[sane-devel] Please give me some help to solve the license issues in using sane

[Olaf Meeuwissen]

Johannes Meixner <jsmeix at suse.de> writes:

> Hello,
>
> On Jun 6 16:40 Alessandro Zummo wrote (shortened):
>> http://www.gnu.org/licenses/gpl-faq.html#FSWithNFLibs
>
> As far as I see, it seems to be allowed from the legal point
> of view to have free software that uses non-free libraries
> because they only say that the program won't be fully usable
> or not usable at all in a free environment but they don't
> say it violates the GPL.

This depends on the respective license conditions of the free and
non-free parts.  If all of the conditions are not mutually exclusive,
then there is no problem license wise.  If even only two of the
conditions are mutually exclusive, you have a license violation on
your hands.

The above goes for any kind of combination where multiple licenses are
involved, not just when combining with GPL'd software.

> But what does "If it depends on a non-free library to run at all,
> it cannot be part of a free operating system such as GNU" mean?
>
> Is "cannot be part of GNU" meant as a license violation or
> just that it cannot be included in a "free operating system"
> simply because it is useless?

The latter.  If something that requires non-free parts to operate were
added to a free operating system, that operating system automatically
becomes non-free.  Please remember, the GNU project takes freedom
seriously.  If there is one REQUIRED non-free component, the whole
thing is no longer free.  Any free operating system needs to be 100%
free.  Anything less would simply not be free.

> But why can't there be a program in a "free operating system"
> which requires a proprietary library which checks if the
> library file is there before it dlopens it and if the library
> file is not installed, it shows a message where to get it
> (e.g. where to download it - or perhaps it even runs a
> download user GUI with appropriate license information).

If said program would be free-as-in-freedom, that program could be
part of a free operating system, license wise.  However, as it exists
solely to allow the user to make their operating system non-free, it
is very likely to attract a fair bunch of flac from the die-hard free
software corners.

> For example a GPL media player which supports only a proprietary
> media format.

GNU folks will write a free library to support the media format (as
they do with gnash, a free flash player) or advocate alternative, free
formats (as they do with ogg/vorbis).

> Such a program would be even useful without the proprietary library
> installed because it would show the user a message where to get the
> missing part.  Of course the proprietary library might be not
> available for all hardware architectures but this does not mean that
> such a GPL media player is useless in any case.  Of course all
> proprietary media formats and all proprietary device communication
> protocols are against the intention of a "Free World" but this does
> not mean that programs for such formats/protocols are useless.

If the only use of the program is telling the user how to sacrifice
one's freedom in the interest of convenience, the program is not
useful in a GNU world.  Quite on the contrary, it is decidedly
counter-productive to the GNU project's cause.

> They even say:
> ---------------------------------------------------------------
> If the program is already written using the non-free library,
> perhaps it is too late to change the decision. You may as well
> release the program as it stands, rather than not release it. 
> ---------------------------------------------------------------

So others can take a look at replacing the non-free components and
benefit from the effort that went into writing the rest of the
program?

> This seems to indicate that free software that uses non-free
> libraries is in compliance with the GPL from the legal point
> of view.

IF AND ONLY IF the license conditions of all the parts involved are
not mutually exclusive.  Please refrain from making such unqualified
statements.  They are misleading.

In general, the combination of GPL'd software with non-free libraries
results in mutually exclusive license conditions.  That's why the
library gets labelled non-free in the first place.  Only if the
license conditions of the GPL'd parts are changed to add exceptions
enabling use with the non-free library can you resolve the mutually
exclusive conditions.  Once you do that, the GPL'd parts are no longer
GPL.  They become GPL + exception.  The GNU Coding Standards[1] even
mention some notation in the section on the --version option[2] where
they list GPL/Guile and GPL/Ada.

 [1] http://www.gnu.org/software/automake/manual/standards.html
 [2] http://www.gnu.org/software/automake/manual/standards.html#g_t_002d_002dversion

> Of course this is only what I perceive right now from what
> I read there and of course I am not a lawyer!

Hope this helps,
-- 
Olaf Meeuwissen                   FLOSS Engineer -- AVASYS Corporation
FSF Associate Member #1962           sign up at http://member.fsf.org/