I'm thinking things like a basic text search function where you might want to not only say that it is found but where in the document. Returning 0 gives the false impression it is found in the string.
The only time I feel like it could return 0 is if the string it was looking the index up in itself was empty. Even then, it is still searching for nothing and finding an index.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.