Re: std::locale ctor fails (L10n with C++)

James Kanze <>
Sun, 30 Mar 2008 03:14:34 -0700 (PDT)
On 29 mar, 19:21, Sashi Asokarajan <> wrote:

recently I stepped over Strotrup's TC++PL (third ed.) Chapter D.1
where the localization support of the C++ stdlib is explained.

Unfortunately the constructor fails if I try to instantiate
std::locale for locales other than C or POSIX.

Are they installed correctly? There's no guarantee that other
locales are available. (For that matter, there's no guarantee
that POSIX locale is available unless you're on a Posix system.)

With (only)
LANG="de.DE.UTF-8" set in ENV the following code thows an
exception: std::locale loc("");

and std::setlocale(LC_ALL, ""); works fine?!

My GCC Version is "gcc (GCC) 3.4.6 [FreeBSD] 20060305" and I'm
using FreeBSD 6.2.

Here's my example code:

#include <clocale>
#include <iostream>

int main()
  using std::cout;
  using std::endl;

  const char* const lstr = std::setlocale(LC_ALL, "");

  if (lstr)
   cout << "lstr=" << lstr << endl;
   cout << "lstr=NULL" << endl;

  std::locale loc("");
  cout << "std::locale loc=" << << endl;


terminate called after throwing an instance of 'std::runtime_error'
   what(): locale::facet::_S_create_c_locale name not valid
Abort (core dumped)

Does anyone have similar problems ? What am I doing wrong ?
Is the libstdc++ incomplete on my platform?

I *think* that the libstdc++ bases itself on the installed
system locales, but I'm not at all sure how. Under SuSE Linux,
with g++ 4.2.1, if I set LANG to "de_DE.UTF-8", it works for me.
(Note that it didn't work with older versions of g++. I don't
know when it started working, however, although I thought it was
before 4.0. Maybe all you need to do is upgrade.)

James Kanze (GABI Software)
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