1ARES_CREATE_QUERY(3) Library Functions Manual ARES_CREATE_QUERY(3)
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6 ares_create_query - Compose a single-question DNS query buffer
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9 #include <ares.h>
10 int ares_create_query(const char *name, int dnsclass, int type,
12 unsigned short id, int rd, unsigned char **buf,
13 int *buflen, int max_udp_size)
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16 The ares_create_query function composes a DNS query with a single ques‐
17 tion. The parameter name gives the query name as a NUL-terminated C
18 string of period-separated labels optionally ending with a period;
19 periods and backslashes within a label must be escaped with a backlash.
20 The parameters dnsclass and type give the class and type of the query
21 using the values defined in <arpa/nameser.h>. The parameter id gives a
22 16-bit identifier for the query. The parameter rd should be nonzero if
23 recursion is desired, zero if not. The query will be placed in an
24 allocated buffer, a pointer to which will be stored in the variable
25 pointed to by buf, and the length of which will be stored in the vari‐
26 able pointed to by buflen. It is the caller's responsibility to free
27 this buffer using ares_free_string(3) when it is no longer needed. The
28 parameter max_udp_size should be nonzero to activate EDNS. Usage of
29 ares_create_query(3) with max_udp_size set to zero is equivalent to
30 ares_mkquery(3).
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33 ares_create_query can return any of the following values:
34 ARES_SUCCESS Construction of the DNS query succeeded.
36 ARES_EBADNAME The query name name could not be encoded as a domain
38 name, either because it contained a zero-length label or
39 because it contained a label of more than 63 characters.
40 ARES_ENOMEM Memory was exhausted.
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44 Added in c-ares 1.10.0
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47 ares_expand_name(3), ares_free_string(3)
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50 17 Aug 2012 ARES_CREATE_QUERY(3)