Added ares_getsock() to extract sockets to wait for action on, without being

limited to select().

1 files changed, 56 insertions, 0 deletions

diff --git a/ares_getsock.3 b/ares_getsock.3
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+.\" $Id$
+.\"
+.\" Copyright 1998 by Daniel Stenberg
+.\"
+.\" 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_GETSOCK 3 "22 December 2005"
+.SH NAME
+ares_getsock \- get file descriptors to wait on
+.SH SYNOPSIS
+.nf
+.B #include <ares.h>
+.PP
+.B int ares_getsock(ares_channel \fIchannel\fP, int *\fIsocks\fP, 
+.B int \fInumsocks\fP);
+.fi
+.SH DESCRIPTION
+The
+.B ares_getsock
+function retrieves the set of file descriptors which the calling
+application should wait on for reading and/or writing for the
+processing of name service queries pending on the name service channel
+identified by
+.IR channel .
+File descriptors will be set in the integer array pointed to by
+\fIsocks\fP.
+\fInumsocks\fP is the size of the given array in number of ints.
+
+This function can only return information about up to 16 sockets. If more are
+in use (however unlikely that is), they are simply not reported back.
+.SH RETURN VALUES
+\fBares_getsock\fP returns a bitmask for what actions to wait for on the
+different sockets. The ares.h header file provides these convenience macros to
+extract the information appropriately:
+
+.nf
+#define ARES_GETSOCK_MAXNUM 16 /* ares_getsock() can return info about
+                                  this many sockets */
+#define ARES_GETSOCK_READABLE(bits,num) (bits & (1<< (num)))
+#define ARES_GETSOCK_WRITABLE(bits,num) (bits & (1 << ((num) + \
+                                         ARES_GETSOCK_MAXNUM)))
+.fi
+.SH SEE ALSO
+.BR ares_timeout (3),
+.BR ares_fds (3),
+.BR ares_process (3)