C ++：隐藏规则背后的原理 [英] C++: rationale behind hiding rule

问题描述

在C ++中隐藏规则的理由是什么？

What's the rationale behind the hiding rule in C++?

class A { void f(int); }
class B : public A { void f(double); } // B::f(int) is hidden

• 如果这是一个有意义的功能，我认为应该也可以隐藏函数，而不定义相同名称的新函数：类似这样：

  • If it is a meaningful feature I think it should also be possible to hide functions without defining new functions with the same name: something like this:

    class B : public A { hide void f(double); }
    

    但这是不可能的。

    我不认为它简化了编译器的工作，因为编译器必须能够取消隐藏函数，当你明确使用使用 ：

    I don't think it simplifies compilers job, since compilers must anyway be able to unhide functions when you explicitly use the using directive:

    class B : public A { using A::f; void f(double); } // B::f(int) NOT hidden
    

  
  

  那么，如何有一个隐藏规则呢？

  So, how come there is a hiding rule?

  哼，所有三个答案似乎都很好，并显示隐藏规则的不同理由。我不知道应该接受哪个答案。

  Hum, all the three answers seem to be good, and show different rationales for the hiding rule. I'm not sure about which answer I should accept.

  推荐答案

  这是一个毛茸茸的问题，但显然的想法是，功能有助于避免在更改基类时发生微妙的错误（否则可能会偷取之前被派生类处理的调用）。基类的变化可以影响派生类的编译结果，所以我不认为我理解100％的解释。

  It's an hairy question, but apparently the idea is that this hiding feature helps avoiding subtle bugs when making changes to a base class (that could otherwise "steal" calls that before would have been handled by the derived class). Still a change in a base class can influence the result of compilation of derived classes so I don't think I understand 100% this explanation.

  我同意这个主题是所以经常讨论，可能隐藏实际上增加了C ++程序员的惊喜的数量。

  I agree that this topic is so frequently discussed that probably the hiding actually increases the amount of "surprises" in C++ programmers.

  有关这个问题的详细讨论可以找到在这里 ...

  A detailed discussion about this issue can be found here...

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