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The C and C++ Include Header Files
/usr/include/time.h
$ cat -n /usr/include/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_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 time zone abbreviations. */ 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. */
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