Re: how much is too much?

[David Kastrup]

Chad Whitacre <chad@zetaweb.com> writes:

> I'm trying to determine what the threshold is in terms of lines of
> code I can copy/paste from GPL software before coming under the GPL
> myself.
>
> Is this issue spelled out anywhere?

You don't "come under the GPL".  The original code is under the GPL,
and to use it, you have to heed its licence.  It may not be
distributed as part of something not under the GPL.

The copyright laws of your land determine what amount of code is
actually necessary before you overstep your default legal rights and
require specific license by the copyright holder (which would then be
the GPL).

As a rule of thumb, the FSF requires for contributions copyright
assignments for changes of more than about 10 or 15 lines, unless
those changes are purely mechanical.  It is not more than a rule of
thumb: of course just removing all newlines does not make copyright go
away.

So that would be a ballpark figure for maintaining sole legal
responsibility if you are careful.

Now if your goal is to be reasonably safe from cease-and-desist orders
and similar: few people are going to sue for 15 lines or have a chance
to prevail, and replacing them usually is not much of an issue.  Your
code does not come under GPL under any interpretation of the law: it
is just that putting it under the GPL is the simplest way to comply
with copyright law.  Another way, of course, is to remove the
offending code and replace it with something you wrote yourself.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum