NAME

res_send − Send a query to a name server and retrieve a response

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 );

LIBRARY

Standard C Library (libc)

PARAMETERS

msg_ptr
Points to the beginning of a message.

msg_len
Specifies the length of the message.

answer
Points to an address where the response is stored.

ans_len
Specifies 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 _resdata 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.

SEE ALSO

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).