Re: How to elegantly get the enum code from its string type

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 14 Apr 2010 16:35:22 -0700 (PDT)
Message-ID:
<dc045546-be94-4e78-952e-9e262407a55f@11g2000yqr.googlegroups.com>
On Apr 15, 12:15 am, "Leigh Johnston" <le...@i42.co.uk> wrote:

"James Kanze" <james.ka...@gmail.com> wrote in message

news:b957812e-e4e3-47be-a591-156e6224e99a@g30g2000yqc.googlegroups.com...

More generally, unsigned types, in C++, are not cardinal
numbers, but have very special (and somewhat curious)
semantics. You use them in two cases: when you're doing bit
manipulations, and unsigned char for raw memory. (Plus the
very rare case where you actually want the special
semantics---calculating hash codes is the only case which
comes to mind.)


Sorry James but you are spouting garbage again. One word: size_t.


So who uses size_t on a modern machine?

Back when C was being standardize, 16 bit machines were still
legion, and the extra bit was necessary. Today, realistically,
size_t is an anachronism, and not really necessary. (It's worth
noting that the STL was originally developed using Borland C++,
on a 16 bit machine. Which possibly accounts for it's use of
unsigned size_type as well.)

Even today, size_t is designed to support the very lowest level
of programming, and there are contexts (e.g. writing a garbage
collector) where you really do need that extra bit. (A garbage
collector on a 32 bit machine has to handle memory blocks which
are larger than 2GB.) But you don't normally use it in
application level code, except to avoid signed/unsigned
comparison warnings when using the STL.

--
James Kanze

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