Re: [boost] [type_traits] VC9/TR1 failures vs Boost

From: Richard Webb (richard.webb_at_[hidden])
Date: 2008-01-20 13:06:58

Beman Dawes <bdawes <at> acm.org> writes:

> 
> > Sigh... it depends, as far as TR1 is concerned this started out false, and 
> > then changed to true (in the final TR1 draft N1836 anyway).  However, the 
> > std whitepaper has for the moment anyway changed it back again... well sort 
> > of anyway.
> 
> John,
> 
> Do you have any idea if the change back in the current WP was deliberate 
> or an editing glitch? Also, does your "well sort of anyway" comment mean 
> you think the current WP is unclear?
> 

TR1 says that 'is_base_of<T, U> is true if T and U are the same type'.
The WP removes the 'is the same type' bit, but adds an 'a class is considered
it's own base'.
I read this as:
TR1: is_base_of<T, T> is true
WP: is_base_of<T, T> is true if T is a class and false otherwise (for int in
this example).

Is this what you mean? (i don't know what the pre-n1836 spec said, so i'm just
guessing here).