[boost] Re: Safe bool idiom

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2003-09-11 11:39:05

David Abrahams wrote:
> "Peter Dimov" <pdimov_at_[hidden]> writes:
> 
>>This improvement has been first suggested by Daveed Vandevoorde. 
> 
> Are you sure?  I didn't hear it from Daveed until after:
> 
>    http://lists.boost.org/MailArchives/boost/msg44446.php
> 
> which was mostly ignored so I figured nobody cared.

I would have cared, but in the context of bool_testable, other things 
have to be taken into account, like the freedom for the user to add an 
operator int(). If he does that, the conversion to bool would break if 
it isn't a real operator bool.

I think that both idioms have their place, and in the case of shared_ptr 
it seems that Peter's approach has some important aspects that my 
approach used in bool_testable can't provide. Anyway, it's good to 
discuss it and I think we are on a good way fixing the overhead for 
shared_ptr et al with the member variable pointer instead of the member 
function pointer. I'd vote for changing it, even if the performance 
overhead seems small. Smart pointers are just too important to leave out 
an optimization...

Regards, Daniel

-- 
Daniel Frey
aixigo AG - financial training, research and technology
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eMail: daniel.frey_at_[hidden], web: http://www.aixigo.de