include/SDL_thread.h
author Ryan C. Gordon <icculus@icculus.org>
Sat, 20 Jul 2013 19:51:51 -0400
changeset 7482 249d8ecbbb7d
parent 7418 5689b9b47f8c
child 7528 1890a896802f
permissions -rw-r--r--
Fixed some compiler warnings that Visual Studio reported.
slouken@0
     1
/*
slouken@5535
     2
  Simple DirectMedia Layer
slouken@6885
     3
  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
slouken@0
     4
slouken@5535
     5
  This software is provided 'as-is', without any express or implied
slouken@5535
     6
  warranty.  In no event will the authors be held liable for any damages
slouken@5535
     7
  arising from the use of this software.
slouken@0
     8
slouken@5535
     9
  Permission is granted to anyone to use this software for any purpose,
slouken@5535
    10
  including commercial applications, and to alter it and redistribute it
slouken@5535
    11
  freely, subject to the following restrictions:
slouken@0
    12
slouken@5535
    13
  1. The origin of this software must not be misrepresented; you must not
slouken@5535
    14
     claim that you wrote the original software. If you use this software
slouken@5535
    15
     in a product, an acknowledgment in the product documentation would be
slouken@5535
    16
     appreciated but is not required.
slouken@5535
    17
  2. Altered source versions must be plainly marked as such, and must not be
slouken@5535
    18
     misrepresented as being the original software.
slouken@5535
    19
  3. This notice may not be removed or altered from any source distribution.
slouken@0
    20
*/
slouken@0
    21
slouken@0
    22
#ifndef _SDL_thread_h
slouken@0
    23
#define _SDL_thread_h
slouken@0
    24
slouken@1895
    25
/**
slouken@3407
    26
 *  \file SDL_thread.h
slouken@7191
    27
 *
slouken@3407
    28
 *  Header for the SDL thread management routines.
slouken@1895
    29
 */
slouken@0
    30
slouken@1356
    31
#include "SDL_stdinc.h"
slouken@1358
    32
#include "SDL_error.h"
slouken@0
    33
slouken@0
    34
/* Thread synchronization primitives */
slouken@7391
    35
#include "SDL_atomic.h"
slouken@0
    36
#include "SDL_mutex.h"
slouken@0
    37
slouken@0
    38
#include "begin_code.h"
slouken@0
    39
/* Set up for C function definitions, even when using C++ */
slouken@0
    40
#ifdef __cplusplus
slouken@0
    41
extern "C" {
slouken@0
    42
#endif
slouken@0
    43
slouken@0
    44
/* The SDL thread structure, defined in SDL_thread.c */
slouken@0
    45
struct SDL_Thread;
slouken@0
    46
typedef struct SDL_Thread SDL_Thread;
slouken@0
    47
slouken@3578
    48
/* The SDL thread ID */
slouken@3578
    49
typedef unsigned long SDL_threadID;
slouken@3578
    50
slouken@7393
    51
/* Thread local storage ID, 0 is the invalid ID */
icculus@7482
    52
typedef unsigned int SDL_TLSID;
slouken@7391
    53
slouken@5506
    54
/* The SDL thread priority
slouken@5506
    55
 *
slouken@5506
    56
 * Note: On many systems you require special privileges to set high priority.
slouken@5506
    57
 */
slouken@5506
    58
typedef enum {
slouken@5506
    59
    SDL_THREAD_PRIORITY_LOW,
slouken@5506
    60
    SDL_THREAD_PRIORITY_NORMAL,
slouken@5506
    61
    SDL_THREAD_PRIORITY_HIGH
slouken@5506
    62
} SDL_ThreadPriority;
slouken@5506
    63
slouken@4866
    64
/* The function passed to SDL_CreateThread()
slouken@4866
    65
   It is passed a void* user context parameter and returns an int.
slouken@4866
    66
 */
slouken@4866
    67
typedef int (SDLCALL * SDL_ThreadFunction) (void *data);
slouken@4866
    68
slouken@5086
    69
#if defined(__WIN32__) && !defined(HAVE_LIBC)
slouken@3407
    70
/**
slouken@3407
    71
 *  \file SDL_thread.h
slouken@7191
    72
 *
slouken@3407
    73
 *  We compile SDL into a DLL. This means, that it's the DLL which
slouken@3407
    74
 *  creates a new thread for the calling process with the SDL_CreateThread()
slouken@3407
    75
 *  API. There is a problem with this, that only the RTL of the SDL.DLL will
slouken@7191
    76
 *  be initialized for those threads, and not the RTL of the calling
slouken@3407
    77
 *  application!
slouken@7191
    78
 *
slouken@3407
    79
 *  To solve this, we make a little hack here.
slouken@7191
    80
 *
slouken@3407
    81
 *  We'll always use the caller's _beginthread() and _endthread() APIs to
slouken@3407
    82
 *  start a new thread. This way, if it's the SDL.DLL which uses this API,
slouken@3407
    83
 *  then the RTL of SDL.DLL will be used to create the new thread, and if it's
slouken@3407
    84
 *  the application, then the RTL of the application will be used.
slouken@7191
    85
 *
slouken@3407
    86
 *  So, in short:
slouken@7191
    87
 *  Always use the _beginthread() and _endthread() of the calling runtime
slouken@3407
    88
 *  library!
slouken@3407
    89
 */
slouken@1471
    90
#define SDL_PASSED_BEGINTHREAD_ENDTHREAD
slouken@1895
    91
#include <process.h>            /* This has _beginthread() and _endthread() defined! */
icculus@1190
    92
slouken@1895
    93
typedef uintptr_t(__cdecl * pfnSDL_CurrentBeginThread) (void *, unsigned,
slouken@1895
    94
                                                        unsigned (__stdcall *
slouken@1895
    95
                                                                  func) (void
slouken@1895
    96
                                                                         *),
slouken@1895
    97
                                                        void *arg, unsigned,
slouken@1895
    98
                                                        unsigned *threadID);
slouken@1895
    99
typedef void (__cdecl * pfnSDL_CurrentEndThread) (unsigned code);
icculus@1190
   100
slouken@3407
   101
/**
slouken@3407
   102
 *  Create a thread.
slouken@3407
   103
 */
slouken@2060
   104
extern DECLSPEC SDL_Thread *SDLCALL
icculus@5969
   105
SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data,
slouken@2060
   106
                 pfnSDL_CurrentBeginThread pfnBeginThread,
slouken@2060
   107
                 pfnSDL_CurrentEndThread pfnEndThread);
icculus@1190
   108
slouken@3407
   109
/**
slouken@3407
   110
 *  Create a thread.
slouken@3407
   111
 */
icculus@5969
   112
#define SDL_CreateThread(fn, name, data) SDL_CreateThread(fn, name, data, _beginthreadex, _endthreadex)
slouken@3407
   113
icculus@1190
   114
#else
slouken@3407
   115
slouken@3407
   116
/**
slouken@3407
   117
 *  Create a thread.
icculus@5969
   118
 *
icculus@5969
   119
 *   Thread naming is a little complicated: Most systems have very small
icculus@5969
   120
 *    limits for the string length (BeOS has 32 bytes, Linux currently has 16,
icculus@5969
   121
 *    Visual C++ 6.0 has nine!), and possibly other arbitrary rules. You'll
icculus@5969
   122
 *    have to see what happens with your system's debugger. The name should be
icculus@5969
   123
 *    UTF-8 (but using the naming limits of C identifiers is a better bet).
icculus@5969
   124
 *   There are no requirements for thread naming conventions, so long as the
icculus@5969
   125
 *    string is null-terminated UTF-8, but these guidelines are helpful in
icculus@5969
   126
 *    choosing a name:
icculus@5969
   127
 *
icculus@5969
   128
 *    http://stackoverflow.com/questions/149932/naming-conventions-for-threads
icculus@5969
   129
 *
icculus@5969
   130
 *   If a system imposes requirements, SDL will try to munge the string for
icculus@5969
   131
 *    it (truncate, etc), but the original string contents will be available
icculus@5969
   132
 *    from SDL_GetThreadName().
slouken@3407
   133
 */
slouken@1895
   134
extern DECLSPEC SDL_Thread *SDLCALL
icculus@5969
   135
SDL_CreateThread(SDL_ThreadFunction fn, const char *name, void *data);
slouken@3407
   136
icculus@1190
   137
#endif
slouken@0
   138
slouken@3407
   139
/**
icculus@5969
   140
 * Get the thread name, as it was specified in SDL_CreateThread().
icculus@5969
   141
 *  This function returns a pointer to a UTF-8 string that names the
icculus@5969
   142
 *  specified thread, or NULL if it doesn't have a name. This is internal
icculus@5969
   143
 *  memory, not to be free()'d by the caller, and remains valid until the
icculus@5969
   144
 *  specified thread is cleaned up by SDL_WaitThread().
icculus@5969
   145
 */
icculus@5969
   146
extern DECLSPEC const char *SDLCALL SDL_GetThreadName(SDL_Thread *thread);
icculus@5969
   147
icculus@5969
   148
/**
slouken@3578
   149
 *  Get the thread identifier for the current thread.
slouken@3407
   150
 */
slouken@3578
   151
extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
slouken@0
   152
slouken@3407
   153
/**
slouken@3578
   154
 *  Get the thread identifier for the specified thread.
slouken@7191
   155
 *
slouken@3407
   156
 *  Equivalent to SDL_ThreadID() if the specified thread is NULL.
slouken@0
   157
 */
slouken@3578
   158
extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
slouken@0
   159
slouken@3407
   160
/**
slouken@5509
   161
 *  Set the priority for the current thread
slouken@5506
   162
 */
slouken@5509
   163
extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_ThreadPriority priority);
slouken@5506
   164
slouken@5506
   165
/**
slouken@3407
   166
 *  Wait for a thread to finish.
slouken@7191
   167
 *
slouken@3407
   168
 *  The return code for the thread function is placed in the area
slouken@3407
   169
 *  pointed to by \c status, if \c status is not NULL.
slouken@0
   170
 */
slouken@1895
   171
extern DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread * thread, int *status);
slouken@0
   172
slouken@7391
   173
/**
slouken@7391
   174
 *  \brief Create an identifier that is globally visible to all threads but refers to data that is thread-specific.
slouken@7391
   175
 *
slouken@7391
   176
 *  \return The newly created thread local storage identifier, or 0 on error
slouken@7391
   177
 *
slouken@7391
   178
 *  \code
slouken@7391
   179
 *  static SDL_SpinLock tls_lock;
slouken@7391
   180
 *  static SDL_TLSID thread_local_storage;
slouken@7391
   181
 * 
slouken@7391
   182
 *  void SetMyThreadData(void *value)
slouken@7391
   183
 *  {
slouken@7391
   184
 *      if (!thread_local_storage) {
slouken@7391
   185
 *          SDL_AtomicLock(&tls_lock);
slouken@7391
   186
 *          if (!thread_local_storage) {
slouken@7391
   187
 *              thread_local_storage = SDL_TLSCreate();
slouken@7391
   188
 *          }
slouken@7391
   189
 *          SDL_AtomicUnLock(&tls_lock);
slouken@7391
   190
 *      }
slouken@7391
   191
 *      SDL_TLSSet(thread_local_storage, value);
slouken@7391
   192
 *  }
slouken@7391
   193
 *  
slouken@7391
   194
 *  void *GetMyThreadData(void)
slouken@7391
   195
 *  {
slouken@7391
   196
 *      return SDL_TLSGet(thread_local_storage);
slouken@7391
   197
 *  }
slouken@7391
   198
 *  \endcode
slouken@7391
   199
 *
slouken@7391
   200
 *  \sa SDL_TLSGet()
slouken@7391
   201
 *  \sa SDL_TLSSet()
slouken@7391
   202
 */
dimitris@7418
   203
extern DECLSPEC SDL_TLSID SDLCALL SDL_TLSCreate(void);
slouken@7391
   204
slouken@7391
   205
/**
slouken@7391
   206
 *  \brief Get the value associated with a thread local storage ID for the current thread.
slouken@7391
   207
 *
slouken@7391
   208
 *  \param id The thread local storage ID
slouken@7391
   209
 *
slouken@7391
   210
 *  \return The value associated with the ID for the current thread, or NULL if no value has been set.
slouken@7391
   211
 *
slouken@7391
   212
 *  \sa SDL_TLSCreate()
slouken@7391
   213
 *  \sa SDL_TLSSet()
slouken@7391
   214
 */
slouken@7391
   215
extern DECLSPEC void * SDLCALL SDL_TLSGet(SDL_TLSID id);
slouken@7391
   216
slouken@7391
   217
/**
slouken@7391
   218
 *  \brief Set the value associated with a thread local storage ID for the current thread.
slouken@7391
   219
 *
slouken@7391
   220
 *  \param id The thread local storage ID
slouken@7391
   221
 *  \param value The value to associate with the ID for the current thread
slouken@7393
   222
 *  \param destructor A function called when the thread exits, to free the value.
slouken@7391
   223
 *
slouken@7391
   224
 *  \return 0 on success, -1 on error
slouken@7391
   225
 *
slouken@7391
   226
 *  \sa SDL_TLSCreate()
slouken@7391
   227
 *  \sa SDL_TLSGet()
slouken@7391
   228
 */
slouken@7393
   229
extern DECLSPEC int SDLCALL SDL_TLSSet(SDL_TLSID id, const void *value, void (*destructor)(void*));
slouken@7391
   230
slouken@0
   231
slouken@0
   232
/* Ends C function definitions when using C++ */
slouken@0
   233
#ifdef __cplusplus
slouken@0
   234
}
slouken@0
   235
#endif
slouken@0
   236
#include "close_code.h"
slouken@0
   237
slouken@0
   238
#endif /* _SDL_thread_h */
slouken@1895
   239
slouken@1895
   240
/* vi: set ts=4 sw=4 expandtab: */