GRASS GIS 8 Programmer's Manual 8.3.2(2024)-exported
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sign.c
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1/*
2 * Copyright (C) 1995. Bill Brown <brown@gis.uiuc.edu> & Michael Shapiro
3 *
4 * This program is free software under the GPL (>=v2)
5 * Read the file GPL.TXT coming with GRASS for details.
6 */
7#include <grass/datetime.h>
8
9/*!
10 * \brief
11 *
12 * Returns:
13 * 1 if the Datetime is positive
14 * 0 otherwise
15 *
16 * \param dt
17 * \return int
18 */
19
20int datetime_is_positive(const DateTime *dt)
21{
22 return dt->positive != 0;
23}
24
25/*!
26 * \brief
27 *
28 * Returns:
29 * 1 if the DateTime is negative
30 * 0 otherwise
31 *
32 * \param dt
33 * \return int
34 */
35
36int datetime_is_negative(const DateTime *dt)
37{
38 return dt->positive == 0;
39}
40
41/*!
42 * \brief
43 *
44 * Makes the DateTime positive. (A.D. for ABSOLUTE DateTimes)
45 *
46 * \param dt
47 * \return void
48 */
49
50void datetime_set_positive(DateTime *dt)
51{
52 dt->positive = 1;
53}
54
55/*!
56 * \brief
57 *
58 * Makes the DateTime negative. (B.C. for ABSOLUTE DateTimes)
59 *
60 * \param dt
61 * \return void
62 */
63
64void datetime_set_negative(DateTime *dt)
65{
66 dt->positive = 0;
67}
68
69/*!
70 * \brief
71 *
72 * \param dt
73 * \return void
74 */
75
76void datetime_invert_sign(DateTime *dt)
77{
78 dt->positive = !dt->positive;
79}
int datetime_is_negative(const DateTime *dt)
Returns: 1 if the DateTime is negative 0 otherwise.
Definition sign.c:36
int datetime_is_positive(const DateTime *dt)
Returns: 1 if the Datetime is positive 0 otherwise.
Definition sign.c:20
void datetime_set_negative(DateTime *dt)
Makes the DateTime negative. (B.C. for ABSOLUTE DateTimes)
Definition sign.c:64
void datetime_set_positive(DateTime *dt)
Makes the DateTime positive. (A.D. for ABSOLUTE DateTimes)
Definition sign.c:50
void datetime_invert_sign(DateTime *dt)
Definition sign.c:76