I believe that the legal key is distribution of the licensed code, not linking to it.
The LGPL defines a "Combined Work" and has requirements on what is required when you distribute a combined work together. The intent is clearly that if you distribute the combined work together and DO NOT meet those conditions, then you had no permission to distribute the LGPLed code. And this has force because while the proprietary half of a combined work is not a derived work, you still need permission to distribute some else's copyrighted code and that permission was contingent on what you did with your application. The GPL defines a covered work to be, "either the unmodified Program or a work based on the Program." Later in the license a distinction is drawn between that and "mere aggregation". The intent is that distributing your program + the covered GPLed code it depends on creates a work and you need GPL permission to have distributed the covered GPLed code. (Whether a judge will agree with this interpretation is another question, but I'm pretty sure that the license drafters intended a judge to understand it this way.) With that said, the LGPL gives a lot of license flexibility for your part of the combined work but says you must allow reverse engineering. Which by default is allowed in many places, but is something that many proprietary licenses take away. By contrast the GPL offers no real alternative but to license the code you own under the GPL. Therefore LGPLed code keeps itself copylefted but does not encourage developers to GPL their own code. While GPLed code pushes people who want to use that code to have to GPL the code that they wrote. On Tue, Apr 7, 2015 at 10:23 AM, Lawrence Rosen <lro...@rosenlaw.com> wrote: > Patrice-Emmanuel Schmitz referred me to this thought-provoking link: > > > > https://joinup.ec.europa.eu/community/eupl/news/meaning-%E2%80%9Ccopyleft%E2%80%9D-eupl > > > > Can anyone here precisely identify the language in the GPL licenses that > makes it "strong" rather than "weak" copyleft? And can anyone here identify > anything in copyright law or cases that allow this distinction in the > meaning of "derivative work"? > > > > /Larry > > > > > _______________________________________________ > License-discuss mailing list > License-discuss@opensource.org > http://projects.opensource.org/cgi-bin/mailman/listinfo/license-discuss > _______________________________________________ License-discuss mailing list License-discuss@opensource.org http://projects.opensource.org/cgi-bin/mailman/listinfo/license-discuss