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