sysdeps/posix/gettimeofday.c

   1 /* Copyright (C) 1991, 92, 94, 95, 96 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, 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
  30 /* Get the current time of day and timezone information,
  31    putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
  32    Returns 0 on success, -1 on errors.  */
  33 int
  34 __gettimeofday (tv, tz)
  35      struct timeval *tv;
  36      struct timezone *tz;
  37 {
  38   if (tv == NULL)
  39     {
  40       errno = EINVAL;
  41       return -1;
  42     }
  43
  44   tv->tv_sec = (long int) time ((time_t *) NULL);
  45   tv->tv_usec = 0L;
  46
  47   if (tz != NULL)
  48     {
  49       const time_t timer = tv->tv_sec;
  50       struct tm tm;
  51       const struct tm *tmp;
  52
  53       const long int save_timezone = __timezone;
  54       const long int save_daylight = __daylight;
  55       char *save_tzname[2];
  56       save_tzname[0] = __tzname[0];
  57       save_tzname[1] = __tzname[1];
  58
  59       tmp = localtime_r (&timer, &tm);
  60
  61       tz->tz_minuteswest = __timezone / 60;
  62       tz->tz_dsttime = __daylight;
  63
  64       __timezone = save_timezone;
  65       __daylight = save_daylight;
  66       __tzname[0] = save_tzname[0];
  67       __tzname[1] = save_tzname[1];
  68
  69       if (tmp == NULL)
  70         return -1;
  71     }
  72
  73   return 0;
  74 }
  75
  76 weak_alias (__gettimeofday, gettimeofday)