Subject: Re: Qt and the GPL
From: Rick Moen <>
Date: Tue, 5 Sep 2000 20:45:58 -0700

begin David Johnson quotation:
> Okay, followup question. If a BSD application automatically converts
> to the GPL by linking to a GPL library, can the application still be
> distributed under the BSD license?

A licence adheres to a particular _copy_ of a copyrighted work.  Take a
third party's BSD-licenced application and link it against a GPLed
library, and the resulting composite work can be distributed only under
the GNU GPL, as a result of the library's licence (absent separate
permission from the copyright holder).

Meanwhile, the original application copy, sans GPLed library, remains
distributable under its original BSD-type licence.

> Second follow up. Does this mean that another party can change my
> license to the GPL against my wishes by merely linking my code to a
> GPL library?

As to that _copy_, he can indeed create a composite work that legally
cannot be distributed except under the GNU GPL (absent separate
permission).  However, you are contradicting yourself in asserting that
this is "against your wishes".  You would have embodied your wishes in
the terms of the BSD-style licence you chose for public usage of your

Presumably, you would have _read_ that licence before using it:   The operative clause
says "Redistribution and use in source and binary forms, with or without
modification, are permitted...."  Note the _extremely_ broad set of
permissions it grants.

> I thought (and still believe) that only the copyright holder can
> change the license.

As copyright holder, you can grant the public rights to do many things,
including appropriate copies of your work for other purposes under other
licences.  If you don't want to grant such rights, don't use a licence
that confers them.

Cheers,                   "Teach a man to make fire, and he will be warm 
Rick Moen                 for a day.  Set a man on fire, and he will be warm       for the rest of his life."   -- John A. Hrastar