Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!snorkelwacker.mit.edu!hsdndev!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.c
Subject: Re: The nonexistent operator (along = v. == lines)
Message-ID: <25483:Apr621:53:3191@kramden.acf.nyu.edu>
Date: 6 Apr 91 21:53:31 GMT
References: <156@revcan.UUCP> <157@revcan.UUCP> <372@smds.UUCP>
Organization: IR
Lines: 10

In article <372@smds.UUCP> rh@smds.UUCP (Richard Harter) writes:
> #define AND(a,b)  ( !(a) ? ((b) && 0) : !!(b)  )
> appears to do the trick, modulo typoes.  However it occurs to me that a
> "clever" optimizing compiler would recognize that ((b) && 0 ) is always
> false and bypass the evaluation of b.  Perhaps the language lawyers can
> tell us if the language specifications *require* that b be evaluated.

I'm not much of a language lawyer, but yes, b is evaluated once.

---Dan