Re: [PATCH] Support for mbsnrtowcs and wcsnrtomb

[SODA Noriyuki <soda%yuruyuru.net@localhost>]

>>>>> On Fri, 26 Apr 2013 11:07:01 +0200,
      Joerg Sonnenberger <joerg%britannica.bec.de@localhost> said:

> On Fri, Apr 26, 2013 at 10:15:17AM +0200, Antoine LECA wrote:

>> How can this be correct?
>> 
>> if mbrtowc returns -2, it means there is not enough characters
>> (remaining in the buffer) to complete a conversion; however this is not
>> an error condition (yet); and clearly there is no "illegal sequence". In
>> such a case, mbs[n]rtowcs should stop at this point, leaving the rest of
>> the string for a further ("restartable") call; this is achieved by
>> returning *s=s0, i.e. updating the passed-in pointer to point to the
>> still-to-convert string; in other words, just
>> goto bye;
>> does the job here.

> I'm not sure about that reading of the standard. OpenGroup says
> conversion stops early:
> 
> "A sequence of bytes is encountered that does not form a valid
> character."
> 
> If mbrtowc returned -2, the remaining part of the string is clearly not
> a valid character (yet). I'm not saying you are wrong, just that I am
> not sure of the exact meaning here. This applies to mbsrtowcs as well.

What Antoine pointed out is correct.
Partial parsing is one of important features of mbstate_t related
functions.  You shouldn't treat it's EILSEQ.  That's a critical bug.
-- 
soda