linux c语言读写锁,读写锁(Read-Write Lock)的一种实现

项目中用到了此类，实现了多个线程读、单个线程写的功能，基于Windows平台。

思想：两个相关的锁，一个用于读，一个用于写。可以多个同时读，但只能一个写。比传统的互斥锁，提高了一定的并发性。

#ifndef READER_WRITER_LOCK_H_

#define READER_WRITER_LOCK_H_

/*************************************************************

/* Multi-reader Single-writer class

/* author: http://vcsky.net 2011/05/18

/* author: http://www.it165.net 2011/05/18

**************************************************************/

#include "windows.h"

class CReaderWriterLock

{

public:

CReaderWriterLock()

{

m_Readers = 0;

InitializeCriticalSection(&m_Writer);

InitializeCriticalSection(&m_ReaderCount);

m_ClearReadersEvent = CreateEvent(NULL,TRUE,TRUE,NULL);

}

~CReaderWriterLock()

{

WaitForSingleObject(m_ClearReadersEvent,INFINITE);

CloseHandle(m_ClearReadersEvent);

DeleteCriticalSection(&m_Writer);

DeleteCriticalSection(&m_ReaderCount);

}

/*Read, reset events */

void EnterReader(void)

{

EnterCriticalSection(&m_Writer);

EnterCriticalSection(&m_ReaderCount);

if (++m_Readers == 1)

{

::ResetEvent(m_ClearReadersEvent);

}

LeaveCriticalSection(&m_ReaderCount);

LeaveCriticalSection(&m_Writer);

}

/*leave read, triggered events */

void LeaveReader(void)

{

EnterCriticalSection(&m_ReaderCount);

if (--m_Readers == 0)

{

::SetEvent(m_ClearReadersEvent);

}

LeaveCriticalSection(&m_ReaderCount);

}

/*Only after reading, to be able to write*/

void EnterWriter(void)

{

EnterCriticalSection(&m_Writer);

WaitForSingleObject(m_ClearReadersEvent,INFINITE);

}

void LeaveWriter(void)

{

LeaveCriticalSection(&m_Writer);

}

private:

CRITICAL_SECTION m_Writer;

CRITICAL_SECTION m_ReaderCount;

int m_Readers;

HANDLE m_ClearReadersEvent;

};

#endif