Mercurial > sdl-ios-xcode

comparison src/thread/pthread/SDL_sysmutex.c @ 1361:19418e4422cb

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
New configure-based build system. Still work in progress, but much improved
author Sam Lantinga <slouken@libsdl.org>
date Thu, 16 Feb 2006 10:11:48 +0000
parents
children d910939febfa
comparison
equal deleted inserted replaced
1360:70a9cfb4cf1b 1361:19418e4422cb
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2006 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22
23 #include <pthread.h>
24
25 #include "SDL_thread.h"
26
27 #if !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX && \
28 !SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
29 #define FAKE_RECURSIVE_MUTEX
30 #endif
31
32 struct SDL_mutex {
33 pthread_mutex_t id;
34 #if FAKE_RECURSIVE_MUTEX
35 int recursive;
36 pthread_t owner;
37 #endif
38 };
39
40 SDL_mutex *SDL_CreateMutex (void)
41 {
42 SDL_mutex *mutex;
43 pthread_mutexattr_t attr;
44
45 /* Allocate the structure */
46 mutex = (SDL_mutex *)SDL_calloc(1, sizeof(*mutex));
47 if ( mutex ) {
48 pthread_mutexattr_init(&attr);
49 #if SDL_THREAD_PTHREAD_RECURSIVE_MUTEX
50 pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
51 #elif SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP
52 pthread_mutexattr_setkind_np(&attr, PTHREAD_MUTEX_RECURSIVE_NP);
53 #else
54 /* No extra attributes necessary */
55 #endif
56 if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
57 SDL_SetError("pthread_mutex_init() failed");
58 SDL_free(mutex);
59 mutex = NULL;
60 }
61 } else {
62 SDL_OutOfMemory();
63 }
64 return(mutex);
65 }
66
67 void SDL_DestroyMutex(SDL_mutex *mutex)
68 {
69 if ( mutex ) {
70 pthread_mutex_destroy(&mutex->id);
71 SDL_free(mutex);
72 }
73 }
74
75 /* Lock the mutex */
76 int SDL_mutexP(SDL_mutex *mutex)
77 {
78 int retval;
79 #if FAKE_RECURSIVE_MUTEX
80 pthread_t this_thread;
81 #endif
82
83 if ( mutex == NULL ) {
84 SDL_SetError("Passed a NULL mutex");
85 return -1;
86 }
87
88 retval = 0;
89 #if FAKE_RECURSIVE_MUTEX
90 this_thread = pthread_self();
91 if ( mutex->owner == this_thread ) {
92 ++mutex->recursive;
93 } else {
94 /* The order of operations is important.
95 We set the locking thread id after we obtain the lock
96 so unlocks from other threads will fail.
97 */
98 if ( pthread_mutex_lock(&mutex->id) == 0 ) {
99 mutex->owner = this_thread;
100 mutex->recursive = 0;
101 } else {
102 SDL_SetError("pthread_mutex_lock() failed");
103 retval = -1;
104 }
105 }
106 #else
107 if ( pthread_mutex_lock(&mutex->id) < 0 ) {
108 SDL_SetError("pthread_mutex_lock() failed");
109 retval = -1;
110 }
111 #endif
112 return retval;
113 }
114
115 int SDL_mutexV(SDL_mutex *mutex)
116 {
117 int retval;
118
119 if ( mutex == NULL ) {
120 SDL_SetError("Passed a NULL mutex");
121 return -1;
122 }
123
124 retval = 0;
125 #if FAKE_RECURSIVE_MUTEX
126 /* We can only unlock the mutex if we own it */
127 if ( pthread_self() == mutex->owner ) {
128 if ( mutex->recursive ) {
129 --mutex->recursive;
130 } else {
131 /* The order of operations is important.
132 First reset the owner so another thread doesn't lock
133 the mutex and set the ownership before we reset it,
134 then release the lock semaphore.
135 */
136 mutex->owner = 0;
137 pthread_mutex_unlock(&mutex->id);
138 }
139 } else {
140 SDL_SetError("mutex not owned by this thread");
141 retval = -1;
142 }
143
144 #else
145 if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
146 SDL_SetError("pthread_mutex_unlock() failed");
147 retval = -1;
148 }
149 #endif /* FAKE_RECURSIVE_MUTEX */
150
151 return retval;
152 }