Subject: Re: Assistance/advice in choosing a license for POV-Ray 4.0
From: Rodrigo Barbosa <rodrigob@suespammers.org>
Date: Mon, 14 Nov 2005 14:20:23 -0200

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Maybe I didn't answer the "legal question" for the same reason you
didn't answer the "technical question", like: that is not my field of
work. I really though I had that covered with the "IANAL" I wrote.

Even tho I can't point you the the exact USA court rulings on these issues
(1- Not a lawyer, 2- Not in USA), I still would like to point you to
study how these issues apply to both MySQL and dietlibc. These issues
are deeply discussed there, considering:

1) You can only use the GPL version of MySQL in your commercial software
   IF you software doesn't link excusively to it

2) The GPL was chosen as the license for dietlibc for the exact reason of
   stoping non-GPL software from using it (linking against it)

That, if I recall, is also the original reasioning behind the LGPL: so
it can used with non-GPL compliant software. Then again, I'm not one
of the original authors of either of those softwares or licenses, so
all I can give you is an outsider view based on several posts on the
respective websites, mailing lists and the usenet.

Maybe this should be the point where one of us could questiong the FSF
lawyers, or maybe the legal team from MySQL AB about those issues, since
they have been dealing with it for some time now.

Best Regards,

On Mon, Nov 14, 2005 at 10:40:00AM -0500, Rod Dixon, J.D., LL.M. wrote:
> Your answer is incomplete.  The critical legal question you did not answer 
> is: a derivative work of what (or which work)? 
> 
> >On Mon, Nov 14, 2005 at 08:57:10AM +1100, Chris Cason wrote:
> >> So the question is - does dynamic linking result in a derivative work ?
> >> It seems to me that the answer must be 'no'. (If it were 'yes' it would
> >> raise interesting questions on the Windows platform, where it is common
> >> to have third-party libraries hooked into the OS in such a way as to
> >> cause your app to unknowingly load them).
> >
> >IANAL etc etc.
> >
> >It really depends.
> >
> >You see, for you to dynamicaly link some code, you need to make
> >references to it on your own code, so the linker can know how to
> >hook to the functions inside the dynamic library.
> >
> >So, as you can see, you are doing more than simply linking to the
> >library. 
> >
> >(C + Linux follows)
> >
> >When I write a program that will use zlib, I need to both link
> >against libz (-lz) and include its header (#include <zlib.h>).
> >So even if the library isn't inside my code, its header is.
> >And since the header is part of the library, it is covered by
> >its license.
> >
> >At least in that case, I'm 100% it will constitute a derivative
> >work. That is why many libraries (libc etc) as licenses under the LGPL.
> >
> >On the other hand, the dietlibc library is licensed under the GPL. So
> >if you are linking against it, your code MUST also be licensed under
> >the GPL (or compatible license etc etc).

- -- 
Rodrigo Barbosa <rodrigob@suespammers.org>
"Quid quid Latine dictum sit, altum viditur"
"Be excellent to each other ..." - Bill & Ted (Wyld Stallyns)

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