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From: franka@mmintl.UUCP (Frank Adams)
Newsgroups: comp.lang.c
Subject: Re: swaps with arrays
Message-ID: <2366@mmintl.UUCP>
Date: Fri, 11-Sep-87 15:23:40 EDT
Article-I.D.: mmintl.2366
Posted: Fri Sep 11 15:23:40 1987
Date-Received: Tue, 15-Sep-87 04:01:39 EDT
References: <2376@zeus.TEK.COM> <110@umigw.MIAMI.EDU> <1955@sol.ARPA> <111@umigw.MIAMI.EDU>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Multimate International, E. Hartford, CT.
Lines: 20

In article <111@umigw.MIAMI.EDU> steve@umigw.UUCP (steve emmerson) writes:
>Although I can see the validity of this argument (and I hope I've
>restated it correctly) I would argue that the swapping of arrays does
>have valid meaning -- namely an element-by-element exchange of values.
>This causes each array to become the other and, to me at least, is a
>straightforward consequence of swap semantics.  As such, this
>functionality should be included in any generic swap routine.

The point is that a generic facility should work for all objects in some
category.  The appropriate category for a swap macro is that of *assignable*
objects in the language.  And in C, as the result of a series of decisions
which seemed like good ideas at the time, arrays are not assignable.

It is true that the semantics of the assignment of arrays is obvious and
straightforward (I think -- there may be some traps hiding there somewhere).
This is beside the point.  The point is that C doesn't support it.
-- 

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108