lib/time_r.c

   1 /* Reentrant time functions like localtime_r.
   2
   3    Copyright (C) 2003, 2006-2007, 2010-2024 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #include <config.h>
  21
  22 #include <time.h>
  23
  24 /* The replacement functions in this file are only used on native Windows.
  25    They are multithread-safe, because the gmtime() and localtime() functions
  26    on native Windows — both in the ucrt and in the older MSVCRT — return a
  27    pointer to a 'struct tm' in thread-local memory.  */
  28
  29 static struct tm *
  30 copy_tm_result (struct tm *dest, struct tm const *src)
  31 {
  32   if (! src)
  33     return 0;
  34   *dest = *src;
  35   return dest;
  36 }
  37
  38
  39 struct tm *
  40 gmtime_r (time_t const * restrict t, struct tm * restrict tp)
  41 {
  42   return copy_tm_result (tp, gmtime (t));
  43 }
  44
  45 struct tm *
  46 localtime_r (time_t const * restrict t, struct tm * restrict tp)
  47 {
  48   return copy_tm_result (tp, localtime (t));
  49 }