1  /* Test setting the monotonic clock.
       2     Copyright (C) 2007-2023 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 <errno.h>
      20  #include <support/check.h>
      21  #include <time.h>
      22  #include <unistd.h>
      23  
      24  int
      25  do_test (void)
      26  {
      27  #if defined CLOCK_MONOTONIC && defined _POSIX_MONOTONIC_CLOCK
      28    if (sysconf (_SC_MONOTONIC_CLOCK) <= 0)
      29      FAIL_UNSUPPORTED ("_SC_MONOTONIC_CLOCK not supported");
      30  
      31    struct timespec ts;
      32    TEST_COMPARE (clock_gettime (CLOCK_MONOTONIC, &ts), 0);
      33  
      34    /* Setting the monotonic clock must fail.  */
      35    TEST_VERIFY (clock_settime (CLOCK_MONOTONIC, &ts) == -1);
      36    TEST_VERIFY (errno == EINVAL || errno == EPERM);
      37  
      38    return 0;
      39  #else
      40    return EXIT_UNSUPPORTED;
      41  #endif
      42  }
      43  
      44  #include <support/test-driver.c>