我可以在C ++的运行时初始化一个静态const成员吗？ [英] Can I initialize a static const member at run-time in C++?

问题描述

是否可以在运行时初始化我的类的静态const成员？这个变量在我的程序中是一个常量，但我想把它作为一个命令行参数发送。

Is it possible to initialize a static const member of my class during run-time? This variable is a constant throughout my program but I want to send it as a command-line argument.

//A.h
class A {
public: 
    static const int T;
};

//in main method
int main(int argc,char** argv)
{
    //how can I do something like 
    A::T = atoi(argv[1]);
}

如果不能这样做，我应该使用什么类型的变量？我需要在运行时初始化它，以及保留常量属性。

If this cannot be done, what is the type of variable I should use? I need to initialize it at run-time as well as preserve the constant property.

推荐答案

很抱歉，不同意评论和回答说，不可能有 const 符号在程序启动时而不是在编译时初始化。

I am sorry to disagree with the comments and answers saying that it is not possible for a static const symbol to be initialized at program startup rather than at compile time.

实际上这是可能的，我使用了很多次，从配置文件初始化它。类似：

Actually this IS possible, and I used it many times, BUT I initialize it from a configuration file. Something like:

// GetConfig is a function that fetches values from a configuration file
const int Param1 = GetConfig("Param1");
const int MyClass::Member1 = GetConfig("MyClass.Member1");

正如你所看到的，这些静态const在编译时不一定是已知的。

As you see, these static consts are not necessarily known at compile time. They can be set from the environment, such as a config file.

另一方面，如果可行的话，从argv []中设置它们似乎非常困难，因为当main（）启动时，静态符号已经初始化。

On the other hand, setting them from argv[], seems very difficult, if ever feasible, because when main() starts, static symbols are already initialized.

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