/* Sleep for a given number of seconds.  POSIX.1 version.

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

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

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

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <time.h>

#include <unistd.h>

#include <errno.h>

#include <sys/param.h>

/* Make the process sleep for SECONDS seconds, or until a signal arrives

   and is not ignored.  The function returns the number of seconds less

   than SECONDS which it actually slept (zero if it slept the full time).

   If a signal handler does a `longjmp' or modifies the handling of the

   SIGALRM signal while inside `sleep' call, the handling of the SIGALRM

   signal afterwards is undefined.  There is no return value to indicate

   error, but if `sleep' returns SECONDS, it probably didn't work.  */

unsigned int

__sleep (unsigned int seconds)

{

  int save_errno = errno;

  const unsigned int max

    = (unsigned int) (((unsigned long int) (~((time_t) 0))) >> 1);

  struct timespec ts = { 0, 0 };

  do

    {

      if (sizeof (ts.tv_sec) <= sizeof (seconds))

        {

          /* Since SECONDS is unsigned assigning the value to .tv_sec can

             overflow it.  In this case we have to wait in steps.  */

          ts.tv_sec += MIN (seconds, max);

          seconds -= (unsigned int) ts.tv_sec;

        }

      else

        {

          ts.tv_sec = (time_t) seconds;

          seconds = 0;

        }

      if (__nanosleep (&ts, &ts) < 0)

        /* We were interrupted.

           Return the number of (whole) seconds we have not yet slept.  */

        return seconds + ts.tv_sec;

    }

  while (seconds > 0);

  __set_errno (save_errno);

  return 0;

}

weak_alias (__sleep, sleep)