From: Sean Middleditch <elanthis@...>
Date: 2002-04-12T03:36:38+09:00
Subject: Re: Is eval a code/design smell?

On Thu, 2002-04-11 at 14:19, Paul Brannan wrote:
> On Fri, Apr 12, 2002 at 02:56:46AM +0900, Sean Middleditch wrote:
> > Of course, with C++, you do directly access any byte in memory owned by
> > the program you want, so things like public/private/friend are simply
> > there as "safety" checks - not any kind of true protection or security
> > mechanism.
> 
> It's more than that.  In C++, bypassing the access control is undefined.
> 
> You must first find out the memory location where the data you want is.
> There is no portable way to do this.  It's perfectly legal for a
> compiler to only allow this kind of access on Tuesdays between 6:30 and
> 10:00pm.
> 
> GOTW has an interesting (and somewhat humorous) article on the subject:
> 
> http://www.gotw.ca/gotw/076.htm

Ya, well, still - the point is, it's possible, whereas in Ruby (assuming
no C extensions, which is similar to assuming a C program doesn't
include kernel extensions) you are forced to play by the rules Ruby lays
down.  You can't, or shouldn't be able to, play dirty tricks on the
interpreter.

With C/C++, assuming I know what compiler/OS the code will be compiled
on, I can very easily figure out what the byte locations will be, and
access those; even using some funky type-casting if I have to (depending
on compiler).

> 
> Paul
>