sysdeps/htl/pt-condattr-setclock.c

   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 }