NAME    [Toc]    [Back]

       res_search,  res_query  -  Query a domain server and check
       the response

SYNOPSIS    [Toc]    [Back]

       #include <sys/types.h>  #include  <netinet/in.h>  #include
       <arpa/nameser.h> #include <resolv.h>

       int res_search(
               const char *domain_name,
               int class,
               int type,
               u_char *answer,
               int answer_len );

       The res_query() syntax is as follows: int res_query(
               const char *domain_name,
               int class,
               int type,
               u_char *answer,
               int answer_len );

LIBRARY    [Toc]    [Back]

       Standard C Library (libc)

PARAMETERS    [Toc]    [Back]

       Points  to the fully-qualified name of the domain.  If the
       domain_name parameter points to a  single  label  and  the
       RES_DEFNAMES bit is set, as it is by default, the function
       appends domain_name to the current domain name.  The  current
  domain  name is defined by the name server in use or
       in the /etc/resolv.conf file.  Specifies one of  the  following
 parameters: Specifies the ARPA Internet.  Specifies
       the Chaos network at MIT.  Requires one of  the  following
       values: Host address Authoritative server Mail destination
       Mail forwarder Canonical  name  Start  of  authority  zone
       Mailbox  domain  name  Mail  group member Mail rename name
       NULL  resource  record  Well  known  service  Domain  name
       pointer  Host information Mailbox information Mail routing
       information User (finger) information  User  ID  Group  ID
       Points to a location of the server's reply.  Specifies the
       length of the answer pointed to by the answer parameter.

DESCRIPTION    [Toc]    [Back]

       The res_search() and  res_query()  functions  construct  a
       query,  send it to the local server, and await a response.
       In  addition,  res_search()  implements  the  default  and
       search  rules specified by the RES_DEFNAMES and RES_DNSRCH
       resolver options.  The function returns the first successful
 reply.

       The  res_search()  and res_query() functions part of a set
       of subroutines that form the resolver, a set of  functions
       that  resolve  domain  names.   Global information that is
       used by the resolver functions is kept in  the  _res  data
       structure.  The  /include/resolv.h  file contains the _res
       data structure definition.

RETURN VALUES    [Toc]    [Back]

       Upon  successful  completion,  the  res_search()  function
       returns  the  size  of the answer. If the answer is larger
       than the value of the answer_len parameter,  the  function
       fails and returns a value of -1.

ERRORS    [Toc]    [Back]

       If  an  error  occurs  during  a  resolver  operation, the
       h_errno external variable is set.  Error code  values  and
       reasons are defined in <netdb.h>.

FILES    [Toc]    [Back]

       Contains the name server and domain name.

SEE ALSO    [Toc]    [Back]

       Functions:  dn_comp(3), dn_expand(3), dn_find(3), dn_skipname(3),  _getlong(3),  _getshort(3),   putlong(3),   putshort(3),   res_init(3),   res_mkquery(3),   res_query(3),
       res_send(3).



                                                    res_search(3)