Subject: Re: Base Perl modules with BSD software
From: Matthew Flaschen <matthew.flaschen@gatech.edu>
Date: Fri, 13 Jul 2007 01:07:26 -0400

Philippe Verdy wrote:
> Look into the GPL, and you'll see that it does not automatically assigns the
> GPL licence to the data that is fed into or produced by the GPL program,

I have read the GPL, and am well aware of that.

> if this data itself is not licenced by the GPL, and if the output does not
> contain significant parts of data that can be derived directly from the GPL

This is essentially why a Perl program that uses GNU Readline is (in the
FSF's view at least) derived from it.

> Users can then use GPL programs with their own private data, and
> redistribute the result produced without being bound to the GPL licence.

Generally true.

> Otherwise, you could not even legally play a copyrighted music file using a
> GPL-licenced media player...

GPL software is copyrighted.  But of course you can play proprietary
media in a GPL player.  That is not the same thing as linking a
proprietary program to a GPL library.

> [snip examples]

> (and all this is independent of the type of licence that covers the input
> data: the copyright on this data is not automatically reassigned, its

The GPL never reassigns copyright; it couldn't, and doesn't try.
Anyway, I'm aware none of those examples require the output to be GPL.
A GPL Perl module is a significantly different case.

Matt Flaschen