NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c++-part2/16287

Internet Message Format | 1996-08-05 | 1.6 KB

Path: keats.ugrad.cs.ubc.ca!not-for-mail
From: [e-mail] (Kazimir Kylheku)
Newsgroups: comp.lang.ada,comp.lang.c,comp.lang.c++,comp.edu
Subject: Re: ANSI C and POSIX (was Re: C/C++ knocks the crap out of Ada)
Date: 9 Apr 1996 20:06:41 -0700
Organization: Computer Science, University of B.C., Vancouver, B.C., Canada
Message-ID: <[e-mail]>
References: <[e-mail]> <dewar.829051685@schonberg> <[e-mail]> <dewar.829096975@schonberg>
NNTP-Posting-Host: keats.ugrad.cs.ubc.ca

In article <dewar.829096975@schonberg>, Robert Dewar <[e-mail]> wrote:
 >Linux simply checks that the end of the buffer is in the memory area,
 >which is not the check you would like to see. That's what I was talking
 >about when I noted that this kind of uncertainty would not occur in
 >a language with a reasonably complete type model.

Precisely. The kernel defends itself against making a faulty dereference that
would trigger an exception, but will happily corrupt your valid data, unless
stated buffer range sticks over into an unmapped page.

 >What exactly *is* the wording of the POSIX standard here (Lawrence, you
 >must have it at hand, please quote it exactly). The interesting thing
 >is to determine whether this definition says enough to make *any* use
 >of read defined without appealing to "unwritten rules". I would guess
 >not!

Unwritten rules, or paranoia. Take your pick! (Door #2 for me, please)

The standard is basically very good at telling you what the functions do.

BTW, I checked the Ada POSIX standard too, but that reads like a VCR manual
from 1984.  ;)  heh
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