Hi
The following excerpt from Richard Stallman's talk at the 5th
international GPLv3 conference (http://www.fsfeurope.org/projects/
gplv3/tokyo-rms-transcript) indicates that there is a problem with
the CCP4 license.
It is important to clarify this, and, as RMS says, that if you want
to make a more restrictive license, to do this in an unambiguous way.
It has major implications for those wanting to distribute their code
under the GPL (e.g. clipper, coot), but who also rely on code from
the CCP4, typically the library.
-- Morten
"While we were doing this [discussing GPLv3] we decided to try to put
an end to a misuse of the GPL. You may occasionally see a program
which says "This program is released under the GNU GPL but you're not
allowed to use it commercially", or some other attempt to add another
requirement. That's actually self-contradictory and its meaning is
ambiguous, so nobody can be sure what will happen if a judge looks at
that. After all, GPL version 2 says you can release a modified
version under GPL version 2. So if you take this program with its
inconsistent licence and you release a modified version, what licence
are you supposed to use? You could argue for two different
possibilities."
"We can't stop people making their software under licences that are
more restrictive than the GPL, we can't stop them from releasing non-
Free Software, but we can try to prevent them from doing so in a
misleading and self-contradictory way, after all, when the program
says GPL version 2 but you can't use it commercially, that's not
really released under GPL version 2, and it's not Free Software, and
if you tried to combine that with code that really is released under
GPL version 2, you would be violating GPL2. Because this inconsistent
licence starts out by saying "GPL version 2", people are very likely
to be mislead. They may think it's available under GPL version 2,
they may think they're allowed to combine these modules. We want to
get rid of this confusing practice. And therefore we've stated that
if you see a problem that states GPL version 3 as its licence, but
has additional requirements not explicitly permitted in section 7
then you're entitled to remove them. We hope that this will convince
the people that want to use more restrictive licences that they
should do it in an unambiguous way. That is, they should take the
text, edit it, and make their own licence, which might be free or
might not, depending on the details, but at least it won't be the GNU
GPL, so people won't get confused."
- [ccp4bb] The CCP4 license is ambiguous Kjeldgaard Morten
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