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Re: [Bug-readline] How to determine the GPL version at compile and run t
From: |
Chet Ramey |
Subject: |
Re: [Bug-readline] How to determine the GPL version at compile and run time ? |
Date: |
Sun, 15 Jun 2014 00:37:33 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 |
On 6/14/14, 4:19 AM, Thomas Schmitt wrote:
> Hi,
>
> GPLv2+ licensed libisoburn includes <readline/readline.h> which on
> my system says
> "GNU General Public License [...] either version 2, or (at your option)
> any later version."
>
> Nevertheless, there is a Debian bug which indicates that meanwhile
> the license of their libreadline is GPLv3+.
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=749801
Readline's license changed from GPLV2+ to GPLV3+ between readline
versions 5 and 6, with version 6.0 released in February 2009. The current
version is 6.3. It's entirely possible that libisoburn includes a
copy of readline 5.2.
>
> libisoburn states its license GPLv2+ in human readable output.
> But i understand this is not true anymore if the GPLv3+ version
> of libreadline is included and/or linked.
> For clarity, i want to adapt that human readable text.
>
> So how do i find out at compile time and especially at run time
> what GPL version is granted by libreadline ?
There is no way to do it other than looking at the value of the
RL_VERSION_NAJOR define in readline.h. If it's at least 6, that
version of readline is licensed under GPLV3+.
>
> Would it be legal to link a program, that was compiled with
> the GPLv3+ header, with a libreadline.so that is under GPLv2+ ?
> Does libreadline prevent such a license mix ?
> Does libisoburn have to prevent it ?
> How much obligation for own effort is legally imposed on users of
> libreadline ?
These are mostly questions for address@hidden, but readline does nothing
to prevent such theoretical version mismatches. It's unlikely, however,
that a program compiled using readline version 5 headers would work
without problems when linked with readline version 6.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU address@hidden http://cnswww.cns.cwru.edu/~chet/