Section: C Library Functions (3)Updated: 20 Nov 2009Local indexUp
NAME
ares_mkquery - Compose a single-question DNS query buffer
SYNOPSIS
#include <ares.h>int ares_mkquery(const char *name, int dnsclass, int type,
DESCRIPTION
The
ares_mkquery
function composes a DNS query with a single question.
The parameter
name
gives the query name as a NUL-terminated C string of period-separated
labels optionally ending with a period; periods and backslashes within
a label must be escaped with a backlash. The parameters
dnsclass
and
type
give the class and type of the query using the values defined in
<arpa/nameser.h>.
The parameter
id
gives a 16-bit identifier for the query. The parameter
rd
should be nonzero if recursion is desired, zero if not. The query
will be placed in an allocated buffer, a pointer to which will be
stored in the variable pointed to by
buf,
and the length of which will be stored in the variable pointed to by
buflen.
It is the caller's responsibility to free this buffer using
ares_free_string(3) when it is no longer needed.
RETURN VALUES
ares_mkquery
can return any of the following values:
ARES_SUCCESS
Construction of the DNS query succeeded.
ARES_EBADNAME
The query name
name
could not be encoded as a domain name, either because it contained a
zero-length label or because it contained a label of more than 63
characters.