析构函数不应使用指针来声明吗？在 C++

发布于 2024-12-03 07:48:25 字数 476 浏览 0 评论 0原文

在 C++0x -n3290 草案中：他们在 :Destructors: 12.4/2nd 点最后一行中添加了

          **A destructor shall not be declared with a ref-qualifier.**

在 c++03 草案中....他们没有在析构函数中提到这一点？

我的问题是是否

   *~S() ;   //this declaration is allowed or not according to the Standard's
   //**~S(); ***~S() ; etc...........

允许这种类型的声明？他在草案中没有描述这个……声明？

在 GCC 4.6.0,Sun/Oracle C++12.0 中，--->允许此声明 int Comeau C/C++ -->不允许

原文

In C++0x -n3290 Draft : they added in section :Destructors : 12.4/2nd point last line

          **A destructor shall not be declared with a ref-qualifier.**

In c++03 Draft .... they didn't mention this point in destructors ?

my question is whether

   *~S() ;   //this declaration is allowed or not according to the Standard's
   //**~S(); ***~S() ; etc...........

this type of declaration is allowed ?
No where in the Draft he described about this ...Declaration?

In GCC 4.6.0,Sun/Oracle C++12.0 , --->this declaration is allowed
int Comeau C/C++ -->not allowed

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掐死时间 2024-12-10 07:48:25

这看起来不像是任何类型的合法函数声明，更不用说析构函数了。我不确定标准的这一部分在谈论什么，但我有一个猜测。

我怀疑有一个限定符表示您的函数正在右值引用上调用。像这样的事情：

class A {
 public:
   void IAmAnRValue() &&;
};

我认为标准中的语言是说析构函数上不允许使用此限定符，就像尾随 const 也是非法的一样。

而且，经过进一步的调查，我对自己的猜测的正确性的确信度大大提高了。理由如下：

将移动语义扩展为 *这个。

其中明确指出，函数现在可以在“cv-qualifer”之后有一个“ref-qualifier”。这意味着函数声明现在可以后跟 const & 或 const volatile && 而不仅仅是 const。使用的术语（引用限定符）与您引用的标准中使用的术语相同。析构函数不能拥有析构函数是有道理的。

That doesn't look like it would ever be a legal function declaration of any kind, much less for a destructor. I'm not positive what that part of the standard is talking about, but I have a guess.

I suspect there is a qualifier saying that your function is being called on an rvalue reference. Something like this:

class A {
 public:
   void IAmAnRValue() &&;
};

I think the language in the standard is saying that this qualifier is not allowed on a destructor, much like having a trailing const would also be illegal.

And, on further investigation, my certainty of the correctness of my surmise goes up considerably. Here is the justification:

Extending Move Semantics to *this.

There it clearly states that functions may now have a 'ref-qualifier' after the 'cv-qualifer'. This means that a function declaration may now be followed by const & or const volatile && instead of just const. And the term used (ref-qualifier) is the same as the term used in the little bit of the standard you're quoting. And it makes sense for destructors to not be able to have one.

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打小就很酷 2024-12-10 07:48:25

您误解了新标准中ref-qualifier的含义。就像您可以为 C++03 中的任何成员函数提供 const 限定符一样，您也可以为 C+ 中的成员函数添加 ref-qualifier +0x。该修饰符将影响函数隐式 this 参数的类型：

struct test {
   void f() const &&;  // implicit "this" in "f" is of type "test const &&"
};

就像析构函数不能是 static 或 const 一样，或 C++03 中的 const volatile，它不能采用引用限定符（& 或 &&) 在 C++0x 中。当然，以前的标准中不存在这一点。

You have misunderstood what ref-qualifier means in the new standard. In the same way that you can provide a const qualifier to any member function in C++03, you can also add a ref-qualifier to a member function in C++0x. That modifier will affect the type of the implicit this argument to the function:

struct test {
   void f() const &&;  // implicit "this" in "f" is of type "test const &&"
};

In the same way that a destructor cannot be static, or const, or const volatile in C++03, it cannot take a ref-qualifier (& or &&) in C++0x. Of course this bit was not present in the former standard.

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