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/*
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SDL - Simple DirectMedia Layer
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Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Sam Lantinga
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slouken@devolution.com
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*/
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#ifdef SAVE_RCSID
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static char rcsid =
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"@(#) $Id$";
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#endif
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/* System independent thread management routines for SDL */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "SDL_error.h"
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#include "SDL_mutex.h"
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#include "SDL_thread.h"
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#include "SDL_thread_c.h"
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#include "SDL_systhread.h"
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#define ARRAY_CHUNKSIZE 32
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/* The array of threads currently active in the application
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(except the main thread)
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The manipulation of an array here is safer than using a linked list.
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*/
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static int SDL_maxthreads = 0;
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static int SDL_numthreads = 0;
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static SDL_Thread **SDL_Threads = NULL;
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static SDL_mutex *thread_lock = NULL;
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int _creating_thread_lock = 0;
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int SDL_ThreadsInit(void)
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{
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int retval;
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retval = 0;
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/* Set the thread lock creation flag so that we can reuse an
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existing lock on the system - since this mutex never gets
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destroyed (see SDL_ThreadsQuit()), we want to reuse it.
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*/
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_creating_thread_lock = 1;
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thread_lock = SDL_CreateMutex();
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_creating_thread_lock = 0;
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if ( thread_lock == NULL ) {
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retval = -1;
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}
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return(retval);
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}
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/* This should never be called...
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If this is called by SDL_Quit(), we don't know whether or not we should
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clean up threads here. If any threads are still running after this call,
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they will no longer have access to any per-thread data.
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*/
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void SDL_ThreadsQuit()
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{
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SDL_mutex *mutex;
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mutex = thread_lock;
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thread_lock = NULL;
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if ( mutex != NULL ) {
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SDL_DestroyMutex(mutex);
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}
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}
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/* Routines for manipulating the thread list */
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static void SDL_AddThread(SDL_Thread *thread)
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{
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SDL_Thread **threads;
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/* WARNING:
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If the very first threads are created simultaneously, then
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there could be a race condition causing memory corruption.
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In practice, this isn't a problem because by definition there
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is only one thread running the first time this is called.
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*/
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if ( thread_lock == NULL ) {
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if ( SDL_ThreadsInit() < 0 ) {
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return;
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}
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}
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SDL_mutexP(thread_lock);
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/* Expand the list of threads, if necessary */
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#ifdef DEBUG_THREADS
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printf("Adding thread (%d already - %d max)\n",
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SDL_numthreads, SDL_maxthreads);
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#endif
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if ( SDL_numthreads == SDL_maxthreads ) {
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threads=(SDL_Thread **)malloc((SDL_maxthreads+ARRAY_CHUNKSIZE)*
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(sizeof *threads));
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if ( threads == NULL ) {
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SDL_OutOfMemory();
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goto done;
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}
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memcpy(threads, SDL_Threads, SDL_numthreads*(sizeof *threads));
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SDL_maxthreads += ARRAY_CHUNKSIZE;
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if ( SDL_Threads ) {
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free(SDL_Threads);
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}
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SDL_Threads = threads;
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}
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SDL_Threads[SDL_numthreads++] = thread;
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done:
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SDL_mutexV(thread_lock);
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}
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static void SDL_DelThread(SDL_Thread *thread)
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{
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int i;
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if ( thread_lock ) {
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SDL_mutexP(thread_lock);
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for ( i=0; i<SDL_numthreads; ++i ) {
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if ( thread == SDL_Threads[i] ) {
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break;
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}
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}
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if ( i < SDL_numthreads ) {
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--SDL_numthreads;
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while ( i < SDL_numthreads ) {
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SDL_Threads[i] = SDL_Threads[i+1];
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++i;
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}
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#ifdef DEBUG_THREADS
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printf("Deleting thread (%d left - %d max)\n",
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SDL_numthreads, SDL_maxthreads);
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#endif
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}
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SDL_mutexV(thread_lock);
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}
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}
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/* The default (non-thread-safe) global error variable */
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static SDL_error SDL_global_error;
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/* Routine to get the thread-specific error variable */
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SDL_error *SDL_GetErrBuf(void)
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{
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SDL_error *errbuf;
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errbuf = &SDL_global_error;
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if ( SDL_Threads ) {
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int i;
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Uint32 this_thread;
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this_thread = SDL_ThreadID();
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SDL_mutexP(thread_lock);
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for ( i=0; i<SDL_numthreads; ++i ) {
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if ( this_thread == SDL_Threads[i]->threadid ) {
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errbuf = &SDL_Threads[i]->errbuf;
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break;
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}
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}
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SDL_mutexV(thread_lock);
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}
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return(errbuf);
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}
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/* Arguments and callback to setup and run the user thread function */
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typedef struct {
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int (*func)(void *);
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void *data;
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SDL_Thread *info;
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SDL_sem *wait;
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} thread_args;
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void SDL_RunThread(void *data)
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{
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thread_args *args;
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int (*userfunc)(void *);
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void *userdata;
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int *statusloc;
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/* Perform any system-dependent setup
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- this function cannot fail, and cannot use SDL_SetError()
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*/
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SDL_SYS_SetupThread();
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/* Get the thread id */
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args = (thread_args *)data;
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args->info->threadid = SDL_ThreadID();
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/* Figure out what function to run */
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userfunc = args->func;
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userdata = args->data;
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statusloc = &args->info->status;
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/* Wake up the parent thread */
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SDL_SemPost(args->wait);
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/* Run the function */
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*statusloc = userfunc(userdata);
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}
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SDL_Thread *SDL_CreateThread(int (*fn)(void *), void *data)
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{
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SDL_Thread *thread;
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thread_args *args;
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int ret;
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/* Allocate memory for the thread info structure */
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thread = (SDL_Thread *)malloc(sizeof(*thread));
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if ( thread == NULL ) {
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SDL_OutOfMemory();
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return(NULL);
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}
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memset(thread, 0, (sizeof *thread));
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thread->status = -1;
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/* Set up the arguments for the thread */
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args = (thread_args *)malloc(sizeof(*args));
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if ( args == NULL ) {
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SDL_OutOfMemory();
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free(thread);
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return(NULL);
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}
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args->func = fn;
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args->data = data;
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args->info = thread;
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args->wait = SDL_CreateSemaphore(0);
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if ( args->wait == NULL ) {
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free(thread);
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free(args);
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return(NULL);
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}
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/* Add the thread to the list of available threads */
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SDL_AddThread(thread);
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/* Create the thread and go! */
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ret = SDL_SYS_CreateThread(thread, args);
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if ( ret >= 0 ) {
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/* Wait for the thread function to use arguments */
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SDL_SemWait(args->wait);
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} else {
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/* Oops, failed. Gotta free everything */
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SDL_DelThread(thread);
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free(thread);
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thread = NULL;
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}
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SDL_DestroySemaphore(args->wait);
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free(args);
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/* Everything is running now */
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return(thread);
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}
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void SDL_WaitThread(SDL_Thread *thread, int *status)
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{
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if ( thread ) {
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SDL_SYS_WaitThread(thread);
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if ( status ) {
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*status = thread->status;
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}
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SDL_DelThread(thread);
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free(thread);
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}
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}
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Uint32 SDL_GetThreadID(SDL_Thread *thread)
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{
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Uint32 id;
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if ( thread ) {
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id = thread->threadid;
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} else {
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id = SDL_ThreadID();
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}
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return(id);
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}
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void SDL_KillThread(SDL_Thread *thread)
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{
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if ( thread ) {
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SDL_SYS_KillThread(thread);
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SDL_WaitThread(thread, NULL);
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}
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}
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