1 /*
2 * pthread_rwlockattr_setpshared.c
3 *
4 * Description:
5 * This translation unit implements read/write 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 <limits.h>
38
39 #include "pthread.h"
40 #include "implement.h"
41
42 int
pthread_rwlockattr_setpshared(pthread_rwlockattr_t * attr,int pshared)43 pthread_rwlockattr_setpshared (pthread_rwlockattr_t * attr, int pshared)
44 /*
45 * ------------------------------------------------------
46 * DOCPUBLIC
47 * Rwlocks created with 'attr' can be shared between
48 * processes if pthread_rwlock_t variable is allocated
49 * in memory shared by these processes.
50 *
51 * PARAMETERS
52 * attr
53 * pointer to an instance of pthread_rwlockattr_t
54 *
55 * pshared
56 * must be one of:
57 *
58 * PTHREAD_PROCESS_SHARED
59 * May be shared if in shared memory
60 *
61 * PTHREAD_PROCESS_PRIVATE
62 * Cannot be shared.
63 *
64 * DESCRIPTION
65 * Rwlocks creatd with 'attr' can be shared between
66 * processes if pthread_rwlock_t variable is allocated
67 * in memory shared by these processes.
68 *
69 * NOTES:
70 * 1) pshared rwlocks MUST be allocated in shared
71 * memory.
72 *
73 * 2) The following macro is defined if shared rwlocks
74 * are supported:
75 * _POSIX_THREAD_PROCESS_SHARED
76 *
77 * RESULTS
78 * 0 successfully set attribute,
79 * EINVAL 'attr' or pshared is invalid,
80 * ENOSYS PTHREAD_PROCESS_SHARED not supported,
81 *
82 * ------------------------------------------------------
83 */
84 {
85 int result;
86
87 if ((attr != NULL && *attr != NULL) &&
88 ((pshared == PTHREAD_PROCESS_SHARED) ||
89 (pshared == PTHREAD_PROCESS_PRIVATE)))
90 {
91 if (pshared == PTHREAD_PROCESS_SHARED)
92 {
93
94 #if !defined( _POSIX_THREAD_PROCESS_SHARED )
95
96 result = ENOSYS;
97 pshared = PTHREAD_PROCESS_PRIVATE;
98
99 #else
100
101 result = 0;
102
103 #endif /* _POSIX_THREAD_PROCESS_SHARED */
104
105 }
106 else
107 {
108 result = 0;
109 }
110
111 (*attr)->pshared = pshared;
112 }
113 else
114 {
115 result = EINVAL;
116 }
117
118 return (result);
119
120 } /* pthread_rwlockattr_setpshared */
121