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82 lines
2.5 KiB
C
82 lines
2.5 KiB
C
/* High-resolution sleep with the specified clock.
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Copyright (C) 2000 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <assert.h>
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#include <errno.h>
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#include <sys/time.h>
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#ifndef CLOCK_P
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# define CLOCK_P(clock) 0
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#endif
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/* This implementation assumes that these is only a `nanosleep' system
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call. So we have to remap all other activities. */
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int
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clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
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struct timespec *rem)
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{
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struct timespec now;
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if (__builtin_expect (req->tv_nsec, 0) < 0
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|| __builtin_expect (req->tv_nsec, 0) >= 1000000000)
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return EINVAL;
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/* If we got an absolute time, remap it. */
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if (flags == TIMER_ABSTIME)
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{
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long int nsec;
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long int sec;
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/* Make sure we use safe data types. */
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assert (sizeof (sec) >= sizeof (now.tv_sec));
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/* Get the current time for this clock. */
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if (__builtin_expect (clock_gettime (clock_id, &now), 0) != 0)
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return errno;
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/* Compute the difference. */
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nsec = req->tv_nsec - now.tv_nsec;
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sec = req->tv_sec - now.tv_sec - (nsec < 0);
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if (sec < 0)
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/* The time has already elapsed. */
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return 0;
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now.tv_sec = sec;
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now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
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/* From now on this is our time. */
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req = &now;
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/* Make sure we are not modifying the struct pointed to by REM. */
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rem = NULL;
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}
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else if (__builtin_expect (flags, 0) != 0)
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return EINVAL;
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else if (clock_id != CLOCK_REALTIME)
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{
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/* Make sure the clock ID is correct. */
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if (__builtin_expect (! CLOCK_P (clock_id), 0))
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return EINVAL;
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}
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return __builtin_expect (nanosleep (req, rem), 0) ? errno : 0;
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}
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