2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
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.
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.
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
25 "@(#) $Id: SDL_mutex.h,v 1.6 2002/06/13 23:59:20 slouken Exp $";
31 /* Functions to provide thread synchronization primitives
33 These are independent of the other SDL routines.
37 #include "SDL_types.h"
39 #include "begin_code.h"
40 /* Set up for C function definitions, even when using C++ */
45 /* Synchronization functions which can time out return this value
48 #define SDL_MUTEX_TIMEDOUT 1
50 /* This is the timeout value which corresponds to never time out */
51 #define SDL_MUTEX_MAXWAIT (~(Uint32)0)
54 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
56 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
58 /* The SDL mutex structure, defined in SDL_mutex.c */
60 typedef struct SDL_mutex SDL_mutex;
62 /* Create a mutex, initialized unlocked */
63 extern DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void);
65 /* Lock the mutex (Returns 0, or -1 on error) */
66 #define SDL_LockMutex(m) SDL_mutexP(m)
67 extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex);
69 /* Unlock the mutex (Returns 0, or -1 on error)
70 It is an error to unlock a mutex that has not been locked by
71 the current thread, and doing so results in undefined behavior.
73 #define SDL_UnlockMutex(m) SDL_mutexV(m)
74 extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex);
77 extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex);
80 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
81 /* Semaphore functions */
82 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
84 /* The SDL semaphore structure, defined in SDL_sem.c */
86 typedef struct SDL_semaphore SDL_sem;
88 /* Create a semaphore, initialized with value, returns NULL on failure. */
89 extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
91 /* Destroy a semaphore */
92 extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem);
94 /* This function suspends the calling thread until the semaphore pointed
95 * to by sem has a positive count. It then atomically decreases the semaphore
98 extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem);
100 /* Non-blocking variant of SDL_SemWait(), returns 0 if the wait succeeds,
101 SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.
103 extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem);
105 /* Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if
106 the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in
107 the allotted time, and -1 on error.
108 On some platforms this function is implemented by looping with a delay
109 of 1 ms, and so should be avoided if possible.
111 extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms);
113 /* Atomically increases the semaphore's count (not blocking), returns 0,
116 extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem);
118 /* Returns the current count of the semaphore */
119 extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem);
122 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
123 /* Condition variable functions */
124 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
126 /* The SDL condition variable structure, defined in SDL_cond.c */
128 typedef struct SDL_cond SDL_cond;
130 /* Create a condition variable */
131 extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void);
133 /* Destroy a condition variable */
134 extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond);
136 /* Restart one of the threads that are waiting on the condition variable,
137 returns 0 or -1 on error.
139 extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond);
141 /* Restart all threads that are waiting on the condition variable,
142 returns 0 or -1 on error.
144 extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond);
146 /* Wait on the condition variable, unlocking the provided mutex.
147 The mutex must be locked before entering this function!
148 Returns 0 when it is signaled, or -1 on error.
150 extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut);
152 /* Waits for at most 'ms' milliseconds, and returns 0 if the condition
153 variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not
154 signaled in the allotted time, and -1 on error.
155 On some platforms this function is implemented by looping with a delay
156 of 1 ms, and so should be avoided if possible.
158 extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms);
160 /* Ends C function definitions when using C++ */
164 #include "close_code.h"
166 #endif /* _SDL_mutex_h */