1 .TH CTIME 3
2 .SH NAME
3 ctime, localtime, gmtime, asctime, tm2sec, timezone \- convert date and time
4 .SH SYNOPSIS
5 .B #include <u.h>
6 .br
7 .B #include <libc.h>
8 .PP
9 .ta \w'\fLchar* 'u
10 .B
11 char*	ctime(long clock)
12 .PP
13 .B
14 Tm*	localtime(long clock)
15 .PP
16 .B
17 Tm*	gmtime(long clock)
18 .PP
19 .B
20 char*	asctime(Tm *tm)
21 .PP
22 .B
23 long	tm2sec(Tm *tm)
24 .SH DESCRIPTION
25 .I Ctime
26 converts a time
27 .I clock
28 such as returned by
29 .IR time (3)
30 into
31 .SM ASCII
32 (sic)
33 and returns a pointer to a
34 30-byte string
35 in the following form.
36 All the fields have constant width.
37 .PP
38 .B
39 	Wed Aug  5 01:07:47 EST 1973\en\e0
40 .PP
41 .I Localtime
42 and
43 .I gmtime
44 return pointers to structures containing
45 the broken-down time.
46 .I Localtime
47 corrects for the time zone and possible daylight savings time;
48 .I gmtime
49 converts directly to GMT.
50 .I Asctime
51 converts a broken-down time to
52 .SM ASCII
53 and returns a pointer
54 to a 30-byte string.
55 .IP
56 .EX
57 .ta 6n +\w'char 'u +\w'zone[4];    'u
58 typedef
59 struct {
60 	int	sec;	/* seconds (range 0..59) */
61 	int	min;	/* minutes (0..59) */
62 	int	hour;	/* hours (0..23) */
63 	int	mday;	/* day of the month (1..31) */
64 	int	mon;	/* month of the year (0..11) */
65 	int	year;	/* year A.D. \- 1900 */
66 	int	wday;	/* day of week (0..6, Sunday = 0) */
67 	int	yday;	/* day of year (0..365) */
68 	char	zone[4];	/* time zone name */
69 	int	tzoff;	/* time zone delta from GMT */
70 } Tm;
71 .EE
72 .PP
73 .I Tm2sec
74 converts a broken-down time to
75 seconds since the start of the epoch.
76 It ignores
77 .BR wday ,
78 and assumes the local time zone
79 if
80 .B zone
81 is not
82 .BR GMT .
83 .SH SOURCE
84 .B \*9/src/lib9/date.c
85 .br
86 .B \*9/src/lib9/ctime.c
87 .SH "SEE ALSO"
88 .IR date (1),
89 .IR time (3)
90 .SH BUGS
91 The return values point to static data
92 whose content is overwritten by each call.
93 .PP
94 Daylight Savings Time is ``normal'' in the Southern hemisphere.
95 .PP
96 These routines are not equipped to handle non-\c
97 .SM ASCII
98 text, and are provincial anyway.
99 .PP
100 To avoid name conflicts with the underlying system,
101 .IR ctime ,
102 .IR localtime ,
103 .IR gmtime ,
104 .IR asctime ,
105 and
106 .I tm2sec
107 are preprocessor macros defined as
108 .IR p9ctime ,
109 .IR p9localtime ,
110 .IR p9gmtime ,
111 .IR p9asctime ,
112 and
113 .IR p9tm2sec ;
114 see
115 .IR intro (3).