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// -*- C++ -*-
//==========================================================================
/**
* @file Condition_Thread_Mutex.h
*
* Moved from Synch.h.
*
* @author Douglas C. Schmidt <d.schmidt@vanderbilt.edu>
*/
//==========================================================================
#ifndef ACE_CONDITION_THREAD_MUTEX_H
#define ACE_CONDITION_THREAD_MUTEX_H
#include /**/ "ace/pre.h"
#include /**/ "ace/ACE_export.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#if !defined (ACE_HAS_THREADS)
# include "ace/Null_Condition.h"
#else /* ACE_HAS_THREADS */
// ACE platform supports some form of threading.
#include "ace/Thread_Mutex.h"
#include "ace/Condition_Attributes.h"
#include "ace/Condition_T.h"
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
class ACE_Time_Value;
/**
* @brief ACE_Condition template specialization written using
* ACE_Mutexes. This 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.
*/
template <>
class ACE_Export ACE_Condition<ACE_Thread_Mutex>
{
public:
/// Initialize the condition variable.
ACE_Condition (ACE_Thread_Mutex &m,
const ACE_TCHAR *name = 0,
void *arg = 0);
/// Initialize the condition variable.
ACE_Condition (ACE_Thread_Mutex &m,
const ACE_Condition_Attributes &attributes,
const ACE_TCHAR *name = 0,
void *arg = 0);
/// Implicitly destroy the condition variable.
~ACE_Condition ();
/**
* Explicitly destroy the condition variable. Note that only one
* thread should call this method since it doesn't protect against
* race conditions.
*/
int remove ();
/**
* Block on condition, or until absolute time-of-day has passed. If
* 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
* 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 (ACE_Thread_Mutex &mutex, const ACE_Time_Value *abstime = 0);
/// Signal one waiting thread.
int signal ();
/// Signal *all* waiting threads.
int broadcast ();
/// Returns a reference to the underlying mutex;
ACE_Thread_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.
ACE_Thread_Mutex &mutex_;
/// Keeps track of whether remove() has been called yet to avoid
/// multiple remove() calls, e.g., explicitly and implicitly in the
/// destructor. This flag isn't protected by a lock, so make sure
/// that you don't have multiple threads simultaneously calling
/// remove() on the same object, which is a bad idea anyway...
bool removed_;
private:
// = Prevent assignment and initialization.
void operator= (const ACE_Condition<ACE_Thread_Mutex> &);
ACE_Condition (const ACE_Condition<ACE_Thread_Mutex> &);
};
typedef ACE_Condition<ACE_Thread_Mutex> ACE_Condition_Thread_Mutex;
ACE_END_VERSIONED_NAMESPACE_DECL
#if defined (__ACE_INLINE__)
#include "ace/Condition_Thread_Mutex.inl"
#endif /* __ACE_INLINE__ */
#endif /* !ACE_HAS_THREADS */
#include /**/ "ace/post.h"
#endif /* ACE_CONDITION_THREAD_MUTEX_H */
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