Can GPL and Commercial licence coexist in the same software? [closed]

Question

Closed. This question is off-topic. It is not currently accepting answers.

---

Want to improve this question? Update the question so it's on-topic for Stack Overflow.

Closed 8 years ago.

Improve this question

I've been researching for quite a while about the whole issue of selling software originally distributed under GPL, and a question came to my mind. If I create a software X, which uses GPL library ABC, can I distribute my own code under a commercial licence, while maintaining GPL for ABC's code?

I think it should be ok, I don't believe that GPL licence can be enforced on software that uses GPL-ed code.

Answer 1

Let's clarify the first point which is selling the software: The GPL license doesn't prevent you to sell software using it, but it does prevent you from selling it as closed source software. If you're the original copyright owner of the GPL, you may choose to distribute the code under several licenses, and sell it with a commercial license as well. If you don't own all the IP in the code, then you have to comply to whichever license the code you don't own is distributed under. If it is the GPL, you have no choice but to carry that license over to the code you will distribute, as it will be considered a derivative work. With the GPL, you can sell it if you want, but you have to give away the source in the transaction.

Note that with certain languages, software are distributed de facto in source form (scripting languages), and thus the GPL is "automatically" enforced if used.

As for the second point: if both your software and the GPL software can be compiled as standalones programs, and then interact with each other at runtime through some intermediate layer (think 2 processes communicating with TCP or exchanging data via a file), then I guess it's OK, but someone else might have a more informed opinion on this. The LGPL has been devised for a specific case of that situation, namely libraries (DLL or static ones), that's why I am a bit unsure.

If your software includes ABC, or the reverse, then the whole work is a derivative work, and must be GPL'ed.