/* Pausing execution of the current thread.

   Copyright (C) 2009-2019 Free Software Foundation, Inc.

   Written by Eric Blake <ebb9@byu.net>, 2009.

   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 3 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, see <https://www.gnu.org/licenses/>.  */

/* This file is _intentionally_ light-weight.  Rather than using

   select or nanosleep, both of which drag in external libraries on

   some platforms, this merely rounds up to the nearest second if

   usleep() does not exist.  If sub-second resolution is important,

   then use a more powerful interface to begin with.  */

#include <config.h>

/* Specification.  */

#include <unistd.h>

#include <errno.h>

#ifndef HAVE_USLEEP

# define HAVE_USLEEP 0

#endif

/* Sleep for MICRO microseconds, which can be greater than 1 second.

   Return -1 and set errno to EINVAL on range error (about 4295

   seconds), or 0 on success.  Interaction with SIGALARM is

   unspecified.  */

int

usleep (useconds_t micro)

{

  unsigned int seconds = micro / 1000000;

  if (sizeof seconds < sizeof micro && micro / 1000000 != seconds)

    {

      errno = EINVAL;

      return -1;

    }

  if (!HAVE_USLEEP && micro % 1000000)

    seconds++;

  while ((seconds = sleep (seconds)) != 0);

#undef usleep

#if !HAVE_USLEEP

# define usleep(x) 0

#endif

  return usleep (micro % 1000000);

}