about LGPL - practical aspects

[Vadim Plessky]

David Turner, of FreeType fame (http://www.freetype.org), made very 
interesting comments on LGPL - see below.
It's (partially) in reply to Paul Pedriano's question.

in short, David writes that " LGPL is not friendly to embedded systems"
Do we want KDE to be suitable for Embedded market?
Than we should think about licensing for kdelibs, etc. from the beginning. Or, 
at least, address possible issues from now and later.

Cheers,

Vadim

----------  Forwarded Message  ----------

Subject: Re: [Freetype] Where can I find a decent introduction to text layout?
Date: Saturday 23 November 2002 8:28 pm
From: David Turner <david@freetype.org>
To: freetype@freetype.org

Vadim Plessky wrote:
> On Saturday 23 November 2002 12:35 am, Pedriana, Paul wrote:
> [...]
>
> |     >>There is also Pango, which is LGPL-ed and thus
> |     >>probably unusable on the PlayStation and GameCube.
> |
> |  LGPL software is completely out of the question. The LGPL,
> |  regardless of any intentions the authors may have had, makes
> |  many corporate lawyers run screaming in the opposite direction.
>
> I am curious to know what frustrates corporate lawyers in LGPL.
> LGPL is *not* GPL!

Note: I'm not responding for Paul, just giving my point of view.
His, or his company's, might be different.

Have you ever read the LGPL in details. It contains so many
ambiguous clauses that this even makes lawyers scared :-)

It's very difficult to determine exactly what the LGPL allows when
it comes to embedded systems. The problem revolves around the
idea of "dynamic linking" or "relinking" that is not possible
when your code is in ROM, or directly run from a CD or cartridge.

There are, to my knowledge, two distinct interpretation of the
"clause":

   - one interpretation simply says that you simply cannot
     put LGPL-ed code in ROM/Cartridges/etc... (think
     PlayStation/GameCubes)

   - the other, twisted, interpretation is that you can ship
     products with LGPL code in ROM, as long as you also provide
     to those users who ask for it, the object files needed to
     re-link, even statically, the binaries !!

     yes, that seems stupid, since you cannot change what is
     in ROM anyway, but that's the interpretation that several
     person gave me to explain why they could freely use
     LGPL-ed code in products based on embedded OSes
     that run programs directly from ROM/Flash


Because of these ambiguities, lawyers hate to deal with LGPL
libraries when they have a choice to.

I believe that the base idea is that if a program uses LGPL-ed
code, a normal user should be able to relink the program with
a newer version of the library when he wants to. Of course,
this is not possible when you only provide a statically linked
executable. Funnily, being able to re-link doesn't mean being
able to use the new code !!

In all cases, the LGPL is not friendly to embedded systems. That's
why certain people release their open-source code under a special
license, called the "GPL with exception".

Speficially, this says that:

    - the source code is released under the GPL.

    - but the copyright owner also grants you an *additional*
      right, which is to produce a *stand-alone* *executable*
      freely (i.e. without the GPL applying to it) with the
      sources that *he* distributes.

It's a sort of dual-licensing option. Basically:

   - you can create proprietary products with this code, as
     long as you don't modify it !!

   - if you modify the code, the GPL applies to your sources
     (i.e. *all* of your source falls under its license),
     *without* the exception.

you're then forced to send your changes to the original
author, because he's the only person that is capable of
releasing the new sources under the "GPL + exception" license
that you can use to build products freely.

(Of course, this generally involves assigning the copyright of
  your changes to the author as well).

It's used by quite a number of succesful project in the embedded
world. Maybe we'll switch to it one day :-)

> BTW:  is BSD ok for you?

Given that they seem to use FreeType, I suppose yes :o)

Cheers,

- David Turner
- The FreeType Project  (www.freetype.org)


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Vadim Plessky
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