ares_gethostbyaddr(3)

ARES_GETHOSTBYADDR(3)  C LIBRARY FUNCTIONS  ARES_GETHOSTBYADDR(3)

NAME

     ares_gethostbyaddr - Initiate a host query by address

SYNOPSIS

     #include <ares.h>

     typedef void (*ares_host_callback)(void *arg, int status,
          int timeouts, struct hostent *hostent)

     void ares_gethostbyaddr(ares_channel channel, const void *addr,
          int addrlen, int family, ares_host_callback callback,
          void *arg)

DESCRIPTION

     The ares_gethostbyaddr function initiates a  host  query  by
     address  on  the name service channel identified by channel.
     The parameters addr and addrlen give the address as a series
     of  bytes,  and  family gives the type of address.  When the
     query is complete or  has  failed,  the  ares  library  will
     invoke  callback.   Completion  or  failure of the query may
     happen immediately, or may happen during  a  later  call  to
     ares_process(3), ares_destroy(3) or ares_cancel(3).

     The   callback   argument   arg   is   copied    from    the
     ares_gethostbyaddr  argument  arg.   The  callback  argument
     status indicates whether the query succeeded  and,  if  not,
     how it failed.  It may have any of the following values:

     ARES_SUCCESS       The host lookup completed successfully.

     ARES_ENOTIMP       The ares library does  not  know  how  to
                        look up addresses of type family.

     ARES_ENOTFOUND     The address addr was not found.

     ARES_ENOMEM        Memory was exhausted.

     ARES_ECANCELLED    The query was cancelled.

     ARES_EDESTRUCTION  The name service channel channel is being
                        destroyed;  the  query  will  not be com-
                        pleted.

     The callback argument timeouts  reports  how  many  times  a
     query timed out during the execution of the given request.

     On successful completion of the query, the callback argument
     hostent  points  to  a struct hostent containing the name of
     the host returned by the query.  The callback need  not  and
     should not attempt to free the memory pointed to by hostent;
     the ares library will free it when the callback returns.  If
     the  query  did  not  complete successfully, hostent will be

                    Last change: 24 July 1998                   1

ARES_GETHOSTBYADDR(3)  C LIBRARY FUNCTIONS  ARES_GETHOSTBYADDR(3)

     NULL.

SEE ALSO

     ares_process(3), ares_gethostbyname(3)

AUTHOR

     Greg Hudson, MIT Information Systems
     Copyright 1998 by the Massachusetts Institute of Technology.

                    Last change: 24 July 1998                   2