288 lines
9.9 KiB
C
288 lines
9.9 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef _SDL_thread_h
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#define _SDL_thread_h
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/**
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* \file SDL_thread.h
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*
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* Header for the SDL thread management routines.
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*/
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#include "SDL_stdinc.h"
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#include "SDL_error.h"
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/* Thread synchronization primitives */
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#include "SDL_atomic.h"
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#include "SDL_mutex.h"
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#include "begin_code.h"
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* The SDL thread structure, defined in SDL_thread.c */
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struct SDL_Thread;
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typedef struct SDL_Thread SDL_Thread;
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/* The SDL thread ID */
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typedef unsigned long SDL_threadID;
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/* Thread local storage ID, 0 is the invalid ID */
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typedef unsigned int SDL_TLSID;
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/**
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* The SDL thread priority.
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*
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* \note On many systems you require special privileges to set high priority.
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*/
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typedef enum {
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SDL_THREAD_PRIORITY_LOW,
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SDL_THREAD_PRIORITY_NORMAL,
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SDL_THREAD_PRIORITY_HIGH
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} SDL_ThreadPriority;
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/**
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* The function passed to SDL_CreateThread().
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* It is passed a void* user context parameter and returns an int.
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*/
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typedef int (SDLCALL * SDL_ThreadFunction) (void *data);
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#if defined(__WIN32__) && !defined(HAVE_LIBC)
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/**
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* \file SDL_thread.h
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*
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* We compile SDL into a DLL. This means, that it's the DLL which
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* creates a new thread for the calling process with the SDL_CreateThread()
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* API. There is a problem with this, that only the RTL of the SDL.DLL will
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* be initialized for those threads, and not the RTL of the calling
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* application!
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*
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* To solve this, we make a little hack here.
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*
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* We'll always use the caller's _beginthread() and _endthread() APIs to
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* start a new thread. This way, if it's the SDL.DLL which uses this API,
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* then the RTL of SDL.DLL will be used to create the new thread, and if it's
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* the application, then the RTL of the application will be used.
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*
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* So, in short:
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* Always use the _beginthread() and _endthread() of the calling runtime
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* library!
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*/
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#define SDL_PASSED_BEGINTHREAD_ENDTHREAD
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#include <process.h> /* This has _beginthread() and _endthread() defined! */
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typedef uintptr_t(__cdecl * pfnSDL_CurrentBeginThread) (void *, unsigned,
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unsigned (__stdcall *
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func) (void
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*),
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void *arg, unsigned,
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unsigned *threadID);
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typedef void (__cdecl * pfnSDL_CurrentEndThread) (unsigned code);
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/**
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* Create a thread.
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*/
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extern DECLSPEC SDL_Thread *SDLCALL
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SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data,
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pfnSDL_CurrentBeginThread pfnBeginThread,
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pfnSDL_CurrentEndThread pfnEndThread);
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/**
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* Create a thread.
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*/
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#if defined(SDL_CreateThread) && SDL_DYNAMIC_API
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#undef SDL_CreateThread
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#define SDL_CreateThread(fn, name, data) SDL_CreateThread_REAL(fn, name, data, (pfnSDL_CurrentBeginThread)_beginthreadex, (pfnSDL_CurrentEndThread)_endthreadex)
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#else
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#define SDL_CreateThread(fn, name, data) SDL_CreateThread(fn, name, data, (pfnSDL_CurrentBeginThread)_beginthreadex, (pfnSDL_CurrentEndThread)_endthreadex)
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#endif
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#else
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/**
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* Create a thread.
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*
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* Thread naming is a little complicated: Most systems have very small
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* limits for the string length (Haiku has 32 bytes, Linux currently has 16,
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* Visual C++ 6.0 has nine!), and possibly other arbitrary rules. You'll
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* have to see what happens with your system's debugger. The name should be
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* UTF-8 (but using the naming limits of C identifiers is a better bet).
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* There are no requirements for thread naming conventions, so long as the
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* string is null-terminated UTF-8, but these guidelines are helpful in
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* choosing a name:
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*
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* http://stackoverflow.com/questions/149932/naming-conventions-for-threads
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*
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* If a system imposes requirements, SDL will try to munge the string for
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* it (truncate, etc), but the original string contents will be available
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* from SDL_GetThreadName().
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*/
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extern DECLSPEC SDL_Thread *SDLCALL
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SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data);
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#endif
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/**
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* Get the thread name, as it was specified in SDL_CreateThread().
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* This function returns a pointer to a UTF-8 string that names the
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* specified thread, or NULL if it doesn't have a name. This is internal
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* memory, not to be free()'d by the caller, and remains valid until the
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* specified thread is cleaned up by SDL_WaitThread().
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*/
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extern DECLSPEC const char *SDLCALL SDL_GetThreadName(SDL_Thread *thread);
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/**
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* Get the thread identifier for the current thread.
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*/
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extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
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/**
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* Get the thread identifier for the specified thread.
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*
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* Equivalent to SDL_ThreadID() if the specified thread is NULL.
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*/
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extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
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/**
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* Set the priority for the current thread
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*/
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extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_ThreadPriority priority);
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/**
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* Wait for a thread to finish. Threads that haven't been detached will
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* remain (as a "zombie") until this function cleans them up. Not doing so
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* is a resource leak.
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*
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* Once a thread has been cleaned up through this function, the SDL_Thread
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* that references it becomes invalid and should not be referenced again.
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* As such, only one thread may call SDL_WaitThread() on another.
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*
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* The return code for the thread function is placed in the area
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* pointed to by \c status, if \c status is not NULL.
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*
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* You may not wait on a thread that has been used in a call to
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* SDL_DetachThread(). Use either that function or this one, but not
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* both, or behavior is undefined.
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*
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* It is safe to pass NULL to this function; it is a no-op.
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*/
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extern DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread * thread, int *status);
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/**
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* A thread may be "detached" to signify that it should not remain until
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* another thread has called SDL_WaitThread() on it. Detaching a thread
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* is useful for long-running threads that nothing needs to synchronize
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* with or further manage. When a detached thread is done, it simply
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* goes away.
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*
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* There is no way to recover the return code of a detached thread. If you
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* need this, don't detach the thread and instead use SDL_WaitThread().
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*
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* Once a thread is detached, you should usually assume the SDL_Thread isn't
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* safe to reference again, as it will become invalid immediately upon
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* the detached thread's exit, instead of remaining until someone has called
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* SDL_WaitThread() to finally clean it up. As such, don't detach the same
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* thread more than once.
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*
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* If a thread has already exited when passed to SDL_DetachThread(), it will
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* stop waiting for a call to SDL_WaitThread() and clean up immediately.
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* It is not safe to detach a thread that might be used with SDL_WaitThread().
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*
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* You may not call SDL_WaitThread() on a thread that has been detached.
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* Use either that function or this one, but not both, or behavior is
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* undefined.
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*
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* It is safe to pass NULL to this function; it is a no-op.
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*/
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extern DECLSPEC void SDLCALL SDL_DetachThread(SDL_Thread * thread);
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/**
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* \brief Create an identifier that is globally visible to all threads but refers to data that is thread-specific.
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*
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* \return The newly created thread local storage identifier, or 0 on error
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*
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* \code
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* static SDL_SpinLock tls_lock;
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* static SDL_TLSID thread_local_storage;
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*
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* void SetMyThreadData(void *value)
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* {
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* if (!thread_local_storage) {
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* SDL_AtomicLock(&tls_lock);
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* if (!thread_local_storage) {
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* thread_local_storage = SDL_TLSCreate();
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* }
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* SDL_AtomicUnlock(&tls_lock);
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* }
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* SDL_TLSSet(thread_local_storage, value, 0);
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* }
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*
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* void *GetMyThreadData(void)
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* {
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* return SDL_TLSGet(thread_local_storage);
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* }
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* \endcode
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*
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* \sa SDL_TLSGet()
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* \sa SDL_TLSSet()
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*/
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extern DECLSPEC SDL_TLSID SDLCALL SDL_TLSCreate(void);
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/**
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* \brief Get the value associated with a thread local storage ID for the current thread.
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*
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* \param id The thread local storage ID
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*
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* \return The value associated with the ID for the current thread, or NULL if no value has been set.
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*
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* \sa SDL_TLSCreate()
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* \sa SDL_TLSSet()
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*/
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extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
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/**
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* \brief Set the value associated with a thread local storage ID for the current thread.
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*
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* \param id The thread local storage ID
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* \param value The value to associate with the ID for the current thread
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* \param destructor A function called when the thread exits, to free the value.
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*
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* \return 0 on success, -1 on error
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*
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* \sa SDL_TLSCreate()
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* \sa SDL_TLSGet()
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*/
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extern DECLSPEC int SDLCALL SDL_TLSSet(SDL_TLSID id, const void *value, void (*destructor)(void*));
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#include "close_code.h"
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#endif /* _SDL_thread_h */
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/* vi: set ts=4 sw=4 expandtab: */
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