On Mon, 20 Oct 2014 10:07:20 -0600
Eric Blake <eblake@redhat.com> wrote:

> POSIX requires that NUL, slash, dot, newline, and carriage return all be
> single bytes that cannot occur inside a multibyte character (because
> they have special meaning to file name resolution and/or terminal
> interaction); it added this requirement fairly recently, but only after
> confirming that common existing locales satisfy this constraint.  (The
> same is not true for most any other character; even though POSIX
> requires that a-z, A-Z, and 0-9 be single bytes, it does not forbid
> those characters from also being bytes embedded within multibyte
> characters).  Is it worth extending your optimization to all five of the
> POSIX-guaranteed single byte characters?

I rewrote the patch so that NUL, slash, dot and carriage return as well
as newline might be also regarded as a special character.