1 /* Copyright (C) 2003, 2004, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Martin Schwidefsky <schwidefsky@de.ibm.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, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <endian.h>
20 #include <errno.h>
21 #include <sysdep.h>
22 #include <lowlevellock.h>
23 #include <pthread.h>
24 #include <pthreadP.h>
25
26 #include <bits/kernel-features.h>
27
28
29 int
30 attribute_protected
__pthread_cond_signal(pthread_cond_t * cond)31 __pthread_cond_signal (
32 pthread_cond_t *cond)
33 {
34 int pshared = (cond->__data.__mutex == (void *) ~0l)
35 ? LLL_SHARED : LLL_PRIVATE;
36
37 /* Make sure we are alone. */
38 lll_lock (cond->__data.__lock, pshared);
39
40 /* Are there any waiters to be woken? */
41 if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
42 {
43 /* Yes. Mark one of them as woken. */
44 ++cond->__data.__wakeup_seq;
45 ++cond->__data.__futex;
46
47 /* Wake one. */
48 if (! __builtin_expect (lll_futex_wake_unlock (&cond->__data.__futex, 1,
49 1, &cond->__data.__lock,
50 pshared), 0))
51 return 0;
52
53 lll_futex_wake (&cond->__data.__futex, 1, pshared);
54 }
55
56 /* We are done. */
57 lll_unlock (cond->__data.__lock, pshared);
58
59 return 0;
60 }
61
62 weak_alias(__pthread_cond_signal, pthread_cond_signal)
63