CPP, SINGLETON

支持并发的单例模式

单例模式是一个常用的编程范例，当我们希望程序中的某个实例最多只存在一个时，可以使用单例模式，下面是一个支持并发的单例模式的cpp代码示例：

#include <mutex>

class Singleton {
private:
    inline static Singleton* instance = nullptr;
    inline static std::mutex latch;

    Singleton() {
        // std::cout << " Singleton instance created." << std::endl;
    }

    Singleton(const Singleton&) = delete;
    Singleton& operator=(const Singleton&) = delete;

public:
    static Singleton* getInstance() {
        std::scoped_lock<std::mutex> lock{latch};
        if (instance == nullptr) {
            instance = new Singleton();
        }
        return instance;
    }

    void doSomething() {
        // std::cout << "Doing something." << std::endl;
    }

    static void releaseInstance() {
        if (instance != nullptr) {
            delete instance;
            instance = nullptr;
            // std::cout << " Singleton instance destroyed." << std::endl;
        }
    }
};