[phobos] Fwd: Re: Ruling out arbitrary cost copy construction?

[SHOO]

As for this matter, the direct relations seem to be surely thin in 
SealedRange as you say. However, I think that there is relation for the 
situation that SealedRange is needed and the lifetime of data closely.
It reduces a use opportunity of SealedRange to make the situation that 
cannot access dead data.
I think that copy constructor and move are not regarded as important in 
the situation that can expose reference data without worry of to access 
the dead data.

--
SHOO


(2010/11/03 3:08), Steve Schveighoffer wrote:
> All of these have nothing to do with sealed ranges.  They have to do with data
> lifetime.  If you destroy data and then try to access it, you will have problems
> with or without sealed ranges.  In addition, only one instance you show has a
> sealed range in it.  The rest either don't have ranges or are not sealed.
>
> Having a sealed range does not necessarily mean that the user cannot shoot
> themselves in the foot and delete the data while still maintaining references to
> it.  This problem is mostly solved by having the data or at least the pointer to
> the data on the heap, destroyed by the GC when no longer needed.
>
> Even then, this does not rule out the user calling clear on the pointer.
>
> SealedRange is not a magic bullet for memory issues, and all these issues exist
> with or without sealed ranges or expensive copy construction.
>
> What SealedRange *does* do is allow the container to have complete control over
> the storage for the data.  This means it can:
>
> a) intercept all accesses to the memory, including writes and reads.
> b) use abstracted allocation schemes.
>
> -Steve
>
>
>
> ----- Original Message ----
>> From: SHOO<zan77137 at nifty.com>
>> Another viewpoint.
>>
>> Is  SealedRange really appropriate?
>>
>> All these are caused by the same  problem:
>> - http://ideone.com/x1Zus
>> - http://ideone.com/iM18Q
>> -  http://ideone.com/TTin3
>> - http://ideone.com/x4b0o
>>
>> We should consider  that we grope the common solution for these problems.
>> It is the method that  block the access to reference data of which
>> instance was  deleted.
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