time/time.h

   1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 /*
  20  *      ANSI 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 #define CLK_TCK         CLOCKS_PER_SEC
  52 #endif
  53
  54 #endif /* <time.h> included.  */
  55
  56
  57 #if     !defined (__clock_t_defined) &&                 \
  58         (defined (_TIME_H) || defined (__need_clock_t))
  59 #define __clock_t_defined       1
  60
  61 #include <gnu/types.h>
  62
  63 /* Returned by `clock'.  */
  64 typedef __clock_t clock_t;
  65
  66 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  67 #undef  __need_clock_t
  68
  69 #if     !defined (__time_t_defined) &&                  \
  70         (defined (_TIME_H) || defined (__need_time_t))
  71 #define __time_t_defined        1
  72
  73 #include <gnu/types.h>
  74
  75 /* Returned by `time'.  */
  76 typedef __time_t time_t;
  77
  78 #endif /* time_t not defined and <time.h> or need time_t.  */
  79 #undef  __need_time_t
  80
  81
  82 #if     ! defined (__timespec_defined) &&                       \
  83         ((defined (_TIME_H) && defined (__USE_POSIX)) ||        \
  84          defined (__need_timespec))
  85 #define __timespec_defined      1
  86
  87 /* POSIX.4 structure for a time value.  This is like a `struct timeval' but
  88    has nanoseconds instead of microseconds.  */
  89 struct timespec
  90   {
  91     long int tv_sec;            /* Seconds.  */
  92     long int tv_nsec;           /* Nanoseconds.  */
  93   };
  94
  95 #endif /* timespec not defined and <time.h> or need timespec.  */
  96 #undef  __need_timespec
  97
  98
  99
 100 #ifdef  _TIME_H
 101 /* Used by other time functions.  */
 102 struct tm
 103 {
 104   int tm_sec;                   /* Seconds.     [0-60] (1 leap second) */
 105   int tm_min;                   /* Minutes.     [0-59] */
 106   int tm_hour;                  /* Hours.       [0-23] */
 107   int tm_mday;                  /* Day.         [1-31] */
 108   int tm_mon;                   /* Month.       [0-11] */
 109   int tm_year;                  /* Year - 1900.  */
 110   int tm_wday;                  /* Day of week. [0-6] */
 111   int tm_yday;                  /* Days in year.[0-365] */
 112   int tm_isdst;                 /* DST.         [-1/0/1]*/
 113
 114 #ifdef  __USE_BSD
 115   long int tm_gmtoff;           /* Seconds east of UTC.  */
 116   __const char *tm_zone;        /* Timezone abbreviation.  */
 117 #else
 118   long int __tm_gmtoff;         /* Seconds east of UTC.  */
 119   __const char *__tm_zone;      /* Timezone abbreviation.  */
 120 #endif
 121 };
 122
 123 #endif /* <time.h> included.  */
 124
 125
 126 #ifdef  _TIME_H
 127 /* Time used by the program so far (user time + system time).
 128    The result / CLOCKS_PER_SECOND is program time in seconds.  */
 129 extern clock_t clock __P ((void));
 130
 131 /* Return the current time and put it in *TIMER if TIMER is not NULL.  */
 132 extern time_t time __P ((time_t *__timer));
 133
 134 /* Return the difference between TIME1 and TIME0.  */
 135 extern double difftime __P ((time_t __time1, time_t __time0))
 136      __attribute__ ((__const__));
 137
 138 /* Return the `time_t' representation of TP and normalize TP.  */
 139 extern time_t mktime __P ((struct tm *__tp));
 140
 141 /* Subroutine of `mktime'.  Return the `time_t' representation of TP and
 142    normalize TP, given that a `struct tm *' maps to a `time_t' as performed
 143    by FUNC.  Keep track of next guess for time_t offset in *OFFSET.  */
 144 extern time_t __mktime_internal __P ((struct tm *__tp,
 145                                       struct tm *(*__func) (const time_t *,
 146                                                             struct tm *),
 147                                       time_t *__offset));
 148
 149
 150 /* Format TP into S according to FORMAT.
 151    Write no more than MAXSIZE characters and return the number
 152    of characters written, or 0 if it would exceed MAXSIZE.  */
 153 extern size_t strftime __P ((char *__s, size_t __maxsize,
 154                              __const char *__format, __const struct tm *__tp));
 155
 156 #ifdef __USE_MISC
 157 /* Parse S according to FORMAT and store binary time information in TP.
 158    The return value is a pointer to the first unparsed character in S.  */
 159 extern char *strptime __P ((__const char *__s, __const char *__fmt,
 160                             struct tm *__tp));
 161 #endif
 162
 163
 164 /* Return the `struct tm' representation of *TIMER
 165    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 166 extern struct tm *gmtime __P ((__const time_t *__timer));
 167
 168 /* Return the `struct tm' representation
 169    of *TIMER in the local timezone.  */
 170 extern struct tm *localtime __P ((__const time_t *__timer));
 171
 172 #ifdef  __USE_REENTRANT
 173 /* Return the `struct tm' representation of *TIMER in UTC,
 174    using *TP to store the result.  */
 175 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
 176                                    struct tm *__tp));
 177 extern struct tm *gmtime_r __P ((__const time_t *__timer,
 178                                  struct tm *__tp));
 179
 180 /* Return the `struct tm' representation of *TIMER in local time,
 181    using *TP to store the result.  */
 182 extern struct tm *__localtime_r __P ((__const time_t *__timer,
 183                                       struct tm *__tp));
 184 extern struct tm *localtime_r __P ((__const time_t *__timer,
 185                                     struct tm *__tp));
 186 #endif  /* reentrant */
 187
 188 /* Compute the `struct tm' representation of *T,
 189    offset OFFSET seconds east of UTC,
 190    and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
 191 extern void __offtime __P ((__const time_t *__timer,
 192                             long int __offset,
 193                             struct tm *__TP));
 194
 195 /* Return 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 __P ((__const struct tm *__tp));
 198
 199 /* Equivalent to `asctime (localtime (timer))'.  */
 200 extern char *ctime __P ((__const time_t *__timer));
 201
 202 #ifdef  __USE_REENTRANT
 203 /* Reentrant versions of the above functions.  */
 204
 205 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 206    that is the representation of TP in this format.  */
 207 extern char *__asctime_r __P ((__const struct tm *__tp, char *__buf));
 208 extern char *asctime_r __P ((__const struct tm *__tp, char *__buf));
 209
 210 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 211 extern char *ctime_r __P ((__const time_t *__timer, char *__buf));
 212 #endif  /* reentrant */
 213
 214
 215 /* Defined in localtime.c.  */
 216 extern char *__tzname[2];       /* Current timezone names.  */
 217 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 218 extern long int __timezone;     /* Seconds west of UTC.  */
 219
 220 /* Set time conversion information from the TZ environment variable.
 221    If TZ is not defined, a locale-dependent default is used.  */
 222 extern void __tzset __P ((void));
 223
 224 #ifdef  __USE_POSIX
 225 /* Same as above.  */
 226 extern char *tzname[2];
 227
 228 /* Return the maximum length of a timezone name.
 229    This is what `sysconf (_SC_TZNAME_MAX)' does.  */
 230 extern long int __tzname_max __P ((void));
 231
 232 extern void tzset __P ((void));
 233 #endif
 234
 235 #ifdef  __USE_SVID
 236 extern int daylight;
 237 extern long int timezone;
 238
 239 /* Set the system time to *WHEN.
 240    This call is restricted to the superuser.  */
 241 extern int stime __P ((__const time_t *__when));
 242 #endif
 243
 244
 245 /* Nonzero if YEAR is a leap year (every 4 years,
 246    except every 100th isn't, and every 400th is).  */
 247 #define __isleap(year)  \
 248   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 249
 250
 251 #ifdef __USE_MISC
 252 /* Miscellaneous functions many Unices inherited from the public domain
 253    localtime package.  These are included only for compatibility.  */
 254
 255 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 256 extern time_t timegm __P ((struct tm *__tp));
 257
 258 /* Another name for `mktime'.  */
 259 extern time_t timelocal __P ((struct tm *__tp));
 260
 261 /* Return the number of days in YEAR.  */
 262 extern int dysize __P ((int __year));
 263 #endif
 264
 265
 266 #ifdef __USE_POSIX
 267 /* Pause execution for a number of nanoseconds.  */
 268 extern int __nanosleep __P ((__const struct timespec *__requested_time,
 269                              struct timespec *__remaining));
 270 extern int nanosleep __P ((__const struct timespec *__requested_time,
 271                            struct timespec *__remaining));
 272 #endif
 273
 274
 275 __END_DECLS
 276
 277 #endif /* <time.h> included.  */
 278
 279 #endif /* <time.h> not already included.  */