1ARES_PROCESS(3)            Library Functions Manual            ARES_PROCESS(3)
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NAME

6       ares_process - Process events for name resolution
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SYNOPSIS

9       #include <ares.h>
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11       void ares_process(ares_channel channel,
12                         fd_set *read_fds,
13                         fd_set *write_fds)
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15       void ares_process_fd(ares_channel channel,
16                            ares_socket_t read_fd,
17                            ares_socket_t write_fd)
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DESCRIPTION

20       The  ares_process(3)  function handles input/output events and timeouts
21       associated with queries pending on the name service channel  identified
22       by  channel.   The  file  descriptor  sets  pointed  to by read_fds and
23       write_fds should have file descriptors set in them according to whether
24       the file descriptors specified by ares_fds(3) are ready for reading and
25       writing.  (The easiest way to determine this information is  to  invoke
26       select(3)  with  a  timeout  no  greater  than  the  timeout  given  by
27       ares_timeout(3)).
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29       The ares_process(3) function will invoke callbacks for pending  queries
30       if they complete successfully or fail.
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32       ares_process_fd(3) works the same way but acts and operates only on the
33       specific file descriptors (sockets) you pass in to  the  function.  Use
34       ARES_SOCKET_BAD  for  "no  action".  This function is provided to allow
35       users of c-ares to avoid select(3) in their applications and within  c-
36       ares.
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38       To  only process possible timeout conditions without a socket event oc‐
39       curring, one may  pass  NULL  as  the  values  for  both  read_fds  and
40       write_fds  for ares_process(3), or ARES_SOCKET_BAD for both read_fd and
41       write_fd for ares_process_fd(3).
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EXAMPLE

44       The following code fragment waits for all pending queries on a  channel
45       to complete:
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47       int nfds, count;
48       fd_set readers, writers;
49       struct timeval tv, *tvp;
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51       while (1) {
52         FD_ZERO(&readers);
53         FD_ZERO(&writers);
54         nfds = ares_fds(channel, &readers, &writers);
55         if (nfds == 0)
56           break;
57         tvp = ares_timeout(channel, NULL, &tv);
58         count = select(nfds, &readers, &writers, NULL, tvp);
59         ares_process(channel, &readers, &writers);
60       }
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SEE ALSO

63       ares_fds(3), ares_timeout(3)
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AUTHOR

66       Greg Hudson, MIT Information Systems
67       Copyright 1998 by the Massachusetts Institute of Technology.
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71                                 25 July 1998                  ARES_PROCESS(3)