A C library for asynchronous DNS requests (grpc依赖)
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.\"
.\" Copyright 1998 by the Massachusetts Institute of Technology.
.\" Copyright (C) 2008-2010 by Daniel Stenberg
.\" SPDX-License-Identifier: MIT
.\"
.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 (deprecated)
.SH SYNOPSIS
.nf
#include <ares.h>
int ares_get_servers(ares_channel_t *\fIchannel\fP,
struct ares_addr_node **\fIservers\fP)
int ares_get_servers_ports(ares_channel_t *\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 NOTES
As of c-ares 1.24, these functions are deprecated due to their lack of ability
to store the entire server configuration. Use \fBares_get_servers_csv(3)\fP.