std::ios_base::failure

class ios_base::failure : public exception {
public:
  explicit failure (const string& msg);
  virtual ~failure();
  virtual const char* what() const throw();
}

class ios_base::failure : public system_error {
public:
  explicit failure (const string& msg, const error_code& ec = io_errc::stream);
  explicit failure (const char*   msg, const error_code& ec = io_errc::stream);
}