#if !defined WARN_IF_IGNORED_INCLUDED || defined WARN_IF_IGNORED_INCLUDED_TEMPLATE
#error      "warn_if_ignored-template.hpp" #included directly
#endif

#define      WARN_IF_IGNORED_INCLUDED_TEMPLATE   

#include <ios>
#include <iostream>

template<typename result_type>
warn_if_ignored<result_type>::warn_if_ignored(
    const result_type & decorated
)
    : result(decorated)
    , ignored(true)
{
    // all done
}

template<typename result_type>
warn_if_ignored<result_type>::warn_if_ignored(
    const warn_if_ignored & other
)
    : result(other.result)
    , ignored(other.ignored)
{
    other.ignored = false;
}
    
template<typename result_type>
warn_if_ignored<result_type>::~warn_if_ignored()
{
    if (ignored)
    {
        std::cerr << "WARNING: return " 
                  << result 
                  << "; is being ignored" 
                  << std::endl;
    }
}

template<typename result_type>
warn_if_ignored<result_type>::operator result_type () const 
{
    ignored = false;
    return result;
}