1 /*
2 * pthread_spin_init.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_init(pthread_spinlock_t * lock,int pshared)42 pthread_spin_init (pthread_spinlock_t * lock, int pshared)
43 {
44 pthread_spinlock_t s;
45 int cpus = 0;
46 int result = 0;
47
48 if (lock == NULL)
49 {
50 return EINVAL;
51 }
52
53 if (0 != ptw32_getprocessors (&cpus))
54 {
55 cpus = 1;
56 }
57
58 if (cpus > 1)
59 {
60 if (pshared == PTHREAD_PROCESS_SHARED)
61 {
62 /*
63 * Creating spinlock that can be shared between
64 * processes.
65 */
66 #if _POSIX_THREAD_PROCESS_SHARED >= 0
67
68 /*
69 * Not implemented yet.
70 */
71
72 #error ERROR [__FILE__, line __LINE__]: Process shared spin locks are not supported yet.
73
74 #else
75
76 return ENOSYS;
77
78 #endif /* _POSIX_THREAD_PROCESS_SHARED */
79
80 }
81 }
82
83 s = (pthread_spinlock_t) calloc (1, sizeof (*s));
84
85 if (s == NULL)
86 {
87 return ENOMEM;
88 }
89
90 if (cpus > 1)
91 {
92 s->u.cpus = cpus;
93 s->interlock = PTW32_SPIN_UNLOCKED;
94 }
95 else
96 {
97 pthread_mutexattr_t ma;
98 result = pthread_mutexattr_init (&ma);
99
100 if (0 == result)
101 {
102 ma->pshared = pshared;
103 result = pthread_mutex_init (&(s->u.mutex), &ma);
104 if (0 == result)
105 {
106 s->interlock = PTW32_SPIN_USE_MUTEX;
107 }
108 }
109 (void) pthread_mutexattr_destroy (&ma);
110 }
111
112 if (0 == result)
113 {
114 *lock = s;
115 }
116 else
117 {
118 (void) free (s);
119 *lock = NULL;
120 }
121
122 return (result);
123 }
124