ares_create_query(3)

ARES_CREATE_QUERY(3)   C LIBRARY FUNCTIONS   ARES_CREATE_QUERY(3)

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 param-
     eter 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.

                    Last change: 17 Aug 2012                    1

ARES_CREATE_QUERY(3)   C LIBRARY FUNCTIONS   ARES_CREATE_QUERY(3)

     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

                    Last change: 17 Aug 2012                    2