time/time.h

   1 /* Copyright (C) 1991-2024 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>
  49 struct sigevent;
  50 #endif
  51
  52 #ifdef __USE_XOPEN2K
  53 # ifndef __pid_t_defined
  54 typedef __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.  */
  72 extern 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.  */
  76 extern time_t time (time_t *__timer) __THROW;
  77
  78 /* Return the difference between TIME1 and TIME0.  */
  79 extern double difftime (time_t __time1, time_t __time0);
  80
  81 /* Return the `time_t' representation of TP and normalize TP.  */
  82 extern time_t mktime (struct tm *__tp) __THROW;
  83 #else
  84 # ifdef __REDIRECT_NTH
  85 extern time_t __REDIRECT_NTH (time, (time_t *__timer), __time64);
  86 extern double __REDIRECT_NTH (difftime, (time_t __time1, time_t __time0),
  87                               __difftime64);
  88 extern 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.  */
  99 extern 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.  */
 107 extern 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
 116 extern 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
 123 extern 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).  */
 132 extern struct tm *gmtime (const time_t *__timer) __THROW;
 133
 134 /* Return the `struct tm' representation
 135    of *TIMER in the local timezone.  */
 136 extern struct tm *localtime (const time_t *__timer) __THROW;
 137
 138 #else
 139 # ifdef __REDIRECT_NTH
 140 extern struct tm*__REDIRECT_NTH (gmtime, (const time_t *__timer), __gmtime64);
 141 extern 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.  */
 154 extern 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.  */
 159 extern struct tm *localtime_r (const time_t *__restrict __timer,
 160                                struct tm *__restrict __tp) __THROW;
 161 # else
 162 #  ifdef __REDIRECT_NTH
 163 extern struct tm*__REDIRECT_NTH (gmtime_r, (const time_t *__restrict __timer,
 164                                             struct tm *__restrict __tp),
 165                                  __gmtime64_r);
 166
 167 extern 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.  */
 179 extern char *asctime (const struct tm *__tp) __THROW;
 180
 181 /* Equivalent to `asctime (localtime (timer))'.  */
 182 #ifndef __USE_TIME64_REDIRECTS
 183 extern char *ctime (const time_t *__timer) __THROW;
 184 #else
 185 # ifdef __REDIRECT_NTH
 186 extern 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.  */
 197 extern 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
 202 extern char *ctime_r (const time_t *__restrict __timer,
 203                       char *__restrict __buf) __THROW;
 204 #else
 205 # ifdef __REDIRECT_NTH
 206 extern 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.  */
 217 extern char *__tzname[2];       /* Current time zone abbreviations.  */
 218 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 219 extern long int __timezone;     /* Seconds west of UTC.  */
 220
 221
 222 #ifdef  __USE_POSIX
 223 /* Same as above.  */
 224 extern 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.  */
 228 extern void tzset (void) __THROW;
 229 #endif
 230
 231 #if defined __USE_MISC || defined __USE_XOPEN
 232 extern int daylight;
 233 extern 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.  */
 246 extern time_t timegm (struct tm *__tp) __THROW;
 247 # else
 248 #  ifdef __REDIRECT_NTH
 249 extern 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'.  */
 263 extern time_t timelocal (struct tm *__tp) __THROW;
 264 #else
 265 # ifdef __REDIRECT_NTH
 266 extern time_t __REDIRECT_NTH (timelocal, (struct tm *__tp), __mktime64);
 267 # endif
 268 #endif
 269
 270 /* Return the number of days in YEAR.  */
 271 extern 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.  */
 281 extern int nanosleep (const struct timespec *__requested_time,
 282                       struct timespec *__remaining);
 283
 284 /* Get resolution of clock CLOCK_ID.  */
 285 extern 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.  */
 288 extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp)
 289      __THROW __nonnull((2));
 290
 291 /* Set clock CLOCK_ID to value TP.  */
 292 extern int clock_settime (clockid_t __clock_id, const struct timespec *__tp)
 293      __THROW __nonnull((2));
 294 # else
 295 #  ifdef __REDIRECT
 296 extern int __REDIRECT (nanosleep, (const struct timespec *__requested_time,
 297                                    struct timespec *__remaining),
 298                        __nanosleep64);
 299 extern int __REDIRECT_NTH (clock_getres, (clockid_t __clock_id,
 300                                           struct timespec *__res),
 301                            __clock_getres64);
 302 extern int __REDIRECT_NTH (clock_gettime, (clockid_t __clock_id, struct
 303                                            timespec *__tp), __clock_gettime64)
 304                            __nonnull((2));
 305 extern 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
 323 extern int clock_nanosleep (clockid_t __clock_id, int __flags,
 324                             const struct timespec *__req,
 325                             struct timespec *__rem);
 326 #  else
 327 #   ifdef __REDIRECT
 328 extern 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.  */
 338 extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __THROW;
 339 # endif
 340
 341
 342 /* Create new per-process timer using CLOCK_ID.  */
 343 extern int timer_create (clockid_t __clock_id,
 344                          struct sigevent *__restrict __evp,
 345                          timer_t *__restrict __timerid) __THROW;
 346
 347 /* Delete timer TIMERID.  */
 348 extern int timer_delete (timer_t __timerid) __THROW;
 349
 350 /* Set timer TIMERID to VALUE, returning old value in OVALUE.  */
 351 # ifndef __USE_TIME64_REDIRECTS
 352 extern 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.  */
 357 extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
 358      __THROW;
 359 # else
 360 #  ifdef __REDIRECT_NTH
 361 extern 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
 366 extern 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.  */
 376 extern 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.  */
 383 extern int timespec_get (struct timespec *__ts, int __base)
 384      __THROW __nonnull ((1));
 385 # else
 386 #  ifdef __REDIRECT_NTH
 387 extern 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.  */
 399 extern int timespec_getres (struct timespec *__ts, int __base)
 400      __THROW;
 401 # else
 402 #  ifdef __REDIRECT_NTH
 403 extern 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) */
 425 extern 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.  */
 434 extern 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.  */
 448 extern int getdate_r (const char *__restrict __string,
 449                       struct tm *__restrict __resbufp);
 450 #endif
 451
 452 __END_DECLS
 453
 454 #endif /* time.h.  */