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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__) && !defined(__WXMAC__)
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 #elif defined(__WXMAC__)
260 void *m_critRegion ;
261 #endif // Unix&OS2/Win32
262
263 DECLARE_NO_COPY_CLASS(wxCriticalSection)
264 };
265
266 #if wxCRITSECT_IS_MUTEX
267 // implement wxCriticalSection using mutexes
268 inline wxCriticalSection::wxCriticalSection() { }
269 inline wxCriticalSection::~wxCriticalSection() { }
270
271 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
272 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
273 #endif // wxCRITSECT_IS_MUTEX
274
275 #undef wxCRITSECT_INLINE
276 #undef wxCRITSECT_IS_MUTEX
277
278 // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
279 // to mutexes
280 class WXDLLIMPEXP_BASE wxCriticalSectionLocker
281 {
282 public:
283 wxCriticalSectionLocker(wxCriticalSection& cs)
284 : m_critsect(cs)
285 {
286 m_critsect.Enter();
287 }
288
289 ~wxCriticalSectionLocker()
290 {
291 m_critsect.Leave();
292 }
293
294 private:
295 wxCriticalSection& m_critsect;
296
297 DECLARE_NO_COPY_CLASS(wxCriticalSectionLocker)
298 };
299
300 // ----------------------------------------------------------------------------
301 // wxCondition models a POSIX condition variable which allows one (or more)
302 // thread(s) to wait until some condition is fulfilled
303 // ----------------------------------------------------------------------------
304
305 class WXDLLIMPEXP_BASE wxCondition
306 {
307 public:
308 // Each wxCondition object is associated with a (single) wxMutex object.
309 // The mutex object MUST be locked before calling Wait()
310 wxCondition(wxMutex& mutex);
311
312 // dtor is not virtual, don't use this class polymorphically
313 ~wxCondition();
314
315 // return true if the condition has been created successfully
316 bool IsOk() const;
317
318 // NB: the associated mutex MUST be locked beforehand by the calling thread
319 //
320 // it atomically releases the lock on the associated mutex
321 // and starts waiting to be woken up by a Signal()/Broadcast()
322 // once its signaled, then it will wait until it can reacquire
323 // the lock on the associated mutex object, before returning.
324 wxCondError Wait();
325
326 // exactly as Wait() except that it may also return if the specified
327 // timeout elapses even if the condition hasn't been signalled: in this
328 // case, the return value is false, otherwise (i.e. in case of a normal
329 // return) it is true
330 //
331 // the timeout parameter specifies an interval that needs to be waited for
332 // in milliseconds
333 wxCondError WaitTimeout(unsigned long milliseconds);
334
335 // NB: the associated mutex may or may not be locked by the calling thread
336 //
337 // this method unblocks one thread if any are blocking on the condition.
338 // if no thread is blocking in Wait(), then the signal is NOT remembered
339 // The thread which was blocking on Wait() will then reacquire the lock
340 // on the associated mutex object before returning
341 wxCondError Signal();
342
343 // NB: the associated mutex may or may not be locked by the calling thread
344 //
345 // this method unblocks all threads if any are blocking on the condition.
346 // if no thread is blocking in Wait(), then the signal is NOT remembered
347 // The threads which were blocking on Wait() will then reacquire the lock
348 // on the associated mutex object before returning.
349 wxCondError Broadcast();
350
351
352 #if WXWIN_COMPATIBILITY_2_6
353 // deprecated version, don't use
354 wxDEPRECATED( bool Wait(unsigned long milliseconds) );
355 #endif // WXWIN_COMPATIBILITY_2_6
356
357 private:
358 wxConditionInternal *m_internal;
359
360 DECLARE_NO_COPY_CLASS(wxCondition)
361 };
362
363 #if WXWIN_COMPATIBILITY_2_6
364 inline bool wxCondition::Wait(unsigned long milliseconds)
365 { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; }
366 #endif // WXWIN_COMPATIBILITY_2_6
367
368 // ----------------------------------------------------------------------------
369 // wxSemaphore: a counter limiting the number of threads concurrently accessing
370 // a shared resource
371 // ----------------------------------------------------------------------------
372
373 class WXDLLIMPEXP_BASE wxSemaphore
374 {
375 public:
376 // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
377 // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
378 wxSemaphore( int initialcount = 0, int maxcount = 0 );
379
380 // dtor is not virtual, don't use this class polymorphically
381 ~wxSemaphore();
382
383 // return true if the semaphore has been created successfully
384 bool IsOk() const;
385
386 // wait indefinitely, until the semaphore count goes beyond 0
387 // and then decrement it and return (this method might have been called
388 // Acquire())
389 wxSemaError Wait();
390
391 // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if
392 // successful and wxSEMA_BUSY if the count is currently zero
393 wxSemaError TryWait();
394
395 // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the
396 // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has elapsed
397 wxSemaError WaitTimeout(unsigned long milliseconds);
398
399 // increments the semaphore count and signals one of the waiting threads
400 wxSemaError Post();
401
402 private:
403 wxSemaphoreInternal *m_internal;
404
405 DECLARE_NO_COPY_CLASS(wxSemaphore)
406 };
407
408 // ----------------------------------------------------------------------------
409 // wxThread: class encapsulating a thread of execution
410 // ----------------------------------------------------------------------------
411
412 // there are two different kinds of threads: joinable and detached (default)
413 // ones. Only joinable threads can return a return code and only detached
414 // threads auto-delete themselves - the user should delete the joinable
415 // threads manually.
416
417 // NB: in the function descriptions the words "this thread" mean the thread
418 // created by the wxThread object while "main thread" is the thread created
419 // during the process initialization (a.k.a. the GUI thread)
420
421 // On VMS thread pointers are 64 bits (also needed for other systems???
422 #ifdef __VMS
423 typedef unsigned long long wxThreadIdType;
424 #else
425 typedef unsigned long wxThreadIdType;
426 #endif
427
428 class WXDLLIMPEXP_BASE wxThread
429 {
430 public:
431 // the return type for the thread function
432 typedef void *ExitCode;
433
434 // static functions
435 // Returns the wxThread object for the calling thread. NULL is returned
436 // if the caller is the main thread (but it's recommended to use
437 // IsMain() and only call This() for threads other than the main one
438 // because NULL is also returned on error). If the thread wasn't
439 // created with wxThread class, the returned value is undefined.
440 static wxThread *This();
441
442 // Returns true if current thread is the main thread.
443 static bool IsMain();
444
445 // Release the rest of our time slice letting the other threads run
446 static void Yield();
447
448 // Sleep during the specified period of time in milliseconds
449 //
450 // This is the same as wxMilliSleep().
451 static void Sleep(unsigned long milliseconds);
452
453 // get the number of system CPUs - useful with SetConcurrency()
454 // (the "best" value for it is usually number of CPUs + 1)
455 //
456 // Returns -1 if unknown, number of CPUs otherwise
457 static int GetCPUCount();
458
459 // Get the platform specific thread ID and return as a long. This
460 // can be used to uniquely identify threads, even if they are not
461 // wxThreads. This is used by wxPython.
462 static wxThreadIdType GetCurrentId();
463
464 // sets the concurrency level: this is, roughly, the number of threads
465 // the system tries to schedule to run in parallel. 0 means the
466 // default value (usually acceptable, but may not yield the best
467 // performance for this process)
468 //
469 // Returns true on success, false otherwise (if not implemented, for
470 // example)
471 static bool SetConcurrency(size_t level);
472
473 // constructor only creates the C++ thread object and doesn't create (or
474 // start) the real thread
475 wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
476
477 // functions that change the thread state: all these can only be called
478 // from _another_ thread (typically the thread that created this one, e.g.
479 // the main thread), not from the thread itself
480
481 // create a new thread and optionally set the stack size on
482 // platforms that support that - call Run() to start it
483 // (special cased for watcom which won't accept 0 default)
484
485 wxThreadError Create(unsigned int stackSize = 0);
486
487 // starts execution of the thread - from the moment Run() is called
488 // the execution of wxThread::Entry() may start at any moment, caller
489 // shouldn't suppose that it starts after (or before) Run() returns.
490 wxThreadError Run();
491
492 // stops the thread if it's running and deletes the wxThread object if
493 // this is a detached thread freeing its memory - otherwise (for
494 // joinable threads) you still need to delete wxThread object
495 // yourself.
496 //
497 // this function only works if the thread calls TestDestroy()
498 // periodically - the thread will only be deleted the next time it
499 // does it!
500 //
501 // will fill the rc pointer with the thread exit code if it's !NULL
502 wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
503
504 // waits for a joinable thread to finish and returns its exit code
505 //
506 // Returns (ExitCode)-1 on error (for example, if the thread is not
507 // joinable)
508 ExitCode Wait();
509
510 // kills the thread without giving it any chance to clean up - should
511 // not be used under normal circumstances, use Delete() instead.
512 // It is a dangerous function that should only be used in the most
513 // extreme cases!
514 //
515 // The wxThread object is deleted by Kill() if the thread is
516 // detachable, but you still have to delete it manually for joinable
517 // threads.
518 wxThreadError Kill();
519
520 // pause a running thread: as Delete(), this only works if the thread
521 // calls TestDestroy() regularly
522 wxThreadError Pause();
523
524 // resume a paused thread
525 wxThreadError Resume();
526
527 // priority
528 // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
529 //
530 // NB: the priority can only be set before the thread is created
531 void SetPriority(unsigned int prio);
532
533 // Get the current priority.
534 unsigned int GetPriority() const;
535
536 // thread status inquiries
537 // Returns true if the thread is alive: i.e. running or suspended
538 bool IsAlive() const;
539 // Returns true if the thread is running (not paused, not killed).
540 bool IsRunning() const;
541 // Returns true if the thread is suspended
542 bool IsPaused() const;
543
544 // is the thread of detached kind?
545 bool IsDetached() const { return m_isDetached; }
546
547 // Get the thread ID - a platform dependent number which uniquely
548 // identifies a thread inside a process
549 wxThreadIdType GetId() const;
550
551 // called when the thread exits - in the context of this thread
552 //
553 // NB: this function will not be called if the thread is Kill()ed
554 virtual void OnExit() { }
555
556 // Returns true if the thread was asked to terminate: this function should
557 // be called by the thread from time to time, otherwise the main thread
558 // will be left forever in Delete()!
559 virtual bool TestDestroy();
560
561 // dtor is public, but the detached threads should never be deleted - use
562 // Delete() instead (or leave the thread terminate by itself)
563 virtual ~wxThread();
564
565 protected:
566 // exits from the current thread - can be called only from this thread
567 void Exit(ExitCode exitcode = 0);
568
569 // entry point for the thread - called by Run() and executes in the context
570 // of this thread.
571 virtual void *Entry() = 0;
572
573 private:
574 // no copy ctor/assignment operator
575 wxThread(const wxThread&);
576 wxThread& operator=(const wxThread&);
577
578 friend class wxThreadInternal;
579
580 // the (platform-dependent) thread class implementation
581 wxThreadInternal *m_internal;
582
583 // protects access to any methods of wxThreadInternal object
584 wxCriticalSection m_critsect;
585
586 // true if the thread is detached, false if it is joinable
587 bool m_isDetached;
588 };
589
590 // wxThreadHelperThread class
591 // --------------------------
592
593 class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread
594 {
595 public:
596 // constructor only creates the C++ thread object and doesn't create (or
597 // start) the real thread
598 wxThreadHelperThread(wxThreadHelper& owner, wxThreadKind kind)
599 : wxThread(kind), m_owner(owner)
600 { }
601
602 protected:
603 // entry point for the thread -- calls Entry() in owner.
604 virtual void *Entry();
605
606 private:
607 // the owner of the thread
608 wxThreadHelper& m_owner;
609
610 // no copy ctor/assignment operator
611 wxThreadHelperThread(const wxThreadHelperThread&);
612 wxThreadHelperThread& operator=(const wxThreadHelperThread&);
613 };
614
615 // ----------------------------------------------------------------------------
616 // wxThreadHelper: this class implements the threading logic to run a
617 // background task in another object (such as a window). It is a mix-in: just
618 // derive from it to implement a threading background task in your class.
619 // ----------------------------------------------------------------------------
620
621 class WXDLLIMPEXP_BASE wxThreadHelper
622 {
623 private:
624 void KillThread()
625 {
626 // If detached thread is about to finish, it will set
627 // m_thread to NULL so don't delete it then
628 // But if KillThread is called before detached thread
629 // sets it to NULL, then the thread object still
630 // exists and can be killed
631 wxCriticalSectionLocker locker(m_critSection);
632
633 if ( m_thread )
634 {
635 m_thread->Kill();
636
637 if ( m_kind == wxTHREAD_JOINABLE )
638 delete m_thread;
639
640 m_thread = NULL;
641 }
642 }
643
644 public:
645 // constructor only initializes m_thread to NULL
646 wxThreadHelper(wxThreadKind kind = wxTHREAD_JOINABLE)
647 : m_thread(NULL), m_kind(kind) { }
648
649 // destructor deletes m_thread
650 virtual ~wxThreadHelper() { KillThread(); }
651
652 // create a new thread (and optionally set the stack size on platforms that
653 // support/need that), call Run() to start it
654 wxThreadError Create(unsigned int stackSize = 0)
655 {
656 KillThread();
657
658 m_thread = new wxThreadHelperThread(*this, m_kind);
659
660 return m_thread->Create(stackSize);
661 }
662
663 // entry point for the thread - called by Run() and executes in the context
664 // of this thread.
665 virtual void *Entry() = 0;
666
667 // returns a pointer to the thread which can be used to call Run()
668 wxThread *GetThread() const
669 {
670 wxCriticalSectionLocker locker((wxCriticalSection&)m_critSection);
671
672 wxThread* thread = m_thread;
673
674 return thread;
675 }
676
677 protected:
678 wxThread *m_thread;
679 wxThreadKind m_kind;
680 wxCriticalSection m_critSection; // To guard the m_thread variable
681
682 friend class wxThreadHelperThread;
683 };
684
685 // call Entry() in owner, put it down here to avoid circular declarations
686 inline void *wxThreadHelperThread::Entry()
687 {
688 void * const result = m_owner.Entry();
689
690 wxCriticalSectionLocker locker(m_owner.m_critSection);
691
692 // Detached thread will be deleted after returning, so make sure
693 // wxThreadHelper::GetThread will not return an invalid pointer.
694 // And that wxThreadHelper::KillThread will not try to kill
695 // an already deleted thread
696 if ( m_owner.m_kind == wxTHREAD_DETACHED )
697 m_owner.m_thread = NULL;
698
699 return result;
700 }
701
702 // ----------------------------------------------------------------------------
703 // Automatic initialization
704 // ----------------------------------------------------------------------------
705
706 // GUI mutex handling.
707 void WXDLLIMPEXP_BASE wxMutexGuiEnter();
708 void WXDLLIMPEXP_BASE wxMutexGuiLeave();
709
710 // macros for entering/leaving critical sections which may be used without
711 // having to take them inside "#if wxUSE_THREADS"
712 #define wxENTER_CRIT_SECT(cs) (cs).Enter()
713 #define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
714 #define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
715 #define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs
716 #define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
717
718 // function for checking if we're in the main thread which may be used whether
719 // wxUSE_THREADS is 0 or 1
720 inline bool wxIsMainThread() { return wxThread::IsMain(); }
721
722 #else // !wxUSE_THREADS
723
724 // no thread support
725 inline void wxMutexGuiEnter() { }
726 inline void wxMutexGuiLeave() { }
727
728 // macros for entering/leaving critical sections which may be used without
729 // having to take them inside "#if wxUSE_THREADS"
730 // (the implementation uses dummy structs to force semicolon after the macro)
731 #define wxENTER_CRIT_SECT(cs) do {} while (0)
732 #define wxLEAVE_CRIT_SECT(cs) do {} while (0)
733 #define wxCRIT_SECT_DECLARE(cs) struct wxDummyCS##cs
734 #define wxCRIT_SECT_DECLARE_MEMBER(cs) struct wxDummyCSMember##cs
735 #define wxCRIT_SECT_LOCKER(name, cs) struct wxDummyCSLocker##name
736
737 // if there is only one thread, it is always the main one
738 inline bool wxIsMainThread() { return true; }
739
740 #endif // wxUSE_THREADS/!wxUSE_THREADS
741
742 // mark part of code as being a critical section: this macro declares a
743 // critical section with the given name and enters it immediately and leaves
744 // it at the end of the current scope
745 //
746 // example:
747 //
748 // int Count()
749 // {
750 // static int s_counter = 0;
751 //
752 // wxCRITICAL_SECTION(counter);
753 //
754 // return ++s_counter;
755 // }
756 //
757 // this function is MT-safe in presence of the threads but there is no
758 // overhead when the library is compiled without threads
759 #define wxCRITICAL_SECTION(name) \
760 wxCRIT_SECT_DECLARE(s_cs##name); \
761 wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name)
762
763 // automatically lock GUI mutex in ctor and unlock it in dtor
764 class WXDLLIMPEXP_BASE wxMutexGuiLocker
765 {
766 public:
767 wxMutexGuiLocker() { wxMutexGuiEnter(); }
768 ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
769 };
770
771 // -----------------------------------------------------------------------------
772 // implementation only until the end of file
773 // -----------------------------------------------------------------------------
774
775 #if wxUSE_THREADS
776
777 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__OS2__) || defined(__EMX__)
778 // unlock GUI if there are threads waiting for and lock it back when
779 // there are no more of them - should be called periodically by the main
780 // thread
781 extern void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter();
782
783 // returns true if the main thread has GUI lock
784 extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread();
785
786 // wakes up the main thread if it's sleeping inside ::GetMessage()
787 extern void WXDLLIMPEXP_BASE wxWakeUpMainThread();
788
789 // return true if the main thread is waiting for some other to terminate:
790 // wxApp then should block all "dangerous" messages
791 extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread();
792 #endif // MSW, Mac, OS/2
793
794 #endif // wxUSE_THREADS
795
796 #endif // _WX_THREAD_H_