Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!ihuxv!rck
From: rck@ihuxv.ATT.COM (R. C. Kukuk)
Newsgroups: comp.lang.c
Subject: Re: comma operator
Summary: comma operator and the (in)famous swap
Message-ID: <2382@ihuxv.ATT.COM>
Date: 20 Jan 88 17:38:59 GMT
References: <3819@sigi.Colorado.EDU> <5080013@hpfcdc.HP.COM> <7120@brl-smoke.ARPA> <7137@brl-smoke.ARPA>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 14

In article <7137@brl-smoke.ARPA>, gwyn@brl-smoke.ARPA (Doug Gwyn ) writes:
> In article <3887@sigi.Colorado.EDU> swarbric@tramp.Colorado.EDU (SWARBRICK FRANCIS JOHN) writes:
> >#define swap(a,b) ((a) = ((b) = ((a) = (a) ^ (b)) ^ (b)) ^ (a))
> >He says it will work for anything (int, char *, etc.).
> 
This oldie fails when a == b.  Why?  Think about it.


Re: Another discussion in this news group --

Note that I said "a == b"; not "a = b". :-)

Ron Kukuk
AT&T Bell Labs