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From: markb@sdcrdcf.UUCP (Mark Biggar)
Newsgroups: net.lang.c
Subject: Re: swap() macro
Message-ID: <2857@sdcrdcf.UUCP>
Date: Tue, 24-Jun-86 17:02:06 EDT
Article-I.D.: sdcrdcf.2857
Posted: Tue Jun 24 17:02:06 1986
Date-Received: Fri, 27-Jun-86 04:39:44 EDT
References: <1201@brl-smoke.ARPA> <3007@utcsri.UUCP>
Reply-To: markb@sdcrdcf.UUCP (Mark Biggar)
Organization: System Development Corporation R&D, Santa Monica
Lines: 24

In article <3007@utcsri.UUCP> greg@utcsri.UUCP (Gregory Smith) writes:
>In article <1201@brl-smoke.ARPA> Schauble@MIT-MULTICS.ARPA (Paul Schauble) writes:
>>Can someone construct a version that makes
>>
>>    int *a, *b;
>>    swap (*a++,*b++);
>>
>>work right?
>>
>#define swap( a,b ) { int *p1,*p2,t;\
>	p1= &(a); p2= &(b); t= *p1;*p1= *p2;*p2=t;}
>
>No, it isn't pretty.
>how about:
>
>#define swap(a,b) fswap(&(a),&(b))
>fswap(a,b) int *a,*b;
>{	etc.

BOTH of these die a horrible death if either argument is declared
"register".

Mark Biggar
{allegra,burdvax,cbosgd,hplabs,ihnp4,akgua,sdcsvax}!sdcrdcf!markb