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