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