Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!cbatt!ihnp4!houxm!hoqam!vedm
From: vedm@hoqam.UUCP (BEATTIE)
Newsgroups: net.lang.c
Subject: Re: sizeof (int) - 1
Message-ID: <271@hoqam.UUCP>
Date: Tue, 30-Sep-86 08:49:25 EDT
Article-I.D.: hoqam.271
Posted: Tue Sep 30 08:49:25 1986
Date-Received: Wed, 1-Oct-86 05:15:42 EDT
References: <102500008@uiucuxc>
Organization: AT&T Bell Laboratories, Holmdel
Lines: 20

> 
> It is interesting that the expression
> 	sizeof (int) - 1
> is ambiguous in C, for it can be parsed as
> 	sizeof ((int)(- 1))
> or as
> 	(sizeof(int)) - 1
> 
> Think about it!
> 
> The unix compiler does it the second way, for when it sees the '-' it
> sets the precedence for that character ASSUMING it will be used as a
> binary operator.

There is nothing ambiguous about it.
K&R p188:
"The construction   sizeof(type)  is taken to be a unit, so the
expression  sizeof(type)-2  is the same as (sizeof(type))-2."
Tom.
...!{decvax | ucbvax}!ihnp4!hoqax!twb