lib/timegm.c

   1 /* Convert UTC calendar time to simple time.  Like mktime but assumes UTC.
   2
   3    Copyright (C) 1994, 1997, 2003-2004, 2006-2007, 2009-2017 Free Software
   4    Foundation, Inc.  This file is part of the GNU C Library.
   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 3, 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, see <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _LIBC
  20 # include <config.h>
  21 #endif
  22
  23 #include <time.h>
  24
  25 #ifdef _LIBC
  26 typedef time_t mktime_offset_t;
  27 #else
  28 # undef __gmtime_r
  29 # define __gmtime_r gmtime_r
  30 # define __mktime_internal mktime_internal
  31 # include "mktime-internal.h"
  32 #endif
  33
  34 time_t
  35 timegm (struct tm *tmp)
  36 {
  37   static mktime_offset_t gmtime_offset;
  38   tmp->tm_isdst = 0;
  39   return __mktime_internal (tmp, __gmtime_r, &gmtime_offset);
  40 }