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Re: structure members of packed structures
On Tue, 2003-07-15 at 09:51, Alexandre Oliva wrote:
> On Jul 15, 2003, Mark Mitchell <mark@codesourcery.com> wrote:
>
> >> Another question. What about
> >> struct __attribute__((packed)) Foo
> >> {
> >> T m;
> >> };
> >>
> >> here m happens to fall at an aligned address, and the size of Foo happens
> >> to be a multiple of that alignment. Should m be DECL_PACKED or not?
>
> > I say yes.
>
> Does this mean T needs packed ctors, dtor and member functions?
Yes.
> Are
> they implicitly generated from the non-packed ones, or must the user
> define them explicitly?
T should be declared packed itself. It does not make sense to have
sometimes-packed non-PODs. You would -- at the very least -- have to
make modifications to all the overloading rules.
All this is academic because we're not going to impelement it right now;
Nathan is going to do a minimal fix for a customer and move on. But we
were trying to figure out what the right answer *would* be so that we
can implement it "some day".
--
Mark Mitchell <mark@codesourcery.com>
CodeSourcery, LLC