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// -*- C++ -*-
//==========================================================================
/**
* @file Condition_T.h
*
* @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
*/
//==========================================================================
#ifndef ACE_CONDITION_T_H
#define ACE_CONDITION_T_H
#include /**/ "ace/pre.h"
#include "ace/OS_NS_Thread.h"
#include "ace/Condition_Attributes.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#if defined (ACE_HAS_THREADS) /* ACE platform supports some form of threading. */
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
class ACE_Time_Value;
/**
* @class ACE_Condition
*
* @brief 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 exclusion
* 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 <ACE_Condition> with
* @a ACE_Thread_Mutex, @a ACE_Recursive_Thread_Mutex, or @a ACE_Null_Mutex.
*/
template <class MUTEX>
class ACE_Condition
{
public:
/// Initialize the condition variable.
ACE_Condition (MUTEX &m, int type = USYNC_THREAD,
const ACE_TCHAR *name = 0, void *arg = 0);
/// Initialize the condition variable.
ACE_Condition (MUTEX &m,
const ACE_Condition_Attributes &attributes,
const ACE_TCHAR *name = 0,
void *arg = 0);
/// Implicitly destroy the condition variable.
~ACE_Condition ();
// = Lock accessors.
/**
* Block on condition, or until absolute time-of-day has passed. If
* @a abstime == 0 use "blocking" <wait> semantics. Else, if @a abstime
* != 0 and the call times out before the condition is signaled
* wait() returns -1 and sets errno to ETIME.
*/
int wait (const ACE_Time_Value *abstime);
/// Block on condition.
int wait ();
/**
* Block on condition or until absolute time-of-day has passed. If
* @a abstime == 0 use "blocking" wait() semantics on the @a mutex
* passed as a parameter (this is useful if you need to store the
* <Condition> in shared memory). Else, if @a abstime != 0 and the
* call times out before the condition is signaled wait() returns -1
* and sets errno to ETIME.
*/
int wait (MUTEX &mutex, const ACE_Time_Value *abstime = 0);
/// Signal one waiting thread.
int signal ();
/// Signal *all* waiting threads.
int broadcast ();
// = Utility methods.
/// Explicitly destroy the condition variable.
int remove ();
/// Returns a reference to the underlying mutex_;
MUTEX &mutex ();
/// Dump the state of an object.
void dump () const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
protected:
/// Condition variable.
ACE_cond_t cond_;
/// Reference to mutex lock.
MUTEX &mutex_;
private:
void operator= (const ACE_Condition<MUTEX> &) = delete;
ACE_Condition (const ACE_Condition<MUTEX> &) = delete;
};
/**
* @class ACE_Thread_Condition
*
* @brief ACE_Condition variable wrapper that works within processes.
*
* 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.
*/
template <class MUTEX>
class ACE_Thread_Condition : public ACE_Condition<MUTEX>
{
public:
ACE_Thread_Condition (MUTEX &m, const ACE_TCHAR *name = 0, void *arg = 0);
/// Dump the state of an object.
void dump () const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
};
ACE_END_VERSIONED_NAMESPACE_DECL
#if defined (__ACE_INLINE__)
#include "ace/Condition_T.inl"
#endif /* __ACE_INLINE__ */
#if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
#include "ace/Condition_T.cpp"
#endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
#if defined (ACE_TEMPLATES_REQUIRE_PRAGMA)
#pragma implementation ("Condition_T.cpp")
#endif /* ACE_TEMPLATES_REQUIRE_PRAGMA */
#endif /* ACE_HAS_THREADS */
#include /**/ "ace/post.h"
#endif /* ACE_CONDITION_T_H */
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