Re: why LGPL 2.0?

[Owen Taylor <otaylor redhat com>]

On Thu, 2003-05-01 at 18:21, Joseph J. Strout wrote:
> I'm currently trying to convince my company to base its next major 
> project on GTK++.  But they're nervous about the licensing issues 
> (this will be a commercial product).

I'm not aware of a library called "GTK++" ... are you talking
about GTK+? :-)

> Part of this is caused by the fact that GTK++ comes with LGPL version 
> 2, from June 1991.  This has some very confusing wording in section 
> 5, where the first paragraph says that a program that links with the 
> library is not a derivative work, and the second paragraph says that 
> a program that links with the library IS a derivative work.
>
> I notice that the current version of LGPL at gnu.org is Version 2.1, 
> from February 1999.  This has slightly clearer wording in section 5 
> (though it still contains this apparent contradiction).  Any chance 
> the copyright holders of the GTK++ code would consider updating to 
> that version of the license?

 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.

That is included in the license statement for all GTK+ source
files, so if you feel that the LGPL 2.1 is clearer, you can
consider it to be the license.

> Also, if our attorney needs a written statement of approval from 
> someone clarifying that our intended use of GTK++ does not constitute 
> a derivative work, whom would we talk to about that?

I'm willing to give a statement of *my understanding* of the
LGPL, and I'm one of the primary maintainers, and have contributed
a large portion of the code; if you think that it useful,
get in touch with me privately.

But unfortunately, I can't:

 - Give a legally binding position on behalf of all copyright holders
   for GTK+.

 - Give a legally informed position; I'm not a lawyer.

I think there is a common sense, simple, interpretation of the LGPL 
that is generally agreed upon; in two items:
  
 - If you distribute binaries for GTK+, you must distribute (or
   make available) the source to it and all modifications
   you make to them.
 - You must distribute your application in such a way that
   users can modify the GTK+ sources, recompile them and
   use your app with the modified sources.

If you stick to the above, I'd consider it very well
understood and safe. Major vendors such as IBM and Oracle
rely on this interpretation when they distribute code
linked against the Linux C library.

This covers most usages; there are some things which are less
clear; for instance, modifying GTK+ in such a way that it
requires a proprietary library, or using GTK+ in a device where
the code is burned into ROM, where the situation is not 
as clear; but these shouldn't affect most commercial uses.

Regards,
                                            Owen