ACE_Condition< MUTEX > Class Template Reference

ACE_Condition variable wrapper, which allows threads to block until shared data changes state. More...

#include <Condition_T.h>

Inheritance diagram for ACE_Condition< MUTEX >:

[legend]Collaboration diagram for ACE_Condition< MUTEX >:

[legend]List of all members.

Public Member Functions
	ACE_Condition (MUTEX &m, int type=USYNC_THREAD, const ACE_TCHAR *name=0, void *arg=0)
	Initialize the condition variable.
	~ACE_Condition (void)
	Implicitly destroy the condition variable.
int	wait (const ACE_Time_Value *abstime)
int	wait (void)
	Block on condition.
int	wait (MUTEX &mutex, const ACE_Time_Value *abstime=0)
int	signal (void)
	Signal one waiting thread.
int	broadcast (void)
	Signal *all* waiting threads.
int	remove (void)
	Explicitly destroy the condition variable.
MUTEX &	mutex (void)
	Returns a reference to the underlying mutex_;.
void	dump (void) const
	Dump the state of an object.
Protected Attributes
ACE_cond_t	cond_
	Condition variable.
MUTEX &	mutex_
	Reference to mutex lock.
Private Member Functions
void	operator= (const ACE_Condition< MUTEX > &)
	ACE_Condition (const ACE_Condition< MUTEX > &)

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Detailed Description

template<class MUTEX>
class ACE_Condition< MUTEX >

ACE_Condition variable wrapper, which allows threads to block until shared data changes state.

A condition variable enables threads to atomically block and test the condition under the protection of a mutual exclu- sion lock (mutex) until the condition is satisfied. That is, the mutex must have been held by the thread before calling wait or signal on the condition. If the condition is false, a thread blocks on a condition variable and atomically releases the mutex that is waiting for the condition to change. If another thread changes the condition, it may wake up waiting threads by signaling the associated condition variable. The waiting threads, upon awakening, reacquire the mutex and re-evaluate the condition. Note, you can only parameterize with ACE_Thread_Mutex, ACE_Recursive_Thread_Mutex, or ACE_Null_Mutex.

Definition at line 54 of file Condition_T.h.

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Constructor & Destructor Documentation

template<class MUTEX> ACE_Condition< MUTEX >::ACE_Condition (  MUTEX &  m, int  type = USYNC_THREAD, const ACE_TCHAR *  name = 0, void *  arg = 0 )

Initialize the condition variable. Definition at line 56 of file Condition_T.cpp. References ACE_ERROR, ACE_LIB_TEXT, ACE_TCHAR, ACE_OS::cond_init(), and LM_ERROR. : mutex_ (m) { // ACE_TRACE ("ACE_Condition<MUTEX>::ACE_Condition"); if (ACE_OS::cond_init (&this->cond_, (short) type, name, arg) != 0) ACE_ERROR ((LM_ERROR, ACE_LIB_TEXT ("%p\n"), ACE_LIB_TEXT ("ACE_Condition::ACE_Condition"))); }

template<class MUTEX> ACE_Condition< MUTEX >::~ACE_Condition (  void   )

Implicitly destroy the condition variable. Definition at line 75 of file Condition_T.cpp. References ACE_ERROR, ACE_LIB_TEXT, LM_ERROR, and ACE_Condition< MUTEX >::remove(). { // ACE_TRACE ("ACE_Condition<MUTEX>::~ACE_Condition"); if (this->remove () == -1) ACE_ERROR ((LM_ERROR, ACE_LIB_TEXT ("%p\n"), ACE_LIB_TEXT ("ACE_Condition::~ACE_Condition"))); }

template<class MUTEX> ACE_Condition< MUTEX >::ACE_Condition (  const ACE_Condition< MUTEX > &   )  [private]

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Member Function Documentation

template<class MUTEX> ACE_INLINE int ACE_Condition< MUTEX >::broadcast (  void   )

Signal *all* waiting threads. Definition at line 45 of file Condition_T.inl. References ACE_OS::cond_broadcast(). { // ACE_TRACE ("ACE_Condition<MUTEX>::broadcast"); return ACE_OS::cond_broadcast (&this->cond_); }

template<class MUTEX> ACE_BEGIN_VERSIONED_NAMESPACE_DECL void ACE_Condition< MUTEX >::dump (  void   )  const

Dump the state of an object. Reimplemented in ACE_Thread_Condition< MUTEX >, and ACE_Thread_Condition< ACE_Thread_Mutex >. Definition at line 25 of file Condition_T.cpp. References ACE_BEGIN_DUMP, ACE_DEBUG, ACE_END_DUMP, ACE_LIB_TEXT, and LM_DEBUG. Referenced by ACE_Thread_Condition< MUTEX >::dump(). { #if defined (ACE_HAS_DUMP) // ACE_TRACE ("ACE_Condition<MUTEX>::dump"); ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this)); ACE_DEBUG ((LM_DEBUG, ACE_LIB_TEXT ("\n"))); ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP)); #endif /* ACE_HAS_DUMP */ }

template<class MUTEX> ACE_INLINE MUTEX & ACE_Condition< MUTEX >::mutex (  void   )

Returns a reference to the underlying mutex_;. Definition at line 31 of file Condition_T.inl. { // ACE_TRACE ("ACE_Condition<MUTEX>::mutex"); return this->mutex_; }

template<class MUTEX> void ACE_Condition< MUTEX >::operator= (  const ACE_Condition< MUTEX > &   )  [private]

template<class MUTEX> ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE int ACE_Condition< MUTEX >::remove (  void   )

Explicitly destroy the condition variable. Definition at line 8 of file Condition_T.inl. References ACE_OS::cond_broadcast(), ACE_OS::cond_destroy(), EBUSY, and ACE_OS::thr_yield(). Referenced by ACE_Condition< MUTEX >::~ACE_Condition(), and ACE_Condition< ACE_Recursive_Thread_Mutex >::~ACE_Condition(). { // ACE_TRACE ("ACE_Condition<MUTEX>::remove"); // cond_destroy() is called in a loop if the condition variable is // BUSY. This avoids a condition where a condition is signaled and // because of some timing problem, the thread that is to be signaled // has called the cond_wait routine after the signal call. Since // the condition signal is not queued in any way, deadlock occurs. int result = 0; while ((result = ACE_OS::cond_destroy (&this->cond_)) == -1 && errno == EBUSY) { ACE_OS::cond_broadcast (&this->cond_); ACE_OS::thr_yield (); } return result; }

template<class MUTEX> ACE_INLINE int ACE_Condition< MUTEX >::signal (  void   )

Signal one waiting thread. Definition at line 38 of file Condition_T.inl. References ACE_OS::cond_signal(). { // ACE_TRACE ("ACE_Condition<MUTEX>::signal"); return ACE_OS::cond_signal (&this->cond_); }

template<class MUTEX> int ACE_Condition< MUTEX >::wait (  MUTEX &  mutex, const ACE_Time_Value *  abstime = 0 )

Block on condition or until absolute time-of-day has passed. If abstime == 0 use "blocking" wait() semantics on the passed as a parameter (this is useful if you need to store the in shared memory). Else, if != 0 and the call times out before the condition is signaled returns -1 and sets errno to ETIME. Definition at line 94 of file Condition_T.cpp. References ACE_OS::cond_timedwait(), and ACE_Condition< MUTEX >::wait(). { // ACE_TRACE ("ACE_Condition<MUTEX>::wait"); if (abstime == 0) return this->wait (); else { return ACE_OS::cond_timedwait (&this->cond_, &mutex.lock_, (ACE_Time_Value *) abstime); } }

template<class MUTEX> int ACE_Condition< MUTEX >::wait (  void   )

Block on condition. Definition at line 86 of file Condition_T.cpp. References ACE_OS::cond_wait(). Referenced by ACE_Condition< MUTEX >::wait(), and ACE_Condition< ACE_Recursive_Thread_Mutex >::wait(). { // ACE_TRACE ("ACE_Condition<MUTEX>::wait"); return ACE_OS::cond_wait (&this->cond_, &this->mutex_.lock_); }

template<class MUTEX> int ACE_Condition< MUTEX >::wait (  const ACE_Time_Value *  abstime  )

Block on condition, or until absolute time-of-day has passed. If abstime == 0 use "blocking" semantics. Else, if != 0 and the call times out before the condition is signaled returns -1 and sets errno to ETIME. Definition at line 113 of file Condition_T.cpp. References ACE_Condition< MUTEX >::wait(). { // ACE_TRACE ("ACE_Condition<MUTEX>::wait"); return this->wait (this->mutex_, abstime); }

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Member Data Documentation

template<class MUTEX> ACE_cond_t ACE_Condition< MUTEX >::cond_ [protected]

Condition variable. Definition at line 108 of file Condition_T.h.

template<class MUTEX> MUTEX& ACE_Condition< MUTEX >::mutex_ [protected]

Reference to mutex lock. Definition at line 111 of file Condition_T.h.

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The documentation for this class was generated from the following files:

• Condition_T.h
• Condition_T.cpp
• Condition_T.inl

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