--- /dev/null
+/*
+ Simple DirectMedia Layer
+ Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
+
+ This software is provided 'as-is', without any express or implied
+ warranty. In no event will the authors be held liable for any damages
+ arising from the use of this software.
+
+ Permission is granted to anyone to use this software for any purpose,
+ including commercial applications, and to alter it and redistribute it
+ freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+ 3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef _SDL_mutex_h
+#define _SDL_mutex_h
+
+/**
+ * \file SDL_mutex.h
+ *
+ * Functions to provide thread synchronization primitives.
+ */
+
+#include "SDL_stdinc.h"
+#include "SDL_error.h"
+
+#include "begin_code.h"
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#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)
+
+
+/**
+ * \name Mutex functions
+ */
+/* @{ */
+
+/* The SDL mutex structure, defined in SDL_sysmutex.c */
+struct SDL_mutex;
+typedef struct SDL_mutex SDL_mutex;
+
+/**
+ * Create a mutex, initialized unlocked.
+ */
+extern DECLSPEC SDL_mutex *SDLCALL SDL_CreateMutex(void);
+
+/**
+ * Lock the mutex.
+ *
+ * \return 0, or -1 on error.
+ */
+#define SDL_mutexP(m) SDL_LockMutex(m)
+extern DECLSPEC int SDLCALL SDL_LockMutex(SDL_mutex * mutex);
+
+/**
+ * Try to lock the mutex
+ *
+ * \return 0, SDL_MUTEX_TIMEDOUT, or -1 on error
+ */
+extern DECLSPEC int SDLCALL SDL_TryLockMutex(SDL_mutex * mutex);
+
+/**
+ * Unlock the mutex.
+ *
+ * \return 0, or -1 on error.
+ *
+ * \warning It is an error to unlock a mutex that has not been locked by
+ * the current thread, and doing so results in undefined behavior.
+ */
+#define SDL_mutexV(m) SDL_UnlockMutex(m)
+extern DECLSPEC int SDLCALL SDL_UnlockMutex(SDL_mutex * mutex);
+
+/**
+ * Destroy a mutex.
+ */
+extern DECLSPEC void SDLCALL SDL_DestroyMutex(SDL_mutex * mutex);
+
+/* @} *//* Mutex functions */
+
+
+/**
+ * \name Semaphore functions
+ */
+/* @{ */
+
+/* The SDL semaphore structure, defined in SDL_syssem.c */
+struct SDL_semaphore;
+typedef struct SDL_semaphore SDL_sem;
+
+/**
+ * Create a semaphore, initialized with value, returns NULL on failure.
+ */
+extern DECLSPEC SDL_sem *SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
+
+/**
+ * Destroy a semaphore.
+ */
+extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem * sem);
+
+/**
+ * This function suspends the calling thread until the semaphore pointed
+ * to by \c sem has a positive count. It then atomically decreases the
+ * semaphore count.
+ */
+extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem * sem);
+
+/**
+ * Non-blocking variant of SDL_SemWait().
+ *
+ * \return 0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait would
+ * block, and -1 on error.
+ */
+extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem * sem);
+
+/**
+ * Variant of SDL_SemWait() with a timeout in milliseconds.
+ *
+ * \return 0 if the wait succeeds, ::SDL_MUTEX_TIMEDOUT if the wait does not
+ * succeed in the allotted time, and -1 on error.
+ *
+ * \warning On some platforms this function is implemented by looping with a
+ * delay of 1 ms, and so should be avoided if possible.
+ */
+extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem * sem, Uint32 ms);
+
+/**
+ * Atomically increases the semaphore's count (not blocking).
+ *
+ * \return 0, or -1 on error.
+ */
+extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem * sem);
+
+/**
+ * Returns the current count of the semaphore.
+ */
+extern DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem * sem);
+
+/* @} *//* Semaphore functions */
+
+
+/**
+ * \name Condition variable functions
+ */
+/* @{ */
+
+/* The SDL condition variable structure, defined in SDL_syscond.c */
+struct SDL_cond;
+typedef struct SDL_cond SDL_cond;
+
+/**
+ * Create a condition variable.
+ *
+ * Typical use of condition variables:
+ *
+ * Thread A:
+ * SDL_LockMutex(lock);
+ * while ( ! condition ) {
+ * SDL_CondWait(cond, lock);
+ * }
+ * SDL_UnlockMutex(lock);
+ *
+ * Thread B:
+ * SDL_LockMutex(lock);
+ * ...
+ * condition = true;
+ * ...
+ * SDL_CondSignal(cond);
+ * SDL_UnlockMutex(lock);
+ *
+ * There is some discussion whether to signal the condition variable
+ * with the mutex locked or not. There is some potential performance
+ * benefit to unlocking first on some platforms, but there are some
+ * potential race conditions depending on how your code is structured.
+ *
+ * In general it's safer to signal the condition variable while the
+ * mutex is locked.
+ */
+extern DECLSPEC SDL_cond *SDLCALL SDL_CreateCond(void);
+
+/**
+ * Destroy a condition variable.
+ */
+extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond * cond);
+
+/**
+ * Restart one of the threads that are waiting on the condition variable.
+ *
+ * \return 0 or -1 on error.
+ */
+extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond * cond);
+
+/**
+ * Restart all threads that are waiting on the condition variable.
+ *
+ * \return 0 or -1 on error.
+ */
+extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond * cond);
+
+/**
+ * Wait on the condition variable, unlocking the provided mutex.
+ *
+ * \warning The mutex must be locked before entering this function!
+ *
+ * The mutex is re-locked once the condition variable is signaled.
+ *
+ * \return 0 when it is signaled, or -1 on error.
+ */
+extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex);
+
+/**
+ * Waits for at most \c 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.
+ *
+ * \warning On some platforms this function is implemented by looping with a
+ * delay of 1 ms, and so should be avoided if possible.
+ */
+extern DECLSPEC int SDLCALL SDL_CondWaitTimeout(SDL_cond * cond,
+ SDL_mutex * mutex, Uint32 ms);
+
+/* @} *//* Condition variable functions */
+
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include "close_code.h"
+
+#endif /* _SDL_mutex_h */
+
+/* vi: set ts=4 sw=4 expandtab: */
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