time/localtime.c

   1 /* Convert `time_t' to `struct tm' in local time zone.
   2    Copyright (C) 1991-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <time.h>
  20
  21 /* C89 says that localtime and gmtime return the same pointer.
  22    Although C99 and later relax this to let localtime and gmtime
  23    return different pointers, POSIX and glibc currently follow C89's stricter
  24    requirement even though this can cause naive programs to misbehave.  */
  25 struct tm _tmbuf;
  26
  27
  28 /* Return the `struct tm' representation of *T in local time,
  29    using *TP to store the result.  */
  30 struct tm *
  31 __localtime64_r (const __time64_t *t, struct tm *tp)
  32 {
  33   return __tz_convert (*t, 1, tp);
  34 }
  35
  36 /* Provide a 32-bit variant if needed.  */
  37
  38 #if __TIMESIZE != 64
  39
  40 struct tm *
  41 __localtime_r (const time_t *t, struct tm *tp)
  42 {
  43   __time64_t t64 = *t;
  44   return __localtime64_r (&t64, tp);
  45 }
  46 libc_hidden_def (__localtime64_r)
  47
  48 #endif
  49
  50 weak_alias (__localtime_r, localtime_r)
  51
  52
  53 /* Return the `struct tm' representation of *T in local time.  */
  54 struct tm *
  55 __localtime64 (const __time64_t *t)
  56 {
  57   return __tz_convert (*t, 1, &_tmbuf);
  58 }
  59 libc_hidden_def (__localtime64)
  60
  61 /* Provide a 32-bit variant if needed.  */
  62
  63 #if __TIMESIZE != 64
  64
  65 struct tm *
  66 localtime (const time_t *t)
  67 {
  68   __time64_t t64 = *t;
  69   return __localtime64 (&t64);
  70 }
  71 libc_hidden_def (localtime)
  72
  73 #endif