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  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. #ifdef SAVE_RCSID
  24. static char rcsid =
  25.  "@(#) $Id: SDL_mutex.h,v 1.7 2004/01/04 16:49:07 slouken Exp $";
  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 * SDLCALL 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 SDLCALL SDL_mutexP(SDL_mutex *mutex);
  68.  
  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.
  72.  */
  73. #define SDL_UnlockMutex(m)      SDL_mutexV(m)
  74. extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex);
  75.  
  76. /* Destroy a mutex */
  77. extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex *mutex);
  78.  
  79.  
  80. /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  81. /* Semaphore functions                                           */
  82. /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  83.  
  84. /* The SDL semaphore structure, defined in SDL_sem.c */
  85. struct SDL_semaphore;
  86. typedef struct SDL_semaphore SDL_sem;
  87.  
  88. /* Create a semaphore, initialized with value, returns NULL on failure. */
  89. extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
  90.  
  91. /* Destroy a semaphore */
  92. extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem);
  93.  
  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
  96.  * count.
  97.  */
  98. extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem);
  99.  
  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.
  102. */
  103. extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem);
  104.  
  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.
  110. */
  111. extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms);
  112.  
  113. /* Atomically increases the semaphore's count (not blocking), returns 0,
  114.    or -1 on error.
  115.  */
  116. extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem);
  117.  
  118. /* Returns the current count of the semaphore */
  119. extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem);
  120.  
  121.  
  122. /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  123. /* Condition variable functions                                  */
  124. /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
  125.  
  126. /* The SDL condition variable structure, defined in SDL_cond.c */
  127. struct SDL_cond;
  128. typedef struct SDL_cond SDL_cond;
  129.  
  130. /* Create a condition variable */
  131. extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void);
  132.  
  133. /* Destroy a condition variable */
  134. extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond);
  135.  
  136. /* Restart one of the threads that are waiting on the condition variable,
  137.    returns 0 or -1 on error.
  138.  */
  139. extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond);
  140.  
  141. /* Restart all threads that are waiting on the condition variable,
  142.    returns 0 or -1 on error.
  143.  */
  144. extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond);
  145.  
  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.
  149.  */
  150. extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut);
  151.  
  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.
  157. */
  158. extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms);
  159.  
  160. /* Ends C function definitions when using C++ */
  161. #ifdef __cplusplus
  162. }
  163. #endif
  164. #include "close_code.h"
  165.  
  166. #endif /* _SDL_mutex_h */
  167.