在C ++ 17或更高版本中的哪里初始化静态const成员? [英] Where to initialize static const member in c++17 or newer?

问题描述

问题是在C ++ 17或更高版本中在哪里初始化静态const成员?请考虑以下两种在c ++中初始化静态const成员的解决方案:

The questions is where to initialize static const member in c++17 or newer? Please consider the following two solutions for initializing a static const member in c++:

解决方案1(适用于c ++ 14或更早版本):

//foo.h:
#include <iostream>

struct foo{
    static const std::string ToBeInitialized;
};

//foo.cpp
#include <iostream>
#include "foo.h"

const std::string foo::ToBeInitialized{"with a value"};

解决方案2(适用于c ++ 17或更高版本):

//foo.h:
#include <iostream>
struct foo{
    inline static const std::string ToBeInitialized{"with a value"};
};

当前，我更喜欢解决方案2，因为它更短.使用解决方案1或解决方案2的优点和缺点是什么?

Currently I prefer solution 2 because it is shorter. What are the advantages and disadvanteges of using solution 1 or solution 2?

我很清楚以下事实:有关静态const初始化的几个问题:

I am well aware of the fact that there are several questions dealing about static const initialization:

• 如何在C ++中初始化静态const成员?

使用C ++在何处初始化静态const

静态const成员变量初始化

但是，以上所有问题均未明确处理c ++ 17或更高版本.

However non of the above questions deal with c++17 or newer explicitly.

推荐答案

据我了解，区别在于非内联"静态变量被编译为单个实例，而内联"变量被编译为单个实例.每个翻译单元将其编译为一个，然后由链接器消除为一个.这表示内联"消除只能在链接的代码内发生，它不能跨动态链接的代码.我相信此线程中已经提供了很好的解释内联静态const与静态const变量.祝你好运！

As I understand it the difference is that the "non-inline" static variable gets compiled to a single instance while the "inline" one gets compiled to one per translation unit and then eliminated to a single one by the linker. This means the "inline" elimination can occur only within the linked code, it can NOT cross dynamically linked code. I believe a good explanation has been provided in this thread Inline static const vs static const variable . Good luck!

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