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pgtime.h
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1 /*-------------------------------------------------------------------------
2  *
3  * pgtime.h
4  * PostgreSQL internal timezone library
5  *
6  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
7  *
8  * IDENTIFICATION
9  * src/include/pgtime.h
10  *
11  *-------------------------------------------------------------------------
12  */
13 #ifndef _PGTIME_H
14 #define _PGTIME_H
15 
16 
17 /*
18  * The API of this library is generally similar to the corresponding
19  * C library functions, except that we use pg_time_t which (we hope) is
20  * 64 bits wide, and which is most definitely signed not unsigned.
21  */
22 
23 typedef int64 pg_time_t;
24 
25 /*
26  * Data structure representing a broken-down timestamp.
27  *
28  * CAUTION: the IANA timezone library (src/timezone/) follows the POSIX
29  * convention that tm_mon counts from 0 and tm_year is relative to 1900.
30  * However, Postgres' datetime functions generally treat tm_mon as counting
31  * from 1 and tm_year as relative to 1 BC. Be sure to make the appropriate
32  * adjustments when moving from one code domain to the other.
33  */
34 struct pg_tm
35 {
36  int tm_sec;
37  int tm_min;
38  int tm_hour;
39  int tm_mday;
40  int tm_mon; /* see above */
41  int tm_year; /* see above */
42  int tm_wday;
43  int tm_yday;
44  int tm_isdst;
45  long int tm_gmtoff;
46  const char *tm_zone;
47 };
48 
49 /* These structs are opaque outside the timezone library */
50 typedef struct pg_tz pg_tz;
51 typedef struct pg_tzenum pg_tzenum;
52 
53 /* Maximum length of a timezone name (not including trailing null) */
54 #define TZ_STRLEN_MAX 255
55 
56 /* these functions are in localtime.c */
57 
58 extern struct pg_tm *pg_localtime(const pg_time_t *timep, const pg_tz *tz);
59 extern struct pg_tm *pg_gmtime(const pg_time_t *timep);
60 extern int pg_next_dst_boundary(const pg_time_t *timep,
61  long int *before_gmtoff,
62  int *before_isdst,
63  pg_time_t *boundary,
64  long int *after_gmtoff,
65  int *after_isdst,
66  const pg_tz *tz);
67 extern bool pg_interpret_timezone_abbrev(const char *abbrev,
68  const pg_time_t *timep,
69  long int *gmtoff,
70  int *isdst,
71  const pg_tz *tz);
72 extern bool pg_get_timezone_offset(const pg_tz *tz, long int *gmtoff);
73 extern const char *pg_get_timezone_name(pg_tz *tz);
74 extern bool pg_tz_acceptable(pg_tz *tz);
75 
76 /* these functions are in strftime.c */
77 
78 extern size_t pg_strftime(char *s, size_t maxsize, const char *format,
79  const struct pg_tm *t);
80 
81 /* these functions and variables are in pgtz.c */
82 
85 
86 extern void pg_timezone_initialize(void);
87 extern pg_tz *pg_tzset(const char *tzname);
88 extern pg_tz *pg_tzset_offset(long gmtoffset);
89 
90 extern pg_tzenum *pg_tzenumerate_start(void);
91 extern pg_tz *pg_tzenumerate_next(pg_tzenum *dir);
92 extern void pg_tzenumerate_end(pg_tzenum *dir);
93 
94 #endif /* _PGTIME_H */
#define PGDLLIMPORT
Definition: c.h:1252
static char format
bool pg_tz_acceptable(pg_tz *tz)
Definition: localtime.c:1890
int pg_next_dst_boundary(const pg_time_t *timep, long int *before_gmtoff, int *before_isdst, pg_time_t *boundary, long int *after_gmtoff, int *after_isdst, const pg_tz *tz)
Definition: localtime.c:1610
pg_tz * pg_tzset_offset(long gmtoffset)
Definition: pgtz.c:320
const char * pg_get_timezone_name(pg_tz *tz)
Definition: localtime.c:1875
void pg_timezone_initialize(void)
Definition: pgtz.c:361
struct pg_tm * pg_gmtime(const pg_time_t *timep)
Definition: localtime.c:1389
bool pg_get_timezone_offset(const pg_tz *tz, long int *gmtoff)
Definition: localtime.c:1851
PGDLLIMPORT pg_tz * session_timezone
Definition: pgtz.c:28
pg_tz * pg_tzset(const char *tzname)
Definition: pgtz.c:234
pg_tz * pg_tzenumerate_next(pg_tzenum *dir)
Definition: pgtz.c:426
int64 pg_time_t
Definition: pgtime.h:23
struct pg_tm * pg_localtime(const pg_time_t *timep, const pg_tz *tz)
Definition: localtime.c:1344
void pg_tzenumerate_end(pg_tzenum *dir)
Definition: pgtz.c:414
pg_tzenum * pg_tzenumerate_start(void)
Definition: pgtz.c:397
size_t pg_strftime(char *s, size_t maxsize, const char *format, const struct pg_tm *t)
Definition: strftime.c:128
PGDLLIMPORT pg_tz * log_timezone
Definition: pgtz.c:31
bool pg_interpret_timezone_abbrev(const char *abbrev, const pg_time_t *timep, long int *gmtoff, int *isdst, const pg_tz *tz)
Definition: localtime.c:1757
Definition: pgtime.h:35
int tm_hour
Definition: pgtime.h:38
int tm_mday
Definition: pgtime.h:39
int tm_mon
Definition: pgtime.h:40
int tm_min
Definition: pgtime.h:37
const char * tm_zone
Definition: pgtime.h:46
int tm_yday
Definition: pgtime.h:43
int tm_wday
Definition: pgtime.h:42
int tm_sec
Definition: pgtime.h:36
int tm_isdst
Definition: pgtime.h:44
long int tm_gmtoff
Definition: pgtime.h:45
int tm_year
Definition: pgtime.h:41
Definition: pgtz.h:66