Line data    Source code

       1             : /* gethrxtime -- get high resolution real time
       2             : 
       3             :    Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
       4             : 
       5             :    This program is free software: you can redistribute it and/or modify
       6             :    it under the terms of the GNU General Public License as published by
       7             :    the Free Software Foundation; either version 3 of the License, or
       8             :    (at your option) any later version.
       9             : 
      10             :    This program is distributed in the hope that it will be useful,
      11             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13             :    GNU General Public License for more details.
      14             : 
      15             :    You should have received a copy of the GNU General Public License
      16             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      17             : 
      18             : /* Written by Paul Eggert.  */
      19             : 
      20             : #include <config.h>
      21             : 
      22             : #include "gethrxtime.h"
      23             : 
      24             : #include <sys/time.h>
      25             : #include "timespec.h"
      26             : 
      27             : /* Get the current time, as a count of the number of nanoseconds since
      28             :    an arbitrary epoch (e.g., the system boot time).  Prefer a
      29             :    high-resolution clock that is not subject to resetting or
      30             :    drifting.  */
      31             : 
      32             : xtime_t
      33          22 : gethrxtime (void)
      34             : {
      35             : #if HAVE_NANOUPTIME
      36             :   {
      37             :     struct timespec ts;
      38             :     nanouptime (&ts);
      39             :     return xtime_make (ts.tv_sec, ts.tv_nsec);
      40             :   }
      41             : #else
      42             : 
      43             : # if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
      44             :   {
      45             :     struct timespec ts;
      46          22 :     if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0)
      47          22 :       return xtime_make (ts.tv_sec, ts.tv_nsec);
      48             :   }
      49             : # endif
      50             : 
      51             : # if HAVE_MICROUPTIME
      52             :   {
      53             :     struct timeval tv;
      54             :     microuptime (&tv);
      55             :     return xtime_make (tv.tv_sec, 1000 * tv.tv_usec);
      56             :   }
      57             : 
      58             : # else
      59             :   /* No monotonically increasing clocks are available; fall back on a
      60             :      clock that might jump backwards, since it's the best we can do.  */
      61             :   {
      62             :     struct timespec ts;
      63           0 :     gettime (&ts);
      64           0 :     return xtime_make (ts.tv_sec, ts.tv_nsec);
      65             :   }
      66             : # endif
      67             : #endif
      68             : }