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/* gethrxtime -- get high resolution real time
Copyright (C) 2005 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, 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, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/* Written by Paul Eggert. */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include "gethrxtime.h"
#include "timespec.h"
/* Get the current time, as a count of the number of nanoseconds since
an arbitrary epoch (e.g., the system boot time). Prefer a
high-resolution clock that is not subject to resetting or
drifting. */
xtime_t
gethrxtime (void)
{
#if HAVE_NANOUPTIME
{
struct timespec ts;
nanouptime (&ts);
return xtime_make (ts.tv_sec, ts.tv_nsec);
}
#else
# if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
{
struct timespec ts;
if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0)
return xtime_make (ts.tv_sec, ts.tv_nsec);
}
# endif
# if HAVE_MICROUPTIME
{
struct timeval tv;
microuptime (&tv);
return xtime_make (tv.tv_sec, 1000 * tv.tv_usec);
}
# else
/* No monotonically increasing clocks are available; fall back on a
clock that might jump backwards, since it's the best we can do. */
{
struct timespec ts;
gettime (&ts);
return xtime_make (ts.tv_sec, ts.tv_nsec);
}
# endif
#endif
}
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