res_search(3) Library Functions Manual res_search(3)
NAME
res_search, res_query - Queries domain server and checks response
LIBRARY
Standard C Library (libc.a, libc.so)
SYNOPSIS
#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;)
PARAMETERS
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
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 suc-
cessful 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
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
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
Contains the name server and domain name.
RELATED INFORMATION
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). delim off
res_search(3)