namespace
boost
    {
    template <class ErrorInfo,class E>
    typename ErrorInfo::error_info::value_type const * get_error_info( E const & x );
    
    template <class ErrorInfo,class E>
    typename ErrorInfo::error_info::value_type * get_error_info( E & x );
    }
Nothing.
The interface of get_error_info may be affected by the build configuration macros.