Hi,

On 2026-02-04T22:41:29+0000, Ell via Std-Proposals wrote:
> On Wednesday, February 4th, 2026 at 10:23 PM, Jason McKesson via Std-Proposals <std-proposals_at_[hidden]> wrote:
>
> >
> >
> > OK, so there's this API that has a NUL-terminated string inside some
> > object or system. And you call a function which retrieves a
> > `cstring_view` of that internal string. So...
> >
> > How would that internal string get embedded NUL characters?
> >
> > I mean, if the API expects to work with NUL-terminated strings, then
> > it probably is going to break if you give it a string with embedded
> > NULs. Or at the very least, it will internally truncate the string
> > to the first NUL character, since it is internally storing a string
> > that is required to be NUL-terminated.
> >
> > Put simply, if you're dealing with a NUL-terminated string-based
> > interface, then the string view you get back should respect that
> > behavior. This API shouldn't have a problem with returning a
> > `cstring_view` that truncates the string's length to the first NUL
> > character, since that is precisely what it did internally when storing
> > that string.
> >
> > So I don't see how having the size be correct for `strlen` instead of
> > respecting the size it is given is a problem here.
>
>
> The problem isn't not respecting the size, it's deciding what the
> implications of saying that cstring_view can't have embedded nulls are
> in practice.

Reminder: ISO C defines what is a string, and it disallows embedded
nulls.

Footnote 75 of ISO C23 says:

 75)A string literal may not be a string (see 7.1.1), because
 a null character can be embedded in it by a \0 escape sequence.

It refers to 7.1.1 ("Definitions of terms"), which says in p1:

 A string is a contiguous sequence of characters terminated by
 and including the first null character.


Have a lovely night!
Alex

> I don't think that doing a strlen everywhere is the answer
> (or rather, I think that'll make cstring_view pretty useless).
>
> You deal with it the same way you deal with std::string allowing
> embedded nulls. You validate untrusted input, and then you probably
> assume there are none. And if your string does have unexpected embedded
> nulls then you already have a problem, truncating is just papering over
> it.
>
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