Function value_help

extern/boost/boost/test/utils/runtime/parameter.hpp:401–407

        ostr << cla_tag;
    }
    void    value_help( std::ostream& ostr ) const BOOST_OVERRIDE
    {
        if( p_value_hint.empty() )
            ostr << "<boolean value>";
        else
            ostr << p_value_hint;
    }

    // Data members
    typedef argument_factory<bool, false, false> factory_t;