Path: utzoo!utgpu!cunews!micor!latour!revcan!darren
From: darren@revcan.UUCP (Darren Morbey)
Newsgroups: comp.lang.c
Subject: The nonexistent ^^ operator
Keywords: xor
Message-ID: <161@revcan.UUCP>
Date: 24 Apr 91 17:01:26 GMT
Organization: Revenue Canada, Taxation; Office Communications Division
Lines: 24

I left as an exercise on making
#define XOR(A,B) ( (!(A)&&(B)) || ((A)&&!(B)) )
execute A twice and B no times (and B twice.)
The only respondent correctly identified this as operands with
side effects.  In this case, XOR(++x,b) executes B:
  no times  if x is initially -2.
  twice     if x is initially -1.
The prize goes to Ian Collier (Ian.Collier@prg.ox.ac.uk) for submitting
something like this (and being the only one to do so.)

As I was reviewing some of the responses and followup articles
to the logical XOR question, I came across a pretty good argument for
not having ^^.  This article comes from a "Dan," who says "since you
"can always implement a non-short-circuit logical operator, there's no
"reason for the language to provide any logical operators other than
"the short-circuit ones."

Due to the end of my co-operative work term on Friday, I'm unable
to accept any responses anymore. :-(  I may be able to get back on
in university ( I don't know though ).  I would like to thank all
of you for listening and responding to my question.

[ Darren Morby     +1 613 957 9281     {uunet|lsuc|fts1}!revcan!darren ]
[ Revenue Canada Taxation, 3052-400 Cumberland St, Ottawa,ONT  K1A 0L8 ]