1 | /* gethrxtime -- get high resolution real time |
2 | |
3 | Copyright (C) 2005-2007, 2009-2019 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 <https://www.gnu.org/licenses/>. */ |
17 | |
18 | /* Written by Paul Eggert. */ |
19 | |
20 | #include <config.h> |
21 | |
22 | #define GETHRXTIME_INLINE _GL_EXTERN_INLINE |
23 | #include "gethrxtime.h" |
24 | |
25 | #if ! (HAVE_ARITHMETIC_HRTIME_T && HAVE_DECL_GETHRTIME) |
26 | |
27 | #include <sys/time.h> |
28 | #include "timespec.h" |
29 | |
30 | /* Get the current time, as a count of the number of nanoseconds since |
31 | an arbitrary epoch (e.g., the system boot time). Prefer a |
32 | high-resolution clock that is not subject to resetting or |
33 | drifting. */ |
34 | |
35 | xtime_t |
36 | gethrxtime (void) |
37 | { |
38 | # if HAVE_NANOUPTIME |
39 | { |
40 | struct timespec ts; |
41 | nanouptime (&ts); |
42 | return xtime_make (ts.tv_sec, ts.tv_nsec); |
43 | } |
44 | # else |
45 | |
46 | # if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME |
47 | { |
48 | struct timespec ts; |
49 | if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0) |
50 | return xtime_make (ts.tv_sec, ts.tv_nsec); |
51 | } |
52 | # endif |
53 | |
54 | # if HAVE_MICROUPTIME |
55 | { |
56 | struct timeval tv; |
57 | microuptime (&tv); |
58 | return xtime_make (tv.tv_sec, 1000 * tv.tv_usec); |
59 | } |
60 | |
61 | # else |
62 | /* No monotonically increasing clocks are available; fall back on a |
63 | clock that might jump backwards, since it's the best we can do. */ |
64 | { |
65 | struct timespec ts; |
66 | gettime (&ts); |
67 | return xtime_make (ts.tv_sec, ts.tv_nsec); |
68 | } |
69 | # endif |
70 | # endif |
71 | } |
72 | |
73 | #endif |
74 | |