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From: bright@dataioDataio.UUCP (Walter Bright)
Newsgroups: net.lang.c
Subject: Re: Error recovery (long)
Message-ID: <1009@dataioDataio.UUCP>
Date: Thu, 29-May-86 13:15:51 EDT
Article-I.D.: dataioDa.1009
Posted: Thu May 29 13:15:51 1986
Date-Received: Tue, 3-Jun-86 20:54:52 EDT
References: <312@uw-nsr.UUCP>
Reply-To: bright@dataio.UUCP (Walter Bright
Distribution: net
Organization: Data I/O Corp., Redmond WA
Lines: 22

In article <312@uw-nsr.UUCP> john@uw-nsr.UUCP (John Sambrook) writes:
>While on the subject of compilers, I would like to share two other features
>of this compiler that I find useful.
>The second feature is the ability to declare certain data structures as
>"read only." This is done via a compiler switch "-R" and applies to all 
>data structures that are initialized to a constant value within the 
>compilation unit.
>
>	int a = 1;					/* "read only" */
>	main() {
>	    	int	b;				/* "read / write" */
>
>		b = a;		/* this is legal */
>		a = 2;		/* this is not */
>	}

The declaration for a can be made 'read only' by declaring it as follows:

	const int a = 1;

Doing an assignment to a will then cause a syntax error when compiling.
This is in the draft ANSI C spec.