As pointer + length is span in essence, that makes sense. However I'm not sure it's worth us persuing it, although I can see the value for C. 
Making the ntmbs functions not broken has value, particularly since they are, iirc, used in as if specification in places. 

On Mon, Sep 2, 2019, 16:28 Henri Sivonen <> wrote:
On Mon, Sep 2, 2019 at 2:00 AM JeanHeyd Meneide <> wrote:
> On Sun, Sep 1, 2019 at 12:07 PM Steve Downey <> wrote:
> >
> > That was, if I recall correctly, about the C standard library interfaces in the Null-terminated multibyte strings section. Basically that the character at a time interfaces are not amenable to vectorization.
>      With ptr + length, someone can optimize the resulting call as
> much as they like. With null-terminated versions of the function, I am
> skeptical the same performance can be achieved without first calling
> strlen() but I have no experience or data to back up that intuition.

I see.

To me it seems clear that C APIs on this topic should use pointer and length.

Henri Sivonen
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