RCArray is unsafe

Walter Bright via Digitalmars-d digitalmars-d at puremagic.com
Mon Mar 2 14:57:27 PST 2015

On 3/2/2015 1:09 PM, "Marc =?UTF-8?B?U2Now7x0eiI=?= <schuetzm at gmx.net>" wrote:
> "I have discovered a marvellous solution, but this post is too short to describe
> it."

Fortunately, Fermat (er, Andrei) was able to pass along his dazz idea to me this 
afternoon, before he expired to something he had to attend to. We were both in 
the dumps about this problem last night, but I think he solved it.

His insight was that the deletion of the payload occurred before the end of the 
lifetime of the RC object, and that this was the source of the problem. If the 
deletion of the payload occurs during the destructor call, rather than the 
postblit, then although the ref count of the payload goes to zero, it doesn't 
actually get deleted.

I.e. the postblit manipulates the ref count, but does NOT do payload deletions. 
The destructor checks the ref count, if it is zero, THEN it does the payload 

Pretty dazz idea, dontcha think? And DIP25 still stands unscathed :-)

Unless, of course, we missed something obvious.

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