char *addr, ssize_t addrlen, int32_t *netmask);
extern char *parse_url(const char *url,
char *host, ssize_t hostlen, int32_t *port);
+char *format_url(const char *url, int default_port);
extern const char *stringify_port(int port, const char *transport);
/**
* Ensure that string conforms to the IPv4 address format.