[quake3] Re: gpl anticheater

[fs]

On Sun, Sep 04, 2005 at 09:34:32PM -0400, tom fogal wrote:
> > The double whammy is that since Q3 is now GPL, it cannot be distributed
> > with any closed source libraries. So implementing a free-as-in-beer
> > alternative to punkbuster is hampered slightly. Correct me if I'm wrong
> > (IANAL etc.), but there is no problem with a GPLed application linking
> > against a non GPL library? <snip>
> 
> I am fairly (but not 100% sure) that this is illegal as per the GPL, if
> done at link time... thats why the LGPL was developed.

k, found a relevant answer about it on
http://www.fsf.org/licensing/licenses/gpl-faq.html#GPLIncompatibleLibs

the link is pretty good about anything gpl related actually.

====

What legal issues come up if I use GPL-incompatible libraries with GPL
software?
    If the libraries that you link with fall within the following
    exception in the GPL:

        However, as a special exception, the source code distributed need
        not include anything that is normally distributed (in either
        source or binary form) with the major components (compiler,
        kernel, and so on) of the operating system on which the executable
        runs, unless that component itself accompanies the executable.

    then you don't have to do anything special to use them; the
    requirement to distribute source code for the whole program does not
    include those libraries, even if you distribute a linked executable
    containing them. Thus, if the libraries you need come with major parts
    of a proprietary operating system, the GPL says people can link your
    program with them without any conditions.

    If you want your program to link against a library not covered by that
    exception, you need to add your own exception, wholly outside of the
    GPL. This copyright notice and license notice give permission to link
    with the program FOO:

        Copyright (C) yyyy <name of copyright holder>

        This program is free software; you can redistribute it and/or
        modify it under the terms of the GNU General Public License as
        published by the Free Software Foundation; either version 2 of the
        License, or (at your option) any later version.

        This program is distributed in the hope that it will be useful,
        but WITHOUT ANY WARRANTY; without even the implied warranty of
        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
        General Public License for more details.

        You should have received a copy of the GNU General Public License
        along with this program; if not, write to the Free Software
        Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
        02110-1301, USA

        In addition, as a special exception, <name of copyright holder>
        gives permission to link the code of this program with the FOO
        library (or with modified versions of FOO that use the same
        license as FOO), and distribute linked combinations including the
        two. You must obey the GNU General Public License in all respects
        for all of the code used other than FOO. If you modify this file,
        you may extend this exception to your version of the file, but you
        are not obligated to do so. If you do not wish to do so, delete
        this exception statement from your version.

    Only the copyright holders for the program can legally authorize this
    exception. If you wrote the whole program yourself, then assuming your
    employer or school does not claim the copyright, you are the copyright
    holder--so you can authorize the exception. But if you want to use
    parts of other GPL-covered programs by other authors in your code, you
    cannot authorize the exception for them. You have to get the approval
    of the copyright holders of those programs.

    When other people modify the program, they do not have to make the
    same exception for their code--it is their choice whether to do so.

    If the libraries you intend to link with are non-free, please also see
    the section on writing Free Software which uses non-free libraries.