Re: Use of GPL'd code with proprietary programs

[Per Abrahamsen]

Haakon Riiser <hakonrk@ulrik.uio.no> writes:

> AVD communicates with its clients via shared memory, but according
> to the GPL FAQ, shared memory communication is too close for
> the program to fall under the aggregate clause, which the FAQ
> states only applies when the GPL program communicates with the
> non-GPL program via sockets, pipes and command line arguments.

I doubt most court would draw such a technical distinction between
shared memory communication and socket communication.  It is probably
better to think of that as a "rule of thump" of how to avoid getting
in legal trouble with the FSF.

In court I suspect it would matter more how "generic" the interfaces
between the components are.  If the interface is only used to connect
two specific components, I suspect you would be in trouble even if
using command line arguments.  On the other hand, if the interface is
an implementation of a popular iso standard, distributing statically
linked binaries may be legal (as long as you distribute source for the
gpl part).

Anywhere, not getting into court in the first place is more useful
than being able to win, so going with the FSF interpretation is a good
idea.

> However, we also need to use the WMV9 decoder with AVD and this
> WMV9 decoder belongs to Microsoft, so obviously we can't release
> /it/ under the GPL.  

Some MS licenses even have some specific anti-GPL clauses.  

> I didn't see this as a problem, because
> we wrote AVD from scratch, and are allowed to dual license it:

You could also LGPL it, should have the same effect.

> Unfortunately, it gets a little more complicated than this: AVD is
> also used by other programs that need to play sound.  For example,
> let's say we have a proprietary Tetris game that wants to output
> sound effects.

I think that would legal in most jurisdictions, but not accepted by
the FSF interpretation.  You _may_ be able to get around it if you can
somehow get the "special exception" for "libraries normally bundled..."
into effect.

> As a key rule we are advised: "When using the part of
> the GPL that places restrictions on the distribution of programs
> that link against GPL'd code, legal restrictions only apply when
> the GPL'd code is /modified/.  

I never heard that interpretation before.