Re: A Sample auto_ptr implementation

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Sun, 19 Oct 2008 09:22:14 -0700 (PDT)
Message-ID:
<f1c07b4b-ba68-4f5a-a0ee-9b7236eb30af@l42g2000hsc.googlegroups.com>
On Oct 13, 2:58 pm, Kai-Uwe Bux <jkherci...@gmx.net> wrote:

Yakov Gerlovin wrote:

Try to define assignment operator without template U
parameter:

//assignment operator
MyAutoPtr<T>& operator=(MyAutoPtr<T>& rhs);

Why do you need that 'U' anyway, release should return the
pointer to be passed to reset, so T and U should be equal.


He needs it to support polymorphism. When D is derived from B,
MyAutoPtr<B> should be constructible and assignable from
MyAutoPtr<D>.

But the OP could define copy-constructor and assignment
operator from T separately. For the copy-constructor, I recall
that this is needed. I am not sure if it is needed for the
assignment operator.


If I understand the context correctly, it is. A template
operator= will never stop the compiler from generating its
default copy operator=.

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