include/SDL_thread.h
author Sam Lantinga <slouken@libsdl.org>
Fri, 25 Mar 2011 10:47:49 -0700
changeset 5506 82a09d5d0f07
parent 5262 b530ef003506
child 5509 5b1b4d820d10
permissions -rw-r--r--
Implemented SDL_SetThreadPriority()
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2011 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 #ifndef _SDL_thread_h
    24 #define _SDL_thread_h
    25 
    26 /**
    27  *  \file SDL_thread.h
    28  *  
    29  *  Header for the SDL thread management routines.
    30  */
    31 
    32 #include "SDL_stdinc.h"
    33 #include "SDL_error.h"
    34 
    35 /* Thread synchronization primitives */
    36 #include "SDL_mutex.h"
    37 
    38 #include "begin_code.h"
    39 /* Set up for C function definitions, even when using C++ */
    40 #ifdef __cplusplus
    41 /* *INDENT-OFF* */
    42 extern "C" {
    43 /* *INDENT-ON* */
    44 #endif
    45 
    46 /* The SDL thread structure, defined in SDL_thread.c */
    47 struct SDL_Thread;
    48 typedef struct SDL_Thread SDL_Thread;
    49 
    50 /* The SDL thread ID */
    51 typedef unsigned long SDL_threadID;
    52 
    53 /* The SDL thread priority
    54  *
    55  * Note: On many systems you require special privileges to set high priority.
    56  */
    57 typedef enum {
    58     SDL_THREAD_PRIORITY_LOW,
    59     SDL_THREAD_PRIORITY_NORMAL,
    60     SDL_THREAD_PRIORITY_HIGH
    61 } SDL_ThreadPriority;
    62 
    63 /* The function passed to SDL_CreateThread()
    64    It is passed a void* user context parameter and returns an int.
    65  */
    66 typedef int (SDLCALL * SDL_ThreadFunction) (void *data);
    67 
    68 #if defined(__WIN32__) && !defined(HAVE_LIBC)
    69 /**
    70  *  \file SDL_thread.h
    71  *  
    72  *  We compile SDL into a DLL. This means, that it's the DLL which
    73  *  creates a new thread for the calling process with the SDL_CreateThread()
    74  *  API. There is a problem with this, that only the RTL of the SDL.DLL will
    75  *  be initialized for those threads, and not the RTL of the calling 
    76  *  application!
    77  *  
    78  *  To solve this, we make a little hack here.
    79  *  
    80  *  We'll always use the caller's _beginthread() and _endthread() APIs to
    81  *  start a new thread. This way, if it's the SDL.DLL which uses this API,
    82  *  then the RTL of SDL.DLL will be used to create the new thread, and if it's
    83  *  the application, then the RTL of the application will be used.
    84  *  
    85  *  So, in short:
    86  *  Always use the _beginthread() and _endthread() of the calling runtime 
    87  *  library!
    88  */
    89 #define SDL_PASSED_BEGINTHREAD_ENDTHREAD
    90 #ifndef _WIN32_WCE
    91 #include <process.h>            /* This has _beginthread() and _endthread() defined! */
    92 #endif
    93 
    94 #ifdef __GNUC__
    95 typedef unsigned long (__cdecl * pfnSDL_CurrentBeginThread) (void *, unsigned,
    96                                                              unsigned
    97                                                              (__stdcall *
    98                                                               func) (void *),
    99                                                              void *arg,
   100                                                              unsigned,
   101                                                              unsigned
   102                                                              *threadID);
   103 typedef void (__cdecl * pfnSDL_CurrentEndThread) (unsigned code);
   104 #else
   105 typedef uintptr_t(__cdecl * pfnSDL_CurrentBeginThread) (void *, unsigned,
   106                                                         unsigned (__stdcall *
   107                                                                   func) (void
   108                                                                          *),
   109                                                         void *arg, unsigned,
   110                                                         unsigned *threadID);
   111 typedef void (__cdecl * pfnSDL_CurrentEndThread) (unsigned code);
   112 #endif
   113 
   114 /**
   115  *  Create a thread.
   116  */
   117 extern DECLSPEC SDL_Thread *SDLCALL
   118 SDL_CreateThread(SDL_ThreadFunction fn, void *data,
   119                  pfnSDL_CurrentBeginThread pfnBeginThread,
   120                  pfnSDL_CurrentEndThread pfnEndThread);
   121 
   122 #if defined(_WIN32_WCE)
   123 
   124 /**
   125  *  Create a thread.
   126  */
   127 #define SDL_CreateThread(fn, data) SDL_CreateThread(fn, data, NULL, NULL)
   128 
   129 #else
   130 
   131 /**
   132  *  Create a thread.
   133  */
   134 #define SDL_CreateThread(fn, data) SDL_CreateThread(fn, data, _beginthreadex, _endthreadex)
   135 
   136 #endif
   137 #else
   138 
   139 /**
   140  *  Create a thread.
   141  */
   142 extern DECLSPEC SDL_Thread *SDLCALL
   143 SDL_CreateThread(SDL_ThreadFunction fn, void *data);
   144 
   145 #endif
   146 
   147 /**
   148  *  Get the thread identifier for the current thread.
   149  */
   150 extern DECLSPEC SDL_threadID SDLCALL SDL_ThreadID(void);
   151 
   152 /**
   153  *  Get the thread identifier for the specified thread.
   154  *  
   155  *  Equivalent to SDL_ThreadID() if the specified thread is NULL.
   156  */
   157 extern DECLSPEC SDL_threadID SDLCALL SDL_GetThreadID(SDL_Thread * thread);
   158 
   159 /**
   160  *  Set the thread priority
   161  */
   162 extern DECLSPEC int SDLCALL SDL_SetThreadPriority(SDL_Thread * thread, SDL_ThreadPriority priority);
   163 
   164 /**
   165  *  Wait for a thread to finish.
   166  *  
   167  *  The return code for the thread function is placed in the area
   168  *  pointed to by \c status, if \c status is not NULL.
   169  */
   170 extern DECLSPEC void SDLCALL SDL_WaitThread(SDL_Thread * thread, int *status);
   171 
   172 
   173 /* Ends C function definitions when using C++ */
   174 #ifdef __cplusplus
   175 /* *INDENT-OFF* */
   176 }
   177 /* *INDENT-ON* */
   178 #endif
   179 #include "close_code.h"
   180 
   181 #endif /* _SDL_thread_h */
   182 
   183 /* vi: set ts=4 sw=4 expandtab: */