foo_out_sdl: SDL3/SDL_thread.h comparison

comparison SDL3/SDL_thread.h @ 1:20d02a178406 default tip

*: check in everything else yay

author	Paper <paper@tflc.us>
date	Mon, 05 Jan 2026 02:15:46 -0500
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-:e9bb126753e7
+:20d02a178406
+/*
+Simple DirectMedia Layer
+Copyright (C) 1997-2025 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_
+/**
+* # CategoryThread
+*
+* SDL offers cross-platform thread management functions. These are mostly
+* concerned with starting threads, setting their priority, and dealing with
+* their termination.
+*
+* In addition, there is support for Thread Local Storage (data that is unique
+* to each thread, but accessed from a single key).
+*
+* On platforms without thread support (such as Emscripten when built without
+* pthreads), these functions still exist, but things like SDL_CreateThread()
+* will report failure without doing anything.
+*
+* If you're going to work with threads, you almost certainly need to have a
+* good understanding of thread safety measures: locking and synchronization
+* mechanisms are handled by the functions in SDL_mutex.h.
+*/
+#include <SDL3/SDL_stdinc.h>
+#include <SDL3/SDL_error.h>
+#include <SDL3/SDL_properties.h>
+/* Thread synchronization primitives */
+#include <SDL3/SDL_atomic.h>
+#if defined(SDL_PLATFORM_WINDOWS)
+#include <process.h> /* _beginthreadex() and _endthreadex() */
+#endif
+#include <SDL3/SDL_begin_code.h>
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+/**
+* The SDL thread object.
+*
+* These are opaque data.
+*
+* \since This datatype is available since SDL 3.2.0.
+*
+* \sa SDL_CreateThread
+* \sa SDL_WaitThread
+*/
+typedef struct SDL_Thread SDL_Thread;
+/**
+* A unique numeric ID that identifies a thread.
+*
+* These are different from SDL_Thread objects, which are generally what an
+* application will operate on, but having a way to uniquely identify a thread
+* can be useful at times.
+*
+* \since This datatype is available since SDL 3.2.0.
+*
+* \sa SDL_GetThreadID
+* \sa SDL_GetCurrentThreadID
+*/
+typedef Uint64 SDL_ThreadID;
+/**
+* Thread local storage ID.
+*
+* 0 is the invalid ID. An app can create these and then set data for these
+* IDs that is unique to each thread.
+*
+* \since This datatype is available since SDL 3.2.0.
+*
+* \sa SDL_GetTLS
+* \sa SDL_SetTLS
+*/
+typedef SDL_AtomicInt SDL_TLSID;
+/**
+* The SDL thread priority.
+*
+* SDL will make system changes as necessary in order to apply the thread
+* priority. Code which attempts to control thread state related to priority
+* should be aware that calling SDL_SetCurrentThreadPriority may alter such
+* state. SDL_HINT_THREAD_PRIORITY_POLICY can be used to control aspects of
+* this behavior.
+*
+* \since This enum is available since SDL 3.2.0.
+*/
+typedef enum SDL_ThreadPriority {
+SDL_THREAD_PRIORITY_LOW,
+SDL_THREAD_PRIORITY_NORMAL,
+SDL_THREAD_PRIORITY_HIGH,
+SDL_THREAD_PRIORITY_TIME_CRITICAL
+} SDL_ThreadPriority;
+/**
+* The SDL thread state.
+*
+* The current state of a thread can be checked by calling SDL_GetThreadState.
+*
+* \since This enum is available since SDL 3.2.0.
+*
+* \sa SDL_GetThreadState
+*/
+typedef enum SDL_ThreadState
+{
+SDL_THREAD_UNKNOWN,     /**< The thread is not valid */
+SDL_THREAD_ALIVE,       /**< The thread is currently running */
+SDL_THREAD_DETACHED,    /**< The thread is detached and can't be waited on */
+SDL_THREAD_COMPLETE     /**< The thread has finished and should be cleaned up with SDL_WaitThread() */
+} SDL_ThreadState;
+/**
+* The function passed to SDL_CreateThread() as the new thread's entry point.
+*
+* \param data what was passed as `data` to SDL_CreateThread().
+* \returns a value that can be reported through SDL_WaitThread().
+*
+* \since This datatype is available since SDL 3.2.0.
+*/
+typedef int (SDLCALL *SDL_ThreadFunction) (void *data);
+#ifdef SDL_WIKI_DOCUMENTATION_SECTION
+/*
+* Note that these aren't the correct function signatures in this block, but
+* this is what the API reference manual should look like for all intents and
+* purposes.
+*
+* Technical details, not for the wiki (hello, header readers!)...
+*
+* On Windows (and maybe other platforms), a program might use a different
+* C runtime than its libraries. Or, in SDL's case, it might use a C runtime
+* while SDL uses none at all.
+*
+* C runtimes expect to initialize thread-specific details when a new thread
+* is created, but to do this in SDL_CreateThread would require SDL to know
+* intimate details about the caller's C runtime, which is not possible.
+*
+* So SDL_CreateThread has two extra parameters, which are
+* hidden at compile time by macros: the C runtime's `_beginthreadex` and
+* `_endthreadex` entry points. If these are not NULL, they are used to spin
+* and terminate the new thread; otherwise the standard Win32 `CreateThread`
+* function is used. When `SDL_CreateThread` is called from a compiler that
+* needs this C runtime thread init function, macros insert the appropriate
+* function pointers for SDL_CreateThread's caller (which might be a different
+* compiler with a different runtime in different calls to SDL_CreateThread!).
+*
+* SDL_BeginThreadFunction defaults to `_beginthreadex` on Windows (and NULL
+* everywhere else), but apps that have extremely specific special needs can
+* define this to something else and the SDL headers will use it, passing the
+* app-defined value to SDL_CreateThread calls. Redefine this with caution!
+*
+* Platforms that don't need _beginthread stuff (most everything) will fail
+* SDL_CreateThread with an error if these pointers _aren't_ NULL.
+*
+* Unless you are doing something extremely complicated, like perhaps a
+* language binding, **you should never deal with this directly**. Let SDL's
+* macros handle this platform-specific detail transparently!
+*/
+/**
+* Create a new thread with a default stack size.
+*
+* This is a convenience function, equivalent to calling
+* SDL_CreateThreadWithProperties with the following properties set:
+*
+* - `SDL_PROP_THREAD_CREATE_ENTRY_FUNCTION_POINTER`: `fn`
+* - `SDL_PROP_THREAD_CREATE_NAME_STRING`: `name`
+* - `SDL_PROP_THREAD_CREATE_USERDATA_POINTER`: `data`
+*
+* Note that this "function" is actually a macro that calls an internal
+* function with two extra parameters not listed here; they are hidden through
+* preprocessor macros and are needed to support various C runtimes at the
+* point of the function call. Language bindings that aren't using the C
+* headers will need to deal with this.
+*
+* Usually, apps should just call this function the same way on every platform
+* and let the macros hide the details.
+*
+* \param fn the SDL_ThreadFunction function to call in the new thread.
+* \param name the name of the thread.
+* \param data a pointer that is passed to `fn`.
+* \returns an opaque pointer to the new thread object on success, NULL if the
+*          new thread could not be created; call SDL_GetError() for more
+*          information.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_CreateThreadWithProperties
+* \sa SDL_WaitThread
+*/
+extern SDL_DECLSPEC SDL_Thread * SDLCALL SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data);
+/**
+* Create a new thread with with the specified properties.
+*
+* These are the supported properties:
+*
+* - `SDL_PROP_THREAD_CREATE_ENTRY_FUNCTION_POINTER`: an SDL_ThreadFunction
+*   value that will be called at the start of the new thread's life.
+*   Required.
+* - `SDL_PROP_THREAD_CREATE_NAME_STRING`: the name of the new thread, which
+*   might be available to debuggers. Optional, defaults to NULL.
+* - `SDL_PROP_THREAD_CREATE_USERDATA_POINTER`: an arbitrary app-defined
+*   pointer, which is passed to the entry function on the new thread, as its
+*   only parameter. Optional, defaults to NULL.
+* - `SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER`: the size, in bytes, of the new
+*   thread's stack. Optional, defaults to 0 (system-defined default).
+*
+* SDL makes an attempt to report `SDL_PROP_THREAD_CREATE_NAME_STRING` to the
+* system, so that debuggers can display it. Not all platforms support this.
+*
+* 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:
+*
+* https://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().
+*
+* The size (in bytes) of the new stack can be specified with
+* `SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER`. Zero means "use the system
+* default" which might be wildly different between platforms. x86 Linux
+* generally defaults to eight megabytes, an embedded device might be a few
+* kilobytes instead. You generally need to specify a stack that is a multiple
+* of the system's page size (in many cases, this is 4 kilobytes, but check
+* your system documentation).
+*
+* Note that this "function" is actually a macro that calls an internal
+* function with two extra parameters not listed here; they are hidden through
+* preprocessor macros and are needed to support various C runtimes at the
+* point of the function call. Language bindings that aren't using the C
+* headers will need to deal with this.
+*
+* The actual symbol in SDL is `SDL_CreateThreadWithPropertiesRuntime`, so
+* there is no symbol clash, but trying to load an SDL shared library and look
+* for "SDL_CreateThreadWithProperties" will fail.
+*
+* Usually, apps should just call this function the same way on every platform
+* and let the macros hide the details.
+*
+* \param props the properties to use.
+* \returns an opaque pointer to the new thread object on success, NULL if the
+*          new thread could not be created; call SDL_GetError() for more
+*          information.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_CreateThread
+* \sa SDL_WaitThread
+*/
+extern SDL_DECLSPEC SDL_Thread * SDLCALL SDL_CreateThreadWithProperties(SDL_PropertiesID props);
+#define SDL_PROP_THREAD_CREATE_ENTRY_FUNCTION_POINTER                  "SDL.thread.create.entry_function"
+#define SDL_PROP_THREAD_CREATE_NAME_STRING                             "SDL.thread.create.name"
+#define SDL_PROP_THREAD_CREATE_USERDATA_POINTER                        "SDL.thread.create.userdata"
+#define SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER                        "SDL.thread.create.stacksize"
+/* end wiki documentation for macros that are meant to look like functions. */
+#endif
+/* The real implementation, hidden from the wiki, so it can show this as real functions that don't have macro magic. */
+#ifndef SDL_WIKI_DOCUMENTATION_SECTION
+#  if defined(SDL_PLATFORM_WINDOWS)
+#    ifndef SDL_BeginThreadFunction
+#      define SDL_BeginThreadFunction _beginthreadex
+#    endif
+#    ifndef SDL_EndThreadFunction
+#      define SDL_EndThreadFunction _endthreadex
+#    endif
+#  endif
+#endif
+/* currently no other platforms than Windows use _beginthreadex/_endthreadex things. */
+#ifndef SDL_WIKI_DOCUMENTATION_SECTION
+#  ifndef SDL_BeginThreadFunction
+#    define SDL_BeginThreadFunction NULL
+#  endif
+#endif
+#ifndef SDL_WIKI_DOCUMENTATION_SECTION
+#  ifndef SDL_EndThreadFunction
+#    define SDL_EndThreadFunction NULL
+#  endif
+#endif
+#ifndef SDL_WIKI_DOCUMENTATION_SECTION
+/* These are the actual functions exported from SDL! Don't use them directly! Use the SDL_CreateThread and SDL_CreateThreadWithProperties macros! */
+/**
+* The actual entry point for SDL_CreateThread.
+*
+* \param fn the SDL_ThreadFunction function to call in the new thread
+* \param name the name of the thread
+* \param data a pointer that is passed to `fn`
+* \param pfnBeginThread the C runtime's _beginthreadex (or whatnot). Can be NULL.
+* \param pfnEndThread the C runtime's _endthreadex (or whatnot). Can be NULL.
+* \returns an opaque pointer to the new thread object on success, NULL if the
+*          new thread could not be created; call SDL_GetError() for more
+*          information.
+*
+* \since This function is available since SDL 3.2.0.
+*/
+extern SDL_DECLSPEC SDL_Thread * SDLCALL SDL_CreateThreadRuntime(SDL_ThreadFunction fn, const char *name, void *data, SDL_FunctionPointer pfnBeginThread, SDL_FunctionPointer pfnEndThread);
+/**
+* The actual entry point for SDL_CreateThreadWithProperties.
+*
+* \param props the properties to use
+* \param pfnBeginThread the C runtime's _beginthreadex (or whatnot). Can be NULL.
+* \param pfnEndThread the C runtime's _endthreadex (or whatnot). Can be NULL.
+* \returns an opaque pointer to the new thread object on success, NULL if the
+*          new thread could not be created; call SDL_GetError() for more
+*          information.
+*
+* \since This function is available since SDL 3.2.0.
+*/
+extern SDL_DECLSPEC SDL_Thread * SDLCALL SDL_CreateThreadWithPropertiesRuntime(SDL_PropertiesID props, SDL_FunctionPointer pfnBeginThread, SDL_FunctionPointer pfnEndThread);
+#define SDL_CreateThread(fn, name, data) SDL_CreateThreadRuntime((fn), (name), (data), (SDL_FunctionPointer) (SDL_BeginThreadFunction), (SDL_FunctionPointer) (SDL_EndThreadFunction))
+#define SDL_CreateThreadWithProperties(props) SDL_CreateThreadWithPropertiesRuntime((props), (SDL_FunctionPointer) (SDL_BeginThreadFunction), (SDL_FunctionPointer) (SDL_EndThreadFunction))
+#define SDL_PROP_THREAD_CREATE_ENTRY_FUNCTION_POINTER                  "SDL.thread.create.entry_function"
+#define SDL_PROP_THREAD_CREATE_NAME_STRING                             "SDL.thread.create.name"
+#define SDL_PROP_THREAD_CREATE_USERDATA_POINTER                        "SDL.thread.create.userdata"
+#define SDL_PROP_THREAD_CREATE_STACKSIZE_NUMBER                        "SDL.thread.create.stacksize"
+#endif
+/**
+* Get the thread name as it was specified in SDL_CreateThread().
+*
+* \param thread the thread to query.
+* \returns a pointer to a UTF-8 string that names the specified thread, or
+*          NULL if it doesn't have a name.
+*
+* \since This function is available since SDL 3.2.0.
+*/
+extern SDL_DECLSPEC const char * SDLCALL SDL_GetThreadName(SDL_Thread *thread);
+/**
+* Get the thread identifier for the current thread.
+*
+* This thread identifier is as reported by the underlying operating system.
+* If SDL is running on a platform that does not support threads the return
+* value will always be zero.
+*
+* This function also returns a valid thread ID when called from the main
+* thread.
+*
+* \returns the ID of the current thread.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_GetThreadID
+*/
+extern SDL_DECLSPEC SDL_ThreadID SDLCALL SDL_GetCurrentThreadID(void);
+/**
+* Get the thread identifier for the specified thread.
+*
+* This thread identifier is as reported by the underlying operating system.
+* If SDL is running on a platform that does not support threads the return
+* value will always be zero.
+*
+* \param thread the thread to query.
+* \returns the ID of the specified thread, or the ID of the current thread if
+*          `thread` is NULL.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_GetCurrentThreadID
+*/
+extern SDL_DECLSPEC SDL_ThreadID SDLCALL SDL_GetThreadID(SDL_Thread *thread);
+/**
+* Set the priority for the current thread.
+*
+* Note that some platforms will not let you alter the priority (or at least,
+* promote the thread to a higher priority) at all, and some require you to be
+* an administrator account. Be prepared for this to fail.
+*
+* \param priority the SDL_ThreadPriority to set.
+* \returns true on success or false on failure; call SDL_GetError() for more
+*          information.
+*
+* \since This function is available since SDL 3.2.0.
+*/
+extern SDL_DECLSPEC bool SDLCALL SDL_SetCurrentThreadPriority(SDL_ThreadPriority priority);
+/**
+* Wait for a thread to finish.
+*
+* Threads that haven't been detached will remain 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 from the thread function is placed in the area pointed to
+* by `status`, if `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 a NULL thread to this function; it is a no-op.
+*
+* Note that the thread pointer is freed by this function and is not valid
+* afterward.
+*
+* \param thread the SDL_Thread pointer that was returned from the
+*               SDL_CreateThread() call that started this thread.
+* \param status a pointer filled in with the value returned from the thread
+*               function by its 'return', or -1 if the thread has been
+*               detached or isn't valid, may be NULL.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_CreateThread
+* \sa SDL_DetachThread
+*/
+extern SDL_DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread *thread, int *status);
+/**
+* Get the current state of a thread.
+*
+* \param thread the thread to query.
+* \returns the current state of a thread, or SDL_THREAD_UNKNOWN if the thread
+*          isn't valid.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_ThreadState
+*/
+extern SDL_DECLSPEC SDL_ThreadState SDLCALL SDL_GetThreadState(SDL_Thread *thread);
+/**
+* Let a thread clean up on exit without intervention.
+*
+* 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.
+*
+* \param thread the SDL_Thread pointer that was returned from the
+*               SDL_CreateThread() call that started this thread.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_CreateThread
+* \sa SDL_WaitThread
+*/
+extern SDL_DECLSPEC void SDLCALL SDL_DetachThread(SDL_Thread *thread);
+/**
+* Get the current thread's value associated with a thread local storage ID.
+*
+* \param id a pointer to the thread local storage ID, may not be NULL.
+* \returns the value associated with the ID for the current thread or NULL if
+*          no value has been set; call SDL_GetError() for more information.
+*
+* \threadsafety It is safe to call this function from any thread.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_SetTLS
+*/
+extern SDL_DECLSPEC void * SDLCALL SDL_GetTLS(SDL_TLSID *id);
+/**
+* The callback used to cleanup data passed to SDL_SetTLS.
+*
+* This is called when a thread exits, to allow an app to free any resources.
+*
+* \param value a pointer previously handed to SDL_SetTLS.
+*
+* \since This datatype is available since SDL 3.2.0.
+*
+* \sa SDL_SetTLS
+*/
+typedef void (SDLCALL *SDL_TLSDestructorCallback)(void *value);
+/**
+* Set the current thread's value associated with a thread local storage ID.
+*
+* If the thread local storage ID is not initialized (the value is 0), a new
+* ID will be created in a thread-safe way, so all calls using a pointer to
+* the same ID will refer to the same local storage.
+*
+* Note that replacing a value from a previous call to this function on the
+* same thread does _not_ call the previous value's destructor!
+*
+* `destructor` can be NULL; it is assumed that `value` does not need to be
+* cleaned up if so.
+*
+* \param id a pointer to the thread local storage ID, may not be NULL.
+* \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, may be NULL.
+* \returns true on success or false on failure; call SDL_GetError() for more
+*          information.
+*
+* \threadsafety It is safe to call this function from any thread.
+*
+* \since This function is available since SDL 3.2.0.
+*
+* \sa SDL_GetTLS
+*/
+extern SDL_DECLSPEC bool SDLCALL SDL_SetTLS(SDL_TLSID *id, const void *value, SDL_TLSDestructorCallback destructor);
+/**
+* Cleanup all TLS data for this thread.
+*
+* If you are creating your threads outside of SDL and then calling SDL
+* functions, you should call this function before your thread exits, to
+* properly clean up SDL memory.
+*
+* \threadsafety It is safe to call this function from any thread.
+*
+* \since This function is available since SDL 3.2.0.
+*/
+extern SDL_DECLSPEC void SDLCALL SDL_CleanupTLS(void);
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+}
+#endif
+#include <SDL3/SDL_close_code.h>
+#endif /* SDL_thread_h_ */

Mercurial > foo_out_sdl

comparison SDL3/SDL_thread.h @ 1:20d02a178406 default tip