faster strlen?

Question

Typical strlen() traverse from first character till it finds \\0. This requires you to traverse each and every character. In algorithm sense, its O(N).

Answer 1

Actually, glibc's implementation of strlen is an interesting example of the vectorization approach. It is peculiar in that it doesn't use vector instructions, but finds a way to use only ordinary instructions on 32 or 64 bits words from the buffer.