------- Comment #13 from tjgolubi at netins dot net 2010-03-01 23:23 -------
Subject: Re: std::unique_ptr::reset() does not conform to N3035.
I think you are correct now. Thank you for the explanation.
terry
----- Original Message -----
From: "redi at gcc dot gnu dot org" <gcc-bugzi...@gcc.gnu.org>
To: <tjgol...@netins.net>
Sent: Monday, March 01, 2010 4:38 PM
Subject: [Bug libstdc++/43183] std::unique_ptr::reset() does not conform to
N3035.
>
>
> ------- Comment #12 from redi at gcc dot gnu dot org 2010-03-01
> 22:38 -------
> Bear in mind that a custom deleter with custom pointer type might have
> very
> different semantics for comparing pointer values and for invoking the
> deleter.
> Consider a custom D::pointer which keeps a generation count, which is not
> used
> when comparing for equality:
>
> template<class T>
> struct MyDeleter {
> struct pointer {
> int generation;
> T* ptr;
> pointer() : generation(), ptr() { }
> bool operator==(pointer rhs)
> { return ptr == rhs.ptr; }
> };
> void operator()(pointer p) const
> {
> do_something(ptr.generation);
> delete p.ptr;
> }
> void do_something(int gen);
> };
>
> Your suggested implementation would not update the value, because the
> equality
> test is true, but that would be wrong i.e. you would have failed to reset
> the
> unique_ptr as requested by the user.
>
>
> --
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43183
>
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--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43183
