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Re: The GPL and you

Quoting Daniel Isacc Walker (dwalker@cats.ucsc.edu):

> It appears that way .. However, something else comes to mind.
> Some PHP applications are closed source. My code would facilitade a close
> source PHP script to _use_ talkfilters . But that's not a violated either,
> even if I keep it closed?

I'm not sure I understand that last sentence.

Let's recap:  You've written some PHP code supporting PHP access to a
GPLed library, talkfilters.  (You haven't specified what licence you
have placed your PHP glue code under.)

You are absolutely free to issue your PHP glue code under -- the code
you're asking about -- under any licence whatsoever.  A person who 
uses that code does not thereby violate any licence.  (Neither the GPL
nor the PHP licence regulates software usage.)  

Third parties who assemble the three codebases (the PHP interpreter,
your code, and talkfilters) apparently thereby create a derivative work
that is in licence conflict.  _Their_ redistribution of the three
codebases together would thus seem to constitute (technically) copyright
violation, to which the talkfilters author could in theory object.

> Ok, so the GPL doesn't apply unless I distribute something.

Let's be more precise, please:  If you accept someone else's work
subject to the terms of GPLv2, then your subsequent redistribution of
that work (or one that is derivative of it) entails obligations -- about
which you can read in the GPL text.

> Then it only applies if I create a derivative work, being source or
> binary?

Once again:  Read the GPL.  

If you simply distribute your own glue code, you incur no obligations
from anyone else's licensing.  (Why would you?)  If you merely put your 
glue code on (e.g.) the same CD-ROM as talkfilters and/or the PHP
interpreter, and redistribute that, the combination imposes no
obligation on you:  As GPLv2 puts it, that is "mere aggregation".  

If you distribute your glue code linked with the PHP interpreter and
talkfilters, that derivative work's distribution (given that it is in
licence conflict) very minimally violates the talkfilters author's
copyright.  He could theoretically object.


Cheers,               Dogs may have kept us company on the hunt, but it was 
Rick Moen             the cats who insisted we invent houses and discover fire.
rick@linuxmafia.com                                    -- Khiem Tran

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