Re: xpdf?

[Andrew Smith <amsmith hempseed com>]

Stefan Skoglund <stetson@ebox.tninet.se> writes:

> Hmm, not really. It is entirely ok to use GPLed code
> in something which is LGPL and you can also distribute it but
> you can't use libgtk for developing some software without putting
> that too under GPL ie every application would have to be GPL.

The relevant portions of the licenses are: (first from the GPL)

    b) You must cause any work that you distribute or publish, that in
    whole or in part contains or is derived from the Program or any
    part thereof, to be licensed as a whole at no charge to all third
    parties under the terms of this License.

By "this license" it is referring to the GPL, not the LGPL. Now from
the LGPL:

    3. You may opt to apply the terms of the ordinary GNU General
    Public License instead of this License to a given copy of the
    Library.  To do this, you must alter all the notices that refer to
    this License, so that they refer to the ordinary GNU General
    Public License, version 2, instead of to this License.

In other words, it is legal to convert code from LGPL to GPL, but not
from GPL to LGPL, because the LGPL has a weaker copyleft than the GPL
and if GPL code were placed under the LGPL it could then be used in
situations that the author intended to forbid through use of the GPL.

If xpdf is GPLed, code would still have to be GPLed, so it could not
be placed in GTK+ or libgnomeui without changing their licenses to
full GPL, which would prevent non-free programs from using them.

> But the copyright owner of xpdf could very well release some version
> under LGPL. Which is very important to understand.  GPL and LGPL is
> written such that the copyright owner can't change the distribution
> terms but he can very well decide to release something under an more
> restrictive term and after that stop doing work on the GPL
> version. He/She can't of course use improvements done by other
> people on the GPLed version.

AFAIK the copyright holder is the only person who has legal grounds to
prosecute people for violating the GPL, so he or she can change the
license, assuming he or she isn't intending to prosecute him or
herself.

> Which is probably the major point with GPL and LGPL.
> 
> The BSD licence is written such that it is possible to import BSD
> licensed sw in commercial sw (for ex SunOS) without having
> to disclose your own sw.

-- 
Andrew Smith
amsmith@hempseed.com