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From: davidsen@steinmetz.UUCP (Davidsen)
Newsgroups: net.lang.c
Subject: Re: Address of array
Message-ID: <685@steinmetz.UUCP>
Date: Fri, 14-Mar-86 10:05:04 EST
Article-I.D.: steinmet.685
Posted: Fri Mar 14 10:05:04 1986
Date-Received: Sun, 16-Mar-86 00:47:15 EST
References: <750@abic.UUCP> <211@dg_rtp.UUCP>
Reply-To: davidsen@kbsvax.UUCP (Davidsen)
Organization: GE CRD, Schenectady, NY
Lines: 49
Summary: 

In article <211@dg_rtp.UUCP> throopw@dg_rtp.UUCP (Wayne Throop) writes:
>> I have noticed that different compilers treat the & operator differently
>> when it is applied to arrays.  In particular, the UNIX compiler I have
>> been using warns against it.  K&R explicitly deny its legality.
>> However, the operation seems to me to be perfectly
>> reasonable when the desired result is a pointer to the array rather
>> than a pointer to the first element of the array.
>
>I agree that C's treatment of array/function/struct addresses is
>inconsistant, confusing, and limiting.  In essence a small notational
>convenience was traded for a large consistancy headache.  I think the
>tradeoff was wrong, but I'm not sure that your proposal would clarify
>things.

I believe that to support reasonable portable code C *must* allow the address
operator on an array, even if it is not required. Consider:

prog.c:
	#include "globals.h"  /* project global symbols and types */

	foo() {
	  LOCAL m,n;

	  process(&m);
	}

globals.h:
	typedef long LOCAL[10];

================
Since LOCAL is a typedef which is an array, the programmer would not be
able to write code which would work with a legal typedef for LOCAL
unless the & operator was allowed for an array. To require special code
to handle arrays and scalars defeats the intent of information hiding,
and requires global changes to the source is a typedef is changes, for
instance, from an array to a structure.

This was pointed out to me by someone on X3J11, but I can't remember
who in order to give credit for this example.
-- 
	-bill davidsen

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