快问.无论如何都要继承单例,以便子类是单例吗？我已经四处寻找,但我能找到的每一个单身都是按照课程实现的,而不是通用的.
解决方法
是的,有一种通用的方式.您可以通过
CRTP实现Singleton,例如：
template<typename T>
class Singleton
{
protected:
Singleton() noexcept = default;
Singleton(const Singleton&) = delete;
Singleton& operator=(const Singleton&) = delete;
virtual ~Singleton() = default; // to silence base class Singleton<T> has a
// non-virtual destructor [-Weffc++]
public:
static T& get_instance() noexcept(std::is_nothrow_constructible<T>::value)
{
// Guaranteed to be destroyed.
// Instantiated on first use.
// Thread safe in C++11
static T instance;
return instance;
}
};
然后从中得出让你的孩子成为单身人士：
class MySingleton: public Singleton<MySingleton>
{
// needs to be friend in order to
// access the private constructor/destructor
friend class Singleton<MySingleton>;
public:
// Declare all public members here
private:
MySingleton()
{
// Implement the constructor here
}
~MySingleton()
{
// Implement the destructor here
}
};
