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    Copyright (C) 2001 Free Software Foundation, Inc.
   5
   6    This program 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 2, or (at your option)
   9    any later version.
  10
  11    This program 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 this program; if not, write to the Free Software Foundation,
  18    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* written by Jim Meyering */
  21
  22 #include <config.h>
  23
  24 /* Disable the definition of gettimeofday (from config.h) so we can use
  25    the library version.  */
  26 #undef gettimeofday
  27
  28 #include <sys/types.h>
  29
  30 #if TIME_WITH_SYS_TIME
  31 # include <sys/time.h>
  32 # include <time.h>
  33 #else
  34 # if HAVE_SYS_TIME_H
  35 #  include <sys/time.h>
  36 # else
  37 #  include <time.h>
  38 # endif
  39 #endif
  40
  41 #include <stdlib.h>
  42
  43 static struct tm *localtime_buffer_addr;
  44
  45 /* This is a wrapper for gettimeofday.  It is used only on systems for which
  46    gettimeofday clobbers the static buffer used for localtime's result.
  47
  48    Save and restore the contents of the buffer used for localtime's result
  49    around the call to gettimeofday.  */
  50
  51 int
  52 rpl_gettimeofday (struct timeval *tv, struct timezone *tz)
  53 {
  54   struct tm save;
  55   int result;
  56
  57   if (! localtime_buffer_addr)
  58     {
  59       time_t t = 0;
  60       localtime_buffer_addr = localtime (&t);
  61     }
  62
  63   save = *localtime_buffer_addr;
  64   result = gettimeofday (tv, tz);
  65   *localtime_buffer_addr = save;
  66
  67   return result;
  68 }