Re: why LGPL 2.0?

[Douglas Ian Linder <linderdi cs curtin edu au>]

All I can say is, let me clarify what I've written as:

This is my oppinion and I'm not a lawyer, BUT I have had a friend 
who is a law student look at it for me, and that's what he said.

On Fri, 2 May 2003, Paul Davis wrote:

> >      So...? Basically, under section (5) you're screwed. If you link
> >      with the GTK stuff, you form a derivative of the library and must
> >      release the source code, EVEN THOUGH the source code itself is
> >      not, when independent of the library, covered by the license.
> 
> AFAIK, this is absolutely and completely untrue.

Yes, because of section 6. However, UPTO section 5, the above it true.
No, it's not true about the entire license, but if you consider the 
license up to that point:

(1) - The executable is a derivative work.
(2) - Derivative works require full release of source (see section 2)

Then you move onto section 6 which provides the exceptions that make
LGPL different to the GPL...

> the entire point of the LGPL is that you do *not* have to distribute
> your source. what you have to do is to distribute your program in a
> way that makes it possible for the user to relink against a modified
> version of the library in question.

Um...yeah. Kinda. Let me just state, based on the license, do NOT
think that releasing software under LGPL simply implies you do
not need to release your source code.

There is a certain sub-set of cases in which releasing the source
code is not required. This is the case in which your program is a
"work that uses the library", and as such although a derivative of
the library, does NOT require the release of source code. Any other
program under LGPL requires the release of source code. Any update 
to a program under LGPL requires the release of source code.

I'll point your attention to section 2 for this. This section
is like the pure GPL section 2.

> typically, you'd give the user a big .o file, maybe (or maybe not)
> some instructions on how to link it, and thats that.

As I said, for a set of cases, sure. Release the .o files. You don't
even have to do that in some cases. This would probably be the case
of what you would do if you statically linked the library to your
application. 

> you do not ever ever ever have to release source code to your
> program. if you did, there would be no point to the LGPL.
 
Indeed. There are some who argue the LGPL is too restrictive and not
really what it was set out to be, and I'll point out that LGPL is NOT 
the magic use-free-stuff-in-commerical-products magic blanket that some 
people seem to think it is. Like any other license agreement, it has terms 
and conditions that need to be considered. Section 5 and 6 simply make it 
a bit more flexible than the pure GPL.

> as you noted, none of this matters if you use dynamic/shared/run-time
> linking against the library, because the user is automatically
> "relinking" against whatever version of the library they have every
> time they run the program.

However, note the requirements for the terms and conditions of the
work released. If you release a product that does not satisfy 
the "...terms permit modification of the work..." blah you are in 
breach, and I'll just point you to section 11. If you are in breach
you may not distribute the library.

The library. 

That is, YOUR derivative work, the application using the library,
may not be distributed if it is in breach. I doubt you'd be ordered
to do a recall based on this, but it's not impossible.

"The LGPL does not require to release source code, otherwise it'd be 
pointless." All I'm going to say to finish up is, this is serious stuff. 

Nothing I've said is technically legal advice. If you plan to use LGPL
in a commercial product:

(1) - Yes, it is possible to do this, with certain restrictions on
      the terms, but release of source code is not required.

(2) - Get your legal department to examine the license (or you don't have 
      one seek external legal advice on it). 

It's not that complicated, but it DOES have ramifications when used,
and you MUST be aware of them when using the license. 

ciao!
Doug.