time/time.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 /*
  20  *      ISO C Standard: 4.12 DATE and TIME      <time.h>
  21  */
  22
  23 #ifndef _TIME_H
  24
  25 #if     (! defined (__need_time_t) && !defined (__need_clock_t) && \
  26          ! defined (__need_timespec))
  27 #define _TIME_H         1
  28 #include <features.h>
  29
  30 __BEGIN_DECLS
  31
  32 #endif
  33
  34 #ifdef  _TIME_H
  35 /* Get size_t and NULL from <stddef.h>.  */
  36 #define __need_size_t
  37 #define __need_NULL
  38 #include <stddef.h>
  39 #endif /* <time.h> included.  */
  40
  41
  42
  43 #ifdef  _TIME_H
  44
  45 /* This defines CLOCKS_PER_SEC, which is the number of processor clock
  46    ticks per second.  */
  47 #include <timebits.h>
  48
  49 /* This is the obsolete POSIX.1-1988 name for the same constant.  */
  50 #ifdef  __USE_POSIX
  51 #ifndef CLK_TCK
  52 #define CLK_TCK         CLOCKS_PER_SEC
  53 #endif
  54 #endif
  55
  56 #endif /* <time.h> included.  */
  57
  58
  59 #if     !defined (__clock_t_defined) &&                 \
  60         (defined (_TIME_H) || defined (__need_clock_t))
  61 #define __clock_t_defined       1
  62
  63 #include <gnu/types.h>
  64
  65 /* Returned by `clock'.  */
  66 typedef __clock_t clock_t;
  67
  68 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  69 #undef  __need_clock_t
  70
  71 #if     !defined (__time_t_defined) &&                  \
  72         (defined (_TIME_H) || defined (__need_time_t))
  73 #define __time_t_defined        1
  74
  75 #include <gnu/types.h>
  76
  77 /* Returned by `time'.  */
  78 typedef __time_t time_t;
  79
  80 #endif /* time_t not defined and <time.h> or need time_t.  */
  81 #undef  __need_time_t
  82
  83
  84 #if     ! defined (__timespec_defined) &&                       \
  85         ((defined (_TIME_H) && defined (__USE_POSIX)) ||        \
  86          defined (__need_timespec))
  87 #define __timespec_defined      1
  88
  89 /* POSIX.4 structure for a time value.  This is like a `struct timeval' but
  90    has nanoseconds instead of microseconds.  */
  91 struct timespec
  92   {
  93     long int tv_sec;            /* Seconds.  */
  94     long int tv_nsec;           /* Nanoseconds.  */
  95   };
  96
  97 #endif /* timespec not defined and <time.h> or need timespec.  */
  98 #undef  __need_timespec
  99
 100
 101
 102 #ifdef  _TIME_H
 103 /* Used by other time functions.  */
 104 struct tm
 105 {
 106   int tm_sec;                   /* Seconds.     [0-60] (1 leap second) */
 107   int tm_min;                   /* Minutes.     [0-59] */
 108   int tm_hour;                  /* Hours.       [0-23] */
 109   int tm_mday;                  /* Day.         [1-31] */
 110   int tm_mon;                   /* Month.       [0-11] */
 111   int tm_year;                  /* Year - 1900.  */
 112   int tm_wday;                  /* Day of week. [0-6] */
 113   int tm_yday;                  /* Days in year.[0-365] */
 114   int tm_isdst;                 /* DST.         [-1/0/1]*/
 115
 116 #ifdef  __USE_BSD
 117   long int tm_gmtoff;           /* Seconds east of UTC.  */
 118   __const char *tm_zone;        /* Timezone abbreviation.  */
 119 #else
 120   long int __tm_gmtoff;         /* Seconds east of UTC.  */
 121   __const char *__tm_zone;      /* Timezone abbreviation.  */
 122 #endif
 123 };
 124
 125 #endif /* <time.h> included.  */
 126
 127
 128 #ifdef  _TIME_H
 129 /* Time used by the program so far (user time + system time).
 130    The result / CLOCKS_PER_SECOND is program time in seconds.  */
 131 extern clock_t clock __P ((void));
 132
 133 /* Return the current time and put it in *TIMER if TIMER is not NULL.  */
 134 extern time_t time __P ((time_t *__timer));
 135
 136 /* Return the difference between TIME1 and TIME0.  */
 137 extern double difftime __P ((time_t __time1, time_t __time0))
 138      __attribute__ ((__const__));
 139
 140 /* Return the `time_t' representation of TP and normalize TP.  */
 141 extern time_t mktime __P ((struct tm *__tp));
 142
 143 /* Subroutine of `mktime'.  Return the `time_t' representation of TP and
 144    normalize TP, given that a `struct tm *' maps to a `time_t' as performed
 145    by FUNC.  Keep track of next guess for time_t offset in *OFFSET.  */
 146 extern time_t __mktime_internal __P ((struct tm *__tp,
 147                                       struct tm *(*__func) (const time_t *,
 148                                                             struct tm *),
 149                                       time_t *__offset));
 150
 151
 152 /* Format TP into S according to FORMAT.
 153    Write no more than MAXSIZE characters and return the number
 154    of characters written, or 0 if it would exceed MAXSIZE.  */
 155 extern size_t strftime __P ((char *__restrict __s, size_t __maxsize,
 156                              __const char *__restrict __format,
 157                              __const struct tm *__restrict __tp));
 158
 159 #ifdef __USE_XOPEN
 160 /* Parse S according to FORMAT and store binary time information in TP.
 161    The return value is a pointer to the first unparsed character in S.  */
 162 extern char *strptime __P ((__const char *__s, __const char *__fmt,
 163                             struct tm *__tp));
 164 #endif
 165
 166
 167 /* Return the `struct tm' representation of *TIMER
 168    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 169 extern struct tm *gmtime __P ((__const time_t *__timer));
 170
 171 /* Return the `struct tm' representation
 172    of *TIMER in the local timezone.  */
 173 extern struct tm *localtime __P ((__const time_t *__timer));
 174
 175 #if defined __USE_POSIX || defined __USE_MISC
 176 /* Return the `struct tm' representation of *TIMER in UTC,
 177    using *TP to store the result.  */
 178 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
 179                                    struct tm *__tp));
 180 extern struct tm *gmtime_r __P ((__const time_t *__timer,
 181                                  struct tm *__tp));
 182
 183 /* Return the `struct tm' representation of *TIMER in local time,
 184    using *TP to store the result.  */
 185 extern struct tm *__localtime_r __P ((__const time_t *__timer,
 186                                       struct tm *__tp));
 187 extern struct tm *localtime_r __P ((__const time_t *__timer,
 188                                     struct tm *__tp));
 189 #endif  /* POSIX or misc */
 190
 191 /* Compute the `struct tm' representation of *T,
 192    offset OFFSET seconds east of UTC,
 193    and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
 194 extern void __offtime __P ((__const time_t *__timer,
 195                             long int __offset,
 196                             struct tm *__TP));
 197
 198 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 199    that is the representation of TP in this format.  */
 200 extern char *asctime __P ((__const struct tm *__tp));
 201
 202 /* Equivalent to `asctime (localtime (timer))'.  */
 203 extern char *ctime __P ((__const time_t *__timer));
 204
 205 #if defined __USE_POSIX || defined __USE_MISC
 206 /* Reentrant versions of the above functions.  */
 207
 208 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 209    that is the representation of TP in this format.  */
 210 extern char *__asctime_r __P ((__const struct tm *__tp, char *__buf));
 211 extern char *asctime_r __P ((__const struct tm *__tp, char *__buf));
 212
 213 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 214 extern char *ctime_r __P ((__const time_t *__timer, char *__buf));
 215 #endif  /* POSIX or misc */
 216
 217
 218 /* Defined in localtime.c.  */
 219 extern char *__tzname[2];       /* Current timezone names.  */
 220 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 221 extern long int __timezone;     /* Seconds west of UTC.  */
 222
 223 /* Set time conversion information from the TZ environment variable.
 224    If TZ is not defined, a locale-dependent default is used.  */
 225 extern void __tzset __P ((void));
 226
 227 #ifdef  __USE_POSIX
 228 /* Same as above.  */
 229 extern char *tzname[2];
 230
 231 /* Return the maximum length of a timezone name.
 232    This is what `sysconf (_SC_TZNAME_MAX)' does.  */
 233 extern long int __tzname_max __P ((void));
 234
 235 extern void tzset __P ((void));
 236 #endif
 237
 238 #if defined(__USE_SVID) || defined(__USE_XOPEN)
 239 extern int daylight;
 240 extern long int timezone;
 241 #endif
 242
 243 #ifdef __USE_SVID
 244 /* Set the system time to *WHEN.
 245    This call is restricted to the superuser.  */
 246 extern int stime __P ((__const time_t *__when));
 247 #endif
 248
 249
 250 /* Nonzero if YEAR is a leap year (every 4 years,
 251    except every 100th isn't, and every 400th is).  */
 252 #define __isleap(year)  \
 253   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 254
 255
 256 #ifdef __USE_MISC
 257 /* Miscellaneous functions many Unices inherited from the public domain
 258    localtime package.  These are included only for compatibility.  */
 259
 260 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 261 extern time_t timegm __P ((struct tm *__tp));
 262
 263 /* Another name for `mktime'.  */
 264 extern time_t timelocal __P ((struct tm *__tp));
 265
 266 /* Return the number of days in YEAR.  */
 267 extern int dysize __P ((int __year));
 268 #endif
 269
 270
 271 #ifdef __USE_POSIX199309
 272 /* Pause execution for a number of nanoseconds.  */
 273 extern int __nanosleep __P ((__const struct timespec *__requested_time,
 274                              struct timespec *__remaining));
 275 extern int nanosleep __P ((__const struct timespec *__requested_time,
 276                            struct timespec *__remaining));
 277 #endif
 278
 279
 280 __END_DECLS
 281
 282 #endif /* <time.h> included.  */
 283
 284 #endif /* <time.h> not already included.  */