Path: utzoo!attcan!utgpu!watmath!watdragon!lion!thfisher
From: thfisher@lion.waterloo.edu (Terry Fisher)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Lattice 5.04 problem with free()
Message-ID: <17724@watdragon.waterloo.edu>
Date: 1 Nov 89 15:27:50 GMT
References: <36769@srcsip.UUCP> <37167@lll-winken.LLNL.GOV> <36899@srcsip.UUCP> <GILHAM.89Oct31100813@cassius.csl.sri.com>
Sender: daemon@watdragon.waterloo.edu
Reply-To: thfisher@lion.waterloo.edu (Terry Fisher)
Organization: U. of Waterloo, Ontario
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In article <GILHAM.89Oct31100813@cassius.csl.sri.com> gilham@csl.sri.com (Fred Gilham) writes:
>
>| As long as we are on the subject of Lattice, why doesn't this macro seem to
>| work?  (I'm rather new to macrodom, so this is probably a silly one) I
>| have some terribly long nasty expressions that need to be squared, and
>| SQR(moocow) never returns what I expect:
>|
>| #define SQR(x) (x*x)
>|
>
>probably because moocow gets evaluated twice, which I bet is not what
>you want!

The fact that the expression gets evaluated twice is only an optimization
problem.  The macro should be changed to 
	#define SQR( x ) ((x) * (x) )

Consider the line SQR( 2+3 ).
#define SQR( x ) (x * x ) causes the above to be substitued with
	2+3*2+3 = 11
#define SQR( x ) ((x) * (x)) yields the expression
	(2+3)*(2+3) = 25 as desired.

>-Fred Gilham     gilham@csl.sri.com

Terry Fisher		thfisher@lion.uwaterloo.ca
			thfisher@lion.waterloo.edu
			{...}!watmath!lion!thfisher