Re: numpunct::thousands_sep() makes reading an int fail in locale of VC8

I have an problem reading an int from a istream with VC8. Look at this
little code
   istringstream txt("2,Rest");
   int i;
   if( txt >> i ) cout << i << endl;
   else cerr << "read error" << endl;
The Code results in a 'read error', if I build it with VC8. Debugging
this, I found, that the problem is the thousands_sep()-method which is
initialized in the constructor of std::numpunct. In default the value
is ','. If I imbue a locale - could be the same locale (!) - the value
differs to '\0'. So this code
   istringstream txt("2,Rest");
   txt.imbue( locale("C") );
   int i;
   if( txt >> i ) cout << i << endl;
   else cerr << "read error" << endl;
works correct.
The locale is the same before and after the call of imbue, but the
system calls an different constructor of std::numpunct. A look in the
implementation shows:
// file xlocnum; line 83
explicit __CLR_OR_THIS_CALL numpunct(size_t _Refs = 0)
: locale::facet(_Refs)
{ // construct from current locale
_BEGIN_LOCINFO(_Lobj)
_Init(_Lobj);
if (_Kseparator == 0)
_Kseparator = // NB: differs from "C" locale
_MAKLOCCHR(_Elem, ',', _Lobj._Getcvt());
_END_LOCINFO()
}

__CLR_OR_THIS_CALL numpunct(const _Locinfo& _Lobj, size_t _Refs = 0)
: locale::facet(_Refs)
{ // construct from specified locale
_Init(_Lobj);
}
The first constructor sets the _Kseperator (which is the variable
returns on thousands_sep() ) to ',' if it is 0. The second constructor
leaves the variable to its old value =0. In the same file in VC7.1 the
if-statement in the first constructor doesn't exists.

I can't believe that this behaviour is no bug. Is their anyone who
knows something about this issue.