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critical section
- To: win32-pthread <pthreads-win32 at sourceware dot cygnus dot com>
- Subject: critical section
- From: "Ye Liu" <yliu at tibco dot com>
- Date: Tue, 31 Jul 2001 14:27:59 -0700
- Organization: Tibco Software
Greets,
When I impelement the critical section using mutex, I have the following
code:
/* TIBMutex.h */
#ifndef _TIBMutex_H_
#define _TIBMutex_H_
class TIBMutex
{
public:
TIBMutex();
~TIBMutex();
void acquire();
void acquire_yield();
void release();
int tryacquire();
private:
pthread_mutex_t m_Mutex;
pthread_mutexattr_t m_MutexAttr;
void init_MutexAttr();
int m_Count;
};
/* TIBMutex.cpp */
TIBMutex::TIBMutex()
{
m_Count = 0;
if (pthread_mutex_init(&m_Mutex, &m_MutexAttr))
/* error handling...*/
}
inline void TIBMutex::acquire()
{
while (m_Count);
if (pthread_mutex_lock(&m_Mutex))
{
/* error handling...*/
}
++m_Count;
return;
}
inline void TIBMutex::release()
{
if (pthread_mutex_unlock(&m_Mutex))
{
/* error handling...*/
}
--m_Count;
}
My questions are:
1. Do I need use a condition variable here because I use m_Count as 0/1
signal?
2. In the acquire(), when m_Count is not 0, the waiting thread should
"spin" there as the above or yield like the following acquire_yield()
inline void TIBMutex::acquire_yield()
{
while (m_Count)
shed_yield();
if (pthread_mutex_lock(&m_Mutex))
{
/* error handling...*/
}
++m_Count;
return;
}
--
Ye Liu
Tel(O) 650-846-5228