curl/ares/ares_process.3

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.\" $Id$
.\"
.\" Copyright 1998 by the Massachusetts Institute of Technology.
.\"
.\" Permission to use, copy, modify, and distribute this
.\" software and its documentation for any purpose and without
.\" fee is hereby granted, provided that the above copyright
.\" notice appear in all copies and that both that copyright
.\" notice and this permission notice appear in supporting
.\" documentation, and that the name of M.I.T. not be used in
.\" advertising or publicity pertaining to distribution of the
.\" software without specific, written prior permission.
.\" M.I.T. makes no representations about the suitability of
.\" this software for any purpose. It is provided "as is"
.\" without express or implied warranty.
.\"
.TH ARES_PROCESS 3 "25 July 1998"
.SH NAME
ares_process \- Process events for name resolution
.SH SYNOPSIS
.nf
.B #include <ares.h>
.PP
.B void ares_process(ares_channel \fIchannel\fP, fd_set *\fIread_fds\fP,
.B fd_set *\fIwrite_fds\fP)
.fi
.SH DESCRIPTION
The
.B ares_process
function handles input/output events and timeouts associated with
queries pending on the name service channel identified by
.IR channel .
The file descriptor sets pointed to by
.I read_fds
and
.I write_fds
should have file descriptors set in them according to whether the file
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descriptors specified by \fIares_fds(3)\fP are ready for reading and writing.
(The easiest way to determine this information is to invoke
.B select
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with a timeout no greater than the timeout given by \fIares_timeout(3)\fP ).
.PP
The
.B ares_process
function will invoke callbacks for pending queries if they complete
successfully or fail.
.SS EXAMPLE
The following code fragment waits for all pending queries on a channel
to complete:
.PP
.RS
.nf
int nfds, count;
fd_set readers, writers;
struct timeval tv, *tvp;
while (1)
{
FD_ZERO(&readers);
FD_ZERO(&writers);
nfds = ares_fds(channel, &readers, &writers);
if (nfds == 0)
break;
tvp = ares_timeout(channel, NULL, &tv);
count = select(nfds, &readers, &writers, NULL, tvp);
ares_process(channel, &readers, &writers);
}
.fi
.RE
.SH SEE ALSO
.BR ares_fds (3),
.BR ares_timeout (3)
.SH AUTHOR
Greg Hudson, MIT Information Systems
.br
Copyright 1998 by the Massachusetts Institute of Technology.