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3rdparty/c-ares-1.18.1/release/share/man/man3/ares_getsock.3 2.11 KB
73ef4ff3   Hu Chunming   提交三方库
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  .\"
  .\" 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 "11 March 2010"
  .SH NAME
  ares_getsock \- get socket descriptors to wait on
  .SH SYNOPSIS
  .nf
  .B #include <ares.h>
  .PP
  .B int ares_getsock(ares_channel \fIchannel\fP, ares_socket_t *\fIsocks\fP,
  .B int \fInumsocks\fP);
  .fi
  .SH DESCRIPTION
  The
  .B ares_getsock
  function retrieves the set of socket 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 .
  Socket descriptors will be set in the socket descriptor 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 NOTES
  This function was added in c-ares 1.3.1
  .SH SEE ALSO
  .BR ares_timeout (3),
  .BR ares_fds (3),
  .BR ares_process (3)