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Re: Grokking Re: "rescuing" code from the GPL



This is not legal advice.  If you need good legal advice, hire a lawyer.

Shriramana Sharma wrote:
Shriramana Sharma wrote:
2. Y modifies this program to use Qt (under the GPL), creating 02-qt-nothirdvar.cpp, and distributes it under both the BSDL and GPL.

1)

Please explain how this is legal.

Qt is copyrighted by Trolltech. A license provides me rights that normally only the copyright owners have. Any permission the license does not provide me I do not have. I have permission to create a derivative work ("my work") only so long as I distribute it under the GPL.

Trolltech has not given me permission to distribute my work under the BSDL. The fact that I have also distributed my work under the GPL is immaterial. I cannot do something I don't have permission for. So how can I license my work under the BSDL at all?

The problem is that the original "it" above is ambiguous. Is "it" the compiled binary, or the source code?

Source code generally stands on its own. Unless you have cut and pasted sections of Qt code into your source files, or can otherwise be identified as theirs, your source code is entirely yours, and can be licensed by you as you see fit. TrollTech has no say in how your source code may or may not be licensed.

TrollTech has a claim against you only when you compile your source code into a binary, which by necessity pulls TrollTech's creative work into the result. When distributing that binary, people must respect both your license and TrollTech's. That turns out to be easy, since the BSDL's restrictions are a subset of the GPL's. But the fact that it is easy to combine these works does not negate their initial separation or your rights to the parts that are yours.

So should I say:

"This work as a whole is licensed under the GPL. This work or any part of it which is or can be modified to be Qt-independent may be distributed in such a Qt-independent form under the BSDL also".

Is such verbosity really necessary, or is it understood? If it would be illegal to say:

"This work as a whole is licensed under both the GPL and the BSDL"

then I may have no choice but to resort to such verbosity.

For the source code, you can simply apply a normal BSDL copyright notice to each file.

I prefer to put a separate file in my source, explaining the license situation. If you do that, you can explain there how your code is dependent on other things, and that your license does not grant implicit rights to these other things. If you don't provide a separate license explanation, then you should have a license statement in every source file you distribute, as mentioned above.

The license notice for the binary should contain references to both your license and the GPL, as well as licenses for other libraries you may use.

Further, in its Qt-dependent state, if I distribute a compiled form of
my work, then would it still be dual-licensed in that form? Or would it be *only* under the GPL? If yes, then does dual-licensing apply only to source forms?

Since it's difficult to isolate your specific code from the binary, the license for the binary is effectively the GPL. But you should not feel compelled to drop your license statement from the binary just for that reason.



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