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From: karl@haddock.ISC.COM (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: typeof isn't enough to define swap correctly
Message-ID: <1088@haddock.ISC.COM>
Date: Wed, 9-Sep-87 19:13:18 EDT
Article-I.D.: haddock.1088
Posted: Wed Sep  9 19:13:18 1987
Date-Received: Fri, 11-Sep-87 07:13:18 EDT
References: <557@rocky.STANFORD.EDU> <343@wrs.UUCP>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Boston
Lines: 9
Summary: "lvalueness" and "&-ability" are not equivalent

In article <343@wrs.UUCP> dg@wrs.UUCP (David Goodenough) writes:
>both args should be lvalues and hence &-able

Registers and bitfields are modifiable lvalues, but not &-able.
Arrays and consts (in ANSI C) are &-able lvalues, but not modifiable.

The swap macro you gave requires &-able, modifiable lvalues as args.

Karl W. Z. Heuer (ima!haddock!karl or karl@haddock.isc.com), The Walking Lint