The trick is in what constitutes "combination", particularly re. static vs. dynamic linking. My understanding is that, at least with LGPL, you can have a close

The trick is in what constitutes "combination", particularly re. static vs. dynamic linking. My understanding is that, at least with LGPL, you can have a closed source program distributed with a LGPL shared object/dll (plus license text) that gets loaded dynamically, but I don't think you can do that with GPL proper. Static linking (IIUC) is right out (for closed source projects).