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