[boost] Re: shared_ptr reference count

From: Tom Widmer (tom_usenet_at_[hidden])
Date: 2004-03-08 05:19:36

On Fri, 5 Mar 2004 11:43:12 -0800, "John McGinty" <john_at_[hidden]>
wrote:

>Is there any reason why shared_ptr does not use atomic_count (using 
>InterlockedIncrement, InterlockedDecrement) for the reference count? 
>The lightweight mutex used to protect the count in the current 
>implementation is a spin lock that sleeps when contended. Using 
>atomic count would offer performance improvements in both the 
>uncontended and contended cases.

You can't atomically modify two variables at once without some kind of
mutex but there are two reference counts. I suspect that's the reason.

Tom
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