Re: non-free application linked to Qt.
"Charles Plessy" <email@example.com> wrote in message
A non-free program for which I maintain a package has changed its UI
toolkit from lesstif to Qt. The program is free for non-commercial use,
and upstream payed for a Qt licence. I understand that producing
binaries within Debian would be an infringement of the Qt licence.
It would certainly seem so. The following message from the trolltech
site seems to confirm that:
#*) Please note if you choose an open source license for your Qt-based
application this license
#needs to be compatible with the Qt Open Source Edition licensing (GNU GPL
#of the licenses listed in Trolltech’s GPL Exception) for your end users to
be able to
#compile, run and further modify your application.
#You may not change the license terms of any parts of Qt itself.
Upstream has asked me if it would be possible to distribute the program
as a source package only, à la 'pine'. Can you confirm that it is the
case? Also, we are wondering if it is the first time this kind of
I'm not sure about the second part of the question, but my understanding is
should be no problem with that solution.
Surely the program in question's licence would not prevent it (or they would
not be asking you).
Then the GPL v2 definately does not prevent linking applications to a
library if the
resulting linked application is never distributed. But yet us assume that
form some reason
the GPL does not allow this.
It would appear theat the second exception to the GPL that trolltech uses
would allow this.
The exception is:
#The right to link non-Open Source applications with pre-installed versions
#the Licensed Software: You may link applications with binary pre-installed
#of the Licensed Software, provided that such applications have been
#and are deployed in accordance in accordance with the terms and conditions
#the Qt Commercial License Agreement.
That would give us therequired permissions to provide it as source for end
users to compile and link,
assuming that that method of deployment is allowed under the "Qt Commercial
That exception notice was found at
Browsing a sample QT commercial licence appears to indicate that the
Qt Commercial License Agreement would allow such distribution if
the licence certificate allows distribution on the OS platforms in question.
(Presumeably it must list Linux systems.)
Upstream sells licences of its program for commercial use, so it is
difficult for them to free their code. The program exists in a graphical
version and a command line version. Both can operate independantly and
the command-line version is widely used on workstations. Would I be
legally wrong if I advised Upstream to separate the GUI code from the
algorithms, double-license the GUI under non-commercial or GPL terms,
and make it call the command-line version independantly (no C linking)?
That could be a reasonable possibility assuming it is reasonably possible
to set it up that way. I've seen many commercial apps whose main executable
just a very large and nice GUI convince wrapper around the command line
tools that do the real work.
If it is reasonably possible for upstream to do that, that would eliminate
this issue entirely.
After all, if it is just a wrapper (even a really nice wrapper) around the
CLI utility, and is not using
undocumented features of the CLI utility then there is no reason somebody
else could have
developed the software independently, and we know that GPL'ed wrappers
CLI tools are entirely legal.
In that case, I think that it would preserve their revenue model: people
who want to use the GUI for commercial use would have to buy a licence
for the commercial use of the command-line version anyway. But I do not
know if it would be fair to Trolltech. Or maybe the licence of the
command-line version could mandate that if the program is used through
the Qt GUI, a Qt license has to be bought?
You are right that this could be deemed unfair to trolltech, especially if
upstream just put the GUI under just GPL,
as that would eliminate the need for them to use the commercial licence.
The goal of this is to keep a gratis and open source access to the
program and its GUI to academic users, and require a commercial licence
from industrial users.
In the split system it would be the terms of the CLI that would be the
deciding factor here.
After all, an industry could legally use the GUI shell without paying, but
without the CLI portion
the shell would be quite useless.
[Please CC me, I am not subscribed]
My overall thoughts are that just the pine-like distribution should be
sufficient, and that the rest may be highly academic anyway,
as it might not be reasonably feasible to restructure the GUI version in the