code.delx.au - gnu-emacs/blob - src/systime.h

   1 /* systime.h - System-dependent definitions for time manipulations.
   2    Copyright (C) 1992 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 1, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #ifdef TM_IN_SYS_TIME
  21 #include <sys/time.h>
  22 #else
  23 #include <time.h>
  24 #ifdef HAVE_SYS_TIME_H
  25 #include <sys/time.h>
  26 #endif
  27 #endif
  28
  29 /* SVr4 doesn't actually declare this in its #include files.  */
  30 #ifdef USG5_4
  31 extern long timezone;
  32 #endif
  33
  34 #ifdef VMS
  35 #ifdef VAXC
  36 #include "vmstime.h"
  37 #endif
  38 #endif
  39
  40 \f
  41 /* EMACS_TIME is the type to use to represent temporal intervals -
  42    struct timeval on some systems, int on others.  It can be passed as
  43    the timeout argument to the select  system call.
  44
  45    EMACS_SECS (TIME) is an rvalue for the seconds component of TIME.
  46    EMACS_SET_SECS (TIME, SECONDS) sets that to SECONDS.
  47
  48    EMACS_HAS_USECS is defined iff EMACS_TIME has a usecs component.
  49    EMACS_USECS (TIME) is an rvalue for the microseconds component of TIME.
  50         This returns zero if EMACS_TIME doesn't have a microseconds component.
  51    EMACS_SET_USECS (TIME, MICROSECONDS) sets that to MICROSECONDS.
  52         This does nothing if EMACS_TIME doesn't have a microseconds component.
  53
  54    EMACS_SET_SECS_USECS (TIME, SECS, USECS) sets both components of TIME.
  55
  56    EMACS_GET_TIME (TIME) stores the current system time in TIME, which
  57         should be an lvalue.
  58    EMACS_SET_UTIMES (PATH, ATIME, MTIME) changes the last-access and
  59         last-modification times of the file named PATH to ATIME and
  60         MTIME, which are EMACS_TIMEs.
  61
  62    EMACS_ADD_TIME (DEST, SRC1, SRC2) adds SRC1 to SRC2 and stores the
  63         result in DEST.  SRC should not be negative.
  64
  65    EMACS_SUB_TIME (DEST, SRC1, SRC2) subtracts SRC2 from SRC1 and
  66         stores the result in DEST.  SRC should not be negative.
  67    EMACS_TIME_NEG_P (TIME) is true iff TIME is negative.
  68
  69 */
  70
  71 #ifdef HAVE_TIMEVAL
  72
  73 #define EMACS_HAS_USECS
  74
  75 #define EMACS_TIME struct timeval
  76 #define EMACS_SECS(time)                    ((time).tv_sec  + 0)
  77 #define EMACS_USECS(time)                   ((time).tv_usec + 0)
  78 #define EMACS_SET_SECS(time, seconds)       ((time).tv_sec  = (seconds))
  79 #define EMACS_SET_USECS(time, microseconds) ((time).tv_usec = (microseconds))
  80
  81 #define EMACS_GET_TIME(time)                                    \
  82 {                                                               \
  83   struct timezone dummy;                                        \
  84   gettimeofday (&(time), &dummy);                               \
  85 }
  86
  87 #define EMACS_ADD_TIME(dest, src1, src2)                        \
  88 {                                                               \
  89   (dest).tv_sec  = (src1).tv_sec  + (src2).tv_sec;              \
  90   (dest).tv_usec = (src1).tv_usec + (src2).tv_usec;             \
  91   if ((dest).tv_usec > 1000000)                                 \
  92     (dest).tv_usec -= 1000000, (dest).tv_sec++;                 \
  93 }
  94
  95 #define EMACS_SUB_TIME(dest, src1, src2)                        \
  96 {                                                               \
  97   (dest).tv_sec  = (src1).tv_sec  - (src2).tv_sec;              \
  98   (dest).tv_usec = (src1).tv_usec - (src2).tv_usec;             \
  99   if ((dest).tv_usec < 0)                                       \
 100     (dest).tv_usec += 1000000, (dest).tv_sec--;                 \
 101 }
 102
 103 #define EMACS_TIME_NEG_P(time)                                  \
 104   ((time).tv_sec < 0                                            \
 105    || ((time).tv_sec == 0                                       \
 106        && (time).tv_usec < 0))
 107
 108 #else /* ! defined (HAVE_TIMEVAL) */
 109
 110 #define EMACS_TIME int
 111 #define EMACS_SECS(time)                    (time)
 112 #define EMACS_USECS(time)                   0
 113 #define EMACS_SET_SECS(time, seconds)       ((time) = (seconds))
 114 #define EMACS_SET_USECS(time, usecs)        0
 115
 116 #define EMACS_GET_TIME(t) ((t) = time ((long *) 0))
 117 #define EMACS_ADD_TIME(dest, src1, src2) ((dest) = (src1) + (src2))
 118 #define EMACS_SUB_TIME(dest, src1, src2) ((dest) = (src1) - (src2))
 119 #define EMACS_TIME_NEG_P(t) ((t) < 0)
 120
 121 #endif /* ! defined (HAVE_TIMEVAL) */
 122
 123 #define EMACS_SET_SECS_USECS(time, secs, usecs)                 \
 124   (EMACS_SET_SECS (time, secs), EMACS_SET_USECS (time, usecs))
 125
 126 #ifdef USE_UTIME
 127
 128 #define EMACS_SET_UTIMES(path, atime, mtime)                    \
 129   {                                                             \
 130     time_t tv[2];                                               \
 131     tv[0] = EMACS_SECS (atime);                                 \
 132     tv[1] = EMACS_SECS (mtime);                                 \
 133     utime ((path), tv);                                         \
 134   }
 135
 136 #else /* ! defined (USE_UTIME) */
 137
 138 #define EMACS_SET_UTIMES(path, atime, mtime)                    \
 139   {                                                             \
 140     EMACS_TIME tv[2];                                           \
 141     tv[0] = atime;                                              \
 142     tv[1] = mtime;                                              \
 143     utimes ((path), tv);                                        \
 144   }
 145
 146 #endif /* ! defined (USE_UTIME) */
 147
 148 \f
 149
 150 /* EMACS_CURRENT_TIME_ZONE (int *OFFSET, int *SAVINGS_FLAG,
 151                             char *STANDARD_ABBR, char *SAVINGS_ABBR);
 152    expands to a statement which stores information about the current
 153    time zone in its arguments.
 154
 155    *OFFSET is set to the number of minutes EAST of Greenwich at which
 156    the site's time zone is located.  This should describe the offset
 157    to standard time only; if some sort of daylight savings time is in
 158    effect, that should not affect this value.  Note that the tm_gmtoff
 159    member of the struct tm returned by localtime is adjusted for
 160    daylight savings, so you don't want to use localtime to set
 161    *OFFSET; gettimeofday does the right thing.
 162
 163    *SAVINGS_FLAG is set to 1 if some sort of daylight savings time is
 164    currently in effect, or 0 if no seasonal adjustment is currently
 165    active.
 166
 167    *STANDARD_ABBR points to an array of at least 10 characters, which
 168    should be set to the standard abbreviation for the time zone name
 169    when daylight savings time is not active.  For example, EDT would
 170    be appropriate for the Eastern time zone of the USA.
 171
 172    *SAVINGS_ABBR points to an array of at least 10 characters, which
 173    should be set to the standard abbreviation for the time zone name
 174    when daylight savings time is active.  For example, EST would be
 175    appropriate for the Eastern time zone of the USA.
 176
 177    If the operating system cannot provide all this information, then
 178    this macro will not be defined.  */
 179
 180
 181 /* The operating system configuration file can define
 182    EMACS_CURRENT_TIME_ZONE.   If not, we'll take a shot at it here.  */
 183
 184 #ifndef EMACS_CURRENT_TIME_ZONE
 185
 186 /* System V derivatives have a timezone global variable.  */
 187 #if defined(USG) || defined(VMS)
 188 #define EMACS_GET_TZ_OFFSET(offset)                                     \
 189   do {                                                                  \
 190     tzset ();                                                           \
 191     *(offset) = timezone;                                               \
 192   } while (0)
 193 #endif
 194
 195 /* If we have timeval, then we have gettimeofday; that's half the battle.  */
 196 #if defined (HAVE_TIMEVAL) && !defined (EMACS_GET_TZ_OFFSET)
 197 #define EMACS_GET_TZ_OFFSET(offset)                                     \
 198   do {                                                                  \
 199     struct timeval dummy;                                               \
 200     struct timezone zoneinfo;                                           \
 201                                                                         \
 202     gettimeofday (&dummy, &zoneinfo);                                   \
 203     *(offset) = -zoneinfo.tz_minuteswest;                               \
 204   } while (0)
 205 #endif /* ! defined (HAVE_TIMEVAL) */
 206
 207 /* The following sane systems have a tzname array.  The timezone function
 208    is a stupid idea; timezone names can only be determined geographically,
 209    not by Greenwich offset.  */
 210 #if defined (ultrix) || defined (hpux) || defined (_AIX) || defined (USG) || defined(VMS)
 211
 212 #define EMACS_GET_TZ_NAMES(standard, savings)                           \
 213   do {                                                                  \
 214     extern char *tzname[2];                                             \
 215     strcpy ((standard), tzname[0]);                                     \
 216     strcpy ((savings), tzname[1]);                                      \
 217   } while (0)
 218
 219 #else /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
 220 /* If we are running SunOS, Mt. Xinu BSD, or MACH 2.5, these systems have a
 221    timezone function.  */
 222 #if (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun) || defined (NeXT)
 223
 224 #define EMACS_GET_TZ_NAMES(standard, savings)                           \
 225   do {                                                                  \
 226     struct timeval dummy;                                               \
 227     struct timezone zoneinfo;                                           \
 228     extern char *timezone ();                                           \
 229                                                                         \
 230     gettimeofday (&dummy, &zoneinfo);                                   \
 231     strcpy ((standard), timezone (zoneinfo.tz_minuteswest, 0));         \
 232     strcpy ((savings),  timezone (zoneinfo.tz_minuteswest, 1));         \
 233   } while (0)
 234
 235 #endif /* ! (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun) */
 236 #endif /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
 237
 238 /* If we can get all the information we need, let's define the macro!  */
 239 #if defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES)
 240
 241 #define EMACS_CURRENT_TIME_ZONE(offset, savings_flag, standard, savings)\
 242   do {                                                                  \
 243     EMACS_TIME t;                                                       \
 244     long secs;                                                          \
 245     struct tm *tmp;                                                     \
 246                                                                         \
 247     EMACS_GET_TIME (t);                                                 \
 248     secs = EMACS_SECS (t);                                              \
 249     tmp = localtime (&secs);                                            \
 250     *(savings_flag) = tmp->tm_isdst;                                    \
 251                                                                         \
 252     EMACS_GET_TZ_OFFSET (offset);                                       \
 253     EMACS_GET_TZ_NAMES (standard, savings);                             \
 254   } while (0)
 255 #endif /* ! defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES) */
 256
 257 #endif /* EMACS_CURRENT_TIME_ZONE */