external/gpl2/xcvs/dist/lib/gettimeofday.c

   1 /* Work around the bug in some systems whereby gettimeofday clobbers the
   2    static buffer that localtime uses for it's return value.  The gettimeofday
   3    function from Mac OS X 10.0.4, i.e. Darwin 1.3.7 has this problem.
   4    The tzset replacement is necessary for at least Solaris 2.5, 2.5.1, and 2.6.
   5    Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software Foundation,
  19    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  20
  21 /* written by Jim Meyering */
  22
  23 #ifdef HAVE_CONFIG_H
  24 # include <config.h>
  25 #endif
  26
  27 /* Disable the definitions of these functions (from config.h)
  28    so we can use the library versions here.  */
  29 #undef gettimeofday
  30 #undef gmtime
  31 #undef localtime
  32 #undef tzset
  33
  34 #include <sys/types.h>
  35
  36 #if TIME_WITH_SYS_TIME
  37 # include <sys/time.h>
  38 # include <time.h>
  39 #else
  40 # if HAVE_SYS_TIME_H
  41 #  include <sys/time.h>
  42 # else
  43 #  include <time.h>
  44 # endif
  45 #endif
  46
  47 #include <stdlib.h>
  48
  49 static struct tm *localtime_buffer_addr;
  50
  51 /* This is a wrapper for localtime.  It is used only on systems for which
  52    gettimeofday clobbers the static buffer used for localtime's result.
  53
  54    On the first call, record the address of the static buffer that
  55    localtime uses for its result.  */
  56
  57 struct tm *
  58 rpl_localtime (const time_t *timep)
  59 {
  60   struct tm *tm = localtime (timep);
  61
  62   if (! localtime_buffer_addr)
  63     localtime_buffer_addr = tm;
  64
  65   return tm;
  66 }
  67
  68 /* Same as above, since gmtime and localtime use the same buffer.  */
  69 struct tm *
  70 rpl_gmtime (const time_t *timep)
  71 {
  72   struct tm *tm = gmtime (timep);
  73
  74   if (! localtime_buffer_addr)
  75     localtime_buffer_addr = tm;
  76
  77   return tm;
  78 }
  79
  80 /* This is a wrapper for gettimeofday.  It is used only on systems for which
  81    gettimeofday clobbers the static buffer used for localtime's result.
  82
  83    Save and restore the contents of the buffer used for localtime's result
  84    around the call to gettimeofday.  */
  85
  86 int
  87 rpl_gettimeofday (struct timeval *tv, struct timezone *tz)
  88 {
  89   struct tm save;
  90   int result;
  91
  92   if (! localtime_buffer_addr)
  93     {
  94       time_t t = 0;
  95       localtime_buffer_addr = localtime (&t);
  96     }
  97
  98   save = *localtime_buffer_addr;
  99   result = gettimeofday (tv, tz);
 100   *localtime_buffer_addr = save;
 101
 102   return result;
 103 }
 104
 105 /* This is a wrapper for tzset. It is used only on systems for which
 106    tzset may clobber the static buffer used for localtime's result.
 107    Save and restore the contents of the buffer used for localtime's
 108    result around the call to tzset.  */
 109 void
 110 rpl_tzset (void)
 111 {
 112   struct tm save;
 113
 114   if (! localtime_buffer_addr)
 115     {
 116       time_t t = 0;
 117       localtime_buffer_addr = localtime (&t);
 118     }
 119
 120   save = *localtime_buffer_addr;
 121   tzset ();
 122   *localtime_buffer_addr = save;
 123 }