Re: amber-developers: "open source" and GPL software

From: Lance Westerhoff <>
Date: Thu, 8 May 2008 08:57:59 -0400


I deal with licenses pretty often, so I figured I would switch off
lurker mode for the moment and comment.

On May 7, 2008, at 10:23 PM, Ross Walker wrote:

>> No, this would not be acceptable. See section 2b of the GPL
>> license:
>> b) You must cause any work that you distribute or publish, that in
>> whole or in part contains or is derived from the Program or any
>> part thereof, to be licensed as a whole at no charge to all third
>> parties under the terms of this License.
>> Roughly: If your code links to a GPL routine, and you want to
>> distribute
>> your code, you must distribute the entire code under the GPL.
> But as far as I can tell just about everything that runs on Linux is
> in
> breach of this license model. Is not most of the stuff in Linux GPL?
> If so
> then building any commercial software on Linux would breach this
> license
> since just linking against various system libraries statically
> would put
> you in breach of this. And what about dynamic linking?
> Note FFTW is released under GPL so does this mean everything that
> links
> against it that is not GPL is in breach of the GPL license?
> Surely we just build any GPL software we want to use as a library
> and link
> against it no? This appears to be what everyone else does.

Ross, most (not all) of the libraries that linux come with are
licensed under LGPL (not GPL). L stands for Lesser (or Library in
some circles). It is considered "Lesser" because it is less
restrictive. Basically, the LGPL allows both open and closed source
to link against it without trouble. The developer who adds souce
directly to a LGPL library must opensource that code. However, a
developer who simply dynamically links against the library, is free to
do whatever he wants with his code. It gets a bit more hairy (I
think) with static linking. But I don't think anyone has ever been
"called" on static linking.

GPL isn't like that. GPL would require the developer to opensource
their code regardless of whether or not the code was added directly to
the library OR linked against the library.

So LGPL code (just like BSD and some others) are just fine for closed
source apps so inclusion of software like MTK++ and the like are
acceptable. In fact, if you build the software on Linux chances are
you are already linking against LGPL code and you may not know it.
Many mainstream Linux vendors try to use LGPL (almost) exclusively
just so people don't have to worry about this license issue.

As an example of the fun that can be had with licenses: Qt (the basis
of KDE) is licensed under GPL however gtk+ (the basis of GNOME) is
licensed under LGPL. The reason for the difference is Trolltech wants
to sell a product (ie: Qt) to commercial users but they also want the
opensource community to be free to use the software as they may.

Disclaimer: I'm not a lawyer so take what I say with a grain of salt.

Hope that helps!

Lance M. Westerhoff, Ph.D.
General Manager
QuantumBio Inc.


Phone: 814-235-6908
Fax: 814-235-6909
Received on Sun May 11 2008 - 06:07:28 PDT
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