Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!rutgers!iuvax!bsu-cs!dhesi
From: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Newsgroups: comp.unix.wizards
Subject: Re: Referencing through a null pointer
Message-ID: <2730@bsu-cs.UUCP>
Date: 25 Apr 88 19:23:35 GMT
References: <4729@cup.portal.com> <1988Apr24.092740.8673@utzoo.uucp> <50676@sun.uucp>
Reply-To: dhesi@bsu-cs.UUCP (Rahul Dhesi)
Organization: CS Dept, Ball St U, Muncie, Indiana
Lines: 16

[0 stored at location 0, allowing access through null pointer]

A suggestion to system designers, to decrease the frustration of
customers who want to run software developed on systems that return 0
from a dereferenced null pointer.

So long as your memory management hardware is trapping references
through a null pointer and printing an error message, how about
allowing the user to set a switch that will cause such illegal trapped
references to be handled by an emulation routine that will cause a zero
to be returned and continue execution?

Conceptually this is not much different from emulation of illegal
(nonexistent) floating point instructions, or handling of page faults.
-- 
Rahul Dhesi         UUCP:  <backbones>!{iuvax,pur-ee,uunet}!bsu-cs!dhesi