Re: [Help-glpk] Command-line and GPL

[Paul Mars]

I guess this is covered in the FAQ at the GNU.org web site at
http://www.gnu.org/licenses/gpl-faq.html#GPLInProprietarySystem

[quote]

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.

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.

If people were to distribute GPL-covered software calling it "part of" a 
system that users know is partly proprietary, users might be uncertain of 
their rights regarding the GPL-covered software. But if they know that what 
they have received is a free program plus another program, side by side, 
their rights will be clear.

[/quote]

----- Original Message ----- 
From: "Andrew Makhorin" <address@hidden>
To: "Meketon, Marc" <address@hidden>
Cc: <address@hidden>
Sent: Saturday, June 23, 2007 2:16 AM
Subject: Re: [Help-glpk] Command-line and GPL


>> People build commercial applications all the time under Linux.  These
>> applications implicitly call the Linux kernel, and perhaps explicitly
>> call on a variety of commands (which are really applications) like "mv",
>> "cp" and so on.  Yet these commercial applications are not under the
>> GPL.  I think Luca's situation is similar.
>
> I do not think so. Commercial software does not mean non-free (i.e.
> proprietary) software. On the other hand, if someone does not want to
> make his software free, he is free to make it non-free. However, in
> this case it would be fair not to use free software at all, wouldn't
> be? It seems to me this is the main point of GPL. (Sorry for my bad
> English.)
>
>
>
>
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