Section: C Library Functions (3)
Updated: 5 March 2010
ares_set_servers, ares_set_servers_ports - Initialize an ares_channel name servers configuration
int ares_set_servers(ares_channel channel, struct ares_addr_node *servers)
int ares_set_servers_ports(ares_channel channel, struct ares_addr_port_node *servers)
function initializes name servers configuration
for the channel data identified by
pointer to a linked list of ares_addr_node structs holding name servers
The name server linked list pointer argument may be the result of a previous
call to ares_get_servers(3) or a linked list of ares_addr_node structs
set up by other means.
The ares_set_servers(3) function also allows the specification of UDP and
TCP ports to be used for communication on a per-server basis. The provided
linked list argument may be the result of a previous call to
ares_get_servers_ports(3) or a linked list of ares_addr_port_node structs
set up by other means.
This function replaces any potentially previously configured name servers
with the ones given in the linked list. So, in order to configure a channel
with more than one name server all the desired ones must be specified in a
The function does not take ownership of the linked list argument.
The caller is responsible for freeing the linked list when no longer needed.
This function is capable of handling IPv4 and IPv6 name server
addresses simultaneously, rendering ares_init_options(3) with
optmask ARES_OPT_SERVERS functionally obsolete except for
IPv4-only name server usage.
may return any of the following values:
The name servers configuration was successfully initialized.
The process's available memory was exhausted.
The channel data identified by
c-ares library initialization not yet performed.
Changing name servers configuration while queries are outstanding is not implemented.
was added in c-ares 1.7.1;
was added in c-ares 1.11.0.
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.
Copyright 1998 by the Massachusetts Institute of Technology.
Copyright (C) 2008-2010 by Daniel Stenberg