kicad-developers team mailing list archive

[Wayne Stambaugh <stambaughw@xxxxxxxxxxx>]

On 9/28/2010 12:43 PM, Dick Hollenbeck wrote:
> 
>> I probably would never personally use shared_ptr because in my mind it
>> is slightly beyond what an average C++ programmer uses on a day to day
>> basis, and it obscures the clear notion of "object ownership".
>>
>> I have never (I am old, this is a long long time, and countless lines of
>> code) been in a position where I could not assign object ownership
>> clearly to one container over another.  If ever this became obscure, I
>> would probably backup and take another look.
>>
>> Object ownership is something to keep one's eye on.
>>
>>
>> Dick
>>   
> 
> 
> This was an opinion I expressed about shared_ptr, which hopes to relieve
> me of having to think clearly about object ownership.  I have no problem
> thinking about object ownership, so I have this opinion about
> shared_ptr.  IMO, shared_ptr is a solution without a sufficiently large
> problem.  Managing object ownership is not a significantly difficult
> design responsibility, and has always been part of C/C++ programming.
> 
> 
> I don't feel the same way about auto_ptr, which is *one* reasonable way
> to deal with heap allocated objects in the face of exceptions.  If no
> exceptions can occur, auto_ptr is not useful.  If exceptions, then this
> is a sufficiently large problem to justify auto_ptr, but it is not the
> only solution.  auto_ptr is one reasonable and simple solution.  Another
> one that can also work is to simply stash the pointer soon after heap
> instantiation into the object's eventual owner, and then the problem
> gets moved to the owner.  When the owner's destructor gets called, it
> deletes the newly instantiated owned object.  Either solution is better
> than simply leaving the pointer on the heap and not copying it to the
> owner and not using auto_ptr, and then experiencing a thrown exception
> in that function that leaves the object exposed to a memory leak.
> 
> 
> Just wanted to clarify: 
> 
>   auto_ptr: good sometimes,
>      if you cannot copy pointer to the eventual owner soon enough,
> 
>   shared_ptr: not worth the cost.

Dick,

I have already changed my code to not use shared_ptr.  It isn't quite as clean,
but it is close.  I just have a bit more validation to do before I commit the
changes.  This also means that I will not be changing the included boost headers.

Wayne

> 
> 
> Probably few care about my opinion anyway.  There's never a shortage of
> opinions, in my opinion.
> 
> 
> Dick
> 
> 
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