Linux平台上用C++实现多线程互斥锁

转：http://blog.csdn.net/chexlong/article/details/7058283

在上篇用C++实现了Win32平台上的多线程互斥锁，这次写个Linux平台上的，同样参考了开源项目C++ Sockets的代码，在此对这些给开源项目做出贡献的斗士们表示感谢！

    下边分别是互斥锁类和测试代码，已经在Fedora 13虚拟机上测试通过。

Lock.h

#ifndef _Lock_H
#define _Lock_H

#include <pthread.h>

//锁接口类
class ILock
{
public:
    virtual ~ILock() {}

    virtual void Lock() const = 0;
    virtual void Unlock() const = 0;
};

//互斥锁类
class CMutex : public ILock
{
public:
    CMutex();
    ~CMutex();

    virtual void Lock() const;
    virtual void Unlock() const;

private:
    mutable pthread_mutex_t m_mutex;
};

//锁
class CMyLock
{
public:
    CMyLock(const ILock&);
    ~CMyLock();

private:
    const ILock& m_lock;
};


#endif

#ifndef _Lock_H #define _Lock_H #include <pthread.h> //锁接口类 class ILock { public: virtual ~ILock() {} virtual void Lock() const = 0; virtual void Unlock() const = 0; }; //互斥锁类 class CMutex : public ILock { public: CMutex(); ~CMutex(); virtual void Lock() const; virtual void Unlock() const; private: mutable pthread_mutex_t m_mutex; }; //锁 class CMyLock { public: CMyLock(const ILock&); ~CMyLock(); private: const ILock& m_lock; }; #endif

Lock.cpp

#include "Lock.h"


//动态方式初始化互斥锁
CMutex::CMutex()
{
    pthread_mutex_init(&m_mutex, NULL);
}

//注销互斥锁
CMutex::~CMutex()
{
    pthread_mutex_destroy(&m_mutex);
}

//确保拥有互斥锁的线程对被保护资源的独自访问
void CMutex::Lock() const
{
    pthread_mutex_lock(&m_mutex);
}

//释放当前线程拥有的锁，以使其它线程可以拥有互斥锁，对被保护资源进行访问
void CMutex::Unlock() const
{
    pthread_mutex_unlock(&m_mutex);
}

//利用C++特性，进行自动加锁
CMyLock::CMyLock(const ILock& m) : m_lock(m)
{
    m_lock.Lock();
}

//利用C++特性，进行自动解锁
CMyLock::~CMyLock()
{
    m_lock.Unlock();
}

#include "Lock.h" //动态方式初始化互斥锁 CMutex::CMutex() { pthread_mutex_init(&m_mutex, NULL); } //注销互斥锁 CMutex::~CMutex() { pthread_mutex_destroy(&m_mutex); } //确保拥有互斥锁的线程对被保护资源的独自访问 void CMutex::Lock() const { pthread_mutex_lock(&m_mutex); } //释放当前线程拥有的锁，以使其它线程可以拥有互斥锁，对被保护资源进行访问 void CMutex::Unlock() const { pthread_mutex_unlock(&m_mutex); } //利用C++特性，进行自动加锁 CMyLock::CMyLock(const ILock& m) : m_lock(m) { m_lock.Lock(); } //利用C++特性，进行自动解锁 CMyLock::~CMyLock() { m_lock.Unlock(); }

 

    测试代码

// pthread_mutex.cpp : 定义控制台应用程序的入口点。
//

#include <iostream>
#include <unistd.h>
#include "Lock.h"

using namespace std;

//创建一个互斥锁
CMutex g_Lock;


//线程函数
void * StartThread(void *pParam)
{
    char *pMsg = (char *)pParam;
    if (!pMsg)
    {
        return (void *)1;
    }

    //对被保护资源（以下打印语句）自动加锁
    //线程函数结束前，自动解锁
    CMyLock lock(g_Lock);

    for( int i = 0; i < 5; i++ )
    {
        cout << pMsg << endl;
        sleep( 1 );
    }

    return (void *)0;
}

int main(int argc, char* argv[])
{
    pthread_t thread1,thread2;
    pthread_attr_t attr1,attr2;

    char *pMsg1 = "First print thread.";
    char *pMsg2 = "Second print thread.";

    //创建两个工作线程，分别打印不同的消息
    pthread_attr_init(&attr1);
    pthread_attr_setdetachstate(&attr1,PTHREAD_CREATE_JOINABLE);
    if (pthread_create(&thread1,&attr1, StartThread,pMsg1) == -1)
    {
        cout<<"Thread 1: create failed"<<endl;
    }
    pthread_attr_init(&attr2);
    pthread_attr_setdetachstate(&attr2,PTHREAD_CREATE_JOINABLE);
    if (pthread_create(&thread2,&attr2, StartThread,pMsg2) == -1)
    {
        cout<<"Thread 2: create failed"<<endl;
    }

    //等待线程结束
    void *result;
    pthread_join(thread1,&result);
    pthread_join(thread2,&result);

    //关闭线程，释放资源
    pthread_attr_destroy(&attr1);
    pthread_attr_destroy(&attr2);

    int iWait;
    cin>>iWait;

    return 0;
}

// pthread_mutex.cpp : 定义控制台应用程序的入口点。 // #include <iostream> #include <unistd.h> #include "Lock.h" using namespace std; //创建一个互斥锁 CMutex g_Lock; //线程函数 void * StartThread(void *pParam) { char *pMsg = (char *)pParam; if (!pMsg) { return (void *)1; } //对被保护资源（以下打印语句）自动加锁 //线程函数结束前，自动解锁 CMyLock lock(g_Lock); for( int i = 0; i < 5; i++ ) { cout << pMsg << endl; sleep( 1 ); } return (void *)0; } int main(int argc, char* argv[]) { pthread_t thread1,thread2; pthread_attr_t attr1,attr2; char *pMsg1 = "First print thread."; char *pMsg2 = "Second print thread."; //创建两个工作线程，分别打印不同的消息 pthread_attr_init(&attr1); pthread_attr_setdetachstate(&attr1,PTHREAD_CREATE_JOINABLE); if (pthread_create(&thread1,&attr1, StartThread,pMsg1) == -1) { cout<<"Thread 1: create failed"<<endl; } pthread_attr_init(&attr2); pthread_attr_setdetachstate(&attr2,PTHREAD_CREATE_JOINABLE); if (pthread_create(&thread2,&attr2, StartThread,pMsg2) == -1) { cout<<"Thread 2: create failed"<<endl; } //等待线程结束 void *result; pthread_join(thread1,&result); pthread_join(thread2,&result); //关闭线程，释放资源 pthread_attr_destroy(&attr1); pthread_attr_destroy(&attr2); int iWait; cin>>iWait; return 0; }

 

    编译成功后，运行程序

    同样，若将下边代码注释掉，重新编译

//CMyLock lock(g_Lock);

//CMyLock lock(g_Lock);

    运行程序

    结果显而易见。