LGPL clarification

[Ian Lance Taylor]

   Date: Wed, 1 Nov 2000 11:52:01 -0800 (PST)
   From: Ken Arromdee <arromdee at rahul.net>

   On Wed, 1 Nov 2000, Bryan George wrote:
   > > > The LGPL puts restrictions on P when it is linked with L.  But so
   > > > what?  That linking will only happen on the end user system.  ...
   > > > But the LGPL puts no restrictions on the distribution of P, which is
   > > > what the proprietary user cares about.
   > > That is not, however, what RMS believes.  If there is only one shared library
   > > that exists, he considers P to be derivative of it even before it is linked;
   > > and this triggers all licensing conditions on L even if P is not distributed
   > > with L.  Remember readline?
   > Readline is GPL'd, not LGPL'd, though, so I'm not sure how that applies
   > in the present discussion.

   RMS's analysis is not directly about the GPL, but about what "derivative
   work" means.  If he's correct, he's correct independently of the actual
   license; *any* license that restricts derivative works will be triggered,
   whether GPL (readline), LGPL, or otherwise.

LGPL, section 5:

      5. A program that contains no derivative of any portion of the
    Library, but is designed to work with the Library by being compiled or
    linked with it, is called a "work that uses the Library".  Such a
    work, in isolation, is not a derivative work of the Library, and
    therefore falls outside the scope of this License.

I read this as saying that the LGPL specifically defines a program
designed to work with the library as not being a derivative work in
the context of the LGPL.

Ian