1 /*
2 * pthread_spin_unlock.c
3 *
4 * Description:
5 * This translation unit implements spin lock primitives.
6 *
7 * --------------------------------------------------------------------------
8 *
9 * Pthreads-win32 - POSIX Threads Library for Win32
10 * Copyright(C) 1998 John E. Bossom
11 * Copyright(C) 1999,2005 Pthreads-win32 contributors
12 *
13 * Contact Email: rpj@callisto.canberra.edu.au
14 *
15 * The current list of contributors is contained
16 * in the file CONTRIBUTORS included with the source
17 * code distribution. The list can also be seen at the
18 * following World Wide Web location:
19 * http://sources.redhat.com/pthreads-win32/contributors.html
20 *
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Lesser General Public
23 * License as published by the Free Software Foundation; either
24 * version 2 of the License, or (at your option) any later version.
25 *
26 * This library is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
29 * Lesser General Public License for more details.
30 *
31 * You should have received a copy of the GNU Lesser General Public
32 * License along with this library in the file COPYING.LIB;
33 * if not, write to the Free Software Foundation, Inc.,
34 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
35 */
36
37 #include "pthread.h"
38 #include "implement.h"
39
40
41 int
pthread_spin_unlock(pthread_spinlock_t * lock)42 pthread_spin_unlock (pthread_spinlock_t * lock)
43 {
44 register pthread_spinlock_t s;
45
46 if (NULL == lock || NULL == *lock)
47 {
48 return (EINVAL);
49 }
50
51 s = *lock;
52
53 if (s == PTHREAD_SPINLOCK_INITIALIZER)
54 {
55 return EPERM;
56 }
57
58 switch ((long)
59 PTW32_INTERLOCKED_COMPARE_EXCHANGE ((PTW32_INTERLOCKED_LPLONG) &
60 (s->interlock),
61 (PTW32_INTERLOCKED_LONG)
62 PTW32_SPIN_UNLOCKED,
63 (PTW32_INTERLOCKED_LONG)
64 PTW32_SPIN_LOCKED))
65 {
66 case PTW32_SPIN_LOCKED:
67 return 0;
68 case PTW32_SPIN_UNLOCKED:
69 return EPERM;
70 case PTW32_SPIN_USE_MUTEX:
71 return pthread_mutex_unlock (&(s->u.mutex));
72 }
73
74 return EINVAL;
75 }
76