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