[ub] Justification for < not being a total order on pointers?

Nevin Liber nevin at eviloverlord.com
Mon Aug 26 18:12:15 CEST 2013


On 26 August 2013 11:00, Jeffrey Yasskin <jyasskin at google.com> wrote:

>
> Could someone explain why we need to allow operator<(T*) to be a non-order?
>

It comes from C.  I believe it comes from the days of segmented
architectures.

I do not know of any modern machines that have such architectures and have
C++11 compilers for them.  Whenever it comes up for discussion on various
reflectors, no one has mentioned one either.  I for one would like to see
this restriction go away.

Armchair thought:  maybe we should propose a total ordering for pointers
(for C++17 at this point) and see if anyone objects?


All that being said, I believe Library is inconsistent in its use of
operator< vs. std::less<T>, and that needs to be addressed separately.
Pointers are the current poster child for the issue but user code might be
specializing std::less as well.
-- 
 Nevin ":-)" Liber  <mailto:nevin at eviloverlord.com>  (847) 691-1404
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.open-std.org/pipermail/ub/attachments/20130826/c835c4e0/attachment.html 


More information about the ub mailing list