C++中多线程Singleton的实现

最新推荐文章于 2024-08-22 21:57:00 发布

转载最新推荐文章于 2024-08-22 21:57:00 发布 · 398 阅读

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本文介绍了一种使用模板类实现单例模式的方法，并在此基础上展示了如何在多线程环境下确保线程安全。通过实例演示了在C++中如何利用互斥锁（pthread_mutex）来实现单例类的线程同步，确保了多个线程同时访问单例对象时的正确性和效率。

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from http://blog.chinaunix.net/xmlrpc.php?r=blog/article&id=4281275&uid=26611383
/**********************************************
******* g++ test.cpp -lpthread****************
* *******************************************/
#include <iostream>
#include <pthread.h>
using namespace std;
template <class T>
class Singleton
{
public:
Singleton()
{
}
static T* GetInstance()
{
if(m_pInstance == NULL)
{
pthread_mutex_lock(&mutex);
if(m_pInstance == NULL)
{
T* temp = new T;
m_pInstance = temp;
}
pthread_mutex_unlock(&mutex);
}
return m_pInstance;
}
private:
static T* m_pInstance;
static pthread_mutex_t mutex;
};
template<class T>
T* Singleton<T>::m_pInstance = NULL;
template<class T>
pthread_mutex_t Singleton<T>::mutex;
class Test:public Singleton<Test>
{
public:
Test()
{
cout<<"Test::Test()."<<endl;
}
};
void* thread1(void*)
{
cout<<"In thread1."<<endl;
Test* test1 = Test::GetInstance();
}
void* thread2(void *)
{
cout<<"In thread2."<<endl;
Test* test2 = Test::GetInstance();
}
int main()
{
const unsigned int thread_num = 20;
pthread_t thread_id[thread_num];
for(unsigned int i = 0; i<thread_num;i++)
{
pthread_create(&thread_id[i], NULL, thread1, NULL);
}
for(unsigned int i = 0; i<thread_num;i++)
{
pthread_create(&thread_id[i], NULL, thread2, NULL);
}
sleep(1);
return 0;
}