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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(__APPLE__)
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__) && !defined(__WXPM__)
213 #define wxCRITSECT_IS_MUTEX 1
214
215 #define wxCRITSECT_INLINE inline
216 #else // MSW || OS2
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 #else
261 // nothing for OS/2
262 #endif // Unix/Win32/OS2
263
264 DECLARE_NO_COPY_CLASS(wxCriticalSection)
265 };
266
267 #if wxCRITSECT_IS_MUTEX
268 // implement wxCriticalSection using mutexes
269 inline wxCriticalSection::wxCriticalSection() { }
270 inline wxCriticalSection::~wxCriticalSection() { }
271
272 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
273 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
274 #endif // wxCRITSECT_IS_MUTEX
275
276 #undef wxCRITSECT_INLINE
277 #undef wxCRITSECT_IS_MUTEX
278
279 // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
280 // to th mutexes
281 class WXDLLIMPEXP_BASE wxCriticalSectionLocker
282 {
283 public:
284 wxCriticalSectionLocker(wxCriticalSection& cs)
285 : m_critsect(cs)
286 {
287 m_critsect.Enter();
288 }
289
290 ~wxCriticalSectionLocker()
291 {
292 m_critsect.Leave();
293 }
294
295 private:
296 wxCriticalSection& m_critsect;
297
298 DECLARE_NO_COPY_CLASS(wxCriticalSectionLocker)
299 };
300
301 // ----------------------------------------------------------------------------
302 // wxCondition models a POSIX condition variable which allows one (or more)
303 // thread(s) to wait until some condition is fulfilled
304 // ----------------------------------------------------------------------------
305
306 class WXDLLIMPEXP_BASE wxCondition
307 {
308 public:
309 // Each wxCondition object is associated with a (single) wxMutex object.
310 // The mutex object MUST be locked before calling Wait()
311 wxCondition(wxMutex& mutex);
312
313 // dtor is not virtual, don't use this class polymorphically
314 ~wxCondition();
315
316 // return TRUE if the condition has been created successfully
317 bool IsOk() const;
318
319 // NB: the associated mutex MUST be locked beforehand by the calling thread
320 //
321 // it atomically releases the lock on the associated mutex
322 // and starts waiting to be woken up by a Signal()/Broadcast()
323 // once its signaled, then it will wait until it can reacquire
324 // the lock on the associated mutex object, before returning.
325 wxCondError Wait();
326
327 // exactly as Wait() except that it may also return if the specified
328 // timeout ellapses even if the condition hasn't been signalled: in this
329 // case, the return value is FALSE, otherwise (i.e. in case of a normal
330 // return) it is TRUE
331 //
332 // the timeeout parameter specifies a interval that needs to be waited in
333 // milliseconds
334 wxCondError WaitTimeout(unsigned long milliseconds);
335
336 // NB: the associated mutex may or may not be locked by the calling thread
337 //
338 // this method unblocks one thread if any are blocking on the condition.
339 // if no thread is blocking in Wait(), then the signal is NOT remembered
340 // The thread which was blocking on Wait(), will then reacquire the lock
341 // on the associated mutex object before returning
342 wxCondError Signal();
343
344 // NB: the associated mutex may or may not be locked by the calling thread
345 //
346 // this method unblocks all threads if any are blocking on the condition.
347 // if no thread is blocking in Wait(), then the signal is NOT remembered
348 // The threads which were blocking on Wait(), will then reacquire the lock
349 // on the associated mutex object before returning.
350 wxCondError Broadcast();
351
352
353 // deprecated version, don't use
354 bool Wait(unsigned long milliseconds)
355 { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; }
356
357 private:
358 wxConditionInternal *m_internal;
359
360 DECLARE_NO_COPY_CLASS(wxCondition)
361 };
362
363 // ----------------------------------------------------------------------------
364 // wxSemaphore: a counter limiting the number of threads concurrently accessing
365 // a shared resource
366 // ----------------------------------------------------------------------------
367
368 class WXDLLIMPEXP_BASE wxSemaphore
369 {
370 public:
371 // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
372 // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
373 wxSemaphore( int initialcount = 0, int maxcount = 0 );
374
375 // dtor is not virtual, don't use this class polymorphically
376 ~wxSemaphore();
377
378 // return TRUE if the semaphore has been created successfully
379 bool IsOk() const;
380
381 // wait indefinitely, until the semaphore count goes beyond 0
382 // and then decrement it and return (this method might have been called
383 // Acquire())
384 wxSemaError Wait();
385
386 // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if
387 // successful and wxSEMA_BUSY if the count is currently zero
388 wxSemaError TryWait();
389
390 // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the
391 // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has ellapsed
392 wxSemaError WaitTimeout(unsigned long milliseconds);
393
394 // increments the semaphore count and signals one of the waiting threads
395 wxSemaError Post();
396
397 private:
398 wxSemaphoreInternal *m_internal;
399
400 DECLARE_NO_COPY_CLASS(wxSemaphore)
401 };
402
403 // ----------------------------------------------------------------------------
404 // wxThread: class encpasulating a thread of execution
405 // ----------------------------------------------------------------------------
406
407 // there are two different kinds of threads: joinable and detached (default)
408 // ones. Only joinable threads can return a return code and only detached
409 // threads auto-delete themselves - the user should delete the joinable
410 // threads manually.
411
412 // NB: in the function descriptions the words "this thread" mean the thread
413 // created by the wxThread object while "main thread" is the thread created
414 // during the process initialization (a.k.a. the GUI thread)
415
416 // On VMS thread pointers are 64 bits (also needed for other systems???
417 #ifdef __VMS
418 typedef unsigned long long wxThreadIdType;
419 #else
420 typedef unsigned long wxThreadIdType;
421 #endif
422
423 class WXDLLIMPEXP_BASE wxThread
424 {
425 public:
426 // the return type for the thread function
427 typedef void *ExitCode;
428
429 // static functions
430 // Returns the wxThread object for the calling thread. NULL is returned
431 // if the caller is the main thread (but it's recommended to use
432 // IsMain() and only call This() for threads other than the main one
433 // because NULL is also returned on error). If the thread wasn't
434 // created with wxThread class, the returned value is undefined.
435 static wxThread *This();
436
437 // Returns true if current thread is the main thread.
438 static bool IsMain();
439
440 // Release the rest of our time slice leting the other threads run
441 static void Yield();
442
443 // Sleep during the specified period of time in milliseconds
444 //
445 // NB: at least under MSW worker threads can not call ::wxSleep()!
446 static void Sleep(unsigned long milliseconds);
447
448 // get the number of system CPUs - useful with SetConcurrency()
449 // (the "best" value for it is usually number of CPUs + 1)
450 //
451 // Returns -1 if unknown, number of CPUs otherwise
452 static int GetCPUCount();
453
454 // Get the platform specific thread ID and return as a long. This
455 // can be used to uniquely identify threads, even if they are not
456 // wxThreads. This is used by wxPython.
457 static wxThreadIdType GetCurrentId();
458
459 // sets the concurrency level: this is, roughly, the number of threads
460 // the system tries to schedule to run in parallel. 0 means the
461 // default value (usually acceptable, but may not yield the best
462 // performance for this process)
463 //
464 // Returns TRUE on success, FALSE otherwise (if not implemented, for
465 // example)
466 static bool SetConcurrency(size_t level);
467
468 // constructor only creates the C++ thread object and doesn't create (or
469 // start) the real thread
470 wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
471
472 // functions that change the thread state: all these can only be called
473 // from _another_ thread (typically the thread that created this one, e.g.
474 // the main thread), not from the thread itself
475
476 // create a new thread and optionally set the stack size on
477 // platforms that support that - call Run() to start it
478 // (special cased for watcom which won't accept 0 default)
479
480 wxThreadError Create(unsigned int stackSize = 0);
481
482 // starts execution of the thread - from the moment Run() is called
483 // the execution of wxThread::Entry() may start at any moment, caller
484 // shouldn't suppose that it starts after (or before) Run() returns.
485 wxThreadError Run();
486
487 // stops the thread if it's running and deletes the wxThread object if
488 // this is a detached thread freeing its memory - otherwise (for
489 // joinable threads) you still need to delete wxThread object
490 // yourself.
491 //
492 // this function only works if the thread calls TestDestroy()
493 // periodically - the thread will only be deleted the next time it
494 // does it!
495 //
496 // will fill the rc pointer with the thread exit code if it's !NULL
497 wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
498
499 // waits for a joinable thread to finish and returns its exit code
500 //
501 // Returns (ExitCode)-1 on error (for example, if the thread is not
502 // joinable)
503 ExitCode Wait();
504
505 // kills the thread without giving it any chance to clean up - should
506 // not be used in normal circumstances, use Delete() instead. It is a
507 // dangerous function that should only be used in the most extreme
508 // cases!
509 //
510 // The wxThread object is deleted by Kill() if the thread is
511 // detachable, but you still have to delete it manually for joinable
512 // threads.
513 wxThreadError Kill();
514
515 // pause a running thread: as Delete(), this only works if the thread
516 // calls TestDestroy() regularly
517 wxThreadError Pause();
518
519 // resume a paused thread
520 wxThreadError Resume();
521
522 // priority
523 // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
524 //
525 // NB: the priority can only be set before the thread is created
526 void SetPriority(unsigned int prio);
527
528 // Get the current priority.
529 unsigned int GetPriority() const;
530
531 // thread status inquiries
532 // Returns true if the thread is alive: i.e. running or suspended
533 bool IsAlive() const;
534 // Returns true if the thread is running (not paused, not killed).
535 bool IsRunning() const;
536 // Returns true if the thread is suspended
537 bool IsPaused() const;
538
539 // is the thread of detached kind?
540 bool IsDetached() const { return m_isDetached; }
541
542 // Get the thread ID - a platform dependent number which uniquely
543 // identifies a thread inside a process
544 wxThreadIdType GetId() const;
545
546 // called when the thread exits - in the context of this thread
547 //
548 // NB: this function will not be called if the thread is Kill()ed
549 virtual void OnExit() { }
550
551 // dtor is public, but the detached threads should never be deleted - use
552 // Delete() instead (or leave the thread terminate by itself)
553 virtual ~wxThread();
554
555 protected:
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 bool TestDestroy();
560
561 // exits from the current thread - can be called only from this thread
562 void Exit(ExitCode exitcode = 0);
563
564 // entry point for the thread - called by Run() and executes in the context
565 // of this thread.
566 virtual void *Entry() = 0;
567
568 private:
569 // no copy ctor/assignment operator
570 wxThread(const wxThread&);
571 wxThread& operator=(const wxThread&);
572
573 friend class wxThreadInternal;
574
575 // the (platform-dependent) thread class implementation
576 wxThreadInternal *m_internal;
577
578 // protects access to any methods of wxThreadInternal object
579 wxCriticalSection m_critsect;
580
581 // true if the thread is detached, false if it is joinable
582 bool m_isDetached;
583 };
584
585 // wxThreadHelperThread class
586 // --------------------------
587
588 class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread
589 {
590 public:
591 // constructor only creates the C++ thread object and doesn't create (or
592 // start) the real thread
593 wxThreadHelperThread(wxThreadHelper& owner)
594 : wxThread(wxTHREAD_JOINABLE), m_owner(owner)
595 { }
596
597 protected:
598 // entry point for the thread -- calls Entry() in owner.
599 virtual void *Entry();
600
601 private:
602 // the owner of the thread
603 wxThreadHelper& m_owner;
604
605 // no copy ctor/assignment operator
606 wxThreadHelperThread(const wxThreadHelperThread&);
607 wxThreadHelperThread& operator=(const wxThreadHelperThread&);
608 };
609
610 // ----------------------------------------------------------------------------
611 // wxThreadHelper: this class implements the threading logic to run a
612 // background task in another object (such as a window). It is a mix-in: just
613 // derive from it to implement a threading background task in your class.
614 // ----------------------------------------------------------------------------
615
616 class WXDLLIMPEXP_BASE wxThreadHelper
617 {
618 private:
619 void KillThread()
620 {
621 if ( m_thread )
622 {
623 m_thread->Kill();
624 delete m_thread;
625 }
626 }
627
628 public:
629 // constructor only initializes m_thread to NULL
630 wxThreadHelper() : m_thread(NULL) { }
631
632 // destructor deletes m_thread
633 virtual ~wxThreadHelper() { KillThread(); }
634
635 // create a new thread (and optionally set the stack size on platforms that
636 // support/need that), call Run() to start it
637 wxThreadError Create(unsigned int stackSize = 0)
638 {
639 KillThread();
640
641 m_thread = new wxThreadHelperThread(*this);
642
643 return m_thread->Create(stackSize);
644 }
645
646 // entry point for the thread - called by Run() and executes in the context
647 // of this thread.
648 virtual void *Entry() = 0;
649
650 // returns a pointer to the thread which can be used to call Run()
651 wxThread *GetThread() const { return m_thread; }
652
653 protected:
654 wxThread *m_thread;
655 };
656
657 // call Entry() in owner, put it down here to avoid circular declarations
658 inline void *wxThreadHelperThread::Entry()
659 {
660 return m_owner.Entry();
661 }
662
663 // ----------------------------------------------------------------------------
664 // Automatic initialization
665 // ----------------------------------------------------------------------------
666
667 // GUI mutex handling.
668 void WXDLLIMPEXP_BASE wxMutexGuiEnter();
669 void WXDLLIMPEXP_BASE wxMutexGuiLeave();
670
671 // macros for entering/leaving critical sections which may be used without
672 // having to take them inside "#if wxUSE_THREADS"
673 #define wxENTER_CRIT_SECT(cs) (cs).Enter()
674 #define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
675 #define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
676 #define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs
677 #define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
678
679 // function for checking if we're in the main thread which may be used whether
680 // wxUSE_THREADS is 0 or 1
681 inline bool wxIsMainThread() { return wxThread::IsMain(); }
682
683 #else // !wxUSE_THREADS
684
685 // no thread support
686 inline void WXDLLIMPEXP_BASE wxMutexGuiEnter() { }
687 inline void WXDLLIMPEXP_BASE wxMutexGuiLeave() { }
688
689 // macros for entering/leaving critical sections which may be used without
690 // having to take them inside "#if wxUSE_THREADS"
691 #define wxENTER_CRIT_SECT(cs)
692 #define wxLEAVE_CRIT_SECT(cs)
693 #define wxCRIT_SECT_DECLARE(cs)
694 #define wxCRIT_SECT_DECLARE_MEMBER(cs)
695 #define wxCRIT_SECT_LOCKER(name, cs)
696
697 // if there is only one thread, it is always the main one
698 inline bool wxIsMainThread() { return true; }
699
700 #endif // wxUSE_THREADS/!wxUSE_THREADS
701
702 // mark part of code as being a critical section: this macro declares a
703 // critical section with the given name and enters it immediately and leaves
704 // it at the end of the current scope
705 //
706 // example:
707 //
708 // int Count()
709 // {
710 // static int s_counter = 0;
711 //
712 // wxCRITICAL_SECTION(counter);
713 //
714 // return ++s_counter;
715 // }
716 //
717 // this function is MT-safe in presence of the threads but there is no
718 // overhead when the library is compiled without threads
719 #define wxCRITICAL_SECTION(name) \
720 wxCRIT_SECT_DECLARE(s_cs##name); \
721 wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name)
722
723 // automatically lock GUI mutex in ctor and unlock it in dtor
724 class WXDLLIMPEXP_BASE wxMutexGuiLocker
725 {
726 public:
727 wxMutexGuiLocker() { wxMutexGuiEnter(); }
728 ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
729 };
730
731 // -----------------------------------------------------------------------------
732 // implementation only until the end of file
733 // -----------------------------------------------------------------------------
734
735 #if wxUSE_THREADS
736
737 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXPM__)
738 // unlock GUI if there are threads waiting for and lock it back when
739 // there are no more of them - should be called periodically by the main
740 // thread
741 extern void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter();
742
743 // returns TRUE if the main thread has GUI lock
744 extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread();
745
746 #ifndef __WXPM__
747 // wakes up the main thread if it's sleeping inside ::GetMessage()
748 extern void WXDLLIMPEXP_BASE wxWakeUpMainThread();
749 #endif // !OS/2
750
751 // return TRUE if the main thread is waiting for some other to terminate:
752 // wxApp then should block all "dangerous" messages
753 extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread();
754 #endif // MSW, Mac, OS/2
755
756 #endif // wxUSE_THREADS
757
758 #endif // _WX_THREAD_H_
759