Re: [Boost-users] [serialization?] converting utf8 string to unicodewstring

Subject: Re: [Boost-users] [serialization?] converting utf8 string to unicodewstring
From: Eric MALENFANT (Eric.Malenfant_at_[hidden])
Date: 2009-10-08 09:58:50

boost-users-bounces_at_[hidden] wrote:
> Hello,
> 
> I try to accomplish the subj with help of boost's
> utf8_codecvt_facet.

[snip]

>  std::locale utf8_locale(old_locale, new
> boost::archive::detail::utf8_codecvt_facet());
>  std::locale::global(utf8_locale);
>  std::stringstream in;
>  in.imbue(utf8_locale);
>  in.str(utf);
>  std::wstringstream out;
>  out << in;
>  std::wcout << out.str() << std::endl;
> }
> 
> The above code doesn't work: "out" buffer doesn't contain
> correct unicode interpretation of the string.
> Actually, all i want is a c++ equivalent to the following WinAPI:
> 

I *think* that this invokes operator<<(const void*) on "out", passing
the results of operator void*() on "in".

What may have had a chance at producing something near the desired
behavior would be to invoke operator<<(wostream&, const char*), like:
  out << in.str().c_str()

Sadly, this won't work either as this uses ctype::widen, not
codecvt::do_in to make the conversion. AFAIK, the only use of codedcvt
in the iostreams library is for the conversion between the "external"
and "internal" encodings done by basic_filebuf. To get the desired
behavior, I think you'll have to write your own operator<<(wostream&,
const string&) and use the codecvt facet inside it. IIRC, C++0x includes
things like wstring_convert to do that.