|
/*
|
|
Simple DirectMedia Layer
|
|
Copyright (C) 1997-2023 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"
|
|
|
|
/******************************************************************************/
|
|
/* Enable thread safety attributes only with clang.
|
|
* The attributes can be safely erased when compiling with other compilers.
|
|
*/
|
|
#if defined(SDL_THREAD_SAFETY_ANALYSIS) && \
|
|
defined(__clang__) && (!defined(SWIG))
|
|
#define SDL_THREAD_ANNOTATION_ATTRIBUTE__(x) __attribute__((x))
|
|
#else
|
|
#define SDL_THREAD_ANNOTATION_ATTRIBUTE__(x) /* no-op */
|
|
#endif
|
|
|
|
#define SDL_CAPABILITY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(capability(x))
|
|
|
|
#define SDL_SCOPED_CAPABILITY \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(scoped_lockable)
|
|
|
|
#define SDL_GUARDED_BY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(guarded_by(x))
|
|
|
|
#define SDL_PT_GUARDED_BY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(pt_guarded_by(x))
|
|
|
|
#define SDL_ACQUIRED_BEFORE(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(acquired_before(x))
|
|
|
|
#define SDL_ACQUIRED_AFTER(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(acquired_after(x))
|
|
|
|
#define SDL_REQUIRES(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(requires_capability(x))
|
|
|
|
#define SDL_REQUIRES_SHARED(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(requires_shared_capability(x))
|
|
|
|
#define SDL_ACQUIRE(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(acquire_capability(x))
|
|
|
|
#define SDL_ACQUIRE_SHARED(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(acquire_shared_capability(x))
|
|
|
|
#define SDL_RELEASE(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(release_capability(x))
|
|
|
|
#define SDL_RELEASE_SHARED(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(release_shared_capability(x))
|
|
|
|
#define SDL_RELEASE_GENERIC(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(release_generic_capability(x))
|
|
|
|
#define SDL_TRY_ACQUIRE(x, y) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_capability(x, y))
|
|
|
|
#define SDL_TRY_ACQUIRE_SHARED(x, y) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(try_acquire_shared_capability(x, y))
|
|
|
|
#define SDL_EXCLUDES(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(locks_excluded(x))
|
|
|
|
#define SDL_ASSERT_CAPABILITY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(assert_capability(x))
|
|
|
|
#define SDL_ASSERT_SHARED_CAPABILITY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(assert_shared_capability(x))
|
|
|
|
#define SDL_RETURN_CAPABILITY(x) \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(lock_returned(x))
|
|
|
|
#define SDL_NO_THREAD_SAFETY_ANALYSIS \
|
|
SDL_THREAD_ANNOTATION_ATTRIBUTE__(no_thread_safety_analysis)
|
|
|
|
/******************************************************************************/
|
|
|
|
|
|
#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 new mutex.
|
|
*
|
|
* All newly-created mutexes begin in the _unlocked_ state.
|
|
*
|
|
* Calls to SDL_LockMutex() will not return while the mutex is locked by
|
|
* another thread. See SDL_TryLockMutex() to attempt to lock without blocking.
|
|
*
|
|
* SDL mutexes are reentrant.
|
|
*
|
|
* \returns the initialized and unlocked mutex or NULL on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_DestroyMutex
|
|
* \sa SDL_LockMutex
|
|
* \sa SDL_TryLockMutex
|
|
* \sa SDL_UnlockMutex
|
|
*/
|
|
extern DECLSPEC SDL_mutex *SDLCALL SDL_CreateMutex(void);
|
|
|
|
/**
|
|
* Lock the mutex.
|
|
*
|
|
* This will block until the mutex is available, which is to say it is in the
|
|
* unlocked state and the OS has chosen the caller as the next thread to lock
|
|
* it. Of all threads waiting to lock the mutex, only one may do so at a time.
|
|
*
|
|
* It is legal for the owning thread to lock an already-locked mutex. It must
|
|
* unlock it the same number of times before it is actually made available for
|
|
* other threads in the system (this is known as a "recursive mutex").
|
|
*
|
|
* \param mutex the mutex to lock
|
|
* \return 0, or -1 on error.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_LockMutex(SDL_mutex * mutex) SDL_ACQUIRE(mutex);
|
|
#define SDL_mutexP(m) SDL_LockMutex(m)
|
|
|
|
/**
|
|
* Try to lock a mutex without blocking.
|
|
*
|
|
* This works just like SDL_LockMutex(), but if the mutex is not available,
|
|
* this function returns `SDL_MUTEX_TIMEOUT` immediately.
|
|
*
|
|
* This technique is useful if you need exclusive access to a resource but
|
|
* don't want to wait for it, and will return to it to try again later.
|
|
*
|
|
* \param mutex the mutex to try to lock
|
|
* \returns 0, `SDL_MUTEX_TIMEDOUT`, or -1 on error; call SDL_GetError() for
|
|
* more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateMutex
|
|
* \sa SDL_DestroyMutex
|
|
* \sa SDL_LockMutex
|
|
* \sa SDL_UnlockMutex
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_TryLockMutex(SDL_mutex * mutex) SDL_TRY_ACQUIRE(0, mutex);
|
|
|
|
/**
|
|
* Unlock the mutex.
|
|
*
|
|
* It is legal for the owning thread to lock an already-locked mutex. It must
|
|
* unlock it the same number of times before it is actually made available for
|
|
* other threads in the system (this is known as a "recursive mutex").
|
|
*
|
|
* It is an error to unlock a mutex that has not been locked by the current
|
|
* thread, and doing so results in undefined behavior.
|
|
*
|
|
* It is also an error to unlock a mutex that isn't locked at all.
|
|
*
|
|
* \param mutex the mutex to unlock.
|
|
* \returns 0, or -1 on error.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_UnlockMutex(SDL_mutex * mutex) SDL_RELEASE(mutex);
|
|
#define SDL_mutexV(m) SDL_UnlockMutex(m)
|
|
|
|
/**
|
|
* Destroy a mutex created with SDL_CreateMutex().
|
|
*
|
|
* This function must be called on any mutex that is no longer needed. Failure
|
|
* to destroy a mutex will result in a system memory or resource leak. While
|
|
* it is safe to destroy a mutex that is _unlocked_, it is not safe to attempt
|
|
* to destroy a locked mutex, and may result in undefined behavior depending
|
|
* on the platform.
|
|
*
|
|
* \param mutex the mutex to destroy
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateMutex
|
|
* \sa SDL_LockMutex
|
|
* \sa SDL_TryLockMutex
|
|
* \sa SDL_UnlockMutex
|
|
*/
|
|
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.
|
|
*
|
|
* This function creates a new semaphore and initializes it with the value
|
|
* `initial_value`. Each wait operation on the semaphore will atomically
|
|
* decrement the semaphore value and potentially block if the semaphore value
|
|
* is 0. Each post operation will atomically increment the semaphore value and
|
|
* wake waiting threads and allow them to retry the wait operation.
|
|
*
|
|
* \param initial_value the starting value of the semaphore
|
|
* \returns a new semaphore or NULL on failure; call SDL_GetError() for more
|
|
* information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_DestroySemaphore
|
|
* \sa SDL_SemPost
|
|
* \sa SDL_SemTryWait
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
* \sa SDL_SemWaitTimeout
|
|
*/
|
|
extern DECLSPEC SDL_sem *SDLCALL SDL_CreateSemaphore(Uint32 initial_value);
|
|
|
|
/**
|
|
* Destroy a semaphore.
|
|
*
|
|
* It is not safe to destroy a semaphore if there are threads currently
|
|
* waiting on it.
|
|
*
|
|
* \param sem the semaphore to destroy
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
* \sa SDL_SemPost
|
|
* \sa SDL_SemTryWait
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
* \sa SDL_SemWaitTimeout
|
|
*/
|
|
extern DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem * sem);
|
|
|
|
/**
|
|
* Wait until a semaphore has a positive value and then decrements it.
|
|
*
|
|
* This function suspends the calling thread until either the semaphore
|
|
* pointed to by `sem` has a positive value or the call is interrupted by a
|
|
* signal or error. If the call is successful it will atomically decrement the
|
|
* semaphore value.
|
|
*
|
|
* This function is the equivalent of calling SDL_SemWaitTimeout() with a time
|
|
* length of `SDL_MUTEX_MAXWAIT`.
|
|
*
|
|
* \param sem the semaphore wait on
|
|
* \returns 0 on success or a negative error code on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
* \sa SDL_DestroySemaphore
|
|
* \sa SDL_SemPost
|
|
* \sa SDL_SemTryWait
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
* \sa SDL_SemWaitTimeout
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_SemWait(SDL_sem * sem);
|
|
|
|
/**
|
|
* See if a semaphore has a positive value and decrement it if it does.
|
|
*
|
|
* This function checks to see if the semaphore pointed to by `sem` has a
|
|
* positive value and atomically decrements the semaphore value if it does. If
|
|
* the semaphore doesn't have a positive value, the function immediately
|
|
* returns SDL_MUTEX_TIMEDOUT.
|
|
*
|
|
* \param sem the semaphore to wait on
|
|
* \returns 0 if the wait succeeds, `SDL_MUTEX_TIMEDOUT` if the wait would
|
|
* block, or a negative error code on failure; call SDL_GetError()
|
|
* for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
* \sa SDL_DestroySemaphore
|
|
* \sa SDL_SemPost
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
* \sa SDL_SemWaitTimeout
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem * sem);
|
|
|
|
/**
|
|
* Wait until a semaphore has a positive value and then decrements it.
|
|
*
|
|
* This function suspends the calling thread until either the semaphore
|
|
* pointed to by `sem` has a positive value, the call is interrupted by a
|
|
* signal or error, or the specified time has elapsed. If the call is
|
|
* successful it will atomically decrement the semaphore value.
|
|
*
|
|
* \param sem the semaphore to wait on
|
|
* \param timeout the length of the timeout, in milliseconds
|
|
* \returns 0 if the wait succeeds, `SDL_MUTEX_TIMEDOUT` if the wait does not
|
|
* succeed in the allotted time, or a negative error code on failure;
|
|
* call SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
* \sa SDL_DestroySemaphore
|
|
* \sa SDL_SemPost
|
|
* \sa SDL_SemTryWait
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout);
|
|
|
|
/**
|
|
* Atomically increment a semaphore's value and wake waiting threads.
|
|
*
|
|
* \param sem the semaphore to increment
|
|
* \returns 0 on success or a negative error code on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
* \sa SDL_DestroySemaphore
|
|
* \sa SDL_SemTryWait
|
|
* \sa SDL_SemValue
|
|
* \sa SDL_SemWait
|
|
* \sa SDL_SemWaitTimeout
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_SemPost(SDL_sem * sem);
|
|
|
|
/**
|
|
* Get the current value of a semaphore.
|
|
*
|
|
* \param sem the semaphore to query
|
|
* \returns the current value of the semaphore.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CreateSemaphore
|
|
*/
|
|
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.
|
|
*
|
|
* \returns a new condition variable or NULL on failure; call SDL_GetError()
|
|
* for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondBroadcast
|
|
* \sa SDL_CondSignal
|
|
* \sa SDL_CondWait
|
|
* \sa SDL_CondWaitTimeout
|
|
* \sa SDL_DestroyCond
|
|
*/
|
|
extern DECLSPEC SDL_cond *SDLCALL SDL_CreateCond(void);
|
|
|
|
/**
|
|
* Destroy a condition variable.
|
|
*
|
|
* \param cond the condition variable to destroy
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondBroadcast
|
|
* \sa SDL_CondSignal
|
|
* \sa SDL_CondWait
|
|
* \sa SDL_CondWaitTimeout
|
|
* \sa SDL_CreateCond
|
|
*/
|
|
extern DECLSPEC void SDLCALL SDL_DestroyCond(SDL_cond * cond);
|
|
|
|
/**
|
|
* Restart one of the threads that are waiting on the condition variable.
|
|
*
|
|
* \param cond the condition variable to signal
|
|
* \returns 0 on success or a negative error code on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondBroadcast
|
|
* \sa SDL_CondWait
|
|
* \sa SDL_CondWaitTimeout
|
|
* \sa SDL_CreateCond
|
|
* \sa SDL_DestroyCond
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_CondSignal(SDL_cond * cond);
|
|
|
|
/**
|
|
* Restart all threads that are waiting on the condition variable.
|
|
*
|
|
* \param cond the condition variable to signal
|
|
* \returns 0 on success or a negative error code on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondSignal
|
|
* \sa SDL_CondWait
|
|
* \sa SDL_CondWaitTimeout
|
|
* \sa SDL_CreateCond
|
|
* \sa SDL_DestroyCond
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_CondBroadcast(SDL_cond * cond);
|
|
|
|
/**
|
|
* Wait until a condition variable is signaled.
|
|
*
|
|
* This function unlocks the specified `mutex` and waits for another thread to
|
|
* call SDL_CondSignal() or SDL_CondBroadcast() on the condition variable
|
|
* `cond`. Once the condition variable is signaled, the mutex is re-locked and
|
|
* the function returns.
|
|
*
|
|
* The mutex must be locked before calling this function.
|
|
*
|
|
* This function is the equivalent of calling SDL_CondWaitTimeout() with a
|
|
* time length of `SDL_MUTEX_MAXWAIT`.
|
|
*
|
|
* \param cond the condition variable to wait on
|
|
* \param mutex the mutex used to coordinate thread access
|
|
* \returns 0 when it is signaled or a negative error code on failure; call
|
|
* SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondBroadcast
|
|
* \sa SDL_CondSignal
|
|
* \sa SDL_CondWaitTimeout
|
|
* \sa SDL_CreateCond
|
|
* \sa SDL_DestroyCond
|
|
*/
|
|
extern DECLSPEC int SDLCALL SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex);
|
|
|
|
/**
|
|
* Wait until a condition variable is signaled or a certain time has passed.
|
|
*
|
|
* This function unlocks the specified `mutex` and waits for another thread to
|
|
* call SDL_CondSignal() or SDL_CondBroadcast() on the condition variable
|
|
* `cond`, or for the specified time to elapse. Once the condition variable is
|
|
* signaled or the time elapsed, the mutex is re-locked and the function
|
|
* returns.
|
|
*
|
|
* The mutex must be locked before calling this function.
|
|
*
|
|
* \param cond the condition variable to wait on
|
|
* \param mutex the mutex used to coordinate thread access
|
|
* \param ms the maximum time to wait, in milliseconds, or `SDL_MUTEX_MAXWAIT`
|
|
* to wait indefinitely
|
|
* \returns 0 if the condition variable is signaled, `SDL_MUTEX_TIMEDOUT` if
|
|
* the condition is not signaled in the allotted time, or a negative
|
|
* error code on failure; call SDL_GetError() for more information.
|
|
*
|
|
* \since This function is available since SDL 2.0.0.
|
|
*
|
|
* \sa SDL_CondBroadcast
|
|
* \sa SDL_CondSignal
|
|
* \sa SDL_CondWait
|
|
* \sa SDL_CreateCond
|
|
* \sa SDL_DestroyCond
|
|
*/
|
|
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: */
|