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