1 .TH CTIME 3
2 .SH NAME
3 ctime, localtime, gmtime, asctime, tm2sec \- 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 .MR 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/ctime.c
85 .br
86 .B \*9/src/lib9/tm2sec.c
87 .SH "SEE ALSO"
88 .MR date (1) ,
89 .MR 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 .MR intro (3) .