Subj : Re: Copyright and addons or comercial GUI for a GPL software
To   : comp.programming
From : Giannis Papadopoulos
Date : Thu Aug 11 2005 04:26 pm

aslanski2002@yahoo.com wrote:
> Giannis Papadopoulos yazdi:
> 
>>aslanski2002@yahoo.com wrote:
>>
>>>Jonathan Bartlett yazdi:
>>>
>>>
>>>>>Are there any restrictions in using GPL code in comercial applicatins?
>>>>
>>>>Yes.
>>>>
>>>>
>>>>
>>>>>I have seen the Linux Kernel used on a lot of appliances.
>>>>
>>>>That's because the kernel is not linked to the program.
>>>>
>>>>
>>>>
>>>>>My intention as I mentioned in an earlier  thread is to design a good
>>>>>interface for some GPL applications and to sell this interface.
>>>>
>>>>Selling is not against the GPL.  Selling under non-GPL licenses is.
>>>>
>>>>
>>>>
>>>>>I will
>>>>>not charge for the application itself but I think it is fair to charge
>>>>>for the interface. The design requires a lot of work for design and
>>>>>implementation.
>>>>
>>>>The amount of work is irrelevant.  What is relevant is whether or not
>>>>your work is considered a derivative work.
>>>>
>>>>If you link to libraries, that is usually considered a derivative work.
>>>> Static linking definitely is, dynamic linking using headers supplied
>>>>under the GPL also is.  I do not know of the rules for dynamic linking
>>>>without the GPL headers.  However, if you are not linking to the GPL
>>>>work, but merely using it as a separate application, there is no
>>>>problem.  In fact, I know Mathematica does this.  If you look on the CD
>>>>they distribute you will see a source file containing a GPL application
>>>>which they use as a separate, unlinked application but is distributed
>>>>with Mathematica.
>>>>
>>>>As for LGPL libraries, there are other rules.  With those, you are
>>>>allowed to freely dynamically link.  For static linking, there are more
>>>>rules, but basically you have to provide the unlinked versions of both
>>>>your code and the libraries, so the user can upgrade the library and
>>>>relink if he wishes.
>>>>
>>>
>>>I have questions here:
>>>I have an application *A* which uses a DLL *D1* with (L)GPL code in it
>>>and another *D2* which has no (L)GPL code. *A* still can work if you
>>>delete *D1* (though not fully functional). And *A* has no (L)GPL code
>>>in it.
>>>- Do I still have to provide sources for *A* ?
>>>- I don't think I have to provide the sources of *D2*, do I?
>>>
>>>
>>>
>>>>Jon
>>>>----
>>>>Learn to program using Linux assembly language
>>>>http://www.cafeshops.com/bartlettpublish.8640017
>>>
>>>
>>If D1 is GPL, then yes you have to provide A sourcecode. If it is LGPL
>>you don't have.
>>
> 
> What if I provide *A* and *D1* as proprietary and some knowledge of how
> to create a plug-in for *A*. And some user creates a plug-in for *A* (
> call it *D2*) using some GPL code, isn't this the case where I have to
> provide source of *A*? I can't stop a user doing it!

Hmm, this I don't know.. But if you load the plugin and the plugin is in 
GPL, I believe it is not completely legal - but I could also be wrong...

-- 
one's freedom stops where other's begin

Giannis Papadopoulos
http://dop.users.uth.gr/
University of Thessaly
Computer & Communications Engineering dept.

.