Say I have a commercial C++ library that defines several different classes. The header files and the library/dll make up the product.
Now say I decide to take the header files, and rewrite the “guts” of the library. Basically, I’d recreate the library, keeping the exact same class names and public interface methods/attributes, but writing all of the underlying implementation code myself.
Would it then be illegal or a copyright issue to sell that recreated library as a replacement for the original?
Does it make a difference if I include extra functionality, say extra methods for some of the classes, that makes it slightly different?
Basically, a clone of the original library, meant to work in place of the original without any code changes to the user’s software (that uses the library).