time/time.h

   1 /* Copyright (C) 1991-2017 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    <http://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 <xlocale.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 __BEGIN_NAMESPACE_STD
  71 /* Time used by the program so far (user time + system time).
  72    The result / CLOCKS_PER_SECOND is program time in seconds.  */
  73 extern clock_t clock (void) __THROW;
  74
  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
  85
  86 /* Format TP into S according to FORMAT.
  87    Write no more than MAXSIZE characters and return the number
  88    of characters written, or 0 if it would exceed MAXSIZE.  */
  89 extern size_t strftime (char *__restrict __s, size_t __maxsize,
  90                         const char *__restrict __format,
  91                         const struct tm *__restrict __tp) __THROW;
  92 __END_NAMESPACE_STD
  93
  94 #ifdef __USE_XOPEN
  95 /* Parse S according to FORMAT and store binary time information in TP.
  96    The return value is a pointer to the first unparsed character in S.  */
  97 extern char *strptime (const char *__restrict __s,
  98                        const char *__restrict __fmt, struct tm *__tp)
  99      __THROW;
 100 #endif
 101
 102 #ifdef __USE_XOPEN2K8
 103 /* Similar to the two functions above but take the information from
 104    the provided locale and not the global locale.  */
 105
 106 extern size_t strftime_l (char *__restrict __s, size_t __maxsize,
 107                           const char *__restrict __format,
 108                           const struct tm *__restrict __tp,
 109                           __locale_t __loc) __THROW;
 110 #endif
 111
 112 #ifdef __USE_GNU
 113 extern char *strptime_l (const char *__restrict __s,
 114                          const char *__restrict __fmt, struct tm *__tp,
 115                          __locale_t __loc) __THROW;
 116 #endif
 117
 118
 119 __BEGIN_NAMESPACE_STD
 120 /* Return the `struct tm' representation of *TIMER
 121    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 122 extern struct tm *gmtime (const time_t *__timer) __THROW;
 123
 124 /* Return the `struct tm' representation
 125    of *TIMER in the local timezone.  */
 126 extern struct tm *localtime (const time_t *__timer) __THROW;
 127 __END_NAMESPACE_STD
 128
 129 #ifdef __USE_POSIX
 130 /* Return the `struct tm' representation of *TIMER in UTC,
 131    using *TP to store the result.  */
 132 extern struct tm *gmtime_r (const time_t *__restrict __timer,
 133                             struct tm *__restrict __tp) __THROW;
 134
 135 /* Return the `struct tm' representation of *TIMER in local time,
 136    using *TP to store the result.  */
 137 extern struct tm *localtime_r (const time_t *__restrict __timer,
 138                                struct tm *__restrict __tp) __THROW;
 139 #endif  /* POSIX */
 140
 141 __BEGIN_NAMESPACE_STD
 142 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 143    that is the representation of TP in this format.  */
 144 extern char *asctime (const struct tm *__tp) __THROW;
 145
 146 /* Equivalent to `asctime (localtime (timer))'.  */
 147 extern char *ctime (const time_t *__timer) __THROW;
 148 __END_NAMESPACE_STD
 149
 150 #ifdef __USE_POSIX
 151 /* Reentrant versions of the above functions.  */
 152
 153 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 154    that is the representation of TP in this format.  */
 155 extern char *asctime_r (const struct tm *__restrict __tp,
 156                         char *__restrict __buf) __THROW;
 157
 158 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 159 extern char *ctime_r (const time_t *__restrict __timer,
 160                       char *__restrict __buf) __THROW;
 161 #endif  /* POSIX */
 162
 163
 164 /* Defined in localtime.c.  */
 165 extern char *__tzname[2];       /* Current timezone names.  */
 166 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 167 extern long int __timezone;     /* Seconds west of UTC.  */
 168
 169
 170 #ifdef  __USE_POSIX
 171 /* Same as above.  */
 172 extern char *tzname[2];
 173
 174 /* Set time conversion information from the TZ environment variable.
 175    If TZ is not defined, a locale-dependent default is used.  */
 176 extern void tzset (void) __THROW;
 177 #endif
 178
 179 #if defined __USE_MISC || defined __USE_XOPEN
 180 extern int daylight;
 181 extern long int timezone;
 182 #endif
 183
 184 #ifdef __USE_MISC
 185 /* Set the system time to *WHEN.
 186    This call is restricted to the superuser.  */
 187 extern int stime (const time_t *__when) __THROW;
 188 #endif
 189
 190
 191 /* Nonzero if YEAR is a leap year (every 4 years,
 192    except every 100th isn't, and every 400th is).  */
 193 #define __isleap(year)  \
 194   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 195
 196
 197 #ifdef __USE_MISC
 198 /* Miscellaneous functions many Unices inherited from the public domain
 199    localtime package.  These are included only for compatibility.  */
 200
 201 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 202 extern time_t timegm (struct tm *__tp) __THROW;
 203
 204 /* Another name for `mktime'.  */
 205 extern time_t timelocal (struct tm *__tp) __THROW;
 206
 207 /* Return the number of days in YEAR.  */
 208 extern int dysize (int __year) __THROW  __attribute__ ((__const__));
 209 #endif
 210
 211
 212 #ifdef __USE_POSIX199309
 213 /* Pause execution for a number of nanoseconds.
 214
 215    This function is a cancellation point and therefore not marked with
 216    __THROW.  */
 217 extern int nanosleep (const struct timespec *__requested_time,
 218                       struct timespec *__remaining);
 219
 220
 221 /* Get resolution of clock CLOCK_ID.  */
 222 extern int clock_getres (clockid_t __clock_id, struct timespec *__res) __THROW;
 223
 224 /* Get current value of clock CLOCK_ID and store it in TP.  */
 225 extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp) __THROW;
 226
 227 /* Set clock CLOCK_ID to value TP.  */
 228 extern int clock_settime (clockid_t __clock_id, const struct timespec *__tp)
 229      __THROW;
 230
 231 # ifdef __USE_XOPEN2K
 232 /* High-resolution sleep with the specified clock.
 233
 234    This function is a cancellation point and therefore not marked with
 235    __THROW.  */
 236 extern int clock_nanosleep (clockid_t __clock_id, int __flags,
 237                             const struct timespec *__req,
 238                             struct timespec *__rem);
 239
 240 /* Return clock ID for CPU-time clock.  */
 241 extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __THROW;
 242 # endif
 243
 244
 245 /* Create new per-process timer using CLOCK_ID.  */
 246 extern int timer_create (clockid_t __clock_id,
 247                          struct sigevent *__restrict __evp,
 248                          timer_t *__restrict __timerid) __THROW;
 249
 250 /* Delete timer TIMERID.  */
 251 extern int timer_delete (timer_t __timerid) __THROW;
 252
 253 /* Set timer TIMERID to VALUE, returning old value in OVALUE.  */
 254 extern int timer_settime (timer_t __timerid, int __flags,
 255                           const struct itimerspec *__restrict __value,
 256                           struct itimerspec *__restrict __ovalue) __THROW;
 257
 258 /* Get current value of timer TIMERID and store it in VALUE.  */
 259 extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
 260      __THROW;
 261
 262 /* Get expiration overrun for timer TIMERID.  */
 263 extern int timer_getoverrun (timer_t __timerid) __THROW;
 264 #endif
 265
 266
 267 #ifdef __USE_ISOC11
 268 /* Set TS to calendar time based in time base BASE.  */
 269 extern int timespec_get (struct timespec *__ts, int __base)
 270      __THROW __nonnull ((1));
 271 #endif
 272
 273
 274 #ifdef __USE_XOPEN_EXTENDED
 275 /* Set to one of the following values to indicate an error.
 276      1  the DATEMSK environment variable is null or undefined,
 277      2  the template file cannot be opened for reading,
 278      3  failed to get file status information,
 279      4  the template file is not a regular file,
 280      5  an error is encountered while reading the template file,
 281      6  memory allication failed (not enough memory available),
 282      7  there is no line in the template that matches the input,
 283      8  invalid input specification Example: February 31 or a time is
 284         specified that can not be represented in a time_t (representing
 285         the time in seconds since 00:00:00 UTC, January 1, 1970) */
 286 extern int getdate_err;
 287
 288 /* Parse the given string as a date specification and return a value
 289    representing the value.  The templates from the file identified by
 290    the environment variable DATEMSK are used.  In case of an error
 291    `getdate_err' is set.
 292
 293    This function is a possible cancellation point and therefore not
 294    marked with __THROW.  */
 295 extern struct tm *getdate (const char *__string);
 296 #endif
 297
 298 #ifdef __USE_GNU
 299 /* Since `getdate' is not reentrant because of the use of `getdate_err'
 300    and the static buffer to return the result in, we provide a thread-safe
 301    variant.  The functionality is the same.  The result is returned in
 302    the buffer pointed to by RESBUFP and in case of an error the return
 303    value is != 0 with the same values as given above for `getdate_err'.
 304
 305    This function is not part of POSIX and therefore no official
 306    cancellation point.  But due to similarity with an POSIX interface
 307    or due to the implementation it is a cancellation point and
 308    therefore not marked with __THROW.  */
 309 extern int getdate_r (const char *__restrict __string,
 310                       struct tm *__restrict __resbufp);
 311 #endif
 312
 313 __END_DECLS
 314
 315 #endif /* time.h.  */