git.sesse.net Git - vlc/blob - include/threads.h

   1 /*****************************************************************************
   2  * threads.h : threads implementation for the VideoLAN client
   3  * This header provides a portable threads implementation.
   4  *****************************************************************************
   5  * Copyright (C) 1999, 2000 VideoLAN
   6  * $Id: threads.h,v 1.19 2001/06/14 20:21:04 sam Exp $
   7  *
   8  * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
   9  *          Samuel Hocevar <sam@via.ecp.fr>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  24  *****************************************************************************/
  25
  26 #include <stdio.h>
  27
  28 #ifdef PROFILING
  29 #   include <sys/time.h>
  30 #endif
  31
  32 #if defined( PTH_INIT_IN_PTH_H )                                  /* GNU Pth */
  33 #   include <pth.h>
  34
  35 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )  /* pthreads (like Linux & BSD) */
  36 #   include <pthread.h>
  37
  38 #elif defined( HAVE_CTHREADS_H )                                  /* GNUMach */
  39 #   include <cthreads.h>
  40
  41 #elif defined( HAVE_KERNEL_SCHEDULER_H )                             /* BeOS */
  42 #   undef MAX
  43 #   undef MIN
  44 #   include <kernel/OS.h>
  45 #   include <kernel/scheduler.h>
  46 #   include <byteorder.h>
  47
  48 #elif defined( WIN32 )                        /* Win32 with MinGW32 compiler */
  49 #   include <windows.h>
  50 #   include <process.h>
  51
  52 #else
  53 #   error no threads available on your system !
  54
  55 #endif
  56
  57 /*****************************************************************************
  58  * Constants
  59  *****************************************************************************
  60  * These constants are used by all threads in *_CreateThread() and
  61  * *_DestroyThreads() functions. Since those calls are non-blocking, an integer
  62  * value is used as a shared flag to represent the status of the thread.
  63  *****************************************************************************/
  64
  65 /* Void status - this value can be used to make sure no operation is currently
  66  * in progress on the concerned thread in an array of recorded threads */
  67 #define THREAD_NOP          0                            /* nothing happened */
  68
  69 /* Creation status */
  70 #define THREAD_CREATE       10                     /* thread is initializing */
  71 #define THREAD_START        11                          /* thread has forked */
  72 #define THREAD_READY        19                            /* thread is ready */
  73
  74 /* Destructions status */
  75 #define THREAD_DESTROY      20            /* destruction order has been sent */
  76 #define THREAD_END          21        /* destruction order has been received */
  77 #define THREAD_OVER         29             /* thread does not exist any more */
  78
  79 /* Error status */
  80 #define THREAD_ERROR        30                           /* an error occured */
  81 #define THREAD_FATAL        31  /* an fatal error occured - program must end */
  82
  83 /*****************************************************************************
  84  * Types definition
  85  *****************************************************************************/
  86
  87 #if defined( PTH_INIT_IN_PTH_H )
  88 typedef pth_t            vlc_thread_t;
  89 typedef pth_mutex_t      vlc_mutex_t;
  90 typedef pth_cond_t       vlc_cond_t;
  91
  92 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
  93 typedef pthread_t        vlc_thread_t;
  94 typedef pthread_mutex_t  vlc_mutex_t;
  95 typedef pthread_cond_t   vlc_cond_t;
  96
  97 #elif defined( HAVE_CTHREADS_H )
  98 typedef cthread_t        vlc_thread_t;
  99
 100 /* Those structs are the ones defined in /include/cthreads.h but we need
 101  * to handle (*foo) where foo is a (mutex_t) while they handle (foo) where
 102  * foo is a (mutex_t*) */
 103 typedef struct s_mutex {
 104     spin_lock_t held;
 105     spin_lock_t lock;
 106     char *name;
 107     struct cthread_queue queue;
 108 } vlc_mutex_t;
 109
 110 typedef struct s_condition {
 111     spin_lock_t lock;
 112     struct cthread_queue queue;
 113     char *name;
 114     struct cond_imp *implications;
 115 } vlc_cond_t;
 116
 117 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 118 /* This is the BeOS implementation of the vlc threads, note that the mutex is
 119  * not a real mutex and the cond_var is not like a pthread cond_var but it is
 120  * enough for what wee need */
 121
 122 typedef thread_id vlc_thread_t;
 123
 124 typedef struct
 125 {
 126     int32           init;
 127     sem_id          lock;
 128 } vlc_mutex_t;
 129
 130 typedef struct
 131 {
 132     int32           init;
 133     thread_id       thread;
 134 } vlc_cond_t;
 135
 136 #elif defined( WIN32 )
 137 typedef HANDLE      vlc_thread_t;
 138 typedef HANDLE      vlc_mutex_t;
 139 typedef HANDLE      vlc_cond_t;
 140 typedef unsigned (__stdcall *PTHREAD_START) (void *);
 141
 142 #endif
 143
 144 typedef void *(*vlc_thread_func_t)(void *p_data);
 145
 146 /*****************************************************************************
 147  * Prototypes
 148  *****************************************************************************/
 149
 150 static __inline__ int  vlc_threads_init  ( void );
 151 static __inline__ int  vlc_threads_end   ( void );
 152
 153 static __inline__ int  vlc_mutex_init    ( vlc_mutex_t * );
 154 static __inline__ int  vlc_mutex_lock    ( vlc_mutex_t * );
 155 static __inline__ int  vlc_mutex_unlock  ( vlc_mutex_t * );
 156 static __inline__ int  vlc_mutex_destroy ( vlc_mutex_t * );
 157
 158 static __inline__ int  vlc_cond_init     ( vlc_cond_t * );
 159 static __inline__ int  vlc_cond_signal   ( vlc_cond_t * );
 160 static __inline__ int  vlc_cond_wait     ( vlc_cond_t *, vlc_mutex_t * );
 161 static __inline__ int  vlc_cond_destroy  ( vlc_cond_t * );
 162
 163 static __inline__ int  vlc_thread_create ( vlc_thread_t *, char *,
 164                                            vlc_thread_func_t, void * );
 165 static __inline__ void vlc_thread_exit   ( void );
 166 static __inline__ void vlc_thread_join   ( vlc_thread_t );
 167
 168 #if 0
 169 static __inline__ int  vlc_cond_timedwait( vlc_cond_t *, vlc_mutex_t *,
 170                                            mtime_t );
 171 #endif
 172
 173 #ifdef PROFILING
 174 /* Wrapper function for profiling */
 175 static void *      vlc_thread_wrapper ( void *p_wrapper );
 176
 177 typedef struct wrapper_s
 178 {
 179     /* Data lock access */
 180     vlc_mutex_t lock;
 181     vlc_cond_t  wait;
 182
 183     /* Data used to spawn the real thread */
 184     vlc_thread_func_t func;
 185     void *p_data;
 186
 187     /* Profiling timer passed to the thread */
 188     struct itimerval itimer;
 189
 190 } wrapper_t;
 191 #endif
 192
 193 /*****************************************************************************
 194  * vlc_threads_init: initialize threads system
 195  *****************************************************************************/
 196 static __inline__ int vlc_threads_init( void )
 197 {
 198 #if defined( PTH_INIT_IN_PTH_H )
 199     return pth_init();
 200
 201 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 202     return 0;
 203
 204 #elif defined( HAVE_CTHREADS_H )
 205     return 0;
 206
 207 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 208     return 0;
 209
 210 #elif defined( WIN32 )
 211     return 0;
 212
 213 #endif
 214 }
 215
 216 /*****************************************************************************
 217  * vlc_threads_end: stop threads system
 218  *****************************************************************************/
 219 static __inline__ int vlc_threads_end( void )
 220 {
 221 #if defined( PTH_INIT_IN_PTH_H )
 222     return pth_kill();
 223
 224 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 225     return 0;
 226
 227 #elif defined( HAVE_CTHREADS_H )
 228     return 0;
 229
 230 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 231     return 0;
 232
 233 #elif defined( WIN32 )
 234     return 0;
 235
 236 #endif
 237 }
 238
 239 /*****************************************************************************
 240  * vlc_mutex_init: initialize a mutex
 241  *****************************************************************************/
 242 static __inline__ int vlc_mutex_init( vlc_mutex_t *p_mutex )
 243 {
 244 #if defined( PTH_INIT_IN_PTH_H )
 245     return pth_mutex_init( p_mutex );
 246
 247 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 248     return pthread_mutex_init( p_mutex, NULL );
 249
 250 #elif defined( HAVE_CTHREADS_H )
 251     mutex_init( p_mutex );
 252     return 0;
 253
 254 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 255
 256     /* check the arguments and whether it's already been initialized */
 257     if( p_mutex == NULL )
 258     {
 259         return B_BAD_VALUE;
 260     }
 261
 262     if( p_mutex->init == 9999 )
 263     {
 264         return EALREADY;
 265     }
 266
 267     p_mutex->lock = create_sem( 1, "BeMutex" );
 268     if( p_mutex->lock < B_NO_ERROR )
 269     {
 270         return( -1 );
 271     }
 272
 273     p_mutex->init = 9999;
 274     return B_OK;
 275
 276 #elif defined( WIN32 )
 277     *p_mutex = CreateMutex(0,FALSE,0);
 278     return (*p_mutex?0:1);
 279
 280 #endif
 281 }
 282
 283 /*****************************************************************************
 284  * vlc_mutex_lock: lock a mutex
 285  *****************************************************************************/
 286 static __inline__ int vlc_mutex_lock( vlc_mutex_t *p_mutex )
 287 {
 288 #if defined( PTH_INIT_IN_PTH_H )
 289     return pth_mutex_acquire( p_mutex, TRUE, NULL );
 290
 291 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 292     return pthread_mutex_lock( p_mutex );
 293
 294 #elif defined( HAVE_CTHREADS_H )
 295     mutex_lock( p_mutex );
 296     return 0;
 297
 298 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 299     status_t err;
 300
 301     if( !p_mutex )
 302     {
 303         return B_BAD_VALUE;
 304     }
 305
 306     if( p_mutex->init < 2000 )
 307     {
 308         return B_NO_INIT;
 309     }
 310
 311     err = acquire_sem( p_mutex->lock );
 312     return err;
 313
 314 #elif defined( WIN32 )
 315     WaitForSingleObject( *p_mutex, INFINITE );
 316     return 0;
 317
 318 #endif
 319 }
 320
 321 /*****************************************************************************
 322  * vlc_mutex_unlock: unlock a mutex
 323  *****************************************************************************/
 324 static __inline__ int vlc_mutex_unlock( vlc_mutex_t *p_mutex )
 325 {
 326 #if defined( PTH_INIT_IN_PTH_H )
 327     return pth_mutex_release( p_mutex );
 328
 329 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 330     return pthread_mutex_unlock( p_mutex );
 331
 332 #elif defined( HAVE_CTHREADS_H )
 333     mutex_unlock( p_mutex );
 334     return 0;
 335
 336 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 337     if( !p_mutex)
 338     {
 339         return B_BAD_VALUE;
 340     }
 341
 342     if( p_mutex->init < 2000 )
 343     {
 344         return B_NO_INIT;
 345     }
 346
 347     release_sem( p_mutex->lock );
 348     return B_OK;
 349
 350 #elif defined( WIN32 )
 351     ReleaseMutex( *p_mutex );
 352     return 0;
 353
 354 #endif
 355 }
 356
 357 /*****************************************************************************
 358  * vlc_mutex_destroy: destroy a mutex
 359  *****************************************************************************/
 360 static __inline__ int vlc_mutex_destroy( vlc_mutex_t *p_mutex )
 361 {
 362 #if defined( PTH_INIT_IN_PTH_H )
 363     return 0;
 364
 365 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 366     return pthread_mutex_destroy( p_mutex );
 367
 368 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 369     if( p_mutex->init == 9999 )
 370     {
 371         delete_sem( p_mutex->lock );
 372     }
 373
 374     p_mutex->init = 0;
 375     return B_OK;
 376
 377 #elif defined( WIN32 )
 378     CloseHandle(*p_mutex);
 379     return 0;
 380
 381 #endif
 382 }
 383
 384 /*****************************************************************************
 385  * vlc_cond_init: initialize a condition
 386  *****************************************************************************/
 387 static __inline__ int vlc_cond_init( vlc_cond_t *p_condvar )
 388 {
 389 #if defined( PTH_INIT_IN_PTH_H )
 390     return pth_cond_init( p_condvar );
 391
 392 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 393     return pthread_cond_init( p_condvar, NULL );
 394
 395 #elif defined( HAVE_CTHREADS_H )
 396     /* condition_init() */
 397     spin_lock_init( &p_condvar->lock );
 398     cthread_queue_init( &p_condvar->queue );
 399     p_condvar->name = 0;
 400     p_condvar->implications = 0;
 401
 402     return 0;
 403
 404 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 405     if( !p_condvar )
 406     {
 407         return B_BAD_VALUE;
 408     }
 409
 410     if( p_condvar->init == 9999 )
 411     {
 412         return EALREADY;
 413     }
 414
 415     p_condvar->thread = -1;
 416     p_condvar->init = 9999;
 417     return 0;
 418
 419 #elif defined( WIN32 )
 420     /* Create an auto-reset event. */
 421     *p_condvar = CreateEvent( NULL,   /* no security */
 422                               FALSE,  /* auto-reset event */
 423                               FALSE,  /* non-signaled initially */
 424                               NULL ); /* unnamed */
 425
 426     return( *p_condvar ? 0 : 1 );
 427
 428 #endif
 429 }
 430
 431 /*****************************************************************************
 432  * vlc_cond_signal: start a thread on condition completion
 433  *****************************************************************************/
 434 static __inline__ int vlc_cond_signal( vlc_cond_t *p_condvar )
 435 {
 436 #if defined( PTH_INIT_IN_PTH_H )
 437     return pth_cond_notify( p_condvar, FALSE );
 438
 439 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 440     return pthread_cond_signal( p_condvar );
 441
 442 #elif defined( HAVE_CTHREADS_H )
 443     /* condition_signal() */
 444     if ( p_condvar->queue.head || p_condvar->implications )
 445     {
 446         cond_signal( (condition_t)p_condvar );
 447     }
 448     return 0;
 449
 450 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 451     if( !p_condvar )
 452     {
 453         return B_BAD_VALUE;
 454     }
 455
 456     if( p_condvar->init < 2000 )
 457     {
 458         return B_NO_INIT;
 459     }
 460
 461     while( p_condvar->thread != -1 )
 462     {
 463         thread_info info;
 464         if( get_thread_info(p_condvar->thread, &info) == B_BAD_VALUE )
 465         {
 466             return 0;
 467         }
 468
 469         if( info.state != B_THREAD_SUSPENDED )
 470         {
 471             /* The  waiting thread is not suspended so it could
 472              * have been interrupted beetwen the unlock and the
 473              * suspend_thread line. That is why we sleep a little
 474              * before retesting p_condver->thread. */
 475             snooze( 10000 );
 476         }
 477         else
 478         {
 479             /* Ok, we have to wake up that thread */
 480             resume_thread( p_condvar->thread );
 481             return 0;
 482         }
 483     }
 484     return 0;
 485
 486 #elif defined( WIN32 )
 487     /* Try to release one waiting thread. */
 488     PulseEvent ( *p_condvar );
 489     return 0;
 490
 491 #endif
 492 }
 493
 494 /*****************************************************************************
 495  * vlc_cond_wait: wait until condition completion
 496  *****************************************************************************/
 497 static __inline__ int vlc_cond_wait( vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex )
 498 {
 499 #if defined( PTH_INIT_IN_PTH_H )
 500     return pth_cond_await( p_condvar, p_mutex, NULL );
 501
 502 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 503     return pthread_cond_wait( p_condvar, p_mutex );
 504
 505 #elif defined( HAVE_CTHREADS_H )
 506     condition_wait( (condition_t)p_condvar, (mutex_t)p_mutex );
 507     return 0;
 508
 509 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 510     if( !p_condvar )
 511     {
 512         return B_BAD_VALUE;
 513     }
 514
 515     if( !p_mutex )
 516     {
 517         return B_BAD_VALUE;
 518     }
 519
 520     if( p_condvar->init < 2000 )
 521     {
 522         return B_NO_INIT;
 523     }
 524
 525     /* The p_condvar->thread var is initialized before the unlock because
 526      * it enables to identify when the thread is interrupted beetwen the
 527      * unlock line and the suspend_thread line */
 528     p_condvar->thread = find_thread( NULL );
 529     vlc_mutex_unlock( p_mutex );
 530     suspend_thread( p_condvar->thread );
 531     p_condvar->thread = -1;
 532
 533     vlc_mutex_lock( p_mutex );
 534     return 0;
 535
 536 #elif defined( WIN32 )
 537     /* Release the <external_mutex> here and wait for the event
 538      * to become signaled, due to <pthread_cond_signal> being
 539      * called. */
 540     vlc_mutex_unlock( p_mutex );
 541
 542     WaitForSingleObject( *p_condvar, INFINITE );
 543
 544     /* Reacquire the mutex before returning. */
 545     vlc_mutex_lock( p_mutex );
 546     return 0;
 547
 548 #endif
 549 }
 550
 551 /*****************************************************************************
 552  * vlc_cond_destroy: destroy a condition
 553  *****************************************************************************/
 554 static __inline__ int vlc_cond_destroy( vlc_cond_t *p_condvar )
 555 {
 556 #if defined( PTH_INIT_IN_PTH_H )
 557     return 0;
 558
 559 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 560     return pthread_cond_destroy( p_condvar );
 561
 562 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 563     p_condvar->init = 0;
 564     return 0;
 565
 566 #elif defined( WIN32 )
 567     CloseHandle( *p_condvar );
 568     return 0;
 569
 570 #endif
 571 }
 572
 573 /*****************************************************************************
 574  * vlc_thread_create: create a thread
 575  *****************************************************************************/
 576 static __inline__ int vlc_thread_create( vlc_thread_t *p_thread,
 577                                          char *psz_name, vlc_thread_func_t func,
 578                                          void *p_data )
 579 {
 580     int i_ret;
 581
 582 #ifdef PROFILING
 583     wrapper_t wrapper;
 584
 585     /* Initialize the wrapper structure */
 586     wrapper.func = func;
 587     wrapper.p_data = p_data;
 588     getitimer( ITIMER_PROF, &wrapper.itimer );
 589     vlc_mutex_init( &wrapper.lock );
 590     vlc_cond_init( &wrapper.wait );
 591     vlc_mutex_lock( &wrapper.lock );
 592
 593     /* Alter user-passed data so that we call the wrapper instead
 594      * of the real function */
 595     p_data = &wrapper;
 596     func = vlc_thread_wrapper;
 597 #endif
 598
 599 #if defined( PTH_INIT_IN_PTH_H )
 600     *p_thread = pth_spawn( PTH_ATTR_DEFAULT, func, p_data );
 601     i_ret = ( p_thread == NULL );
 602
 603 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 604     i_ret = pthread_create( p_thread, NULL, func, p_data );
 605
 606 #elif defined( HAVE_CTHREADS_H )
 607     *p_thread = cthread_fork( (cthread_fn_t)func, (any_t)p_data );
 608     i_ret = 0;
 609
 610 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 611     *p_thread = spawn_thread( (thread_func)func, psz_name,
 612                               B_NORMAL_PRIORITY, p_data );
 613     i_ret = resume_thread( *p_thread );
 614
 615 #elif defined( WIN32 )
 616 #if 0
 617     DWORD threadID;
 618     /* This method is not recommended when using the MSVCRT C library,
 619      * so we'll have to use _beginthreadex instead */
 620     *p_thread = CreateThread(0, 0, (LPTHREAD_START_ROUTINE) func,
 621                              p_data, 0, &threadID);
 622 #endif
 623     unsigned threadID;
 624     /* When using the MSVCRT C library you have to use the _beginthreadex
 625      * function instead of CreateThread, otherwise you'll end up with memory
 626      * leaks and the signal function not working */
 627     *p_thread = (HANDLE)_beginthreadex(NULL, 0, (PTHREAD_START) func,
 628                              p_data, 0, &threadID);
 629
 630     i_ret = ( *p_thread ? 0 : 1 );
 631
 632 #endif
 633
 634 #ifdef PROFILING
 635     if( i_ret == 0 )
 636     {
 637         vlc_cond_wait( &wrapper.wait, &wrapper.lock );
 638     }
 639
 640     vlc_mutex_unlock( &wrapper.lock );
 641     vlc_mutex_destroy( &wrapper.lock );
 642     vlc_cond_destroy( &wrapper.wait );
 643 #endif
 644
 645     return i_ret;
 646 }
 647
 648 /*****************************************************************************
 649  * vlc_thread_exit: terminate a thread
 650  *****************************************************************************/
 651 static __inline__ void vlc_thread_exit( void )
 652 {
 653 #if defined( PTH_INIT_IN_PTH_H )
 654     pth_exit( 0 );
 655
 656 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 657     pthread_exit( 0 );
 658
 659 #elif defined( HAVE_CTHREADS_H )
 660     int result;
 661     cthread_exit( &result );
 662
 663 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 664     exit_thread( 0 );
 665
 666 #elif defined( WIN32 )
 667 #if 0
 668     ExitThread( 0 );
 669 #endif
 670     /* For now we don't close the thread handles (because of race conditions).
 671      * Need to be looked at. */
 672     _endthreadex(0);
 673
 674 #endif
 675 }
 676
 677 /*****************************************************************************
 678  * vlc_thread_join: wait until a thread exits
 679  *****************************************************************************/
 680 static __inline__ void vlc_thread_join( vlc_thread_t thread )
 681 {
 682 #if defined( PTH_INIT_IN_PTH_H )
 683     pth_join( thread, NULL );
 684
 685 #elif defined( PTHREAD_COND_T_IN_PTHREAD_H )
 686     pthread_join( thread, NULL );
 687
 688 #elif defined( HAVE_CTHREADS_H )
 689     cthread_join( thread );
 690
 691 #elif defined( HAVE_KERNEL_SCHEDULER_H )
 692     int32 exit_value;
 693     wait_for_thread( thread, &exit_value );
 694
 695 #elif defined( WIN32 )
 696     WaitForSingleObject( thread, INFINITE);
 697
 698 #endif
 699 }
 700
 701 #ifdef PROFILING
 702 static void *vlc_thread_wrapper( void *p_wrapper )
 703 {
 704     /* Put user data in thread-local variables */
 705     void *            p_data = ((wrapper_t*)p_wrapper)->p_data;
 706     vlc_thread_func_t func   = ((wrapper_t*)p_wrapper)->func;
 707
 708     /* Set the profile timer value */
 709     setitimer( ITIMER_PROF, &((wrapper_t*)p_wrapper)->itimer, NULL );
 710
 711     /* Tell the calling thread that we don't need its data anymore */
 712     vlc_mutex_lock( &((wrapper_t*)p_wrapper)->lock );
 713     vlc_cond_signal( &((wrapper_t*)p_wrapper)->wait );
 714     vlc_mutex_unlock( &((wrapper_t*)p_wrapper)->lock );
 715
 716     /* Call the real function */
 717     return func( p_data );
 718 }
 719 #endif
 720