Does a GPL API infect its apps?

[Ken Arromdee]

On Fri, 22 Oct 1999, Ross N. Williams wrote:
> Thus, my understanding is that if A+B is GPLed, then you could still
> extract B and use it in a way that violates the GPL, so long as you
> can provide a complete genealogy for B under another licence or get
> all of the contributors to B to re-issue under another licence.

If it is possible to provide a complete genealogy for B under another license,
then you haven't extracted B.  You've obtained a separate copy of B.  The
copy of B that is in A+B cannot have a genealogy under another license unless
the _entire_ combination A+B has a genealogy under another license.

> Furthermore, my understanding is that if a program were released
> under GPL and modified by 1000 authors, then even ten years later,
> the entire mess could be taken commercial so long as all of the
> 1000 authors agreed to licence their contributions to the commercial
> venture.

If the authors are contacted and they all agree to use a new license, they
certainly can, of course.  But this does require contacting the author--the
author can't just say "you can license this under GPL or some other license"
and expect people to be able to cut it out of the GPL program and use it under
the other license.  He has to include an extra copy or he has to be contacted
at the moment of cutting.