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SDL_mutex.h
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
#ifndef _SDL_mutex_h
#define _SDL_mutex_h
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/**
* \file SDL_mutex.h
*
* Functions to provide thread synchronization primitives
*/
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#include "SDL_stdinc.h"
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#include "SDL_error.h"
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#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
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/* *INDENT-OFF* */
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extern "C" {
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/* *INDENT-ON* */
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#endif
/* Synchronization functions which can time out return this value
if they time out.
*/
#define SDL_MUTEX_TIMEDOUT 1
/* This is the timeout value which corresponds to never time out */
#define SDL_MUTEX_MAXWAIT (~(Uint32)0)
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* Mutex functions */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* The SDL mutex structure, defined in SDL_mutex.c */
struct SDL_mutex;
typedef struct SDL_mutex SDL_mutex;
/* Create a mutex, initialized unlocked */
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extern DECLSPEC SDL_mutex *SDLCALL SDL_CreateMutex(void);
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/* Lock the mutex (Returns 0, or -1 on error) */
#define SDL_LockMutex(m) SDL_mutexP(m)
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extern DECLSPEC int SDLCALL SDL_mutexP(SDL_mutex * mutex);
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/* Unlock the mutex (Returns 0, or -1 on error)
It is an error to unlock a mutex that has not been locked by
the current thread, and doing so results in undefined behavior.
*/
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#define SDL_UnlockMutex(m) SDL_mutexV(m)
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extern DECLSPEC int SDLCALL SDL_mutexV(SDL_mutex * mutex);
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/* Destroy a mutex */
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extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex * mutex);
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* Semaphore functions */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* The SDL semaphore structure, defined in SDL_sem.c */
struct SDL_semaphore;
typedef struct SDL_semaphore SDL_sem;
/* Create a semaphore, initialized with value, returns NULL on failure. */
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extern DECLSPEC SDL_sem *SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
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/* Destroy a semaphore */
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extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem * sem);
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/* This function suspends the calling thread until the semaphore pointed
* to by sem has a positive count. It then atomically decreases the semaphore
* count.
*/
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extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem * sem);
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/* Non-blocking variant of SDL_SemWait(), returns 0 if the wait succeeds,
SDL_MUTEX_TIMEDOUT if the wait would block, and -1 on error.
*/
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extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem * sem);
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/* Variant of SDL_SemWait() with a timeout in milliseconds, returns 0 if
the wait succeeds, SDL_MUTEX_TIMEDOUT if the wait does not succeed in
the allotted time, and -1 on error.
On some platforms this function is implemented by looping with a delay
of 1 ms, and so should be avoided if possible.
*/
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extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem * sem, Uint32 ms);
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/* Atomically increases the semaphore's count (not blocking), returns 0,
or -1 on error.
*/
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extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem * sem);
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/* Returns the current count of the semaphore */
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extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem * sem);
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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* Condition variable functions */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* The SDL condition variable structure, defined in SDL_cond.c */
struct SDL_cond;
typedef struct SDL_cond SDL_cond;
/* Create a condition variable */
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extern DECLSPEC SDL_cond *SDLCALL SDL_CreateCond(void);
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/* Destroy a condition variable */
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extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond * cond);
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/* Restart one of the threads that are waiting on the condition variable,
returns 0 or -1 on error.
*/
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extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond * cond);
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/* Restart all threads that are waiting on the condition variable,
returns 0 or -1 on error.
*/
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extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond * cond);
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/* Wait on the condition variable, unlocking the provided mutex.
The mutex must be locked before entering this function!
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The mutex is re-locked once the condition variable is signaled.
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Returns 0 when it is signaled, or -1 on error.
*/
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extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond * cond, SDL_mutex * mut);
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/* Waits for at most 'ms' milliseconds, and returns 0 if the condition
variable is signaled, SDL_MUTEX_TIMEDOUT if the condition is not
signaled in the allotted time, and -1 on error.
On some platforms this function is implemented by looping with a delay
of 1 ms, and so should be avoided if possible.
*/
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extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond * cond,
SDL_mutex * mutex, Uint32 ms);
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/* Ends C function definitions when using C++ */
#ifdef __cplusplus
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/* *INDENT-OFF* */
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}
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/* *INDENT-ON* */
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#endif
#include "close_code.h"
#endif /* _SDL_mutex_h */
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/* vi: set ts=4 sw=4 expandtab: */