lib/localtime-buffer.c

   1 /* Provide access to the last buffer returned by localtime() or gmtime().
   2
   3    Copyright (C) 2001-2003, 2005-2007, 2009-2019 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program 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 General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* written by Jim Meyering */
  19
  20 #include <config.h>
  21
  22 /* Specification.  */
  23 #include "localtime-buffer.h"
  24
  25 #if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
  26
  27 static struct tm tm_zero_buffer;
  28 struct tm *localtime_buffer_addr = &tm_zero_buffer;
  29
  30 /* This is a wrapper for localtime.
  31
  32    On the first call, record the address of the static buffer that
  33    localtime uses for its result.  */
  34
  35 struct tm *
  36 rpl_localtime (time_t const *timep)
  37 #undef localtime
  38 {
  39   struct tm *tm = localtime (timep);
  40
  41   if (localtime_buffer_addr == &tm_zero_buffer)
  42     localtime_buffer_addr = tm;
  43
  44   return tm;
  45 }
  46
  47 /* Same as above, since gmtime and localtime use the same buffer.  */
  48 struct tm *
  49 rpl_gmtime (time_t const *timep)
  50 #undef gmtime
  51 {
  52   struct tm *tm = gmtime (timep);
  53
  54   if (localtime_buffer_addr == &tm_zero_buffer)
  55     localtime_buffer_addr = tm;
  56
  57   return tm;
  58 }
  59
  60 #endif