Static link GUI project as dynamic library

Question

My app has 2 projects: logic.dll and GUI.dll. Currently, its size is 1MB, but the whole app's size is 60MB+ due to the dependency dlls.

I've read about QT-LGPL license and know that to keep my app closed-source and commercial posibility without paying license fee, I have to compile it dynamically.

My question is:

1> Can I compile GUI project statically to create dynamic library GUI.dll and public code or object file of GUI.cpp under LGPL?

2> Then compile logic project with GUI.dll dynamically under LGPL and keep logic.cpp closed-source (ofcourse for commercial app)?

Answer 1

If your GUI project is released per the terms of the LGPL, including its entire source, not just the object file, then dynamically link to it with your logic application, you'd be OK.

You either need to straight up dynamically link to the LGPL library, or provide some other LGPL compliant mechanism by which the users of your software can modify the LGPL library and use the modified version in your application.

If you are going to use QT, just dynamically link to it like a normal person.