1  /* pthread_condattr_setclock.  Generic version.
       2     Copyright (C) 2002-2023 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 <pthread.h>
      20  #include <pt-internal.h>
      21  
      22  int
      23  pthread_condattr_setclock (pthread_condattr_t *attr, clockid_t clock)
      24  {
      25    /* Only a few clocks are allowed.  CLOCK_REALTIME is always allowed.
      26       CLOCK_MONOTONIC only if the kernel has the necessary support.  */
      27    if (clock == CLOCK_MONOTONIC)
      28      {
      29        /* Check whether the clock is available.  */
      30        static int avail;
      31  
      32        if (avail == 0)
      33  	{
      34  	  struct timespec ts;
      35  	  int res;
      36  
      37  	  res = clock_gettime (CLOCK_MONOTONIC, &ts);
      38  	  avail = res < 0 ? -1 : 1;
      39  	}
      40  
      41        if (avail < 0)
      42  	/* Not available.  */
      43  	return EINVAL;
      44      }
      45    else if (clock != CLOCK_REALTIME)
      46      return EINVAL;
      47  
      48    attr->__clock = clock;
      49  
      50    return 0;
      51  }