Re: [boost] [pool] future directions

From: Andrey Semashev (andysem_at_[hidden])
Date: 2007-05-09 16:26:32

Hello Michael,

Thursday, May 10, 2007, 12:13:18 AM, you wrote:

> "David Abrahams" <dave_at_[hidden]> wrote in message 
> news:87lkfyklpu.fsf_at_grogan.peloton...
>>
>> on Tue May 08 2007, "Michael Gopshtein" <mgopshtein-AT-gmail.com> wrote:
>>
>>> "Atry" <pop.atry_at_[hidden]> wrote in message
>>> news:fd8b80680705080147t5c561dd8l9fc0ee8ede2120c7_at_mail.gmail.com...
>>>> Yes, "defragment" or other automation memory management is useful, but 
>>>> the
>>>> existing code depends on native pointer would be very hard to work
>>>> together,
>>>> almost all C++ code need to recode if they want to use these futures.
>>>>
>>>
>>> I do "feel" that just moving object's memory is not safe, but can't find
>>> explanation why it will cause problems. Can you give an example of a 
>>> class
>>> for which this will not work?
>>
>>  struct B;
>>
>>  struct A {
>>    A(B*p) : p(p) {}
>>    B* p;
>>  };
>>
>>  struct B : noncopyable {
>>    B() : px(new A(this)) {}
>>    auto_ptr<A> px; // invariant: px->p == this
>>  };

> So, basically, it's any case where the object has pointers to it's internal
> members, right?

> Are there other cases that the object can't be "moved" (it's more of a
> theoretical interest)?

In general, if there is anywhere in the Universe a pointer or
reference to the object or its part, the object cannot be moved.

-- 
Best regards,
 Andrey                            mailto:andysem_at_[hidden]