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/* High-resolution sleep with the specified clock.
Copyright (C) 2000, 2001 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <assert.h>
#include <errno.h>
#include <time.h>
#ifndef CLOCK_P
# define CLOCK_P(clock) 0
#endif
/* This implementation assumes that these is only a `nanosleep' system
call. So we have to remap all other activities. */
int
clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
struct timespec *rem)
{
struct timespec now;
if (__builtin_expect (req->tv_nsec, 0) < 0
|| __builtin_expect (req->tv_nsec, 0) >= 1000000000)
return EINVAL;
/* If we got an absolute time, remap it. */
if (flags == TIMER_ABSTIME)
{
long int nsec;
long int sec;
/* Make sure we use safe data types. */
assert (sizeof (sec) >= sizeof (now.tv_sec));
/* Get the current time for this clock. */
if (__builtin_expect (clock_gettime (clock_id, &now), 0) != 0)
return errno;
/* Compute the difference. */
nsec = req->tv_nsec - now.tv_nsec;
sec = req->tv_sec - now.tv_sec - (nsec < 0);
if (sec < 0)
/* The time has already elapsed. */
return 0;
now.tv_sec = sec;
now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
/* From now on this is our time. */
req = &now;
/* Make sure we are not modifying the struct pointed to by REM. */
rem = NULL;
}
else if (__builtin_expect (flags, 0) != 0)
return EINVAL;
else if (clock_id != CLOCK_REALTIME)
{
/* Make sure the clock ID is correct. */
if (__builtin_expect (! CLOCK_P (clock_id), 0))
return EINVAL;
}
return __builtin_expect (nanosleep (req, rem), 0) ? errno : 0;
}
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