Re: GPL again (was IFS in RPG)

["John Taylor" <jtaylor@xxxxxxxxxxxx>]

Hi Buck,


> As you know, I work for a software vendor.  I've spoken with a few Open
> Source GPL developers, and while this does not constitute legal advice, it
> should count for something...

Unfortunately, it counts for nothing. Mainly because there seems to be
considerable confusion amongst developers -- myself included -- with respect
to how the GPL really works. Even the good folks at GNU allow that what it
ultimately means will be determined by judges:

Q. What is the difference between "mere aggregation" and "combining two
modules into one program"?

A. (only relevent parts included, for brevity)  Combining two modules means
connecting them together so that they form a single larger program. If
either part is covered by the GPL, the whole combination must also be
released under the GPL--if you can't, or won't, do that, you may not combine
them.
What constitutes combining two parts into one program? This is a legal
question, which ultimately judges will decide. We believe that a proper
criterion depends both on the mechanism of communication (exec, pipes, rpc,
function calls within a shared address space, etc.) and the semantics of the
communication (what kinds of information are interchanged).

If the modules are included in the same executable file, they are definitely
combined in one program. If modules are designed to run linked together in a
shared address space, that almost surely means combining them into one
program.

>  If I understand the state of affairs properly
> (enough disclaimers yet?) I can NOT use the source of a GPL project in my
> package.  I CAN have programs in my package make calls to procedures in
the
> GPL package.  I can NOT include the binaries of a GPL project with the
> distribution of my package.  I CAN distribute instructions to my customers
> on how to acquire and load the GPL package.

Then let me offer another excerpt from the GPL FAQ at gnu.org:

Q. I'd like to incorporate GPL-covered software in my proprietary system.
Can I do this?

A. You cannot incorporate GPL-covered software in a proprietary system. The
goal of the GPL is to grant everyone the freedom to copy, redistribute,
understand, and modify a program. If you could incorporate GPL-covered
software into a non-free system, it would have the effect of making the
GPL-covered software non-free too.
A system incorporating a GPL-covered program is an extended version of that
program. The GPL says that any extended version of the program must be
released under the GPL if it is released at all. This is for two reasons: to
make sure that users who get the software get the freedom they should have,
and to encourage people to give back improvements that they make.

* The answer goes on to address what you've suggested, as follows:

However, in many cases you can distribute the GPL-covered software alongside
your proprietary system. To do this validly, you must make sure that the
free and non-free programs communicate at arms length, that they are not
combined in a way that would make them effectively a single program.

The difference between this and "incorporating" the GPL-covered software is
partly a matter of substance and partly form. The substantive part is this:
if the two programs are combined so that they become effectively two parts
of one program, then you can't treat them as two separate programs. So the
GPL has to cover the whole thing.

If the two programs remain well separated, like the compiler and the kernel,
or like an editor and a shell, then you can treat them as two separate
programs--but you have to do it properly. The issue is simply one of form:
how you describe what you are doing. Why do we care about this? Because we
want to make sure the users clearly understand the free status of the
GPL-covered software in the collection.

> In short, I can add the hooks from me to the GPL package as long as I let
my
> customers acquire the package.  If I do it this way, my package is NOT
GPL.
> It's a pain, for sure.
>
> That's the way I understand it.

I respectfully disagree. Ultimately, it's the courts that will decide these
issues, but who among us is willing to bet the farm that the decision works
in our favour?


John Taylor