如何在对象切片时生成编译器警告/错误 [英] How to generate a compiler warning/error when object sliced

问题描述

我想知道是否可能让编译器针对代码发出警告/错误，如下所示：

注意： p>

1。是的，它是坏的编程风格，我们应该避免这种情况 - 但我们在处理遗留代码，希望编译器可以帮助我们识别这种情况。）

2。我喜欢使用编译器选项（VC ++）禁用或启用对象切片（如果有）。

  {}; 
 class Derived：public Base {}; 
 
 void Func（Base）
 {
 
} 
 
 // void Func（Derived）
 // {
 // 
 //} 
 
 // main 
 Func（Derived（））; 
 

在这里，如果我注释掉第二个函数，第一个函数将被调用 - 编译器VC ++和Gcc）感觉很舒服。

是C ++标准吗？并且我可以请求编译器（VC ++）在遇到这样的代码时给我一个警告。

感谢这么多!!!

编辑：

非常感谢您的帮助！

我找不到编译器选项给出错误/警告 - 我甚至发布在MSDN论坛为VC ++编译器顾问没有答案。所以我恐怕gcc和vc ++都没有实现这个特性。

所以添加构造函数，派生类作为参数是最好的解决方案。

编辑

我已经向MS提交了一个feedbak，希望他们尽快解决：

https：// connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=421579

-Baiyan

解决方案

如果你可以修改基类，你可以这样做：

  class Base 
 {
 public：
 //未实现将导致链接错误
 Base（const Derived& d）; 
 const Base& operator =（const Derived& rhs）; 
}; 
  

根据你的编译器，你应该得到翻译单元，也许切片发生的功能。

I want to know if it is possible to let compiler issue a warning/error for code as following:

Note:

1. Yea, it is bad programming style and we should avoid such cases - but we are dealing with legacy code and hope compiler can help identify such cases for us.)

2. I prefer a compiler option (VC++) to disable or enable object slicing, if there is any.

class Base{};
class Derived: public Base{};

void Func(Base)
{

}

//void Func(Derived)
//{
//
//}

//main
Func(Derived());

Here if I comment out the second function, the first function would be called - and the compiler (both VC++ and Gcc) feels comfortable with that.

Is it C++ standard? and can I ask compiler (VC++) to give me a warning when met such code?

Thanks so much!!!

Edit:

Thanks all so much for your help!

I can't find a compiler option to give a error/warning - I even posted this in MSDN forum for VC++ compiler consultant with no answer. So I am afraid neither gcc nor vc++ implemented this feature.

So add constructor which take derived classes as paramter would be the best solution for now.

Edit

I have submit a feedbak to MS and hope they will fix it soon:

https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=421579

-Baiyan

解决方案

If you can modify the base class you could do something like:

class Base
{
public:
// not implemented will cause a link error
    Base(const Derived &d);
    const Base &operator=(const Derived &rhs);
};

Depending on your compiler that should get you the translation unit, and maybe the function where the slicing is happening.

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