diff options
Diffstat (limited to 'lib/gethrxtime.c')
-rw-r--r-- | lib/gethrxtime.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/lib/gethrxtime.c b/lib/gethrxtime.c new file mode 100644 index 0000000..2046e06 --- /dev/null +++ b/lib/gethrxtime.c @@ -0,0 +1,69 @@ +/* gethrxtime -- get high resolution real time + + Copyright (C) 2005, 2006, 2007 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. */ + +#include <config.h> + +#include "gethrxtime.h" + +#include <sys/time.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 +} |