I think that your interpretation is correct.syzygy wrote:For something to be a derivative work of an original, it has to contain copyrightable material from the original. In case of a movie and a book, that could be the storyline. In case of computer programs, there is basically only code that could be shared. (The functionality is not copyrightable, for example, but here we are not even speaking about copying of functionality.)Fulvio wrote:It doesn't matter the technical way how you realize the derivative work or if you take only a part of the original. That's why, for example, HBO had to pay George R.R. Martin even if a film is a very different thing from a book, and other authors do not have the rights to write sequels to his books.
In the same way a derivative work of GPL copyrighted material, no matter how created, which restricts in any way the "same freedoms that you received" is an unauthorized use and:
The FSF wants you to believe that using another program's API already creates a derivative work. That is just false.
Linus Torvalds also has interesting ideas about what makes a work derivative. His ideas have no basis in copyright law.
However, we should ponder the spirit of the license agreement (what the intent is). In the case of GPL the idea is that all software using GPL software must also be GPL. Yes, this is very restrictive. But that is the concept that they want.
While I think GPL can be legally circumvented, we should simply choose another licence type if our project needs it.
I love some GPL tools like gcc. But all license types have their dark sides. Personally, instead of trying to legally pass their wishes, I will simply do something with another tool set that does not have the stark requirements.
Now, that having been said, I have used gcc and g++ to write proprietary software. Linus Torvalds would cringe and moan. But I guess we all draw a line *somewhere*