time/time.h

   1 /* Copyright (C) 1991-2023 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_TIME_BITS64
  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      __THROW __attribute__ ((__const__));
  81
  82 /* Return the `time_t' representation of TP and normalize TP.  */
  83 extern time_t mktime (struct tm *__tp) __THROW;
  84 #else
  85 # ifdef __REDIRECT_NTH
  86 extern time_t __REDIRECT_NTH (time, (time_t *__timer), __time64);
  87 extern double __REDIRECT_NTH (difftime, (time_t __time1, time_t __time0),
  88                               __difftime64) __attribute__ ((__const__));
  89 extern time_t __REDIRECT_NTH (mktime, (struct tm *__tp), __mktime64);
  90 # else
  91 #  define time __time64
  92 #  define difftime __difftime64
  93 #  define mktime __mktime64
  94 # endif
  95 #endif
  96
  97 /* Format TP into S according to FORMAT.
  98    Write no more than MAXSIZE characters and return the number
  99    of characters written, or 0 if it would exceed MAXSIZE.  */
 100 extern size_t strftime (char *__restrict __s, size_t __maxsize,
 101                         const char *__restrict __format,
 102                         const struct tm *__restrict __tp)
 103                         __THROW __nonnull((1, 3, 4));
 104
 105 #ifdef __USE_XOPEN
 106 /* Parse S according to FORMAT and store binary time information in TP.
 107    The return value is a pointer to the first unparsed character in S.  */
 108 extern char *strptime (const char *__restrict __s,
 109                        const char *__restrict __fmt, struct tm *__tp)
 110      __THROW;
 111 #endif
 112
 113 #ifdef __USE_XOPEN2K8
 114 /* Similar to the two functions above but take the information from
 115    the provided locale and not the global locale.  */
 116
 117 extern size_t strftime_l (char *__restrict __s, size_t __maxsize,
 118                           const char *__restrict __format,
 119                           const struct tm *__restrict __tp,
 120                           locale_t __loc) __THROW;
 121 #endif
 122
 123 #ifdef __USE_GNU
 124 extern char *strptime_l (const char *__restrict __s,
 125                          const char *__restrict __fmt, struct tm *__tp,
 126                          locale_t __loc) __THROW;
 127 #endif
 128
 129
 130 #ifndef __USE_TIME_BITS64
 131 /* Return the `struct tm' representation of *TIMER
 132    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 133 extern struct tm *gmtime (const time_t *__timer) __THROW;
 134
 135 /* Return the `struct tm' representation
 136    of *TIMER in the local timezone.  */
 137 extern struct tm *localtime (const time_t *__timer) __THROW;
 138
 139 #else
 140 # ifdef __REDIRECT_NTH
 141 extern struct tm*__REDIRECT_NTH (gmtime, (const time_t *__timer), __gmtime64);
 142 extern struct tm *__REDIRECT_NTH (localtime, (const time_t *__timer),
 143                                   __localtime64);
 144 # else
 145 #  define gmtime __gmtime64
 146 #  define localtime __localtime64
 147 # endif
 148 #endif
 149
 150
 151 #if defined __USE_POSIX || __GLIBC_USE (ISOC2X)
 152 # ifndef __USE_TIME_BITS64
 153 /* Return the `struct tm' representation of *TIMER in UTC,
 154    using *TP to store the result.  */
 155 extern struct tm *gmtime_r (const time_t *__restrict __timer,
 156                             struct tm *__restrict __tp) __THROW;
 157
 158 /* Return the `struct tm' representation of *TIMER in local time,
 159    using *TP to store the result.  */
 160 extern struct tm *localtime_r (const time_t *__restrict __timer,
 161                                struct tm *__restrict __tp) __THROW;
 162 # else
 163 #  ifdef __REDIRECT_NTH
 164 extern struct tm*__REDIRECT_NTH (gmtime_r, (const time_t *__restrict __timer,
 165                                             struct tm *__restrict __tp),
 166                                  __gmtime64_r);
 167
 168 extern struct tm*__REDIRECT_NTH (localtime_r, (const time_t *__restrict __t,
 169                                                struct tm *__restrict __tp),
 170                                  __localtime64_r);
 171 #  else
 172 #   define gmtime_r __gmtime64_r
 173 #   define localtime_r __localtime_r
 174 #  endif
 175 # endif
 176 #endif  /* POSIX || C2X */
 177
 178 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 179    that is the representation of TP in this format.  */
 180 extern char *asctime (const struct tm *__tp) __THROW;
 181
 182 /* Equivalent to `asctime (localtime (timer))'.  */
 183 #ifndef __USE_TIME_BITS64
 184 extern char *ctime (const time_t *__timer) __THROW;
 185 #else
 186 # ifdef __REDIRECT_NTH
 187 extern char *__REDIRECT_NTH (ctime, (const time_t *__timer), __ctime64);
 188 # else
 189 #  define ctime __ctime64
 190 # endif
 191 #endif
 192
 193 #ifdef __USE_POSIX
 194 /* Reentrant versions of the above functions.  */
 195
 196 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 197    that is the representation of TP in this format.  */
 198 extern char *asctime_r (const struct tm *__restrict __tp,
 199                         char *__restrict __buf) __THROW;
 200
 201 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 202 #ifndef __USE_TIME_BITS64
 203 extern char *ctime_r (const time_t *__restrict __timer,
 204                       char *__restrict __buf) __THROW;
 205 #else
 206 # ifdef __REDIRECT_NTH
 207 extern char *__REDIRECT_NTH (ctime_r, (const time_t *__restrict __timer,
 208                                        char *__restrict __buf), __ctime64_r);
 209 # else
 210 #  define ctime_r __ctime64_r
 211 # endif
 212 #endif
 213
 214 #endif  /* POSIX */
 215
 216
 217 /* Defined in localtime.c.  */
 218 extern char *__tzname[2];       /* Current timezone names.  */
 219 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 220 extern long int __timezone;     /* Seconds west of UTC.  */
 221
 222
 223 #ifdef  __USE_POSIX
 224 /* Same as above.  */
 225 extern char *tzname[2];
 226
 227 /* Set time conversion information from the TZ environment variable.
 228    If TZ is not defined, a locale-dependent default is used.  */
 229 extern void tzset (void) __THROW;
 230 #endif
 231
 232 #if defined __USE_MISC || defined __USE_XOPEN
 233 extern int daylight;
 234 extern long int timezone;
 235 #endif
 236
 237
 238 /* Nonzero if YEAR is a leap year (every 4 years,
 239    except every 100th isn't, and every 400th is).  */
 240 #define __isleap(year)  \
 241   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 242
 243
 244 #if defined __USE_MISC || __GLIBC_USE (ISOC2X)
 245 # ifndef __USE_TIME_BITS64
 246 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 247 extern time_t timegm (struct tm *__tp) __THROW;
 248 # else
 249 #  ifdef __REDIRECT_NTH
 250 extern time_t __REDIRECT_NTH (timegm, (struct tm *__tp), __timegm64);
 251 #  else
 252 #   define timegm __timegm64
 253 #  endif
 254 # endif
 255 #endif
 256
 257
 258 #ifdef __USE_MISC
 259 /* Miscellaneous functions many Unices inherited from the public domain
 260    localtime package.  These are included only for compatibility.  */
 261
 262 #ifndef __USE_TIME_BITS64
 263 /* Another name for `mktime'.  */
 264 extern time_t timelocal (struct tm *__tp) __THROW;
 265 #else
 266 # ifdef __REDIRECT_NTH
 267 extern time_t __REDIRECT_NTH (timelocal, (struct tm *__tp), __mktime64);
 268 # endif
 269 #endif
 270
 271 /* Return the number of days in YEAR.  */
 272 extern int dysize (int __year) __THROW  __attribute__ ((__const__));
 273 #endif
 274
 275
 276 #ifdef __USE_POSIX199309
 277 # ifndef __USE_TIME_BITS64
 278 /* Pause execution for a number of nanoseconds.
 279
 280    This function is a cancellation point and therefore not marked with
 281    __THROW.  */
 282 extern int nanosleep (const struct timespec *__requested_time,
 283                       struct timespec *__remaining);
 284
 285 /* Get resolution of clock CLOCK_ID.  */
 286 extern int clock_getres (clockid_t __clock_id, struct timespec *__res) __THROW;
 287
 288 /* Get current value of clock CLOCK_ID and store it in TP.  */
 289 extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp)
 290      __THROW __nonnull((2));
 291
 292 /* Set clock CLOCK_ID to value TP.  */
 293 extern int clock_settime (clockid_t __clock_id, const struct timespec *__tp)
 294      __THROW __nonnull((2));
 295 # else
 296 #  ifdef __REDIRECT
 297 extern int __REDIRECT (nanosleep, (const struct timespec *__requested_time,
 298                                    struct timespec *__remaining),
 299                        __nanosleep64);
 300 extern int __REDIRECT_NTH (clock_getres, (clockid_t __clock_id,
 301                                           struct timespec *__res),
 302                            __clock_getres64);
 303 extern int __REDIRECT_NTH (clock_gettime, (clockid_t __clock_id, struct
 304                                            timespec *__tp), __clock_gettime64)
 305                            __nonnull((2));
 306 extern int __REDIRECT_NTH (clock_settime, (clockid_t __clock_id, const struct
 307                                            timespec *__tp), __clock_settime64)
 308                            __nonnull((2));
 309 #  else
 310 #   define nanosleep __nanosleep64
 311 #   define clock_getres __clock_getres64
 312 #   define clock_gettime __clock_gettime64
 313 #   define clock_settime __clock_settime64
 314 #  endif
 315 # endif
 316
 317
 318 # ifdef __USE_XOPEN2K
 319 /* High-resolution sleep with the specified clock.
 320
 321    This function is a cancellation point and therefore not marked with
 322    __THROW.  */
 323 #  ifndef __USE_TIME_BITS64
 324 extern int clock_nanosleep (clockid_t __clock_id, int __flags,
 325                             const struct timespec *__req,
 326                             struct timespec *__rem);
 327 #  else
 328 #   ifdef __REDIRECT
 329 extern int __REDIRECT (clock_nanosleep, (clockid_t __clock_id, int __flags,
 330                                          const struct timespec *__req,
 331                                          struct timespec *__rem),
 332                        __clock_nanosleep_time64);
 333 #   else
 334 #    define clock_nanosleep __clock_nanosleep_time64
 335 #   endif
 336 #  endif
 337
 338 /* Return clock ID for CPU-time clock.  */
 339 extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __THROW;
 340 # endif
 341
 342
 343 /* Create new per-process timer using CLOCK_ID.  */
 344 extern int timer_create (clockid_t __clock_id,
 345                          struct sigevent *__restrict __evp,
 346                          timer_t *__restrict __timerid) __THROW;
 347
 348 /* Delete timer TIMERID.  */
 349 extern int timer_delete (timer_t __timerid) __THROW;
 350
 351 /* Set timer TIMERID to VALUE, returning old value in OVALUE.  */
 352 # ifndef __USE_TIME_BITS64
 353 extern int timer_settime (timer_t __timerid, int __flags,
 354                           const struct itimerspec *__restrict __value,
 355                           struct itimerspec *__restrict __ovalue) __THROW;
 356
 357 /* Get current value of timer TIMERID and store it in VALUE.  */
 358 extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
 359      __THROW;
 360 # else
 361 #  ifdef __REDIRECT_NTH
 362 extern int __REDIRECT_NTH (timer_settime, (timer_t __timerid, int __flags,
 363      const struct itimerspec *__restrict __value,
 364      struct itimerspec *__restrict __ovalue),
 365                           __timer_settime64);
 366
 367 extern int __REDIRECT_NTH (timer_gettime, (timer_t __timerid,
 368                                            struct itimerspec *__value),
 369                            __timer_gettime64);
 370 #  else
 371 #   define timer_settime __timer_settime64
 372 #   define timer_gettime __timer_gettime64
 373 #  endif
 374 # endif
 375
 376 /* Get expiration overrun for timer TIMERID.  */
 377 extern int timer_getoverrun (timer_t __timerid) __THROW;
 378 #endif
 379
 380
 381 #ifdef __USE_ISOC11
 382 # ifndef __USE_TIME_BITS64
 383 /* Set TS to calendar time based in time base BASE.  */
 384 extern int timespec_get (struct timespec *__ts, int __base)
 385      __THROW __nonnull ((1));
 386 # else
 387 #  ifdef __REDIRECT_NTH
 388 extern int __REDIRECT_NTH (timespec_get, (struct timespec *__ts, int __base),
 389                            __timespec_get64) __nonnull ((1));
 390 #  else
 391 #   define timespec_get __timespec_get64
 392 #  endif
 393 # endif
 394 #endif
 395
 396
 397 #if __GLIBC_USE (ISOC2X)
 398 # ifndef __USE_TIME_BITS64
 399 /* Set TS to resolution of time base BASE.  */
 400 extern int timespec_getres (struct timespec *__ts, int __base)
 401      __THROW;
 402 # else
 403 #  ifdef __REDIRECT_NTH
 404 extern int __REDIRECT_NTH (timespec_getres, (struct timespec *__ts,
 405                                              int __base),
 406                            __timespec_getres64);
 407 #  else
 408 #   define timespec_getres __timespec_getres64
 409 #  endif
 410 # endif
 411 #endif
 412
 413
 414 #ifdef __USE_XOPEN_EXTENDED
 415 /* Set to one of the following values to indicate an error.
 416      1  the DATEMSK environment variable is null or undefined,
 417      2  the template file cannot be opened for reading,
 418      3  failed to get file status information,
 419      4  the template file is not a regular file,
 420      5  an error is encountered while reading the template file,
 421      6  memory allication failed (not enough memory available),
 422      7  there is no line in the template that matches the input,
 423      8  invalid input specification Example: February 31 or a time is
 424         specified that can not be represented in a time_t (representing
 425         the time in seconds since 00:00:00 UTC, January 1, 1970) */
 426 extern int getdate_err;
 427
 428 /* Parse the given string as a date specification and return a value
 429    representing the value.  The templates from the file identified by
 430    the environment variable DATEMSK are used.  In case of an error
 431    `getdate_err' is set.
 432
 433    This function is a possible cancellation point and therefore not
 434    marked with __THROW.  */
 435 extern struct tm *getdate (const char *__string);
 436 #endif
 437
 438 #ifdef __USE_GNU
 439 /* Since `getdate' is not reentrant because of the use of `getdate_err'
 440    and the static buffer to return the result in, we provide a thread-safe
 441    variant.  The functionality is the same.  The result is returned in
 442    the buffer pointed to by RESBUFP and in case of an error the return
 443    value is != 0 with the same values as given above for `getdate_err'.
 444
 445    This function is not part of POSIX and therefore no official
 446    cancellation point.  But due to similarity with an POSIX interface
 447    or due to the implementation it is a cancellation point and
 448    therefore not marked with __THROW.  */
 449 extern int getdate_r (const char *__restrict __string,
 450                       struct tm *__restrict __resbufp);
 451 #endif
 452
 453 __END_DECLS
 454
 455 #endif /* time.h.  */