Re: [eigen] Alignment of a derived class

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 18.07.2012 23:29, Gael Guennebaud wrote:
> On Wed, Jul 18, 2012 at 4:18 AM, Martin Sälzle <martin.saelzle@xxxxxxxx> wrote:
> > struct Base
> > {
> >    Eigen::Vector4f vec4f_base;
> >    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
> > };
> >
> > struct Derived1 : public Base
> > {
> >    Eigen::Vector4f vec4f_derived_1;
> >    EIGEN_MAKE_ALIGNED_OPERATOR_NEW
> > };
> >  [...]
> > The final question is what would happen for Derived1 if Base does note have EIGEN_MAKE_ALIGNED_OPERATOR_NEW?
>
> On a 64bits system nothing special. On a 32bits system with SSE
> enabled, an abort or segfault if you create a Derived1 on the heap
> using "new Derived1".

Actually, if Derived1 still has an EIGEN_MAKE_ALIGNED_OPERATOR_NEW, it 
should be ok to use `new Derived1`, shouldn't it?

Of course it is better to just add EIGEN_MAKE_ALIGNED_OPERATOR_NEW to 
the base class -- and it won't harm if you add it to the derived classes 
as well.

Christoph





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Dipl.-Inf. Christoph Hertzberg
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Universität Bremen
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