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I've recently run into some argument with a person that claims to be a lawyer (I have my suspicions about this not being completely true, though).

As far as I know, copying even one line of code from GPLed program into proprietary body of code requires you to release the whole thing under GPL, if you ever decide to publish the software and make it available to the public.

The person in question claims that it is "absurd" (I know it is, but AFAIK that's how GPL works), it is "redefining the copyright", "GPL has no power to do that", and claiming that "one line of GPLed code makes you release the whole thing under GPL" is absurd. That contradicts the GPL FAQ.

Can somebody clarify the situation? Am I right in assumption that copying even smallest subroutine from GPL program into your code automatically makes your program a "derived work" which means you are obliged to release it under GPL license if you publish it?


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closed as off-topic by durron597, MichaelT, Snowman, GlenH7, gnat Jul 5 at 1:33

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Only one line? Good luck to establish the evidence. –  mouviciel Nov 14 '11 at 8:32
This isn't actually a software license question. If the new work is a "derived work" from a GPLed original, it needs to be under the GPL. If not, then copyright and hence the GPL don't apply. The question is, specifically, whether the new work is a derived work according to the definitions used in copyright law. IANAL, but I really doubt that copying one line is sufficient, under copyright law, to make a program a "derived work". You should consult a lawyer to see how much you can likely take from a GPLed program without making a derived work. –  David Thornley Nov 14 '11 at 16:22
I just sold some code which contained a line that said i++; Should I be worried? –  Mawg Nov 28 '14 at 15:33
@Mawg: You should be, since it indicates possibility of poor coding style. In most cases iterator name should be descriptive and self-explanatory, such as "nameIndex". "i" is pretty much acceptable only in very short for loops, in which case it doesn't get a line for itself, or when it is used in mathematical sense and actually means "i". Also, the question was asked 3 years ago. Accepted answer covers legal part of your query. –  SigTerm Nov 29 '14 at 11:18
I'm voting to close this question as off-topic because it asks for very specific legal advice that we cannot provide. Please read What types of legal questions are on-topic here? and When is a software licensing question on topic? –  durron597 Jul 1 at 21:33

2 Answers 2

Short version:

Probably. Ask a lawyer to be sure.

Long version:

The key part of this question boils down to "what amount of code is protectable under copyright?" That's what the GPL is founded on - copyright protections. If you can't copyright something, then the GPL can't protect it.

Fortunately, there's a paper that was written by the Software Freedom Law Center titled Originality Requirements under U.S. and E.U. Copyright Law that goes into this with much greater detail that I, as a programmer, can properly interpret. You will likely need to ask a lawyer.

That said, and I'm going to preface this with "I'm only remotely familiar with US copyright law", I am going to go into the "is a single line of code copyrightable" which in turn will answer the "does one line of GPL'ed code make the entire work a derivative work?" If you have any doubts about my answer (and you should) and that this is something important (you've got some code), you should instead talk to a lawyer. Note that different thresholds exist in different countries which may mean that something that a contributor wrote in a different country may be copyrighted even though if you wrote the same thing in your country it wouldn't.

That said, it appears that the Software Copyright Directive from the European Community in 1991 unified the copyright standards across European Community. This had the effect of bringing the laws closer to that of the United States interpretations for originality.

A computer program shall be protected if it is original in the sense that it is the author's own intellectual creation. No other criteria shall be applied to determine its eligibility for protection.

One of the key parts of copyright law is the threshold of originality (though note that some places work on the sweat of the brow doctrine - the US law specifically rejects this). The creativity element is a very low bar and easily passed (you can read more about that at Feist Publications, Inc., v. Rural Telephone Service Co.)

While it is a very low bar, it is not non-existent:

An author’s expression does not need to “be presented in an innovative or surprising way,” but it “cannot be so mechanical or routine as to require no creativity whatsoever.” A work that it is “entirely typical,” “garden-variety,” or “devoid of even the slightest traces of creativity” does not satisfy the originality requirement. Feist, 499 U.S. at 362. “[T]here is nothing remotely creative” about a work that merely reflects “an age-old practice, firmly rooted in tradition and so commonplace that it has come to be expected as a matter of course.” Id. at 363. Likewise, a work “does not possess the minimal creative spark required by the Copyright Act” if the author’s expression is “obvious” or “practically inevitable.” Id. at 363.

Although the creativity standard is low, it is not limitless. Id. at 362. “There remains a narrow category of works in which the creative spark is utterly lacking or so trivial as to be virtually nonexistent. Such works are incapable of sustaining valid copyright.” Id. at 359 (citations omitted)

Further reading about this at Compendium: Chapter 300 Copyrightable Authorship: What Can Be Registered. The originality requirement is section 308.

And so, from this, I would conclude that while i = 0; is not copyrightable, and thus something that will not cause the work to be a derived work, anything more complex could be and thus firmly in the realm of lawyers to battle it out. One line of code from a GPL'ed source may very well be enough to cause the entire work to fall under the GPL as a derived work. If this is an issue, ask a lawyer.


Copyright law is quite specific in allowing "quotes" or small extracts from works to be included in other works.

How small is a matter of much case law but four of five lines could easily be quoted without any danger of violating copyright.


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