///////////////////////////////////////////////////////////////////////////// // Name: wx/thread.h // Purpose: Thread API // Author: Guilhem Lavaux // Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads // package from Olivetti & Oracle Research Laboratory) // Created: 04/13/98 // RCS-ID: $Id$ // Copyright: (c) Guilhem Lavaux // Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// #ifndef _WX_THREAD_H_ #define _WX_THREAD_H_ // ---------------------------------------------------------------------------- // headers // ---------------------------------------------------------------------------- // get the value of wxUSE_THREADS configuration flag #include "wx/defs.h" #if wxUSE_THREADS // ---------------------------------------------------------------------------- // constants // ---------------------------------------------------------------------------- enum wxMutexError { wxMUTEX_NO_ERROR = 0, // operation completed successfully wxMUTEX_INVALID, // mutex hasn't been initialized wxMUTEX_DEAD_LOCK, // mutex is already locked by the calling thread wxMUTEX_BUSY, // mutex is already locked by another thread wxMUTEX_UNLOCKED, // attempt to unlock a mutex which is not locked wxMUTEX_TIMEOUT, // LockTimeout() has timed out wxMUTEX_MISC_ERROR // any other error }; enum wxCondError { wxCOND_NO_ERROR = 0, wxCOND_INVALID, wxCOND_TIMEOUT, // WaitTimeout() has timed out wxCOND_MISC_ERROR }; enum wxSemaError { wxSEMA_NO_ERROR = 0, wxSEMA_INVALID, // semaphore hasn't been initialized successfully wxSEMA_BUSY, // returned by TryWait() if Wait() would block wxSEMA_TIMEOUT, // returned by WaitTimeout() wxSEMA_OVERFLOW, // Post() would increase counter past the max wxSEMA_MISC_ERROR }; enum wxThreadError { wxTHREAD_NO_ERROR = 0, // No error wxTHREAD_NO_RESOURCE, // No resource left to create a new thread wxTHREAD_RUNNING, // The thread is already running wxTHREAD_NOT_RUNNING, // The thread isn't running wxTHREAD_KILLED, // Thread we waited for had to be killed wxTHREAD_MISC_ERROR // Some other error }; enum wxThreadKind { wxTHREAD_DETACHED, wxTHREAD_JOINABLE }; enum wxThreadWait { wxTHREAD_WAIT_BLOCK, wxTHREAD_WAIT_YIELD, // process events while waiting; MSW only // For compatibility reasons we use wxTHREAD_WAIT_YIELD by default as this // was the default behaviour of wxMSW 2.8 but it should be avoided as it's // dangerous and not portable. #if WXWIN_COMPATIBILITY_2_8 wxTHREAD_WAIT_DEFAULT = wxTHREAD_WAIT_YIELD #else wxTHREAD_WAIT_DEFAULT = wxTHREAD_WAIT_BLOCK #endif }; // Obsolete synonyms for wxPRIORITY_XXX for backwards compatibility-only enum { WXTHREAD_MIN_PRIORITY = wxPRIORITY_MIN, WXTHREAD_DEFAULT_PRIORITY = wxPRIORITY_DEFAULT, WXTHREAD_MAX_PRIORITY = wxPRIORITY_MAX }; // There are 2 types of mutexes: normal mutexes and recursive ones. The attempt // to lock a normal mutex by a thread which already owns it results in // undefined behaviour (it always works under Windows, it will almost always // result in a deadlock under Unix). Locking a recursive mutex in such // situation always succeeds and it must be unlocked as many times as it has // been locked. // // However recursive mutexes have several important drawbacks: first, in the // POSIX implementation, they're less efficient. Second, and more importantly, // they CAN NOT BE USED WITH CONDITION VARIABLES under Unix! Using them with // wxCondition will work under Windows and some Unices (notably Linux) but will // deadlock under other Unix versions (e.g. Solaris). As it might be difficult // to ensure that a recursive mutex is not used with wxCondition, it is a good // idea to avoid using recursive mutexes at all. Also, the last problem with // them is that some (older) Unix versions don't support this at all -- which // results in a configure warning when building and a deadlock when using them. enum wxMutexType { // normal mutex: try to always use this one wxMUTEX_DEFAULT, // recursive mutex: don't use these ones with wxCondition wxMUTEX_RECURSIVE }; // forward declarations class WXDLLIMPEXP_FWD_BASE wxThreadHelper; class WXDLLIMPEXP_FWD_BASE wxConditionInternal; class WXDLLIMPEXP_FWD_BASE wxMutexInternal; class WXDLLIMPEXP_FWD_BASE wxSemaphoreInternal; class WXDLLIMPEXP_FWD_BASE wxThreadInternal; // ---------------------------------------------------------------------------- // A mutex object is a synchronization object whose state is set to signaled // when it is not owned by any thread, and nonsignaled when it is owned. Its // name comes from its usefulness in coordinating mutually-exclusive access to // a shared resource. Only one thread at a time can own a mutex object. // ---------------------------------------------------------------------------- // you should consider wxMutexLocker whenever possible instead of directly // working with wxMutex class - it is safer class WXDLLIMPEXP_BASE wxMutex { public: // constructor & destructor // ------------------------ // create either default (always safe) or recursive mutex wxMutex(wxMutexType mutexType = wxMUTEX_DEFAULT); // destroys the mutex kernel object ~wxMutex(); // test if the mutex has been created successfully bool IsOk() const; // mutex operations // ---------------- // Lock the mutex, blocking on it until it is unlocked by the other thread. // The result of locking a mutex already locked by the current thread // depend on the mutex type. // // The caller must call Unlock() later if Lock() returned wxMUTEX_NO_ERROR. wxMutexError Lock(); // Same as Lock() but return wxMUTEX_TIMEOUT if the mutex can't be locked // during the given number of milliseconds wxMutexError LockTimeout(unsigned long ms); // Try to lock the mutex: if it is currently locked, return immediately // with an error. Otherwise the caller must call Unlock(). wxMutexError TryLock(); // Unlock the mutex. It is an error to unlock an already unlocked mutex wxMutexError Unlock(); protected: wxMutexInternal *m_internal; friend class wxConditionInternal; wxDECLARE_NO_COPY_CLASS(wxMutex); }; // a helper class which locks the mutex in the ctor and unlocks it in the dtor: // this ensures that mutex is always unlocked, even if the function returns or // throws an exception before it reaches the end class WXDLLIMPEXP_BASE wxMutexLocker { public: // lock the mutex in the ctor wxMutexLocker(wxMutex& mutex) : m_isOk(false), m_mutex(mutex) { m_isOk = ( m_mutex.Lock() == wxMUTEX_NO_ERROR ); } // returns true if mutex was successfully locked in ctor bool IsOk() const { return m_isOk; } // unlock the mutex in dtor ~wxMutexLocker() { if ( IsOk() ) m_mutex.Unlock(); } private: // no assignment operator nor copy ctor wxMutexLocker(const wxMutexLocker&); wxMutexLocker& operator=(const wxMutexLocker&); bool m_isOk; wxMutex& m_mutex; }; // ---------------------------------------------------------------------------- // Critical section: this is the same as mutex but is only visible to the // threads of the same process. For the platforms which don't have native // support for critical sections, they're implemented entirely in terms of // mutexes. // // NB: wxCriticalSection object does not allocate any memory in its ctor // which makes it possible to have static globals of this class // ---------------------------------------------------------------------------- // in order to avoid any overhead under platforms where critical sections are // just mutexes make all wxCriticalSection class functions inline #if !defined(__WINDOWS__) #define wxCRITSECT_IS_MUTEX 1 #define wxCRITSECT_INLINE WXEXPORT inline #else // MSW #define wxCRITSECT_IS_MUTEX 0 #define wxCRITSECT_INLINE #endif // MSW/!MSW enum wxCriticalSectionType { // recursive critical section wxCRITSEC_DEFAULT, // non-recursive critical section wxCRITSEC_NON_RECURSIVE }; // you should consider wxCriticalSectionLocker whenever possible instead of // directly working with wxCriticalSection class - it is safer class WXDLLIMPEXP_BASE wxCriticalSection { public: // ctor & dtor wxCRITSECT_INLINE wxCriticalSection( wxCriticalSectionType critSecType = wxCRITSEC_DEFAULT ); wxCRITSECT_INLINE ~wxCriticalSection(); // enter the section (the same as locking a mutex) wxCRITSECT_INLINE void Enter(); // try to enter the section (the same as trying to lock a mutex) wxCRITSECT_INLINE bool TryEnter(); // leave the critical section (same as unlocking a mutex) wxCRITSECT_INLINE void Leave(); private: #if wxCRITSECT_IS_MUTEX wxMutex m_mutex; #elif defined(__WINDOWS__) // we can't allocate any memory in the ctor, so use placement new - // unfortunately, we have to hardcode the sizeof() here because we can't // include windows.h from this public header and we also have to use the // union to force the correct (i.e. maximal) alignment // // if CRITICAL_SECTION size changes in Windows, you'll get an assert from // thread.cpp and will need to increase the buffer size #ifdef __WIN64__ typedef char wxCritSectBuffer[40]; #else // __WIN32__ typedef char wxCritSectBuffer[24]; #endif union { unsigned long m_dummy1; void *m_dummy2; wxCritSectBuffer m_buffer; }; #endif // Unix&OS2/Win32 wxDECLARE_NO_COPY_CLASS(wxCriticalSection); }; #if wxCRITSECT_IS_MUTEX // implement wxCriticalSection using mutexes inline wxCriticalSection::wxCriticalSection( wxCriticalSectionType critSecType ) : m_mutex( critSecType == wxCRITSEC_DEFAULT ? wxMUTEX_RECURSIVE : wxMUTEX_DEFAULT ) { } inline wxCriticalSection::~wxCriticalSection() { } inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); } inline bool wxCriticalSection::TryEnter() { return m_mutex.TryLock() == wxMUTEX_NO_ERROR; } inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); } #endif // wxCRITSECT_IS_MUTEX #undef wxCRITSECT_INLINE #undef wxCRITSECT_IS_MUTEX // wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is // to mutexes class WXDLLIMPEXP_BASE wxCriticalSectionLocker { public: wxCriticalSectionLocker(wxCriticalSection& cs) : m_critsect(cs) { m_critsect.Enter(); } ~wxCriticalSectionLocker() { m_critsect.Leave(); } private: wxCriticalSection& m_critsect; wxDECLARE_NO_COPY_CLASS(wxCriticalSectionLocker); }; // ---------------------------------------------------------------------------- // wxCondition models a POSIX condition variable which allows one (or more) // thread(s) to wait until some condition is fulfilled // ---------------------------------------------------------------------------- class WXDLLIMPEXP_BASE wxCondition { public: // Each wxCondition object is associated with a (single) wxMutex object. // The mutex object MUST be locked before calling Wait() wxCondition(wxMutex& mutex); // dtor is not virtual, don't use this class polymorphically ~wxCondition(); // return true if the condition has been created successfully bool IsOk() const; // NB: the associated mutex MUST be locked beforehand by the calling thread // // it atomically releases the lock on the associated mutex // and starts waiting to be woken up by a Signal()/Broadcast() // once its signaled, then it will wait until it can reacquire // the lock on the associated mutex object, before returning. wxCondError Wait(); // exactly as Wait() except that it may also return if the specified // timeout elapses even if the condition hasn't been signalled: in this // case, the return value is false, otherwise (i.e. in case of a normal // return) it is true // // the timeout parameter specifies an interval that needs to be waited for // in milliseconds wxCondError WaitTimeout(unsigned long milliseconds); // NB: the associated mutex may or may not be locked by the calling thread // // this method unblocks one thread if any are blocking on the condition. // if no thread is blocking in Wait(), then the signal is NOT remembered // The thread which was blocking on Wait() will then reacquire the lock // on the associated mutex object before returning wxCondError Signal(); // NB: the associated mutex may or may not be locked by the calling thread // // this method unblocks all threads if any are blocking on the condition. // if no thread is blocking in Wait(), then the signal is NOT remembered // The threads which were blocking on Wait() will then reacquire the lock // on the associated mutex object before returning. wxCondError Broadcast(); #if WXWIN_COMPATIBILITY_2_6 // deprecated version, don't use wxDEPRECATED( bool Wait(unsigned long milliseconds) ); #endif // WXWIN_COMPATIBILITY_2_6 private: wxConditionInternal *m_internal; wxDECLARE_NO_COPY_CLASS(wxCondition); }; #if WXWIN_COMPATIBILITY_2_6 inline bool wxCondition::Wait(unsigned long milliseconds) { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; } #endif // WXWIN_COMPATIBILITY_2_6 // ---------------------------------------------------------------------------- // wxSemaphore: a counter limiting the number of threads concurrently accessing // a shared resource // ---------------------------------------------------------------------------- class WXDLLIMPEXP_BASE wxSemaphore { public: // specifying a maxcount of 0 actually makes wxSemaphore behave as if there // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex wxSemaphore( int initialcount = 0, int maxcount = 0 ); // dtor is not virtual, don't use this class polymorphically ~wxSemaphore(); // return true if the semaphore has been created successfully bool IsOk() const; // wait indefinitely, until the semaphore count goes beyond 0 // and then decrement it and return (this method might have been called // Acquire()) wxSemaError Wait(); // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if // successful and wxSEMA_BUSY if the count is currently zero wxSemaError TryWait(); // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has elapsed wxSemaError WaitTimeout(unsigned long milliseconds); // increments the semaphore count and signals one of the waiting threads wxSemaError Post(); private: wxSemaphoreInternal *m_internal; wxDECLARE_NO_COPY_CLASS(wxSemaphore); }; // ---------------------------------------------------------------------------- // wxThread: class encapsulating a thread of execution // ---------------------------------------------------------------------------- // there are two different kinds of threads: joinable and detached (default) // ones. Only joinable threads can return a return code and only detached // threads auto-delete themselves - the user should delete the joinable // threads manually. // NB: in the function descriptions the words "this thread" mean the thread // created by the wxThread object while "main thread" is the thread created // during the process initialization (a.k.a. the GUI thread) // On VMS thread pointers are 64 bits (also needed for other systems??? #ifdef __VMS typedef unsigned long long wxThreadIdType; #else typedef unsigned long wxThreadIdType; #endif class WXDLLIMPEXP_BASE wxThread { public: // the return type for the thread function typedef void *ExitCode; // static functions // Returns the wxThread object for the calling thread. NULL is returned // if the caller is the main thread (but it's recommended to use // IsMain() and only call This() for threads other than the main one // because NULL is also returned on error). If the thread wasn't // created with wxThread class, the returned value is undefined. static wxThread *This(); // Returns true if current thread is the main thread. // // Notice that it also returns true if main thread id hadn't been // initialized yet on the assumption that it's too early in wx startup // process for any other threads to have been created in this case. static bool IsMain() { return !ms_idMainThread || GetCurrentId() == ms_idMainThread; } // Return the main thread id static wxThreadIdType GetMainId() { return ms_idMainThread; } // Release the rest of our time slice letting the other threads run static void Yield(); // Sleep during the specified period of time in milliseconds // // This is the same as wxMilliSleep(). static void Sleep(unsigned long milliseconds); // get the number of system CPUs - useful with SetConcurrency() // (the "best" value for it is usually number of CPUs + 1) // // Returns -1 if unknown, number of CPUs otherwise static int GetCPUCount(); // Get the platform specific thread ID and return as a long. This // can be used to uniquely identify threads, even if they are not // wxThreads. This is used by wxPython. static wxThreadIdType GetCurrentId(); // sets the concurrency level: this is, roughly, the number of threads // the system tries to schedule to run in parallel. 0 means the // default value (usually acceptable, but may not yield the best // performance for this process) // // Returns true on success, false otherwise (if not implemented, for // example) static bool SetConcurrency(size_t level); // constructor only creates the C++ thread object and doesn't create (or // start) the real thread wxThread(wxThreadKind kind = wxTHREAD_DETACHED); // functions that change the thread state: all these can only be called // from _another_ thread (typically the thread that created this one, e.g. // the main thread), not from the thread itself // create a new thread and optionally set the stack size on // platforms that support that - call Run() to start it // (special cased for watcom which won't accept 0 default) wxThreadError Create(unsigned int stackSize = 0); // starts execution of the thread - from the moment Run() is called // the execution of wxThread::Entry() may start at any moment, caller // shouldn't suppose that it starts after (or before) Run() returns. wxThreadError Run(); // stops the thread if it's running and deletes the wxThread object if // this is a detached thread freeing its memory - otherwise (for // joinable threads) you still need to delete wxThread object // yourself. // // this function only works if the thread calls TestDestroy() // periodically - the thread will only be deleted the next time it // does it! // // will fill the rc pointer with the thread exit code if it's !NULL wxThreadError Delete(ExitCode *rc = NULL, wxThreadWait waitMode = wxTHREAD_WAIT_DEFAULT); // waits for a joinable thread to finish and returns its exit code // // Returns (ExitCode)-1 on error (for example, if the thread is not // joinable) ExitCode Wait(wxThreadWait waitMode = wxTHREAD_WAIT_DEFAULT); // kills the thread without giving it any chance to clean up - should // not be used under normal circumstances, use Delete() instead. // It is a dangerous function that should only be used in the most // extreme cases! // // The wxThread object is deleted by Kill() if the thread is // detachable, but you still have to delete it manually for joinable // threads. wxThreadError Kill(); // pause a running thread: as Delete(), this only works if the thread // calls TestDestroy() regularly wxThreadError Pause(); // resume a paused thread wxThreadError Resume(); // priority // Sets the priority to "prio" which must be in 0..100 range (see // also wxPRIORITY_XXX constants). // // NB: the priority can only be set before the thread is created void SetPriority(unsigned int prio); // Get the current priority. unsigned int GetPriority() const; // thread status inquiries // Returns true if the thread is alive: i.e. running or suspended bool IsAlive() const; // Returns true if the thread is running (not paused, not killed). bool IsRunning() const; // Returns true if the thread is suspended bool IsPaused() const; // is the thread of detached kind? bool IsDetached() const { return m_isDetached; } // Get the thread ID - a platform dependent number which uniquely // identifies a thread inside a process wxThreadIdType GetId() const; wxThreadKind GetKind() const { return m_isDetached ? wxTHREAD_DETACHED : wxTHREAD_JOINABLE; } // Returns true if the thread was asked to terminate: this function should // be called by the thread from time to time, otherwise the main thread // will be left forever in Delete()! virtual bool TestDestroy(); // dtor is public, but the detached threads should never be deleted - use // Delete() instead (or leave the thread terminate by itself) virtual ~wxThread(); protected: // exits from the current thread - can be called only from this thread void Exit(ExitCode exitcode = 0); // entry point for the thread - called by Run() and executes in the context // of this thread. virtual void *Entry() = 0; // Callbacks which may be overridden by the derived class to perform some // specific actions when the thread is deleted or killed. By default they // do nothing. // This one is called by Delete() before actually deleting the thread and // is executed in the context of the thread that called Delete(). virtual void OnDelete() {} // This one is called by Kill() before killing the thread and is executed // in the context of the thread that called Kill(). virtual void OnKill() {} private: // no copy ctor/assignment operator wxThread(const wxThread&); wxThread& operator=(const wxThread&); // called when the thread exits - in the context of this thread // // NB: this function will not be called if the thread is Kill()ed virtual void OnExit() { } friend class wxThreadInternal; friend class wxThreadModule; // the main thread identifier, should be set on startup static wxThreadIdType ms_idMainThread; // the (platform-dependent) thread class implementation wxThreadInternal *m_internal; // protects access to any methods of wxThreadInternal object wxCriticalSection m_critsect; // true if the thread is detached, false if it is joinable bool m_isDetached; }; // wxThreadHelperThread class // -------------------------- class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread { public: // constructor only creates the C++ thread object and doesn't create (or // start) the real thread wxThreadHelperThread(wxThreadHelper& owner, wxThreadKind kind) : wxThread(kind), m_owner(owner) { } protected: // entry point for the thread -- calls Entry() in owner. virtual void *Entry(); private: // the owner of the thread wxThreadHelper& m_owner; // no copy ctor/assignment operator wxThreadHelperThread(const wxThreadHelperThread&); wxThreadHelperThread& operator=(const wxThreadHelperThread&); }; // ---------------------------------------------------------------------------- // wxThreadHelper: this class implements the threading logic to run a // background task in another object (such as a window). It is a mix-in: just // derive from it to implement a threading background task in your class. // ---------------------------------------------------------------------------- class WXDLLIMPEXP_BASE wxThreadHelper { private: void KillThread() { // If wxThreadHelperThread is detached and is about to finish, it will // set m_thread to NULL so don't delete it then. // But if KillThread is called before wxThreadHelperThread (in detached mode) // sets it to NULL, then the thread object still exists and can be killed wxCriticalSectionLocker locker(m_critSection); if ( m_thread ) { m_thread->Kill(); if ( m_kind == wxTHREAD_JOINABLE ) delete m_thread; m_thread = NULL; } } public: // constructor only initializes m_thread to NULL wxThreadHelper(wxThreadKind kind = wxTHREAD_JOINABLE) : m_thread(NULL), m_kind(kind) { } // destructor deletes m_thread virtual ~wxThreadHelper() { KillThread(); } #if WXWIN_COMPATIBILITY_2_8 wxDEPRECATED( wxThreadError Create(unsigned int stackSize = 0) ); #endif // create a new thread (and optionally set the stack size on platforms that // support/need that), call Run() to start it wxThreadError CreateThread(wxThreadKind kind = wxTHREAD_JOINABLE, unsigned int stackSize = 0) { KillThread(); m_kind = kind; m_thread = new wxThreadHelperThread(*this, m_kind); return m_thread->Create(stackSize); } // entry point for the thread - called by Run() and executes in the context // of this thread. virtual void *Entry() = 0; // returns a pointer to the thread which can be used to call Run() wxThread *GetThread() const { wxCriticalSectionLocker locker((wxCriticalSection&)m_critSection); wxThread* thread = m_thread; return thread; } protected: wxThread *m_thread; wxThreadKind m_kind; wxCriticalSection m_critSection; // To guard the m_thread variable friend class wxThreadHelperThread; }; #if WXWIN_COMPATIBILITY_2_8 inline wxThreadError wxThreadHelper::Create(unsigned int stackSize) { return CreateThread(m_kind, stackSize); } #endif // call Entry() in owner, put it down here to avoid circular declarations inline void *wxThreadHelperThread::Entry() { void * const result = m_owner.Entry(); wxCriticalSectionLocker locker(m_owner.m_critSection); // Detached thread will be deleted after returning, so make sure // wxThreadHelper::GetThread will not return an invalid pointer. // And that wxThreadHelper::KillThread will not try to kill // an already deleted thread if ( m_owner.m_kind == wxTHREAD_DETACHED ) m_owner.m_thread = NULL; return result; } // ---------------------------------------------------------------------------- // Automatic initialization // ---------------------------------------------------------------------------- // GUI mutex handling. void WXDLLIMPEXP_BASE wxMutexGuiEnter(); void WXDLLIMPEXP_BASE wxMutexGuiLeave(); // macros for entering/leaving critical sections which may be used without // having to take them inside "#if wxUSE_THREADS" #define wxENTER_CRIT_SECT(cs) (cs).Enter() #define wxLEAVE_CRIT_SECT(cs) (cs).Leave() #define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs #define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs #define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs) // function for checking if we're in the main thread which may be used whether // wxUSE_THREADS is 0 or 1 inline bool wxIsMainThread() { return wxThread::IsMain(); } #else // !wxUSE_THREADS // no thread support inline void wxMutexGuiEnter() { } inline void wxMutexGuiLeave() { } // macros for entering/leaving critical sections which may be used without // having to take them inside "#if wxUSE_THREADS" // (the implementation uses dummy structs to force semicolon after the macro; // also notice that Watcom doesn't like declaring a struct as a member so we // need to actually define it in wxCRIT_SECT_DECLARE_MEMBER) #define wxENTER_CRIT_SECT(cs) do {} while (0) #define wxLEAVE_CRIT_SECT(cs) do {} while (0) #define wxCRIT_SECT_DECLARE(cs) struct wxDummyCS##cs #define wxCRIT_SECT_DECLARE_MEMBER(cs) struct wxDummyCSMember##cs { } #define wxCRIT_SECT_LOCKER(name, cs) struct wxDummyCSLocker##name // if there is only one thread, it is always the main one inline bool wxIsMainThread() { return true; } #endif // wxUSE_THREADS/!wxUSE_THREADS // mark part of code as being a critical section: this macro declares a // critical section with the given name and enters it immediately and leaves // it at the end of the current scope // // example: // // int Count() // { // static int s_counter = 0; // // wxCRITICAL_SECTION(counter); // // return ++s_counter; // } // // this function is MT-safe in presence of the threads but there is no // overhead when the library is compiled without threads #define wxCRITICAL_SECTION(name) \ wxCRIT_SECT_DECLARE(s_cs##name); \ wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name) // automatically lock GUI mutex in ctor and unlock it in dtor class WXDLLIMPEXP_BASE wxMutexGuiLocker { public: wxMutexGuiLocker() { wxMutexGuiEnter(); } ~wxMutexGuiLocker() { wxMutexGuiLeave(); } }; // ----------------------------------------------------------------------------- // implementation only until the end of file // ----------------------------------------------------------------------------- #if wxUSE_THREADS #if defined(__WINDOWS__) || defined(__OS2__) || defined(__EMX__) || defined(__DARWIN__) // unlock GUI if there are threads waiting for and lock it back when // there are no more of them - should be called periodically by the main // thread extern void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter(); // returns true if the main thread has GUI lock extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread(); // wakes up the main thread if it's sleeping inside ::GetMessage() extern void WXDLLIMPEXP_BASE wxWakeUpMainThread(); #ifndef __DARWIN__ // return true if the main thread is waiting for some other to terminate: // wxApp then should block all "dangerous" messages extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread(); #endif #endif // MSW, OS/2 #endif // wxUSE_THREADS #endif // _WX_THREAD_H_