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Path: utzoo!linus!decvax!harpo!gummo!whuxlb!floyd!cmcl2!edler
From: edler@cmcl2.UUCP
Newsgroups: net.lang.c
Subject: Re: Funny bugs in some C compilers - (nf)
Message-ID: <33210@cmcl2.UUCP>
Date: Wed, 14-Sep-83 16:55:09 EDT
Article-I.D.: cmcl2.33210
Posted: Wed Sep 14 16:55:09 1983
Date-Received: Thu, 15-Sep-83 06:09:35 EDT
Sender: edler@cmcl2.UUCP
Organization: New York University
Lines: 27

#R:wateng:-27500:cmcl2:15400004:000:711
cmcl2!edler    Sep 14 16:54:00 1983

The following suggestion has been made:

	Permit comparison of two structures of the same tag or typedef
	for [in]equality only.  If the structure template involved contains
	no holes, compare the structures using a block-compare instruction
	(if available).  If there ARE holes, the result is the && conjunction
	[|| disjunction] of comparisons for [in]equality of constituent blocks
	that have no holes.
	
This won't work for structures containing unions of different-sized
components.  For example, I don't see how any C compiler can compare
two instances of the following structure:

	struct a {
		int b;
		union {
			char c;
			long d;
		} e;
	};

	Jan Edler	cmcl2!edler	(New York University)
			edler@nyu