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1/* Copyright (C) 1991-2025 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
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 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18/*
19 * ISO C99 Standard: 7.23 Date and time <time.h>
20 */
21
22#ifndef _TIME_H
23#define _TIME_H 1
24
25#include <features.h>
26
27#define __need_size_t
28#define __need_NULL
29#include <stddef.h>
30
31/* This defines CLOCKS_PER_SEC, which is the number of processor clock
32 ticks per second, and possibly a number of other constants. */
33#include <bits/time.h>
34
35/* Many of the typedefs and structs whose official home is this header
36 may also need to be defined by other headers. */
37#include <bits/types/clock_t.h>
38#include <bits/types/time_t.h>
39#include <bits/types/struct_tm.h>
40
41#if defined __USE_POSIX199309 || defined __USE_ISOC11
42# include <bits/types/struct_timespec.h>
43#endif
44
45#ifdef __USE_POSIX199309
46# include <bits/types/clockid_t.h>
47# include <bits/types/timer_t.h>
48# include <bits/types/struct_itimerspec.h>
49struct sigevent;
50#endif
51
52#ifdef __USE_XOPEN2K
53# ifndef __pid_t_defined
54typedef __pid_t pid_t;
55# define __pid_t_defined
56# endif
57#endif
58
59#ifdef __USE_XOPEN2K8
60# include <bits/types/locale_t.h>
61#endif
62
63#ifdef __USE_ISOC11
64/* Time base values for timespec_get. */
65# define TIME_UTC 1
66#endif
67
68__BEGIN_DECLS
69
70/* Time used by the program so far (user time + system time).
71 The result / CLOCKS_PER_SEC is program time in seconds. */
72extern clock_t clock (void) __THROW;
73
74#ifndef __USE_TIME64_REDIRECTS
75/* Return the current time and put it in *TIMER if TIMER is not NULL. */
76extern time_t time (time_t *__timer) __THROW;
77
78/* Return the difference between TIME1 and TIME0. */
79extern double difftime (time_t __time1, time_t __time0);
80
81/* Return the `time_t' representation of TP and normalize TP. */
82extern time_t mktime (struct tm *__tp) __THROW;
83#else
84# ifdef __REDIRECT_NTH
85extern time_t __REDIRECT_NTH (time, (time_t *__timer), __time64);
86extern double __REDIRECT_NTH (difftime, (time_t __time1, time_t __time0),
87 __difftime64);
88extern time_t __REDIRECT_NTH (mktime, (struct tm *__tp), __mktime64);
89# else
90# define time __time64
91# define difftime __difftime64
92# define mktime __mktime64
93# endif
94#endif
95
96/* Format TP into S according to FORMAT.
97 Write no more than MAXSIZE characters and return the number
98 of characters written, or 0 if it would exceed MAXSIZE. */
99extern size_t strftime (char *__restrict __s, size_t __maxsize,
100 const char *__restrict __format,
101 const struct tm *__restrict __tp)
102 __THROW __nonnull((1, 3, 4));
103
104#ifdef __USE_XOPEN
105/* Parse S according to FORMAT and store binary time information in TP.
106 The return value is a pointer to the first unparsed character in S. */
107extern char *strptime (const char *__restrict __s,
108 const char *__restrict __fmt, struct tm *__tp)
109 __THROW;
110#endif
111
112#ifdef __USE_XOPEN2K8
113/* Similar to the two functions above but take the information from
114 the provided locale and not the global locale. */
115
116extern size_t strftime_l (char *__restrict __s, size_t __maxsize,
117 const char *__restrict __format,
118 const struct tm *__restrict __tp,
119 locale_t __loc) __THROW;
120#endif
121
122#ifdef __USE_GNU
123extern char *strptime_l (const char *__restrict __s,
124 const char *__restrict __fmt, struct tm *__tp,
125 locale_t __loc) __THROW;
126#endif
127
128
129#ifndef __USE_TIME64_REDIRECTS
130/* Return the `struct tm' representation of *TIMER
131 in Universal Coordinated Time (aka Greenwich Mean Time). */
132extern struct tm *gmtime (const time_t *__timer) __THROW;
133
134/* Return the `struct tm' representation
135 of *TIMER in the local timezone. */
136extern struct tm *localtime (const time_t *__timer) __THROW;
137
138#else
139# ifdef __REDIRECT_NTH
140extern struct tm*__REDIRECT_NTH (gmtime, (const time_t *__timer), __gmtime64);
141extern struct tm *__REDIRECT_NTH (localtime, (const time_t *__timer),
142 __localtime64);
143# else
144# define gmtime __gmtime64
145# define localtime __localtime64
146# endif
147#endif
148
149
150#if defined __USE_POSIX || __GLIBC_USE (ISOC23)
151# ifndef __USE_TIME64_REDIRECTS
152/* Return the `struct tm' representation of *TIMER in UTC,
153 using *TP to store the result. */
154extern struct tm *gmtime_r (const time_t *__restrict __timer,
155 struct tm *__restrict __tp) __THROW;
156
157/* Return the `struct tm' representation of *TIMER in local time,
158 using *TP to store the result. */
159extern struct tm *localtime_r (const time_t *__restrict __timer,
160 struct tm *__restrict __tp) __THROW;
161# else
162# ifdef __REDIRECT_NTH
163extern struct tm*__REDIRECT_NTH (gmtime_r, (const time_t *__restrict __timer,
164 struct tm *__restrict __tp),
165 __gmtime64_r);
166
167extern struct tm*__REDIRECT_NTH (localtime_r, (const time_t *__restrict __t,
168 struct tm *__restrict __tp),
169 __localtime64_r);
170# else
171# define gmtime_r __gmtime64_r
172# define localtime_r __localtime_r
173# endif
174# endif
175#endif /* POSIX || C23 */
176
177/* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
178 that is the representation of TP in this format. */
179extern char *asctime (const struct tm *__tp) __THROW;
180
181/* Equivalent to `asctime (localtime (timer))'. */
182#ifndef __USE_TIME64_REDIRECTS
183extern char *ctime (const time_t *__timer) __THROW;
184#else
185# ifdef __REDIRECT_NTH
186extern char *__REDIRECT_NTH (ctime, (const time_t *__timer), __ctime64);
187# else
188# define ctime __ctime64
189# endif
190#endif
191
192#ifdef __USE_POSIX
193/* Reentrant versions of the above functions. */
194
195/* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
196 that is the representation of TP in this format. */
197extern char *asctime_r (const struct tm *__restrict __tp,
198 char *__restrict __buf) __THROW;
199
200/* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'. */
201#ifndef __USE_TIME64_REDIRECTS
202extern char *ctime_r (const time_t *__restrict __timer,
203 char *__restrict __buf) __THROW;
204#else
205# ifdef __REDIRECT_NTH
206extern char *__REDIRECT_NTH (ctime_r, (const time_t *__restrict __timer,
207 char *__restrict __buf), __ctime64_r);
208# else
209# define ctime_r __ctime64_r
210# endif
211#endif
212
213#endif /* POSIX */
214
215
216/* Defined in localtime.c. */
217extern char *__tzname[2]; /* Current time zone abbreviations. */
218extern int __daylight; /* If daylight-saving time is ever in use. */
219extern long int __timezone; /* Seconds west of UTC. */
220
221
222#ifdef __USE_POSIX
223/* Same as above. */
224extern char *tzname[2];
225
226/* Set time conversion information from the TZ environment variable.
227 If TZ is not defined, a locale-dependent default is used. */
228extern void tzset (void) __THROW;
229#endif
230
231#if defined __USE_MISC || defined __USE_XOPEN
232extern int daylight;
233extern long int timezone;
234#endif
235
236
237/* Nonzero if YEAR is a leap year (every 4 years,
238 except every 100th isn't, and every 400th is). */
239#define __isleap(year) \
240 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
241
242
243#if defined __USE_MISC || __GLIBC_USE (ISOC23)
244# ifndef __USE_TIME64_REDIRECTS
245/* Like `mktime', but for TP represents Universal Time, not local time. */
246extern time_t timegm (struct tm *__tp) __THROW;
247# else
248# ifdef __REDIRECT_NTH
249extern time_t __REDIRECT_NTH (timegm, (struct tm *__tp), __timegm64);
250# else
251# define timegm __timegm64
252# endif
253# endif
254#endif
255
256
257#ifdef __USE_MISC
258/* Miscellaneous functions many Unices inherited from the public domain
259 localtime package. These are included only for compatibility. */
260
261#ifndef __USE_TIME64_REDIRECTS
262/* Another name for `mktime'. */
263extern time_t timelocal (struct tm *__tp) __THROW;
264#else
265# ifdef __REDIRECT_NTH
266extern time_t __REDIRECT_NTH (timelocal, (struct tm *__tp), __mktime64);
267# endif
268#endif
269
270/* Return the number of days in YEAR. */
271extern int dysize (int __year) __THROW __attribute__ ((__const__));
272#endif
273
274
275#ifdef __USE_POSIX199309
276# ifndef __USE_TIME64_REDIRECTS
277/* Pause execution for a number of nanoseconds.
278
279 This function is a cancellation point and therefore not marked with
280 __THROW. */
281extern int nanosleep (const struct timespec *__requested_time,
282 struct timespec *__remaining);
283
284/* Get resolution of clock CLOCK_ID. */
285extern int clock_getres (clockid_t __clock_id, struct timespec *__res) __THROW;
286
287/* Get current value of clock CLOCK_ID and store it in TP. */
288extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp)
289 __THROW __nonnull((2));
290
291/* Set clock CLOCK_ID to value TP. */
292extern int clock_settime (clockid_t __clock_id, const struct timespec *__tp)
293 __THROW __nonnull((2));
294# else
295# ifdef __REDIRECT
296extern int __REDIRECT (nanosleep, (const struct timespec *__requested_time,
297 struct timespec *__remaining),
298 __nanosleep64);
299extern int __REDIRECT_NTH (clock_getres, (clockid_t __clock_id,
300 struct timespec *__res),
301 __clock_getres64);
302extern int __REDIRECT_NTH (clock_gettime, (clockid_t __clock_id, struct
303 timespec *__tp), __clock_gettime64)
304 __nonnull((2));
305extern int __REDIRECT_NTH (clock_settime, (clockid_t __clock_id, const struct
306 timespec *__tp), __clock_settime64)
307 __nonnull((2));
308# else
309# define nanosleep __nanosleep64
310# define clock_getres __clock_getres64
311# define clock_gettime __clock_gettime64
312# define clock_settime __clock_settime64
313# endif
314# endif
315
316
317# ifdef __USE_XOPEN2K
318/* High-resolution sleep with the specified clock.
319
320 This function is a cancellation point and therefore not marked with
321 __THROW. */
322# ifndef __USE_TIME64_REDIRECTS
323extern int clock_nanosleep (clockid_t __clock_id, int __flags,
324 const struct timespec *__req,
325 struct timespec *__rem);
326# else
327# ifdef __REDIRECT
328extern int __REDIRECT (clock_nanosleep, (clockid_t __clock_id, int __flags,
329 const struct timespec *__req,
330 struct timespec *__rem),
331 __clock_nanosleep_time64);
332# else
333# define clock_nanosleep __clock_nanosleep_time64
334# endif
335# endif
336
337/* Return clock ID for CPU-time clock. */
338extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __THROW;
339# endif
340
341
342/* Create new per-process timer using CLOCK_ID. */
343extern int timer_create (clockid_t __clock_id,
344 struct sigevent *__restrict __evp,
345 timer_t *__restrict __timerid) __THROW;
346
347/* Delete timer TIMERID. */
348extern int timer_delete (timer_t __timerid) __THROW;
349
350/* Set timer TIMERID to VALUE, returning old value in OVALUE. */
351# ifndef __USE_TIME64_REDIRECTS
352extern int timer_settime (timer_t __timerid, int __flags,
353 const struct itimerspec *__restrict __value,
354 struct itimerspec *__restrict __ovalue) __THROW;
355
356/* Get current value of timer TIMERID and store it in VALUE. */
357extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
358 __THROW;
359# else
360# ifdef __REDIRECT_NTH
361extern int __REDIRECT_NTH (timer_settime, (timer_t __timerid, int __flags,
362 const struct itimerspec *__restrict __value,
363 struct itimerspec *__restrict __ovalue),
364 __timer_settime64);
365
366extern int __REDIRECT_NTH (timer_gettime, (timer_t __timerid,
367 struct itimerspec *__value),
368 __timer_gettime64);
369# else
370# define timer_settime __timer_settime64
371# define timer_gettime __timer_gettime64
372# endif
373# endif
374
375/* Get expiration overrun for timer TIMERID. */
376extern int timer_getoverrun (timer_t __timerid) __THROW;
377#endif
378
379
380#ifdef __USE_ISOC11
381# ifndef __USE_TIME64_REDIRECTS
382/* Set TS to calendar time based in time base BASE. */
383extern int timespec_get (struct timespec *__ts, int __base)
384 __THROW __nonnull ((1));
385# else
386# ifdef __REDIRECT_NTH
387extern int __REDIRECT_NTH (timespec_get, (struct timespec *__ts, int __base),
388 __timespec_get64) __nonnull ((1));
389# else
390# define timespec_get __timespec_get64
391# endif
392# endif
393#endif
394
395
396#if __GLIBC_USE (ISOC23)
397# ifndef __USE_TIME64_REDIRECTS
398/* Set TS to resolution of time base BASE. */
399extern int timespec_getres (struct timespec *__ts, int __base)
400 __THROW;
401# else
402# ifdef __REDIRECT_NTH
403extern int __REDIRECT_NTH (timespec_getres, (struct timespec *__ts,
404 int __base),
405 __timespec_getres64);
406# else
407# define timespec_getres __timespec_getres64
408# endif
409# endif
410#endif
411
412
413#ifdef __USE_XOPEN_EXTENDED
414/* Set to one of the following values to indicate an error.
415 1 the DATEMSK environment variable is null or undefined,
416 2 the template file cannot be opened for reading,
417 3 failed to get file status information,
418 4 the template file is not a regular file,
419 5 an error is encountered while reading the template file,
420 6 memory allication failed (not enough memory available),
421 7 there is no line in the template that matches the input,
422 8 invalid input specification Example: February 31 or a time is
423 specified that can not be represented in a time_t (representing
424 the time in seconds since 00:00:00 UTC, January 1, 1970) */
425extern int getdate_err;
426
427/* Parse the given string as a date specification and return a value
428 representing the value. The templates from the file identified by
429 the environment variable DATEMSK are used. In case of an error
430 `getdate_err' is set.
431
432 This function is a possible cancellation point and therefore not
433 marked with __THROW. */
434extern struct tm *getdate (const char *__string);
435#endif
436
437#ifdef __USE_GNU
438/* Since `getdate' is not reentrant because of the use of `getdate_err'
439 and the static buffer to return the result in, we provide a thread-safe
440 variant. The functionality is the same. The result is returned in
441 the buffer pointed to by RESBUFP and in case of an error the return
442 value is != 0 with the same values as given above for `getdate_err'.
443
444 This function is not part of POSIX and therefore no official
445 cancellation point. But due to similarity with an POSIX interface
446 or due to the implementation it is a cancellation point and
447 therefore not marked with __THROW. */
448extern int getdate_r (const char *__restrict __string,
449 struct tm *__restrict __resbufp);
450#endif
451
452__END_DECLS
453
454#endif /* time.h. */