There could be a bug on the code snippets included inside the post, sorry. Check the code running at compiler explorer, it's working and you can see clearly the

There could be a bug on the code snippets included inside the post, sorry. Check the code running at compiler explorer, it's working and you can see clearly the result string literal at the end of the assembly. The point of the example is: We represent a string as a variadic pack of chars, and build_string is a metafunction that builds that kind of string recursively given a starting character and a size. Inside that metafunction we define an aux metafunction build_string_impl that does the job, we only have to pass the required initial parameters (The count of chars and the initial empty string). The first partial specialization acts as the recursive case of that function, and the second is the base case (note count is 0 in that case).