1  /* Test for ctime
       2     Copyright (C) 2021-2023 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  #include <stdlib.h>
      21  #include <support/check.h>
      22  
      23  static int
      24  do_test (void)
      25  {
      26    char *str;
      27    char strb[32];
      28    time_t t;
      29  
      30    /* Use glibc time zone extension "TZ=:" to to guarantee that UTC
      31       without leap seconds is used for the test.  */
      32    TEST_VERIFY_EXIT (setenv ("TZ", ":", 1) == 0);
      33    tzset ();
      34  
      35    /* Check if the epoch time can be converted.  */
      36    t = 0;
      37    str = ctime (&t);
      38    TEST_COMPARE_STRING (str, "Thu Jan  1 00:00:00 1970\n");
      39  
      40    /* Same as before but with ctime_r.  */
      41    str = ctime_r (&t, strb);
      42    TEST_VERIFY (str == strb);
      43    TEST_COMPARE_STRING (str, "Thu Jan  1 00:00:00 1970\n");
      44  
      45    /* Check if the max time value for 32 bit time_t can be converted.  */
      46    t = 0x7fffffff;
      47    str = ctime (&t);
      48    TEST_COMPARE_STRING (str, "Tue Jan 19 03:14:07 2038\n");
      49  
      50    /* Same as before but with ctime_r.  */
      51    str = ctime_r (&t, strb);
      52    TEST_VERIFY (str == strb);
      53    TEST_COMPARE_STRING (str, "Tue Jan 19 03:14:07 2038\n");
      54  
      55    /* Check if we run on port with 32 bit time_t size */
      56    time_t tov;
      57    if (__builtin_add_overflow (t, 1, &tov))
      58      return 0;
      59  
      60    /* Check if the time is converted after 32 bit time_t overflow.  */
      61    str = ctime (&tov);
      62    TEST_COMPARE_STRING (str, "Tue Jan 19 03:14:08 2038\n");
      63  
      64    /* Same as before but with ctime_r.  */
      65    str = ctime_r (&tov, strb);
      66    TEST_VERIFY (str == strb);
      67    TEST_COMPARE_STRING (str, "Tue Jan 19 03:14:08 2038\n");
      68  
      69    return 0;
      70  }
      71  
      72  #include <support/test-driver.c>