1 /*
2 * pthread_spin_destroy.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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
35 */
36
37 #include "pthread.h"
38 #include "implement.h"
39
40
41 int
pthread_spin_destroy(pthread_spinlock_t * lock)42 pthread_spin_destroy (pthread_spinlock_t * lock)
43 {
44 register pthread_spinlock_t s;
45 int result = 0;
46
47 if (lock == NULL || *lock == NULL)
48 {
49 return EINVAL;
50 }
51
52 if ((s = *lock) != PTHREAD_SPINLOCK_INITIALIZER)
53 {
54 if (s->interlock == PTW32_SPIN_USE_MUTEX)
55 {
56 result = pthread_mutex_destroy (&(s->u.mutex));
57 }
58 else if ((PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED !=
59 PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR) &s->interlock,
60 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_INVALID,
61 (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED))
62 {
63 result = EINVAL;
64 }
65
66 if (0 == result)
67 {
68 /*
69 * We are relying on the application to ensure that all other threads
70 * have finished with the spinlock before destroying it.
71 */
72 *lock = NULL;
73 (void) free (s);
74 }
75 }
76 else
77 {
78 /*
79 * See notes in ptw32_spinlock_check_need_init() above also.
80 */
81 ptw32_mcs_local_node_t node;
82
83 ptw32_mcs_lock_acquire(&ptw32_spinlock_test_init_lock, &node);
84
85 /*
86 * Check again.
87 */
88 if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
89 {
90 /*
91 * This is all we need to do to destroy a statically
92 * initialised spinlock that has not yet been used (initialised).
93 * If we get to here, another thread
94 * waiting to initialise this mutex will get an EINVAL.
95 */
96 *lock = NULL;
97 }
98 else
99 {
100 /*
101 * The spinlock has been initialised while we were waiting
102 * so assume it's in use.
103 */
104 result = EBUSY;
105 }
106
107 ptw32_mcs_lock_release(&node);
108 }
109
110 return (result);
111 }
112