res_search()

The res_search() call makes a query and awaits a response.

Syntax

#include <sys\types.h>
#include <netinet\in.h>
#include <arpa\nameser.h>
#include <resolv.h>
int res_search(name, class, type, answer, anslen)
char *name;
int class;
int type;
u_char *answer;
int anslen;

Parameters

name

Points to the name of the domain. If the name parameter points to a single-component name and the RES_DEFNAMES structure is set, as it is by default, the call appends the default domain name to the single-component name. The current domain name is defined by the name server in use or is specified in the ETC\RESOLV file.

If the RES_DNSRCH bit is set, as it is by default, the res_search() call searches for host names in both the current domain and in parent domains.

Specifies one of the following values:

C_IN

Specifies the ARPA Internet.
C_CHAOS
Specifies the Chaos network at MIT.
type
Requires one of the following values:

T_A

Host address
T_NS
Authoritative server
T_MD
Mail destination
T_MF
Mail forwarder
T_CNAME
Canonical name
T_SOA
Start-of-authority zone
T_MB
Mailbox-domain name
T_MG
Mail-group member
T_MR
Mail-rename name
T_NULL
Null resource record
T_WKS
Well-known service
T_PTR
Domain name pointer
T_HINFO
Host information
T_MINFO
Mailbox information
T_MX
Mail-routing information
T_UINFO
User (finger command) information
T_UID
User ID
T_GID
Group ID
answer
Points to an address where the response is stored.
anslen
Specifies the size of the answer buffer.

Description

The res_search() call makes a query and awaits a response, like the res_query() call. However, it also implements the default and search rules controlled by the RES_DEFNAMES and RES_DNSRCH options.

Note: This call is only useful for queries in the same name hierarchy as the local host.

The res_search() call is one of a group of calls that form the resolver, a set of functions that resolve domain names. The _res data structure contains global information used by the resolver calls. The <RESOLV.H> file contains the _res structure definition. (See The _res Data Structure for more on the _res data structure.)

Return Values

When successful, the res_search() call returns the size of the response. When unsuccessful, the res_search() call returns a value of -1 and sets the h_errno value to the appropriate error.

Related Calls

dn_comp() dn_expand()
dn_find()
dn_skipname()


• getlong()
  
• getshort()
  putlong()
  putshort()
  res_init()
  res_mkquery()
  res_query()
  res_send()

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