tests/test-gettimeofday.c

   1 /*
   2  * Copyright (C) 2005, 2007, 2009-2024 Free Software Foundation, Inc.
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Jim Meyering and Bruno Haible.  */
  18
  19 #include <config.h>
  20
  21 #include <sys/time.h>
  22
  23 #include "signature.h"
  24 SIGNATURE_CHECK (gettimeofday, int,
  25                  (struct timeval *, GETTIMEOFDAY_TIMEZONE *));
  26
  27 #include <time.h>
  28
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "macros.h"
  34
  35 static void
  36 test_clobber ()
  37 {
  38   time_t t = 0;
  39   struct tm *lt;
  40   struct tm saved_lt;
  41   struct timeval tv;
  42   lt = localtime (&t);
  43   saved_lt = *lt;
  44   gettimeofday (&tv, NULL);
  45   if (memcmp (lt, &saved_lt, sizeof (struct tm)) != 0)
  46     {
  47       fprintf (stderr, "gettimeofday still clobbers the localtime buffer!\n");
  48       exit (1);
  49     }
  50 }
  51
  52 static void
  53 test_consistency ()
  54 {
  55   struct timeval tv1;
  56   time_t tt2;
  57   struct timeval tv3;
  58   time_t tt4;
  59
  60   ASSERT (gettimeofday (&tv1, NULL) == 0);
  61   tt2 = time (NULL);
  62   ASSERT (gettimeofday (&tv3, NULL) == 0);
  63   tt4 = time (NULL);
  64
  65   /* Verify monotonicity of gettimeofday().  */
  66   ASSERT (tv1.tv_sec < tv3.tv_sec
  67           || (tv1.tv_sec == tv3.tv_sec && tv1.tv_usec <= tv3.tv_usec));
  68
  69   /* Verify monotonicity of time().  */
  70   ASSERT (tt2 <= tt4);
  71
  72   /* Verify that the tv_sec field of the result is the same as time(NULL).  */
  73   /* Note: It's here that the dependency to the 'time' module is needed.
  74      Without it, this assertion would sometimes fail on glibc systems, see
  75      https://sourceware.org/bugzilla/show_bug.cgi?id=30200  */
  76   ASSERT (tv1.tv_sec <= tt2);
  77   ASSERT (tt2 <= tv3.tv_sec);
  78   ASSERT (tv3.tv_sec <= tt4);
  79 }
  80
  81 int
  82 main (void)
  83 {
  84   test_clobber ();
  85   test_consistency ();
  86
  87   return test_exit_status;
  88 }