可以调用成员初始值设定项列表中的函数吗？

发布于 2024-10-02 18:47:01 字数 377 浏览 4 评论 0原文

我的直觉是不是。我处于以下情况：

class PluginLoader
{
   public:
      Builder* const p_Builder;
      Logger* const p_Logger;

      //Others
};

PluginLoader::PluginLoader(Builder* const pBuilder)
   :p_Builder(pBuilder), p_Logger(pBuilder->GetLogger())
{
   //Stuff
}

或者我应该更改构造函数并从构造 PluginLoader 的位置传递一个 Logger* const ？

原文

My gut feeling is it is not. I am in the following situation:

class PluginLoader
{
   public:
      Builder* const p_Builder;
      Logger* const p_Logger;

      //Others
};

PluginLoader::PluginLoader(Builder* const pBuilder)
   :p_Builder(pBuilder), p_Logger(pBuilder->GetLogger())
{
   //Stuff
}

Or should I change the constructor and pass a Logger* const from where PluginLoader is constructed?

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°如果伤别离去 2024-10-09 18:47:01

这是完全正常的。 p_Builder 在它之前被初始化。

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一袭白衣梦中忆 2024-10-09 18:47:01

你拥有的很好。但是，我只是想警告您要小心不要这样做：（GMan 提到了这一点，我只是想让它完全清楚）

class PluginLoader
{
   public:
      Logger* const p_Logger;   // p_Logger is listed first before p_Builder
      Builder* const p_Builder;

      //Others
};

PluginLoader::PluginLoader(Builder* const pBuilder)
   :p_Builder(pBuilder),
    p_Logger(p_Builder->GetLogger())   // Though listed 2nd, it is called first.
                                       // This wouldn't be a problem if pBuilder 
                                       // was used instead of p_Builder
{
   //Stuff
}

请注意，我对您的代码做了 2 处更改。首先，在类定义中，我在 p_Builder 之前声明了 p_Logger。其次，我使用成员 p_Builder 来初始化 p_Logger，而不是参数。

这些更改中的任何一个都可以，但是它们一起引入了一个错误，因为 p_Logger 首先被初始化，并且您使用未初始化的 p_Builder 来初始化它。

请始终记住，成员按照它们在类定义中出现的顺序进行初始化。并且将它们放入初始化列表中的顺序无关紧要。

What you have is fine. However, I just want to warn you to be careful not to do this: (GMan alluded to this, I just wanted to make it perfectly clear)

class PluginLoader
{
   public:
      Logger* const p_Logger;   // p_Logger is listed first before p_Builder
      Builder* const p_Builder;

      //Others
};

PluginLoader::PluginLoader(Builder* const pBuilder)
   :p_Builder(pBuilder),
    p_Logger(p_Builder->GetLogger())   // Though listed 2nd, it is called first.
                                       // This wouldn't be a problem if pBuilder 
                                       // was used instead of p_Builder
{
   //Stuff
}

Note that I made 2 changes to your code. First, in the class definition, I declared p_Logger before p_Builder. Second, I used the member p_Builder to initialize p_Logger, instead of the parameter.

Either one of these changes would be fine, but together they introduce a bug, because p_Logger is initialized first, and you use the uninitialized p_Builder to initialize it.

Just always remember that the members are initialized in the order they appear in the class definition. And the order you put them in your initialization list is irrelevant.

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