examples/manual/has_facet.cpp

/**************************************************************************
 *
 * hasfacet.cpp - Example program of the hasfacet function template. 
 *
 * $Id$
 *
 ***************************************************************************
 *
 * Copyright (c) 1994-2005 Quovadx,  Inc., acting through its  Rogue Wave
 * Software division. Licensed under the Apache License, Version 2.0 (the
 * "License");  you may  not use this file except  in compliance with the
 * License.    You    may   obtain   a   copy   of    the   License    at
 * http://www.apache.org/licenses/LICENSE-2.0.    Unless   required    by
 * applicable law  or agreed to  in writing,  software  distributed under
 * the License is distributed on an "AS IS" BASIS,  WITHOUT WARRANTIES OR
 * CONDITIONS OF  ANY KIND, either  express or implied.  See  the License
 * for the specific language governing permissions  and limitations under
 * the License.
 * 
 **************************************************************************/

#include <ios>        // for boolalpha 
#include <iostream>   // for cout
#include <locale>     // for ctype, has_facet(), locale

#include <examples.h>


// dummy facet, must derive from locale::facet
// and define a static member of type locale::id
struct MyFacet: public std::locale::facet
{
    static std::locale::id id;
};

std::locale::id MyFacet::id;


int main ()
{
    // create a copy of the locale imbued in cout
    const std::locale loc (std::cout.getloc ());

    std::cout << std::boolalpha
              << "std::has_facet<std::ctype<char> >(std::cout.getloc ()) = ";

    // see if ctype<char> is installed in the locale (expect true)
    std::cout << std::has_facet<std::ctype<char> >(loc) << '\n';
 
    std::cout << "std::has_facet<MyFacet>(std::cout.getloc ()) = ";

    // see if MyFacet is installed in the locale (expect false)
    std::cout << std::has_facet<MyFacet>(loc) << '\n';

    return 0;
}