/* Waiting for Input or Output

   Copyright (C) 1991-2018 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or

   modify it under the terms of the GNU General Public License

   as published by the Free Software Foundation; either version 2

   of the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; if not, if not, see <http://www.gnu.org/licenses/>.

*/

/*@group*/

#include <errno.h>

#include <stdio.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/time.h>

/*@end group*/

/*@group*/

int

input_timeout (int filedes, unsigned int seconds)

{

  fd_set set;

  struct timeval timeout;

/*@end group*/

  /* Initialize the file descriptor set. */

  FD_ZERO (&set);

  FD_SET (filedes, &set);

  /* Initialize the timeout data structure. */

  timeout.tv_sec = seconds;

  timeout.tv_usec = 0;

/*@group*/

  /* @code{select} returns 0 if timeout, 1 if input available, -1 if error. */

  return TEMP_FAILURE_RETRY (select (FD_SETSIZE,

				     &set, NULL, NULL,

				     &timeout));

}

/*@end group*/

/*@group*/

int

main (void)

{

  fprintf (stderr, "select returned %d.\n",

	   input_timeout (STDIN_FILENO, 5));

  return 0;

}

/*@end group*/