- 变量警告 [英] -Wunused-variable warning

问题描述

我在学校作业中实现单例设计模式，这是我的类头文件：

I am implementing the singleton design pattern in a school assignment, and this is my class header file:

class Scheduler {
public:
    static Scheduler * instance();
    ~Scheduler();

private:
    Scheduler();
};

static Scheduler * _singleton = 0; // WARNING HERE

我的问题是我一直收到这个错误：

My problem is that I keep getting this error:

../Scheduler.h:60:20: warning: ‘_singleton’ defined but not used [-Wunused-variable]

我们必须提交没有编译警告的作业。如何摆脱这个警告？没有必要在头文件本身使用 _singleton ，所以我不知道该怎么办。我知道这很蠢，但还是...

And we have to submit assignments with no compilation warnings. How do I get rid of this warning? There's no need for me to use _singleton in the header file itself so I'm not sure what to do. I know it's stupid, but still...

想法？

推荐答案

p>您的静态单例实例指针应该是类成员。目前只是一个自由的指针。

Your static singleton instance pointer should be a class member. Currently it is just a free pointer.

class Scheduler {
// as before
private:
    Scheduler();
    static Scheduler* _singleton; // declare it in the class
};

并在实施文件中：

Scheduler * Scheduler::_singleton = 0;

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