NAME
ares_mkquery - Compose a single-question DNS query buffer
SYNOPSIS
int ares_mkquery(const char *name, int dnsclass, int type,
unsigned short id, int rd, char **buf,
int *buflen)
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
R <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
R buf ,
and the length of which will be stored in the variable pointed to by
R buflen .
It is the caller's responsibility to free this buffer using
ares_free_string
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.
ARES_ENOMEM
Memory was exhausted.
SEE ALSO
AUTHOR
Greg Hudson, MIT Information Systems
Copyright 1998, 2000 by the Massachusetts Institute of Technology.
