Rebake from clean wx tree.

[wxWidgets.git] / include / wx / thread.h

diff --git a/include/wx/thread.h b/include/wx/thread.h
index 99091a44abdaa58a749be6fa6beb8bfceb1c8f22..7e85ae23149f227d8786f027fb12ccfc5b5fe9be 100644 (file)
--- a/include/wx/thread.h
+++ b/include/wx/thread.h
@@ -1,159 +1,833 @@
 /////////////////////////////////////////////////////////////////////////////
 /////////////////////////////////////////////////////////////////////////////

-// Name:        thread.h
+// Name:        wx/thread.h

 // Purpose:     Thread API
 // Author:      Guilhem Lavaux
 // 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
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 // Created:     04/13/98
 // RCS-ID:      $Id$
 // Copyright:   (c) Guilhem Lavaux
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 

-#ifndef __THREADH__
-#define __THREADH__
+#ifndef _WX_THREAD_H_
+#define _WX_THREAD_H_

 
 

-#ifdef __GNUG__
-#pragma interface "thread.h"
-#endif
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// get the value of wxUSE_THREADS configuration flag
+#include "wx/defs.h"
+
+#if wxUSE_THREADS
+
+// ----------------------------------------------------------------------------
+// constants
+// ----------------------------------------------------------------------------
+
+enum wxMutexError
+{
+    wxMUTEX_NO_ERROR = 0,   // operation completed successfully
+    wxMUTEX_INVALID,        // mutex hasn't been initialized
+    wxMUTEX_DEAD_LOCK,      // mutex is already locked by the calling thread
+    wxMUTEX_BUSY,           // mutex is already locked by another thread
+    wxMUTEX_UNLOCKED,       // attempt to unlock a mutex which is not locked
+    wxMUTEX_TIMEOUT,        // LockTimeout() has timed out
+    wxMUTEX_MISC_ERROR      // any other error
+};
+
+enum wxCondError
+{
+    wxCOND_NO_ERROR = 0,
+    wxCOND_INVALID,
+    wxCOND_TIMEOUT,         // WaitTimeout() has timed out
+    wxCOND_MISC_ERROR
+};
+
+enum wxSemaError
+{
+    wxSEMA_NO_ERROR = 0,
+    wxSEMA_INVALID,         // semaphore hasn't been initialized successfully
+    wxSEMA_BUSY,            // returned by TryWait() if Wait() would block
+    wxSEMA_TIMEOUT,         // returned by WaitTimeout()
+    wxSEMA_OVERFLOW,        // Post() would increase counter past the max
+    wxSEMA_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_DETACHED,
+    wxTHREAD_JOINABLE
+};
+
+// defines the interval of priority
+enum
+{
+    WXTHREAD_MIN_PRIORITY      = 0u,
+    WXTHREAD_DEFAULT_PRIORITY  = 50u,
+    WXTHREAD_MAX_PRIORITY      = 100u
+};
+
+// There are 2 types of mutexes: normal mutexes and recursive ones. The attempt
+// to lock a normal mutex by a thread which already owns it results in
+// undefined behaviour (it always works under Windows, it will almost always
+// result in a deadlock under Unix). Locking a recursive mutex in such
+// situation always succeeds and it must be unlocked as many times as it has
+// been locked.
+//
+// However recursive mutexes have several important drawbacks: first, in the
+// POSIX implementation, they're less efficient. Second, and more importantly,
+// they CAN NOT BE USED WITH CONDITION VARIABLES under Unix! Using them with
+// wxCondition will work under Windows and some Unices (notably Linux) but will
+// deadlock under other Unix versions (e.g. Solaris). As it might be difficult
+// to ensure that a recursive mutex is not used with wxCondition, it is a good
+// idea to avoid using recursive mutexes at all. Also, the last problem with
+// them is that some (older) Unix versions don't support this at all -- which
+// results in a configure warning when building and a deadlock when using them.
+enum wxMutexType
+{
+    // normal mutex: try to always use this one
+    wxMUTEX_DEFAULT,

 
 

-#include "wx/object.h"
-#include "wx/setup.h"
-
-typedef enum {
-  MUTEX_NO_ERROR=0,
-  MUTEX_DEAD_LOCK,             // Mutex has been already locked by THE CALLING thread 
-  MUTEX_BUSY,                  // Mutex has been already locked by ONE thread
-  MUTEX_UNLOCKED
-} wxMutexError;
-
-typedef enum {
-  THREAD_NO_ERROR=0,           // No error
-  THREAD_NO_RESOURCE,          // No resource left to create a new thread
-  THREAD_RUNNING,              // The thread is already running
-  THREAD_NOT_RUNNING,          // The thread isn't running
-  THREAD_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
-
-// ---------------------------------------------------------------------------
-// Mutex handler
-class WXDLLEXPORT wxMutexInternal;
-class WXDLLEXPORT wxMutex {
+    // recursive mutex: don't use these ones with wxCondition
+    wxMUTEX_RECURSIVE
+};
+
+// forward declarations
+class WXDLLIMPEXP_FWD_BASE wxThreadHelper;
+class WXDLLIMPEXP_FWD_BASE wxConditionInternal;
+class WXDLLIMPEXP_FWD_BASE wxMutexInternal;
+class WXDLLIMPEXP_FWD_BASE wxSemaphoreInternal;
+class WXDLLIMPEXP_FWD_BASE wxThreadInternal;
+
+// ----------------------------------------------------------------------------
+// A mutex object is a synchronization object whose state is set to signaled
+// when it is not owned by any thread, and nonsignaled when it is owned. Its
+// name comes from its usefulness in coordinating mutually-exclusive access to
+// a shared resource. Only one thread at a time can own a mutex object.
+// ----------------------------------------------------------------------------
+
+// you should consider wxMutexLocker whenever possible instead of directly
+// working with wxMutex class - it is safer
+class WXDLLIMPEXP_BASE wxMutex
+{

 public:
 public:

-  // 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();
-
-  // Returns true if the mutex is locked.
-  bool IsLocked() const { return (m_locked > 0); }
+    // constructor & destructor
+    // ------------------------
+
+    // create either default (always safe) or recursive mutex
+    wxMutex(wxMutexType mutexType = wxMUTEX_DEFAULT);
+
+    // destroys the mutex kernel object
+    ~wxMutex();
+
+    // test if the mutex has been created successfully
+    bool IsOk() const;
+
+    // mutex operations
+    // ----------------
+
+    // Lock the mutex, blocking on it until it is unlocked by the other thread.
+    // The result of locking a mutex already locked by the current thread
+    // depend on the mutex type.
+    //
+    // The caller must call Unlock() later if Lock() returned wxMUTEX_NO_ERROR.
+    wxMutexError Lock();
+
+    // Same as Lock() but return wxMUTEX_TIMEOUT if the mutex can't be locked
+    // during the given number of milliseconds
+    wxMutexError LockTimeout(unsigned long ms);
+
+    // Try to lock the mutex: if it is currently locked, return immediately
+    // with an error. Otherwise the caller must call Unlock().
+    wxMutexError TryLock();
+
+    // Unlock the mutex. It is an error to unlock an already unlocked mutex
+    wxMutexError Unlock();
+

 protected:
 protected:

-  friend class wxCondition;
+    wxMutexInternal *m_internal;
+
+    friend class wxConditionInternal;

 
 

-  int m_locked;
-  wxMutexInternal *p_internal;
+    wxDECLARE_NO_COPY_CLASS(wxMutex);

 };
 
 };
 

-// ---------------------------------------------------------------------------
-// Condition handler.
-class wxConditionInternal;
-class WXDLLEXPORT wxCondition {
+// a helper class which locks the mutex in the ctor and unlocks it in the dtor:
+// this ensures that mutex is always unlocked, even if the function returns or
+// throws an exception before it reaches the end
+class WXDLLIMPEXP_BASE wxMutexLocker
+{

 public:
 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();
+    // lock the mutex in the ctor
+    wxMutexLocker(wxMutex& mutex)
+        : m_isOk(false), 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; }
+
+    // unlock the mutex in dtor
+    ~wxMutexLocker()
+        { if ( IsOk() ) m_mutex.Unlock(); }
+

 private:
 private:

-  wxConditionInternal *p_internal;
+    // no assignment operator nor copy ctor
+    wxMutexLocker(const wxMutexLocker&);
+    wxMutexLocker& operator=(const wxMutexLocker&);
+
+    bool     m_isOk;
+    wxMutex& m_mutex;

 };
 
 };
 

-// ---------------------------------------------------------------------------
-// Thread management class
-class wxThreadInternal;
-class WXDLLEXPORT wxThread {
+// ----------------------------------------------------------------------------
+// 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.
+//
+// NB: wxCriticalSection object does not allocate any memory in its ctor
+//     which makes it possible to have static globals of this class
+// ----------------------------------------------------------------------------
+
+// in order to avoid any overhead under platforms where critical sections are
+// just mutexes make all wxCriticalSection class functions inline
+#if !defined(__WXMSW__)
+    #define wxCRITSECT_IS_MUTEX 1
+
+    #define wxCRITSECT_INLINE WXEXPORT inline
+#else // MSW
+    #define wxCRITSECT_IS_MUTEX 0
+
+    #define wxCRITSECT_INLINE
+#endif // MSW/!MSW
+
+enum wxCriticalSectionType
+{
+    // recursive critical section
+    wxCRITSEC_DEFAULT,
+
+    // non-recursive critical section
+    wxCRITSEC_NON_RECURSIVE
+};
+
+// you should consider wxCriticalSectionLocker whenever possible instead of
+// directly working with wxCriticalSection class - it is safer
+class WXDLLIMPEXP_BASE wxCriticalSection
+{

 public:
 public:

-  // constructor & destructor.
-  wxThread();
-  virtual ~wxThread();
+    // ctor & dtor
+    wxCRITSECT_INLINE wxCriticalSection( wxCriticalSectionType critSecType = wxCRITSEC_DEFAULT );
+    wxCRITSECT_INLINE ~wxCriticalSection();
+    // enter the section (the same as locking a mutex)
+    wxCRITSECT_INLINE void Enter();

 
 

-  // Create a new thread, this method should check there is only one thread
-  // running by object.
-  wxThreadError Create();
+    // leave the critical section (same as unlocking a mutex)
+    wxCRITSECT_INLINE void Leave();

 
 

-  // Destroys the thread immediately if the defer flag isn't true.
-  wxThreadError Destroy();
+private:
+#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 and we also have to use the
+    // union to force the correct (i.e. maximal) alignment
+    //
+    // if CRITICAL_SECTION size changes in Windows, you'll get an assert from
+    // thread.cpp and will need to increase the buffer size
+    //
+    // finally, we need this typedef instead of declaring m_buffer directly
+    // because otherwise the assert mentioned above wouldn't compile with some
+    // compilers (notably CodeWarrior 8)
+#ifdef __WIN64__
+    typedef char wxCritSectBuffer[40];
+#else // __WIN32__
+    typedef char wxCritSectBuffer[24];
+#endif
+    union
+    {
+        unsigned long m_dummy1;
+        void *m_dummy2;

 
 

-  // Pause a running thread
-  wxThreadError Pause();
+        wxCritSectBuffer m_buffer;
+    };
+#endif // Unix&OS2/Win32

 
 

-  // Resume a paused thread
-  wxThreadError Resume();
+    wxDECLARE_NO_COPY_CLASS(wxCriticalSection);
+};
+
+#if wxCRITSECT_IS_MUTEX
+    // implement wxCriticalSection using mutexes
+    inline wxCriticalSection::wxCriticalSection( wxCriticalSectionType critSecType )
+       : m_mutex( critSecType == wxCRITSEC_DEFAULT ? wxMUTEX_RECURSIVE : wxMUTEX_DEFAULT )  { }
+    inline wxCriticalSection::~wxCriticalSection() { }
+
+    inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
+    inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
+#endif // wxCRITSECT_IS_MUTEX
+
+#undef wxCRITSECT_INLINE
+#undef wxCRITSECT_IS_MUTEX
+
+// wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
+// to mutexes
+class WXDLLIMPEXP_BASE wxCriticalSectionLocker
+{
+public:
+    wxCriticalSectionLocker(wxCriticalSection& cs)
+        : m_critsect(cs)
+    {
+        m_critsect.Enter();
+    }
+
+    ~wxCriticalSectionLocker()
+    {
+        m_critsect.Leave();
+    }
+
+private:
+    wxCriticalSection& m_critsect;
+
+    wxDECLARE_NO_COPY_CLASS(wxCriticalSectionLocker);
+};

 
 

-  // Switches on the defer flag.
-  void DeferDestroy(bool on);
+// ----------------------------------------------------------------------------
+// wxCondition models a POSIX condition variable which allows one (or more)
+// thread(s) to wait until some condition is fulfilled
+// ----------------------------------------------------------------------------

 
 

-  // Waits for the termination of the thread.
-  void *Join();
+class WXDLLIMPEXP_BASE wxCondition
+{
+public:
+    // Each wxCondition object is associated with a (single) 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();
+
+    // return true if the condition has been created successfully
+    bool IsOk() const;
+
+    // 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.
+    wxCondError Wait();
+
+    // exactly as Wait() except that it may also return if the specified
+    // timeout elapses 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 timeout parameter specifies an interval that needs to be waited for
+    // in milliseconds
+    wxCondError WaitTimeout(unsigned long milliseconds);
+
+    // 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
+    wxCondError Signal();

 
 

-  // 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;
+    // 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.
+    wxCondError Broadcast();

 
 

-  // Get the thread ID
-  unsigned long GetID() const;

 
 

-  // 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 the main thread (aka the GUI thread).
-  static bool IsMain();
+#if WXWIN_COMPATIBILITY_2_6
+    // deprecated version, don't use
+    wxDEPRECATED( bool Wait(unsigned long milliseconds) );
+#endif // WXWIN_COMPATIBILITY_2_6
+
+private:
+    wxConditionInternal *m_internal;
+
+    wxDECLARE_NO_COPY_CLASS(wxCondition);
+};
+
+#if WXWIN_COMPATIBILITY_2_6
+    inline bool wxCondition::Wait(unsigned long milliseconds)
+        { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; }
+#endif // WXWIN_COMPATIBILITY_2_6
+
+// ----------------------------------------------------------------------------
+// wxSemaphore: a counter limiting the number of threads concurrently accessing
+//              a shared resource
+// ----------------------------------------------------------------------------
+
+class WXDLLIMPEXP_BASE wxSemaphore
+{
+public:
+    // 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 );
+
+    // dtor is not virtual, don't use this class polymorphically
+    ~wxSemaphore();
+
+    // return true if the semaphore has been created successfully
+    bool IsOk() const;
+
+    // wait indefinitely, until the semaphore count goes beyond 0
+    // and then decrement it and return (this method might have been called
+    // Acquire())
+    wxSemaError Wait();
+
+    // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if
+    // successful and wxSEMA_BUSY if the count is currently zero
+    wxSemaError TryWait();
+
+    // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the
+    // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has elapsed
+    wxSemaError WaitTimeout(unsigned long milliseconds);
+
+    // increments the semaphore count and signals one of the waiting threads
+    wxSemaError Post();
+
+private:
+    wxSemaphoreInternal *m_internal;
+
+    wxDECLARE_NO_COPY_CLASS(wxSemaphore);
+};
+
+// ----------------------------------------------------------------------------
+// wxThread: class encapsulating a thread of execution
+// ----------------------------------------------------------------------------
+
+// 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.
+
+// 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)
+
+// 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
+
+class WXDLLIMPEXP_BASE 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();

 
 

-  // Called when thread exits.
-  virtual void OnExit();
+        // Returns true if current thread is the main thread.
+        //
+        // Notice that it also returns true if main thread id hadn't been
+        // initialized yet on the assumption that it's too early in wx startup
+        // process for any other threads to have been created in this case.
+    static bool IsMain()
+    {
+        return !ms_idMainThread || GetCurrentId() == ms_idMainThread;
+    }
+
+        // Return the main thread id
+    static wxThreadIdType GetMainId() { return ms_idMainThread; }
+
+        // Release the rest of our time slice letting the other threads run
+    static void Yield();
+
+        // Sleep during the specified period of time in milliseconds
+        //
+        // This is the same as wxMilliSleep().
+    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 = 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 under 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;
+
+    wxThreadKind GetKind() const
+        { return m_isDetached ? wxTHREAD_DETACHED : wxTHREAD_JOINABLE; }
+
+    // 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()!
+    virtual bool TestDestroy();
+
+    // dtor is public, but the detached threads should never be deleted - use
+    // Delete() instead (or leave the thread terminate by itself)
+    virtual ~wxThread();

 
 

-  // Returns the wxThread object which corresponds to the ID.
-  static wxThread *GetThreadFromID(unsigned long id);

 protected:
 protected:

-  // In case, the DIFFER flag is true, enables another thread to kill this one.
-  void 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);
+
+    // entry point for the thread - called by Run() and executes in the context
+    // of this thread.
+    virtual void *Entry() = 0;
+

 private:
 private:

-  // Entry point for the thread.
-  virtual void *Entry() = 0;
+    // no copy ctor/assignment operator
+    wxThread(const wxThread&);
+    wxThread& operator=(const wxThread&);
+
+    // 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() { }
+
+    friend class wxThreadInternal;
+    friend class wxThreadModule;
+
+
+    // the main thread identifier, should be set on startup
+    static wxThreadIdType ms_idMainThread;
+
+    // the (platform-dependent) thread class implementation
+    wxThreadInternal *m_internal;
+
+    // protects access to any methods of wxThreadInternal object
+    wxCriticalSection m_critsect;
+
+    // true if the thread is detached, false if it is joinable
+    bool m_isDetached;
+};
+
+// wxThreadHelperThread class
+// --------------------------
+
+class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread
+{
+public:
+    // constructor only creates the C++ thread object and doesn't create (or
+    // start) the real thread
+    wxThreadHelperThread(wxThreadHelper& owner, wxThreadKind kind)
+        : wxThread(kind), m_owner(owner)
+        { }
+
+protected:
+    // entry point for the thread -- calls Entry() in owner.
+    virtual void *Entry();

 
 private:
 
 private:

-  friend class wxThreadInternal;
+    // the owner of the thread
+    wxThreadHelper& m_owner;

 
 

-  wxThreadInternal *p_internal;
+    // no copy ctor/assignment operator
+    wxThreadHelperThread(const wxThreadHelperThread&);
+    wxThreadHelperThread& operator=(const wxThreadHelperThread&);

 };
 
 };
 

-// ---------------------------------------------------------------------------
-// Global variables
+// ----------------------------------------------------------------------------
+// wxThreadHelper: this class implements the threading logic to run a
+// background task in another object (such as a window).  It is a mix-in: just
+// derive from it to implement a threading background task in your class.
+// ----------------------------------------------------------------------------

 
 

-// GUI mutex handling.
-void WXDLLEXPORT wxMutexGuiEnter();
-void WXDLLEXPORT wxMutexGuiLeave();
+class WXDLLIMPEXP_BASE wxThreadHelper
+{
+private:
+    void KillThread()
+    {
+        // If wxThreadHelperThread is detached and is about to finish, it will
+        // set m_thread to NULL so don't delete it then.
+        // But if KillThread is called before wxThreadHelperThread (in detached mode)
+        // sets it to NULL, then the thread object still exists and can be killed
+        wxCriticalSectionLocker locker(m_critSection);
+
+        if ( m_thread )
+        {
+            m_thread->Kill();
+
+            if ( m_kind == wxTHREAD_JOINABLE )
+              delete m_thread;

 
 

+            m_thread = NULL;
+        }
+    }
+
+public:
+    // constructor only initializes m_thread to NULL
+    wxThreadHelper(wxThreadKind kind = wxTHREAD_JOINABLE)
+        : m_thread(NULL), m_kind(kind) { }
+
+    // destructor deletes m_thread
+    virtual ~wxThreadHelper() { KillThread(); }
+
+#if WXWIN_COMPATIBILITY_2_8
+    wxDEPRECATED( wxThreadError Create(unsigned int stackSize = 0) );
+#endif
+
+    // create a new thread (and optionally set the stack size on platforms that
+    // support/need that), call Run() to start it
+    wxThreadError CreateThread(wxThreadKind kind = wxTHREAD_JOINABLE,
+                               unsigned int stackSize = 0)
+    {
+        KillThread();
+
+        m_kind = kind;
+        m_thread = new wxThreadHelperThread(*this, m_kind);
+
+        return m_thread->Create(stackSize);
+    }
+
+    // entry point for the thread - called by Run() and executes in the context
+    // of this thread.
+    virtual void *Entry() = 0;
+
+    // returns a pointer to the thread which can be used to call Run()
+    wxThread *GetThread() const
+    {
+        wxCriticalSectionLocker locker((wxCriticalSection&)m_critSection);
+
+        wxThread* thread = m_thread;
+
+        return thread;
+    }
+
+protected:
+    wxThread *m_thread;
+    wxThreadKind m_kind;
+    wxCriticalSection m_critSection; // To guard the m_thread variable
+
+    friend class wxThreadHelperThread;
+};
+
+#if WXWIN_COMPATIBILITY_2_8
+inline wxThreadError wxThreadHelper::Create(unsigned int stackSize)
+{ return CreateThread(m_kind, stackSize); }

 #endif
 #endif

+
+// call Entry() in owner, put it down here to avoid circular declarations
+inline void *wxThreadHelperThread::Entry()
+{
+    void * const result = m_owner.Entry();
+
+    wxCriticalSectionLocker locker(m_owner.m_critSection);
+
+    // Detached thread will be deleted after returning, so make sure
+    // wxThreadHelper::GetThread will not return an invalid pointer.
+    // And that wxThreadHelper::KillThread will not try to kill
+    // an already deleted thread
+    if ( m_owner.m_kind == wxTHREAD_DETACHED )
+        m_owner.m_thread = NULL;
+
+    return result;
+}
+
+// ----------------------------------------------------------------------------
+// Automatic initialization
+// ----------------------------------------------------------------------------
+
+// GUI mutex handling.
+void WXDLLIMPEXP_BASE wxMutexGuiEnter();
+void WXDLLIMPEXP_BASE 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)   (cs).Enter()
+#define wxLEAVE_CRIT_SECT(cs)   (cs).Leave()
+#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
+#define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs
+#define wxCRIT_SECT_LOCKER(name, cs)  wxCriticalSectionLocker name(cs)
+
+// function for checking if we're in the main thread which may be used whether
+// wxUSE_THREADS is 0 or 1
+inline bool wxIsMainThread() { return wxThread::IsMain(); }
+
+#else // !wxUSE_THREADS
+
+// no thread support
+inline void wxMutexGuiEnter() { }
+inline void wxMutexGuiLeave() { }
+
+// macros for entering/leaving critical sections which may be used without
+// having to take them inside "#if wxUSE_THREADS"
+// (the implementation uses dummy structs to force semicolon after the macro;
+// also notice that Watcom doesn't like declaring a struct as a member so we
+// need to actually define it in wxCRIT_SECT_DECLARE_MEMBER)
+#define wxENTER_CRIT_SECT(cs)            do {} while (0)
+#define wxLEAVE_CRIT_SECT(cs)            do {} while (0)
+#define wxCRIT_SECT_DECLARE(cs)          struct wxDummyCS##cs
+#define wxCRIT_SECT_DECLARE_MEMBER(cs)   struct wxDummyCSMember##cs { }
+#define wxCRIT_SECT_LOCKER(name, cs)     struct wxDummyCSLocker##name
+
+// if there is only one thread, it is always the main one
+inline bool wxIsMainThread() { return true; }
+
+#endif // wxUSE_THREADS/!wxUSE_THREADS
+
+// mark part of code as being a critical section: this macro declares a
+// critical section with the given name and enters it immediately and leaves
+// it at the end of the current scope
+//
+// example:
+//
+//      int Count()
+//      {
+//          static int s_counter = 0;
+//
+//          wxCRITICAL_SECTION(counter);
+//
+//          return ++s_counter;
+//      }
+//
+// this function is MT-safe in presence of the threads but there is no
+// overhead when the library is compiled without threads
+#define wxCRITICAL_SECTION(name) \
+    wxCRIT_SECT_DECLARE(s_cs##name);  \
+    wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name)
+
+// automatically lock GUI mutex in ctor and unlock it in dtor
+class WXDLLIMPEXP_BASE wxMutexGuiLocker
+{
+public:
+    wxMutexGuiLocker() { wxMutexGuiEnter(); }
+   ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
+};
+
+// -----------------------------------------------------------------------------
+// implementation only until the end of file
+// -----------------------------------------------------------------------------
+
+#if wxUSE_THREADS
+
+#if defined(__WXMSW__) || defined(__OS2__) || defined(__EMX__)
+    // 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 WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter();
+
+    // returns true if the main thread has GUI lock
+    extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread();
+
+    // wakes up the main thread if it's sleeping inside ::GetMessage()
+    extern void WXDLLIMPEXP_BASE wxWakeUpMainThread();
+
+    // return true if the main thread is waiting for some other to terminate:
+    // wxApp then should block all "dangerous" messages
+    extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread();
+#endif // MSW, OS/2
+
+#endif // wxUSE_THREADS
+
+#endif // _WX_THREAD_H_