On Apache/1.3.41 (Unix) PHP/5.2.5 mod_perl/1.30 mod_gzip/1.3.26.1a
Under GNU General Public License
2009-01-09 06:40 @38.103.63.58 CrawledBy CCBot/1.0 (+http://www.commoncrawl.org/bot.html)
getaddrinfo(3) Linux Programmer’s Manual getaddrinfo(3)
NAME
getaddrinfo, freeaddrinfo, gai_strerror - network address and service translation
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
int getaddrinfo(const char *node, const char *service,
const struct addrinfo *hints,
struct addrinfo **res);
void freeaddrinfo(struct addrinfo *res);
const char *gai_strerror(int errcode);
DESCRIPTION
The getaddrinfo(3) function combines the functionality provided by the getipnodeby-
name(3), getipnodebyaddr(3), getservbyname(3), and getservbyport(3) functions into
a single interface. The thread-safe getaddrinfo(3) function creates one or more
socket address structures that can be used by the bind(2) and connect(2) system
calls to create a client or a server socket.
The getaddrinfo(3) function is not limited to creating IPv4 socket address struc-
tures; IPv6 socket address structures can be created if IPv6 support is available.
These socket address structures can be used directly by bind(2) or connect(2), to
prepare a client or a server socket.
The addrinfo structure used by this function contains the following members:
struct addrinfo {
int ai_flags;
int ai_family;
int ai_socktype;
int ai_protocol;
size_t ai_addrlen;
struct sockaddr *ai_addr;
char *ai_canonname;
struct addrinfo *ai_next;
};
getaddrinfo(3) sets res to point to a dynamically-allocated link list of addrinfo
structures, linked by the ai_next member. There are several reasons why the link
list may have more than one addrinfo structure, including: if the network host is
multi-homed; or if the same service is available from multiple socket protocols
(one SOCK_STREAM address and another SOCK_DGRAM address, for example).
The members ai_family, ai_socktype, and ai_protocol have the same meaning as the
corresponding parameters in the socket(2) system call. The getaddrinfo(3) function
returns socket addresses in either IPv4 or IPv6 address family, (ai_family will be
set to either PF_INET or PF_INET6).
The hints parameter specifies the preferred socket type, or protocol. A NULL hints
specifies that any network address or protocol is acceptable. If this parameter is
not NULL it points to an addrinfo structure whose ai_family, ai_socktype, and
ai_protocol members specify the preferred socket type. PF_UNSPEC in ai_family
specifies any protocol family (either IPv4 or IPv6, for example). 0 in ai_socktype
or ai_protocol specifies that any socket type or protocol is acceptable as well.
The ai_flags member specifies additional options, defined below. Multiple flags
are specified by logically OR-ing them together. All the other members in the
hints parameter must contain either 0, or a null pointer.
The node or service parameter, but not both, may be NULL. node specifies either a
numerical network address (dotted-decimal format for IPv4, hexadecimal format for
IPv6) or a network hostname, whose network addresses are looked up and resolved.
If the ai_flags member in the hints parameter contains the AI_NUMERICHOST flag then
the node parameter must be a numerical network address. The AI_NUMERICHOST flag
suppresses any potentially lengthy network host address lookups.
The getaddrinfo(3) function creates a link list of addrinfo structures, one for
each network address subject to any restrictions imposed by the hints parameter.
ai_canonname is set to point to the official name of the host, if ai_flags in hints
includes the AI_CANONNAME flag. ai_family, ai_socktype, and ai_protocol specify
the socket creation parameters. A pointer to the socket address is placed in the
ai_addr member, and the length of the socket address, in bytes, is placed in the
ai_addrlen member.
If node is NULL, the network address in each socket structure is initialized
according to the AI_PASSIVE flag, which is set in the ai_flags member of the hints
parameter. The network address in each socket structure will be left unspecified
if AI_PASSIVE flag is set. This is used by server applications, which intend to
accept client connections on any network address. The network address will be set
to the loopback interface address if the AI_PASSIVE flag is not set. This is used
by client applications, which intend to connect to a server running on the same
network host.
service sets the port number in the network address of each socket structure. If
service is NULL the port number will be left uninitialized.
The freeaddrinfo(3) function frees the memory that was allocated for the dynami-
cally allocated link list res.
RETURN VALUE
getaddrinfo(3) returns 0 if it succeeds, or one of the following non-zero error
codes:
EAI_FAMILY
The requested address family is not supported at all.
EAI_SOCKTYPE
The requested socket type is not supported at all.
EAI_BADFLAGS
ai_flags contains invalid flags.
EAI_NONAME
The node or service is not known. This error is also returned if both node
and service are NULL.
EAI_SERVICE
The requested service is not available for the requested socket type. It
may be available through another socket type.
EAI_ADDRFAMILY
The specified network host does not have any network addresses in the
requested address family.
EAI_NODATA
The specified network host exists, but does not have any network addresses
defined.
EAI_MEMORY
Out of memory.
EAI_FAIL
The name server returned a permanent failure indication.
EAI_AGAIN
The name server returned a temporary failure indication. Try again later.
EAI_SYSTEM
Other system error, check errno for details.
The gai_strerror(3) function translates these error codes to a human readable
string, suitable for error reporting.
CONFORMING TO
POSIX 1003.1-2003. The getaddrinfo() function is documented in RFC 2553.
SEE ALSO
getipnodebyname(3), getipnodebyaddr(3)
Linux Man Page 2000-12-18 getaddrinfo(3)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache/1.3.41 (Unix) PHP/5.2.5 mod_perl/1.30 mod_gzip/1.3.26.1a
Under GNU General Public License
2009-01-09 06:40 @38.103.63.58 CrawledBy CCBot/1.0 (+http://www.commoncrawl.org/bot.html)