2005-02-22 Roland McGrath <roland@redhat.com>
[glibc.git] / nptl / pthread_condattr_setclock.c
blob04e246b74dd4fa49fb82776b73df6547d46b7fe9
1 /* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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.
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.
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. */
20 #include <assert.h>
21 #include <errno.h>
22 #include <stdbool.h>
23 #include <time.h>
24 #include <sysdep.h>
25 #include "pthreadP.h"
26 #include <kernel-features.h>
29 int
30 pthread_condattr_setclock (attr, clock_id)
31 pthread_condattr_t *attr;
32 clockid_t clock_id;
34 /* Only a few clocks are allowed. CLOCK_REALTIME is always allowed.
35 CLOCK_MONOTONIC only if the kernel has the necessary support. */
36 if (clock_id == CLOCK_MONOTONIC)
38 #ifndef __ASSUME_POSIX_TIMERS
39 # ifdef __NR_clock_getres
40 /* Check whether the clock is available. */
41 static int avail;
43 if (avail == 0)
45 struct timespec ts;
47 INTERNAL_SYSCALL_DECL (err);
48 int val;
49 val = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
50 avail = INTERNAL_SYSCALL_ERROR_P (val, err) ? -1 : 1;
53 if (avail < 0)
54 # endif
55 /* Not available. */
56 return EINVAL;
57 #endif
59 else if (clock_id != CLOCK_REALTIME)
60 /* If more clocks are allowed some day the storing of the clock ID
61 in the pthread_cond_t structure needs to be adjusted. */
62 return EINVAL;
64 /* Make sure the value fits in the bits we reserved. */
65 assert (clock_id < (1 << COND_CLOCK_BITS));
67 int *valuep = &((struct pthread_condattr *) attr)->value;
69 *valuep = (*valuep & ~(1 << (COND_CLOCK_BITS + 1)) & ~1) | (clock_id << 1);
71 return 0;