Re: License question

[Chris Vine <chris cvine freeserve co uk>]

On Saturday 10 December 2005 09:16, R. Douglas Barbieri wrote:
> On 12/9/05, Daniel Lidström <daniel lidstrom sbg se> wrote:
> > Hello!
> >
> > I'm interested in using the ustring from gtkmm, but since our project is
> > ``closed'', I need to know how I can use gtkmm. The license is LGPL,
> > which as I understand, only allows linking with non-modified gtkmm.
> > Otherwise we would have to disclose our source code too. But if I use
> > ustring for example,
> > I would have to make sure that it is not a template class, since in that
> > case
> > no code would likely be linked. So in order to use any part of gtkmm, I
> > have to know if that piece of code causes linking with the shared
> > library? This would rule out using any template code that doesn't cause
> > linking with the shared library, in closed source software.
>
> IANAL, but as I understand the LGPL, you can link against it without
> having to publically release your derivative code. However, if you
> modify the files in the gtkmm library itself, you have to share those
> files back out. You do not, however, have to share the files that link
> against the library.
>
> So, for example, if you have a file that uses the ustring class, that
> file you can keep under your own license without release. If you
> create a template that wraps the ustring class, or derives from it,
> that template class is still under your own license. However, if you
> modify the ustring class itself (for example, you add a new method or
> data member, or modify code in an existing method), you are required
> to share only those changes you made to the ustring class itself.

You have missed the point of the question he was asking.  The point is that if 
glibmm (not his code) contains templates released under an unmodified LGPL, 
he would as he says be required to release any source code which instantiates 
any of the templates or links (other than dynamically) with code which 
contains such instantiations.  This would apply to anything using libsigc++ 
(which means that although GTK+ can be used in closed source code, gtkmm 
cannot), but I do not think that Glib::ustring does use templates. However, 
Daniel, why not look at the souce code in glibmm?

Chris