Re: [boost] is_polymorphic and unions

From: Nicodemus (nicodemus_at_[hidden])
Date: 2003-03-18 23:59:51

David Abrahams wrote:

>Nicodemus <nicodemus_at_[hidden]> writes:
>
>  
>
>>I did it, but it didn't work. is_class<some_union>::value evaluates to
>>true. 8/
>>
>>I believe that is_polymorphic<some_union>::value should evaluate to
>>false, since unions can't be polymorphic.
>>    
>>
>
>Sure, but if we don't have a way to reliably distinguish unions from
>classes, we're out of luck because there's no way to make
>is_polymorphic do something special for unions.
>
>We could put in the test for is_union and then ask users to
>specialize is_union<U> for their unions U until they get compiler
>support for that type trait.
>
>best-i-can-do-ly y'rs,
>Dave
>

I thought that would be the case, ie, no way to distinguish betwen a 
union and a class... but it seems good enough, considering that unions 
are rarely used anyway.