include/SDL_mutex.h
author Sam Lantinga <slouken@libsdl.org>
Sat, 26 Sep 2009 23:17:08 +0000
branchSDL-1.2
changeset 4246 8b8314cc34a6
parent 4217 4c4113c2162c
child 6137 4720145f848b
permissions -rw-r--r--
Fixed bug #810

Lauri Kenttä 2009-09-26 06:42:23 PDT

Support for disabling stdio redirect with environment variables.
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2009 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 /** @file SDL_mutex.h
    27  *  Functions to provide thread synchronization primitives
    28  *
    29  *  @note These are independent of the other SDL routines.
    30  */
    31 
    32 #include "SDL_stdinc.h"
    33 #include "SDL_error.h"
    34 
    35 #include "begin_code.h"
    36 /* Set up for C function definitions, even when using C++ */
    37 #ifdef __cplusplus
    38 extern "C" {
    39 #endif
    40 
    41 /** Synchronization functions which can time out return this value
    42  *  if they time out.
    43  */
    44 #define SDL_MUTEX_TIMEDOUT	1
    45 
    46 /** This is the timeout value which corresponds to never time out */
    47 #define SDL_MUTEX_MAXWAIT	(~(Uint32)0)
    48 
    49 
    50 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
    51 /** @name Mutex functions                                        */ /*@{*/
    52 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
    53 
    54 /** The SDL mutex structure, defined in SDL_mutex.c */
    55 struct SDL_mutex;
    56 typedef struct SDL_mutex SDL_mutex;
    57 
    58 /** Create a mutex, initialized unlocked */
    59 extern DECLSPEC SDL_mutex * SDLCALL SDL_CreateMutex(void);
    60 
    61 #define SDL_LockMutex(m)	SDL_mutexP(m)
    62 /** Lock the mutex
    63  *  @return 0, or -1 on error
    64  */
    65 extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex *mutex);
    66 
    67 #define SDL_UnlockMutex(m)	SDL_mutexV(m)
    68 /** Unlock the mutex
    69  *  @return 0, or -1 on error
    70  *
    71  *  It is an error to unlock a mutex that has not been locked by
    72  *  the current thread, and doing so results in undefined behavior.
    73  */
    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 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
    82 /** @name Semaphore functions                                    */ /*@{*/
    83 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
    84 
    85 /** The SDL semaphore structure, defined in SDL_sem.c */
    86 struct SDL_semaphore;
    87 typedef struct SDL_semaphore SDL_sem;
    88 
    89 /** Create a semaphore, initialized with value, returns NULL on failure. */
    90 extern DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
    91 
    92 /** Destroy a semaphore */
    93 extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem);
    94 
    95 /**
    96  * This function suspends the calling thread until the semaphore pointed 
    97  * to by sem has a positive count. It then atomically decreases the semaphore
    98  * count.
    99  */
   100 extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem);
   101 
   102 /** Non-blocking variant of SDL_SemWait().
   103  *  @return 0 if the wait succeeds,
   104  *  SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.
   105  */
   106 extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem);
   107 
   108 /** Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if
   109  *  the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in
   110  *  the allotted time, and -1 on error.
   111  *
   112  *  On some platforms this function is implemented by looping with a delay
   113  *  of 1 ms, and so should be avoided if possible.
   114  */
   115 extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 ms);
   116 
   117 /** Atomically increases the semaphore's count (not blocking).
   118  *  @return 0, or -1 on error.
   119  */
   120 extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem);
   121 
   122 /** Returns the current count of the semaphore */
   123 extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem);
   124 
   125 /*@}*/
   126 
   127 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
   128 /** @name Condition_variable_functions                           */ /*@{*/
   129 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
   130 
   131 /*@{*/
   132 /** The SDL condition variable structure, defined in SDL_cond.c */
   133 struct SDL_cond;
   134 typedef struct SDL_cond SDL_cond;
   135 /*@}*/
   136 
   137 /** Create a condition variable */
   138 extern DECLSPEC SDL_cond * SDLCALL SDL_CreateCond(void);
   139 
   140 /** Destroy a condition variable */
   141 extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond *cond);
   142 
   143 /** Restart one of the threads that are waiting on the condition variable,
   144  *  @return 0 or -1 on error.
   145  */
   146 extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond *cond);
   147 
   148 /** Restart all threads that are waiting on the condition variable,
   149  *  @return 0 or -1 on error.
   150  */
   151 extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond *cond);
   152 
   153 /** Wait on the condition variable, unlocking the provided mutex.
   154  *  The mutex must be locked before entering this function!
   155  *  The mutex is re-locked once the condition variable is signaled.
   156  *  @return 0 when it is signaled, or -1 on error.
   157  */
   158 extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond *cond, SDL_mutex *mut);
   159 
   160 /** Waits for at most 'ms' milliseconds, and returns 0 if the condition
   161  *  variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not
   162  *  signaled in the allotted time, and -1 on error.
   163  *  On some platforms this function is implemented by looping with a delay
   164  *  of 1 ms, and so should be avoided if possible.
   165  */
   166 extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms);
   167 
   168 /*@}*/
   169 
   170 /* Ends C function definitions when using C++ */
   171 #ifdef __cplusplus
   172 }
   173 #endif
   174 #include "close_code.h"
   175 
   176 #endif /* _SDL_mutex_h */
   177