NAME

       ares_create_query - Compose a single-question DNS query buffer

SYNOPSIS

       #include <ares.h>

       int ares_create_query(const char *name,
                             int dnsclass,
                             int type,
                             unsigned short id,
                             int rd,
                             unsigned char **buf,
                             int *buflen,
                             int max_udp_size)

DESCRIPTION

       The  ares_create_query(3)  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.  The parameter max_udp_size should be nonzero to activate EDNS. Usage of
       ares_create_query(3) with max_udp_size set to zero is equivalent to using ares_mkquery(3).

RETURN VALUES

       ares_create_query 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.

AVAILABILITY

       Added in c-ares 1.10.0

SEE ALSO

       ares_expand_name(3), ares_free_string(3), ares_mkquery(3)

AUTHOR

                                           17 Aug 2012                       ARES_CREATE_QUERY(3)