include/SDL_mutex.h
author Sam Lantinga <slouken@libsdl.org>
Thu, 11 Apr 2002 14:35:16 +0000
changeset 337 9154ec9ca3d2
parent 297 f6ffac90895c
child 417 04ec6995f75d
permissions -rw-r--r--
Explicitly specify the SDL API calling convention (C by default)
     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 #define SDL_UnlockMutex(m)	SDL_mutexV(m)
    71 extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex *mutex);
    72 
    73 /* Destroy a mutex */
    74 extern DECLSPEC void SDLCALL 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 * SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
    87 
    88 /* Destroy a semaphore */
    89 extern DECLSPEC void SDLCALL 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 SDLCALL 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 SDLCALL 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 SDLCALL 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 SDLCALL SDL_SemPost(SDL_sem *sem);
   114 
   115 /* Returns the current count of the semaphore */
   116 extern DECLSPEC Uint32 SDLCALL 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 * SDLCALL SDL_CreateCond(void);
   129 
   130 /* Destroy a condition variable */
   131 extern DECLSPEC void SDLCALL 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 SDLCALL 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 SDLCALL 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 SDLCALL 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 SDLCALL 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 */