That's not correct (at least not according to my understanding). GPL license "attaches" itself to any project that uses it. So by including any GPL licensed library, you must also release the source code of the thing you are including it in. The LGPL allows you to use the library in a project and only commit back changes to the library but not open source the project you use it in. So if that's your intent (to just make sure that library-level changes are contributed back, but not to only restrict usage of the library to fully open-source projects), I would suggest going with LPGL (or, again, MIT, if you want people to be the most comfortable including your library in their projects). More info here:

http://stackoverflow.com/questions/94346/can-i-legally-incor...