Apache v. GPL

[John Cowan]

"W. Yip" wrote:

> Is it because of the naming restrictions in Apache constituting additional
> restrictions that are prohibited by the GPL?

No, the GPL can survive that.

> Or is it because of:
> 
> ========
> Redistributions of any form whatsoever must retain the following
>  *    acknowledgment:
>  *    "This product includes software developed by the Apache Group
>  *    for use in the Apache HTTP server project (http://www.apache.org/)."
> ========
> 
> The above sounds like the obnoxious advert clause in the dreaded 'old-BSD'.

Yes, and it is in essence the same restriction.

> Then again, how does an advertisement clause such as the above amount to
> incompatibility with GPL?

Clause 6 says:

# You may not impose any further restrictions on the recipients' exercise
# of the rights granted herein.

Consider a program X that derives from Apache/old-BSD licensed code A and GNU
licensed code G.  Using G requires that X be distributed with a license no more
restrictive than the GPL; in other words, it may not impose restrictions that
the GPL does not impose.  Using A imposes the restriction that every copy of X
must contain the ad from A.

These requirements being contradictory, X may not be distributed at all.
 
> My final question is this. When literature mentions 'compatibility', do
> they refer to compatibility of licenses in a situation involving:
> 
> (i) dual licensing (eg. Perl under both Artistic and GPL); or
> (ii) intermixing of code released under different licenses.

(ii).

-- 

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