X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/bee503b05f2e67035e1f45bd33e94451daeceb31..ccdcde00d9ae27ca20ff6c3c9495918a0ec725aa:/include/wx/thread.h

diff --git a/include/wx/thread.h b/include/wx/thread.h
index fb12b9ccc8..60f5c7c5c4 100644
--- a/include/wx/thread.h
+++ b/include/wx/thread.h
@@ -2,7 +2,8 @@
 // Name:        thread.h
 // Purpose:     Thread API
 // Author:      Guilhem Lavaux
-// Modified by:
+// Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads
+//              package from Olivetti & Oracle Research Laboratory)
 // Created:     04/13/98
 // RCS-ID:      $Id$
 // Copyright:   (c) Guilhem Lavaux
@@ -12,44 +13,63 @@
 #ifndef __THREADH__
 #define __THREADH__
 
-#ifdef __GNUG__
-#pragma interface "thread.h"
-#endif
-
 // ----------------------------------------------------------------------------
 // headers
 // ----------------------------------------------------------------------------
+
+// get the value of wxUSE_THREADS configuration flag
 #include "wx/setup.h"
 
 #if wxUSE_THREADS
+
+// only for wxUSE_THREADS - otherwise we'd get undefined symbols
+#ifdef __GNUG__
+    #pragma interface "thread.h"
+#endif
+
+// Windows headers define it
+#ifdef Yield
+    #undef Yield
+#endif
+
 #include "wx/module.h"
 
 // ----------------------------------------------------------------------------
 // constants
 // ----------------------------------------------------------------------------
 
-typedef enum 
+enum wxMutexError
 {
-  wxMUTEX_NO_ERROR = 0,
-  wxMUTEX_DEAD_LOCK,      // Mutex has been already locked by THE CALLING thread 
-  wxMUTEX_BUSY,           // Mutex has been already locked by ONE thread
-  wxMUTEX_UNLOCKED,
-  wxMUTEX_MISC_ERROR
-} wxMutexError;
-
-typedef enum 
+    wxMUTEX_NO_ERROR = 0,
+    wxMUTEX_DEAD_LOCK,      // Mutex has been already locked by THE CALLING thread
+    wxMUTEX_BUSY,           // Mutex has been already locked by ONE thread
+    wxMUTEX_UNLOCKED,
+    wxMUTEX_MISC_ERROR
+};
+
+enum wxThreadError
+{
+    wxTHREAD_NO_ERROR = 0,      // No error
+    wxTHREAD_NO_RESOURCE,       // No resource left to create a new thread
+    wxTHREAD_RUNNING,           // The thread is already running
+    wxTHREAD_NOT_RUNNING,       // The thread isn't running
+    wxTHREAD_KILLED,            // Thread we waited for had to be killed
+    wxTHREAD_MISC_ERROR         // Some other error
+};
+
+enum wxThreadKind
 {
-  wxTHREAD_NO_ERROR = 0,      // No error
-  wxTHREAD_NO_RESOURCE,       // No resource left to create a new thread
-  wxTHREAD_RUNNING,           // The thread is already running
-  wxTHREAD_NOT_RUNNING,       // The thread isn't running
-  wxTHREAD_MISC_ERROR         // Some other error
-} wxThreadError;
-
-/* defines the interval of priority. */
-#define WXTHREAD_MIN_PRIORITY     0
-#define WXTHREAD_DEFAULT_PRIORITY 50
-#define WXTHREAD_MAX_PRIORITY     100
+    wxTHREAD_DETACHED,
+    wxTHREAD_JOINABLE
+};
+
+// defines the interval of priority
+enum
+{
+    WXTHREAD_MIN_PRIORITY      = 0u,
+    WXTHREAD_DEFAULT_PRIORITY  = 50u,
+    WXTHREAD_MAX_PRIORITY      = 100u
+};
 
 // ----------------------------------------------------------------------------
 // A mutex object is a synchronization object whose state is set to signaled
@@ -60,29 +80,34 @@ typedef enum
 
 // you should consider wxMutexLocker whenever possible instead of directly
 // working with wxMutex class - it is safer
+class WXDLLEXPORT wxConditionInternal;
 class WXDLLEXPORT wxMutexInternal;
-class WXDLLEXPORT wxMutex 
+class WXDLLEXPORT wxMutex
 {
 public:
-  // constructor & destructor 
-  wxMutex();
-  ~wxMutex();
+    // constructor & destructor
+    wxMutex();
+    ~wxMutex();
 
-  // Lock the mutex.
-  wxMutexError Lock();
-  // Try to lock the mutex: if it can't, returns immediately with an error.
-  wxMutexError TryLock();
-  // Unlock the mutex.
-  wxMutexError Unlock();
+    // Lock the mutex.
+    wxMutexError Lock();
+    // Try to lock the mutex: if it can't, returns immediately with an error.
+    wxMutexError TryLock();
+    // Unlock the mutex.
+    wxMutexError Unlock();
 
-  // Returns true if the mutex is locked.
-  bool IsLocked() const { return (m_locked > 0); }
+    // Returns true if the mutex is locked.
+    bool IsLocked() const { return (m_locked > 0); }
 
 protected:
-  friend class wxCondition;
+    // no assignment operator nor copy ctor
+    wxMutex(const wxMutex&);
+    wxMutex& operator=(const wxMutex&);
+
+    int m_locked;
+    wxMutexInternal *m_internal;
 
-  int m_locked;
-  wxMutexInternal *p_internal;
+    friend class wxConditionInternal;
 };
 
 // a helper class which locks the mutex in the ctor and unlocks it in the dtor:
@@ -92,157 +117,373 @@ class WXDLLEXPORT wxMutexLocker
 {
 public:
     // lock the mutex in the ctor
-    wxMutexLocker(wxMutex *mutex)
-        { m_isOk = mutex && ((m_mutex = mutex)->Lock() == wxMUTEX_NO_ERROR); }
+    wxMutexLocker(wxMutex& mutex) : m_mutex(mutex)
+        { m_isOk = m_mutex.Lock() == wxMUTEX_NO_ERROR; }
 
     // returns TRUE if mutex was successfully locked in ctor
-    bool IsOk() const { return m_isOk; }
+    bool IsOk() const
+        { return m_isOk; }
 
     // unlock the mutex in dtor
-    ~wxMutexLocker() { if ( IsOk() ) m_mutex->Unlock(); }
+    ~wxMutexLocker()
+        { if ( IsOk() ) m_mutex.Unlock(); }
 
 private:
+    // no assignment operator nor copy ctor
+    wxMutexLocker(const wxMutexLocker&);
+    wxMutexLocker& operator=(const wxMutexLocker&);
+
     bool     m_isOk;
-    wxMutex *m_mutex;
+    wxMutex& m_mutex;
 };
 
-#ifdef __WXMSW__
-
 // ----------------------------------------------------------------------------
 // Critical section: this is the same as mutex but is only visible to the
 // threads of the same process. For the platforms which don't have native
 // support for critical sections, they're implemented entirely in terms of
-// mutexes
+// mutexes.
+//
+// NB: wxCriticalSection object does not allocate any memory in its ctor
+//     which makes it possible to have static globals of this class
 // ----------------------------------------------------------------------------
 
+class WXDLLEXPORT wxCriticalSectionInternal;
+
+// in order to avoid any overhead under platforms where critical sections are
+// just mutexes make all wxCriticalSection class functions inline
+#if !defined(__WXMSW__) && !defined(__WXPM__)
+    #define WXCRITICAL_INLINE   inline
+
+    #define wxCRITSECT_IS_MUTEX 1
+#else // MSW || OS2
+    #define WXCRITICAL_INLINE
+
+    #define wxCRITSECT_IS_MUTEX 0
+#endif // MSW/!MSW
+
 // you should consider wxCriticalSectionLocker whenever possible instead of
 // directly working with wxCriticalSection class - it is safer
-class WXDLLEXPORT wxCriticalSectionInternal;
 class WXDLLEXPORT wxCriticalSection
 {
 public:
     // ctor & dtor
-    wxCriticalSection();
-    ~wxCriticalSection();
+    WXCRITICAL_INLINE wxCriticalSection();
+    WXCRITICAL_INLINE ~wxCriticalSection();
 
     // enter the section (the same as locking a mutex)
-    void Enter();
+    WXCRITICAL_INLINE void Enter();
     // leave the critical section (same as unlocking a mutex)
-    void Leave();
+    WXCRITICAL_INLINE void Leave();
 
 private:
+    // no assignment operator nor copy ctor
+    wxCriticalSection(const wxCriticalSection&);
+    wxCriticalSection& operator=(const wxCriticalSection&);
+
+#if wxCRITSECT_IS_MUTEX
+    wxMutex m_mutex;
+#elif defined(__WXMSW__)
+    // we can't allocate any memory in the ctor, so use placement new -
+    // unfortunately, we have to hardcode the sizeof() here because we can't
+    // include windows.h from this public header
+    char m_buffer[24];
+#elif !defined(__WXPM__)
     wxCriticalSectionInternal *m_critsect;
+#else
+    // nothing for OS/2
+#endif // !Unix/Unix
 };
 
+// keep your preprocessor name space clean
+#undef WXCRITICAL_INLINE
+
 // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
 // to th mutexes
 class WXDLLEXPORT wxCriticalSectionLocker
 {
 public:
-    wxCriticalSectionLocker(wxCriticalSection& critsect) : m_critsect(critsect)
-        { m_critsect.Enter(); }
-    ~wxCriticalSectionLocker()
-        { m_critsect.Leave(); }
+    inline wxCriticalSectionLocker(wxCriticalSection& critsect);
+    inline ~wxCriticalSectionLocker();
 
 private:
+    // no assignment operator nor copy ctor
+    wxCriticalSectionLocker(const wxCriticalSectionLocker&);
+    wxCriticalSectionLocker& operator=(const wxCriticalSectionLocker&);
+
     wxCriticalSection& m_critsect;
 };
 
-#endif
-
 // ----------------------------------------------------------------------------
-// Condition handler.
+// wxCondition models a POSIX condition variable which allows one (or more)
+// thread(s) to wait until some condition is fulfilled
 // ----------------------------------------------------------------------------
 
-class wxConditionInternal;
-class WXDLLEXPORT wxCondition 
+class WXDLLEXPORT wxCondition
 {
 public:
-  // constructor & destructor
-  wxCondition();
-  ~wxCondition();
-
-  // Waits indefinitely.
-  void Wait(wxMutex& mutex);
-  // Waits until a signal is raised or the timeout is elapsed.
-  bool Wait(wxMutex& mutex, unsigned long sec, unsigned long nsec);
-  // Raises a signal: only one "Waiter" is released.
-  void Signal();
-  // Broadcasts to all "Waiters".
-  void Broadcast();
+    // constructor and destructor
+
+    // Each wxCondition object is associated with with a wxMutex object The
+    // mutex object MUST be locked before calling Wait()
+    wxCondition(wxMutex& mutex);
+
+    // dtor is not virtual, don't use this class polymorphically
+    ~wxCondition();
+
+    // NB: the associated mutex MUST be locked beforehand by the calling thread
+    // 
+    // it atomically releases the lock on the associated mutex
+    // and starts waiting to be woken up by a Signal()/Broadcast()
+    // once its signaled, then it will wait until it can reacquire
+    // the lock on the associated mutex object, before returning.
+    void Wait();
+
+    // exactly as Wait() except that it may also return if the specified
+    // timeout ellapses even if the condition hasn't been signalled: in this
+    // case, the return value is FALSE, otherwise (i.e. in case of a normal
+    // return) it is TRUE
+    // 
+    // the timeeout parameter specifies a interval that needs to be waited in
+    // milliseconds
+    bool Wait( unsigned long timeout_millis );
+
+    // NB: the associated mutex may or may not be locked by the calling thread
+    //
+    // this method unblocks one thread if any are blocking on the condition.
+    // if no thread is blocking in Wait(), then the signal is NOT remembered
+    // The thread which was blocking on Wait(), will then reacquire the lock
+    // on the associated mutex object before returning
+    void Signal();
+
+    // NB: the associated mutex may or may not be locked by the calling thread
+    //
+    // this method unblocks all threads if any are blocking on the condition.
+    // if no thread is blocking in Wait(), then the signal is NOT remembered
+    // The threads which were blocking on Wait(), will then reacquire the lock
+    // on the associated mutex object before returning.
+    void Broadcast();
 
 private:
-  wxConditionInternal *p_internal;
+    wxConditionInternal *m_internal;
 };
 
 // ----------------------------------------------------------------------------
-// Thread management class
+// wxSemaphore: a counter limiting the number of threads concurrently accessing
+//              a shared resource
 // ----------------------------------------------------------------------------
 
-class wxThreadInternal;
-class WXDLLEXPORT wxThread 
+class WXDLLEXPORT wxSemaphoreInternal;
+class WXDLLEXPORT wxSemaphore
 {
 public:
-  // constructor & destructor.
-  wxThread();
-  virtual ~wxThread();
+    // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
+    // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
+    wxSemaphore( int initialcount = 0, int maxcount = 0 );
 
-  // Create a new thread, this method should check there is only one thread
-  // running by object.
-  wxThreadError Create();
+    // dtor is not virtual, don't use this class polymorphically
+    ~wxSemaphore();
 
-  // Destroys the thread immediately if the defer flag isn't true.
-  wxThreadError Destroy();
+    // wait indefinitely, until the semaphore count goes beyond 0
+    // and then decrement it and return (this method might have been called
+    // Acquire())
+    void Wait();
 
-  // Pause a running thread
-  wxThreadError Pause();
+    // same as Wait(), but does not block, returns TRUE if successful and
+    // FALSE if the count is zero
+    bool TryWait();
 
-  // Resume a paused thread
-  wxThreadError Resume();
+    // same as Wait(), but as a timeout limit, returns TRUE if the semaphore
+    // was acquired and FALSE if the timeout has ellapsed
+    bool Wait( unsigned long timeout_millis );
 
-  // Switches on the defer flag.
-  void DeferDestroy(bool on);
+    // increments the semaphore count and signals one of the waiting threads
+    void Post();
 
-  // Waits for the termination of the thread.
-  void *Join();
+private:
+    wxSemaphoreInternal *m_internal;
+};
 
-  // Sets the priority to "prio". (Warning: The priority can only be set before
-  // the thread is created)
-  void SetPriority(int prio);
-  // Get the current priority.
-  int GetPriority() const;
+// ----------------------------------------------------------------------------
+// wxThread: class encpasulating a thread of execution
+// ----------------------------------------------------------------------------
 
-  // Get the thread ID
-  unsigned long GetID() const;
+// there are two different kinds of threads: joinable and detached (default)
+// ones. Only joinable threads can return a return code and only detached
+// threads auto-delete themselves - the user should delete the joinable
+// threads manually.
 
-  // Returns true if the thread is alive.
-  bool IsAlive() const;
-  // Returns true if the thread is running (not paused, not killed).
-  bool IsRunning() const;
-  // Returns true if the thread is suspended
-  bool IsPaused() const { return IsAlive() && !IsRunning(); }
+// NB: in the function descriptions the words "this thread" mean the thread
+//     created by the wxThread object while "main thread" is the thread created
+//     during the process initialization (a.k.a. the GUI thread)
 
-  // Returns true if current thread is the main thread (aka the GUI thread)
-  static bool IsMain();
+// On VMS thread pointers are 64 bits (also needed for other systems???
+#ifdef __VMS
+   typedef unsigned long long wxThreadIdType;
+#else
+   typedef unsigned long wxThreadIdType;
+#endif
 
-  // Called when thread exits.
-  virtual void OnExit();
+class wxThreadInternal;
+class WXDLLEXPORT wxThread
+{
+public:
+    // the return type for the thread function
+    typedef void *ExitCode;
+
+    // static functions
+        // Returns the wxThread object for the calling thread. NULL is returned
+        // if the caller is the main thread (but it's recommended to use
+        // IsMain() and only call This() for threads other than the main one
+        // because NULL is also returned on error). If the thread wasn't
+        // created with wxThread class, the returned value is undefined.
+    static wxThread *This();
+
+        // Returns true if current thread is the main thread.
+    static bool IsMain();
+
+        // Release the rest of our time slice leting the other threads run
+    static void Yield();
+
+        // Sleep during the specified period of time in milliseconds
+        //
+        // NB: at least under MSW worker threads can not call ::wxSleep()!
+    static void Sleep(unsigned long milliseconds);
+
+        // get the number of system CPUs - useful with SetConcurrency()
+        // (the "best" value for it is usually number of CPUs + 1)
+        //
+        // Returns -1 if unknown, number of CPUs otherwise
+    static int GetCPUCount();
+
+        // Get the platform specific thread ID and return as a long.  This
+        // can be used to uniquely identify threads, even if they are not
+        // wxThreads.  This is used by wxPython.
+   static wxThreadIdType GetCurrentId();
+
+        // sets the concurrency level: this is, roughly, the number of threads
+        // the system tries to schedule to run in parallel. 0 means the
+        // default value (usually acceptable, but may not yield the best
+        // performance for this process)
+        //
+        // Returns TRUE on success, FALSE otherwise (if not implemented, for
+        // example)
+    static bool SetConcurrency(size_t level);
+
+    // constructor only creates the C++ thread object and doesn't create (or
+    // start) the real thread
+    wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
+
+    // functions that change the thread state: all these can only be called
+    // from _another_ thread (typically the thread that created this one, e.g.
+    // the main thread), not from the thread itself
+
+        // create a new thread and optionally set the stack size on
+        // platforms that support that - call Run() to start it
+        // (special cased for watcom which won't accept 0 default)
+
+    wxThreadError Create(unsigned int stackSize = 0);
+
+        // starts execution of the thread - from the moment Run() is called
+        // the execution of wxThread::Entry() may start at any moment, caller
+        // shouldn't suppose that it starts after (or before) Run() returns.
+    wxThreadError Run();
+
+        // stops the thread if it's running and deletes the wxThread object if
+        // this is a detached thread freeing its memory - otherwise (for
+        // joinable threads) you still need to delete wxThread object
+        // yourself.
+        //
+        // this function only works if the thread calls TestDestroy()
+        // periodically - the thread will only be deleted the next time it
+        // does it!
+        //
+        // will fill the rc pointer with the thread exit code if it's !NULL
+    wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
+
+        // waits for a joinable thread to finish and returns its exit code
+        //
+        // Returns (ExitCode)-1 on error (for example, if the thread is not
+        // joinable)
+    ExitCode Wait();
+
+        // kills the thread without giving it any chance to clean up - should
+        // not be used in normal circumstances, use Delete() instead. It is a
+        // dangerous function that should only be used in the most extreme
+        // cases!
+        //
+        // The wxThread object is deleted by Kill() if the thread is
+        // detachable, but you still have to delete it manually for joinable
+        // threads.
+    wxThreadError Kill();
+
+        // pause a running thread: as Delete(), this only works if the thread
+        // calls TestDestroy() regularly
+    wxThreadError Pause();
+
+        // resume a paused thread
+    wxThreadError Resume();
+
+    // priority
+        // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
+        //
+        // NB: the priority can only be set before the thread is created
+    void SetPriority(unsigned int prio);
+
+        // Get the current priority.
+    unsigned int GetPriority() const;
+
+    // thread status inquiries
+        // Returns true if the thread is alive: i.e. running or suspended
+    bool IsAlive() const;
+        // Returns true if the thread is running (not paused, not killed).
+    bool IsRunning() const;
+        // Returns true if the thread is suspended
+    bool IsPaused() const;
+
+        // is the thread of detached kind?
+    bool IsDetached() const { return m_isDetached; }
+
+    // Get the thread ID - a platform dependent number which uniquely
+    // identifies a thread inside a process
+    wxThreadIdType GetId() const;
+
+    // called when the thread exits - in the context of this thread
+    //
+    // NB: this function will not be called if the thread is Kill()ed
+    virtual void OnExit() { }
+
+    // dtor is public, but the detached threads should never be deleted - use
+    // Delete() instead (or leave the thread terminate by itself)
+    virtual ~wxThread();
 
 protected:
-  // Returns TRUE if the thread was asked to terminate
-  bool TestDestroy();
+    // Returns TRUE if the thread was asked to terminate: this function should
+    // be called by the thread from time to time, otherwise the main thread
+    // will be left forever in Delete()!
+    bool TestDestroy();
 
-  // Exits from the current thread.
-  void Exit(void *status = NULL);
+    // exits from the current thread - can be called only from this thread
+    void Exit(ExitCode exitcode = 0);
 
-private:
-  // Entry point for the thread.
-  virtual void *Entry() = 0;
+    // entry point for the thread - called by Run() and executes in the context
+    // of this thread.
+    virtual void *Entry() = 0;
 
 private:
-  friend class wxThreadInternal;
+    // no copy ctor/assignment operator
+    wxThread(const wxThread&);
+    wxThread& operator=(const wxThread&);
+
+    friend class wxThreadInternal;
+
+    // the (platform-dependent) thread class implementation
+    wxThreadInternal *m_internal;
+
+    // protects access to any methods of wxThreadInternal object
+    wxCriticalSection m_critsect;
 
-  wxThreadInternal *p_internal;
+    // true if the thread is detached, false if it is joinable
+    bool m_isDetached;
 };
 
 // ----------------------------------------------------------------------------
@@ -253,26 +494,28 @@ private:
 void WXDLLEXPORT wxMutexGuiEnter();
 void WXDLLEXPORT wxMutexGuiLeave();
 
-// implementation only
-#ifdef __WXMSW__
-    // unlock GUI if there are threads waiting for and lock it back when
-    // there are no more of them - should be called periodically by the main
-    // thread
-    void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
-
-    // returns TRUE if the main thread has GUI lock
-    inline bool WXDLLEXPORT wxGuiOwnedByMainThread();
-
-    // wakes up the main thread if it's sleeping inside ::GetMessage()
-    inline void WXDLLEXPORT wxWakeUpMainThread();
-#endif // MSW
+// macros for entering/leaving critical sections which may be used without
+// having to take them inside "#if wxUSE_THREADS"
+#define wxENTER_CRIT_SECT(cs)   (cs).Enter()
+#define wxLEAVE_CRIT_SECT(cs)   (cs).Leave()
+#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
+#define wxCRIT_SECT_LOCKER(name, cs)  wxCriticalSectionLocker name(cs)
 
 #else // !wxUSE_THREADS
 
+#include "wx/defs.h" // for WXDLLEXPORT
+
 // no thread support
 inline void WXDLLEXPORT wxMutexGuiEnter() { }
 inline void WXDLLEXPORT wxMutexGuiLeave() { }
 
+// macros for entering/leaving critical sections which may be used without
+// having to take them inside "#if wxUSE_THREADS"
+#define wxENTER_CRIT_SECT(cs)
+#define wxLEAVE_CRIT_SECT(cs)
+#define wxCRIT_SECT_DECLARE(cs)
+#define wxCRIT_SECT_LOCKER(name, cs)
+
 #endif // wxUSE_THREADS
 
 // automatically unlock GUI mutex in dtor
@@ -283,4 +526,76 @@ public:
    ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
 };
 
+// -----------------------------------------------------------------------------
+// implementation only until the end of file
+// -----------------------------------------------------------------------------
+
+#if wxUSE_THREADS
+
+#if defined(__WXMSW__)
+    // unlock GUI if there are threads waiting for and lock it back when
+    // there are no more of them - should be called periodically by the main
+    // thread
+    extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+
+    // returns TRUE if the main thread has GUI lock
+    extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
+
+    // wakes up the main thread if it's sleeping inside ::GetMessage()
+    extern void WXDLLEXPORT wxWakeUpMainThread();
+
+    // return TRUE if the main thread is waiting for some other to terminate:
+    // wxApp then should block all "dangerous" messages
+    extern bool WXDLLEXPORT wxIsWaitingForThread();
+#elif defined(__WXMAC__)
+   extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+
+    // returns TRUE if the main thread has GUI lock
+    extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
+
+    // wakes up the main thread if it's sleeping inside ::GetMessage()
+    extern void WXDLLEXPORT wxWakeUpMainThread();
+
+    // return TRUE if the main thread is waiting for some other to terminate:
+    // wxApp then should block all "dangerous" messages
+    extern bool WXDLLEXPORT wxIsWaitingForThread();
+
+    // implement wxCriticalSection using mutexes
+    inline wxCriticalSection::wxCriticalSection() { }
+    inline wxCriticalSection::~wxCriticalSection() { }
+
+    inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
+    inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
+#elif defined(__WXPM__)
+    // unlock GUI if there are threads waiting for and lock it back when
+    // there are no more of them - should be called periodically by the main
+    // thread
+    extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
+
+    // returns TRUE if the main thread has GUI lock
+    extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
+
+    // return TRUE if the main thread is waiting for some other to terminate:
+    // wxApp then should block all "dangerous" messages
+    extern bool WXDLLEXPORT wxIsWaitingForThread();
+
+#else // !MSW && !PM
+    // implement wxCriticalSection using mutexes
+    inline wxCriticalSection::wxCriticalSection() { }
+    inline wxCriticalSection::~wxCriticalSection() { }
+
+    inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
+    inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
+#endif // MSW/!MSW
+
+    // we can define these inline functions now (they should be defined after
+    // wxCriticalSection::Enter/Leave)
+    inline
+    wxCriticalSectionLocker:: wxCriticalSectionLocker(wxCriticalSection& cs)
+        : m_critsect(cs) { m_critsect.Enter(); }
+    inline
+    wxCriticalSectionLocker::~wxCriticalSectionLocker() { m_critsect.Leave(); }
+#endif // wxUSE_THREADS
+
 #endif // __THREADH__
+