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Re: Linux and GPLv2

On Wed, 23 Mar 2005 10:49:34 +0100 (MET) Gerardo Ballabio wrote:

> > From: Francesco Poli <frx@firenze.linux.it>
> > I don't think it's forbidding to remove the code: it's merely  
> > forbidding to drop a feature.
> > You could reimplement it in a better (or even worse) way, but you  
> > must support it.
> Then if my reimplementation has a bug that prevents it from working  
> properly, I may be accused of infringement?

I don't know (IANAL). Maybe if it can be proved that your
reimplementation is intentionally buggy.
But I repeat: I don't really know...

> > Anyway I agree it's non-free.
> Then you may be surprised to hear that the GPLv2 does have a "don't  
> remove this feature" clause:

Well, I was aware of that clause (even though maybe I was not thinking
about it, while discussing the "get the source through HTTP" feature and
its corresponding "do not drop this feature" clause...).

> c) If the modified program normally reads commands interactively
> when run, you must cause it, when started running for such
> interactive use in the most ordinary way, to print or display an
> announcement including an appropriate copyright notice and a
> notice that there is no warranty (or else, saying that you provide
> a warranty) and that users may redistribute the program under
> these conditions, and telling the user how to view a copy of this
> License.  (Exception: if the Program itself is interactive but
> does not normally print such an announcement, your work based on
> the Program is not required to print an announcement.)

This clause is known to be controversial.
I would be happier if it were not present at all in the GNU GPL...
I'm not sure, but my mind seems to recall to have read a statement from
the FSF itself recommending against abusing this clause: but, after
searching for such a statement for a while, I failed to find it and gave
up...  :(

However it's some orders of magnitude less demanding than the "do not
drop the get-the-source-through-HTTP feature" clause, I would say.
Printing one or two statements to stdout or in a splash screen is really
really easier than implementing (or keeping) HTTP support and the
capability to send the program's own source.

I think that clause 2c of GPLv2 is really borderline with respect to
DFSG-freeness, but judging whether it's on one side or on the other one
is not easy.
On the one hand, it resembles to an acceptable requirement to include
copyright notices and warranty disclaimers.
On the other hand, it's a functional constraint, though a very little

> I'd even read this as saying "if the original program isn't  
> interactive, but the modified one is, you must _add_ that feature".

I had never noticed that, I must admit!  :-(
But reading and re-reading the clause seems to bring me to same
And this is a little worrysome...

    :-(   This Universe is buggy! Where's the Creator's BTS?   ;-)
  Francesco Poli                             GnuPG Key ID = DD6DFCF4
 Key fingerprint = C979 F34B 27CE 5CD8 DC12  31B5 78F4 279B DD6D FCF4

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