Function report_error_code

example/error_demo.cpp:77–84

  }

  void report_error_code(const error_code& ec)
  {
    cout << "  ec:\n"
         << "    value() is " << ec.value() << '\n'
         << "    category().name() is " << ec.category().name() << '\n'
         << "    message() is " <<  ec.message() << '\n'
         ;
  }

  bool threw_exception;