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Re: psql & readline & win32

From: "Andrew Dunstan" <andrew(at)dunslane(dot)net>
To: <gsstark(at)mit(dot)edu>
Cc: <tgl(at)sss(dot)pgh(dot)pa(dot)us>, <xzilla(at)users(dot)sourceforge(dot)net>, <pgsql-hackers(at)postgresql(dot)org>, <mha(at)sollentuna(dot)net>
Subject: Re: psql & readline & win32
Date: 2006-01-02 22:27:48
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
Greg Stark said:
> Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>> Robert Treat <xzilla(at)users(dot)sourceforge(dot)net> writes:
>> > On Sunday 01 January 2006 18:51, Andrew Dunstan wrote:
>> >> This has been debated ad nauseam in the past. The consensus, bar a
>> >> few people with more advanced paranoia than I suffer from, is that
>> >> we can ;-)
>> > I don't think it is good practice to ship packaged software that is
>> > statically  linked to a gpl library and then claim that your package
>> > is bsd licensed.
>> Robert is 100% right.
> I suspect Andrew was mixing up two different aspects of this.
> There isn't much dispute that shipping a binary linked (statically or
> dynamically) with a library depends on your license to distribute
> derivative works of that library. Ie, that Andrew's wrong and shipping
> a binary linked with a GPL'd library is only legal if you follow the
> terms of the GPL.
> There is controversy over whether the software that requires that
> library becomes a derivative work itself. For example whether a Gimp
> plugin that is useless without the Gimp would be a derivative work of
> the Gimp itself and be undistributable unless you followed the Gimp
> license terms.
> Most people do agree when the question is put for something like Gimp
> plugins but seem to draw a distinction between that and things like
> Postgres that happen to depend on linking with libreadline where
> libreadline is a rather incidental part of the whole system.
> In RMS's view (and the view of the actual practicing lawyers who have
> examined this question when real money was on the line, but then I
> guess lawyers are paid well to have more advanced cases of paranoia
> than Andrew) is that there's no such distinction in law and having
> software that depends on libreadline is just as much bound by the GPL
> as a Gimp plugin.
> But that said, in the case of a binary there's really no controversy. A
> binary that's linked against libreadline clearly can't be legally
> distributed without following the terms of the GPL.

First, note that readline is ONLY used in psql. So there is no question of
GPL for most of our code.

In any case, you don't have to GPL the code, as I understand it.

The readline home page at says:

Readline is free software, distributed under the terms of the GNU General
Public License, version 2. This means that if you want to use Readline in a
program that you release or distribute to anyone, the program must be free
software and have a GPL-compatible license.

Our BSD license is recognised as a GPL-compatible license.

OTOH, if I were a company distributing a closed source postgres
distribution, I would probably not link my psql with readline.

Interestingly, some Gnu software (e.g. bc) has the option of linking with
readline or libedit. It's really a pity that libedit doesn't seem to be as
well maintained.

I really don't see that the Windows binary installer is any different from
the binary installers that most Linux distros have, and they are all linked
with readline.



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Subject: Re: psql & readline & win32
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