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authorPaul Eggert <eggert@cs.ucla.edu>2005-02-21 08:05:49 +0000
committerPaul Eggert <eggert@cs.ucla.edu>2005-02-21 08:05:49 +0000
commit9df4b1d7e4dd38a5b0efd0614e04f18395663274 (patch)
treeb851f96560385531eaa69dc569059f45a3203ffd /lib/gethrxtime.c
parent80cc962bd565f3f502adff2b33be342be6ef4bbb (diff)
downloadcoreutils-9df4b1d7e4dd38a5b0efd0614e04f18395663274.tar.xz
Initial revision.
Diffstat (limited to 'lib/gethrxtime.c')
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diff --git a/lib/gethrxtime.c b/lib/gethrxtime.c
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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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/* Written by Paul Eggert. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "gethrxtime.h"
+
+#include <sys/types.h>
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+# include <sys/time.h>
+# else
+# include <time.h>
+# endif
+#endif
+
+/* Get the time of a high-resolution clock, preferably one 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);
+ }
+
+ /* No monotonically increasing clocks are available; fall back on a
+ clock that might jump backwards, since it's the best we can do. */
+# elif HAVE_GETTIMEOFDAY && XTIME_PRECISION != 1
+ {
+ struct timeval tv;
+ gettimeofday (&tv, NULL);
+ return xtime_make (tv.tv_sec, 1000 * tv.tv_usec);
+ }
+# else
+ return xtime_make (time (NULL), 0);
+# endif
+#endif
+}