1 /*
2 * pthread_rwlockattr_getpshared.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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
35 */
36
37 #include <limits.h>
38
39 #include "pthread.h"
40 #include "implement.h"
41
42 int
pthread_rwlockattr_getpshared(const pthread_rwlockattr_t * attr,int * pshared)43 pthread_rwlockattr_getpshared (const pthread_rwlockattr_t * attr,
44 int *pshared)
45 /*
46 * ------------------------------------------------------
47 * DOCPUBLIC
48 * Determine whether rwlocks created with 'attr' can be
49 * shared between processes.
50 *
51 * PARAMETERS
52 * attr
53 * pointer to an instance of pthread_rwlockattr_t
54 *
55 * pshared
56 * will be set to 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 *
65 * DESCRIPTION
66 * Rwlocks creatd with 'attr' can be shared between
67 * processes if pthread_rwlock_t variable is allocated
68 * in memory shared by these processes.
69 * NOTES:
70 * 1) pshared rwlocks MUST be allocated in shared
71 * memory.
72 * 2) The following macro is defined if shared rwlocks
73 * are supported:
74 * _POSIX_THREAD_PROCESS_SHARED
75 *
76 * RESULTS
77 * 0 successfully retrieved attribute,
78 * EINVAL 'attr' is invalid,
79 *
80 * ------------------------------------------------------
81 */
82 {
83 int result;
84
85 if ((attr != NULL && *attr != NULL) && (pshared != NULL))
86 {
87 *pshared = (*attr)->pshared;
88 result = 0;
89 }
90 else
91 {
92 result = EINVAL;
93 }
94
95 return (result);
96
97 } /* pthread_rwlockattr_getpshared */
98