odr.hpp

[2005最新C++经典著作].C++ Programming.新手必看的学VC的奠基之著。

// Copyright (C) 2004 Arkadiy Vertleyb
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (http://www.boost.org/LICENSE_1_0.txt)

#ifndef ODR_HPP_INCLUDED
#define ODR_HPP_INCLUDED

#include <boost/spirit/typeof/typeof.hpp>

void odr_test1();
void odr_test2();

// trying to cause ODR violation in a class template

template<class T, class U>
class sum_t
{
public:
    typedef BOOST_TYPEOF_TPL(T() + U()) result_type;

    sum_t(const T& t, const U& u)
        : m_sum(t + u)
    {}
    BOOST_TYPEOF_TPL(T() + U()) operator()()
    {
        BOOST_AUTO_TPL(result, m_sum);
        return result;
    }
private:
    BOOST_TYPEOF_TPL(T() + U()) m_sum;
};

template<class T, class U>
sum_t<T, U> make_sum(const T& t, const U& u)
{
    return sum_t<T, U>(t, u);
}

// trying to cause ODR violation in a function template

template<class T, class U>
typename sum_t<T, U>::result_type sum(const T& t, const U& u)
{
    BOOST_AUTO_TPL(result, t + u);
    return result;
}

#endif//ODR_HPP_INCLUDED