src/mac/carbon/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        thread.cpp
   3 // Purpose:     wxThread Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux
   5 // Modified by: Vadim Zeitlin to make it work :-)
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998),
   9 //                  Vadim Zeitlin (1999)
  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 <stdio.h>
  35
  36 #include <windows.h>
  37
  38 #include "wx/module.h"
  39 #include "wx/thread.h"
  40
  41 // the possible states of the thread ("=>" shows all possible transitions from
  42 // this state)
  43 enum wxThreadState
  44 {
  45     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  46     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  47     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  48     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
  49     STATE_EXITED        // thread is terminating
  50 };
  51
  52 // ----------------------------------------------------------------------------
  53 // static variables
  54 // ----------------------------------------------------------------------------
  55
  56 // if it's FALSE, some secondary thread is holding the GUI lock
  57 static bool s_bGuiOwnedByMainThread = TRUE;
  58
  59 // critical section which controls access to all GUI functions: any secondary
  60 // thread (i.e. except the main one) must enter this crit section before doing
  61 // any GUI calls
  62 static wxCriticalSection *s_critsectGui = NULL;
  63
  64 // critical section which protects s_nWaitingForGui variable
  65 static wxCriticalSection *s_critsectWaitingForGui = NULL;
  66
  67 // number of threads waiting for GUI in wxMutexGuiEnter()
  68 static size_t s_nWaitingForGui = 0;
  69
  70 // are we waiting for a thread termination?
  71 static bool s_waitingForThread = FALSE;
  72
  73 // ============================================================================
  74 // Windows implementation of thread classes
  75 // ============================================================================
  76
  77 // ----------------------------------------------------------------------------
  78 // wxMutex implementation
  79 // ----------------------------------------------------------------------------
  80 class wxMutexInternal
  81 {
  82 public:
  83    Handle p_mutex;
  84 };
  85
  86 wxMutex::wxMutex()
  87 {
  88     p_internal = new wxMutexInternal;
  89 //    p_internal->p_mutex = CreateMutex(NULL, FALSE, NULL);
  90     if ( !p_internal->p_mutex )
  91     {
  92         wxLogSysError(_("Can not create mutex."));
  93     }
  94
  95     m_locked = 0;
  96 }
  97
  98 wxMutex::~wxMutex()
  99 {
 100     if (m_locked > 0)
 101         wxLogDebug(wxT("Warning: freeing a locked mutex (%d locks)."), m_locked);
 102 //    CloseHandle(p_internal->p_mutex);
 103 }
 104
 105 wxMutexError wxMutex::Lock()
 106 {
 107 /*
 108     DWORD ret;
 109
 110     ret = WaitForSingleObject(p_internal->p_mutex, INFINITE);
 111     switch ( ret )
 112     {
 113         case WAIT_ABANDONED:
 114             return wxMUTEX_BUSY;
 115
 116         case WAIT_OBJECT_0:
 117             // ok
 118             break;
 119
 120         case WAIT_FAILED:
 121             wxLogSysError(_("Couldn't acquire a mutex lock"));
 122             return wxMUTEX_MISC_ERROR;
 123
 124         case WAIT_TIMEOUT:
 125         default:
 126             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 127     }
 128 */
 129     m_locked++;
 130     return wxMUTEX_NO_ERROR;
 131 }
 132
 133 wxMutexError wxMutex::TryLock()
 134 {
 135 /*
 136     DWORD ret;
 137
 138     ret = WaitForSingleObject(p_internal->p_mutex, 0);
 139     if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED)
 140         return wxMUTEX_BUSY;
 141
 142     m_locked++;
 143 */
 144     return wxMUTEX_NO_ERROR;
 145 }
 146
 147 wxMutexError wxMutex::Unlock()
 148 {
 149     if (m_locked > 0)
 150         m_locked--;
 151 /*
 152     BOOL ret = ReleaseMutex(p_internal->p_mutex);
 153     if ( ret == 0 )
 154     {
 155         wxLogSysError(_("Couldn't release a mutex"));
 156         return wxMUTEX_MISC_ERROR;
 157     }
 158 */
 159     return wxMUTEX_NO_ERROR;
 160 }
 161
 162 // ----------------------------------------------------------------------------
 163 // wxCondition implementation
 164 // ----------------------------------------------------------------------------
 165
 166 class wxConditionInternal
 167 {
 168 public:
 169     Handle event;
 170     int waiters;
 171 };
 172
 173 wxCondition::wxCondition()
 174 {
 175     p_internal = new wxConditionInternal;
 176 //    p_internal->event = CreateEvent(NULL, FALSE, FALSE, NULL);
 177     if ( !p_internal->event )
 178     {
 179         wxLogSysError(_("Can not create event object."));
 180     }
 181
 182     p_internal->waiters = 0;
 183 }
 184
 185 wxCondition::~wxCondition()
 186 {
 187 //    CloseHandle(p_internal->event);
 188 }
 189
 190 void wxCondition::Wait(wxMutex& mutex)
 191 {
 192     mutex.Unlock();
 193     p_internal->waiters++;
 194 //    WaitForSingleObject(p_internal->event, INFINITE);
 195     p_internal->waiters--;
 196     mutex.Lock();
 197 }
 198
 199 bool wxCondition::Wait(wxMutex& mutex,
 200                        unsigned long sec,
 201                        unsigned long nsec)
 202 {
 203 //    DWORD ret;
 204
 205     mutex.Unlock();
 206     p_internal->waiters++;
 207  //   ret = WaitForSingleObject(p_internal->event, (sec*1000)+(nsec/1000000));
 208     p_internal->waiters--;
 209     mutex.Lock();
 210
 211     return TRUE; // false for timeout
 212 }
 213
 214 void wxCondition::Signal()
 215 {
 216 //    SetEvent(p_internal->event);
 217 }
 218
 219 void wxCondition::Broadcast()
 220 {
 221     int i;
 222
 223     for (i=0;i<p_internal->waiters;i++)
 224     {
 225 //        if ( SetEvent(p_internal->event) == 0 )
 226         {
 227             wxLogSysError(_("Couldn't change the state of event object."));
 228         }
 229     }
 230 }
 231
 232 // ----------------------------------------------------------------------------
 233 // wxCriticalSection implementation
 234 // ----------------------------------------------------------------------------
 235
 236 class wxCriticalSectionInternal
 237 {
 238 public:
 239     // init the critical section object
 240     wxCriticalSectionInternal()
 241         { /* ::InitializeCriticalSection(&m_data);*/ }
 242
 243     // implicit cast to the associated data
 244     operator Handle *() { return &m_data; }
 245
 246     // free the associated ressources
 247     ~wxCriticalSectionInternal()
 248         { /* ::DeleteCriticalSection(&m_data); */}
 249
 250 private:
 251     Handle m_data;
 252 };
 253
 254 wxCriticalSection::wxCriticalSection()
 255 {
 256     m_critsect = new wxCriticalSectionInternal;
 257 }
 258
 259 wxCriticalSection::~wxCriticalSection()
 260 {
 261     delete m_critsect;
 262 }
 263
 264 void wxCriticalSection::Enter()
 265 {
 266 //    ::EnterCriticalSection(*m_critsect);
 267 }
 268
 269 void wxCriticalSection::Leave()
 270 {
 271 //    ::LeaveCriticalSection(*m_critsect);
 272 }
 273
 274 // ----------------------------------------------------------------------------
 275 // wxThread implementation
 276 // ----------------------------------------------------------------------------
 277
 278 // wxThreadInternal class
 279 // ----------------------
 280
 281 /*
 282 class wxThreadInternal
 283 {
 284 public:
 285     wxThreadInternal()
 286     {
 287         m_hThread = 0;
 288         m_state = STATE_NEW;
 289         m_priority = WXTHREAD_DEFAULT_PRIORITY;
 290     }
 291
 292     // create a new (suspended) thread (for the given thread object)
 293     bool Create(wxThread *thread);
 294
 295     // suspend/resume/terminate
 296     bool Suspend();
 297     bool Resume();
 298     void Cancel() { m_state = STATE_CANCELED; }
 299
 300     // thread state
 301     void SetState(wxThreadState state) { m_state = state; }
 302     wxThreadState GetState() const { return m_state; }
 303
 304     // thread priority
 305     void SetPriority(unsigned int priority) { m_priority = priority; }
 306     unsigned int GetPriority() const { return m_priority; }
 307
 308     // thread handle and id
 309     HANDLE GetHandle() const { return m_hThread; }
 310     DWORD  GetId() const { return m_tid; }
 311
 312     // thread function
 313     static DWORD WinThreadStart(wxThread *thread);
 314
 315 private:
 316     Handle        m_hThread;    // handle of the thread
 317     wxThreadState m_state;      // state, see wxThreadState enum
 318     unsigned int  m_priority;   // thread priority in "wx" units
 319     ThreadId         m_tid;        // thread id
 320 };
 321
 322 DWORD wxThreadInternal::WinThreadStart(wxThread *thread)
 323 {
 324     // store the thread object in the TLS
 325     if ( !::TlsSetValue(s_tlsThisThread, thread) )
 326     {
 327         wxLogSysError(_("Can not start thread: error writing TLS."));
 328
 329         return (DWORD)-1;
 330     }
 331
 332     DWORD ret = (DWORD)thread->Entry();
 333     thread->p_internal->SetState(STATE_EXITED);
 334     thread->OnExit();
 335
 336     delete thread;
 337
 338     return ret;
 339 }
 340
 341 bool wxThreadInternal::Create(wxThread *thread)
 342 {
 343     m_hThread = ::CreateThread
 344                   (
 345                     NULL,                               // default security
 346                     0,                                  // default stack size
 347                     (LPTHREAD_START_ROUTINE)            // thread entry point
 348                     wxThreadInternal::WinThreadStart,   //
 349                     (LPVOID)thread,                     // parameter
 350                     CREATE_SUSPENDED,                   // flags
 351                     &m_tid                              // [out] thread id
 352                   );
 353
 354     if ( m_hThread == NULL )
 355     {
 356         wxLogSysError(_("Can't create thread"));
 357
 358         return FALSE;
 359     }
 360
 361     // translate wxWindows priority to the Windows one
 362     int win_priority;
 363     if (m_priority <= 20)
 364         win_priority = THREAD_PRIORITY_LOWEST;
 365     else if (m_priority <= 40)
 366         win_priority = THREAD_PRIORITY_BELOW_NORMAL;
 367     else if (m_priority <= 60)
 368         win_priority = THREAD_PRIORITY_NORMAL;
 369     else if (m_priority <= 80)
 370         win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
 371     else if (m_priority <= 100)
 372         win_priority = THREAD_PRIORITY_HIGHEST;
 373     else
 374     {
 375         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 376         win_priority = THREAD_PRIORITY_NORMAL;
 377     }
 378
 379     if ( ::SetThreadPriority(m_hThread, win_priority) == 0 )
 380     {
 381         wxLogSysError(_("Can't set thread priority"));
 382     }
 383
 384     return TRUE;
 385 }
 386
 387 bool wxThreadInternal::Suspend()
 388 {
 389     DWORD nSuspendCount = ::SuspendThread(m_hThread);
 390     if ( nSuspendCount == (DWORD)-1 )
 391     {
 392         wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 393
 394         return FALSE;
 395     }
 396
 397     m_state = STATE_PAUSED;
 398
 399     return TRUE;
 400 }
 401
 402 bool wxThreadInternal::Resume()
 403 {
 404     DWORD nSuspendCount = ::ResumeThread(m_hThread);
 405     if ( nSuspendCount == (DWORD)-1 )
 406     {
 407         wxLogSysError(_("Can not resume thread %x"), m_hThread);
 408
 409         return FALSE;
 410     }
 411
 412     m_state = STATE_RUNNING;
 413
 414     return TRUE;
 415 }
 416
 417 // static functions
 418 // ----------------
 419
 420 wxThread *wxThread::This()
 421 {
 422     wxThread *thread = (wxThread *)::TlsGetValue(s_tlsThisThread);
 423
 424     // be careful, 0 may be a valid return value as well
 425     if ( !thread && (::GetLastError() != NO_ERROR) )
 426     {
 427         wxLogSysError(_("Couldn't get the current thread pointer"));
 428
 429         // return NULL...
 430     }
 431
 432     return thread;
 433 }
 434
 435 bool wxThread::IsMain()
 436 {
 437     return ::GetCurrentThreadId() == s_idMainThread;
 438 }
 439
 440 #ifdef Yield
 441     #undef Yield
 442 #endif
 443
 444 void wxThread::Yield()
 445 {
 446     // 0 argument to Sleep() is special
 447     ::Sleep(0);
 448 }
 449
 450 void wxThread::Sleep(unsigned long milliseconds)
 451 {
 452     ::Sleep(milliseconds);
 453 }
 454
 455 // create/start thread
 456 // -------------------
 457
 458 wxThreadError wxThread::Create()
 459 {
 460     if ( !p_internal->Create(this) )
 461         return wxTHREAD_NO_RESOURCE;
 462
 463     return wxTHREAD_NO_ERROR;
 464 }
 465
 466 wxThreadError wxThread::Run()
 467 {
 468     wxCriticalSectionLocker lock(m_critsect);
 469
 470     if ( p_internal->GetState() != STATE_NEW )
 471     {
 472         // actually, it may be almost any state at all, not only STATE_RUNNING
 473         return wxTHREAD_RUNNING;
 474     }
 475
 476     return Resume();
 477 }
 478
 479 // suspend/resume thread
 480 // ---------------------
 481
 482 wxThreadError wxThread::Pause()
 483 {
 484     wxCriticalSectionLocker lock(m_critsect);
 485
 486     return p_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 487 }
 488
 489 wxThreadError wxThread::Resume()
 490 {
 491     wxCriticalSectionLocker lock(m_critsect);
 492
 493     return p_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 494 }
 495
 496 // stopping thread
 497 // ---------------
 498
 499 wxThread::ExitCode wxThread::Delete()
 500 {
 501     ExitCode rc = 0;
 502
 503     // Delete() is always safe to call, so consider all possible states
 504     if ( IsPaused() )
 505         Resume();
 506
 507     if ( IsRunning() )
 508     {
 509         if ( IsMain() )
 510         {
 511             // set flag for wxIsWaitingForThread()
 512             s_waitingForThread = TRUE;
 513
 514             wxBeginBusyCursor();
 515         }
 516
 517         HANDLE hThread;
 518         {
 519             wxCriticalSectionLocker lock(m_critsect);
 520
 521             p_internal->Cancel();
 522             hThread = p_internal->GetHandle();
 523         }
 524
 525         // we can't just wait for the thread to terminate because it might be
 526         // calling some GUI functions and so it will never terminate before we
 527         // process the Windows messages that result from these functions
 528         DWORD result;
 529         do
 530         {
 531             result = ::MsgWaitForMultipleObjects
 532                      (
 533                        1,              // number of objects to wait for
 534                        &hThread,       // the objects
 535                        FALSE,          // don't wait for all objects
 536                        INFINITE,       // no timeout
 537                        QS_ALLEVENTS    // return as soon as there are any events
 538                      );
 539
 540             switch ( result )
 541             {
 542                 case 0xFFFFFFFF:
 543                     // error
 544                     wxLogSysError(_("Can not wait for thread termination"));
 545                     Kill();
 546                     return (ExitCode)-1;
 547
 548                 case WAIT_OBJECT_0:
 549                     // thread we're waiting for terminated
 550                     break;
 551
 552                 case WAIT_OBJECT_0 + 1:
 553                     // new message arrived, process it
 554                     if ( !wxTheApp->DoMessage() )
 555                     {
 556                         // WM_QUIT received: kill the thread
 557                         Kill();
 558
 559                         return (ExitCode)-1;
 560                     }
 561
 562                     if ( IsMain() )
 563                     {
 564                         // give the thread we're waiting for chance to exit
 565                         // from the GUI call it might have been in
 566                         if ( (s_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 567                         {
 568                             wxMutexGuiLeave();
 569                         }
 570                     }
 571
 572                     break;
 573
 574                 default:
 575                     wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
 576             }
 577         } while ( result != WAIT_OBJECT_0 );
 578
 579         if ( IsMain() )
 580         {
 581             s_waitingForThread = FALSE;
 582
 583             wxEndBusyCursor();
 584         }
 585
 586         if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
 587         {
 588             wxLogLastError("GetExitCodeThread");
 589
 590             rc = (ExitCode)-1;
 591         }
 592
 593         wxASSERT_MSG( (LPVOID)rc != (LPVOID)STILL_ACTIVE,
 594                       wxT("thread must be already terminated.") );
 595
 596         ::CloseHandle(hThread);
 597     }
 598
 599     return rc;
 600 }
 601
 602 wxThreadError wxThread::Kill()
 603 {
 604     if ( !IsRunning() )
 605         return wxTHREAD_NOT_RUNNING;
 606
 607     if ( !::TerminateThread(p_internal->GetHandle(), (DWORD)-1) )
 608     {
 609         wxLogSysError(_("Couldn't terminate thread"));
 610
 611         return wxTHREAD_MISC_ERROR;
 612     }
 613
 614     delete this;
 615
 616     return wxTHREAD_NO_ERROR;
 617 }
 618
 619 void wxThread::Exit(void *status)
 620 {
 621     delete this;
 622
 623     ::ExitThread((DWORD)status);
 624
 625     wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
 626 }
 627
 628 void wxThread::SetPriority(unsigned int prio)
 629 {
 630     wxCriticalSectionLocker lock(m_critsect);
 631
 632     p_internal->SetPriority(prio);
 633 }
 634
 635 unsigned int wxThread::GetPriority() const
 636 {
 637     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 638
 639     return p_internal->GetPriority();
 640 }
 641
 642 unsigned long wxThread::GetID() const
 643 {
 644     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 645
 646     return (unsigned long)p_internal->GetId();
 647 }
 648
 649 bool wxThread::IsRunning() const
 650 {
 651     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 652
 653     return p_internal->GetState() == STATE_RUNNING;
 654 }
 655
 656 bool wxThread::IsAlive() const
 657 {
 658     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 659
 660     return (p_internal->GetState() == STATE_RUNNING) ||
 661            (p_internal->GetState() == STATE_PAUSED);
 662 }
 663
 664 bool wxThread::IsPaused() const
 665 {
 666     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 667
 668     return (p_internal->GetState() == STATE_PAUSED);
 669 }
 670
 671 bool wxThread::TestDestroy()
 672 {
 673     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 674
 675     return p_internal->GetState() == STATE_CANCELED;
 676 }
 677
 678 wxThread::wxThread()
 679 {
 680     p_internal = new wxThreadInternal();
 681 }
 682
 683 wxThread::~wxThread()
 684 {
 685     delete p_internal;
 686 }
 687
 688 // ----------------------------------------------------------------------------
 689 // Automatic initialization for thread module
 690 // ----------------------------------------------------------------------------
 691
 692 class wxThreadModule : public wxModule
 693 {
 694 public:
 695     virtual bool OnInit();
 696     virtual void OnExit();
 697
 698 private:
 699     DECLARE_DYNAMIC_CLASS(wxThreadModule)
 700 };
 701
 702 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
 703
 704 bool wxThreadModule::OnInit()
 705 {
 706     // allocate TLS index for storing the pointer to the current thread
 707     s_tlsThisThread = ::TlsAlloc();
 708     if ( s_tlsThisThread == 0xFFFFFFFF )
 709     {
 710         // in normal circumstances it will only happen if all other
 711         // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
 712         // words, this should never happen
 713         wxLogSysError(_("Thread module initialization failed: "
 714                         "impossible to allocate index in thread "
 715                         "local storage"));
 716
 717         return FALSE;
 718     }
 719
 720     // main thread doesn't have associated wxThread object, so store 0 in the
 721     // TLS instead
 722     if ( !::TlsSetValue(s_tlsThisThread, (LPVOID)0) )
 723     {
 724         ::TlsFree(s_tlsThisThread);
 725         s_tlsThisThread = 0xFFFFFFFF;
 726
 727         wxLogSysError(_("Thread module initialization failed: "
 728                         "can not store value in thread local storage"));
 729
 730         return FALSE;
 731     }
 732
 733     s_critsectWaitingForGui = new wxCriticalSection();
 734
 735     s_critsectGui = new wxCriticalSection();
 736     s_critsectGui->Enter();
 737
 738     // no error return for GetCurrentThreadId()
 739     s_idMainThread = ::GetCurrentThreadId();
 740
 741     return TRUE;
 742 }
 743
 744 void wxThreadModule::OnExit()
 745 {
 746     if ( !::TlsFree(s_tlsThisThread) )
 747     {
 748         wxLogLastError("TlsFree failed.");
 749     }
 750
 751     if ( s_critsectGui )
 752     {
 753         s_critsectGui->Leave();
 754         delete s_critsectGui;
 755         s_critsectGui = NULL;
 756     }
 757
 758     wxDELETE(s_critsectWaitingForGui);
 759 }
 760
 761 // ----------------------------------------------------------------------------
 762 // under Windows, these functions are implemented usign a critical section and
 763 // not a mutex, so the names are a bit confusing
 764 // ----------------------------------------------------------------------------
 765
 766 void WXDLLEXPORT wxMutexGuiEnter()
 767 {
 768     // this would dead lock everything...
 769     wxASSERT_MSG( !wxThread::IsMain(),
 770                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
 771
 772     // the order in which we enter the critical sections here is crucial!!
 773
 774     // set the flag telling to the main thread that we want to do some GUI
 775     {
 776         wxCriticalSectionLocker enter(*s_critsectWaitingForGui);
 777
 778         s_nWaitingForGui++;
 779     }
 780
 781     wxWakeUpMainThread();
 782
 783     // now we may block here because the main thread will soon let us in
 784     // (during the next iteration of OnIdle())
 785     s_critsectGui->Enter();
 786 }
 787
 788 void WXDLLEXPORT wxMutexGuiLeave()
 789 {
 790     wxCriticalSectionLocker enter(*s_critsectWaitingForGui);
 791
 792     if ( wxThread::IsMain() )
 793     {
 794         s_bGuiOwnedByMainThread = FALSE;
 795     }
 796     else
 797     {
 798         // decrement the number of waiters now
 799         wxASSERT_MSG( s_nWaitingForGui > 0,
 800                       wxT("calling wxMutexGuiLeave() without entering it first?") );
 801
 802         s_nWaitingForGui--;
 803
 804         wxWakeUpMainThread();
 805     }
 806
 807     s_critsectGui->Leave();
 808 }
 809
 810 void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
 811 {
 812     wxASSERT_MSG( wxThread::IsMain(),
 813                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
 814
 815     wxCriticalSectionLocker enter(*s_critsectWaitingForGui);
 816
 817     if ( s_nWaitingForGui == 0 )
 818     {
 819         // no threads are waiting for GUI - so we may acquire the lock without
 820         // any danger (but only if we don't already have it)
 821         if ( !wxGuiOwnedByMainThread() )
 822         {
 823             s_critsectGui->Enter();
 824
 825             s_bGuiOwnedByMainThread = TRUE;
 826         }
 827         //else: already have it, nothing to do
 828     }
 829     else
 830     {
 831         // some threads are waiting, release the GUI lock if we have it
 832         if ( wxGuiOwnedByMainThread() )
 833         {
 834             wxMutexGuiLeave();
 835         }
 836         //else: some other worker thread is doing GUI
 837     }
 838 }
 839
 840 bool WXDLLEXPORT wxGuiOwnedByMainThread()
 841 {
 842     return s_bGuiOwnedByMainThread;
 843 }
 844
 845 // wake up the main thread if it's in ::GetMessage()
 846 void WXDLLEXPORT wxWakeUpMainThread()
 847 {
 848     // sending any message would do - hopefully WM_NULL is harmless enough
 849     if ( !::PostThreadMessage(s_idMainThread, WM_NULL, 0, 0) )
 850     {
 851         // should never happen
 852         wxLogLastError("PostThreadMessage(WM_NULL)");
 853     }
 854 }
 855
 856 bool WXDLLEXPORT wxIsWaitingForThread()
 857 {
 858     return s_waitingForThread;
 859 }
 860 */
 861
 862 #endif // wxUSE_THREADS