time/time.h

   1 /* Copyright (C) 1991, 1992, 1993, 1994, 1995 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, 1992 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 #define _TIME_H         1
  27 #include <features.h>
  28
  29 __BEGIN_DECLS
  30
  31 #endif
  32
  33 #ifdef  _TIME_H
  34 /* Get size_t and NULL from <stddef.h>.  */
  35 #define __need_size_t
  36 #define __need_NULL
  37 #include <stddef.h>
  38 #endif /* <time.h> included.  */
  39
  40
  41
  42 #ifdef  _TIME_H
  43 /* Processor clock ticks per second.  */
  44 #define CLOCKS_PER_SEC  1       /* ??? */
  45
  46 #ifdef  __USE_POSIX
  47 #define CLK_TCK         60      /* ??? */
  48 #endif
  49
  50 #endif /* <time.h> included.  */
  51
  52
  53 #if     !defined(__clock_t_defined) &&                  \
  54         (defined(_TIME_H) || defined(__need_clock_t))
  55 #define __clock_t_defined       1
  56
  57 /* Returned by `clock'.  */
  58 typedef long int clock_t;
  59
  60 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  61 #undef  __need_clock_t
  62
  63 #if     !defined(__time_t_defined) &&                   \
  64         (defined(_TIME_H) || defined(__need_time_t))
  65 #define __time_t_defined        1
  66
  67 #include <gnu/types.h>
  68
  69 /* Returned by `time'.  */
  70 typedef __time_t time_t;
  71
  72 #endif /* time_t not defined and <time.h> or need time_t.  */
  73 #undef  __need_time_t
  74
  75
  76 #ifdef  _TIME_H
  77 /* Used by other time functions.  */
  78 struct tm
  79 {
  80   int tm_sec;                   /* Seconds.     [0-61] (2 leap seconds) */
  81   int tm_min;                   /* Minutes.     [0-59] */
  82   int tm_hour;                  /* Hours.       [0-23] */
  83   int tm_mday;                  /* Day.         [1-31] */
  84   int tm_mon;                   /* Month.       [0-11] */
  85   int tm_year;                  /* Year - 1900.  */
  86   int tm_wday;                  /* Day of week. [0-6] */
  87   int tm_yday;                  /* Days in year.[0-365] */
  88   int tm_isdst;                 /* DST.         [-1/0/1]*/
  89   long int tm_gmtoff;           /* Seconds west of UTC.  */
  90   __const char *tm_zone;        /* Timezone abbreviation.  */
  91 };
  92
  93 #endif /* <time.h> included.  */
  94
  95
  96 #ifdef  _TIME_H
  97 /* Time used by the program so far (user time + system time).
  98    The result / CLOCKS_PER_SECOND is program time in seconds.  */
  99 extern clock_t clock __P ((void));
 100
 101 /* Return the current time and put it in *TIMER if TIMER is not NULL.  */
 102 extern time_t time __P ((time_t *__timer));
 103
 104 /* Return the difference between TIME1 and TIME0.  */
 105 extern double difftime __P ((time_t __time1, time_t __time0))
 106      __attribute__ ((__const__));
 107
 108 /* Return the `time_t' representation of TP and normalize TP.  */
 109 extern time_t mktime __P ((struct tm *__tp));
 110
 111 /* Subroutine of `mktime'.  Return the `time_t' representation of TP and
 112    normalize TP, given that a `struct tm *' maps to a `time_t' as performed
 113    by FUNC.  Keep track of next guess for time_t offset in *OFFSET.  */
 114 extern time_t __mktime_internal __P ((struct tm *__tp,
 115                                       struct tm *(*__func) (const time_t *,
 116                                                             struct tm *),
 117                                       time_t *__offset));
 118
 119
 120 /* Format TP into S according to FORMAT.
 121    Write no more than MAXSIZE characters and return the number
 122    of characters written, or 0 if it would exceed MAXSIZE.  */
 123 extern size_t strftime __P ((char *__s, size_t __maxsize,
 124                          __const char *__format, __const struct tm *__tp));
 125
 126
 127 /* Return the `struct tm' representation of *TIMER
 128    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 129 extern struct tm *gmtime __P ((__const time_t *__timer));
 130
 131 /* Return the `struct tm' representation
 132    of *TIMER in the local timezone.  */
 133 extern struct tm *localtime __P ((__const time_t *__timer));
 134
 135 #ifdef  __USE_REENTRANT
 136 /* Return the `struct tm' representation of *TIMER in UTC,
 137    using *TP to store the result.  */
 138 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
 139                                    struct tm *__tp));
 140 extern struct tm *gmtime_r __P ((__const time_t *__timer,
 141                                  struct tm *__tp));
 142
 143 /* Return the `struct tm' representation of *TIMER in local time,
 144    using *TP to store the result.  */
 145 extern struct tm *__localtime_r __P ((__const time_t *__timer,
 146                                       struct tm *__tp));
 147 extern struct tm *localtime_r __P ((__const time_t *__timer,
 148                                     struct tm *__tp));
 149 #endif
 150
 151 /* Compute the `struct tm' representation of *T,
 152    offset OFFSET seconds east of UTC,
 153    and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
 154 extern void __offtime __P ((__const time_t *__timer,
 155                             long int __offset,
 156                             struct tm *__TP));
 157
 158 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 159    that is the representation of TP in this format.  */
 160 extern char *asctime __P ((__const struct tm *__tp));
 161
 162 /* Equivalent to `asctime(localtime(timer))'.  */
 163 extern char *ctime __P ((__const time_t *__timer));
 164
 165
 166 /* Defined in localtime.c.  */
 167 extern char *__tzname[2];       /* Current timezone names.  */
 168 extern int __daylight;          /* If it is daylight savings time.  */
 169 extern long int __timezone;     /* Seconds west of UTC.  */
 170
 171 /* Set time conversion information from the TZ environment variable.
 172    If TZ is not defined, a locale-dependent default is used.  */
 173 extern void __tzset __P ((void));
 174
 175 #ifdef  __USE_POSIX
 176 /* Same as above.  */
 177 extern char *tzname[2];
 178
 179 /* Return the maximum length of a timezone name.
 180    This is what `sysconf (_SC_TZNAME_MAX)' does.  */
 181 extern long int __tzname_max __P ((void));
 182
 183 extern void tzset __P ((void));
 184 #ifdef  __OPTIMIZE__
 185 #define tzset() __tzset()
 186 #endif /* Optimizing.  */
 187 #endif
 188
 189 #ifdef  __USE_SVID
 190 extern int daylight;
 191 extern long int timezone;
 192
 193 /* Set the system time to *WHEN.
 194    This call is restricted to the superuser.  */
 195 extern int stime __P ((__const time_t *__when));
 196 #endif
 197
 198
 199 /* Nonzero if YEAR is a leap year (every 4 years,
 200    except every 100th isn't, and every 400th is).  */
 201 #define __isleap(year)  \
 202   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 203
 204
 205 #ifdef __USE_MISC
 206 /* Miscellaneous functions many Unices inherited from the public domain
 207    localtime package.  These are included only for compatibility.  */
 208
 209 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 210 extern time_t timegm __P ((struct tm *__tp));
 211
 212 /* Another name for `mktime'.  */
 213 extern time_t timelocal __P ((struct tm *__tp));
 214
 215 /* Return the number of days in YEAR.  */
 216 extern int dysize __P ((int __year));
 217 #endif
 218
 219
 220 __END_DECLS
 221
 222 #endif /* <time.h> included.  */
 223
 224 #endif /* <time.h> not already included.  */