Re: [boost] [optional] memory use for optional refs and ptrs

Subject: Re: [boost] [optional] memory use for optional refs and ptrs
From: John Reid (j.reid_at_[hidden])
Date: 2010-10-05 09:42:58

Rutger ter Borg wrote:
> 
> Hello,
> 
> I'm looking into boost::optional<> as a replacement for some of my code 
> which has to deal with  optional values. However, it seems that cases 
> which are usually space-efficient optionals (e.g., ptrs in the form of a 
> null-ptr) do not have template specializations. In other words, boost 
> optional templates store a bool and the memory footprint of its template 
> parameter, regardless of type. I.e., optional references and pointers 
> take their space plus the space of an extra bool.
> 
> Is there a reason for this?
> 
Might someone want to store a null pointer in the optional? I'm not sure 
about the references though.

John.