[bug-inetutils] Re: Internationalized domain names teaser

["Martin v. Löwis"]

Simon Josefsson wrote:
> ,----
> | Because these resolver libraries today expect only domain names in
> | ASCII, applications MUST prepare labels that are passed to the resolver
> | library using the ToASCII operation. Labels received from the resolver
> | library contain only ASCII characters; internationalized labels that
> | cannot be represented directly in ASCII use the ACE form. ACE labels
> | always include the ACE prefix.
> `----
> 
> I think the IDNA specification gives poor recommendations in this
> area, an area which doesn't even concern the IDNA protocol itself.

But this recommendation is irrelevant for gethostname (and likewise 
getaddrinfo). For ToASCII, the assumption is that the input is a 
sequence of Unicode characters. gethostname does not expect Unicode 
characters, but char*.

Taking the recommendation of IDNA literally, the C library should 
provide the ToASCII function, and it would be the application's task to 
use it. For C, of course, this means that the application needs a 
wchar_t* representation of the label. While this probably should be done 
as well, many applications will appreciate if there is some simpler API 
to access IDNA.

Regards,
Martin