NAME

res_send − Sends a query to a name server and retrieves a 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_send (
const u_char ∗msg_ptr,
int msg_len,
u_char ∗answer,
int ans_len );

PARAMETERS

msg_ptrPoints to the beginning of a message. 

msg_lenSpecifies the length of the message. 

answerPoints to an address where the response is stored. 

ans_lenSpecifies the size of the answer area. 

DESCRIPTION

The res_send() function sends a query to name servers and calls the res_init() function if the RES_INIT option of the _res data structure is not set.  This function sends the query to the local name server and handles timeouts and retries. 

The res_send() function is one 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_send() function returns the length of the message.  Otherwise, -1 is returned and the h_errno external variable is set with an error code, if any.  Error code values and reasons are defined in <netdb.h>. 

FILES

/etc/resolv.conf
Contains general name server and domain name information.

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_search(3).