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comparison src/thread/riscos/SDL_sysmutex.c @ 955:d74fbf56f2f6

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Date: Fri, 25 Jun 2004 13:29:15 +0100 From: "alan buckley" Subject: Modification for RISC OS version of SDL Ive attached a zip file with the changes to this email, it contains the following: The file sdldiff.txt is the output from cvs diff u. . The directory thread/riscos contains all the new files to support threading. Readme.riscos is a new readme file to add.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 17 Sep 2004 13:20:10 +0000
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954:3acd16ea0180 955:d74fbf56f2f6
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2004 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public
7 License as published by the Free Software Foundation; either
8 version 2 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
14
15 You should have received a copy of the GNU Library General Public
16 License along with this library; if not, write to the Free
17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22
23 /* RISC OS implementations uses pthreads based on linux code */
24
25 #ifdef SAVE_RCSID
26 static char rcsid =
27 "@(#) $Id$";
28 #endif
29
30 #ifdef DISABLE_THREADS
31 #include "../generic/SDL_sysmutex.c"
32 #else
33
34 #include <stdlib.h>
35 #include <stdio.h>
36 #include <pthread.h>
37
38 #include "SDL_error.h"
39 #include "SDL_thread.h"
40
41 struct SDL_mutex {
42 pthread_mutex_t id;
43 #ifdef PTHREAD_NO_RECURSIVE_MUTEX
44 int recursive;
45 pthread_t owner;
46 #endif
47 };
48
49 SDL_mutex *SDL_CreateMutex (void)
50 {
51 SDL_mutex *mutex;
52 pthread_mutexattr_t attr;
53
54 /* Allocate the structure */
55 mutex = (SDL_mutex *)calloc(1, sizeof(*mutex));
56 if ( mutex ) {
57 pthread_mutexattr_init(&attr);
58 #ifdef PTHREAD_NO_RECURSIVE_MUTEX
59 /* No extra attributes necessary */
60 #else
61 pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
62 #endif /* PTHREAD_NO_RECURSIVE_MUTEX */
63 if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
64 SDL_SetError("pthread_mutex_init() failed");
65 free(mutex);
66 mutex = NULL;
67 }
68 } else {
69 SDL_OutOfMemory();
70 }
71 return(mutex);
72 }
73
74 void SDL_DestroyMutex(SDL_mutex *mutex)
75 {
76 if ( mutex ) {
77 pthread_mutex_destroy(&mutex->id);
78 free(mutex);
79 }
80 }
81
82 /* Lock the mutex */
83 int SDL_mutexP(SDL_mutex *mutex)
84 {
85 int retval;
86 #ifdef PTHREAD_NO_RECURSIVE_MUTEX
87 pthread_t this_thread;
88 #endif
89
90 if ( mutex == NULL ) {
91 SDL_SetError("Passed a NULL mutex");
92 return -1;
93 }
94
95 retval = 0;
96 #ifdef PTHREAD_NO_RECURSIVE_MUTEX
97 this_thread = pthread_self();
98 if ( mutex->owner == this_thread ) {
99 ++mutex->recursive;
100 } else {
101 /* The order of operations is important.
102 We set the locking thread id after we obtain the lock
103 so unlocks from other threads will fail.
104 */
105 if ( pthread_mutex_lock(&mutex->id) == 0 ) {
106 mutex->owner = this_thread;
107 mutex->recursive = 0;
108 } else {
109 SDL_SetError("pthread_mutex_lock() failed");
110 retval = -1;
111 }
112 }
113 #else
114 if ( pthread_mutex_lock(&mutex->id) < 0 ) {
115 SDL_SetError("pthread_mutex_lock() failed");
116 retval = -1;
117 }
118 #endif
119 return retval;
120 }
121
122 int SDL_mutexV(SDL_mutex *mutex)
123 {
124 int retval;
125
126 if ( mutex == NULL ) {
127 SDL_SetError("Passed a NULL mutex");
128 return -1;
129 }
130
131 retval = 0;
132 #ifdef PTHREAD_NO_RECURSIVE_MUTEX
133 /* We can only unlock the mutex if we own it */
134 if ( pthread_self() == mutex->owner ) {
135 if ( mutex->recursive ) {
136 --mutex->recursive;
137 } else {
138 /* The order of operations is important.
139 First reset the owner so another thread doesn't lock
140 the mutex and set the ownership before we reset it,
141 then release the lock semaphore.
142 */
143 mutex->owner = 0;
144 pthread_mutex_unlock(&mutex->id);
145 }
146 } else {
147 SDL_SetError("mutex not owned by this thread");
148 retval = -1;
149 }
150
151 #else
152 if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
153 SDL_SetError("pthread_mutex_unlock() failed");
154 retval = -1;
155 }
156 #endif /* PTHREAD_NO_RECURSIVE_MUTEX */
157
158 return retval;
159 }
160 #endif