[Python-Dev] (libffi) Re: Copyright issue

[Bill Northcott]

On 28/01/2006, at 8:04 PM, Martin v. Löwis wrote:
>> The compiler needs specific exemptions because parts of the GPLed
>> runtime libraries are included in all compiled code.  No part of the
>> autotools ends up in the finished code.  If it did, you would need m4
>> to run Python and you don't.
>
> It doesn't matter whether it ends up in the finished code: if the
> aclocal.m4 is indeed GPL-licensed, then the entire Python source
> distribution must be GPL-licensed, because it "contains or
> is derived from the Program or any part thereof".

The build tools: m4 scripts, the configure shell script and the  
Makefiles all contain GPL code and are under GPL.

However, none of this ends up in the 'finished program' which is the  
executable versions of Python and its associated libraries.  The  
build tools are just tools not part of the program.  The program is  
not 'derived' from the build tools.

Maybe it would help to put it in a another domain:
Say I decide to write the great Australian novel.  I sit at my  
computer and type in the words.  Those words are my copyright and I  
am able to restrict their use as provided in copyright legislation.   
These rights are inherent and exist regardless of whether or not I  
add a copyright notice.  The notice is just a courtesy and a  
convenience which tells anyone who would like to use the work they  
need to get my permission.  A license is just a set of standard  
permissions passed on with the work.

Now I print out my novel.  That printed version is 'derived' from the  
representation in the computer.  So it is covered by the same  
copyright.  If I compress the computer files, those are still derived  
work.  If some American decides to write the great American novel by  
boiler-plating large chunks of my work with a little of his, then  
that work is derived and copyright to both of us.  His actions are  
legal unless he tries to publish it, which would require my  
permission.  This is analogous to linking a program with a library  
provided by another party.  That is why one needs the specific  
concessions in the gcc compiler to cover the linked run time libraries.

Of course the computer on which I wrote the book has an operating  
system which is copyright.  The word processing software I used to do  
the writing is also copyright.  However none of either program ends  
up in my novel.  So the novel is not derived from them, and their  
copyright holders have no rights over the novel.

I can happily package appropriately licensed copies of the word  
processing software with the finished book.  So that others can try  
their hand at the same thing.  In no way does such an operation give  
the software copyright holders any rights over the book.

This is exactly analogous to including the GPL tools with your source  
distribution.  You must comply with the GPL in respect of the GPL  
code.  So you must include copyright notices and and make any  
modifications or improvements freely available.  However, if you  
build a binary from the sources which does not include or link GPL  
code then the FSF have no rights over it and you are not obliged to  
acknowledge them or include their copyright notice.

A Python binary is no more derived from the autotools than the book  
is derived from the word processing software.

Bill Northcott