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/* Copyright 1998 by the Massachusetts Institute of Technology.
*
* 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.
*/
#include "ares_setup.h"
#include "ares.h"
#include "ares_nowarn.h"
#include "ares_private.h"
int ares_fds(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
{
struct server_state *server;
ares_socket_t nfds;
int i;
/* Are there any active queries? */
int active_queries = !ares__is_list_empty(&(channel->all_queries));
nfds = 0;
for (i = 0; i < channel->nservers; i++)
{
server = &channel->servers[i];
/* We only need to register interest in UDP sockets if we have
* outstanding queries.
*/
if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
{
FD_SET(server->udp_socket, read_fds);
if (server->udp_socket >= nfds)
nfds = server->udp_socket + 1;
}
/* We always register for TCP events, because we want to know
* when the other side closes the connection, so we don't waste
* time trying to use a broken connection.
*/
if (server->tcp_socket != ARES_SOCKET_BAD)
{
FD_SET(server->tcp_socket, read_fds);
if (server->qhead)
FD_SET(server->tcp_socket, write_fds);
if (server->tcp_socket >= nfds)
nfds = server->tcp_socket + 1;
}
}
return (int)nfds;
}
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