[Qt-interest] Qt Mysql Plugin and LGPL

[Vincent L. Damewood]

On Thu, Jul 9, 2009 at 4:41 PM, Thiago
Macieira<thiago.macieira at trolltech.com> wrote:
> Benjamin Sonnemann wrote:
>>My concern is following:
>>libmysql.dll is GPL, so shouldnt QSqlMysql .dll be also GPL (if used at
>>all!)  and then entire Qt plus my app?
<snip>
> That's somewhat correct. MySQL and its libraries are GPL.
<snip>
> But MySQL AB's model (before it was bought up) was like Trolltech's: show
> the source or pay up. Both were small, independent, Scandinavian companies
> before being acquired. But, like I said, only a lawyer will clarify this.

Also, like Trolltech/Qt Software, MySQL has an exception allowing
developers to use other open-source licenses in works that use the
MySQL libraries.

http://www.mysql.com/about/legal/licensing/foss-exception/

And among the allowed licenses is the LGPL. This, at least, allows Qt
Software to release QsqlMysql as LGPL. For a program that uses
QsqlMysql, there isn't going to be any problem with any of the other
open-source licenses on the MySQL exception list. If you want to go
proprietary, the folks at the Free Software Foundation says no:

http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
http://www.gnu.org/licenses/gpl-faq.html#GPLWrapper

I hope this helps.

Vincent Damewood