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

Subject: Re: [boost] [optional] memory use for optional refs and ptrs
From: Sebastian Redl (sebastian.redl_at_[hidden])
Date: 2010-10-06 08:25:14

On 06.10.2010 14:09, Rutger ter Borg wrote:
>
> On 2010-10-06 13:11, Stewart, Robert wrote:
>
>> (I haven't looked, but I do hope that the bool follows the optional 
>> value to reduce padding overhead.)
>
> It doesn't, the boolean is followed by the optional value (see 
> boost/optional/optional.hpp lines 447-448).
I really don't think it makes a difference. Unless you're using 
compiler-specific packing instructions, the size of a struct will always 
be a multiple of the largest alignment of any of its subobjects. In 
other words, no matter where you place the bool, it will take as much 
space as the alignment of the value.

Sebastian