update from main archive 960927
[glibc.git] / time / time.h
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1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
17 Cambridge, MA 02139, USA. */
20 * ANSI Standard: 4.12 DATE and TIME <time.h>
23 #ifndef _TIME_H
25 #if (! defined (__need_time_t) && !defined (__need_clock_t) && \
26 ! defined (__need_timespec))
27 #define _TIME_H 1
28 #include <features.h>
30 __BEGIN_DECLS
32 #endif
34 #ifdef _TIME_H
35 /* Get size_t and NULL from <stddef.h>. */
36 #define __need_size_t
37 #define __need_NULL
38 #include <stddef.h>
39 #endif /* <time.h> included. */
43 #ifdef _TIME_H
45 /* This defines CLOCKS_PER_SEC, which is the number of processor clock
46 ticks per second. */
47 #include <timebits.h>
49 /* This is the obsolete POSIX.1-1988 name for the same constant. */
50 #ifdef __USE_POSIX
51 #define CLK_TCK CLOCKS_PER_SEC
52 #endif
54 #endif /* <time.h> included. */
57 #if !defined (__clock_t_defined) && \
58 (defined (_TIME_H) || defined (__need_clock_t))
59 #define __clock_t_defined 1
61 #include <gnu/types.h>
63 /* Returned by `clock'. */
64 typedef __clock_t clock_t;
66 #endif /* clock_t not defined and <time.h> or need clock_t. */
67 #undef __need_clock_t
69 #if !defined (__time_t_defined) && \
70 (defined (_TIME_H) || defined (__need_time_t))
71 #define __time_t_defined 1
73 #include <gnu/types.h>
75 /* Returned by `time'. */
76 typedef __time_t time_t;
78 #endif /* time_t not defined and <time.h> or need time_t. */
79 #undef __need_time_t
82 #if ! defined (__timespec_defined) && \
83 ((defined (_TIME_H) && defined (__USE_POSIX)) || \
84 defined (__need_timespec))
85 #define __timespec_defined 1
87 /* POSIX.4 structure for a time value. This is like a `struct timeval' but
88 has nanoseconds instead of microseconds. */
89 struct timespec
91 long int tv_sec; /* Seconds. */
92 long int tv_nsec; /* Nanoseconds. */
95 #endif /* timespec not defined and <time.h> or need timespec. */
96 #undef __need_timespec
100 #ifdef _TIME_H
101 /* Used by other time functions. */
102 struct tm
104 int tm_sec; /* Seconds. [0-60] (1 leap second) */
105 int tm_min; /* Minutes. [0-59] */
106 int tm_hour; /* Hours. [0-23] */
107 int tm_mday; /* Day. [1-31] */
108 int tm_mon; /* Month. [0-11] */
109 int tm_year; /* Year - 1900. */
110 int tm_wday; /* Day of week. [0-6] */
111 int tm_yday; /* Days in year.[0-365] */
112 int tm_isdst; /* DST. [-1/0/1]*/
114 #ifdef __USE_BSD
115 long int tm_gmtoff; /* Seconds east of UTC. */
116 __const char *tm_zone; /* Timezone abbreviation. */
117 #else
118 long int __tm_gmtoff; /* Seconds east of UTC. */
119 __const char *__tm_zone; /* Timezone abbreviation. */
120 #endif
123 #endif /* <time.h> included. */
126 #ifdef _TIME_H
127 /* Time used by the program so far (user time + system time).
128 The result / CLOCKS_PER_SECOND is program time in seconds. */
129 extern clock_t clock __P ((void));
131 /* Return the current time and put it in *TIMER if TIMER is not NULL. */
132 extern time_t time __P ((time_t *__timer));
134 /* Return the difference between TIME1 and TIME0. */
135 extern double difftime __P ((time_t __time1, time_t __time0))
136 __attribute__ ((__const__));
138 /* Return the `time_t' representation of TP and normalize TP. */
139 extern time_t mktime __P ((struct tm *__tp));
141 /* Subroutine of `mktime'. Return the `time_t' representation of TP and
142 normalize TP, given that a `struct tm *' maps to a `time_t' as performed
143 by FUNC. Keep track of next guess for time_t offset in *OFFSET. */
144 extern time_t __mktime_internal __P ((struct tm *__tp,
145 struct tm *(*__func) (const time_t *,
146 struct tm *),
147 time_t *__offset));
150 /* Format TP into S according to FORMAT.
151 Write no more than MAXSIZE characters and return the number
152 of characters written, or 0 if it would exceed MAXSIZE. */
153 extern size_t strftime __P ((char *__s, size_t __maxsize,
154 __const char *__format, __const struct tm *__tp));
156 #ifdef __USE_MISC
157 /* Parse S according to FORMAT and store binary time information in TP.
158 The return value is a pointer to the first unparsed character in S. */
159 extern char *strptime __P ((__const char *__s, __const char *__fmt,
160 struct tm *__tp));
161 #endif
164 /* Return the `struct tm' representation of *TIMER
165 in Universal Coordinated Time (aka Greenwich Mean Time). */
166 extern struct tm *gmtime __P ((__const time_t *__timer));
168 /* Return the `struct tm' representation
169 of *TIMER in the local timezone. */
170 extern struct tm *localtime __P ((__const time_t *__timer));
172 #ifdef __USE_REENTRANT
173 /* Return the `struct tm' representation of *TIMER in UTC,
174 using *TP to store the result. */
175 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
176 struct tm *__tp));
177 extern struct tm *gmtime_r __P ((__const time_t *__timer,
178 struct tm *__tp));
180 /* Return the `struct tm' representation of *TIMER in local time,
181 using *TP to store the result. */
182 extern struct tm *__localtime_r __P ((__const time_t *__timer,
183 struct tm *__tp));
184 extern struct tm *localtime_r __P ((__const time_t *__timer,
185 struct tm *__tp));
186 #endif /* reentrant */
188 /* Compute the `struct tm' representation of *T,
189 offset OFFSET seconds east of UTC,
190 and store year, yday, mon, mday, wday, hour, min, sec into *TP. */
191 extern void __offtime __P ((__const time_t *__timer,
192 long int __offset,
193 struct tm *__TP));
195 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
196 that is the representation of TP in this format. */
197 extern char *asctime __P ((__const struct tm *__tp));
199 /* Equivalent to `asctime (localtime (timer))'. */
200 extern char *ctime __P ((__const time_t *__timer));
202 #ifdef __USE_REENTRANT
203 /* Reentrant versions of the above functions. */
205 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
206 that is the representation of TP in this format. */
207 extern char *__asctime_r __P ((__const struct tm *__tp, char *__buf));
208 extern char *asctime_r __P ((__const struct tm *__tp, char *__buf));
210 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'. */
211 extern char *ctime_r __P ((__const time_t *__timer, char *__buf));
212 #endif /* reentrant */
215 /* Defined in localtime.c. */
216 extern char *__tzname[2]; /* Current timezone names. */
217 extern int __daylight; /* If daylight-saving time is ever in use. */
218 extern long int __timezone; /* Seconds west of UTC. */
220 /* Set time conversion information from the TZ environment variable.
221 If TZ is not defined, a locale-dependent default is used. */
222 extern void __tzset __P ((void));
224 #ifdef __USE_POSIX
225 /* Same as above. */
226 extern char *tzname[2];
228 /* Return the maximum length of a timezone name.
229 This is what `sysconf (_SC_TZNAME_MAX)' does. */
230 extern long int __tzname_max __P ((void));
232 extern void tzset __P ((void));
233 #endif
235 #ifdef __USE_SVID
236 extern int daylight;
237 extern long int timezone;
239 /* Set the system time to *WHEN.
240 This call is restricted to the superuser. */
241 extern int stime __P ((__const time_t *__when));
242 #endif
245 /* Nonzero if YEAR is a leap year (every 4 years,
246 except every 100th isn't, and every 400th is). */
247 #define __isleap(year) \
248 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
251 #ifdef __USE_MISC
252 /* Miscellaneous functions many Unices inherited from the public domain
253 localtime package. These are included only for compatibility. */
255 /* Like `mktime', but for TP represents Universal Time, not local time. */
256 extern time_t timegm __P ((struct tm *__tp));
258 /* Another name for `mktime'. */
259 extern time_t timelocal __P ((struct tm *__tp));
261 /* Return the number of days in YEAR. */
262 extern int dysize __P ((int __year));
263 #endif
266 #ifdef __USE_POSIX
267 /* Pause execution for a number of nanoseconds. */
268 extern int __nanosleep __P ((__const struct timespec *__requested_time,
269 struct timespec *__remaining));
270 extern int nanosleep __P ((__const struct timespec *__requested_time,
271 struct timespec *__remaining));
272 #endif
275 __END_DECLS
277 #endif /* <time.h> included. */
279 #endif /* <time.h> not already included. */