Re: [Chicken-hackers] Re: Backdoor GPL in message-digest

[Peter Bex]

On Tue, Aug 24, 2010 at 12:02:49PM -0400, John Cowan wrote:
> > Also note that the LGPL is incompatible with the GPL in that you cannot
> > link a LGPL library or program to a GPL library(!)
> 
> That's definitely false.  The whole point of the LGPL (2.1 or 3) is that
> you can use an LGPLed library in a program which, as a whole, is under
> almost any license

That's not what I said.  I said you can't link a LGPL library to a GPL
library.  You said you *can* link a GPL library to a LGPL library, which
is of course correct (but the other way around).

This is in FSF's FAQ:
http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL

>From what I understand of it, writing an LGPL library on top of a GPL
library is simply not allowed because that would require the "upper"
library to be GPLed too.  The GPL library forces everything on top of
it to be GPL.

For a practical example, there's MySQL. People have cursed MySQL not
just for being a crappy database but also for the fact that their client
libraries are (or used to be?) GPL.  I couldn't write a mysql Chicken
Scheme egg which binds the MySQL client libraries and release the egg
under LGPL, for instance.

See also http://lists.mysql.com/mysql/155849

> However, it is true that the GPL2 and GPL3 conflict, because the GPL2
> wants the linked binary to be GPL2, whereas the GPL3 wants it to be GPL3.

That's important to catch with chicken-install or salmonella, too.
I think this may be a much more common case in practice than the example
of GPLed libraries.

Cheers,
Peter
-- 
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