1 /* 2 * pthread_rwlockattr_setpshared.c 3 * 4 * Description: 5 * This translation unit implements read/write lock primitives. 6 * 7 * -------------------------------------------------------------------------- 8 * 9 * Pthreads-embedded (PTE) - POSIX Threads Library for embedded systems 10 * Copyright(C) 2008 Jason Schmidlapp 11 * 12 * Contact Email: jschmidlapp@users.sourceforge.net 13 * 14 * 15 * Based upon Pthreads-win32 - POSIX Threads Library for Win32 16 * Copyright(C) 1998 John E. Bossom 17 * Copyright(C) 1999,2005 Pthreads-win32 contributors 18 * 19 * Contact Email: rpj@callisto.canberra.edu.au 20 * 21 * The original list of contributors to the Pthreads-win32 project 22 * is contained in the file CONTRIBUTORS.ptw32 included with the 23 * source code distribution. The list can also be seen at the 24 * following World Wide Web location: 25 * http://sources.redhat.com/pthreads-win32/contributors.html 26 * 27 * This library is free software; you can redistribute it and/or 28 * modify it under the terms of the GNU Lesser General Public 29 * License as published by the Free Software Foundation; either 30 * version 2 of the License, or (at your option) any later version. 31 * 32 * This library is distributed in the hope that it will be useful, 33 * but WITHOUT ANY WARRANTY; without even the implied warranty of 34 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 35 * Lesser General Public License for more details. 36 * 37 * You should have received a copy of the GNU Lesser General Public 38 * License along with this library in the file COPYING.LIB; 39 * if not, write to the Free Software Foundation, Inc., 40 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 41 */ 42 43 #include <errno.h> 44 #include <limits.h> 45 46 #include "pthread.h" 47 #include "implement.h" 48 49 int 50 pthread_rwlockattr_setpshared (pthread_rwlockattr_t * attr, int pshared) 51 /* 52 * ------------------------------------------------------ 53 * DOCPUBLIC 54 * Rwlocks created with 'attr' can be shared between 55 * processes if pthread_rwlock_t variable is allocated 56 * in memory shared by these processes. 57 * 58 * PARAMETERS 59 * attr 60 * pointer to an instance of pthread_rwlockattr_t 61 * 62 * pshared 63 * must be one of: 64 * 65 * PTHREAD_PROCESS_SHARED 66 * May be shared if in shared memory 67 * 68 * PTHREAD_PROCESS_PRIVATE 69 * Cannot be shared. 70 * 71 * DESCRIPTION 72 * Rwlocks creatd with 'attr' can be shared between 73 * processes if pthread_rwlock_t variable is allocated 74 * in memory shared by these processes. 75 * 76 * NOTES: 77 * 1) pshared rwlocks MUST be allocated in shared 78 * memory. 79 * 80 * 2) The following macro is defined if shared rwlocks 81 * are supported: 82 * _POSIX_THREAD_PROCESS_SHARED 83 * 84 * RESULTS 85 * 0 successfully set attribute, 86 * EINVAL 'attr' or pshared is invalid, 87 * ENOSYS PTHREAD_PROCESS_SHARED not supported, 88 * 89 * ------------------------------------------------------ 90 */ 91 { 92 int result; 93 94 if ((attr != NULL && *attr != NULL) && 95 ((pshared == PTHREAD_PROCESS_SHARED) || 96 (pshared == PTHREAD_PROCESS_PRIVATE))) 97 { 98 if (pshared == PTHREAD_PROCESS_SHARED) 99 { 100 101 #if !defined( _POSIX_THREAD_PROCESS_SHARED ) 102 103 result = ENOSYS; 104 pshared = PTHREAD_PROCESS_PRIVATE; 105 106 #else 107 108 result = 0; 109 110 #endif /* _POSIX_THREAD_PROCESS_SHARED */ 111 112 } 113 else 114 { 115 result = 0; 116 } 117 118 (*attr)->pshared = pshared; 119 } 120 else 121 { 122 result = EINVAL; 123 } 124 125 return (result); 126 127 } /* pthread_rwlockattr_setpshared */ 128