Mail Archives: cygwin/2011/02/03/04:42:14
On Feb 3 01:12, Bruno Haible wrote:
> Hi Eric,
>
> > I was asking:
> >
> > should wwchar_t (or xwchar_t, but not xchar_t) be 2-bytes on cygwin, but
> > unlike the POSIX definition of wchar_t being always 1 character per
> > unit, the new type is explicitly documented as being multi-unit on some
> > platforms but with sane semantics
> >
> > or should it always be 4-bytes, where conversion from wchar_t to
> > wwchar_t requires some efforts, and where the new type must be used
> > everywhere (which means wrapping a lot of APIs), but where you can once
> > again assume POSIX semantics of 1 character per unit, simplifying life
> > of callers at the expense of converting to the new type
>
> In the first case we wouldn't need a new type.
>
> The plan is the second alternative. The goal is *not* to have to extend
> each of quotearg.c, regcomp.c, mbchar.h, wc.c, etc. to handle UTF-16
> explicitly with #ifdefs, more variables, and more logic.
>
> > if it works out, should we also add wwchar_t natively into cygwin?
>
> More and more Unix platforms offer only UTF-8 locales. One can predict
> that in 10 years, all Unix platforms will offer only UTF-8 locales. At this
> point wchar_t will be UCS-4 on all these platforms (except AIX).
>
> The mbrtoc32 function from the C1X API that you pointed to will then be
> equivalent to mbrtowwc.
>
> So, you can view 'wwchar_t' as a temporary measure that will bridge the
> gap between the ANSI C Amd. 1 API and the C1X API.
Maybe I'm just dense, but isn't wwchar_t equivalent to wint_t on all
platforms? On UCS-4 platforms sizeof(wint_t) == sizeof(wchar_t) == 4
because there's no reason to make it bigger. On UCS-2 and UTF-16
platforms sizeof(wint_t) == 4 because it must be able to hold EOF as
well. So, why not just use the wint_t type for the time being?
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat
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