glibc/nptl/pthread_condattr_setclock.c

73 lines
2.2 KiB
C

/* Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <time.h>
#include <sysdep.h>
#include "pthreadP.h"
#include <kernel-features.h>
int
pthread_condattr_setclock (attr, clock_id)
pthread_condattr_t *attr;
clockid_t clock_id;
{
/* Only a few clocks are allowed. CLOCK_REALTIME is always allowed.
CLOCK_MONOTONIC only if the kernel has the necessary support. */
if (clock_id == CLOCK_MONOTONIC)
{
#ifndef __ASSUME_POSIX_TIMERS
# ifdef __NR_clock_getres
/* Check whether the clock is available. */
static int avail;
if (avail == 0)
{
struct timespec ts;
INTERNAL_SYSCALL_DECL (err);
int val;
val = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
avail = INTERNAL_SYSCALL_ERROR_P (val, err) ? -1 : 1;
}
if (avail < 0)
# endif
/* Not available. */
return EINVAL;
#endif
}
else if (clock_id != CLOCK_REALTIME)
/* If more clocks are allowed some day the storing of the clock ID
in the pthread_cond_t structure needs to be adjusted. */
return EINVAL;
/* Make sure the value fits in the bits we reserved. */
assert (clock_id < (1 << COND_NWAITERS_SHIFT));
int *valuep = &((struct pthread_condattr *) attr)->value;
*valuep = ((*valuep & ~(((1 << COND_NWAITERS_SHIFT) - 1) << 1))
| (clock_id << 1));
return 0;
}