| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | .\" |
| 2 | .\" Copyright 1998 by the Massachusetts Institute of Technology. |
| 3 | .\" |
| 4 | .\" Permission to use, copy, modify, and distribute this |
| 5 | .\" software and its documentation for any purpose and without |
| 6 | .\" fee is hereby granted, provided that the above copyright |
| 7 | .\" notice appear in all copies and that both that copyright |
| 8 | .\" notice and this permission notice appear in supporting |
| 9 | .\" documentation, and that the name of M.I.T. not be used in |
| 10 | .\" advertising or publicity pertaining to distribution of the |
| 11 | .\" software without specific, written prior permission. |
| 12 | .\" M.I.T. makes no representations about the suitability of |
| 13 | .\" this software for any purpose. It is provided "as is" |
| 14 | .\" without express or implied warranty. |
| 15 | .\" |
| 16 | .TH ARES_PROCESS 3 "25 July 1998" |
| 17 | .SH NAME |
| 18 | ares_process \- Process events for name resolution |
| 19 | .SH SYNOPSIS |
| 20 | .nf |
| 21 | .B #include <ares.h> |
| 22 | .PP |
| 23 | .B void ares_process(ares_channel \fIchannel\fP, fd_set *\fIread_fds\fP, |
| 24 | .B fd_set *\fIwrite_fds\fP) |
| 25 | .fi |
| 26 | .PP |
| 27 | .B void ares_process_fd(ares_channel \fIchannel\fP, |
| 28 | .B ares_socket_t \fIread_fd\fP, |
| 29 | .B ares_socket_t \fIwrite_fd\fP) |
| 30 | .fi |
| 31 | .SH DESCRIPTION |
| 32 | The \fBares_process(3)\fP function handles input/output events and timeouts |
| 33 | associated with queries pending on the name service channel identified by |
| 34 | .IR channel . |
| 35 | The file descriptor sets pointed to by \fIread_fds\fP and \fIwrite_fds\fP |
| 36 | should have file descriptors set in them according to whether the file |
| 37 | descriptors specified by \fIares_fds(3)\fP are ready for reading and writing. |
| 38 | (The easiest way to determine this information is to invoke |
| 39 | .B select |
| 40 | with a timeout no greater than the timeout given by \fIares_timeout(3)\fP ). |
| 41 | .PP |
| 42 | The |
| 43 | .B ares_process |
| 44 | function will invoke callbacks for pending queries if they complete |
| 45 | successfully or fail. |
| 46 | |
| 47 | \fBares_process_fd(3)\fP works the same way but acts and operates only on the |
| 48 | specific file descriptors (sockets) you pass in to the function. Use |
| 49 | ARES_SOCKET_BAD for "no action". This function is of course provided to allow |
| 50 | users of c-ares to void select() in their applications and within c-ares. |
| 51 | .SS EXAMPLE |
| 52 | The following code fragment waits for all pending queries on a channel |
| 53 | to complete: |
| 54 | .PP |
| 55 | .RS |
| 56 | .nf |
| 57 | int nfds, count; |
| 58 | fd_set readers, writers; |
| 59 | struct timeval tv, *tvp; |
| 60 | |
| 61 | while (1) |
| 62 | { |
| 63 | FD_ZERO(&readers); |
| 64 | FD_ZERO(&writers); |
| 65 | nfds = ares_fds(channel, &readers, &writers); |
| 66 | if (nfds == 0) |
| 67 | break; |
| 68 | tvp = ares_timeout(channel, NULL, &tv); |
| 69 | count = select(nfds, &readers, &writers, NULL, tvp); |
| 70 | ares_process(channel, &readers, &writers); |
| 71 | } |
| 72 | .fi |
| 73 | .RE |
| 74 | .SH SEE ALSO |
| 75 | .BR ares_fds (3), |
| 76 | .BR ares_timeout (3) |
| 77 | .SH AUTHOR |
| 78 | Greg Hudson, MIT Information Systems |
| 79 | .br |
| 80 | Copyright 1998 by the Massachusetts Institute of Technology. |