nptl/pthread_condattr_setclock.c

   1 /* Copyright (C) 2003 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
   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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <stdbool.h>
  22 #include <time.h>
  23 #include <sysdep.h>
  24 #include "pthreadP.h"
  25 #include <kernel-features.h>
  26
  27
  28 int
  29 pthread_condattr_setclock (attr, clock_id)
  30      pthread_condattr_t *attr;
  31      clockid_t clock_id;
  32 {
  33   /* Only a few clocks are allowed.  CLOCK_REALTIME is always allowed.
  34      CLOCK_MONOTONIC only if the kernel has the necessary support.  */
  35   if (clock_id == CLOCK_MONOTONIC)
  36     {
  37 #ifndef __ASSUME_POSIX_TIMERS
  38 # ifdef __NR_clock_getres
  39       /* Check whether the clock is available.  */
  40       static int avail;
  41
  42       if (avail == 0)
  43         {
  44           struct timespec ts;
  45
  46           INTERNAL_SYSCALL_DECL (err);
  47           int val;
  48           val = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC,
  49                                   &ts);
  50           avail = INTERNAL_SYSCALL_ERROR_P (val, err) ? -1 : 1;
  51         }
  52
  53       if (avail < 0)
  54 # endif
  55         /* Not available.  */
  56         return EINVAL;
  57 #endif
  58     }
  59   else if (clock_id != CLOCK_REALTIME)
  60     return EINVAL;
  61
  62   int *valuep = &((struct pthread_condattr *) attr)->value;
  63
  64   *valuep = (*valuep & ~0xfe) | (clock_id << 1);
  65
  66   return 0;
  67 }