如何在仅标题库中拥有静态数据成员？ [英] How to have static data members in a header-only library?

问题描述

在非模板化库类中有一个静态成员的最好方法是
，而不会给类用户定义成员的负担？

说我想要提供这个类：

  class i_want_a_static_member 
 {
 static expensive_resource static_resource_; 
 
 public：
 void foo（）
 {
 static_resource_.bar（）; 
} 
}; 
  

然后类的用户不能忘记定义静态成员
已回答 许多 times ）：

  //这必须在翻译单元中的某处
 expensive_resource i_want_a_static_member :: static_resource_; 
  

我有一个答案，但它有一些缺点。是否有更好和/或更优雅的解决方案？

解决方案

可以使用函数局部静态变量。

  struct Foo {
 static int& Bar（）{static int I;返回I; } 
}; / / pre> 
What is the best way to have a static member in a non-templated library class,
without placing the burden of defining the member on the class user?

Say I want to provide this class:
class i_want_a_static_member
{
    static expensive_resource static_resource_;

public:
    void foo()
    {
        static_resource_.bar();
    }
};
Then the user of the class must not forget to define the static member somewhere
(as already answered many times):
// this must be done somewhere in a translation unit
expensive_resource i_want_a_static_member::static_resource_;
I do have an answer below, but it has some disadvantages. Are there better and/or more elegant solutions?
解决方案
You can use function local static variables.
struct Foo {
     static int& Bar() { static int I; return I; }
}; //                    ^~~~~~~~~~~~


                        
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