

I will take the chance to do so nevertheless.

> You keep referring to the enormous cost of litigation and you encourage
> companies to err on the "conservative side" of this GPL/LGPL issue. You
> should also consider the potential cost to a plaintiff for falsely accusing
> a defendant of copyright infringement, even outside of court. I would also
> like you to weigh the frustrated expectations of licensors who choose
> between the GPL and LGPL on mistaken grounds, expecting certain behavior by
> their licensees that they won't be able to force even in a court fight.

If I use an LGPL software in my application, without modifying its
code in any way, it's probably safe to say I can license my code in
any way. Including what is declared as GPL-incompatible licenses for
the rest of the code.

If I use GPL software in my application, then almost no matter what
does my application do, if it's on a single computer (classical
scenario), then the whole will have to be at least relicensable as
GPL. (at least relicensable, if I don't have to even relicense it
myself). That's either possible and wanted, or it's not: my project
may have GPL-incompatible pieces, it may be driven by a copyleft
policy under a license which FSF declares GPL-incompatible, or it may
be permissive and want to remain that way.

I don't even get to the question: do I intend to create a 'derivative
work under US copyright law': I have an answer cut out for me before
even getting there. This answer comes from the perception of GPL
intentions, at least, and for sure perception of FSF's explanations.

Strangely, this way I can relate to Bruce's expression "to err on the
conservative side". This has nothing to do with business and
proprietary licensing, and only with my perception of what can
possibly be done when combining FOSS licenses.

Apart from this, it's however true that it has always been my
perception that "derivative work" is indeed redefined by GPL in
practice at least, if not explicitly...

> FOSS is no longer a small-business enterprise where a random copyright owner
> can threaten licensees to force the disclosure of proprietary code and
> expect to win simply because of community pressure. (At the very least, you
> shouldn't expect open source lawyers like me to respond to that form of
> community pressure on a list like this!)

Alternative perspective, if I may: I don't want an Open Source project
I contribute to, to break the expectations and intentions of another
Open Source project which uses GPL. Not for 'fear of litigation'. But
I guarantee to a community that the code is Open Source and safe to
use, modify, and share, as they receive it, under the terms of the
respective license(s), and does not break anyone's rights, nor did
independently written code become GPL without explicit relicensing and
appropriate community discussion.


I apologize for the off-topic. Better understanding of GPL/LGPL has,
to me, more to do with license compatibility, though, than flamewars,
even if some of the issues are very prone to the latter. I understand
if people feel differently, though, and I apologize if this message is
an unfortunate part of it.

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