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From: Scott Meyers <NeverRead@aristeia.com>
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Subject: Re: Why is std::array an aggregate?
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Faisal Vali wrote:
> On Dec 20, 10:00 pm, Scott Meyers <NeverR...@aristeia.com> wrote:
>> Johannes Schaub (litb) wrote:
>>
>>> I believe this can all be done using variadic templates:
>>> template<typename T, size_t S>
>>> struct array {
>>>   template<typename ...U>
>>>   constexpr array(U&&... u):elems{ u... } { }
>>>   T elems[S];
>>> };
>>> array<int, 3> a = { 1, 2 }; // works, is statically initialized
>> Alas, this won't work, because you can't deduce a template argument's
>> type from a brace initializer.  The standardizion people have decided
>> that such a type can be deduced in the context of auto, but not a
>> template.  I have no idea why.
> 
> 
> I thought we had established here
> http://groups.google.com/group/comp.std.c++/browse_frm/thread/b14c8fad6735a0d9?hl=en#
> that it would work.

Yes, my mistake, I forgot that a templated constructor taking multiple arguments
could be instantiated to match a brace initializer list as long as there is no
constructor taking a std::initializer_list parameter.  Thanks for reminding me
of this.

I thus agree that it appears that making std::array a non-aggregate does not
preclude static initialization.

Which brings me back to my question about whether std::array should be defined
to be one.

Scott

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