A destructor Shall OR shall not be declared with a pointer ? in C++

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 decl开发者_如何学编程aration 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

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.

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.

The rule you are looking for is stated in the same paragraph, 12.4p2

A destructor takes no parameters, and no return type can be specified for it (not even void).

The phrase "no return type can be specified for it" also forbids "*", which is not immediately clear but can be seen by comparison with 12.3.2p1 (compare with this issue report):

... Such functions are called conversion functions. No return type can be specified.

That rule is what makes implementations forbid * operator int() { }. You can also argue with 12.4p1, although as that's phrased very general and is the first statement in the destructors section, I think the other statement above should be the primary argument

A special declarator syntax using an optional function-specifier (7.1.2) followed by ˜ followed by the destructor's class name followed by an empty parameter list is used to declare the destructor in a class definition.

As can be seen/read there is no mention of declarators such as * in that description, which shows the intent of the authors.