Re: [boost] [integer] Create (u)int_natural_t

From: Martin Bonner (martin.bonner_at_[hidden])
Date: 2005-09-29 05:25:43

----Original Message----
From: Simon Buchan [mailto:simon_at_[hidden]]
Sent: 29 September 2005 10:21
To: boost_at_[hidden]
Subject: Re: [boost] [integer] Create (u)int_natural_t

> Daryle Walker wrote:
>> The "int" type was supposed to match the processor's natural built-in
>> integer processor.  That was easy to maintain in the 16- and 32-bit
>> eras, but got screwed up when we started 64-bit computing.  The C
>> and C++ communities decided to expand its integer types by keeping
>> the current types at their 32-bit-era sizes and extended the type
>> system with a "long long" instead of moving "int" and "long" up and
>> adding a "short short".  Now we don't have a convenient way to name
>> the best integer type in a portable fashion.  I suggest we add a
>> "int_natural_t" typedef to <boost/cstdint.hpp> to name the best
>> integer type (and a corresponding "uint_natural_t").  We would have
>> to research what that type is for each compiler and/or platform
>> combination and use #conditionals. 

I don't think it's worth it.  The performance difference between a 16-bit
integer and 32-bit integer on a PDP-11 was pretty significant.  Is there any
noticable difference between a 32-bit and 64-bit integer on any of the
64-bit processors?

> Isn't int the 'natural' integer type, by definition?
Depends what you mean by "natural", but for a normal English meaning,
probably not.

> I never understood why long didn't become the 64-bit type. It seems
> pointless to have int and long the same size on 32-bit.  

Oh god no!  The thread that would not die!  This has been argued to death on
comp.std.c.  

The reason long didn't become the 64-bit type is that most commercial C
compiler vendors wanted to continue to support code their customers had
written that assumed long was exactly four eight-bit bytes.  

You can argue as long as you like that the problem is in that code (and I
would agree with you).  It won't change the fact that telling your customers
they are wrong is not usually the route to commercial success.

> Who still writes 16-bit code on desktop, anyway? :D
Nobody ... but who still writes for the desktop?  Think about the number of
car radios (as just one example) compared to the number of PCs.
-- 
Martin Bonner
Martin.Bonner_at_[hidden]
Pi Technology, Milton Hall, Ely Road, Milton, Cambridge, CB4 6WZ,
ENGLAND Tel: [phone]