[alsa-devel] Replace include/list.h with non-GPL implementation

[Clemens Lang]

On Thu, Jul 23, 2015 at 09:03:31PM +0200, Takashi Iwai wrote:
> Well, the linked-list macro is a trivial thing each beginner
> programmer starts writing at school.  And, the API itself can't be an
> issue.

I agree, but that does not necessarily mean that the license wouldn't
apply. Consider this thought experiment. You write a two-page prose
article on how a linked list works. Obviously, the concept of a linked
list is trivial -- but does that mean copyright doesn't apply to your
article? I think we have a similar situation here; the concept of a list
may be trivial, but that doesn't mean the implementation is.

> That is, it'd be enough just rewriting the existing list.h (e.g.
> renaming variables, shuffles the call order, rephrase the comments) by
> ourselves without introducing a big piece of codes of even a different
> license, IMO.

Unless you re-implement a list from scratch that provides the same API
that wouldn't really help you. I'm fully aware that it may not be
obvious whether somebody only modified an existing file heavily or
re-implemented it, but unless you start from scratch you won't free
yourself from the original copyright (and thus, the license). That's
also one of the reasons why I'm proposing to use a modified version of
an existing implementation rather than re-writing it from scratch.

A re-implementation would also have to be tested, which the existing
list already is. Additionally, I think the proposed change simplifies
iterating over a list. Currently, you always need list_for_each()
followed by list_entry(), which would be simplified to a single
statement with this change.

-- 
Clemens Lang • Development Specialist
BMW Car IT GmbH • Lise-Meitner-Str. 14 • 89081 Ulm • http://bmw-carit.com
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