src/mac/carbon/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        thread.cpp
   3 // Purpose:     wxThread Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux/Vadim Zeitlin
   5 // Modified by: Stefan Csomor
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
   9 //                  Vadim Zeitlin (1999) , Stefan Csomor (2000)
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifdef __GNUG__
  14     #pragma implementation "thread.h"
  15 #endif
  16
  17 // ----------------------------------------------------------------------------
  18 // headers
  19 // ----------------------------------------------------------------------------
  20
  21 // For compilers that support precompilation, includes "wx.h".
  22 #include "wx/wxprec.h"
  23
  24 #if defined(__BORLANDC__)
  25     #pragma hdrstop
  26 #endif
  27
  28 #ifndef WX_PRECOMP
  29     #include "wx/wx.h"
  30 #endif
  31
  32 #if wxUSE_THREADS
  33
  34 #include "wx/module.h"
  35 #include "wx/thread.h"
  36
  37 #ifdef __WXMAC__
  38 #include "wx/mac/uma.h"
  39 #endif
  40
  41 // ----------------------------------------------------------------------------
  42 // constants
  43 // ----------------------------------------------------------------------------
  44
  45 // the possible states of the thread ("=>" shows all possible transitions from
  46 // this state)
  47 enum wxThreadState
  48 {
  49     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  50     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  51     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  52     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
  53     STATE_EXITED        // thread is terminating
  54 };
  55
  56 // ----------------------------------------------------------------------------
  57 // this module globals
  58 // ----------------------------------------------------------------------------
  59
  60 static ThreadID gs_idMainThread = kNoThreadID ;
  61 static bool gs_waitingForThread = FALSE ;
  62
  63 // ============================================================================
  64 // MacOS implementation of thread classes
  65 // ============================================================================
  66
  67 class wxMacStCritical
  68 {
  69 public :
  70     wxMacStCritical()
  71     {
  72         if ( UMASystemIsInitialized() )
  73             ThreadBeginCritical() ;
  74     }
  75     ~wxMacStCritical()
  76     {
  77         if ( UMASystemIsInitialized() )
  78             ThreadEndCritical() ;
  79     }
  80 };
  81
  82 // ----------------------------------------------------------------------------
  83 // wxMutex implementation
  84 // ----------------------------------------------------------------------------
  85
  86 class wxMutexInternal
  87 {
  88 public:
  89     wxMutexInternal()
  90     {
  91         m_owner = kNoThreadID ;
  92     }
  93
  94     ~wxMutexInternal()
  95     {
  96     }
  97
  98 public:
  99     ThreadID m_owner ;
 100     wxArrayLong m_waiters ;
 101 };
 102
 103 wxMutex::wxMutex()
 104 {
 105     m_internal = new wxMutexInternal;
 106
 107     m_locked = 0;
 108 }
 109
 110 wxMutex::~wxMutex()
 111 {
 112     if ( m_locked > 0 )
 113     {
 114         wxLogDebug(_T("Warning: freeing a locked mutex (%d locks)."), m_locked);
 115     }
 116
 117     delete m_internal;
 118 }
 119
 120 wxMutexError wxMutex::Lock()
 121 {
 122     wxMacStCritical critical ;
 123     if ( UMASystemIsInitialized() )
 124     {
 125         OSErr err ;
 126         ThreadID current = kNoThreadID;
 127         err = ::MacGetCurrentThread(&current);
 128         // if we are not the owner, add this thread to the list of waiting threads, stop this thread
 129         // and invoke the scheduler to continue executing the owner's thread
 130         while ( m_internal->m_owner != kNoThreadID && m_internal->m_owner != current)
 131         {
 132             m_internal->m_waiters.Add(current);
 133             err = ::SetThreadStateEndCritical(kCurrentThreadID, kStoppedThreadState, m_internal->m_owner);
 134             err = ::ThreadBeginCritical();
 135         }
 136         m_internal->m_owner = current;
 137     }
 138     m_locked++;
 139
 140     return wxMUTEX_NO_ERROR;
 141 }
 142
 143 wxMutexError wxMutex::TryLock()
 144 {
 145     wxMacStCritical critical ;
 146     if ( UMASystemIsInitialized() )
 147     {
 148         OSErr err ;
 149         ThreadID current = kNoThreadID;
 150         ::MacGetCurrentThread(&current);
 151         // if we are not the owner, give an error back
 152         if ( m_internal->m_owner != kNoThreadID && m_internal->m_owner != current )
 153             return wxMUTEX_BUSY;
 154
 155         m_internal->m_owner = current;
 156     }
 157     m_locked++;
 158
 159    return wxMUTEX_NO_ERROR;
 160 }
 161
 162 wxMutexError wxMutex::Unlock()
 163 {
 164     if ( UMASystemIsInitialized() )
 165     {
 166         OSErr err;
 167         err = ::ThreadBeginCritical();
 168
 169         if (m_locked > 0)
 170             m_locked--;
 171
 172         // this mutex is not owned by anybody anmore
 173         m_internal->m_owner = kNoThreadID;
 174
 175         // now pass on to the first waiting thread
 176         ThreadID firstWaiting = kNoThreadID;
 177         bool found = false;
 178         while (!m_internal->m_waiters.IsEmpty() && !found)
 179         {
 180             firstWaiting = m_internal->m_waiters[0];
 181             err = ::SetThreadState(firstWaiting, kReadyThreadState, kNoThreadID);
 182             // in case this was not successful (dead thread), we just loop on and reset the id
 183             found = (err != threadNotFoundErr);
 184             if ( !found )
 185                 firstWaiting = kNoThreadID ;
 186             m_internal->m_waiters.RemoveAt(0) ;
 187         }
 188         // now we have a valid firstWaiting thread, which has been scheduled to run next, just end the
 189         // critical section and invoke the scheduler
 190         err = ::SetThreadStateEndCritical(kCurrentThreadID, kReadyThreadState, firstWaiting);
 191     }
 192     else
 193     {
 194         if (m_locked > 0)
 195             m_locked--;
 196     }
 197     return wxMUTEX_NO_ERROR;
 198 }
 199
 200 // ----------------------------------------------------------------------------
 201 // wxCondition implementation
 202 // ----------------------------------------------------------------------------
 203
 204 class wxConditionInternal
 205 {
 206 public:
 207     wxConditionInternal()
 208     {
 209         m_excessSignals = 0 ;
 210     }
 211     ~wxConditionInternal()
 212     {
 213     }
 214
 215     bool Wait(unsigned long msectimeout)
 216     {
 217         wxMacStCritical critical ;
 218         if ( m_excessSignals > 0 )
 219         {
 220             --m_excessSignals ;
 221             return TRUE ;
 222         }
 223         else if ( msectimeout == 0 )
 224         {
 225             return FALSE ;
 226         }
 227         else
 228         {
 229         }
 230         /*
 231         waiters++;
 232
 233         // FIXME this should be MsgWaitForMultipleObjects() as well probably
 234         DWORD rc = ::WaitForSingleObject(event, timeout);
 235
 236         waiters--;
 237
 238         return rc != WAIT_TIMEOUT;
 239         */
 240         return TRUE ;
 241     }
 242     void Signal()
 243     {
 244         wxMacStCritical critical ;
 245     }
 246
 247     wxArrayLong m_waiters ;
 248     wxInt32     m_excessSignals ;
 249 };
 250
 251 wxCondition::wxCondition()
 252 {
 253     m_internal = new wxConditionInternal;
 254 }
 255
 256 wxCondition::~wxCondition()
 257 {
 258     delete m_internal;
 259 }
 260
 261 void wxCondition::Wait()
 262 {
 263     (void)m_internal->Wait(0xFFFFFFFFL);
 264 }
 265
 266 bool wxCondition::Wait(unsigned long sec,
 267                        unsigned long nsec)
 268 {
 269     return m_internal->Wait(sec*1000 + nsec/1000000);
 270 }
 271
 272 void wxCondition::Signal()
 273 {
 274     // set the event to signaled: if a thread is already waiting on it, it will
 275     // be woken up, otherwise the event will remain in the signaled state until
 276     // someone waits on it. In any case, the system will return it to a non
 277     // signalled state afterwards. If multiple threads are waiting, only one
 278     // will be woken up.
 279     m_internal->Signal() ;
 280 }
 281
 282 void wxCondition::Broadcast()
 283 {
 284     // this works because all these threads are already waiting and so each
 285     // SetEvent() inside Signal() is really a PulseEvent() because the event
 286     // state is immediately returned to non-signaled
 287     for ( int i = 0; i < m_internal->m_waiters.Count(); i++ )
 288     {
 289         Signal();
 290     }
 291 }
 292
 293 // ----------------------------------------------------------------------------
 294 // wxCriticalSection implementation
 295 // ----------------------------------------------------------------------------
 296
 297 // it's implemented as a mutex on mac os, so it is defined in the headers
 298
 299 // ----------------------------------------------------------------------------
 300 // wxThread implementation
 301 // ----------------------------------------------------------------------------
 302
 303 // wxThreadInternal class
 304 // ----------------------
 305
 306 class wxThreadInternal
 307 {
 308 public:
 309     wxThreadInternal()
 310     {
 311         m_tid = kNoThreadID ;
 312         m_state = STATE_NEW;
 313         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 314     }
 315
 316     ~wxThreadInternal()
 317     {
 318     }
 319
 320     void Free()
 321     {
 322     }
 323
 324     // create a new (suspended) thread (for the given thread object)
 325     bool Create(wxThread *thread, unsigned int stackSize);
 326
 327     // suspend/resume/terminate
 328     bool Suspend();
 329     bool Resume();
 330     void Cancel() { m_state = STATE_CANCELED; }
 331
 332     // thread state
 333     void SetState(wxThreadState state) { m_state = state; }
 334     wxThreadState GetState() const { return m_state; }
 335
 336     // thread priority
 337     void SetPriority(unsigned int priority);
 338     unsigned int GetPriority() const { return m_priority; }
 339
 340     void SetResult( void *res ) { m_result = res ; }
 341     void *GetResult() { return m_result ; }
 342
 343     // thread handle and id
 344     ThreadID  GetId() const { return m_tid; }
 345
 346     // thread function
 347     static pascal void*    MacThreadStart(wxThread* arg);
 348
 349 private:
 350     wxThreadState           m_state;      // state, see wxThreadState enum
 351     unsigned int            m_priority;   // thread priority in "wx" units
 352     ThreadID                m_tid;        // thread id
 353     void*                   m_result;
 354     static ThreadEntryUPP   s_threadEntry ;
 355 };
 356
 357 static wxArrayPtrVoid s_threads ;
 358
 359 ThreadEntryUPP wxThreadInternal::s_threadEntry = NULL ;
 360 pascal void* wxThreadInternal::MacThreadStart(wxThread *thread)
 361 {
 362     // first of all, check whether we hadn't been cancelled already
 363     if ( thread->m_internal->GetState() == STATE_EXITED )
 364     {
 365         return (void*)-1;
 366     }
 367
 368     void* rc = thread->Entry();
 369
 370     // enter m_critsect before changing the thread state
 371     thread->m_critsect.Enter();
 372     bool wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
 373     thread->m_internal->SetState(STATE_EXITED);
 374     thread->m_critsect.Leave();
 375
 376     thread->OnExit();
 377
 378     // if the thread was cancelled (from Delete()), then it the handle is still
 379     // needed there
 380     if ( thread->IsDetached() && !wasCancelled )
 381     {
 382         // auto delete
 383         delete thread;
 384     }
 385     //else: the joinable threads handle will be closed when Wait() is done
 386
 387     return rc;
 388 }
 389 void wxThreadInternal::SetPriority(unsigned int priority)
 390 {
 391     // Priorities don't exist on Mac
 392 }
 393
 394 bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
 395 {
 396     if ( s_threadEntry == NULL )
 397     {
 398         s_threadEntry = NewThreadEntryUPP( (ThreadEntryProcPtr) MacThreadStart ) ;
 399     }
 400     OSErr err = NewThread( kCooperativeThread,
 401                            s_threadEntry,
 402                            (void*) thread,
 403                            stackSize,
 404                            kNewSuspend,
 405                            &m_result,
 406                            &m_tid );
 407
 408     if ( err != noErr )
 409     {
 410         wxLogSysError(_("Can't create thread"));
 411         return FALSE;
 412     }
 413
 414     if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
 415     {
 416         SetPriority(m_priority);
 417     }
 418
 419     return TRUE;
 420 }
 421
 422 bool wxThreadInternal::Suspend()
 423 {
 424     OSErr err ;
 425
 426     ::ThreadBeginCritical();
 427
 428     if ( m_state != STATE_RUNNING )
 429     {
 430         ::ThreadEndCritical() ;
 431         wxLogSysError(_("Can not suspend thread %x"), m_tid);
 432         return FALSE;
 433     }
 434
 435     m_state = STATE_PAUSED;
 436
 437     err = ::SetThreadStateEndCritical(m_tid, kStoppedThreadState, kNoThreadID);
 438
 439     return TRUE;
 440 }
 441
 442 bool wxThreadInternal::Resume()
 443 {
 444     ThreadID current ;
 445     OSErr err ;
 446     err = MacGetCurrentThread( &current ) ;
 447
 448     wxASSERT( err == noErr ) ;
 449     wxASSERT( current != m_tid ) ;
 450
 451     ::ThreadBeginCritical();
 452     if ( m_state != STATE_PAUSED && m_state != STATE_NEW )
 453     {
 454         ::ThreadEndCritical() ;
 455         wxLogSysError(_("Can not resume thread %x"), m_tid);
 456         return FALSE;
 457
 458     }
 459     err = ::SetThreadStateEndCritical(m_tid, kReadyThreadState, kNoThreadID);
 460     wxASSERT( err == noErr ) ;
 461
 462     m_state = STATE_RUNNING;
 463     ::ThreadEndCritical() ;
 464     ::YieldToAnyThread() ;
 465     return TRUE;
 466 }
 467
 468 // static functions
 469 // ----------------
 470 wxThread *wxThread::This()
 471 {
 472     wxMacStCritical critical ;
 473
 474     ThreadID current ;
 475     OSErr err ;
 476
 477     err = MacGetCurrentThread( &current ) ;
 478
 479     for ( int i = 0 ; i < s_threads.Count() ; ++i )
 480     {
 481         if ( ( (wxThread*) s_threads[i] )->GetId() == current )
 482             return (wxThread*) s_threads[i] ;
 483     }
 484
 485     wxLogSysError(_("Couldn't get the current thread pointer"));
 486     return NULL;
 487 }
 488
 489 bool wxThread::IsMain()
 490 {
 491     ThreadID current ;
 492     OSErr err ;
 493
 494     err = MacGetCurrentThread( &current ) ;
 495     return current == gs_idMainThread;
 496 }
 497
 498 #ifdef Yield
 499 #undef Yield
 500 #endif
 501
 502 void wxThread::Yield()
 503 {
 504     ::YieldToAnyThread() ;
 505 }
 506
 507 void wxThread::Sleep(unsigned long milliseconds)
 508 {
 509         clock_t start = clock() ;
 510         do
 511         {
 512             YieldToAnyThread() ;
 513         } while( clock() - start < milliseconds / CLOCKS_PER_SEC ) ;
 514 }
 515
 516 int wxThread::GetCPUCount()
 517 {
 518     // we will use whatever MP API will be used for the new MP Macs
 519     return 1;
 520 }
 521
 522 bool wxThread::SetConcurrency(size_t level)
 523 {
 524     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 525
 526     // ok only for the default one
 527     if ( level == 0 )
 528         return 0;
 529
 530     // how many CPUs have we got?
 531     if ( GetCPUCount() == 1 )
 532     {
 533         // don't bother with all this complicated stuff - on a single
 534         // processor system it doesn't make much sense anyhow
 535         return level == 1;
 536     }
 537
 538     return TRUE ;
 539 }
 540
 541 // ctor and dtor
 542 // -------------
 543
 544 wxThread::wxThread(wxThreadKind kind)
 545 {
 546     m_internal = new wxThreadInternal();
 547
 548     m_isDetached = kind == wxTHREAD_DETACHED;
 549     s_threads.Add( (void*) this ) ;
 550 }
 551
 552 wxThread::~wxThread()
 553 {
 554     s_threads.Remove( (void*) this ) ;
 555     delete m_internal;
 556 }
 557
 558 // create/start thread
 559 // -------------------
 560
 561 wxThreadError wxThread::Create(unsigned int stackSize)
 562 {
 563     wxCriticalSectionLocker lock(m_critsect);
 564
 565     if ( !m_internal->Create(this, stackSize) )
 566         return wxTHREAD_NO_RESOURCE;
 567
 568     return wxTHREAD_NO_ERROR;
 569 }
 570
 571 wxThreadError wxThread::Run()
 572 {
 573     wxCriticalSectionLocker lock(m_critsect);
 574
 575     if ( m_internal->GetState() != STATE_NEW )
 576     {
 577         // actually, it may be almost any state at all, not only STATE_RUNNING
 578         return wxTHREAD_RUNNING;
 579     }
 580
 581     // the thread has just been created and is still suspended - let it run
 582     return Resume();
 583 }
 584
 585 // suspend/resume thread
 586 // ---------------------
 587
 588 wxThreadError wxThread::Pause()
 589 {
 590     wxCriticalSectionLocker lock(m_critsect);
 591
 592     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 593 }
 594
 595 wxThreadError wxThread::Resume()
 596 {
 597     wxCriticalSectionLocker lock(m_critsect);
 598
 599     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 600 }
 601
 602 // stopping thread
 603 // ---------------
 604
 605 wxThread::ExitCode wxThread::Wait()
 606 {
 607     // although under MacOS we can wait for any thread, it's an error to
 608     // wait for a detached one in wxWin API
 609     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
 610                  _T("can't wait for detached thread") );
 611
 612     ExitCode rc = (ExitCode)-1;
 613
 614     (void)Delete(&rc);
 615
 616     m_internal->Free();
 617
 618     return rc;
 619 }
 620
 621 wxThreadError wxThread::Delete(ExitCode *pRc)
 622 {
 623     ExitCode rc = 0;
 624
 625     // Delete() is always safe to call, so consider all possible states
 626
 627     // has the thread started to run?
 628     bool shouldResume = FALSE;
 629
 630     {
 631         wxCriticalSectionLocker lock(m_critsect);
 632
 633         if ( m_internal->GetState() == STATE_NEW )
 634         {
 635             // WinThreadStart() will see it and terminate immediately
 636             m_internal->SetState(STATE_EXITED);
 637
 638             shouldResume = TRUE;
 639         }
 640     }
 641
 642     // is the thread paused?
 643     if ( shouldResume || IsPaused() )
 644         Resume();
 645
 646     // does is still run?
 647     if ( IsRunning() )
 648     {
 649         if ( IsMain() )
 650         {
 651             // set flag for wxIsWaitingForThread()
 652             gs_waitingForThread = TRUE;
 653
 654 #if wxUSE_GUI
 655             wxBeginBusyCursor();
 656 #endif // wxUSE_GUI
 657         }
 658
 659         // ask the thread to terminate
 660         {
 661             wxCriticalSectionLocker lock(m_critsect);
 662
 663             m_internal->Cancel();
 664         }
 665
 666 #if wxUSE_GUI
 667         // simply wait for the thread to terminate
 668         while( TestDestroy() )
 669         {
 670             ::YieldToAnyThread() ;
 671         }
 672 #else // !wxUSE_GUI
 673         // simply wait for the thread to terminate
 674         while( TestDestroy() )
 675         {
 676             ::YieldToAnyThread() ;
 677         }
 678 #endif // wxUSE_GUI/!wxUSE_GUI
 679
 680         if ( IsMain() )
 681         {
 682             gs_waitingForThread = FALSE;
 683
 684 #if wxUSE_GUI
 685             wxEndBusyCursor();
 686 #endif // wxUSE_GUI
 687         }
 688     }
 689
 690  //   if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
 691     {
 692         wxLogLastError("GetExitCodeThread");
 693
 694         rc = (ExitCode)-1;
 695     }
 696
 697     if ( IsDetached() )
 698     {
 699         // if the thread exits normally, this is done in WinThreadStart, but in
 700         // this case it would have been too early because
 701         // MsgWaitForMultipleObject() would fail if the therad handle was
 702         // closed while we were waiting on it, so we must do it here
 703         delete this;
 704     }
 705
 706  //   wxASSERT_MSG( (DWORD)rc != STILL_ACTIVE,
 707  //                 wxT("thread must be already terminated.") );
 708
 709     if ( pRc )
 710         *pRc = rc;
 711
 712     return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
 713 }
 714
 715 wxThreadError wxThread::Kill()
 716 {
 717     if ( !IsRunning() )
 718         return wxTHREAD_NOT_RUNNING;
 719
 720 //    if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
 721     {
 722         wxLogSysError(_("Couldn't terminate thread"));
 723
 724         return wxTHREAD_MISC_ERROR;
 725     }
 726
 727     m_internal->Free();
 728
 729     if ( IsDetached() )
 730     {
 731         delete this;
 732     }
 733
 734     return wxTHREAD_NO_ERROR;
 735 }
 736
 737 void wxThread::Exit(ExitCode status)
 738 {
 739     m_internal->Free();
 740
 741     if ( IsDetached() )
 742     {
 743         delete this;
 744     }
 745
 746     m_internal->SetResult( status ) ;
 747
 748 /*
 749 #if defined(__VISUALC__) || (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500))
 750     _endthreadex((unsigned)status);
 751 #else // !VC++
 752     ::ExitThread((DWORD)status);
 753 #endif // VC++/!VC++
 754 */
 755     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
 756 }
 757
 758 // priority setting
 759 // ----------------
 760
 761 // since all these calls are execute cooperatively we don't have to use the critical section
 762
 763 void wxThread::SetPriority(unsigned int prio)
 764 {
 765     m_internal->SetPriority(prio);
 766 }
 767
 768 unsigned int wxThread::GetPriority() const
 769 {
 770     return m_internal->GetPriority();
 771 }
 772
 773 unsigned long wxThread::GetId() const
 774 {
 775     return (unsigned long)m_internal->GetId();
 776 }
 777
 778 bool wxThread::IsRunning() const
 779 {
 780     return m_internal->GetState() == STATE_RUNNING;
 781 }
 782
 783 bool wxThread::IsAlive() const
 784 {
 785     return (m_internal->GetState() == STATE_RUNNING) ||
 786            (m_internal->GetState() == STATE_PAUSED);
 787 }
 788
 789 bool wxThread::IsPaused() const
 790 {
 791     return m_internal->GetState() == STATE_PAUSED;
 792 }
 793
 794 bool wxThread::TestDestroy()
 795 {
 796     return m_internal->GetState() == STATE_CANCELED;
 797 }
 798
 799 // ----------------------------------------------------------------------------
 800 // Automatic initialization for thread module
 801 // ----------------------------------------------------------------------------
 802
 803 class wxThreadModule : public wxModule
 804 {
 805 public:
 806     virtual bool OnInit();
 807     virtual void OnExit();
 808
 809 private:
 810     DECLARE_DYNAMIC_CLASS(wxThreadModule)
 811 };
 812
 813 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
 814
 815 bool wxThreadModule::OnInit()
 816 {
 817     long response;
 818     bool hasThreadManager ;
 819     hasThreadManager = Gestalt( gestaltThreadMgrAttr, &response) == noErr && response & 1;
 820 #if !TARGET_CARBON
 821 #if GENERATINGCFM
 822     // verify presence of shared library
 823     hasThreadManager = hasThreadManager && ((Ptr)NewThread != (Ptr)kUnresolvedCFragSymbolAddress);
 824 #endif
 825 #endif
 826     if ( !hasThreadManager )
 827     {
 828         wxMessageBox( "Error" , "Thread Support is not available on this System" , wxOK ) ;
 829         return FALSE ;
 830     }
 831
 832     // no error return for GetCurrentThreadId()
 833     MacGetCurrentThread( &gs_idMainThread ) ;
 834
 835     return TRUE;
 836 }
 837
 838 void wxThreadModule::OnExit()
 839 {
 840 }
 841
 842 // ----------------------------------------------------------------------------
 843 // under MacOS we don't have currently preemptive threads, so any thread may access
 844 // the GUI at any time
 845 // ----------------------------------------------------------------------------
 846
 847 void WXDLLEXPORT wxMutexGuiEnter()
 848 {
 849 }
 850
 851 void WXDLLEXPORT wxMutexGuiLeave()
 852 {
 853 }
 854
 855 void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
 856 {
 857 }
 858
 859 bool WXDLLEXPORT wxGuiOwnedByMainThread()
 860 {
 861     return false ;
 862 }
 863
 864 // wake up the main thread
 865 void WXDLLEXPORT wxWakeUpMainThread()
 866 {
 867     wxMacWakeUp() ;
 868 }
 869
 870 bool WXDLLEXPORT wxIsWaitingForThread()
 871 {
 872     return false ;
 873 }
 874
 875 #endif // wxUSE_THREADS
 876
 877 // vi:sts=4:sw=4:et