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Date: Sat, 22 Feb 1997 22:45:03 +0100
To: Alex Belits <abelits@phobos.illtel.denver.co.us>
From: Eivind Eklund <eivind@dimaga.com>
Subject: Re: hmm
Cc: audit-bin@FreeBSD.ORG, FreeBSD-hackers@FreeBSD.ORG
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[Alex Belits]
>>> with p=""  
>>> *p != '\0' && p[strlen(p) - 1] == '[' _still_ will read a byte p[-1].

[Terry Lambert]
>> What?
>> 
>> 	IF p = ""
>> 	THEN *p = '\0'
>> 
>> by definition of ""...

[Alex Belits]
>but p[strlen(p) - 1] will be p[-1]
>Optimization done by compiler may skip it, but depending on that will be
>rather dangerous.

&& is defined as short-circuiting.  If *p == '\0' the evaluation of
p[strlen(p) - 1] == '[' is guaranteed to be skipped.  Re-read your book on
C :)


Eivind Eklund perhaps@yes.no http://maybe.yes.no/perhaps/ eivind@freebsd.org