[boost] Re: Re: Re: [ANN] State of Boost.Variant

From: Bohdan (gejrlaug_at_[hidden])
Date: 2003-09-25 18:53:25

"Rozental, Gennadiy" <gennadiy.rozental_at_[hidden]> wrote in message
news:1373D6342FA1D4119A5100E029437F6405E1FA72_at_clifford.devo.ilx.com...
> > "Rozental, Gennadiy" <gennadiy.rozental_at_[hidden]> wrote in
> > message
> > news:1373D6342FA1D4119A5100E029437F6405E1FA69_at_clifford.devo.ilx.com...
> > > Probably not. Because of the alignment.
> > >
> > > struct A {
> > > int a;
> > > char b;
> > > };
> > >
> > > sizeof(A) = 8
> > >
> > > Gennadiy
> > >
> >
> > I'm using bcc32 option -a1 -Vx -Ve which means that
> >     1. -a1 : aligment is 1
>
> This basically says - disregard alignment
>
> >     2. -Vx : Zero-length class data member
> >     3. -Ve : Zero-length empty base classes
> >
> > And with this option set your example gives size 5,
> > and sizeof(variant<int>) is still is 8.
>
> This is probably because Eric is using int as a type for selector member. I
> mentioned it to him during review that it should be char. On the other hand
> I found that In majority of the cases (when you are not or could not ignore
> alignment) size will be the same.
>
> > regards,
> > bohdan
>
> Gennadiy.
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