getipnodebyaddr(3)



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

NAME
       getipnodebyname,  getipnodebyaddr, freehostent - get network host names
       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. Use getaddrinfo(3)  and  getnameinfo(3)
       instead.

       The  getipnodebyname(3)  and  getipnodebyaddr(3)  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) func-
       tions, which could only access the IPv4 network  address  family.   The
       getipnodebyname(3) and getipnodebyaddr(3) functions can access multiple
       network address families.

       Unlike the gethostby functions,  these  functions  return  pointers  to
       dynamically  allocated  memory.  The freehostent(3) function is used to
       release the dynamically allocated memory after  the  caller  no  longer
       needs the hostent structure.

   getipnodebyname parameters
       The getipnodebyname(3) function looks up network addresses for the host
       specified by the name parameter.  The af parameter specifies one of the
       following values:

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

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

       The flags parameter specifies additional options.  More than one option
       can be specified by logically 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 parameters
       The getipnodebyaddr(3) function looks up the name  of  the  host  whose
       network  address  is specified by the addr parameter.  The af parameter
       specifies one of the following values:

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

       AF_INET6
              The  addr  parameter 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 host name 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 better luck next time.

       A  successful  query returns a pointer to a hostent structure that con-
       tains 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 parameter to getipnodebyname(3) or
              getipnodebyaddr(3).  h_addrtype will always be AF_INET if the af
              parameter  was  AF_INET.   h_addrtype will always be AF_INET6 if
              the af parameter 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 network host.  The array is terminated by a
              null pointer.

NOTES
       These functions have been present in glibc 2.1.91-95, but were  removed
       again. Several Unix-like systems support them, but all call them depre-
       cated.

CONFORMING TO
       RFC 2553.

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

Linux Man Page                    2002-04-03                getipnodebyname(3)

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