1 /* timespec -- System time interface
2
3 Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2021 Free Software
4 Foundation, Inc.
5
6 This file is free software: you can redistribute it and/or modify
7 it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 3 of the
9 License, or (at your option) any later version.
10
11 This file is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with this program. If not, see <https://www.gnu.org/licenses/>. */
18
19 #if ! defined TIMESPEC_H
20 #define TIMESPEC_H
21
22 #include <time.h>
23
24 #ifndef _GL_INLINE_HEADER_BEGIN
25 #error "Please include config.h first."
26 #endif
27 _GL_INLINE_HEADER_BEGIN
28 #ifndef _GL_TIMESPEC_INLINE
29 # define _GL_TIMESPEC_INLINE _GL_INLINE
30 #endif
31
32 #ifdef __cplusplus
33 extern "C" {
34 #endif
35
36 #include "arg-nonnull.h"
37
38 /* Inverse resolution of timespec timestamps (in units per second),
39 and log base 10 of the inverse resolution. */
40
41 enum { TIMESPEC_HZ = 1000000000 };
42 enum { LOG10_TIMESPEC_HZ = 9 };
43
44 /* Obsolescent names for backward compatibility.
45 They are misnomers, because TIMESPEC_RESOLUTION is not a resolution. */
46
47 enum { TIMESPEC_RESOLUTION = TIMESPEC_HZ };
48 enum { LOG10_TIMESPEC_RESOLUTION = LOG10_TIMESPEC_HZ };
49
50 /* Return a timespec with seconds S and nanoseconds NS. */
51
52 _GL_TIMESPEC_INLINE struct timespec
make_timespec(time_t s,long int ns)53 make_timespec (time_t s, long int ns)
54 {
55 struct timespec r;
56 r.tv_sec = s;
57 r.tv_nsec = ns;
58 return r;
59 }
60
61 /* Return negative, zero, positive if A < B, A == B, A > B, respectively. */
62
63 _GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
timespec_cmp(struct timespec a,struct timespec b)64 timespec_cmp (struct timespec a, struct timespec b)
65 {
66 return 2 * _GL_CMP (a.tv_sec, b.tv_sec) + _GL_CMP (a.tv_nsec, b.tv_nsec);
67 }
68
69 /* Return -1, 0, 1, depending on the sign of A. A.tv_nsec must be
70 nonnegative. */
71 _GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
timespec_sign(struct timespec a)72 timespec_sign (struct timespec a)
73 {
74 return _GL_CMP (a.tv_sec, 0) + (!a.tv_sec & !!a.tv_nsec);
75 }
76
77 struct timespec timespec_add (struct timespec, struct timespec)
78 _GL_ATTRIBUTE_CONST;
79 struct timespec timespec_sub (struct timespec, struct timespec)
80 _GL_ATTRIBUTE_CONST;
81 struct timespec dtotimespec (double)
82 _GL_ATTRIBUTE_CONST;
83
84 /* Return an approximation to A, of type 'double'. */
85 _GL_TIMESPEC_INLINE double
timespectod(struct timespec a)86 timespectod (struct timespec a)
87 {
88 return a.tv_sec + a.tv_nsec / 1e9;
89 }
90
91 struct timespec current_timespec (void);
92 void gettime (struct timespec *) _GL_ARG_NONNULL ((1));
93 int settime (struct timespec const *) _GL_ARG_NONNULL ((1));
94
95 #ifdef __cplusplus
96 }
97 #endif
98
99 _GL_INLINE_HEADER_END
100
101 #endif
102