src/os2/thread.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/os2/thread.cpp
   3 // Purpose:     wxThread Implementation
   4 // Author:      Original from Wolfram Gloger/Guilhem Lavaux/David Webster
   5 // Modified by: Stefan Neis
   6 // Created:     04/22/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Stefan Neis (2003)
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ----------------------------------------------------------------------------
  13 // headers
  14 // ----------------------------------------------------------------------------
  15
  16 // For compilers that support precompilation, includes "wx.h".
  17 #include "wx/wxprec.h"
  18
  19 #if wxUSE_THREADS
  20
  21 #include "wx/thread.h"
  22
  23 #ifndef WX_PRECOMP
  24     #include "wx/intl.h"
  25     #include "wx/log.h"
  26     #include "wx/app.h"
  27     #include "wx/module.h"
  28 #endif //WX_PRECOMP
  29
  30 #include "wx/apptrait.h"
  31 #include "wx/utils.h"
  32
  33 #include <stdio.h>
  34
  35 #define INCL_DOSSEMAPHORES
  36 #define INCL_DOSPROCESS
  37 #define INCL_DOSMISC
  38 #define INCL_ERRORS
  39 #include <os2.h>
  40 #ifndef __EMX__
  41 #include <bseerr.h>
  42 #endif
  43 // the possible states of the thread ("=>" shows all possible transitions from
  44 // this state)
  45 enum wxThreadState
  46 {
  47     STATE_NEW,          // didn't start execution yet (=> RUNNING)
  48     STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
  49     STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
  50     STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
  51     STATE_EXITED        // thread is terminating
  52 };
  53
  54 // ----------------------------------------------------------------------------
  55 // this module's globals
  56 // ----------------------------------------------------------------------------
  57
  58 // id of the main thread - the one which can call GUI functions without first
  59 // calling wxMutexGuiEnter()
  60 static ULONG                        s_ulIdMainThread = 1;
  61 wxMutex*                            p_wxMainMutex;
  62
  63 // OS2 substitute for Tls pointer the current parent thread object
  64 wxThread*                           m_pThread;    // pointer to the wxWidgets thread object
  65
  66 // if it's false, some secondary thread is holding the GUI lock
  67 static bool gs_bGuiOwnedByMainThread = true;
  68
  69 // critical section which controls access to all GUI functions: any secondary
  70 // thread (i.e. except the main one) must enter this crit section before doing
  71 // any GUI calls
  72 static wxCriticalSection *gs_pCritsectGui = NULL;
  73
  74 // critical section which protects s_nWaitingForGui variable
  75 static wxCriticalSection *gs_pCritsectWaitingForGui = NULL;
  76
  77 // number of threads waiting for GUI in wxMutexGuiEnter()
  78 static size_t gs_nWaitingForGui = 0;
  79
  80 // are we waiting for a thread termination?
  81 static bool gs_bWaitingForThread = false;
  82
  83 // ============================================================================
  84 // OS/2 implementation of thread and related classes
  85 // ============================================================================
  86
  87 // ----------------------------------------------------------------------------
  88 // wxMutex implementation
  89 // ----------------------------------------------------------------------------
  90 class wxMutexInternal
  91 {
  92 public:
  93     wxMutexInternal(wxMutexType mutexType);
  94     ~wxMutexInternal();
  95
  96     bool IsOk() const { return m_vMutex != NULL; }
  97
  98     wxMutexError Lock() { return LockTimeout(SEM_INDEFINITE_WAIT); }
  99     wxMutexError Lock(unsigned long ms) { return LockTimeout(ms); }
 100     wxMutexError TryLock();
 101     wxMutexError Unlock();
 102
 103 private:
 104     wxMutexError LockTimeout(ULONG ulMilliseconds);
 105     HMTX                            m_vMutex;
 106 };
 107
 108 // all mutexes are "pseudo-"recursive under OS2 so we don't use mutexType
 109 // (Calls to DosRequestMutexSem and DosReleaseMutexSem can be nested, but
 110 //  the request count for a semaphore cannot exceed 65535. If an attempt is
 111 //  made to exceed this number, ERROR_TOO_MANY_SEM_REQUESTS is returned.)
 112 wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(eMutexType))
 113 {
 114     APIRET ulrc = ::DosCreateMutexSem(NULL, &m_vMutex, 0L, FALSE);
 115     if (ulrc != 0)
 116     {
 117         wxLogSysError(_("Can not create mutex."));
 118         m_vMutex = NULL;
 119     }
 120 }
 121
 122 wxMutexInternal::~wxMutexInternal()
 123 {
 124     if (m_vMutex)
 125     {
 126         if (::DosCloseMutexSem(m_vMutex))
 127             wxLogLastError(_T("DosCloseMutexSem(mutex)"));
 128     }
 129 }
 130
 131 wxMutexError wxMutexInternal::TryLock()
 132 {
 133     const wxMutexError rc = LockTimeout( SEM_IMMEDIATE_RETURN );
 134
 135     // we have a special return code for timeout in this case
 136     return rc == wxMUTEX_TIMEOUT ? wxMUTEX_BUSY : rc;
 137 }
 138
 139 wxMutexError wxMutexInternal::LockTimeout(ULONG ulMilliseconds)
 140 {
 141     APIRET                          ulrc;
 142
 143     ulrc = ::DosRequestMutexSem(m_vMutex, ulMilliseconds);
 144
 145     switch (ulrc)
 146     {
 147         case ERROR_TIMEOUT:
 148             return wxMUTEX_TIMEOUT;
 149         case ERROR_TOO_MANY_SEM_REQUESTS:
 150             return wxMUTEX_BUSY;
 151
 152         case NO_ERROR:
 153             // ok
 154             break;
 155
 156         case ERROR_INVALID_HANDLE:
 157         case ERROR_INTERRUPT:
 158         case ERROR_SEM_OWNER_DIED:
 159             wxLogSysError(_("Couldn't acquire a mutex lock"));
 160             return wxMUTEX_MISC_ERROR;
 161
 162         default:
 163             wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
 164             return wxMUTEX_MISC_ERROR;
 165      }
 166     return wxMUTEX_NO_ERROR;
 167 }
 168
 169 wxMutexError wxMutexInternal::Unlock()
 170 {
 171     APIRET                          ulrc;
 172
 173     ulrc = ::DosReleaseMutexSem(m_vMutex);
 174     if (ulrc != 0)
 175     {
 176         wxLogSysError(_("Couldn't release a mutex"));
 177         return wxMUTEX_MISC_ERROR;
 178     }
 179     return wxMUTEX_NO_ERROR;
 180 }
 181
 182 // --------------------------------------------------------------------------
 183 // wxSemaphore
 184 // --------------------------------------------------------------------------
 185
 186 // a trivial wrapper around OS2 event semaphore
 187 class wxSemaphoreInternal
 188 {
 189 public:
 190     wxSemaphoreInternal(int initialcount, int maxcount);
 191     ~wxSemaphoreInternal();
 192
 193     bool IsOk() const { return m_vEvent != NULL; }
 194
 195     wxSemaError Wait() { return WaitTimeout(SEM_INDEFINITE_WAIT); }
 196     wxSemaError TryWait() { return WaitTimeout(SEM_IMMEDIATE_RETURN); }
 197     wxSemaError WaitTimeout(unsigned long milliseconds);
 198
 199     wxSemaError Post();
 200
 201 private:
 202     HEV m_vEvent;
 203     HMTX m_vMutex;
 204     int m_count;
 205     int m_maxcount;
 206 };
 207
 208 wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 209 {
 210     APIRET ulrc;
 211     if ( maxcount == 0 )
 212     {
 213         // make it practically infinite
 214         maxcount = INT_MAX;
 215     }
 216
 217     m_count = initialcount;
 218     m_maxcount = maxcount;
 219     ulrc = ::DosCreateMutexSem(NULL, &m_vMutex, 0L, FALSE);
 220     if (ulrc != 0)
 221     {
 222         wxLogLastError(_T("DosCreateMutexSem()"));
 223         m_vMutex = NULL;
 224         m_vEvent = NULL;
 225         return;
 226     }
 227     ulrc = ::DosCreateEventSem(NULL, &m_vEvent, 0L, FALSE);
 228     if ( ulrc != 0)
 229     {
 230         wxLogLastError(_T("DosCreateEventSem()"));
 231         ::DosCloseMutexSem(m_vMutex);
 232         m_vMutex = NULL;
 233         m_vEvent = NULL;
 234     }
 235     if (initialcount)
 236         ::DosPostEventSem(m_vEvent);
 237 }
 238
 239 wxSemaphoreInternal::~wxSemaphoreInternal()
 240 {
 241     if ( m_vEvent )
 242     {
 243         if ( ::DosCloseEventSem(m_vEvent) )
 244         {
 245             wxLogLastError(_T("DosCloseEventSem(semaphore)"));
 246         }
 247         if ( ::DosCloseMutexSem(m_vMutex) )
 248         {
 249             wxLogLastError(_T("DosCloseMutexSem(semaphore)"));
 250         }
 251         else
 252             m_vEvent = NULL;
 253     }
 254 }
 255
 256 wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long ulMilliseconds)
 257 {
 258     APIRET ulrc;
 259     do {
 260         ulrc = ::DosWaitEventSem(m_vEvent, ulMilliseconds );
 261         switch ( ulrc )
 262         {
 263             case NO_ERROR:
 264                 break;
 265
 266             case ERROR_TIMEOUT:
 267                 if (ulMilliseconds == SEM_IMMEDIATE_RETURN)
 268                     return wxSEMA_BUSY;
 269                 else
 270                     return wxSEMA_TIMEOUT;
 271
 272             default:
 273                 wxLogLastError(_T("DosWaitEventSem(semaphore)"));
 274                 return wxSEMA_MISC_ERROR;
 275         }
 276         ulrc = :: DosRequestMutexSem(m_vMutex, ulMilliseconds);
 277         switch ( ulrc )
 278         {
 279             case NO_ERROR:
 280                 // ok
 281                 break;
 282
 283             case ERROR_TIMEOUT:
 284             case ERROR_TOO_MANY_SEM_REQUESTS:
 285                 if (ulMilliseconds == SEM_IMMEDIATE_RETURN)
 286                     return wxSEMA_BUSY;
 287                 else
 288                     return wxSEMA_TIMEOUT;
 289
 290             default:
 291                 wxFAIL_MSG(wxT("DosRequestMutexSem(mutex)"));
 292                 return wxSEMA_MISC_ERROR;
 293         }
 294         bool OK = false;
 295         if (m_count > 0)
 296         {
 297             m_count--;
 298             OK = true;
 299         }
 300         else
 301         {
 302             ULONG ulPostCount;
 303             ::DosResetEventSem(m_vEvent, &ulPostCount);
 304         }
 305         ::DosReleaseMutexSem(m_vMutex);
 306         if (OK)
 307             return wxSEMA_NO_ERROR;
 308     } while (ulMilliseconds == SEM_INDEFINITE_WAIT);
 309
 310     if (ulMilliseconds == SEM_IMMEDIATE_RETURN)
 311         return wxSEMA_BUSY;
 312     return wxSEMA_TIMEOUT;
 313 }
 314
 315 wxSemaError wxSemaphoreInternal::Post()
 316 {
 317     APIRET ulrc;
 318     ulrc = ::DosRequestMutexSem(m_vMutex, SEM_INDEFINITE_WAIT);
 319     if (ulrc != NO_ERROR)
 320         return wxSEMA_MISC_ERROR;
 321     bool OK = false;
 322     if (m_count < m_maxcount)
 323     {
 324         m_count++;
 325         ulrc = ::DosPostEventSem(m_vEvent);
 326         OK = true;
 327     }
 328     ::DosReleaseMutexSem(m_vMutex);
 329     if (!OK)
 330         return wxSEMA_OVERFLOW;
 331     if ( ulrc != NO_ERROR && ulrc != ERROR_ALREADY_POSTED )
 332     {
 333         wxLogLastError(_T("DosPostEventSem(semaphore)"));
 334
 335         return wxSEMA_MISC_ERROR;
 336     }
 337
 338     return wxSEMA_NO_ERROR;
 339 }
 340
 341 // ----------------------------------------------------------------------------
 342 // wxThread implementation
 343 // ----------------------------------------------------------------------------
 344
 345 // wxThreadInternal class
 346 // ----------------------
 347
 348 class wxThreadInternal
 349 {
 350 public:
 351     inline wxThreadInternal()
 352     {
 353         m_hThread = 0;
 354         m_eState = STATE_NEW;
 355         m_nPriority = WXTHREAD_DEFAULT_PRIORITY;
 356     }
 357
 358     ~wxThreadInternal()
 359     {
 360         m_hThread = 0;
 361     }
 362
 363     // create a new (suspended) thread (for the given thread object)
 364     bool Create( wxThread*    pThread
 365                 ,unsigned int uStackSize
 366                );
 367
 368     // suspend/resume/terminate
 369     bool Suspend();
 370     bool Resume();
 371     inline void Cancel() { m_eState = STATE_CANCELED; }
 372
 373     // thread state
 374     inline void SetState(wxThreadState eState) { m_eState = eState; }
 375     inline wxThreadState GetState() const { return m_eState; }
 376
 377     // thread priority
 378     void                SetPriority(unsigned int nPriority);
 379     inline unsigned int GetPriority() const { return m_nPriority; }
 380
 381     // thread handle and id
 382     inline TID GetHandle() const { return m_hThread; }
 383     TID  GetId() const { return m_hThread; }
 384
 385     // thread function
 386     static void OS2ThreadStart(void* pParam);
 387
 388 private:
 389     // Threads in OS/2 have only an ID, so m_hThread is both it's handle and ID
 390     // PM also has no real Tls mechanism to index pointers by so we'll just
 391     // keep track of the wxWidgets parent object here.
 392     TID                             m_hThread;    // handle and ID of the thread
 393     wxThreadState                   m_eState;     // state, see wxThreadState enum
 394     unsigned int                    m_nPriority;  // thread priority in "wx" units
 395 };
 396
 397 void wxThreadInternal::OS2ThreadStart( void * pParam )
 398 {
 399     DWORD dwRet;
 400     bool bWasCancelled;
 401
 402     wxThread *pThread = (wxThread *)pParam;
 403
 404     // first of all, wait for the thread to be started.
 405     pThread->m_critsect.Enter();
 406     pThread->m_critsect.Leave();
 407     // Now check whether we hadn't been cancelled already and don't
 408     // start the user code at all in this case.
 409     if ( pThread->m_internal->GetState() == STATE_EXITED )
 410     {
 411         dwRet = (DWORD)-1;
 412         bWasCancelled = true;
 413     }
 414     else // do run thread
 415     {
 416         wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
 417         unsigned long ulHab;
 418         if (traits)
 419             traits->InitializeGui(ulHab);
 420         dwRet = (DWORD)pThread->Entry();
 421         if (traits)
 422             traits->TerminateGui(ulHab);
 423
 424         // enter m_critsect before changing the thread state
 425         pThread->m_critsect.Enter();
 426
 427         bWasCancelled = pThread->m_internal->GetState() == STATE_CANCELED;
 428
 429         pThread->m_internal->SetState(STATE_EXITED);
 430         pThread->m_critsect.Leave();
 431     }
 432     pThread->OnExit();
 433
 434     // if the thread was cancelled (from Delete()), then it the handle is still
 435     // needed there
 436     if (pThread->IsDetached() && !bWasCancelled)
 437     {
 438         // auto delete
 439         delete pThread;
 440     }
 441     //else: the joinable threads handle will be closed when Wait() is done
 442     return;
 443 }
 444
 445 void wxThreadInternal::SetPriority(
 446   unsigned int                      nPriority
 447 )
 448 {
 449     // translate wxWidgets priority to the PM one
 450     ULONG                           ulOS2_PriorityClass;
 451     ULONG                           ulOS2_SubPriority;
 452     ULONG                           ulrc;
 453
 454     m_nPriority = nPriority;
 455     if (m_nPriority <= 25)
 456         ulOS2_PriorityClass = PRTYC_IDLETIME;
 457     else if (m_nPriority <= 50)
 458         ulOS2_PriorityClass = PRTYC_REGULAR;
 459     else if (m_nPriority <= 75)
 460         ulOS2_PriorityClass = PRTYC_TIMECRITICAL;
 461     else if (m_nPriority <= 100)
 462         ulOS2_PriorityClass = PRTYC_FOREGROUNDSERVER;
 463     else
 464     {
 465         wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
 466         ulOS2_PriorityClass = PRTYC_REGULAR;
 467     }
 468     ulOS2_SubPriority = (ULONG) (((m_nPriority - 1) % 25 + 1) * 31.0 / 25);
 469     ulrc = ::DosSetPriority( PRTYS_THREAD
 470                             ,ulOS2_PriorityClass
 471                             ,ulOS2_SubPriority
 472                             ,(ULONG)m_hThread
 473                            );
 474     if (ulrc != 0)
 475     {
 476         wxLogSysError(_("Can't set thread priority"));
 477     }
 478 }
 479
 480 bool wxThreadInternal::Create( wxThread* pThread,
 481                                unsigned int uStackSize)
 482 {
 483     int tid;
 484
 485     if (!uStackSize)
 486         uStackSize = 131072;
 487
 488     pThread->m_critsect.Enter();
 489     tid = _beginthread(wxThreadInternal::OS2ThreadStart,
 490                              NULL, uStackSize, pThread);
 491     if(tid == -1)
 492     {
 493         wxLogSysError(_("Can't create thread"));
 494
 495         return false;
 496     }
 497     m_hThread = tid;
 498     if (m_nPriority != WXTHREAD_DEFAULT_PRIORITY)
 499     {
 500         SetPriority(m_nPriority);
 501     }
 502
 503     return true;
 504 }
 505
 506 bool wxThreadInternal::Suspend()
 507 {
 508     ULONG ulrc = ::DosSuspendThread(m_hThread);
 509
 510     if (ulrc != 0)
 511     {
 512         wxLogSysError(_("Can not suspend thread %lu"), m_hThread);
 513         return false;
 514     }
 515     m_eState = STATE_PAUSED;
 516
 517     return true;
 518 }
 519
 520 bool wxThreadInternal::Resume()
 521 {
 522     ULONG ulrc = ::DosResumeThread(m_hThread);
 523
 524     if (ulrc != 0)
 525     {
 526         wxLogSysError(_("Can not resume thread %lu"), m_hThread);
 527         return false;
 528     }
 529
 530     // don't change the state from STATE_EXITED because it's special and means
 531     // we are going to terminate without running any user code - if we did it,
 532     // the codei n Delete() wouldn't work
 533     if ( m_eState != STATE_EXITED )
 534     {
 535         m_eState = STATE_RUNNING;
 536     }
 537
 538     return true;
 539 }
 540
 541 // static functions
 542 // ----------------
 543
 544 wxThread *wxThread::This()
 545 {
 546     wxThread*                       pThread = m_pThread;
 547     return pThread;
 548 }
 549
 550 bool wxThread::IsMain()
 551 {
 552     PTIB ptib;
 553     PPIB ppib;
 554
 555     ::DosGetInfoBlocks(&ptib, &ppib);
 556
 557     if (ptib->tib_ptib2->tib2_ultid == s_ulIdMainThread)
 558         return true;
 559
 560     return false;
 561 }
 562
 563 #ifdef Yield
 564     #undef Yield
 565 #endif
 566
 567 void wxThread::Yield()
 568 {
 569     ::DosSleep(0);
 570 }
 571
 572 int wxThread::GetCPUCount()
 573 {
 574     ULONG CPUCount;
 575     APIRET ulrc;
 576     ulrc = ::DosQuerySysInfo(26, 26, (void *)&CPUCount, sizeof(ULONG));
 577     // QSV_NUMPROCESSORS(26) is typically not defined in header files
 578
 579     if (ulrc != 0)
 580         CPUCount = 1;
 581
 582     return CPUCount;
 583 }
 584
 585 unsigned long wxThread::GetCurrentId()
 586 {
 587     PTIB                            ptib;
 588     PPIB                            ppib;
 589
 590     ::DosGetInfoBlocks(&ptib, &ppib);
 591     return (unsigned long) ptib->tib_ptib2->tib2_ultid;
 592 }
 593
 594 bool wxThread::SetConcurrency(size_t level)
 595 {
 596     wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
 597
 598     // ok only for the default one
 599     if ( level == 0 )
 600         return 0;
 601
 602     // Don't know how to realize this on OS/2.
 603     return level == 1;
 604 }
 605
 606 // ctor and dtor
 607 // -------------
 608
 609 wxThread::wxThread(wxThreadKind kind)
 610 {
 611     m_internal = new wxThreadInternal();
 612
 613     m_isDetached = kind == wxTHREAD_DETACHED;
 614 }
 615
 616 wxThread::~wxThread()
 617 {
 618     delete m_internal;
 619 }
 620
 621 // create/start thread
 622 // -------------------
 623
 624 wxThreadError wxThread::Create(
 625   unsigned int                      uStackSize
 626 )
 627 {
 628     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect);
 629
 630     if ( !m_internal->Create(this, uStackSize) )
 631         return wxTHREAD_NO_RESOURCE;
 632
 633     return wxTHREAD_NO_ERROR;
 634 }
 635
 636 wxThreadError wxThread::Run()
 637 {
 638     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 639
 640     if ( m_internal->GetState() != STATE_NEW )
 641     {
 642         // actually, it may be almost any state at all, not only STATE_RUNNING
 643         return wxTHREAD_RUNNING;
 644     }
 645     return Resume();
 646 }
 647
 648 // suspend/resume thread
 649 // ---------------------
 650
 651 wxThreadError wxThread::Pause()
 652 {
 653     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 654
 655     return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 656 }
 657
 658 wxThreadError wxThread::Resume()
 659 {
 660     if (m_internal->GetState() == STATE_NEW)
 661     {
 662         m_internal->SetState(STATE_RUNNING);
 663         m_critsect.Leave();
 664         return wxTHREAD_NO_ERROR;
 665     }
 666
 667     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 668
 669     return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 670 }
 671
 672 // stopping thread
 673 // ---------------
 674
 675 wxThread::ExitCode wxThread::Wait()
 676 {
 677     // although under Windows we can wait for any thread, it's an error to
 678     // wait for a detached one in wxWin API
 679     wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
 680                  _T("can't wait for detached thread") );
 681     ExitCode rc = (ExitCode)-1;
 682     (void)Delete(&rc);
 683     return(rc);
 684 }
 685
 686 wxThreadError wxThread::Delete(ExitCode *pRc)
 687 {
 688     ExitCode rc = 0;
 689
 690     // Delete() is always safe to call, so consider all possible states
 691
 692     // we might need to resume the thread, but we might also not need to cancel
 693     // it if it doesn't run yet
 694     bool shouldResume = false,
 695          shouldCancel = true,
 696          isRunning = false;
 697
 698     // check if the thread already started to run
 699     {
 700         wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 701
 702         if ( m_internal->GetState() == STATE_NEW )
 703         {
 704             // WinThreadStart() will see it and terminate immediately, no need
 705             // to cancel the thread - but we still need to resume it to let it
 706             // run
 707             m_internal->SetState(STATE_EXITED);
 708
 709             Resume();   // it knows about STATE_EXITED special case
 710
 711             shouldCancel = false;
 712             isRunning = true;
 713
 714             // shouldResume is correctly set to false here
 715         }
 716         else
 717         {
 718             shouldResume = IsPaused();
 719         }
 720     }
 721
 722     // resume the thread if it is paused
 723     if ( shouldResume )
 724         Resume();
 725
 726     TID hThread = m_internal->GetHandle();
 727
 728     if ( isRunning || IsRunning())
 729     {
 730         if (IsMain())
 731         {
 732             // set flag for wxIsWaitingForThread()
 733             gs_bWaitingForThread = true;
 734         }
 735
 736         // ask the thread to terminate
 737         if ( shouldCancel )
 738         {
 739             wxCriticalSectionLocker lock(m_critsect);
 740
 741             m_internal->Cancel();
 742         }
 743
 744 #if 0
 745         // we can't just wait for the thread to terminate because it might be
 746         // calling some GUI functions and so it will never terminate before we
 747         // process the Windows messages that result from these functions
 748         DWORD result = 0;       // suppress warnings from broken compilers
 749         do
 750         {
 751             if ( IsMain() )
 752             {
 753                 // give the thread we're waiting for chance to do the GUI call
 754                 // it might be in
 755                 if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
 756                 {
 757                     wxMutexGuiLeave();
 758                 }
 759             }
 760
 761             result = ::DosWaitThread(&hThread, DCWW_NOWAIT);
 762             // FIXME: We ought to have a message processing loop here!!
 763
 764             switch ( result )
 765             {
 766                 case ERROR_INTERRUPT:
 767                 case ERROR_THREAD_NOT_TERMINATED:
 768                     break;
 769                 case ERROR_INVALID_THREADID:
 770                 case NO_ERROR:
 771                     // thread we're waiting for just terminated
 772                     // or even does not exist any more.
 773                     result = NO_ERROR;
 774                     break;
 775                 default:
 776                     wxFAIL_MSG(wxT("unexpected result of DosWaitThread"));
 777             }
 778             if ( IsMain() )
 779             {
 780                 // event processing - needed if we are the main thread
 781                 // to give other threads a chance to do remaining GUI
 782                 // processing and terminate cleanly.
 783                 wxTheApp->HandleSockets();
 784                 if (wxTheApp->Pending())
 785                   if ( !wxTheApp->DoMessage() )
 786                   {
 787                       // WM_QUIT received: kill the thread
 788                       Kill();
 789
 790                       return wxTHREAD_KILLED;
 791                   }
 792                   else
 793                     wxUsleep(10);
 794             }
 795             else
 796                 wxUsleep(10);
 797         } while ( result != NO_ERROR );
 798 #else // !wxUSE_GUI
 799         // simply wait for the thread to terminate
 800         //
 801         // OTOH, even console apps create windows (in wxExecute, for WinSock
 802         // &c), so may be use MsgWaitForMultipleObject() too here?
 803         if ( ::DosWaitThread(&hThread, DCWW_WAIT) != NO_ERROR )
 804         {
 805             wxFAIL_MSG(wxT("unexpected result of DosWaitThread"));
 806         }
 807 #endif // wxUSE_GUI/!wxUSE_GUI
 808
 809         if ( IsMain() )
 810         {
 811             gs_bWaitingForThread = false;
 812         }
 813     }
 814
 815 #if 0
 816     // although the thread might be already in the EXITED state it might not
 817     // have terminated yet and so we are not sure that it has actually
 818     // terminated if the "if" above hadn't been taken
 819     do
 820     {
 821         if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
 822         {
 823             wxLogLastError(wxT("GetExitCodeThread"));
 824
 825             rc = (ExitCode)-1;
 826         }
 827     } while ( (DWORD)rc == STILL_ACTIVE );
 828 #endif
 829
 830     if ( IsDetached() )
 831     {
 832         // if the thread exits normally, this is done in WinThreadStart, but in
 833         // this case it would have been too early because
 834         // MsgWaitForMultipleObject() would fail if the thread handle was
 835         // closed while we were waiting on it, so we must do it here
 836         delete this;
 837     }
 838
 839     if ( pRc )
 840         *pRc = rc;
 841
 842     return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
 843 }
 844
 845 wxThreadError wxThread::Kill()
 846 {
 847     if (!IsRunning())
 848         return wxTHREAD_NOT_RUNNING;
 849
 850     ::DosKillThread(m_internal->GetHandle());
 851     if (IsDetached())
 852     {
 853         delete this;
 854     }
 855     return wxTHREAD_NO_ERROR;
 856 }
 857
 858 void wxThread::Exit(ExitCode WXUNUSED(pStatus))
 859 {
 860     delete this;
 861     _endthread();
 862     wxFAIL_MSG(wxT("Couldn't return from DosExit()!"));
 863 }
 864
 865 void wxThread::SetPriority(
 866   unsigned int                      nPrio
 867 )
 868 {
 869     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 870
 871     m_internal->SetPriority(nPrio);
 872 }
 873
 874 unsigned int wxThread::GetPriority() const
 875 {
 876     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 877
 878     return m_internal->GetPriority();
 879 }
 880
 881 unsigned long wxThread::GetId() const
 882 {
 883     wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
 884
 885     return (unsigned long)m_internal->GetId();
 886 }
 887
 888 bool wxThread::IsRunning() const
 889 {
 890     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 891
 892     return(m_internal->GetState() == STATE_RUNNING);
 893 }
 894
 895 bool wxThread::IsAlive() const
 896 {
 897     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 898
 899     return (m_internal->GetState() == STATE_RUNNING) ||
 900            (m_internal->GetState() == STATE_PAUSED);
 901 }
 902
 903 bool wxThread::IsPaused() const
 904 {
 905     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 906
 907     return (m_internal->GetState() == STATE_PAUSED);
 908 }
 909
 910 bool wxThread::TestDestroy()
 911 {
 912     wxCriticalSectionLocker         lock((wxCriticalSection &)m_critsect);
 913
 914     return m_internal->GetState() == STATE_CANCELED;
 915 }
 916
 917 // ----------------------------------------------------------------------------
 918 // Automatic initialization for thread module
 919 // ----------------------------------------------------------------------------
 920
 921 class wxThreadModule : public wxModule
 922 {
 923 public:
 924     virtual bool OnInit();
 925     virtual void OnExit();
 926
 927 private:
 928     DECLARE_DYNAMIC_CLASS(wxThreadModule)
 929 };
 930
 931 IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
 932
 933 bool wxThreadModule::OnInit()
 934 {
 935     gs_pCritsectWaitingForGui = new wxCriticalSection();
 936
 937     gs_pCritsectGui = new wxCriticalSection();
 938     gs_pCritsectGui->Enter();
 939
 940     PTIB ptib;
 941     PPIB ppib;
 942
 943     ::DosGetInfoBlocks(&ptib, &ppib);
 944
 945     s_ulIdMainThread = ptib->tib_ptib2->tib2_ultid;
 946     return true;
 947 }
 948
 949 void wxThreadModule::OnExit()
 950 {
 951     if (gs_pCritsectGui)
 952     {
 953         gs_pCritsectGui->Leave();
 954 #if (!(defined(__VISAGECPP__) && (__IBMCPP__ < 400 || __IBMC__ < 400 )))
 955         delete gs_pCritsectGui;
 956 #endif
 957         gs_pCritsectGui = NULL;
 958     }
 959
 960 #if (!(defined(__VISAGECPP__) && (__IBMCPP__ < 400 || __IBMC__ < 400 )))
 961     wxDELETE(gs_pCritsectWaitingForGui);
 962 #endif
 963 }
 964
 965 // ----------------------------------------------------------------------------
 966 // Helper functions
 967 // ----------------------------------------------------------------------------
 968
 969 // wake up the main thread if it's in ::GetMessage()
 970 void WXDLLEXPORT wxWakeUpMainThread()
 971 {
 972 #if 0
 973     if ( !::WinPostQueueMsg(wxTheApp->m_hMq, WM_NULL, 0, 0) )
 974     {
 975         // should never happen
 976         wxLogLastError(wxT("WinPostMessage(WM_NULL)"));
 977     }
 978 #endif
 979 }
 980
 981 void wxMutexGuiEnterImpl()
 982 {
 983     // this would dead lock everything...
 984     wxASSERT_MSG( !wxThread::IsMain(),
 985                   wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
 986
 987     // the order in which we enter the critical sections here is crucial!!
 988
 989     // set the flag telling to the main thread that we want to do some GUI
 990     {
 991         wxCriticalSectionLocker enter(*gs_pCritsectWaitingForGui);
 992
 993         gs_nWaitingForGui++;
 994     }
 995
 996     wxWakeUpMainThread();
 997
 998     // now we may block here because the main thread will soon let us in
 999     // (during the next iteration of OnIdle())
1000     gs_pCritsectGui->Enter();
1001 }
1002
1003 void wxMutexGuiLeaveImpl()
1004 {
1005     wxCriticalSectionLocker enter(*gs_pCritsectWaitingForGui);
1006
1007     if ( wxThread::IsMain() )
1008     {
1009         gs_bGuiOwnedByMainThread = false;
1010     }
1011     else
1012     {
1013         // decrement the number of waiters now
1014         wxASSERT_MSG(gs_nWaitingForGui > 0,
1015                       wxT("calling wxMutexGuiLeave() without entering it first?") );
1016
1017         gs_nWaitingForGui--;
1018
1019         wxWakeUpMainThread();
1020     }
1021
1022     gs_pCritsectGui->Leave();
1023 }
1024
1025 void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
1026 {
1027     wxASSERT_MSG( wxThread::IsMain(),
1028                   wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
1029
1030     wxCriticalSectionLocker enter(*gs_pCritsectWaitingForGui);
1031
1032     if (gs_nWaitingForGui == 0)
1033     {
1034         // no threads are waiting for GUI - so we may acquire the lock without
1035         // any danger (but only if we don't already have it)
1036         if (!wxGuiOwnedByMainThread())
1037         {
1038             gs_pCritsectGui->Enter();
1039
1040             gs_bGuiOwnedByMainThread = true;
1041         }
1042         //else: already have it, nothing to do
1043     }
1044     else
1045     {
1046         // some threads are waiting, release the GUI lock if we have it
1047         if (wxGuiOwnedByMainThread())
1048         {
1049             wxMutexGuiLeave();
1050         }
1051         //else: some other worker thread is doing GUI
1052     }
1053 }
1054
1055 bool WXDLLEXPORT wxGuiOwnedByMainThread()
1056 {
1057     return gs_bGuiOwnedByMainThread;
1058 }
1059
1060 bool WXDLLEXPORT wxIsWaitingForThread()
1061 {
1062     return gs_bWaitingForThread;
1063 }
1064
1065 // ----------------------------------------------------------------------------
1066 // include common implementation code
1067 // ----------------------------------------------------------------------------
1068
1069 #include "wx/thrimpl.cpp"
1070
1071 #endif
1072   // wxUSE_THREADS