time/tst-gettimeofday.c

   1 /* Test gettimeofday function.
   2    Copyright (C) 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 <sys/time.h>
  20 #include <time.h>
  21
  22 #include <support/check.h>
  23 #include <support/test-driver.h>
  24
  25 /* Compare two struct timeval values, returning a value -1, 0 or 1.  */
  26
  27 int
  28 compare_timeval (const struct timeval *tv1, const struct timeval *tv2)
  29 {
  30   if (tv1->tv_sec < tv2->tv_sec)
  31     return -1;
  32   if (tv1->tv_sec > tv2->tv_sec)
  33     return 1;
  34   if (tv1->tv_usec < tv2->tv_usec)
  35     return -1;
  36   if (tv1->tv_usec > tv2->tv_usec)
  37     return 1;
  38   return 0;
  39 }
  40
  41 int
  42 do_test (void)
  43 {
  44   struct timeval tv1, tv2, tv3;
  45   int ret;
  46   time_t t1;
  47   /* Verify that the calls to gettimeofday succeed, that the time does
  48      not decrease, and that time returns a truncated (not rounded)
  49      version of the time.  */
  50   t1 = time (NULL);
  51   TEST_VERIFY_EXIT (t1 != (time_t) -1);
  52   ret = gettimeofday (&tv1, NULL);
  53   TEST_VERIFY_EXIT (ret == 0);
  54   TEST_VERIFY (t1 <= tv1.tv_sec);
  55   TEST_VERIFY (tv1.tv_usec >= 0);
  56   TEST_VERIFY (tv1.tv_usec < 1000000);
  57   ret = gettimeofday (&tv2, NULL);
  58   TEST_VERIFY_EXIT (ret == 0);
  59   TEST_VERIFY (compare_timeval (&tv1, &tv2) <= 0);
  60   TEST_VERIFY (tv2.tv_usec >= 0);
  61   TEST_VERIFY (tv2.tv_usec < 1000000);
  62   /* Also verify that after sleeping, the time returned has increased.
  63      Repeat several times to verify that each time, the time from the
  64      time function is truncated not rounded.  */
  65   const struct timespec duration = { .tv_nsec = 100000000 };
  66   for (int i = 0; i < 10; i++)
  67     {
  68       ret = nanosleep (&duration, NULL);
  69       TEST_VERIFY_EXIT (ret == 0);
  70       t1 = time (NULL);
  71       TEST_VERIFY_EXIT (t1 != (time_t) -1);
  72       ret = gettimeofday (&tv3, NULL);
  73       TEST_VERIFY_EXIT (ret == 0);
  74       TEST_VERIFY (compare_timeval (&tv2, &tv3) < 0);
  75       TEST_VERIFY (t1 <= tv3.tv_sec);
  76       TEST_VERIFY (tv3.tv_usec >= 0);
  77       TEST_VERIFY (tv3.tv_usec < 1000000);
  78       tv2 = tv3;
  79     }
  80   /* Also test with the obsolete tz argument not being NULL.  */
  81   struct timezone tz = { 0 };
  82   t1 = time (NULL);
  83   TEST_VERIFY_EXIT (t1 != (time_t) -1);
  84   ret = gettimeofday (&tv3, &tz);
  85   TEST_VERIFY_EXIT (ret == 0);
  86   TEST_VERIFY (t1 <= tv3.tv_sec);
  87   TEST_VERIFY (compare_timeval (&tv2, &tv3) <= 0);
  88   TEST_VERIFY (tv3.tv_usec >= 0);
  89   TEST_VERIFY (tv3.tv_usec < 1000000);
  90   return 0;
  91 }
  92
  93 #include <support/test-driver.c>