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Clean up string table before uninitializing DDEML
[wxWidgets.git] / src / msw / thread.cpp
diff --git a/src/msw/thread.cpp b/src/msw/thread.cpp
index d9582324560a0e6b14aa82d43c46a79a9729049e..d93d017704c2d27c7abe938b44eee16dd8d89bc1 100644 (file)
--- a/src/msw/thread.cpp
+++ b/src/msw/thread.cpp
@@ -1,11 +1,12 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////
-// Name:        thread.cpp
+// Name:        src/msw/thread.cpp
 // Purpose:     wxThread Implementation
 // Author:      Original from Wolfram Gloger/Guilhem Lavaux
 // Purpose:     wxThread Implementation
 // Author:      Original from Wolfram Gloger/Guilhem Lavaux
-// Modified by:
+// Modified by: Vadim Zeitlin to make it work :-)
 // Created:     04/22/98
 // RCS-ID:      $Id$
 // Created:     04/22/98
 // RCS-ID:      $Id$
-// Copyright:   (c) Wolfram Gloger (1996, 1997); Guilhem Lavaux (1998)
+// Copyright:   (c) Wolfram Gloger (1996, 1997), Guilhem Lavaux (1998);
+//                  Vadim Zeitlin (1999-2002)
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
@@ -25,429 +26,1152 @@
 #endif
 
 #ifndef WX_PRECOMP
 #endif
 
 #ifndef WX_PRECOMP
-    #include "wx/wx.h"
+#    include "wx/wx.h"
 #endif
 
 #if wxUSE_THREADS
 
 #endif
 
 #if wxUSE_THREADS
 
-#include <stdio.h>
-
-#include <windows.h>
+#include "wx/msw/private.h"
+#include "wx/msw/missing.h"
 
 #include "wx/module.h"
 #include "wx/thread.h"
 
 
 #include "wx/module.h"
 #include "wx/thread.h"
 
-enum thread_state
+// must have this symbol defined to get _beginthread/_endthread declarations
+#ifndef _MT
+    #define _MT
+#endif
+
+#if defined(__BORLANDC__)
+    #if !defined(__MT__)
+        // I can't set -tWM in the IDE (anyone?) so have to do this
+        #define __MT__
+    #endif
+
+    #if !defined(__MFC_COMPAT__)
+        // Needed to know about _beginthreadex etc..
+        #define __MFC_COMPAT__
+    #endif
+#endif // BC++
+
+// define wxUSE_BEGIN_THREAD if the compiler has _beginthreadex() function
+// which should be used instead of Win32 ::CreateThread() if possible
+#if defined(__VISUALC__) || \
+    (defined(__BORLANDC__) && (__BORLANDC__ >= 0x500)) || \
+    (defined(__GNUG__) && defined(__MSVCRT__)) || \
+    defined(__WATCOMC__) || defined(__MWERKS__)
+
+    #undef wxUSE_BEGIN_THREAD
+    #define wxUSE_BEGIN_THREAD
+#endif
+
+#ifdef wxUSE_BEGIN_THREAD
+    // this is where _beginthreadex() is declared
+    #include <process.h>
+
+    // the return type of the thread function entry point
+    typedef unsigned THREAD_RETVAL;
+
+    // the calling convention of the thread function entry point
+    #define THREAD_CALLCONV __stdcall
+#else
+    // the settings for CreateThread()
+    typedef DWORD THREAD_RETVAL;
+    #define THREAD_CALLCONV WINAPI
+#endif
+
+// ----------------------------------------------------------------------------
+// constants
+// ----------------------------------------------------------------------------
+
+// the possible states of the thread ("=>" shows all possible transitions from
+// this state)
+enum wxThreadState
 {
 {
-    STATE_IDLE = 0,
-    STATE_RUNNING,
-    STATE_CANCELED,
-    STATE_EXITED
+    STATE_NEW,          // didn't start execution yet (=> RUNNING)
+    STATE_RUNNING,      // thread is running (=> PAUSED, CANCELED)
+    STATE_PAUSED,       // thread is temporarily suspended (=> RUNNING)
+    STATE_CANCELED,     // thread should terminate a.s.a.p. (=> EXITED)
+    STATE_EXITED        // thread is terminating
 };
 
 // ----------------------------------------------------------------------------
 };
 
 // ----------------------------------------------------------------------------
-// static variables
+// this module globals
 // ----------------------------------------------------------------------------
 
 // ----------------------------------------------------------------------------
 
+// TLS index of the slot where we store the pointer to the current thread
+static DWORD gs_tlsThisThread = 0xFFFFFFFF;
+
 // id of the main thread - the one which can call GUI functions without first
 // calling wxMutexGuiEnter()
 // id of the main thread - the one which can call GUI functions without first
 // calling wxMutexGuiEnter()
-static HANDLE s_idMainThread;
+static DWORD gs_idMainThread = 0;
+
+// if it's FALSE, some secondary thread is holding the GUI lock
+static bool gs_bGuiOwnedByMainThread = TRUE;
 
 // critical section which controls access to all GUI functions: any secondary
 // thread (i.e. except the main one) must enter this crit section before doing
 // any GUI calls
 
 // critical section which controls access to all GUI functions: any secondary
 // thread (i.e. except the main one) must enter this crit section before doing
 // any GUI calls
-static wxCriticalSection *s_critsectGui;
+static wxCriticalSection *gs_critsectGui = NULL;
+
+// critical section which protects gs_nWaitingForGui variable
+static wxCriticalSection *gs_critsectWaitingForGui = NULL;
+
+// number of threads waiting for GUI in wxMutexGuiEnter()
+static size_t gs_nWaitingForGui = 0;
+
+// are we waiting for a thread termination?
+static bool gs_waitingForThread = FALSE;
 
 // ============================================================================
 
 // ============================================================================
-// Windows implementation of thread classes
+// Windows implementation of thread and related classes
 // ============================================================================
 
 // ----------------------------------------------------------------------------
 // ============================================================================
 
 // ----------------------------------------------------------------------------
-// wxMutex implementation
+// wxCriticalSection
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
+
+wxCriticalSection::wxCriticalSection()
+{
+    wxCOMPILE_TIME_ASSERT( sizeof(CRITICAL_SECTION) <= sizeof(wxCritSectBuffer),
+                           wxCriticalSectionBufferTooSmall );
+
+    ::InitializeCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+wxCriticalSection::~wxCriticalSection()
+{
+    ::DeleteCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+void wxCriticalSection::Enter()
+{
+    ::EnterCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+void wxCriticalSection::Leave()
+{
+    ::LeaveCriticalSection((CRITICAL_SECTION *)m_buffer);
+}
+
+// ----------------------------------------------------------------------------
+// wxMutex
+// ----------------------------------------------------------------------------
+
 class wxMutexInternal
 {
 public:
 class wxMutexInternal
 {
 public:
-    HANDLE p_mutex;
+    wxMutexInternal(wxMutexType mutexType);
+    ~wxMutexInternal();
+
+    bool IsOk() const { return m_mutex != NULL; }
+
+    wxMutexError Lock() { return LockTimeout(INFINITE); }
+    wxMutexError TryLock() { return LockTimeout(0); }
+    wxMutexError Unlock();
+
+private:
+    wxMutexError LockTimeout(DWORD milliseconds);
+
+    HANDLE m_mutex;
 };
 
 };
 
-wxMutex::wxMutex()
+// all mutexes are recursive under Win32 so we don't use mutexType
+wxMutexInternal::wxMutexInternal(wxMutexType WXUNUSED(mutexType))
 {
 {
-    p_internal = new wxMutexInternal;
-    p_internal->p_mutex = CreateMutex(NULL, FALSE, NULL);
-    if ( !p_internal->p_mutex )
+    // create a nameless (hence intra process and always private) mutex
+    m_mutex = ::CreateMutex
+                (
+                    NULL,       // default secutiry attributes
+                    FALSE,      // not initially locked
+                    NULL        // no name
+                );
+
+    if ( !m_mutex )
     {
     {
-        wxLogSysError(_("Can not create mutex."));
+        wxLogLastError(_T("CreateMutex()"));
     }
     }
-
-    m_locked = 0;
 }
 
 }
 
-wxMutex::~wxMutex()
+wxMutexInternal::~wxMutexInternal()
 {
 {
-    if (m_locked > 0)
-        wxLogDebug("Warning: freeing a locked mutex (%d locks).", m_locked);
-    CloseHandle(p_internal->p_mutex);
+    if ( m_mutex )
+    {
+        if ( !::CloseHandle(m_mutex) )
+        {
+            wxLogLastError(_T("CloseHandle(mutex)"));
+        }
+    }
 }
 
 }
 
-wxMutexError wxMutex::Lock()
+wxMutexError wxMutexInternal::LockTimeout(DWORD milliseconds)
 {
 {
-    DWORD ret;
-
-    ret = WaitForSingleObject(p_internal->p_mutex, INFINITE);
-    switch ( ret )
+    DWORD rc = ::WaitForSingleObject(m_mutex, milliseconds);
+    if ( rc == WAIT_ABANDONED )
     {
     {
-        case WAIT_ABANDONED:
-            return wxMUTEX_BUSY;
+        // the previous caller died without releasing the mutex, but now we can
+        // really lock it
+        wxLogDebug(_T("WaitForSingleObject() returned WAIT_ABANDONED"));
+
+        // use 0 timeout, normally we should always get it
+        rc = ::WaitForSingleObject(m_mutex, 0);
+    }
 
 
+    switch ( rc )
+    {
         case WAIT_OBJECT_0:
             // ok
             break;
 
         case WAIT_OBJECT_0:
             // ok
             break;
 
-        case WAIT_FAILED:
-            wxLogSysError(_("Couldn't acquire a mutex lock"));
-            return wxMUTEX_MISC_ERROR;
-
         case WAIT_TIMEOUT:
         case WAIT_TIMEOUT:
-        default:
-            wxFAIL_MSG("impossible return value in wxMutex::Lock");
-    }
-
-    m_locked++;
-    return wxMUTEX_NO_ERROR;
-}
+            return wxMUTEX_BUSY;
 
 
-wxMutexError wxMutex::TryLock()
-{
-    DWORD ret;
+        case WAIT_ABANDONED:        // checked for above
+        default:
+            wxFAIL_MSG(wxT("impossible return value in wxMutex::Lock"));
+            // fall through
 
 
-    ret = WaitForSingleObject(p_internal->p_mutex, 0);
-    if (ret == WAIT_TIMEOUT || ret == WAIT_ABANDONED)
-        return wxMUTEX_BUSY;
+        case WAIT_FAILED:
+            wxLogLastError(_T("WaitForSingleObject(mutex)"));
+            return wxMUTEX_MISC_ERROR;
+    }
 
 
-    m_locked++;
     return wxMUTEX_NO_ERROR;
 }
 
     return wxMUTEX_NO_ERROR;
 }
 
-wxMutexError wxMutex::Unlock()
+wxMutexError wxMutexInternal::Unlock()
 {
 {
-    if (m_locked > 0)
-        m_locked--;
-
-    BOOL ret = ReleaseMutex(p_internal->p_mutex);
-    if ( ret == 0 )
+    if ( !::ReleaseMutex(m_mutex) )
     {
     {
-        wxLogSysError(_("Couldn't release a mutex"));
+        wxLogLastError(_("ReleaseMutex()"));
+
         return wxMUTEX_MISC_ERROR;
     }
 
     return wxMUTEX_NO_ERROR;
 }
 
         return wxMUTEX_MISC_ERROR;
     }
 
     return wxMUTEX_NO_ERROR;
 }
 
-// ----------------------------------------------------------------------------
-// wxCondition implementation
-// ----------------------------------------------------------------------------
+// --------------------------------------------------------------------------
+// wxSemaphore
+// --------------------------------------------------------------------------
 
 
-class wxConditionInternal
+// a trivial wrapper around Win32 semaphore
+class wxSemaphoreInternal
 {
 public:
 {
 public:
-    HANDLE event;
-    int waiters;
+    wxSemaphoreInternal(int initialcount, int maxcount);
+    ~wxSemaphoreInternal();
+
+    bool IsOk() const { return m_semaphore != NULL; }
+
+    wxSemaError Wait() { return WaitTimeout(INFINITE); }
+    wxSemaError TryWait() { return WaitTimeout(0); }
+    wxSemaError WaitTimeout(unsigned long milliseconds);
+
+    wxSemaError Post();
+
+private:
+    HANDLE m_semaphore;
 };
 
 };
 
-wxCondition::wxCondition()
+wxSemaphoreInternal::wxSemaphoreInternal(int initialcount, int maxcount)
 {
 {
-    p_internal = new wxConditionInternal;
-    p_internal->event = CreateEvent(NULL, FALSE, FALSE, NULL);
-    if ( !p_internal->event )
+    if ( maxcount == 0 )
     {
     {
-        wxLogSysError(_("Can not create event object."));
+        // make it practically infinite
+        maxcount = INT_MAX;
     }
 
     }
 
-    p_internal->waiters = 0;
-}
+    m_semaphore = ::CreateSemaphore
+                    (
+                        NULL,           // default security attributes
+                        initialcount,
+                        maxcount,
+                        NULL            // no name
+                    );
 
 
-wxCondition::~wxCondition()
-{
-    CloseHandle(p_internal->event);
+    if ( !m_semaphore )
+    {
+        wxLogLastError(_T("CreateSemaphore()"));
+    }
 }
 
 }
 
-void wxCondition::Wait(wxMutex& mutex)
+wxSemaphoreInternal::~wxSemaphoreInternal()
 {
 {
-    mutex.Unlock();
-    p_internal->waiters++;
-    WaitForSingleObject(p_internal->event, INFINITE);
-    p_internal->waiters--;
-    mutex.Lock();
+    if ( m_semaphore )
+    {
+        if ( !::CloseHandle(m_semaphore) )
+        {
+            wxLogLastError(_T("CloseHandle(semaphore)"));
+        }
+    }
 }
 
 }
 
-bool wxCondition::Wait(wxMutex& mutex,
-                       unsigned long sec,
-                       unsigned long nsec)
+wxSemaError wxSemaphoreInternal::WaitTimeout(unsigned long milliseconds)
 {
 {
-    DWORD ret;
+    DWORD rc = ::WaitForSingleObject( m_semaphore, milliseconds );
 
 
-    mutex.Unlock();
-    p_internal->waiters++;
-    ret = WaitForSingleObject(p_internal->event, (sec*1000)+(nsec/1000000));
-    p_internal->waiters--;
-    mutex.Lock();
+    switch ( rc )
+    {
+        case WAIT_OBJECT_0:
+           return wxSEMA_NO_ERROR;
 
 
-    return (ret != WAIT_TIMEOUT);
-}
+        case WAIT_TIMEOUT:
+           return wxSEMA_BUSY;
 
 
-void wxCondition::Signal()
-{
-    SetEvent(p_internal->event);
+        default:
+            wxLogLastError(_T("WaitForSingleObject(semaphore)"));
+    }
+
+    return wxSEMA_MISC_ERROR;
 }
 
 }
 
-void wxCondition::Broadcast()
+wxSemaError wxSemaphoreInternal::Post()
 {
 {
-    int i;
-
-    for (i=0;i<p_internal->waiters;i++)
+    if ( !::ReleaseSemaphore(m_semaphore, 1, NULL /* ptr to previous count */) )
     {
     {
-        if ( SetEvent(p_internal->event) == 0 )
-        {
-            wxLogSysError(_("Couldn't change the state of event object."));
-        }
+        wxLogLastError(_T("ReleaseSemaphore"));
+
+        return wxSEMA_MISC_ERROR;
     }
     }
+
+    return wxSEMA_NO_ERROR;
 }
 
 }
 
-// ----------------------------------------------------------------------------
-// wxCriticalSection implementation
-// ----------------------------------------------------------------------------
+// --------------------------------------------------------------------------
+// wxCondition
+// --------------------------------------------------------------------------
 
 
-class wxCriticalSectionInternal
+// Win32 doesn't have explicit support for the POSIX condition variables and
+// the Win32 events have quite different semantics, so we reimplement the
+// conditions from scratch using the mutexes and semaphores
+class wxConditionInternal
 {
 public:
 {
 public:
-    // init the critical section object
-    wxCriticalSectionInternal()
-        { ::InitializeCriticalSection(&m_data); }
+    wxConditionInternal(wxMutex& mutex);
 
 
-    // implicit cast to the associated data
-    operator CRITICAL_SECTION *() { return &m_data; }
+    bool IsOk() const { return m_mutex.IsOk() && m_semaphore.IsOk(); }
 
 
-    // free the associated ressources
-    ~wxCriticalSectionInternal()
-        { ::DeleteCriticalSection(&m_data); }
+    wxCondError Wait();
+    wxCondError WaitTimeout(unsigned long milliseconds);
+
+    wxCondError Signal();
+    wxCondError Broadcast();
 
 private:
 
 private:
-    CRITICAL_SECTION m_data;
+    // the number of threads currently waiting for this condition
+    LONG m_numWaiters;
+
+    // the critical section protecting m_numWaiters
+    wxCriticalSection m_csWaiters;
+
+    wxMutex& m_mutex;
+    wxSemaphore m_semaphore;
 };
 
 };
 
-wxCriticalSection::wxCriticalSection()
+wxConditionInternal::wxConditionInternal(wxMutex& mutex)
+                   : m_mutex(mutex)
 {
 {
-    m_critsect = new wxCriticalSectionInternal;
+    // another thread can't access it until we return from ctor, so no need to
+    // protect access to m_numWaiters here
+    m_numWaiters = 0;
 }
 
 }
 
-wxCriticalSection::~wxCriticalSection()
+wxCondError wxConditionInternal::Wait()
 {
 {
-    delete m_critsect;
+    // increment the number of waiters
+    ::InterlockedIncrement(&m_numWaiters);
+
+    m_mutex.Unlock();
+
+    // a potential race condition can occur here
+    //
+    // after a thread increments nwaiters, and unlocks the mutex and before the
+    // semaphore.Wait() is called, if another thread can cause a signal to be
+    // generated
+    //
+    // this race condition is handled by using a semaphore and incrementing the
+    // semaphore only if 'nwaiters' is greater that zero since the semaphore,
+    // can 'remember' signals the race condition will not occur
+
+    // wait ( if necessary ) and decrement semaphore
+    wxSemaError err = m_semaphore.Wait();
+    m_mutex.Lock();
+
+    return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
 }
 
 }
 
-void wxCriticalSection::Enter()
+wxCondError wxConditionInternal::WaitTimeout(unsigned long milliseconds)
+{
+    ::InterlockedIncrement(&m_numWaiters);
+
+    m_mutex.Unlock();
+
+    // a race condition can occur at this point in the code
+    //
+    // please see the comments in Wait(), for details
+
+    wxSemaError err = m_semaphore.WaitTimeout(milliseconds);
+
+    if ( err == wxSEMA_BUSY )
+    {
+        // another potential race condition exists here it is caused when a
+        // 'waiting' thread timesout, and returns from WaitForSingleObject, but
+        // has not yet decremented 'nwaiters'.
+        //
+        // at this point if another thread calls signal() then the semaphore
+        // will be incremented, but the waiting thread will miss it.
+        //
+        // to handle this particular case, the waiting thread calls
+        // WaitForSingleObject again with a timeout of 0, after locking
+        // 'nwaiters_mutex'. this call does not block because of the zero
+        // timeout, but will allow the waiting thread to catch the missed
+        // signals.
+        wxCriticalSectionLocker lock(m_csWaiters);
+
+        err = m_semaphore.WaitTimeout(0);
+
+        if ( err != wxSEMA_NO_ERROR )
+        {
+            m_numWaiters--;
+        }
+    }
+
+    m_mutex.Lock();
+
+    return err == wxSEMA_NO_ERROR ? wxCOND_NO_ERROR : wxCOND_MISC_ERROR;
+}
+
+wxCondError wxConditionInternal::Signal()
 {
 {
-    ::EnterCriticalSection(*m_critsect);
+    wxCriticalSectionLocker lock(m_csWaiters);
+
+    if ( m_numWaiters > 0 )
+    {
+        // increment the semaphore by 1
+        if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
+            return wxCOND_MISC_ERROR;
+
+        m_numWaiters--;
+    }
+
+    return wxCOND_NO_ERROR;
 }
 
 }
 
-void wxCriticalSection::Leave()
+wxCondError wxConditionInternal::Broadcast()
 {
 {
-    ::LeaveCriticalSection(*m_critsect);
+    wxCriticalSectionLocker lock(m_csWaiters);
+
+    while ( m_numWaiters > 0 )
+    {
+        if ( m_semaphore.Post() != wxSEMA_NO_ERROR )
+            return wxCOND_MISC_ERROR;
+
+        m_numWaiters--;
+    }
+
+    return wxCOND_NO_ERROR;
 }
 
 // ----------------------------------------------------------------------------
 // wxThread implementation
 // ----------------------------------------------------------------------------
 
 }
 
 // ----------------------------------------------------------------------------
 // wxThread implementation
 // ----------------------------------------------------------------------------
 
+// wxThreadInternal class
+// ----------------------
+
 class wxThreadInternal
 {
 public:
 class wxThreadInternal
 {
 public:
-    static DWORD WinThreadStart(LPVOID arg);
+    wxThreadInternal()
+    {
+        m_hThread = 0;
+        m_state = STATE_NEW;
+        m_priority = WXTHREAD_DEFAULT_PRIORITY;
+    }
+
+    ~wxThreadInternal()
+    {
+        Free();
+    }
+
+    void Free()
+    {
+        if ( m_hThread )
+        {
+            if ( !::CloseHandle(m_hThread) )
+            {
+                wxLogLastError(wxT("CloseHandle(thread)"));
+            }
+
+            m_hThread = 0;
+        }
+    }
 
 
-    HANDLE thread_id;
-    int state;
-    int prio, defer;
-    DWORD tid;
+    // create a new (suspended) thread (for the given thread object)
+    bool Create(wxThread *thread, unsigned int stackSize);
+
+    // suspend/resume/terminate
+    bool Suspend();
+    bool Resume();
+    void Cancel() { m_state = STATE_CANCELED; }
+
+    // thread state
+    void SetState(wxThreadState state) { m_state = state; }
+    wxThreadState GetState() const { return m_state; }
+
+    // thread priority
+    void SetPriority(unsigned int priority);
+    unsigned int GetPriority() const { return m_priority; }
+
+    // thread handle and id
+    HANDLE GetHandle() const { return m_hThread; }
+    DWORD  GetId() const { return m_tid; }
+
+    // thread function
+    static THREAD_RETVAL THREAD_CALLCONV WinThreadStart(void *thread);
+
+private:
+    HANDLE        m_hThread;    // handle of the thread
+    wxThreadState m_state;      // state, see wxThreadState enum
+    unsigned int  m_priority;   // thread priority in "wx" units
+    DWORD         m_tid;        // thread id
 };
 
 };
 
-DWORD wxThreadInternal::WinThreadStart(LPVOID arg)
+THREAD_RETVAL THREAD_CALLCONV wxThreadInternal::WinThreadStart(void *param)
 {
 {
-    wxThread *ptr = (wxThread *)arg;
-    DWORD ret;
+    THREAD_RETVAL rc;
+    bool wasCancelled;
+
+    // first of all, check whether we hadn't been cancelled already and don't
+    // start the user code at all then
+    wxThread *thread = (wxThread *)param;
+    if ( thread->m_internal->GetState() == STATE_EXITED )
+    {
+        rc = (THREAD_RETVAL)-1;
+        wasCancelled = TRUE;
+    }
+    else // do run thread
+    {
+        // store the thread object in the TLS
+        if ( !::TlsSetValue(gs_tlsThisThread, thread) )
+        {
+            wxLogSysError(_("Can not start thread: error writing TLS."));
+
+            return (DWORD)-1;
+        }
+
+        rc = (THREAD_RETVAL)thread->Entry();
+
+        // enter m_critsect before changing the thread state
+        thread->m_critsect.Enter();
+        wasCancelled = thread->m_internal->GetState() == STATE_CANCELED;
+        thread->m_internal->SetState(STATE_EXITED);
+        thread->m_critsect.Leave();
+    }
 
 
-    ret = (DWORD)ptr->Entry();
-    ptr->p_internal->state = STATE_EXITED;
+    thread->OnExit();
+
+    // if the thread was cancelled (from Delete()), then its handle is still
+    // needed there
+    if ( thread->IsDetached() && !wasCancelled )
+    {
+        // auto delete
+        delete thread;
+    }
+    //else: the joinable threads handle will be closed when Wait() is done
 
 
-    return ret;
+    return rc;
 }
 
 }
 
-wxThreadError wxThread::Create()
+void wxThreadInternal::SetPriority(unsigned int priority)
 {
 {
-    int prio = p_internal->prio;
+    m_priority = priority;
+
+    // translate wxWindows priority to the Windows one
+    int win_priority;
+    if (m_priority <= 20)
+        win_priority = THREAD_PRIORITY_LOWEST;
+    else if (m_priority <= 40)
+        win_priority = THREAD_PRIORITY_BELOW_NORMAL;
+    else if (m_priority <= 60)
+        win_priority = THREAD_PRIORITY_NORMAL;
+    else if (m_priority <= 80)
+        win_priority = THREAD_PRIORITY_ABOVE_NORMAL;
+    else if (m_priority <= 100)
+        win_priority = THREAD_PRIORITY_HIGHEST;
+    else
+    {
+        wxFAIL_MSG(wxT("invalid value of thread priority parameter"));
+        win_priority = THREAD_PRIORITY_NORMAL;
+    }
 
 
-    p_internal->thread_id = CreateThread(NULL, 0,
-            (LPTHREAD_START_ROUTINE)wxThreadInternal::WinThreadStart,
-            (void *)this, CREATE_SUSPENDED, &p_internal->tid);
+    if ( !::SetThreadPriority(m_hThread, win_priority) )
+    {
+        wxLogSysError(_("Can't set thread priority"));
+    }
+}
 
 
-    if ( p_internal->thread_id == NULL )
+bool wxThreadInternal::Create(wxThread *thread, unsigned int stackSize)
+{
+    // for compilers which have it, we should use C RTL function for thread
+    // creation instead of Win32 API one because otherwise we will have memory
+    // leaks if the thread uses C RTL (and most threads do)
+#ifdef wxUSE_BEGIN_THREAD
+
+    // Watcom is reported to not like 0 stack size (which means "use default"
+    // for the other compilers and is also the default value for stackSize)
+#ifdef __WATCOMC__
+    if ( !stackSize )
+        stackSize = 10240;
+#endif // __WATCOMC__
+
+    m_hThread = (HANDLE)_beginthreadex
+                        (
+                          NULL,                             // default security
+                          stackSize,
+                          wxThreadInternal::WinThreadStart, // entry point
+                          thread,
+                          CREATE_SUSPENDED,
+                          (unsigned int *)&m_tid
+                        );
+#else // compiler doesn't have _beginthreadex
+    m_hThread = ::CreateThread
+                  (
+                    NULL,                               // default security
+                    stackSize,                          // stack size
+                    wxThreadInternal::WinThreadStart,   // thread entry point
+                    (LPVOID)thread,                     // parameter
+                    CREATE_SUSPENDED,                   // flags
+                    &m_tid                              // [out] thread id
+                  );
+#endif // _beginthreadex/CreateThread
+
+    if ( m_hThread == NULL )
     {
         wxLogSysError(_("Can't create thread"));
     {
         wxLogSysError(_("Can't create thread"));
-        return wxTHREAD_NO_RESOURCE;
+
+        return FALSE;
     }
 
     }
 
-    int win_prio;
-    if (prio <= 20)
-        win_prio = THREAD_PRIORITY_LOWEST;
-    else if (prio <= 40)
-        win_prio = THREAD_PRIORITY_BELOW_NORMAL;
-    else if (prio <= 60)
-        win_prio = THREAD_PRIORITY_NORMAL;
-    else if (prio <= 80)
-        win_prio = THREAD_PRIORITY_ABOVE_NORMAL;
-    else if (prio <= 100)
-        win_prio = THREAD_PRIORITY_HIGHEST;
-    else
+    if ( m_priority != WXTHREAD_DEFAULT_PRIORITY )
     {
     {
-        wxFAIL_MSG("invalid value of thread priority parameter");
-        win_prio = THREAD_PRIORITY_NORMAL;
+        SetPriority(m_priority);
     }
 
     }
 
-    SetThreadPriority(p_internal->thread_id, win_prio);
+    return TRUE;
+}
 
 
-    ResumeThread(p_internal->thread_id);
-    p_internal->state = STATE_RUNNING;
+bool wxThreadInternal::Suspend()
+{
+    DWORD nSuspendCount = ::SuspendThread(m_hThread);
+    if ( nSuspendCount == (DWORD)-1 )
+    {
+        wxLogSysError(_("Can not suspend thread %x"), m_hThread);
 
 
-    return wxTHREAD_NO_ERROR;
+        return FALSE;
+    }
+
+    m_state = STATE_PAUSED;
+
+    return TRUE;
 }
 
 }
 
-wxThreadError wxThread::Destroy()
+bool wxThreadInternal::Resume()
 {
 {
-    if (p_internal->state != STATE_RUNNING)
-        return wxTHREAD_NOT_RUNNING;
+    DWORD nSuspendCount = ::ResumeThread(m_hThread);
+    if ( nSuspendCount == (DWORD)-1 )
+    {
+        wxLogSysError(_("Can not resume thread %x"), m_hThread);
 
 
-    if ( p_internal->defer )
-        // soft termination: just set the flag and wait until the thread
-        // auto terminates
-        p_internal->state = STATE_CANCELED;
-    else
-        // kill the thread
-        TerminateThread(p_internal->thread_id, 0);
+        return FALSE;
+    }
 
 
-    return wxTHREAD_NO_ERROR;
+    // don't change the state from STATE_EXITED because it's special and means
+    // we are going to terminate without running any user code - if we did it,
+    // the codei n Delete() wouldn't work
+    if ( m_state != STATE_EXITED )
+    {
+        m_state = STATE_RUNNING;
+    }
+
+    return TRUE;
 }
 
 }
 
-wxThreadError wxThread::Pause()
+// static functions
+// ----------------
+
+wxThread *wxThread::This()
 {
 {
-    DWORD nSuspendCount = ::SuspendThread(p_internal->thread_id);
-    if ( nSuspendCount == (DWORD)-1 )
+    wxThread *thread = (wxThread *)::TlsGetValue(gs_tlsThisThread);
+
+    // be careful, 0 may be a valid return value as well
+    if ( !thread && (::GetLastError() != NO_ERROR) )
     {
     {
-        wxLogSysError(_("Can not suspend thread %x"), p_internal->thread_id);
+        wxLogSysError(_("Couldn't get the current thread pointer"));
 
 
-        return wxTHREAD_MISC_ERROR;   // no idea what might provoke this error...
+        // return NULL...
     }
 
     }
 
-    return wxTHREAD_NO_ERROR;
+    return thread;
 }
 
 }
 
-wxThreadError wxThread::Resume()
+bool wxThread::IsMain()
 {
 {
-    DWORD nSuspendCount = ::ResumeThread(p_internal->thread_id);
-    if ( nSuspendCount == (DWORD)-1 )
+    return ::GetCurrentThreadId() == gs_idMainThread;
+}
+
+#ifdef Yield
+#undef Yield
+#endif
+
+void wxThread::Yield()
+{
+    // 0 argument to Sleep() is special and means to just give away the rest of
+    // our timeslice
+    ::Sleep(0);
+}
+
+void wxThread::Sleep(unsigned long milliseconds)
+{
+    ::Sleep(milliseconds);
+}
+
+int wxThread::GetCPUCount()
+{
+    SYSTEM_INFO si;
+    GetSystemInfo(&si);
+
+    return si.dwNumberOfProcessors;
+}
+
+unsigned long wxThread::GetCurrentId()
+{
+    return (unsigned long)::GetCurrentThreadId();
+}
+
+bool wxThread::SetConcurrency(size_t level)
+{
+    wxASSERT_MSG( IsMain(), _T("should only be called from the main thread") );
+
+    // ok only for the default one
+    if ( level == 0 )
+        return 0;
+
+    // get system affinity mask first
+    HANDLE hProcess = ::GetCurrentProcess();
+    DWORD dwProcMask, dwSysMask;
+    if ( ::GetProcessAffinityMask(hProcess, &dwProcMask, &dwSysMask) == 0 )
+    {
+        wxLogLastError(_T("GetProcessAffinityMask"));
+
+        return FALSE;
+    }
+
+    // how many CPUs have we got?
+    if ( dwSysMask == 1 )
+    {
+        // don't bother with all this complicated stuff - on a single
+        // processor system it doesn't make much sense anyhow
+        return level == 1;
+    }
+
+    // calculate the process mask: it's a bit vector with one bit per
+    // processor; we want to schedule the process to run on first level
+    // CPUs
+    DWORD bit = 1;
+    while ( bit )
+    {
+        if ( dwSysMask & bit )
+        {
+            // ok, we can set this bit
+            dwProcMask |= bit;
+
+            // another process added
+            if ( !--level )
+            {
+                // and that's enough
+                break;
+            }
+        }
+
+        // next bit
+        bit <<= 1;
+    }
+
+    // could we set all bits?
+    if ( level != 0 )
     {
     {
-        wxLogSysError(_("Can not resume thread %x"), p_internal->thread_id);
+        wxLogDebug(_T("bad level %u in wxThread::SetConcurrency()"), level);
 
 
-        return wxTHREAD_MISC_ERROR;   // no idea what might provoke this error...
+        return FALSE;
     }
 
     }
 
+    // set it: we can't link to SetProcessAffinityMask() because it doesn't
+    // exist in Win9x, use RT binding instead
+
+    typedef BOOL (*SETPROCESSAFFINITYMASK)(HANDLE, DWORD);
+
+    // can use static var because we're always in the main thread here
+    static SETPROCESSAFFINITYMASK pfnSetProcessAffinityMask = NULL;
+
+    if ( !pfnSetProcessAffinityMask )
+    {
+        HMODULE hModKernel = ::LoadLibrary(_T("kernel32"));
+        if ( hModKernel )
+        {
+            pfnSetProcessAffinityMask = (SETPROCESSAFFINITYMASK)
+                ::GetProcAddress(hModKernel, "SetProcessAffinityMask");
+        }
+
+        // we've discovered a MT version of Win9x!
+        wxASSERT_MSG( pfnSetProcessAffinityMask,
+                      _T("this system has several CPUs but no SetProcessAffinityMask function?") );
+    }
+
+    if ( !pfnSetProcessAffinityMask )
+    {
+        // msg given above - do it only once
+        return FALSE;
+    }
+
+    if ( pfnSetProcessAffinityMask(hProcess, dwProcMask) == 0 )
+    {
+        wxLogLastError(_T("SetProcessAffinityMask"));
+
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+// ctor and dtor
+// -------------
+
+wxThread::wxThread(wxThreadKind kind)
+{
+    m_internal = new wxThreadInternal();
+
+    m_isDetached = kind == wxTHREAD_DETACHED;
+}
+
+wxThread::~wxThread()
+{
+    delete m_internal;
+}
+
+// create/start thread
+// -------------------
+
+wxThreadError wxThread::Create(unsigned int stackSize)
+{
+    wxCriticalSectionLocker lock(m_critsect);
+
+    if ( !m_internal->Create(this, stackSize) )
+        return wxTHREAD_NO_RESOURCE;
+
     return wxTHREAD_NO_ERROR;
 }
 
     return wxTHREAD_NO_ERROR;
 }
 
-void wxThread::Exit(void *status)
+wxThreadError wxThread::Run()
 {
 {
-    p_internal->state = STATE_EXITED;
-    ExitThread((DWORD)status);
+    wxCriticalSectionLocker lock(m_critsect);
+
+    if ( m_internal->GetState() != STATE_NEW )
+    {
+        // actually, it may be almost any state at all, not only STATE_RUNNING
+        return wxTHREAD_RUNNING;
+    }
+
+    // the thread has just been created and is still suspended - let it run
+    return Resume();
 }
 
 }
 
-void wxThread::SetPriority(int prio)
+// suspend/resume thread
+// ---------------------
+
+wxThreadError wxThread::Pause()
 {
 {
-    p_internal->prio = prio;
+    wxCriticalSectionLocker lock(m_critsect);
+
+    return m_internal->Suspend() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 }
 
 }
 
-int wxThread::GetPriority() const
+wxThreadError wxThread::Resume()
 {
 {
-    return p_internal->prio;
+    wxCriticalSectionLocker lock(m_critsect);
+
+    return m_internal->Resume() ? wxTHREAD_NO_ERROR : wxTHREAD_MISC_ERROR;
 }
 
 }
 
-void wxThread::DeferDestroy(bool on)
+// stopping thread
+// ---------------
+
+wxThread::ExitCode wxThread::Wait()
 {
 {
-    p_internal->defer = on;
+    // although under Windows we can wait for any thread, it's an error to
+    // wait for a detached one in wxWin API
+    wxCHECK_MSG( !IsDetached(), (ExitCode)-1,
+                 _T("can't wait for detached thread") );
+
+    ExitCode rc = (ExitCode)-1;
+
+    (void)Delete(&rc);
+
+    m_internal->Free();
+
+    return rc;
 }
 
 }
 
-bool wxThread::TestDestroy()
+wxThreadError wxThread::Delete(ExitCode *pRc)
 {
 {
-    return p_internal->state == STATE_CANCELED;
+    ExitCode rc = 0;
+
+    // Delete() is always safe to call, so consider all possible states
+
+    // we might need to resume the thread, but we might also not need to cancel
+    // it if it doesn't run yet
+    bool shouldResume = FALSE,
+         shouldCancel = TRUE,
+         isRunning = FALSE;
+
+    // check if the thread already started to run
+    {
+        wxCriticalSectionLocker lock(m_critsect);
+
+        if ( m_internal->GetState() == STATE_NEW )
+        {
+            // WinThreadStart() will see it and terminate immediately, no need
+            // to cancel the thread - but we still need to resume it to let it
+            // run
+            m_internal->SetState(STATE_EXITED);
+
+            Resume();   // it knows about STATE_EXITED special case
+
+            shouldCancel = FALSE;
+            isRunning = TRUE;
+
+            // shouldResume is correctly set to FALSE here
+        }
+        else
+        {
+            shouldResume = IsPaused();
+        }
+    }
+
+    // resume the thread if it is paused
+    if ( shouldResume )
+        Resume();
+
+    HANDLE hThread = m_internal->GetHandle();
+
+    // does is still run?
+    if ( isRunning || IsRunning() )
+    {
+        if ( IsMain() )
+        {
+            // set flag for wxIsWaitingForThread()
+            gs_waitingForThread = TRUE;
+        }
+
+        // ask the thread to terminate
+        if ( shouldCancel )
+        {
+            wxCriticalSectionLocker lock(m_critsect);
+
+            m_internal->Cancel();
+        }
+
+#if wxUSE_GUI
+        // we can't just wait for the thread to terminate because it might be
+        // calling some GUI functions and so it will never terminate before we
+        // process the Windows messages that result from these functions
+        DWORD result = 0;       // suppress warnings from broken compilers
+        do
+        {
+            if ( IsMain() )
+            {
+                // give the thread we're waiting for chance to do the GUI call
+                // it might be in
+                if ( (gs_nWaitingForGui > 0) && wxGuiOwnedByMainThread() )
+                {
+                    wxMutexGuiLeave();
+                }
+            }
+
+            result = ::MsgWaitForMultipleObjects
+                     (
+                       1,              // number of objects to wait for
+                       &hThread,       // the objects
+                       FALSE,          // don't wait for all objects
+                       INFINITE,       // no timeout
+                       QS_ALLINPUT |   // return as soon as there are any events
+                       QS_ALLPOSTMESSAGE
+                     );
+
+            switch ( result )
+            {
+                case 0xFFFFFFFF:
+                    // error
+                    wxLogSysError(_("Can not wait for thread termination"));
+                    Kill();
+                    return wxTHREAD_KILLED;
+
+                case WAIT_OBJECT_0:
+                    // thread we're waiting for terminated
+                    break;
+
+                case WAIT_OBJECT_0 + 1:
+                    // new message arrived, process it
+                    if ( !wxTheApp->DoMessage() )
+                    {
+                        // WM_QUIT received: kill the thread
+                        Kill();
+
+                        return wxTHREAD_KILLED;
+                    }
+                    break;
+
+                default:
+                    wxFAIL_MSG(wxT("unexpected result of MsgWaitForMultipleObject"));
+            }
+        } while ( result != WAIT_OBJECT_0 );
+#else // !wxUSE_GUI
+        // simply wait for the thread to terminate
+        //
+        // OTOH, even console apps create windows (in wxExecute, for WinSock
+        // &c), so may be use MsgWaitForMultipleObject() too here?
+        if ( WaitForSingleObject(hThread, INFINITE) != WAIT_OBJECT_0 )
+        {
+            wxFAIL_MSG(wxT("unexpected result of WaitForSingleObject"));
+        }
+#endif // wxUSE_GUI/!wxUSE_GUI
+
+        if ( IsMain() )
+        {
+            gs_waitingForThread = FALSE;
+        }
+    }
+
+    // although the thread might be already in the EXITED state it might not
+    // have terminated yet and so we are not sure that it has actually
+    // terminated if the "if" above hadn't been taken
+    do
+    {
+        if ( !::GetExitCodeThread(hThread, (LPDWORD)&rc) )
+        {
+            wxLogLastError(wxT("GetExitCodeThread"));
+
+            rc = (ExitCode)-1;
+        }
+    } while ( (DWORD)rc == STILL_ACTIVE );
+
+    if ( IsDetached() )
+    {
+        // if the thread exits normally, this is done in WinThreadStart, but in
+        // this case it would have been too early because
+        // MsgWaitForMultipleObject() would fail if the thread handle was
+        // closed while we were waiting on it, so we must do it here
+        delete this;
+    }
+
+    if ( pRc )
+        *pRc = rc;
+
+    return rc == (ExitCode)-1 ? wxTHREAD_MISC_ERROR : wxTHREAD_NO_ERROR;
 }
 
 }
 
-void *wxThread::Join()
+wxThreadError wxThread::Kill()
 {
 {
-    DWORD exit_code;
+    if ( !IsRunning() )
+        return wxTHREAD_NOT_RUNNING;
 
 
-    if (p_internal->state == STATE_IDLE)
-        return NULL;
+    if ( !::TerminateThread(m_internal->GetHandle(), (DWORD)-1) )
+    {
+        wxLogSysError(_("Couldn't terminate thread"));
 
 
-    if (wxThread::IsMain())
-        s_critsectGui->Leave();
-    WaitForSingleObject(p_internal->thread_id, INFINITE);
-    if (wxThread::IsMain())
-        s_critsectGui->Enter();
+        return wxTHREAD_MISC_ERROR;
+    }
 
 
-    GetExitCodeThread(p_internal->thread_id, &exit_code);
-    CloseHandle(p_internal->thread_id);
+    m_internal->Free();
 
 
-    p_internal->state = STATE_IDLE;
+    if ( IsDetached() )
+    {
+        delete this;
+    }
 
 
-    return (void *)exit_code;
+    return wxTHREAD_NO_ERROR;
 }
 
 }
 
-unsigned long wxThread::GetID() const
+void wxThread::Exit(ExitCode status)
 {
 {
-    return (unsigned long)p_internal->tid;
+    m_internal->Free();
+
+    if ( IsDetached() )
+    {
+        delete this;
+    }
+
+#ifdef wxUSE_BEGIN_THREAD
+    _endthreadex((unsigned)status);
+#else // !VC++
+    ::ExitThread((DWORD)status);
+#endif // VC++/!VC++
+
+    wxFAIL_MSG(wxT("Couldn't return from ExitThread()!"));
 }
 
 }
 
-bool wxThread::IsRunning() const
+// priority setting
+// ----------------
+
+void wxThread::SetPriority(unsigned int prio)
 {
 {
-    return (p_internal->state == STATE_RUNNING);
+    wxCriticalSectionLocker lock(m_critsect);
+
+    m_internal->SetPriority(prio);
 }
 
 }
 
-bool wxThread::IsAlive() const
+unsigned int wxThread::GetPriority() const
 {
 {
-    return (p_internal->state == STATE_RUNNING);
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+
+    return m_internal->GetPriority();
 }
 
 }
 
-bool wxThread::IsMain()
+unsigned long wxThread::GetId() const
 {
 {
-    return (GetCurrentThread() == s_idMainThread);
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+
+    return (unsigned long)m_internal->GetId();
 }
 
 }
 
-wxThread::wxThread()
+bool wxThread::IsRunning() const
 {
 {
-    p_internal = new wxThreadInternal();
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
 
 
-    p_internal->defer = FALSE;
-    p_internal->prio  = WXTHREAD_DEFAULT_PRIORITY;
-    p_internal->state = STATE_IDLE;
+    return m_internal->GetState() == STATE_RUNNING;
 }
 
 }
 
-wxThread::~wxThread()
+bool wxThread::IsAlive() const
 {
 {
-    Destroy();
-    Join();
-    delete p_internal;
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+
+    return (m_internal->GetState() == STATE_RUNNING) ||
+           (m_internal->GetState() == STATE_PAUSED);
 }
 
 }
 
-void wxThread::OnExit()
+bool wxThread::IsPaused() const
 {
 {
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+
+    return m_internal->GetState() == STATE_PAUSED;
+}
+
+bool wxThread::TestDestroy()
+{
+    wxCriticalSectionLocker lock((wxCriticalSection &)m_critsect); // const_cast
+
+    return m_internal->GetState() == STATE_CANCELED;
 }
 
 // ----------------------------------------------------------------------------
 }
 
 // ----------------------------------------------------------------------------
@@ -468,33 +1192,164 @@ IMPLEMENT_DYNAMIC_CLASS(wxThreadModule, wxModule)
 
 bool wxThreadModule::OnInit()
 {
 
 bool wxThreadModule::OnInit()
 {
-    s_critsectGui = new wxCriticalSection();
-    s_critsectGui->Enter();
-    s_idMainThread = GetCurrentThread();
+    // allocate TLS index for storing the pointer to the current thread
+    gs_tlsThisThread = ::TlsAlloc();
+    if ( gs_tlsThisThread == 0xFFFFFFFF )
+    {
+        // in normal circumstances it will only happen if all other
+        // TLS_MINIMUM_AVAILABLE (>= 64) indices are already taken - in other
+        // words, this should never happen
+        wxLogSysError(_("Thread module initialization failed: impossible to allocate index in thread local storage"));
+
+        return FALSE;
+    }
+
+    // main thread doesn't have associated wxThread object, so store 0 in the
+    // TLS instead
+    if ( !::TlsSetValue(gs_tlsThisThread, (LPVOID)0) )
+    {
+        ::TlsFree(gs_tlsThisThread);
+        gs_tlsThisThread = 0xFFFFFFFF;
+
+        wxLogSysError(_("Thread module initialization failed: can not store value in thread local storage"));
+
+        return FALSE;
+    }
+
+    gs_critsectWaitingForGui = new wxCriticalSection();
+
+    gs_critsectGui = new wxCriticalSection();
+    gs_critsectGui->Enter();
+
+    // no error return for GetCurrentThreadId()
+    gs_idMainThread = ::GetCurrentThreadId();
 
     return TRUE;
 }
 
 void wxThreadModule::OnExit()
 {
 
     return TRUE;
 }
 
 void wxThreadModule::OnExit()
 {
-    if ( s_critsectGui )
+    if ( !::TlsFree(gs_tlsThisThread) )
+    {
+        wxLogLastError(wxT("TlsFree failed."));
+    }
+
+    if ( gs_critsectGui )
     {
     {
-        s_critsectGui->Leave();
-        delete s_critsectGui;
-        s_critsectGui = NULL;
+        gs_critsectGui->Leave();
+        delete gs_critsectGui;
+        gs_critsectGui = NULL;
     }
     }
+
+    delete gs_critsectWaitingForGui;
+    gs_critsectWaitingForGui = NULL;
 }
 
 }
 
-// under Windows, these functions are implemented usign a critical section and
+// ----------------------------------------------------------------------------
+// under Windows, these functions are implemented using a critical section and
 // not a mutex, so the names are a bit confusing
 // not a mutex, so the names are a bit confusing
+// ----------------------------------------------------------------------------
+
 void WXDLLEXPORT wxMutexGuiEnter()
 {
 void WXDLLEXPORT wxMutexGuiEnter()
 {
-    //s_critsectGui->Enter();
+    // this would dead lock everything...
+    wxASSERT_MSG( !wxThread::IsMain(),
+                  wxT("main thread doesn't want to block in wxMutexGuiEnter()!") );
+
+    // the order in which we enter the critical sections here is crucial!!
+
+    // set the flag telling to the main thread that we want to do some GUI
+    {
+        wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
+
+        gs_nWaitingForGui++;
+    }
+
+    wxWakeUpMainThread();
+
+    // now we may block here because the main thread will soon let us in
+    // (during the next iteration of OnIdle())
+    gs_critsectGui->Enter();
 }
 
 void WXDLLEXPORT wxMutexGuiLeave()
 {
 }
 
 void WXDLLEXPORT wxMutexGuiLeave()
 {
-    //s_critsectGui->Leave();
+    wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
+
+    if ( wxThread::IsMain() )
+    {
+        gs_bGuiOwnedByMainThread = FALSE;
+    }
+    else
+    {
+        // decrement the number of threads waiting for GUI access now
+        wxASSERT_MSG( gs_nWaitingForGui > 0,
+                      wxT("calling wxMutexGuiLeave() without entering it first?") );
+
+        gs_nWaitingForGui--;
+
+        wxWakeUpMainThread();
+    }
+
+    gs_critsectGui->Leave();
+}
+
+void WXDLLEXPORT wxMutexGuiLeaveOrEnter()
+{
+    wxASSERT_MSG( wxThread::IsMain(),
+                  wxT("only main thread may call wxMutexGuiLeaveOrEnter()!") );
+
+    wxCriticalSectionLocker enter(*gs_critsectWaitingForGui);
+
+    if ( gs_nWaitingForGui == 0 )
+    {
+        // no threads are waiting for GUI - so we may acquire the lock without
+        // any danger (but only if we don't already have it)
+        if ( !wxGuiOwnedByMainThread() )
+        {
+            gs_critsectGui->Enter();
+
+            gs_bGuiOwnedByMainThread = TRUE;
+        }
+        //else: already have it, nothing to do
+    }
+    else
+    {
+        // some threads are waiting, release the GUI lock if we have it
+        if ( wxGuiOwnedByMainThread() )
+        {
+            wxMutexGuiLeave();
+        }
+        //else: some other worker thread is doing GUI
+    }
+}
+
+bool WXDLLEXPORT wxGuiOwnedByMainThread()
+{
+    return gs_bGuiOwnedByMainThread;
 }
 
 }
 
+// wake up the main thread if it's in ::GetMessage()
+void WXDLLEXPORT wxWakeUpMainThread()
+{
+    // sending any message would do - hopefully WM_NULL is harmless enough
+    if ( !::PostThreadMessage(gs_idMainThread, WM_NULL, 0, 0) )
+    {
+        // should never happen
+        wxLogLastError(wxT("PostThreadMessage(WM_NULL)"));
+    }
+}
+
+bool WXDLLEXPORT wxIsWaitingForThread()
+{
+    return gs_waitingForThread;
+}
+
+// ----------------------------------------------------------------------------
+// include common implementation code
+// ----------------------------------------------------------------------------
+
+#include "wx/thrimpl.cpp"
+
 #endif // wxUSE_THREADS
 #endif // wxUSE_THREADS
+
wxWidgets (Impactor)