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Linux 2.6 - man page for getipnodebyaddr (linux section 3)

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GETIPNODEBYNAME(3)		    Linux Programmer's Manual		       GETIPNODEBYNAME(3)

NAME
       getipnodebyname, getipnodebyaddr, freehostent - get network hostnames and addresses

SYNOPSIS
       #include <sys/types.h>
       #include <sys/socket.h>
       #include <netdb.h>

       struct hostent *getipnodebyname(const char *name, int af,
				       int flags, int *error_num);

       struct hostent *getipnodebyaddr(const void *addr, size_t len,
				       int af, int *error_num);

       void freehostent(struct hostent *ip);

DESCRIPTION
       These  functions  are  deprecated (and unavailable in glibc).  Use getaddrinfo(3) and get-
       nameinfo(3) instead.

       The getipnodebyname() and getipnodebyaddr() functions return the names and addresses of	a
       network host.  These functions return a pointer to the following structure:

	   struct hostent {
	       char  *h_name;
	       char **h_aliases;
	       int    h_addrtype;
	       int    h_length;
	       char **h_addr_list;
	   };

       These  functions  replace the gethostbyname(3) and gethostbyaddr(3) functions, which could
       access only the IPv4 network address family.  The getipnodebyname() and	getipnodebyaddr()
       functions can access multiple network address families.

       Unlike  the  gethostby functions, these functions return pointers to dynamically allocated
       memory.	The freehostent() function is used to release the  dynamically	allocated  memory
       after the caller no longer needs the hostent structure.

   getipnodebyname() arguments
       The  getipnodebyname()  function  looks up network addresses for the host specified by the
       name argument.  The af argument specifies one of the following values:

       AF_INET
	      The name argument points to a dotted-quad IPv4 address or a name of an IPv4 network
	      host.

       AF_INET6
	      The name argument points to a hexadecimal IPv6 address or a name of an IPv6 network
	      host.

       The flags argument specifies additional options.  More than one option can be specified by
       bitwise OR-ing them together.  flags should be set to 0 if no options are desired.

       AI_V4MAPPED
	      This  flag  is  used with AF_INET6 to request a query for IPv4 addresses instead of
	      IPv6 addresses; the IPv4 addresses will be mapped to IPv6 addresses.

       AI_ALL This flag is used with AI_V4MAPPED to request  a	query  for  both  IPv4	and  IPv6
	      addresses.  Any IPv4 address found will be mapped to an IPv6 address.

       AI_ADDRCONFIG
	      This  flag is used with AF_INET6 to further request that queries for IPv6 addresses
	      should not be made unless the system has at least one IPv6 address  assigned  to	a
	      network  interface,  and	that queries for IPv4 addresses should not be made unless
	      the system has at least one IPv4 address assigned to  a  network	interface.   This
	      flag may be used by itself or with the AI_V4MAPPED flag.

       AI_DEFAULT
	      This flag is equivalent to (AI_ADDRCONFIG | AI_V4MAPPED).

   getipnodebyaddr() arguments
       The  getipnodebyaddr()  function  looks	up  the name of the host whose network address is
       specified by the addr argument.	The af argument specifies one of the following values:

       AF_INET
	      The addr argument points to a struct in_addr and len must be set	to  sizeof(struct
	      in_addr).

       AF_INET6
	      The  addr argument points to a struct in6_addr and len must be set to sizeof(struct
	      in6_addr).

RETURN VALUE
       A NULL pointer is returned if an error occurred, and error_num will contain an error  code
       from the following list:

       HOST_NOT_FOUND
	      The hostname or network address was not found.

       NO_ADDRESS
	      The  domain  name  server recognized the network address or name, but no answer was
	      returned.  This can happen if the network  host  has  only  IPv4	addresses  and	a
	      request has been made for IPv6 information only, or vice versa.

       NO_RECOVERY
	      The domain name server returned a permanent failure response.

       TRY_AGAIN
	      The  domain name server returned a temporary failure response.  You might have bet-
	      ter luck next time.

       A successful query returns a pointer to a hostent structure that  contains  the	following
       fields:

       h_name This is the official name of this network host.

       h_aliases
	      This is an array of pointers to unofficial aliases for the same host.  The array is
	      terminated by a NULL pointer.

       h_addrtype
	      This is a copy of  the  af  argument  to	getipnodebyname()  or  getipnodebyaddr().
	      h_addrtype  will always be AF_INET if the af argument was AF_INET.  h_addrtype will
	      always be AF_INET6 if the af argument was AF_INET6.

       h_length
	      This field will be set to sizeof(struct in_addr) if h_addrtype is AF_INET,  and  to
	      sizeof(struct in6_addr) if h_addrtype is AF_INET6.

       h_addr_list
	      This is an array of one or more pointers to network address structures for the net-
	      work host.  The array is terminated by a NULL pointer.

CONFORMING TO
       RFC 2553.

NOTES
       These functions were present in glibc 2.1.91-95, but were removed  again.   Several  UNIX-
       like systems support them, but all call them deprecated.

SEE ALSO
       getaddrinfo(3), getnameinfo(3), inet_ntop(3), inet_pton(3)

COLOPHON
       This  page  is  part of release 3.55 of the Linux man-pages project.  A description of the
       project,    and	  information	 about	  reporting    bugs,	can    be    found     at
       http://www.kernel.org/doc/man-pages/.

Linux					    2010-09-04			       GETIPNODEBYNAME(3)
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