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Path: utzoo!linus!decvax!harpo!eagle!mhuxl!houxm!ihnp4!mit-eddie!smh
From: smh@mit-eddie.UUCP
Newsgroups: net.lang.c
Subject: Re: & operator
Message-ID: <999@mit-eddie.UUCP>
Date: Sun, 4-Dec-83 11:47:56 EST
Article-I.D.: mit-eddi.999
Posted: Sun Dec  4 11:47:56 1983
Date-Received: Mon, 5-Dec-83 04:50:54 EST
References: <162@iwu1a.UUCP>
Organization: MIT, Cambridge, MA
Lines: 27


		char *in;
		char *out;
		out = &(*in++);
	Should "out" be set to "in" or "in + 1?"

Upon consideration of the types during the evaluation of the
right-hand-side, it seems clear that:
	- the & operator is applied to the value of the expression
	  inside the parentheses;
	- that value is type char, and that char is the one pointed
	  to by the original value of in;
	- the address of that character has type (char *) and indeed
	  is the original value of in.
Therefore, the code example ought to be equivalent to:
	out = in;
	*in++;
The dereferencing of pointer (the '*') seems nugatory, but may have
side effects such as causing a segmentation violation or accessing
a device register.

	Different compilers seem to have different opinions.  I believe
	it should be set to "in."

If this analysis is correct, which are the compilers with a different
opinion?  It would be nice to know!

Steve Haflich, MIT Experimental Music Studio