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From: allan@cs.strath.ac.uk (Allan Black)
Newsgroups: net.lang.c
Subject: Re: swap() macro
Message-ID: <193@stracs.cs.strath.ac.uk>
Date: Fri, 20-Jun-86 13:20:22 EDT
Article-I.D.: stracs.193
Posted: Fri Jun 20 13:20:22 1986
Date-Received: Mon, 23-Jun-86 03:32:29 EDT
References: <1201@brl-smoke.ARPA>
Reply-To: allan@cs.strath.ac.uk (Allan Black)
Organization: Department of Computer Science at Strathclyde University, UK.
Lines: 21

In article <1201@brl-smoke.ARPA> Schauble@MIT-MULTICS.ARPA writes:
>Can someone construct a version that makes
>    int *a, *b;
>    swap (*a++,*b++);
>work right?

#define swap(p,q) {int *x = &(p), *y = &(q); int z = *x; *x = *y; *y = z;}

This will only work for type 'int'; if you want to make it more general, try
something like:
{long *x = (long)(&(p)) etc.
But be careful with something like that - there's no typechecking, so you
can easily mix pointers up, with disastrous results!

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