Re: [boost] Ann: Floating Point Utilities Review starts today

From: John Maddock (john_at_[hidden])
Date: 2008-02-26 11:52:53

Martin Bonner wrote:
> I'm not sure I'm a pedantic language lawyer, but the standard says
> "In a union, at most one of the data members can be active at any
> time".  It is quite clear that experts in CLC++M regard John
> Maddock's version of setbits and getbits as undefined behaviour.  In
> general, I would regard using undefined behaviour as unacceptable for
> a boost library.  The floating point utilities are different, they
> pretty much /have/ to use undefined behaviour.  They also seem to be
> taking the correct approach of using #ifdef, and testing on as many
> platforms as possible (I haven't reviewed them yet).        
> 
> On the other hand, even if floating point utilities have to go
> through a minefield, there doesn't seem any point in wandering around
> more than necessary. Particularly if the tested compilers don't
> actually generate better code for the undefined behaviour version!   

Indeed, suggestion withdrawn! :-)

It all goes to show why I don't normally mess about at such a low level :-(

John.