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

[Olaf Meeuwissen]

"m. allan noah" <kitno455 at gmail.com> writes:

> [snip]
>>
>>  this means that the sane I/O facilities cannot be used. however
>>   it may be the cleanest thing.
>>
>>   that's similar to the epkowa way, which uses sane io facilities
>>   iirc?
>
> well, if epkowa dynamically links and uses sanei, then it is not using
> #3- it might be violating the license? Olaf- can you describe the
> mechanism?

As anyone can infer from the epkowa sources, it dlopen()s interpreters
and passes two callbacks for USB I/O.  These callbacks ultimately call
the sanei_usb read and write functions.

The fact that epkowa dlopen()s instead of dynamically linking does not
make any difference license wise.  It is a convenience that allows for
the separate distribution of non-free plugins.
# Older versions of the epkowa backend would segfault without them!

Also, the epkowa backend started out life as a clone of the epson
backend (around sane-1.0.3).  As a result, it relies on sanei to take
care of a few things (I/O, config, etc) and most of the epkowa backend
code is licensed under the GPL + SANE exception.  The bits that are
under a (slightly) different license, the epkowa_ip* files, are GPL +
an exception that is more restrictive than the SANE exception.

WRT the possibility of violating the license, you've stated[1] that
the way in which components are combined (as in who uses who) does not
make a difference.  Also, in personal communication, you've mentioned
that you think the SANE exception is ambiguous enough to work in both
directions (even though the LICENSE file tries to clarify the issue).
So, I would think that the epkowa backend is in the clear here.

[1] http://lists.alioth.debian.org/pipermail/sane-devel/2008-June/022199.html

# Not saying I like the current situation with the epkowa backend but
# that's a personal issue.

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