Bug in C++ locales and streams?

[Roger Leigh]

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Using the example code below, the output is as follows (Debian
GNU/Linux, GCC 3.4.3, glibc 2.3.2):

$ ./test
Umlaute: ??ss

If I uncomment the std::locale::global line, I get this:

$ ./test
Umlaute: ïüß

In both cases, the user's locale is en_GB UTF-8, and the de_DE locale
is also using UTF-8 as its codeset.  The program was compiled as
follows:

g++-3.4 -finput-charset=UTF-8 -o test test.cc


What's worrying me is the need to set up the global locale.  Surely
imbuing the correct locale in the std::wcout stream should be
sufficient?  In fact, commenting out the imbue step (keeping the
std::locale::global line uncommented) doesn't show any difference in
output.

Without std::locale::global set, it looks like the locale is C, and
the stream is iconv()ed to US-ASCII, which turns ß to ss, but can't
represent ï and ü.

Is this a bug?  Is the imbued locale having any effect whatsoever?


Many thanks,
Roger

[test.cc, UTF-8 encoded]
#include <iostream>
#include <locale>
#include <string>
using namespace std;

int main(void)
{
  // Set up locale stuff...
  //std::locale::global(std::locale(""));
  //std::wcout.imbue(std::locale());

  wcout.imbue( locale("de_DE") );

  wcout << L"Umlaute: ïüß\n";

  return 0;
}

- -- 
Roger Leigh
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