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comparison include/SDL_mutex.h @ 0:74212992fb08

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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
parents
children b8688cfdc232
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-1:000000000000 0:74212992fb08
1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001 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@devolution.com
21 */
22
23 #ifdef SAVE_RCSID
24 static char rcsid =
25 "@(#) $Id$";
26 #endif
27
28 #ifndef _SDL_mutex_h
29 #define _SDL_mutex_h
30
31 /* Functions to provide thread synchronization primitives
32
33 These are independent of the other SDL routines.
34 */
35
36 #include "SDL_main.h"
37 #include "SDL_types.h"
38
39 #include "begin_code.h"
40 /* Set up for C function definitions, even when using C++ */
41 #ifdef __cplusplus
42 extern "C" {
43 #endif
44
45 /* Synchronization functions which can time out return this value
46 if they time out.
47 */
48 #define SDL_MUTEX_TIMEDOUT 1
49
50 /* This is the timeout value which corresponds to never time out */
51 #define SDL_MUTEX_MAXWAIT (~(Uint32)0)
52
53
54 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
55 /* Mutex functions */
56 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
57
58 /* The SDL mutex structure, defined in SDL_mutex.c */
59 struct SDL_mutex;
60 typedef struct SDL_mutex SDL_mutex;
61
62 /* Create a mutex, initialized unlocked */
63 extern DECLSPEC SDL_mutex * SDL_CreateMutex(void);
64
65 /* Lock the mutex (Returns 0, or -1 on error) */
66 #define SDL_LockMutex(m) SDL_mutexP(m)
67 extern DECLSPEC int SDL_mutexP(SDL_mutex *mutex);
68
69 /* Unlock the mutex (Returns 0, or -1 on error) */
70 #define SDL_UnlockMutex(m) SDL_mutexV(m)
71 extern DECLSPEC int SDL_mutexV(SDL_mutex *mutex);
72
73 /* Destroy a mutex */
74 extern DECLSPEC void SDL_DestroyMutex(SDL_mutex *mutex);
75
76
77 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
78 /* Semaphore functions */
79 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
80
81 /* The SDL semaphore structure, defined in SDL_sem.c */
82 struct SDL_semaphore;
83 typedef struct SDL_semaphore SDL_sem;
84
85 /* Create a semaphore, initialized with value, returns NULL on failure. */
86 extern DECLSPEC SDL_sem * SDL_CreateSemaphore(Uint32 initial_value);
87
88 /* Destroy a semaphore */
89 extern DECLSPEC void SDL_DestroySemaphore(SDL_sem *sem);
90
91 /* This function suspends the calling thread until the semaphore pointed
92 * to by sem has a positive count. It then atomically decreases the semaphore
93 * count.
94 */
95 extern DECLSPEC int SDL_SemWait(SDL_sem *sem);
96
97 /* Non-blocking variant of SDL_SemWait(), returns 0 if the wait succeeds,
98 SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.
99 */
100 extern DECLSPEC int SDL_SemTryWait(SDL_sem *sem);
101
102 /* Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if
103 the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in
104 the allotted time, and -1 on error.
105 On some platforms this function is implemented by looping with a delay
106 of 1 ms, and so should be avoided if possible.
107 */
108 extern DECLSPEC int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms);
109
110 /* Atomically increases the semaphore's count (not blocking), returns 0,
111 or -1 on error.
112 */
113 extern DECLSPEC int SDL_SemPost(SDL_sem *sem);
114
115 /* Returns the current count of the semaphore */
116 extern DECLSPEC Uint32 SDL_SemValue(SDL_sem *sem);
117
118
119 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
120 /* Condition variable functions */
121 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
122
123 /* The SDL condition variable structure, defined in SDL_cond.c */
124 struct SDL_cond;
125 typedef struct SDL_cond SDL_cond;
126
127 /* Create a condition variable */
128 extern DECLSPEC SDL_cond * SDL_CreateCond(void);
129
130 /* Destroy a condition variable */
131 extern DECLSPEC void SDL_DestroyCond(SDL_cond *cond);
132
133 /* Restart one of the threads that are waiting on the condition variable,
134 returns 0 or -1 on error.
135 */
136 extern DECLSPEC int SDL_CondSignal(SDL_cond *cond);
137
138 /* Restart all threads that are waiting on the condition variable,
139 returns 0 or -1 on error.
140 */
141 extern DECLSPEC int SDL_CondBroadcast(SDL_cond *cond);
142
143 /* Wait on the condition variable, unlocking the provided mutex.
144 The mutex must be locked before entering this function!
145 Returns 0 when it is signaled, or -1 on error.
146 */
147 extern DECLSPEC int SDL_CondWait(SDL_cond *cond, SDL_mutex *mut);
148
149 /* Waits for at most 'ms' milliseconds, and returns 0 if the condition
150 variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not
151 signaled in the allotted time, and -1 on error.
152 On some platforms this function is implemented by looping with a delay
153 of 1 ms, and so should be avoided if possible.
154 */
155 extern DECLSPEC int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms);
156
157 /* Ends C function definitions when using C++ */
158 #ifdef __cplusplus
159 }
160 #endif
161 #include "close_code.h"
162
163 #endif /* _SDL_mutex_h */