Change of the locale

[GiuspeCar]

First of all, I'm sorry for my English.
I'm trying to change the locale in a C++ program to put accented letters in a wchar_t variables and viewed it on terminal, as here reported:

#include "iostream"
#include "locale"
using namespace std;


int main()
{


     setlocale (LC_ALL," ");
     locale loc;
     loc= locale("INVARIANT");
     wcin.imbue(loc);
     wcout.imbue(loc);


    cout<<"locale : "<< loc.name() <<endl;

wchar_t a;
wcin >> a ;
wcout << a;

}

The cout is: " terminate called after throwing an instance of 'std::runtime_error'
what(): locale::facet::_S_create_c_locale name not valid
Annullato (core dump creato) "

If I change the arguments of setlocale and locale in, respectively, " NULL" 'n "POSIX", the program is compiled and cout is:
" locale : C
à"
the "à" is variable of wcin, but there isn't wcout.

How can i resolve it?

P.S. I use Korora 64-bit on xfce, xfce terminal with UTF-8 like charset