include/SDL_mutex.h
author Sam Lantinga <slouken@libsdl.org>
Thu, 13 Jun 2002 23:59:20 +0000
changeset 417 04ec6995f75d
parent 337 9154ec9ca3d2
child 769 b8d311d90021
permissions -rw-r--r--
*** empty log message ***
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  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  "@(#) $Id$";
    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 */