| 1 | .\" $Id: ares_process.3,v 1.2 1998-08-20 23:21:03 ghudson Exp $ |
|---|
| 2 | .\" |
|---|
| 3 | .\" Copyright 1998 by the Massachusetts Institute of Technology. |
|---|
| 4 | .\" |
|---|
| 5 | .\" Permission to use, copy, modify, and distribute this |
|---|
| 6 | .\" software and its documentation for any purpose and without |
|---|
| 7 | .\" fee is hereby granted, provided that the above copyright |
|---|
| 8 | .\" notice appear in all copies and that both that copyright |
|---|
| 9 | .\" notice and this permission notice appear in supporting |
|---|
| 10 | .\" documentation, and that the name of M.I.T. not be used in |
|---|
| 11 | .\" advertising or publicity pertaining to distribution of the |
|---|
| 12 | .\" software without specific, written prior permission. |
|---|
| 13 | .\" M.I.T. makes no representations about the suitability of |
|---|
| 14 | .\" this software for any purpose. It is provided "as is" |
|---|
| 15 | .\" without express or implied warranty. |
|---|
| 16 | .\" |
|---|
| 17 | .TH ARES_PROCESS 3 "25 July 1998" |
|---|
| 18 | .SH NAME |
|---|
| 19 | ares_process \- Process events for name resolution |
|---|
| 20 | .SH SYNOPSIS |
|---|
| 21 | .nf |
|---|
| 22 | .B #include <ares.h> |
|---|
| 23 | .PP |
|---|
| 24 | .B void ares_process(ares_channel \fIchannel\fP, fd_set *\fIread_fds\fP, |
|---|
| 25 | .B fd_set *\fIwrite_fds\fP) |
|---|
| 26 | .fi |
|---|
| 27 | .SH DESCRIPTION |
|---|
| 28 | The |
|---|
| 29 | .B ares_process |
|---|
| 30 | function handles input/output events and timeouts associated with |
|---|
| 31 | queries pending on the name service channel identified by |
|---|
| 32 | .IR channel . |
|---|
| 33 | The file descriptor sets pointed to by |
|---|
| 34 | .I read_fds |
|---|
| 35 | and |
|---|
| 36 | .I write_fds |
|---|
| 37 | should have file descriptors set in them according to whether the file |
|---|
| 38 | descriptors specified by |
|---|
| 39 | .BR ares_fds (3) |
|---|
| 40 | are ready for reading and writing. (The easiest way to determine this |
|---|
| 41 | information is to invoke |
|---|
| 42 | .B select |
|---|
| 43 | with a timeout no greater than the timeout given by |
|---|
| 44 | .BR ares_timeout (3)). |
|---|
| 45 | .PP |
|---|
| 46 | The |
|---|
| 47 | .B ares_process |
|---|
| 48 | function will invoke callbacks for pending queries if they complete |
|---|
| 49 | successfully or fail. |
|---|
| 50 | .SS EXAMPLE |
|---|
| 51 | The following code fragment waits for all pending queries on a channel |
|---|
| 52 | to complete: |
|---|
| 53 | .PP |
|---|
| 54 | .RS |
|---|
| 55 | .nf |
|---|
| 56 | int nfds, count; |
|---|
| 57 | fd_set readers, writers; |
|---|
| 58 | struct timeval tv, *tvp; |
|---|
| 59 | |
|---|
| 60 | while (1) |
|---|
| 61 | { |
|---|
| 62 | FD_ZERO(&readers); |
|---|
| 63 | FD_ZERO(&writers); |
|---|
| 64 | nfds = ares_fds(channel, &readers, &writers); |
|---|
| 65 | if (nfds == 0) |
|---|
| 66 | break; |
|---|
| 67 | tvp = ares_timeout(channel, NULL, &tv); |
|---|
| 68 | count = select(nfds, &readers, &writers, NULL, tvp); |
|---|
| 69 | ares_process(channel, &readers, &writers); |
|---|
| 70 | } |
|---|
| 71 | .fi |
|---|
| 72 | .RE |
|---|
| 73 | .SH SEE ALSO |
|---|
| 74 | .BR ares_fds (3), |
|---|
| 75 | .BR ares_timeout (3) |
|---|
| 76 | .SH AUTHOR |
|---|
| 77 | Greg Hudson, MIT Information Systems |
|---|
| 78 | .br |
|---|
| 79 | Copyright 1998 by the Massachusetts Institute of Technology. |
|---|
