Diff: SDL_thread.h

Revision:

0:dda4f4550403

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SDL_thread.h	Wed Sep 07 18:46:53 2016 +0000
@@ -0,0 +1,287 @@
+/*
+  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_thread_h
+#define _SDL_thread_h
+
+/**
+ *  \file SDL_thread.h
+ *
+ *  Header for the SDL thread management routines.
+ */
+
+#include "SDL_stdinc.h"
+#include "SDL_error.h"
+
+/* Thread synchronization primitives */
+#include "SDL_atomic.h"
+#include "SDL_mutex.h"
+
+#include "begin_code.h"
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The SDL thread structure, defined in SDL_thread.c */
+struct SDL_Thread;
+typedef struct SDL_Thread SDL_Thread;
+
+/* The SDL thread ID */
+typedef unsigned long SDL_threadID;
+
+/* Thread local storage ID, 0 is the invalid ID */
+typedef unsigned int SDL_TLSID;
+
+/**
+ *  The SDL thread priority.
+ *
+ *  \note On many systems you require special privileges to set high priority.
+ */
+typedef enum {
+    SDL_THREAD_PRIORITY_LOW,
+    SDL_THREAD_PRIORITY_NORMAL,
+    SDL_THREAD_PRIORITY_HIGH
+} SDL_ThreadPriority;
+
+/**
+ *  The function passed to SDL_CreateThread().
+ *  It is passed a void* user context parameter and returns an int.
+ */
+typedef int (SDLCALL * SDL_ThreadFunction) (void *data);
+
+#if defined(__WIN32__) && !defined(HAVE_LIBC)
+/**
+ *  \file SDL_thread.h
+ *
+ *  We compile SDL into a DLL. This means, that it's the DLL which
+ *  creates a new thread for the calling process with the SDL_CreateThread()
+ *  API. There is a problem with this, that only the RTL of the SDL.DLL will
+ *  be initialized for those threads, and not the RTL of the calling
+ *  application!
+ *
+ *  To solve this, we make a little hack here.
+ *
+ *  We'll always use the caller's _beginthread() and _endthread() APIs to
+ *  start a new thread. This way, if it's the SDL.DLL which uses this API,
+ *  then the RTL of SDL.DLL will be used to create the new thread, and if it's
+ *  the application, then the RTL of the application will be used.
+ *
+ *  So, in short:
+ *  Always use the _beginthread() and _endthread() of the calling runtime
+ *  library!
+ */
+#define SDL_PASSED_BEGINTHREAD_ENDTHREAD
+#include <process.h>            /* This has _beginthread() and _endthread() defined! */
+
+typedef uintptr_t(__cdecl * pfnSDL_CurrentBeginThread) (void *, unsigned,
+                                                        unsigned (__stdcall *
+                                                                  func) (void
+                                                                         *),
+                                                        void *arg, unsigned,
+                                                        unsigned *threadID);
+typedef void (__cdecl * pfnSDL_CurrentEndThread) (unsigned code);
+
+/**
+ *  Create a thread.
+ */
+extern DECLSPEC SDL_Thread *SDLCALL
+SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data,
+                 pfnSDL_CurrentBeginThread pfnBeginThread,
+                 pfnSDL_CurrentEndThread pfnEndThread);
+
+/**
+ *  Create a thread.
+ */
+#if defined(SDL_CreateThread) && SDL_DYNAMIC_API
+#undef SDL_CreateThread
+#define SDL_CreateThread(fn, name, data) SDL_CreateThread_REAL(fn, name, data, (pfnSDL_CurrentBeginThread)_beginthreadex, (pfnSDL_CurrentEndThread)_endthreadex)
+#else
+#define SDL_CreateThread(fn, name, data) SDL_CreateThread(fn, name, data, (pfnSDL_CurrentBeginThread)_beginthreadex, (pfnSDL_CurrentEndThread)_endthreadex)
+#endif
+
+#else
+
+/**
+ *  Create a thread.
+ *
+ *   Thread naming is a little complicated: Most systems have very small
+ *    limits for the string length (Haiku has 32 bytes, Linux currently has 16,
+ *    Visual C++ 6.0 has nine!), and possibly other arbitrary rules. You'll
+ *    have to see what happens with your system's debugger. The name should be
+ *    UTF-8 (but using the naming limits of C identifiers is a better bet).
+ *   There are no requirements for thread naming conventions, so long as the
+ *    string is null-terminated UTF-8, but these guidelines are helpful in
+ *    choosing a name:
+ *
+ *    http://stackoverflow.com/questions/149932/naming-conventions-for-threads
+ *
+ *   If a system imposes requirements, SDL will try to munge the string for
+ *    it (truncate, etc), but the original string contents will be available
+ *    from SDL_GetThreadName().
+ */
+extern DECLSPEC SDL_Thread *SDLCALL
+SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data);
+
+#endif
+
+/**
+ * Get the thread name, as it was specified in SDL_CreateThread().
+ *  This function returns a pointer to a UTF-8 string that names the
+ *  specified thread, or NULL if it doesn't have a name. This is internal
+ *  memory, not to be free()'d by the caller, and remains valid until the
+ *  specified thread is cleaned up by SDL_WaitThread().
+ */
+extern DECLSPEC const char *SDLCALL SDL_GetThreadName(SDL_Thread *thread);
+
+/**
+ *  Get the thread identifier for the current thread.
+ */
+extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
+
+/**
+ *  Get the thread identifier for the specified thread.
+ *
+ *  Equivalent to SDL_ThreadID() if the specified thread is NULL.
+ */
+extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
+
+/**
+ *  Set the priority for the current thread
+ */
+extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_ThreadPriority priority);
+
+/**
+ *  Wait for a thread to finish. Threads that haven't been detached will
+ *  remain (as a "zombie") until this function cleans them up. Not doing so
+ *  is a resource leak.
+ *
+ *  Once a thread has been cleaned up through this function, the SDL_Thread
+ *  that references it becomes invalid and should not be referenced again.
+ *  As such, only one thread may call SDL_WaitThread() on another.
+ *
+ *  The return code for the thread function is placed in the area
+ *  pointed to by \c status, if \c status is not NULL.
+ *
+ *  You may not wait on a thread that has been used in a call to
+ *  SDL_DetachThread(). Use either that function or this one, but not
+ *  both, or behavior is undefined.
+ *
+ *  It is safe to pass NULL to this function; it is a no-op.
+ */
+extern DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread * thread, int *status);
+
+/**
+ *  A thread may be "detached" to signify that it should not remain until
+ *  another thread has called SDL_WaitThread() on it. Detaching a thread
+ *  is useful for long-running threads that nothing needs to synchronize
+ *  with or further manage. When a detached thread is done, it simply
+ *  goes away.
+ *
+ *  There is no way to recover the return code of a detached thread. If you
+ *  need this, don't detach the thread and instead use SDL_WaitThread().
+ *
+ *  Once a thread is detached, you should usually assume the SDL_Thread isn't
+ *  safe to reference again, as it will become invalid immediately upon
+ *  the detached thread's exit, instead of remaining until someone has called
+ *  SDL_WaitThread() to finally clean it up. As such, don't detach the same
+ *  thread more than once.
+ *
+ *  If a thread has already exited when passed to SDL_DetachThread(), it will
+ *  stop waiting for a call to SDL_WaitThread() and clean up immediately.
+ *  It is not safe to detach a thread that might be used with SDL_WaitThread().
+ *
+ *  You may not call SDL_WaitThread() on a thread that has been detached.
+ *  Use either that function or this one, but not both, or behavior is
+ *  undefined.
+ *
+ *  It is safe to pass NULL to this function; it is a no-op.
+ */
+extern DECLSPEC void SDLCALL SDL_DetachThread(SDL_Thread * thread);
+
+/**
+ *  \brief Create an identifier that is globally visible to all threads but refers to data that is thread-specific.
+ *
+ *  \return The newly created thread local storage identifier, or 0 on error
+ *
+ *  \code
+ *  static SDL_SpinLock tls_lock;
+ *  static SDL_TLSID thread_local_storage;
+ * 
+ *  void SetMyThreadData(void *value)
+ *  {
+ *      if (!thread_local_storage) {
+ *          SDL_AtomicLock(&tls_lock);
+ *          if (!thread_local_storage) {
+ *              thread_local_storage = SDL_TLSCreate();
+ *          }
+ *          SDL_AtomicUnLock(&tls_lock);
+ *      }
+ *      SDL_TLSSet(thread_local_storage, value);
+ *  }
+ *  
+ *  void *GetMyThreadData(void)
+ *  {
+ *      return SDL_TLSGet(thread_local_storage);
+ *  }
+ *  \endcode
+ *
+ *  \sa SDL_TLSGet()
+ *  \sa SDL_TLSSet()
+ */
+extern DECLSPEC SDL_TLSID SDLCALL SDL_TLSCreate(void);
+
+/**
+ *  \brief Get the value associated with a thread local storage ID for the current thread.
+ *
+ *  \param id The thread local storage ID
+ *
+ *  \return The value associated with the ID for the current thread, or NULL if no value has been set.
+ *
+ *  \sa SDL_TLSCreate()
+ *  \sa SDL_TLSSet()
+ */
+extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
+
+/**
+ *  \brief Set the value associated with a thread local storage ID for the current thread.
+ *
+ *  \param id The thread local storage ID
+ *  \param value The value to associate with the ID for the current thread
+ *  \param destructor A function called when the thread exits, to free the value.
+ *
+ *  \return 0 on success, -1 on error
+ *
+ *  \sa SDL_TLSCreate()
+ *  \sa SDL_TLSGet()
+ */
+extern DECLSPEC int SDLCALL SDL_TLSSet(SDL_TLSID id, const void *value, void (*destructor)(void*));
+
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include "close_code.h"
+
+#endif /* _SDL_thread_h */
+
+/* vi: set ts=4 sw=4 expandtab: */