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1 /////////////////////////////////////////////////////////////////////////////
2 // Name: wx/thread.h
3 // Purpose: Thread API
4 // Author: Guilhem Lavaux
5 // Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads
6 // package from Olivetti & Oracle Research Laboratory)
7 // Created: 04/13/98
8 // RCS-ID: $Id$
9 // Copyright: (c) Guilhem Lavaux
10 // Licence: wxWindows licence
11 /////////////////////////////////////////////////////////////////////////////
12
13 #ifndef _WX_THREAD_H_
14 #define _WX_THREAD_H_
15
16 // ----------------------------------------------------------------------------
17 // headers
18 // ----------------------------------------------------------------------------
19
20 // get the value of wxUSE_THREADS configuration flag
21 #include "wx/defs.h"
22
23 #if wxUSE_THREADS
24
25 // ----------------------------------------------------------------------------
26 // constants
27 // ----------------------------------------------------------------------------
28
29 enum wxMutexError
30 {
31 wxMUTEX_NO_ERROR = 0, // operation completed successfully
32 wxMUTEX_INVALID, // mutex hasn't been initialized
33 wxMUTEX_DEAD_LOCK, // mutex is already locked by the calling thread
34 wxMUTEX_BUSY, // mutex is already locked by another thread
35 wxMUTEX_UNLOCKED, // attempt to unlock a mutex which is not locked
36 wxMUTEX_TIMEOUT, // LockTimeout() has timed out
37 wxMUTEX_MISC_ERROR // any other error
38 };
39
40 enum wxCondError
41 {
42 wxCOND_NO_ERROR = 0,
43 wxCOND_INVALID,
44 wxCOND_TIMEOUT, // WaitTimeout() has timed out
45 wxCOND_MISC_ERROR
46 };
47
48 enum wxSemaError
49 {
50 wxSEMA_NO_ERROR = 0,
51 wxSEMA_INVALID, // semaphore hasn't been initialized successfully
52 wxSEMA_BUSY, // returned by TryWait() if Wait() would block
53 wxSEMA_TIMEOUT, // returned by WaitTimeout()
54 wxSEMA_OVERFLOW, // Post() would increase counter past the max
55 wxSEMA_MISC_ERROR
56 };
57
58 enum wxThreadError
59 {
60 wxTHREAD_NO_ERROR = 0, // No error
61 wxTHREAD_NO_RESOURCE, // No resource left to create a new thread
62 wxTHREAD_RUNNING, // The thread is already running
63 wxTHREAD_NOT_RUNNING, // The thread isn't running
64 wxTHREAD_KILLED, // Thread we waited for had to be killed
65 wxTHREAD_MISC_ERROR // Some other error
66 };
67
68 enum wxThreadKind
69 {
70 wxTHREAD_DETACHED,
71 wxTHREAD_JOINABLE
72 };
73
74 // defines the interval of priority
75 enum
76 {
77 WXTHREAD_MIN_PRIORITY = 0u,
78 WXTHREAD_DEFAULT_PRIORITY = 50u,
79 WXTHREAD_MAX_PRIORITY = 100u
80 };
81
82 // There are 2 types of mutexes: normal mutexes and recursive ones. The attempt
83 // to lock a normal mutex by a thread which already owns it results in
84 // undefined behaviour (it always works under Windows, it will almost always
85 // result in a deadlock under Unix). Locking a recursive mutex in such
86 // situation always succeeds and it must be unlocked as many times as it has
87 // been locked.
88 //
89 // However recursive mutexes have several important drawbacks: first, in the
90 // POSIX implementation, they're less efficient. Second, and more importantly,
91 // they CAN NOT BE USED WITH CONDITION VARIABLES under Unix! Using them with
92 // wxCondition will work under Windows and some Unices (notably Linux) but will
93 // deadlock under other Unix versions (e.g. Solaris). As it might be difficult
94 // to ensure that a recursive mutex is not used with wxCondition, it is a good
95 // idea to avoid using recursive mutexes at all. Also, the last problem with
96 // them is that some (older) Unix versions don't support this at all -- which
97 // results in a configure warning when building and a deadlock when using them.
98 enum wxMutexType
99 {
100 // normal mutex: try to always use this one
101 wxMUTEX_DEFAULT,
102
103 // recursive mutex: don't use these ones with wxCondition
104 wxMUTEX_RECURSIVE
105 };
106
107 // forward declarations
108 class WXDLLIMPEXP_FWD_BASE wxThreadHelper;
109 class WXDLLIMPEXP_FWD_BASE wxConditionInternal;
110 class WXDLLIMPEXP_FWD_BASE wxMutexInternal;
111 class WXDLLIMPEXP_FWD_BASE wxSemaphoreInternal;
112 class WXDLLIMPEXP_FWD_BASE wxThreadInternal;
113
114 // ----------------------------------------------------------------------------
115 // A mutex object is a synchronization object whose state is set to signaled
116 // when it is not owned by any thread, and nonsignaled when it is owned. Its
117 // name comes from its usefulness in coordinating mutually-exclusive access to
118 // a shared resource. Only one thread at a time can own a mutex object.
119 // ----------------------------------------------------------------------------
120
121 // you should consider wxMutexLocker whenever possible instead of directly
122 // working with wxMutex class - it is safer
123 class WXDLLIMPEXP_BASE wxMutex
124 {
125 public:
126 // constructor & destructor
127 // ------------------------
128
129 // create either default (always safe) or recursive mutex
130 wxMutex(wxMutexType mutexType = wxMUTEX_DEFAULT);
131
132 // destroys the mutex kernel object
133 ~wxMutex();
134
135 // test if the mutex has been created successfully
136 bool IsOk() const;
137
138 // mutex operations
139 // ----------------
140
141 // Lock the mutex, blocking on it until it is unlocked by the other thread.
142 // The result of locking a mutex already locked by the current thread
143 // depend on the mutex type.
144 //
145 // The caller must call Unlock() later if Lock() returned wxMUTEX_NO_ERROR.
146 wxMutexError Lock();
147
148 // Same as Lock() but return wxMUTEX_TIMEOUT if the mutex can't be locked
149 // during the given number of milliseconds
150 wxMutexError LockTimeout(unsigned long ms);
151
152 // Try to lock the mutex: if it is currently locked, return immediately
153 // with an error. Otherwise the caller must call Unlock().
154 wxMutexError TryLock();
155
156 // Unlock the mutex. It is an error to unlock an already unlocked mutex
157 wxMutexError Unlock();
158
159 protected:
160 wxMutexInternal *m_internal;
161
162 friend class wxConditionInternal;
163
164 DECLARE_NO_COPY_CLASS(wxMutex)
165 };
166
167 // a helper class which locks the mutex in the ctor and unlocks it in the dtor:
168 // this ensures that mutex is always unlocked, even if the function returns or
169 // throws an exception before it reaches the end
170 class WXDLLIMPEXP_BASE wxMutexLocker
171 {
172 public:
173 // lock the mutex in the ctor
174 wxMutexLocker(wxMutex& mutex)
175 : m_isOk(false), m_mutex(mutex)
176 { m_isOk = ( m_mutex.Lock() == wxMUTEX_NO_ERROR ); }
177
178 // returns true if mutex was successfully locked in ctor
179 bool IsOk() const
180 { return m_isOk; }
181
182 // unlock the mutex in dtor
183 ~wxMutexLocker()
184 { if ( IsOk() ) m_mutex.Unlock(); }
185
186 private:
187 // no assignment operator nor copy ctor
188 wxMutexLocker(const wxMutexLocker&);
189 wxMutexLocker& operator=(const wxMutexLocker&);
190
191 bool m_isOk;
192 wxMutex& m_mutex;
193 };
194
195 // ----------------------------------------------------------------------------
196 // Critical section: this is the same as mutex but is only visible to the
197 // threads of the same process. For the platforms which don't have native
198 // support for critical sections, they're implemented entirely in terms of
199 // mutexes.
200 //
201 // NB: wxCriticalSection object does not allocate any memory in its ctor
202 // which makes it possible to have static globals of this class
203 // ----------------------------------------------------------------------------
204
205 // in order to avoid any overhead under platforms where critical sections are
206 // just mutexes make all wxCriticalSection class functions inline
207 #if !defined(__WXMSW__)
208 #define wxCRITSECT_IS_MUTEX 1
209
210 #define wxCRITSECT_INLINE inline
211 #else // MSW
212 #define wxCRITSECT_IS_MUTEX 0
213
214 #define wxCRITSECT_INLINE
215 #endif // MSW/!MSW
216
217 // you should consider wxCriticalSectionLocker whenever possible instead of
218 // directly working with wxCriticalSection class - it is safer
219 class WXDLLIMPEXP_BASE wxCriticalSection
220 {
221 public:
222 // ctor & dtor
223 wxCRITSECT_INLINE wxCriticalSection();
224 wxCRITSECT_INLINE ~wxCriticalSection();
225
226 // enter the section (the same as locking a mutex)
227 wxCRITSECT_INLINE void Enter();
228
229 // leave the critical section (same as unlocking a mutex)
230 wxCRITSECT_INLINE void Leave();
231
232 private:
233 #if wxCRITSECT_IS_MUTEX
234 wxMutex m_mutex;
235 #elif defined(__WXMSW__)
236 // we can't allocate any memory in the ctor, so use placement new -
237 // unfortunately, we have to hardcode the sizeof() here because we can't
238 // include windows.h from this public header and we also have to use the
239 // union to force the correct (i.e. maximal) alignment
240 //
241 // if CRITICAL_SECTION size changes in Windows, you'll get an assert from
242 // thread.cpp and will need to increase the buffer size
243 //
244 // finally, we need this typedef instead of declaring m_buffer directly
245 // because otherwise the assert mentioned above wouldn't compile with some
246 // compilers (notably CodeWarrior 8)
247 #ifdef __WIN64__
248 typedef char wxCritSectBuffer[40];
249 #else // __WIN32__
250 typedef char wxCritSectBuffer[24];
251 #endif
252 union
253 {
254 unsigned long m_dummy1;
255 void *m_dummy2;
256
257 wxCritSectBuffer m_buffer;
258 };
259 #endif // Unix&OS2/Win32
260
261 DECLARE_NO_COPY_CLASS(wxCriticalSection)
262 };
263
264 #if wxCRITSECT_IS_MUTEX
265 // implement wxCriticalSection using mutexes
266 inline wxCriticalSection::wxCriticalSection() { }
267 inline wxCriticalSection::~wxCriticalSection() { }
268
269 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
270 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
271 #endif // wxCRITSECT_IS_MUTEX
272
273 #undef wxCRITSECT_INLINE
274 #undef wxCRITSECT_IS_MUTEX
275
276 // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
277 // to mutexes
278 class WXDLLIMPEXP_BASE wxCriticalSectionLocker
279 {
280 public:
281 wxCriticalSectionLocker(wxCriticalSection& cs)
282 : m_critsect(cs)
283 {
284 m_critsect.Enter();
285 }
286
287 ~wxCriticalSectionLocker()
288 {
289 m_critsect.Leave();
290 }
291
292 private:
293 wxCriticalSection& m_critsect;
294
295 DECLARE_NO_COPY_CLASS(wxCriticalSectionLocker)
296 };
297
298 // ----------------------------------------------------------------------------
299 // wxCondition models a POSIX condition variable which allows one (or more)
300 // thread(s) to wait until some condition is fulfilled
301 // ----------------------------------------------------------------------------
302
303 class WXDLLIMPEXP_BASE wxCondition
304 {
305 public:
306 // Each wxCondition object is associated with a (single) wxMutex object.
307 // The mutex object MUST be locked before calling Wait()
308 wxCondition(wxMutex& mutex);
309
310 // dtor is not virtual, don't use this class polymorphically
311 ~wxCondition();
312
313 // return true if the condition has been created successfully
314 bool IsOk() const;
315
316 // NB: the associated mutex MUST be locked beforehand by the calling thread
317 //
318 // it atomically releases the lock on the associated mutex
319 // and starts waiting to be woken up by a Signal()/Broadcast()
320 // once its signaled, then it will wait until it can reacquire
321 // the lock on the associated mutex object, before returning.
322 wxCondError Wait();
323
324 // exactly as Wait() except that it may also return if the specified
325 // timeout elapses even if the condition hasn't been signalled: in this
326 // case, the return value is false, otherwise (i.e. in case of a normal
327 // return) it is true
328 //
329 // the timeout parameter specifies an interval that needs to be waited for
330 // in milliseconds
331 wxCondError WaitTimeout(unsigned long milliseconds);
332
333 // NB: the associated mutex may or may not be locked by the calling thread
334 //
335 // this method unblocks one thread if any are blocking on the condition.
336 // if no thread is blocking in Wait(), then the signal is NOT remembered
337 // The thread which was blocking on Wait() will then reacquire the lock
338 // on the associated mutex object before returning
339 wxCondError Signal();
340
341 // NB: the associated mutex may or may not be locked by the calling thread
342 //
343 // this method unblocks all threads if any are blocking on the condition.
344 // if no thread is blocking in Wait(), then the signal is NOT remembered
345 // The threads which were blocking on Wait() will then reacquire the lock
346 // on the associated mutex object before returning.
347 wxCondError Broadcast();
348
349
350 #if WXWIN_COMPATIBILITY_2_6
351 // deprecated version, don't use
352 wxDEPRECATED( bool Wait(unsigned long milliseconds) );
353 #endif // WXWIN_COMPATIBILITY_2_6
354
355 private:
356 wxConditionInternal *m_internal;
357
358 DECLARE_NO_COPY_CLASS(wxCondition)
359 };
360
361 #if WXWIN_COMPATIBILITY_2_6
362 inline bool wxCondition::Wait(unsigned long milliseconds)
363 { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; }
364 #endif // WXWIN_COMPATIBILITY_2_6
365
366 // ----------------------------------------------------------------------------
367 // wxSemaphore: a counter limiting the number of threads concurrently accessing
368 // a shared resource
369 // ----------------------------------------------------------------------------
370
371 class WXDLLIMPEXP_BASE wxSemaphore
372 {
373 public:
374 // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
375 // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
376 wxSemaphore( int initialcount = 0, int maxcount = 0 );
377
378 // dtor is not virtual, don't use this class polymorphically
379 ~wxSemaphore();
380
381 // return true if the semaphore has been created successfully
382 bool IsOk() const;
383
384 // wait indefinitely, until the semaphore count goes beyond 0
385 // and then decrement it and return (this method might have been called
386 // Acquire())
387 wxSemaError Wait();
388
389 // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if
390 // successful and wxSEMA_BUSY if the count is currently zero
391 wxSemaError TryWait();
392
393 // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the
394 // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has elapsed
395 wxSemaError WaitTimeout(unsigned long milliseconds);
396
397 // increments the semaphore count and signals one of the waiting threads
398 wxSemaError Post();
399
400 private:
401 wxSemaphoreInternal *m_internal;
402
403 DECLARE_NO_COPY_CLASS(wxSemaphore)
404 };
405
406 // ----------------------------------------------------------------------------
407 // wxThread: class encapsulating a thread of execution
408 // ----------------------------------------------------------------------------
409
410 // there are two different kinds of threads: joinable and detached (default)
411 // ones. Only joinable threads can return a return code and only detached
412 // threads auto-delete themselves - the user should delete the joinable
413 // threads manually.
414
415 // NB: in the function descriptions the words "this thread" mean the thread
416 // created by the wxThread object while "main thread" is the thread created
417 // during the process initialization (a.k.a. the GUI thread)
418
419 // On VMS thread pointers are 64 bits (also needed for other systems???
420 #ifdef __VMS
421 typedef unsigned long long wxThreadIdType;
422 #else
423 typedef unsigned long wxThreadIdType;
424 #endif
425
426 class WXDLLIMPEXP_BASE wxThread
427 {
428 public:
429 // the return type for the thread function
430 typedef void *ExitCode;
431
432 // static functions
433 // Returns the wxThread object for the calling thread. NULL is returned
434 // if the caller is the main thread (but it's recommended to use
435 // IsMain() and only call This() for threads other than the main one
436 // because NULL is also returned on error). If the thread wasn't
437 // created with wxThread class, the returned value is undefined.
438 static wxThread *This();
439
440 // Returns true if current thread is the main thread.
441 static bool IsMain();
442
443 // Release the rest of our time slice letting the other threads run
444 static void Yield();
445
446 // Sleep during the specified period of time in milliseconds
447 //
448 // This is the same as wxMilliSleep().
449 static void Sleep(unsigned long milliseconds);
450
451 // get the number of system CPUs - useful with SetConcurrency()
452 // (the "best" value for it is usually number of CPUs + 1)
453 //
454 // Returns -1 if unknown, number of CPUs otherwise
455 static int GetCPUCount();
456
457 // Get the platform specific thread ID and return as a long. This
458 // can be used to uniquely identify threads, even if they are not
459 // wxThreads. This is used by wxPython.
460 static wxThreadIdType GetCurrentId();
461
462 // sets the concurrency level: this is, roughly, the number of threads
463 // the system tries to schedule to run in parallel. 0 means the
464 // default value (usually acceptable, but may not yield the best
465 // performance for this process)
466 //
467 // Returns true on success, false otherwise (if not implemented, for
468 // example)
469 static bool SetConcurrency(size_t level);
470
471 // constructor only creates the C++ thread object and doesn't create (or
472 // start) the real thread
473 wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
474
475 // functions that change the thread state: all these can only be called
476 // from _another_ thread (typically the thread that created this one, e.g.
477 // the main thread), not from the thread itself
478
479 // create a new thread and optionally set the stack size on
480 // platforms that support that - call Run() to start it
481 // (special cased for watcom which won't accept 0 default)
482
483 wxThreadError Create(unsigned int stackSize = 0);
484
485 // starts execution of the thread - from the moment Run() is called
486 // the execution of wxThread::Entry() may start at any moment, caller
487 // shouldn't suppose that it starts after (or before) Run() returns.
488 wxThreadError Run();
489
490 // stops the thread if it's running and deletes the wxThread object if
491 // this is a detached thread freeing its memory - otherwise (for
492 // joinable threads) you still need to delete wxThread object
493 // yourself.
494 //
495 // this function only works if the thread calls TestDestroy()
496 // periodically - the thread will only be deleted the next time it
497 // does it!
498 //
499 // will fill the rc pointer with the thread exit code if it's !NULL
500 wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
501
502 // waits for a joinable thread to finish and returns its exit code
503 //
504 // Returns (ExitCode)-1 on error (for example, if the thread is not
505 // joinable)
506 ExitCode Wait();
507
508 // kills the thread without giving it any chance to clean up - should
509 // not be used under normal circumstances, use Delete() instead.
510 // It is a dangerous function that should only be used in the most
511 // extreme cases!
512 //
513 // The wxThread object is deleted by Kill() if the thread is
514 // detachable, but you still have to delete it manually for joinable
515 // threads.
516 wxThreadError Kill();
517
518 // pause a running thread: as Delete(), this only works if the thread
519 // calls TestDestroy() regularly
520 wxThreadError Pause();
521
522 // resume a paused thread
523 wxThreadError Resume();
524
525 // priority
526 // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
527 //
528 // NB: the priority can only be set before the thread is created
529 void SetPriority(unsigned int prio);
530
531 // Get the current priority.
532 unsigned int GetPriority() const;
533
534 // thread status inquiries
535 // Returns true if the thread is alive: i.e. running or suspended
536 bool IsAlive() const;
537 // Returns true if the thread is running (not paused, not killed).
538 bool IsRunning() const;
539 // Returns true if the thread is suspended
540 bool IsPaused() const;
541
542 // is the thread of detached kind?
543 bool IsDetached() const { return m_isDetached; }
544
545 // Get the thread ID - a platform dependent number which uniquely
546 // identifies a thread inside a process
547 wxThreadIdType GetId() const;
548
549 // called when the thread exits - in the context of this thread
550 //
551 // NB: this function will not be called if the thread is Kill()ed
552 virtual void OnExit() { }
553
554 // Returns true if the thread was asked to terminate: this function should
555 // be called by the thread from time to time, otherwise the main thread
556 // will be left forever in Delete()!
557 virtual bool TestDestroy();
558
559 // dtor is public, but the detached threads should never be deleted - use
560 // Delete() instead (or leave the thread terminate by itself)
561 virtual ~wxThread();
562
563 protected:
564 // exits from the current thread - can be called only from this thread
565 void Exit(ExitCode exitcode = 0);
566
567 // entry point for the thread - called by Run() and executes in the context
568 // of this thread.
569 virtual void *Entry() = 0;
570
571 private:
572 // no copy ctor/assignment operator
573 wxThread(const wxThread&);
574 wxThread& operator=(const wxThread&);
575
576 friend class wxThreadInternal;
577
578 // the (platform-dependent) thread class implementation
579 wxThreadInternal *m_internal;
580
581 // protects access to any methods of wxThreadInternal object
582 wxCriticalSection m_critsect;
583
584 // true if the thread is detached, false if it is joinable
585 bool m_isDetached;
586 };
587
588 // wxThreadHelperThread class
589 // --------------------------
590
591 class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread
592 {
593 public:
594 // constructor only creates the C++ thread object and doesn't create (or
595 // start) the real thread
596 wxThreadHelperThread(wxThreadHelper& owner, wxThreadKind kind)
597 : wxThread(kind), m_owner(owner)
598 { }
599
600 protected:
601 // entry point for the thread -- calls Entry() in owner.
602 virtual void *Entry();
603
604 private:
605 // the owner of the thread
606 wxThreadHelper& m_owner;
607
608 // no copy ctor/assignment operator
609 wxThreadHelperThread(const wxThreadHelperThread&);
610 wxThreadHelperThread& operator=(const wxThreadHelperThread&);
611 };
612
613 // ----------------------------------------------------------------------------
614 // wxThreadHelper: this class implements the threading logic to run a
615 // background task in another object (such as a window). It is a mix-in: just
616 // derive from it to implement a threading background task in your class.
617 // ----------------------------------------------------------------------------
618
619 class WXDLLIMPEXP_BASE wxThreadHelper
620 {
621 private:
622 void KillThread()
623 {
624 // If detached thread is about to finish, it will set
625 // m_thread to NULL so don't delete it then
626 // But if KillThread is called before detached thread
627 // sets it to NULL, then the thread object still
628 // exists and can be killed
629 wxCriticalSectionLocker locker(m_critSection);
630
631 if ( m_thread )
632 {
633 m_thread->Kill();
634
635 if ( m_kind == wxTHREAD_JOINABLE )
636 delete m_thread;
637
638 m_thread = NULL;
639 }
640 }
641
642 public:
643 // constructor only initializes m_thread to NULL
644 wxThreadHelper(wxThreadKind kind = wxTHREAD_JOINABLE)
645 : m_thread(NULL), m_kind(kind) { }
646
647 // destructor deletes m_thread
648 virtual ~wxThreadHelper() { KillThread(); }
649
650 // create a new thread (and optionally set the stack size on platforms that
651 // support/need that), call Run() to start it
652 wxThreadError Create(unsigned int stackSize = 0)
653 {
654 KillThread();
655
656 m_thread = new wxThreadHelperThread(*this, m_kind);
657
658 return m_thread->Create(stackSize);
659 }
660
661 // entry point for the thread - called by Run() and executes in the context
662 // of this thread.
663 virtual void *Entry() = 0;
664
665 // returns a pointer to the thread which can be used to call Run()
666 wxThread *GetThread() const
667 {
668 wxCriticalSectionLocker locker((wxCriticalSection&)m_critSection);
669
670 wxThread* thread = m_thread;
671
672 return thread;
673 }
674
675 protected:
676 wxThread *m_thread;
677 wxThreadKind m_kind;
678 wxCriticalSection m_critSection; // To guard the m_thread variable
679
680 friend class wxThreadHelperThread;
681 };
682
683 // call Entry() in owner, put it down here to avoid circular declarations
684 inline void *wxThreadHelperThread::Entry()
685 {
686 void * const result = m_owner.Entry();
687
688 wxCriticalSectionLocker locker(m_owner.m_critSection);
689
690 // Detached thread will be deleted after returning, so make sure
691 // wxThreadHelper::GetThread will not return an invalid pointer.
692 // And that wxThreadHelper::KillThread will not try to kill
693 // an already deleted thread
694 if ( m_owner.m_kind == wxTHREAD_DETACHED )
695 m_owner.m_thread = NULL;
696
697 return result;
698 }
699
700 // ----------------------------------------------------------------------------
701 // Automatic initialization
702 // ----------------------------------------------------------------------------
703
704 // GUI mutex handling.
705 void WXDLLIMPEXP_BASE wxMutexGuiEnter();
706 void WXDLLIMPEXP_BASE wxMutexGuiLeave();
707
708 // macros for entering/leaving critical sections which may be used without
709 // having to take them inside "#if wxUSE_THREADS"
710 #define wxENTER_CRIT_SECT(cs) (cs).Enter()
711 #define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
712 #define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
713 #define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs
714 #define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
715
716 // function for checking if we're in the main thread which may be used whether
717 // wxUSE_THREADS is 0 or 1
718 inline bool wxIsMainThread() { return wxThread::IsMain(); }
719
720 #else // !wxUSE_THREADS
721
722 // no thread support
723 inline void wxMutexGuiEnter() { }
724 inline void wxMutexGuiLeave() { }
725
726 // macros for entering/leaving critical sections which may be used without
727 // having to take them inside "#if wxUSE_THREADS"
728 // (the implementation uses dummy structs to force semicolon after the macro)
729 #define wxENTER_CRIT_SECT(cs) do {} while (0)
730 #define wxLEAVE_CRIT_SECT(cs) do {} while (0)
731 #define wxCRIT_SECT_DECLARE(cs) struct wxDummyCS##cs
732 #define wxCRIT_SECT_DECLARE_MEMBER(cs) struct wxDummyCSMember##cs
733 #define wxCRIT_SECT_LOCKER(name, cs) struct wxDummyCSLocker##name
734
735 // if there is only one thread, it is always the main one
736 inline bool wxIsMainThread() { return true; }
737
738 #endif // wxUSE_THREADS/!wxUSE_THREADS
739
740 // mark part of code as being a critical section: this macro declares a
741 // critical section with the given name and enters it immediately and leaves
742 // it at the end of the current scope
743 //
744 // example:
745 //
746 // int Count()
747 // {
748 // static int s_counter = 0;
749 //
750 // wxCRITICAL_SECTION(counter);
751 //
752 // return ++s_counter;
753 // }
754 //
755 // this function is MT-safe in presence of the threads but there is no
756 // overhead when the library is compiled without threads
757 #define wxCRITICAL_SECTION(name) \
758 wxCRIT_SECT_DECLARE(s_cs##name); \
759 wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name)
760
761 // automatically lock GUI mutex in ctor and unlock it in dtor
762 class WXDLLIMPEXP_BASE wxMutexGuiLocker
763 {
764 public:
765 wxMutexGuiLocker() { wxMutexGuiEnter(); }
766 ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
767 };
768
769 // -----------------------------------------------------------------------------
770 // implementation only until the end of file
771 // -----------------------------------------------------------------------------
772
773 #if wxUSE_THREADS
774
775 #if defined(__WXMSW__) || defined(__OS2__) || defined(__EMX__)
776 // unlock GUI if there are threads waiting for and lock it back when
777 // there are no more of them - should be called periodically by the main
778 // thread
779 extern void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter();
780
781 // returns true if the main thread has GUI lock
782 extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread();
783
784 // wakes up the main thread if it's sleeping inside ::GetMessage()
785 extern void WXDLLIMPEXP_BASE wxWakeUpMainThread();
786
787 // return true if the main thread is waiting for some other to terminate:
788 // wxApp then should block all "dangerous" messages
789 extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread();
790 #endif // MSW, OS/2
791
792 #endif // wxUSE_THREADS
793
794 #endif // _WX_THREAD_H_