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
42int
43pthread_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