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From: archiel@hercules.UUCP (Archie Lachner)
Newsgroups: net.lang.c
Subject: Re: pointer question
Message-ID: <155@hercules.UUCP>
Date: Fri, 6-Apr-84 17:00:49 EST
Article-I.D.: hercules.155
Posted: Fri Apr  6 17:00:49 1984
Date-Received: Sun, 8-Apr-84 07:05:43 EST
References: <7624@mgweed.UUCP> <937@inuxc.UUCP>
Organization: Tektronix, Beaverton OR
Lines: 28

As I read Kernighan and Ritchie (K & R), the assertion that the statement

	p = p + 4;

where p is a pointer, is dangerous and non-portable is completely wrong.
In section 5.4, p. 98, it is stated that when an int or constant is
added to a pointer, it is first scaled by the size of the object the pointer
points to.  For example, and I am quoting directly now,

	"The construction

		p + n

	means the n-th object beyond the one p currently points to."

As far as I am concerned, K & R contains the definition of the C language.
Expressions such as "p + 4" above are not dangerous and completely portable,
at least to machines and systems where the C compiler implements the language
correctly.
-- 

				Archie Lachner
				Logic Design Systems Division
				Tektronix, Inc.

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