设计模式 《Head First》（五）－－单件模式（Singleton Pattern）

废话不说，直接上代码

class Singleton
{
public:
    Singleton* getInstance()
    {
        if (mpInstance == NULL)
        {
            lock();
            if (mpInstance == NULL)
                mpInstance = new Singleton;
            unlock();
        }
        return mpInstance;
    }
private:
    Singleton() {}
    static Singleton* mpSingleton;
};