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From: utility@quiche.cs.mcgill.ca (Ronald BODKIN)
Newsgroups: comp.lang.c
Subject: macro inefficiency
Message-ID: <5062@quiche.cs.mcgill.ca>
Date: 27 Sep 90 16:18:09 GMT
References: <168@thor.UUCP>> <AavhqRS00VpH844aBW@andrew.cmu.edu> <2514@cirrusl.UUCP>
Organization: SOCS - Mcgill University, Montreal, Canada
Lines: 12

In article <2514@cirrusl.UUCP> dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi) writes:
[suggesting a swap macro with typeof:]
>I have seen a "typeof" keyword proposed that would fix this deficieny:
>
>#define swap(a,b)  do { typeof(a) tmp; tmp = a;  a = b; b = tmp; } until (0);
	This should just be defined as:
#define swap(a,b)  { typeof(a) tmp; tmp = a;  a = b; b = tmp; }

(check out your C grammar carefully and you will see that
{ declaration* statement* } is always a valid statement).

		Ron