Ask HN: GPL copyleft applies to ports?

1 point·jojopotato··5 comments

I'm hoping someone out there knows the answer, but I ported a library from one language to another (C++ to Java).

I was going to release it under a 3 clause BSD, but the original code was licensed under GPL v3. It probably won't ever make a difference, but does the GPL force me to license the port under GPL as well?

Thanks in advance!

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IANAL answer: if you want to release under a different license, you are urged to do a "clean room" implementation that could not possibly have derived anything from the original. If it's a mere translation from one language to another, your version of the library almost certainly falls under the "derivative work" category and needs to be GPL.

If your library implements a well-known algorithm, try to track down a text description of that algorithm (say, a research paper) and redo the code based on that original source. Looking at GPL code can contaminate your final product.

An IANAL answer is perfect for me, it's a very low key project that I ported. I was just hoping to move it from GPL to a 3 clause BSD license.

Yes. Any work that counts as a "derived work" of GPL'd software must be licensed under the GPL. I would think a direct port is almost certainly a derived work.

Yeah, that's what I was afraid of, I guess I'll release it as GPL then.

Or just ask the source.

Ask if you can have it under the license that you want. GPL3 may have been an arbitrary choice and the creators of the copyright work may be happy to either apply a dual license or allow you to apply BSD license to your derivation.

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