time/time.h

   1 /* Copyright (C) 1991,92,93,94,95,96,97,98,99 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
  40 /* This defines CLOCKS_PER_SEC, which is the number of processor clock
  41    ticks per second.  */
  42 # include <bits/time.h>
  43
  44 /* This is the obsolete POSIX.1-1988 name for the same constant.  */
  45 # ifdef __USE_POSIX
  46 #  ifndef CLK_TCK
  47 #   define CLK_TCK      CLOCKS_PER_SEC
  48 #  endif
  49 # endif
  50
  51 #endif /* <time.h> included.  */
  52
  53
  54 #if !defined __clock_t_defined && (defined _TIME_H || defined __need_clock_t)
  55 # define __clock_t_defined      1
  56
  57 # include <bits/types.h>
  58
  59 /* Returned by `clock'.  */
  60 typedef __clock_t clock_t;
  61
  62 #endif /* clock_t not defined and <time.h> or need clock_t.  */
  63 #undef  __need_clock_t
  64
  65 #if !defined __time_t_defined && (defined _TIME_H || defined __need_time_t)
  66 # define __time_t_defined       1
  67
  68 # include <bits/types.h>
  69
  70 /* Returned by `time'.  */
  71 typedef __time_t time_t;
  72
  73 #endif /* time_t not defined and <time.h> or need time_t.  */
  74 #undef  __need_time_t
  75
  76
  77 #if !defined __timespec_defined && \
  78     ((defined _TIME_H && defined __USE_POSIX199309) || defined __need_timespec)
  79 # define __timespec_defined     1
  80
  81 /* POSIX.4 structure for a time value.  This is like a `struct timeval' but
  82    has nanoseconds instead of microseconds.  */
  83 struct timespec
  84   {
  85     long int tv_sec;            /* Seconds.  */
  86     long int tv_nsec;           /* Nanoseconds.  */
  87   };
  88
  89 #endif /* timespec not defined and <time.h> or need timespec.  */
  90 #undef  __need_timespec
  91
  92
  93 #ifdef  _TIME_H
  94 /* Used by other time functions.  */
  95 struct tm
  96 {
  97   int tm_sec;                   /* Seconds.     [0-60] (1 leap second) */
  98   int tm_min;                   /* Minutes.     [0-59] */
  99   int tm_hour;                  /* Hours.       [0-23] */
 100   int tm_mday;                  /* Day.         [1-31] */
 101   int tm_mon;                   /* Month.       [0-11] */
 102   int tm_year;                  /* Year - 1900.  */
 103   int tm_wday;                  /* Day of week. [0-6] */
 104   int tm_yday;                  /* Days in year.[0-365] */
 105   int tm_isdst;                 /* DST.         [-1/0/1]*/
 106
 107 # ifdef __USE_BSD
 108   long int tm_gmtoff;           /* Seconds east of UTC.  */
 109   __const char *tm_zone;        /* Timezone abbreviation.  */
 110 # else
 111   long int __tm_gmtoff;         /* Seconds east of UTC.  */
 112   __const char *__tm_zone;      /* Timezone abbreviation.  */
 113 # endif
 114 };
 115
 116
 117 /* Time used by the program so far (user time + system time).
 118    The result / CLOCKS_PER_SECOND is program time in seconds.  */
 119 extern clock_t clock __P ((void));
 120
 121 /* Return the current time and put it in *TIMER if TIMER is not NULL.  */
 122 extern time_t time __P ((time_t *__timer));
 123
 124 /* Return the difference between TIME1 and TIME0.  */
 125 extern double difftime __P ((time_t __time1, time_t __time0))
 126      __attribute__ ((__const__));
 127
 128 /* Return the `time_t' representation of TP and normalize TP.  */
 129 extern time_t mktime __P ((struct tm *__tp));
 130
 131
 132 /* Format TP into S according to FORMAT.
 133    Write no more than MAXSIZE characters and return the number
 134    of characters written, or 0 if it would exceed MAXSIZE.  */
 135 extern size_t strftime __P ((char *__restrict __s, size_t __maxsize,
 136                              __const char *__restrict __format,
 137                              __const struct tm *__restrict __tp));
 138
 139 # ifdef __USE_XOPEN
 140 /* Parse S according to FORMAT and store binary time information in TP.
 141    The return value is a pointer to the first unparsed character in S.  */
 142 extern char *strptime __P ((__const char *__s, __const char *__fmt,
 143                             struct tm *__tp));
 144 # endif
 145
 146
 147 /* Return the `struct tm' representation of *TIMER
 148    in Universal Coordinated Time (aka Greenwich Mean Time).  */
 149 extern struct tm *gmtime __P ((__const time_t *__timer));
 150
 151 /* Return the `struct tm' representation
 152    of *TIMER in the local timezone.  */
 153 extern struct tm *localtime __P ((__const time_t *__timer));
 154
 155 # if defined __USE_POSIX || defined __USE_MISC
 156 /* Return the `struct tm' representation of *TIMER in UTC,
 157    using *TP to store the result.  */
 158 extern struct tm *__gmtime_r __P ((__const time_t *__restrict __timer,
 159                                    struct tm *__restrict __tp));
 160 extern struct tm *gmtime_r __P ((__const time_t *__restrict __timer,
 161                                  struct tm *__restrict __tp));
 162
 163 /* Return the `struct tm' representation of *TIMER in local time,
 164    using *TP to store the result.  */
 165 extern struct tm *localtime_r __P ((__const time_t *__restrict __timer,
 166                                     struct tm *__restrict __tp));
 167 # endif /* POSIX or misc */
 168
 169 /* Return a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 170    that is the representation of TP in this format.  */
 171 extern char *asctime __P ((__const struct tm *__tp));
 172
 173 /* Equivalent to `asctime (localtime (timer))'.  */
 174 extern char *ctime __P ((__const time_t *__timer));
 175
 176 # if defined __USE_POSIX || defined __USE_MISC
 177 /* Reentrant versions of the above functions.  */
 178
 179 /* Return in BUF a string of the form "Day Mon dd hh:mm:ss yyyy\n"
 180    that is the representation of TP in this format.  */
 181 extern char *asctime_r __P ((__const struct tm *__restrict __tp,
 182                              char *__restrict __buf));
 183
 184 /* Equivalent to `asctime_r (localtime_r (timer, *TMP*), buf)'.  */
 185 extern char *ctime_r __P ((__const time_t *__restrict __timer,
 186                            char *__restrict __buf));
 187 # endif /* POSIX or misc */
 188
 189
 190 /* Defined in localtime.c.  */
 191 extern char *__tzname[2];       /* Current timezone names.  */
 192 extern int __daylight;          /* If daylight-saving time is ever in use.  */
 193 extern long int __timezone;     /* Seconds west of UTC.  */
 194
 195
 196 # ifdef __USE_POSIX
 197 /* Same as above.  */
 198 extern char *tzname[2];
 199
 200 /* Set time conversion information from the TZ environment variable.
 201    If TZ is not defined, a locale-dependent default is used.  */
 202 extern void tzset __P ((void));
 203 # endif
 204
 205 # if defined __USE_SVID || defined __USE_XOPEN
 206 extern int daylight;
 207 extern long int timezone;
 208 # endif
 209
 210 # ifdef __USE_SVID
 211 /* Set the system time to *WHEN.
 212    This call is restricted to the superuser.  */
 213 extern int stime __P ((__const time_t *__when));
 214 # endif
 215
 216
 217 /* Nonzero if YEAR is a leap year (every 4 years,
 218    except every 100th isn't, and every 400th is).  */
 219 # define __isleap(year) \
 220   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 221
 222
 223 # ifdef __USE_MISC
 224 /* Miscellaneous functions many Unices inherited from the public domain
 225    localtime package.  These are included only for compatibility.  */
 226
 227 /* Like `mktime', but for TP represents Universal Time, not local time.  */
 228 extern time_t timegm __P ((struct tm *__tp));
 229
 230 /* Another name for `mktime'.  */
 231 extern time_t timelocal __P ((struct tm *__tp));
 232
 233 /* Return the number of days in YEAR.  */
 234 extern int dysize __P ((int __year));
 235 # endif
 236
 237
 238 # ifdef __USE_POSIX199309
 239 /* Pause execution for a number of nanoseconds.  */
 240 extern int nanosleep __P ((__const struct timespec *__requested_time,
 241                            struct timespec *__remaining));
 242 # endif
 243
 244
 245 # ifdef __USE_XOPEN_EXTENDED
 246 /* Set to one of the following values to indicate an error.
 247      1  the DATEMSK environment variable is null or undefined,
 248      2  the template file cannot be opened for reading,
 249      3  failed to get file status information,
 250      4  the template file is not a regular file,
 251      5  an error is encountered while reading the template file,
 252      6  memory allication failed (not enough memory available),
 253      7  there is no line in the template that matches the input,
 254      8  invalid input specification Example: February 31 or a time is
 255         specified that can not be represented in a time_t (representing
 256         the time in seconds since 00:00:00 UTC, January 1, 1970) */
 257 extern int getdate_err;
 258
 259 /* Parse the given string as a date specification and return a value
 260    representing the value.  The templates from the file identified by
 261    the environment variable DATEMSK are used.  In case of an error
 262    `getdate_err' is set.  */
 263 extern struct tm *getdate __P ((__const char *__string));
 264 # endif
 265
 266 # ifdef __USE_GNU
 267 /* Since `getdate' is not reentrant because of the use of `getdate_err'
 268    and the static buffer to return the result in, we provide a thread-safe
 269    variant.  The functionality is the same.  The result is returned in
 270    the buffer pointed to by RESBUFP and in case of an error the return
 271    value is != 0 with the same values as given above for `getdate_err'.  */
 272 extern int getdate_r __P ((__const char *__restrict __string,
 273                            struct tm *__restrict __resbufp));
 274 # endif
 275
 276
 277 __END_DECLS
 278
 279 #endif /* <time.h> included.  */
 280
 281 #endif /* <time.h> not already included.  */