On Mon, 2004-10-25 at 18:00, Ville-Pertti Keinonen wrote:

> I really don't know what the legal interpretation of that would be.

I do: creating a compatible component without actually
deriving from GPL sources doesn't breach copyright. In particular,
complying to an interface just by itself cannot breach copyright.

So, for example, a program which was able to accept
readline -- and is able to do so *without* reading any
GPL headers and *without* reading a header derived from
it -- doesn't have to be GPL.

This has nothing to do with what Stallman wants, it's
a universal property of Copyright.

So the code *before* linkage against readline doesn't
need to be GPL. Once linked against readline the result
probably does have to be GPL.

There is actually an example of this: Python. 
The top level interpreter does use readline.
Yet Python sources definitely aren't GPL.

The actual binary, when linked against readline,
probably is. So if you install Python with an RPM,
its a GPL version you have installed. If you use
the tarball the source isn't GPL, but as with the RPM
the binary is.

I don't see that linking statically or dynamically
makes a difference .. except for the amusing situation
that if you actually used dlopen and a shared library,
the licence would change dynamically as you loaded
and unloaded the library . :)))

Oh .. Python doesn't display the GPL licence interactively .. 
even with readline linked in .. (which is probably a breach
of the GPL of readline)

If you have Python installed, type 'license()' in the top
level .. it's quite interesting.

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