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 && (defined _TIME_H || defined __need_clock_t)
  60 #define __clock_t_defined       1
  61
  62 #include <gnu/types.h>
  63
  64 /* Returned by `clock'.  */
  65 typedef __clock_t clock_t;
  66
  67 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  68 #undef  __need_clock_t
  69
  70 #if !defined __time_t_defined && (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 *__restrict __s, size_t __maxsize,
 154                              __const char *__restrict __format,
 155                              __const struct tm *__restrict __tp));
 156
 157 #ifdef __USE_XOPEN
 158 /* Parse S according to FORMAT and store binary time information in TP.
 159    The return value is a pointer to the first unparsed character in S.  */
 160 extern char *strptime __P ((__const char *__s, __const char *__fmt,
 161                             struct tm *__tp));
 162 #endif
 163
 164
 165 /* Return the `struct tm' representation of *TIMER
 166    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 167 extern struct tm *gmtime __P ((__const time_t *__timer));
 168
 169 /* Return the `struct tm' representation
 170    of *TIMER in the local timezone.  */
 171 extern struct tm *localtime __P ((__const time_t *__timer));
 172
 173 #if defined __USE_POSIX || defined __USE_MISC
 174 /* Return the `struct tm' representation of *TIMER in UTC,
 175    using *TP to store the result.  */
 176 extern struct tm *__gmtime_r __P ((__const time_t *__timer,
 177                                    struct tm *__tp));
 178 extern struct tm *gmtime_r __P ((__const time_t *__timer,
 179                                  struct tm *__tp));
 180
 181 /* Return the `struct tm' representation of *TIMER in local time,
 182    using *TP to store the result.  */
 183 extern struct tm *__localtime_r __P ((__const time_t *__timer,
 184                                       struct tm *__tp));
 185 extern struct tm *localtime_r __P ((__const time_t *__timer,
 186                                     struct tm *__tp));
 187 #endif  /* POSIX or misc */
 188
 189 /* Compute the `struct tm' representation of *T,
 190    offset OFFSET seconds east of UTC,
 191    and store year, yday, mon, mday, wday, hour, min, sec into *TP.  */
 192 extern void __offtime __P ((__const time_t *__timer,
 193                             long int __offset,
 194                             struct tm *__TP));
 195
 196 /* Return 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 __P ((__const struct tm *__tp));
 199
 200 /* Equivalent to `asctime (localtime (timer))'.  */
 201 extern char *ctime __P ((__const time_t *__timer));
 202
 203 #if defined __USE_POSIX || defined __USE_MISC
 204 /* Reentrant versions of the above functions.  */
 205
 206 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 207    that is the representation of TP in this format.  */
 208 extern char *__asctime_r __P ((__const struct tm *__tp, char *__buf));
 209 extern char *asctime_r __P ((__const struct tm *__tp, char *__buf));
 210
 211 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 212 extern char *ctime_r __P ((__const time_t *__timer, char *__buf));
 213 #endif  /* POSIX or misc */
 214
 215
 216 /* Defined in localtime.c.  */
 217 extern char *__tzname[2];       /* Current timezone names.  */
 218 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 219 extern long int __timezone;     /* Seconds west of UTC.  */
 220
 221 /* Set time conversion information from the TZ environment variable.
 222    If TZ is not defined, a locale-dependent default is used.  */
 223 extern void __tzset __P ((void));
 224
 225 #ifdef  __USE_POSIX
 226 /* Same as above.  */
 227 extern char *tzname[2];
 228
 229 /* Return the maximum length of a timezone name.
 230    This is what `sysconf (_SC_TZNAME_MAX)' does.  */
 231 extern long int __tzname_max __P ((void));
 232
 233 extern void tzset __P ((void));
 234 #endif
 235
 236 #if defined __USE_SVID || defined __USE_XOPEN
 237 extern int daylight;
 238 extern long int timezone;
 239 #endif
 240
 241 #ifdef __USE_SVID
 242 /* Set the system time to *WHEN.
 243    This call is restricted to the superuser.  */
 244 extern int stime __P ((__const time_t *__when));
 245 #endif
 246
 247
 248 /* Nonzero if YEAR is a leap year (every 4 years,
 249    except every 100th isn't, and every 400th is).  */
 250 #define __isleap(year)  \
 251   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 252
 253
 254 #ifdef __USE_MISC
 255 /* Miscellaneous functions many Unices inherited from the public domain
 256    localtime package.  These are included only for compatibility.  */
 257
 258 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 259 extern time_t timegm __P ((struct tm *__tp));
 260
 261 /* Another name for `mktime'.  */
 262 extern time_t timelocal __P ((struct tm *__tp));
 263
 264 /* Return the number of days in YEAR.  */
 265 extern int dysize __P ((int __year));
 266 #endif
 267
 268
 269 #ifdef __USE_POSIX199309
 270 /* Pause execution for a number of nanoseconds.  */
 271 extern int __nanosleep __P ((__const struct timespec *__requested_time,
 272                              struct timespec *__remaining));
 273 extern int nanosleep __P ((__const struct timespec *__requested_time,
 274                            struct timespec *__remaining));
 275 #endif
 276
 277
 278 __END_DECLS
 279
 280 #endif /* <time.h> included.  */
 281
 282 #endif /* <time.h> not already included.  */