Unicode string

[eric]

On Sun, 2011-06-26 at 16:52 +0200, Axel Freyn wrote:
> Hi Eric,
> 
> On Sun, Jun 26, 2011 at 07:15:54AM -0700, eric wrote:
> > Dear c/g++ advanced programers:
> >  I copied and tried to test a piece simple code which is used for
> > (Hardcoding a Unicode String) from the book (
> > C++ Cookbook) by D. Ryan Stephens, Christopher Diggins, Jonathan
> > Turkanis, and Jeff Cogswell
> > at Chapter 13, Internationalization, section 1: Hardcoding a Unicode
> > String
> > example 13-1, it can compile and run on my g++4.5.2, but I don't quite
> > satisfy its result
> > 
> > --------------------
> > //Example 13-1 Hardcoding a Unicode string
> > #include <iostream>
> > #include <fstream>
> > #include <string>
> > 
> > using namespace std;
> > 
> > int main() {
> > 
> >  // Create some strings with Unicode characters
> >  wstring ws1 = L"Infinity: \u221E";
> >  wstring ws2 = L"Euro: \u0128";
> > 
> >  wchar_t w[] = L"Infinity: \u221E";
> > 
> >  wofstream out("tmp\\unicode.txt");
> >  out << ws2 << endl;
> >  wcout << ws2 << endl;
> > }
> As far as I know, you should absolutely NOT use non-ascii characters in
> input/output operations without explicitely specifying the
> encoding/localization to be used.
> In your example, I would thus propose to add after the "wofstream
> out..." a line like
>  out.imbue(locale("de_DE.UTF-8"));
> which defines the encoding. 
> The following works for me:
> 
> #include <iostream>
> #include <fstream>
> #include <string>
> using namespace std;
> int main() {
>  wstring ws2 = L"Euro:\x20ac";
>  wofstream out("unicode.txt");
>  out.imbue(locale("de_DE.UTF-8"));
>  out << ws2<< endl;
> }
> 
> (besides, the Euro-symbol in Unicode is \x20ac)
> 
> 
> In addition, you SHOULD add error-checking to your code. If you add
>   if(not out.good())
>     cerr << "Error while writing " << endl;
> AFTER the line which writes into the file, you'll get an error message ....
> 
> HTH,
> 
> Axel
> 
---------------------------
Dear Axel:
  Thanks your reply.
  I copied your code and tried on my system.  It compile and run, but
reponse by
---------------------------
root@eric-laptop:/home/eric/cppcookbook# ./a.out
terminate called after throwing an instance of 'std::runtime_error'
  what():  locale::facet::_S_create_c_locale name not valid
Aborted
--------
Do you konw what can be improved more?
looking to see your(or any advancer's) suggestion again, thanks a lot 
in advance, Eric