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