I wrote a library that is indeed a subclass of QTreeView. So easily I can attach it to any Qt application that uses QTreeView.
I want to patch a GPL application (GPL_APP) in a way that it searches for my library and if it exists then load it, but if it is not found, GPL_APP will continue to work without it.
I will publish them separately, GPL_APP will released with its full source-code, but library will be closed source.
The library in theory is usable with other applications, but as there is no another application with needed interface to load my library so GPL_APP is the only application that can use my library, and therefore I know in first place that users will combine them.
Is this violating GPL?
Sorry for my bad English.