Question about explicit template instantiation

[Edward Diener]

Janice Caron wrote:
> On 10/02/2008, Edward Diener <eddielee_no_spam_here at tropicsoft.com> wrote:
>> I still do not understand what the object used for the instantiation is.
>> In your example above what is:
>>
>> A!(int)
>>
>> ? Is it some kind of namespace ?
> 
> Yes. It is exactly a namespace.
> 
> 
> 
>> Can I say:
>>
>> A!(int) x;
>>
>> ?
> 
> Sometimes, but only in special case. If you don't specify a member of
> the namespace, then the compiler will /assume/ a member whose name is
> the same as that of the template. So, if we have:
> 
>     template A(T)
>     {
>         int A;
>     }
> 
> then
> 
>     A!(int) x;
> 
> would be shorthand for
> 
>     A!(int).A x;
> 
> But if there wasn't an A in the namespace, then it wouldn't compile.
> That little "trick" is really, really useful, because it can make for
> a lot less typing. So - in general - A!(T) with no member, is the same
> thing as A!(T).A, if A!(T).A exists.
> 
> /What/ is it, depends. It's whatever A!(T).A is.

Thanks for the explanation !