线程安全 单例模式

class Sigleton
{
public:
	static Sigleton *GetInstance()
	{
		if (NULL == pInstance)
		{
			pthread_mutex_lock(&pMutex);
			if (NULL == pInstance)
			{
				pInstance = new Sigleton;
			}
			pthread_mutex_unlock(&pMutex);
		}
		return pInstance;
	}
	static void ReleaseInstance()
	{
		if (NULL != pInstance)
		{
			pthread_mutex_lock(&pMutex);
			if (NULL != pInstance)
			{
				delete pInstance;
				pInstance = NULL;
			}
			pthread_mutex_unlock(&pMutex);
		}
	}
private:
	Sigleton();
	Sigleton(const Sigleton&);
	Sigleton& operator=(const Sigleton&);
	static Sigleton *pInstance;
	static pthread_mutex_t pMutex; //= PTHREAD_MUTEX_INITIALIZER;
	 class CGarbo
	{
	public:
		CGarbo()	{}
		~CGarbo()
		{
			if (NULL != pInstance)
			{
				pthread_mutex_lock(&pMutex);
				if (NULL != pInstance)
				{
					delete pInstance;
					pInstance = NULL;
				}
				pthread_mutex_unlock(&pMutex);
			}
			if (NULL != pMutex)
			{
				pthread_mutex_destory(&pMutex);
			}
		}
	};
	static CGarbo mGarbo;
};