1ARES_SEARCH(3) Library Functions Manual ARES_SEARCH(3)
2
6 ares_search - Initiate a DNS query with domain search
7
9 #include <ares.h>
10 typedef void (*ares_callback)(void *arg, int status,
12 unsigned char *abuf, int alen)
13 void ares_search(ares_channel channel, const char *name,
15 int dnsclass, int type, ares_callback callback,
16 void *arg)
17
19 The ares_search function initiates a series of single-question DNS
20 queries on the name service channel identified by channel, using the
21 channel's search domains as well as a host alias file given by the
22 HOSTALIAS environment variable. The parameter name gives the alias
23 name or the base of the query name as a NUL-terminated C string of
24 period-separated labels; if it ends with a period, the channel's search
25 domains will not be used. Periods and backslashes within a label must
26 be escaped with a backslash. The parameters dnsclass and type give the
27 class and type of the query using the values defined in
28 <arpa/nameser.h>. When the query sequence is complete or has failed,
29 the ares library will invoke callback. Completion or failure of the
30 query sequence may happen immediately, or may happen during a later
31 call to ares_process(3) or ares_destroy(3).
32 The callback argument arg is copied from the ares_search argument arg.
34 The callback argument status indicates whether the query sequence ended
35 with a successful query and, if not, how the query sequence failed. It
36 may have any of the following values:
37 ARES_SUCCESS A query completed successfully.
39 ARES_ENODATA No query completed successfully; when the query was
41 tried without a search domain appended, a response
42 was returned with no answers.
43 ARES_EFORMERR A query completed but the server claimed that the
45 query was malformatted.
46 ARES_ESERVFAIL No query completed successfully; when the query was
48 tried without a search domain appended, the server
49 claimed to have experienced a failure. (This code
50 can only occur if the ARES_FLAG_NOCHECKRESP flag was
51 specified at channel initialization time; otherwise,
52 such responses are ignored at the ares_send(3)
53 level.)
54 ARES_ENOTFOUND No query completed successfully; when the query was
56 tried without a search domain appended, the server
57 reported that the queried-for domain name was not
58 found.
59 ARES_ENOTIMP A query completed but the server does not implement
61 the operation requested by the query. (This code
62 can only occur if the ARES_FLAG_NOCHECKRESP flag was
63 specified at channel initialization time; otherwise,
64 such responses are ignored at the ares_send(3)
65 level.)
66 ARES_EREFUSED A query completed but the server refused the query.
68 (This code can only occur returned if the
69 ARES_FLAG_NOCHECKRESP flag was specified at channel
70 initialization time; otherwise, such responses are
71 ignored at the ares_send(3) level.)
72 ARES_TIMEOUT No name servers responded to a query within the
74 timeout period.
75 ARES_ECONNREFUSED No name servers could be contacted.
77 ARES_ENOMEM Memory was exhausted.
79 ARES_EDESTRUCTION The name service channel channel is being destroyed;
81 the query will not be completed.
82 If a query completed successfully, the callback argument abuf points to
84 a result buffer of length alen. If the query did not complete successâ
85 fully, abuf will usually be NULL and alen will usually be 0, but in
86 some cases an unsuccessful query result may be placed in abuf.
87
89 ares_process(3)
90
92 Greg Hudson, MIT Information Systems
93 Copyright 1998 by the Massachusetts Institute of Technology.
94 24 July 1998 ARES_SEARCH(3)