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ARES_MKQUERY(3) Library Functions Manual ARES_MKQUERY(3)


ares_mkquery - Compose a single-question DNS query buffer


#include <ares.h>
int ares_mkquery(const char *name, int dnsclass, int type,

unsigned short id, int rd, unsigned char **buf,
int *buflen)


Deprecated function. See ares_create_query(3) instead!

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.

Usage of ares_mkquery(3) is deprecated, whereas the function is equivalent to ares_create_query(3) with max_udp_size set to 0.


ares_mkquery can return any of the following values:

Construction of the DNS query succeeded.
The query name name refers to a .onion domain name. See RFC 7686.
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.
Memory was exhausted.


ares_expand_name(3), ares_dns_record(3), ares_free_string(3)


Greg Hudson, MIT Information Systems
Copyright 1998, 2000 by the Massachusetts Institute of Technology.

20 Nov 2009