app and shared library
As far I understood lib folder could used to place inside it some external libraries that can references through LIBRARIES variable. In my case I would to create a project that contains 1 executable and 1 library where the executable in fact is a demo and test of that library, so that I can use the makefile either to run the app or simply to build the library for other usages. I changed my Makefile follow way but I would to know if I miss something because its sound to me like an hack respect what this extension would provide, I'm wrong ?

By default, the lib folder is meant for static libraries (.a files), not dynamic ones. The template is meant for a basic startup project, so anyone should be free to modify any files to match their needs.
I am not an expert C++ developer and I haven't really used dynamic libraries before :sweat_smile:.