sysdeps/posix/gettimeofday.c

   1 /* Copyright (C) 1991, 92, 94, 95, 96, 97, 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <sys/time.h>
  22
  23 #ifndef HAVE_GNU_LD
  24 #define __daylight      daylight
  25 #define __timezone      timezone
  26 #define __tzname        tzname
  27 #endif
  28
  29 #undef __gettimeofday
  30
  31 /* Get the current time of day and timezone information,
  32    putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
  33    Returns 0 on success, -1 on errors.  */
  34 int
  35 __gettimeofday (tv, tz)
  36      struct timeval *tv;
  37      struct timezone *tz;
  38 {
  39   if (tv == NULL)
  40     {
  41       __set_errno (EINVAL);
  42       return -1;
  43     }
  44
  45   tv->tv_sec = (long int) time ((time_t *) NULL);
  46   tv->tv_usec = 0L;
  47
  48   if (tz != NULL)
  49     {
  50       const time_t timer = tv->tv_sec;
  51       struct tm tm;
  52       const struct tm *tmp;
  53
  54       const long int save_timezone = __timezone;
  55       const long int save_daylight = __daylight;
  56       char *save_tzname[2];
  57       save_tzname[0] = __tzname[0];
  58       save_tzname[1] = __tzname[1];
  59
  60       tmp = localtime_r (&timer, &tm);
  61
  62       tz->tz_minuteswest = __timezone / 60;
  63       tz->tz_dsttime = __daylight;
  64
  65       __timezone = save_timezone;
  66       __daylight = save_daylight;
  67       __tzname[0] = save_tzname[0];
  68       __tzname[1] = save_tzname[1];
  69
  70       if (tmp == NULL)
  71         return -1;
  72     }
  73
  74   return 0;
  75 }
  76
  77 INTDEF(__gettimeofday)
  78 weak_alias (__gettimeofday, gettimeofday)