error_code make_error_code(errc e) noexcept;
Returns: error_code(static_cast<int>(e), generic_category()).
bool operator<(const error_code& lhs, const error_code& rhs) noexcept;
Returns: lhs.category() < rhs.category() || lhs.category() == rhs.category() && lhs.value() < rhs.value().
template <class charT, class traits>
basic_ostream<charT,traits>&
operator<<(basic_ostream<charT,traits>& os, const error_code& ec);
Effects: os << ec.category().name() << ':' << ec.value().