NAME

SYNOPSIS

DESCRIPTION

struct addrinfo {
	int ai_flags;		/* input flags */
	int ai_family;		/* protocol family for socket */
	int ai_socktype;	/* socket type */
	int ai_protocol;	/* protocol for socket */
	socklen_t ai_addrlen;	/* length of socket-address */
	struct sockaddr *ai_addr; /* socket-address for socket */
	char *ai_canonname;	/* canonical name for service location */
	struct addrinfo *ai_next; /* pointer to next in list */
};

ai_family

The protocol family that should be used. When ai_family is set to PF_UNSPEC, it means the caller will accept any protocol family supported by the operating system.

ai_socktype

Denotes the type of socket that is wanted: SOCK_STREAM, SOCK_DGRAM, or SOCK_RAW. When ai_socktype is zero the caller will accept any socket type.

ai_protocol

Indicates which transport protocol is desired, IPPROTO_UDP or IPPROTO_TCP. If ai_protocol is zero the caller will accept any protocol.

ai_flags

ai_flags is formed by OR the following values:

AI_CANONNAME

If the AI_CANONNAME bit is set, a successful call to getaddrinfo(); will return a NUL-terminated string containing the canonical name of the specified hostname in the ai_canonname element of the first addrinfo structure returned.

AI_NUMERICHOST

If the AI_NUMERICHOST bit is set, it indicates that hostname should be treated as a numeric string defining an IPv4 or IPv6 address and no name resolution should be attempted.

AI_NUMERICSERV

If the AI_NUMERICSERV bit is set, it indicates that servname should be treated as a numeric port string and no service name resolution should be attempted.

AI_PASSIVE

If the AI_PASSIVE bit is set it indicates that the returned socket address structure is intended for use in a call to bind(2). In this case, if the hostname argument is the null pointer, then the IP address portion of the socket address structure will be set to INADDR_ANY for an IPv4 address or IN6ADDR_ANY_INIT for an IPv6 address.

If the AI_PASSIVE bit is not set, the returned socket address structure will be ready for use in a call to connect(2) for a connection-oriented protocol or connect(2), sendto(2), or sendmsg(2) if a connectionless protocol was chosen. The IP address portion of the socket address structure will be set to the loopback address if hostname is the null pointer and AI_PASSIVE is not set.

RETURN VALUES

EXAMPLES

struct addrinfo hints, *res, *res0;
int error;
int save_errno;
int s;
const char *cause = NULL;

memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
error = getaddrinfo("www.kame.net", "www", &hints, &res0);
if (error)
	errx(1, "%s", gai_strerror(error));
s = -1;
for (res = res0; res; res = res->ai_next) {
	s = socket(res->ai_family, res->ai_socktype,
	    res->ai_protocol);
	if (s == -1) {
		cause = "socket";
		continue;
	}

	if (connect(s, res->ai_addr, res->ai_addrlen) == -1) {
		cause = "connect";
		save_errno = errno;
		close(s);
		errno = save_errno;
		s = -1;
		continue;
	}

	break;	/* okay we got one */
}
if (s == -1)
	err(1, "%s", cause);
freeaddrinfo(res0);

struct addrinfo hints, *res, *res0;
int error;
int save_errno;
int s[MAXSOCK];
int nsock;
const char *cause = NULL;

memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_PASSIVE;
error = getaddrinfo(NULL, "www", &hints, &res0);
if (error)
	errx(1, "%s", gai_strerror(error));
nsock = 0;
for (res = res0; res && nsock < MAXSOCK; res = res->ai_next) {
	s[nsock] = socket(res->ai_family, res->ai_socktype,
	    res->ai_protocol);
	if (s[nsock] == -1) {
		cause = "socket";
		continue;
	}

	if (bind(s[nsock], res->ai_addr, res->ai_addrlen) == -1) {
		cause = "bind";
		save_errno = errno;
		close(s[nsock]);
		errno = save_errno;
		continue;
	}
	(void) listen(s[nsock], 5);

	nsock++;
}
if (nsock == 0)
	err(1, "%s", cause);
freeaddrinfo(res0);

SEE ALSO

STANDARDS

BUGS