+ * opt_register_noarg("--help|--usage|-h", opt_usage_and_exit,
+ * "\nA oserver program", "Usage information");
+ * opt_register_arg("--port", opt_set_uintval, opt_show_uintval,
+ * &port, "Server port number");
+ *
+ * opt_parse(&argc, argv, opt_log_stderr_exit);
+ * if (argc != 1)
+ * opt_log_stderr_exit("Unknown extra arguments");
+ *
+ * sockfd = oserver_setup(port);