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
41int
42pthread_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