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From: Russell Hind (rhind_at_[hidden])
Date: 2004-07-14 09:12:42

Caleb Epstein wrote:

> I've been perusing the source code of <boost/shared_ptr.hpp> and
> noticed that it uses the <boost/detail/shared_count.hpp> class to do
> reference counting and not <boost/detail/atomic_count.hpp> (unless
> defined).
> Can anyone comment on the reasoning behind using a lightweight
> mutex-protected counter instead of an atomic counter? I'd think that
> an atomic counter would be faster, but I suspect that there is a good
> reason for protecting the count with a mutex. This then begs the
> question of why use the atomic counter in the situations mentioned
> above?

If you look at shared_count, you'll see it has to keep track of 2
values, strong_count and weak_count, you can't do this with 'atomic
count' so therefore it uses lwm.



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