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3rdparty/c-ares-1.18.1/docs/ares_get_servers.3 3.22 KB
73ef4ff3   Hu Chunming   提交三方库
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  .\"
  .\" Copyright 1998 by the Massachusetts Institute of Technology.
  .\" Copyright (C) 2008-2010 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_GET_SERVERS 3 "5 March 2010"
  .SH NAME
  ares_get_servers, ares_get_servers_ports \- Retrieve name servers from an initialized ares_channel
  .SH SYNOPSIS
  .nf
  .B #include <ares.h>
  .PP
  .B int ares_get_servers(ares_channel \fIchannel\fP, struct ares_addr_node **\fIservers\fP)
  .B int ares_get_servers_ports(ares_channel \fIchannel\fP, struct ares_addr_port_node **\fIservers\fP)
  .fi
  .SH DESCRIPTION
  The \fBares_get_servers(3)\fP function retrieves name servers configuration
  from the
  channel data identified by
  .IR channel ,
  as a linked list of ares_addr_node structs storing a pointer to the first
  node at the address specified by
  .IR servers .
  
  The \fBares_get_servers_ports(3)\fP function also retrieves any per-server
  port information that may have been previously configured, returning a linked
  list of ares_addr_port structures.
  
  Function caller may traverse the returned name server linked list, or may use
  it directly as suitable input for the \fBares_set_servers(3)\fP /
  \fBares_set_servers_ports(3)\fP functions, but
  shall not shrink or extend the list on its own.
  
  Each node of the name server linked list is stored in memory dynamically
  allocated and managed by c-ares. It is the caller's responsibility to free
  the resulting linked list, using \fBares_free_data(3)\fP , once the caller
  does not need it any longer.
  
  This function is capable of handling IPv4 and IPv6 name server
  addresses simultaneously, rendering \fBares_save_options(3)\fP with
  optmask \fBARES_OPT_SERVERS\fP functionally obsolete except for
  IPv4-only name server usage.
  
  .SH RETURN VALUES
  This function may return any of the following values:
  .TP 15
  .B ARES_SUCCESS
  The name servers configuration was successfully retrieved
  .TP 15
  .B ARES_ENOMEM
  The memory was exhausted
  .TP 15
  .B ARES_ENODATA
  The channel data identified by
  .IR channel
  was invalid.
  .SH SEE ALSO
  .BR ares_set_servers (3),
  .BR ares_init_options (3),
  .BR ares_save_options(3)
  .SH AVAILABILITY
  \fBares_get_servers(3)\fP was added in c-ares 1.7.1;
  \fBares_get_servers_ports(3)\fP was added in c-ares 1.11.0.
  .SH AUTHOR
  Implementation of this function and associated library internals are based
  on code, comments and feedback provided in November and December of 2008 by
  Daniel Stenberg, Gregor Jasny, Phil Blundell and Yang Tse, December 2009
  by Cedric Bail, February 2010 by Jakub Hrozek. On March 2010 Yang Tse
  shuffled all the bits and this function popped out.
  .br
  Copyright 1998 by the Massachusetts Institute of Technology.
  .br
  Copyright (C) 2008-2010 by Daniel Stenberg