HP-UX Reference (11i v3 07/02) - 3 Library Functions A-M (vol 6)

g
getaddrinfo(3N) getaddrinfo(3N)
In this case, if the hostname argument is a NULL pointer, then the IP address por-
tion of the socket address will be set to
loopback address.
If the
AI_CANONNAME bit is set, then upon successful return,
getaddrinfo()
will return the ai_canonname member of the first
addrinfo structure, which
is a NULL terminated string containing the canonical name of the specified host.
If an
AI_V4MAPPED flag is specified with an
ai_family value of AF_INET6,
getaddrinfo() returns IPv4-mapped IPv6 addresses when it does not find any
matching IPv6 addresses. getaddrinfo()
ignores an AI_V4MAPPED flag if
the
ai_family is not equal to AF_INET6.
If an AI_ALL flag is used with an
AI_V4MAPPED flag, getaddrinfo()
returns all the matching IPv6 and IPv4 addresses.
getaddrinfo()
ignores an
AI_ALL flag without an AI_V4MAPPED flag.
If an AI_ADDRCONFIG
flag is specified, then IPv4 addresses are returned only if
an IPv4 address is configured in the local system, and IPv6 addresses are returned
only if an IPv6 address is configured in the local system. In this case, the loopback
address is not considered as a valid configured address.
ai_family The protocol family the caller will accept. If this member is set to PF_UNSPEC ,
then the caller will accept any protocol family. If the caller handles only IPv4
stack and not IPv6 stack, then the
ai_family must be set to PF_INET.
ai_protocol The protocol the caller supports. If ai_protocol is set to 0, then the caller will
accept any protocol.
ai_socktype The socket type the caller supports. If ai_socktype is set to 0, then the caller
will accept any socket type. However, if the caller handles only TCP and not UDP,
then the ai_socktype must be set to SOCK_STREAM .
ai_addrlen The length, in bytes, of the IPv4 or IPv6 address.
ai_canonname The canonical name of the host.
ai_addr The binary address of the host.
ai_next The next addrinfo structure in the linked list.
The above argument is optional. If the caller wants to provide information such as the type of socket and
protocol family that the caller supports, the caller can specify them using the addrinfo structure. When
this information is passed to
getaddrinfo()
, all the fields other then ai_flags, ai_family,
ai_socktype , and ai_protocol must be set to zero or a NULL pointer.
When it returns successfully,
**res holds a pointer to a linked list of one or more addrinfo structures.
The caller can process each
addrinfo structure in this list by following the ai_next pointer, until a
NULL pointer is encountered. In each of the returned
addrinfo structures, the three members
ai_family, ai_socktype , and ai_protocol are used as arguments to the socket() function
call. The ai_addr member points to a socket address structure whose length is specified by the
ai_addrlen member.
The return value from the getaddrinfo() function is 0 upon success,oranonzero error code.
The following are the nonzero error codes given by getaddrinfo(). These are defined in <netdb.h> :
EAI_ADDRFAMILY Address family for hostname not supported.
EAI_AGAIN Temporary failure in name resolution.
EAI_BADFLAGS Invalid value for ai_flags.
EAI_FAIL Non-recoverable failure in name resolution.
EAI_OVERFLOW Argument buffer overflow
EAI_FAMILY ai_family not supported.
EAI_MEMORY Memory allocation failure.
EAI_NODATA No address associated with hostname.
EAI_NONAME No hostname nor servname provided, or not known.
HP-UX 11i Version 3: February 2007 − 2 − Hewlett-Packard Company 489