Re: conditions for automatic generation of default ctor, copy ctor, and default assignment operator (operator)

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++

Date:

Tue, 15 Apr 2008 07:56:15 -0400

Message-ID:

<2008041507561516807-pete@versatilecodingcom>

On 2008-04-15 05:18:40 -0400, James Kanze <james.kanze@gmail.com> said:

On Apr 14, 6:16 pm, puzzlecracker <ironsel2...@gmail.com> wrote:

From my understanding, if you declare any sort of
constructors, (excluding copy ctor), the default will not be
included by default. Is this correct?

No. Any user defined constructor, including a copy constructor,
inhibits automatic generation of the default constructor.

Longer term, i.e. when C++0x is finalized, the solution to this problem
will be to tell the compiler to generate the default constructor
despite the existence of other constructors.

struct foo {
foo() = default;
foo(const foo&);
};

You'll also be able to tell the compiler not to generate a default constructor:

struct foo {
foo() = delete;
};

These modifiers will be applicable to all of the special member functions.

And before anyone asks: I don't know whether any compiler currently
implements this.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)