NAME¶
ares_set_servers, ares_set_servers_ports - Initialize an ares_channel name
servers configuration
SYNOPSIS¶
#include <ares.h>
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)
DESCRIPTION¶
The
ares_set_servers(3) function initializes name servers configuration
for the channel data identified by
channel, from a
servers
pointer to a linked list of ares_addr_node structs holding name servers
address data.
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 single
list.
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.
RETURN VALUES¶
ares_set_servers(3) may return any of the following values:
- ARES_SUCCESS
- The name servers configuration was successfully initialized.
- ARES_ENOMEM
- The process's available memory was exhausted.
- ARES_ENODATA
- The channel data identified by channel was invalid.
- ARES_ENOTINITIALIZED
- c-ares library initialization not yet performed.
SEE ALSO¶
ares_set_servers_csv(3),
ares_get_servers(3),
ares_init_options(3),
ares_dup(3)
AVAILABILITY¶
ares_set_servers(3) was added in c-ares 1.7.1;
ares_set_servers_ports(3) was added in c-ares 1.11.0.
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.
Copyright 1998 by the Massachusetts Institute of Technology.
Copyright (C) 2008-2010 by Daniel Stenberg