sysdeps/posix/gettimeofday.c

   1 /* Copyright (C) 1991,1992,1994-1997,2002,2005 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <time.h>
  20 #include <sys/time.h>
  21
  22 #undef __gettimeofday
  23
  24 /* Get the current time of day and timezone information,
  25    putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
  26    Returns 0 on success, -1 on errors.  */
  27 int
  28 __gettimeofday (tv, tz)
  29      struct timeval *tv;
  30      struct timezone *tz;
  31 {
  32   if (tv == NULL)
  33     {
  34       __set_errno (EINVAL);
  35       return -1;
  36     }
  37
  38   tv->tv_sec = (long int) time ((time_t *) NULL);
  39   tv->tv_usec = 0L;
  40
  41   if (tz != NULL)
  42     {
  43       const time_t timer = tv->tv_sec;
  44       struct tm tm;
  45       const struct tm *tmp;
  46
  47       const long int save_timezone = __timezone;
  48       const long int save_daylight = __daylight;
  49       char *save_tzname[2];
  50       save_tzname[0] = __tzname[0];
  51       save_tzname[1] = __tzname[1];
  52
  53       tmp = localtime_r (&timer, &tm);
  54
  55       tz->tz_minuteswest = __timezone / 60;
  56       tz->tz_dsttime = __daylight;
  57
  58       __timezone = save_timezone;
  59       __daylight = save_daylight;
  60       __tzname[0] = save_tzname[0];
  61       __tzname[1] = save_tzname[1];
  62
  63       if (tmp == NULL)
  64         return -1;
  65     }
  66
  67   return 0;
  68 }
  69
  70 INTDEF(__gettimeofday)
  71 weak_alias (__gettimeofday, gettimeofday)