1??static Singleton?（ Meyers Singleton）
class Singleton {
public:
static Singleton& Instance() {
? static Singleton theSingleton;
? return theSingleton;
}
/* more (non-static) functions here */
private:
Singleton(); // ctor hidden
Singleton(Singleton const&); // copy ctor hidden
Singleton& operator=(Singleton const&); // assign op. hidden
~Singleton(); // dtor hidden
};
2 call_once
Singleton* Singleton::m_instance;
Singleton* Singleton::getInstance() {
? ? static std::once_flag oc;//用于call_once的局部靜態(tài)變量
? ? std::call_once(oc, [&] {? m_instance = new Singleton();});
? ? return m_instance;
}
https://blog.csdn.net/10km/article/details/49777749
