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 /* SVr4 doesn't actually declare this in its #include files.  */
  44 #ifdef USG5_4
  45 extern long timezone;
  46 #endif
  47
  48 \f
  49 /* EMACS_TIME is the type to use to represent temporal intervals -
  50    struct timeval on some systems, int on others.  It can be passed as
  51    the timeout argument to the select () system call.
  52
  53    EMACS_SECS (TIME) is an rvalue for the seconds component of TIME.
  54    EMACS_SET_SECS (TIME, SECONDS) sets that to SECONDS.
  55
  56    EMACS_HAS_USECS is defined iff EMACS_TIME has a usecs component.
  57    EMACS_USECS (TIME) is an rvalue for the milliseconds component of TIME.
  58         This returns zero if EMACS_TIME doesn't have a milliseconds component.
  59    EMACS_SET_USECS (TIME, MILLISECONDS) sets that to MILLISECONDS.
  60         This does nothing if EMACS_TIME doesn't have a milliseconds component.
  61
  62    EMACS_SET_SECS_USECS (TIME, SECS, USECS) sets both components of TIME.
  63
  64    EMACS_GET_TIME (TIME) stores the current system time in TIME, which
  65         should be an lvalue.
  66    EMACS_SET_UTIMES (PATH, ATIME, MTIME) changes the last-access and
  67         last-modification times of the file named PATH to ATIME and
  68         MTIME, which are EMACS_TIMEs.
  69
  70    EMACS_ADD_TIME (DEST, SRC1, SRC2) adds SRC1 to SRC2 and stores the
  71         result in DEST.  SRC should not be negative.
  72
  73    EMACS_SUB_TIME (DEST, SRC1, SRC2) subtracts SRC2 from SRC1 and
  74         stores the result in DEST.  SRC should not be negative.
  75    EMACS_TIME_NEG_P (TIME) is true iff TIME is negative.
  76
  77 */
  78
  79 #ifdef HAVE_TIMEVAL
  80
  81 #define EMACS_TIME struct timeval
  82 #define EMACS_SECS(time)                    ((time).tv_sec  + 0)
  83 #define EMACS_USECS(time)                   ((time).tv_usec + 0)
  84 #define EMACS_SET_SECS(time, seconds)       ((time).tv_sec  = (seconds))
  85 #define EMACS_SET_USECS(time, milliseconds) ((time).tv_usec = (milliseconds))
  86
  87 #define EMACS_GET_TIME(time)                                    \
  88 {                                                               \
  89   struct timezone dummy;                                        \
  90   gettimeofday (&(time), &dummy);                               \
  91 }
  92
  93 #define EMACS_ADD_TIME(dest, src1, src2)                        \
  94 {                                                               \
  95   (dest).tv_sec  = (src1).tv_sec  + (src2).tv_sec;              \
  96   (dest).tv_usec = (src1).tv_usec + (src2).tv_usec;             \
  97   if ((dest).tv_usec > 1000000)                                 \
  98     (dest).tv_usec -= 1000000, (dest).tv_sec++;                 \
  99 }
 100
 101 #define EMACS_SUB_TIME(dest, src1, src2)                        \
 102 {                                                               \
 103   (dest).tv_sec  = (src1).tv_sec  - (src2).tv_sec;              \
 104   (dest).tv_usec = (src1).tv_usec - (src2).tv_usec;             \
 105   if ((dest).tv_usec < 0)                                       \
 106     (dest).tv_usec += 1000000, (dest).tv_sec--;                 \
 107 }
 108
 109 #define EMACS_TIME_NEG_P(time)                                  \
 110   ((time).tv_sec < 0                                            \
 111    || ((time).tv_sec == 0                                       \
 112        && (time).tv_usec < 0))
 113
 114 #else /* ! defined (HAVE_TIMEVAL) */
 115
 116 #define EMACS_TIME int
 117 #define EMACS_SECS(time)                    (time)
 118 #define EMACS_USECS(time)                   0
 119 #define EMACS_SET_SECS(time, seconds)       ((time) = (seconds))
 120 #define EMACS_SET_USECS(time, usecs)        0
 121
 122 #define EMACS_GET_TIME(t) ((t) = time ((long *) 0))
 123 #define EMACS_ADD_TIME(dest, src1, src2) ((dest) = (src1) + (src2))
 124 #define EMACS_SUB_TIME(dest, src1, src2) ((dest) = (src1) - (src2))
 125 #define EMACS_TIME_NEG_P(t) ((t) < 0)
 126
 127 #endif /* ! defined (HAVE_TIMEVAL) */
 128
 129 #define EMACS_SET_SECS_USECS(time, secs, usecs)                 \
 130   (EMACS_SET_SECS (time, secs), EMACS_SET_USECS (time, usecs))
 131
 132 #ifdef USE_UTIME
 133
 134 #define EMACS_SET_UTIMES(path, atime, mtime)                    \
 135   {                                                             \
 136     time_t tv[2];                                               \
 137     tv[0] = EMACS_SECS (atime);                                 \
 138     tv[1] = EMACS_SECS (mtime);                                 \
 139     utime ((path), tv);                                         \
 140   }
 141
 142 #else /* ! defined (USE_UTIME) */
 143
 144 #define EMACS_SET_UTIMES(path, atime, mtime)                    \
 145   {                                                             \
 146     EMACS_TIME tv[2];                                           \
 147     tv[0] = atime;                                              \
 148     tv[1] = mtime;                                              \
 149     utimes ((path), tv);                                        \
 150   }
 151
 152 #endif /* ! defined (USE_UTIME) */
 153
 154 \f
 155
 156 /* EMACS_CURRENT_TIME_ZONE (int *OFFSET, int *SAVINGS_FLAG,
 157                             char *STANDARD_ABBR, char *SAVINGS_ABBR);
 158    expands to a statement which stores information about the current
 159    time zone in its arguments.
 160
 161    *OFFSET is set to the number of minutes EAST of Greenwich at which
 162    the site's time zone is located.  This should describe the offset
 163    to standard time only; if some sort of daylight savings time is in
 164    effect, that should not affect this value.  Note that the tm_gmtoff
 165    member of the struct tm returned by localtime is adjusted for
 166    daylight savings, so you don't want to use localtime to set
 167    *OFFSET; gettimeofday does the right thing.
 168
 169    *SAVINGS_FLAG is set to 1 if some sort of daylight savings time is
 170    currently in effect, or 0 if no seasonal adjustment is currently
 171    active.
 172
 173    *STANDARD_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 not active.  For example, EDT would
 176    be appropriate for the Eastern time zone of the USA.
 177
 178    *SAVINGS_ABBR points to an array of at least 10 characters, which
 179    should be set to the standard abbreviation for the time zone name
 180    when daylight savings time is active.  For example, EST would be
 181    appropriate for the Eastern time zone of the USA.
 182
 183    If the operating system cannot provide all this information, then
 184    this macro will not be defined.  */
 185
 186
 187 /* The operating system configuration file can define
 188    EMACS_CURRENT_TIME_ZONE.   If not, we'll take a shot at it here.  */
 189
 190 #ifndef EMACS_CURRENT_TIME_ZONE
 191
 192 /* System V derivatives have a timezone global variable.  */
 193 #ifdef USG
 194 #define EMACS_GET_TZ_OFFSET(offset)                                     \
 195   do {                                                                  \
 196     tzset ();                                                           \
 197     *(offset) = timezone;                                               \
 198   } while (0)
 199 #endif
 200
 201 /* If we have timeval, then we have gettimeofday; that's half the battle.  */
 202 #if defined (HAVE_TIMEVAL) && !defined (EMACS_GET_TZ_OFFSET)
 203 #define EMACS_GET_TZ_OFFSET(offset)                                     \
 204   do {                                                                  \
 205     struct timeval dummy;                                               \
 206     struct timezone zoneinfo;                                           \
 207                                                                         \
 208     gettimeofday (&dummy, &zoneinfo);                                   \
 209     *(offset) = -zoneinfo.tz_minuteswest;                               \
 210   } while (0)
 211 #endif /* ! defined (HAVE_TIMEVAL) */
 212
 213 /* The following sane systems have a tzname array.  The timezone() function
 214    is a stupid idea; timezone names can only be determined geographically,
 215    not by Greenwich offset.  */
 216 #if defined (ultrix) || defined (hpux) || defined (_AIX) || defined (USG)
 217
 218 #define EMACS_GET_TZ_NAMES(standard, savings)                           \
 219   do {                                                                  \
 220     extern char *tzname[2];                                             \
 221     strcpy ((standard), tzname[0]);                                     \
 222     strcpy ((savings), tzname[1]);                                      \
 223   } while (0)
 224
 225 #else /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
 226 /* If we are running SunOS, Mt. Xinu BSD, or MACH 2.5, these systems have a
 227    timezone() function.  */
 228 #if (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun)
 229
 230 #define EMACS_GET_TZ_NAMES(standard, savings)                           \
 231   do {                                                                  \
 232     struct timeval dummy;                                               \
 233     struct timezone zoneinfo;                                           \
 234     extern char *timezone ();                                           \
 235                                                                         \
 236     gettimeofday (&dummy, &zoneinfo);                                   \
 237     strcpy ((standard), timezone (zoneinfo.tz_minuteswest, 0));         \
 238     strcpy ((savings),  timezone (zoneinfo.tz_minuteswest, 1));         \
 239   } while (0)
 240
 241 #endif /* ! (defined (hp9000) && ! defined (hpux) && defined (unix)) || defined (MACH) || defined (sun) */
 242 #endif /* ! defined (ultrix) || defined (hpux) || defined (_AIX) */
 243
 244 /* If we can get all the information we need, let's define the macro!  */
 245 #if defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES)
 246
 247 #define EMACS_CURRENT_TIME_ZONE(offset, savings_flag, standard, savings)\
 248   do {                                                                  \
 249     EMACS_TIME t;                                                       \
 250     long secs;                                                          \
 251     struct tm *tmp;                                                     \
 252                                                                         \
 253     EMACS_GET_TIME (t);                                                 \
 254     secs = EMACS_SECS (t);                                              \
 255     tmp = localtime (&secs);                                            \
 256     *(savings_flag) = tmp->tm_isdst;                                    \
 257                                                                         \
 258     EMACS_GET_TZ_OFFSET (offset);                                       \
 259     EMACS_GET_TZ_NAMES (standard, savings);                             \
 260   } while (0)
 261 #endif /* ! defined (EMACS_GET_TZ_OFFSET) && defined (EMACS_GET_TZ_NAMES) */
 262
 263 #endif /* EMACS_CURRENT_TIME_ZONE */